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Studies toward the synthesis of ptilomycalin A analogs

Grillot, Anne-Laure, Ph.D.

The Ohio State University, 1993

UMI 300 N. ZeebRd. Ann Arbor, M I 48106 STUDIES TOWARD THE SYNTHESIS OF PTILOMYCALIN A ANALOGS

DISSERTATION

Presented in Partial Fulfillment of the Requirements for

the Degree Doctor of Philosophy in the Graduate

School of the Ohio State University

Anne-Laure Grillot

The Ohio State University

1 9 9 3

Dissertation Committee: Approved by

Dr. David J. Hart

Dr. Leo A. Paquette

Dr. Viresh H. Rawal Adviser Department of Chemistry To My Parents ACKNOWLEDGEMENTS

I wish to thank my adviser, Dr. David J. Hart, for his support, encouragement and guidance throughout my graduate work at the Ohio State University. His enthusiasm for chemistry and his sharing of knowledge were highly motivating, and his nice attitude about life helped to make my stay enjoyable. I would also like to thank Dr. Jean Huet from the Lyon School of Chemistry (France) for providing me with the opportunity to study in the United States.

Past and present group members are greatly acknowledged. Special thanks go to Brian

Filippini for being such a good labmate, for proofreading this thesis and for providing me with

"hints" about America and American people. I also thank Vincent Leroy for encouraging me when the work got tough, and for helpful discussions.

Next, I wish to thank Carl Engelman, Dr. Dirk Friedrich and Dr. Charles Cottrell for recording 13C NMR spectra and running other NMR experiments, as well as Dr. David Chang for recording mass spectra.

Finally, I wish to acknowledge my friends in Columbus for their help and support. I also wish to express my sincere gratitude to my parents for their emotional and financial support during my undergraduate and graduate studies. VITA

September, 13, 1967 ...... Bom, LaTronche, France.

1984-1986 ...... Mathematiques Superieures and Mathematiques Spedales, Lycee Champollion, Grenoble, France.

1986-1988 ...... Engineer Degree, ESCIL, Lyon, France. 1988-1991 ...... Teaching Assistant, The Ohio State University, Columbus. 1992-1993 ...... Research Assistant, The Ohio State University, Columbus.

PUBLICATIONS

Grillot, A.-L.*; Hart, D. J. "Studies Toward the Synthesis of Ptilomycalin A Analogs", 25th Central Regional Meeting of the American Chemical Society, Pittsburgh, Pa, October 4-6,1993.

FIELD OF STUDY

Major Reid: Chemistry Studies in Organic Chemistry

IV TABLE OF CONTENTS

DEDICATION...... ii ACKNOWLEDGEMENTS...... iii VITA...... iv LIST OF FIGURES...... viii LIST OF SCHEMES...... ix

CHAPTER PAGE

I ISOLATION, STRUCTURE DETERMINATION AND BIOLOGICAL ACTIVITY OF PTILOMYCALIN A AND RELATED COMPOUNDS...... 1

A. Introduction ...... 1 B. A New Class ot Biologically Active Marine Alkaloids: Isolation, Biological Activity and Structure Elucidation ...... 1 C. Objectives ...... 7

II A SURVEY OF LITERATURE METHODOLOGIES FOR THE SYNTHESIS OF GUANIDINES...... 9

A. General Methods ...... 10 B. Synthesis of Chiral, C 2 Symmetric Bicyclic Guanidines ...... 21 C. Synthesis of Guanidine-Containing Natural Products ...... 26

III SYNTHESIS OF THE AMIDO-ALCOHOL PORTION OF PTILOMYCALIN ...... A 35

A. Retrosynthetic Analysis .35 B. Synthesis of the Amido-Alcohol Portion of Ptilomycalin A ...... 35 C. Synthesis of Acetate 7 ...... 40

IV SYNTHESIS OF A SIMPLE STRUCTURAL ANALOG OF PTILOMYCALIN ...... A 42

A. Introduction ...... 42 B. Attempted Synthesis of Guanidine 177 via an Intermediate Monocyclic Guanidine ...... 42 C. Attempted Synthesis of Guanidine 177 via an Intermediate Monocyclic Urea ...... 46 D. Attempted Synthesis of Guanidine 177 via an Intermediate Acyclic Triamine ...... 56 E. Synthesis of Guanidine 177 via an Intermediate Acyclic Triamine 59 F. Synthesis of Ptilomycalin A Analog 14 ...... 64

V STUDIES TOWARD THE SYNTHESIS OF A TRICYCLIC STRUCTURAL ANALOG OF PTILOMYCALIN A...... 70

A. Retrosynthetic Analysis ...... 70 B. Synthesis of a Thiolactam of Type 281 ...... 72 C. Sulfide Contraction ...... 74 D. One-Carbon Homologation ...... 78 E. Attempted Double Bond Reduction ...... 79

VI STUDIES TOWARD THE SYNTHESIS OF A PENTACYCLIC STRUCTURAL ANALOG OF PTILOMYCALIN A...... 83

A. Retrosynthetic Analysis ...... 83 B. Synthesis of a Vinylogous Amide of Type 320 ...... 84 C. Double Bond Reduction and Stereochemistry Determination ...... 93 D. Studies Toward the Synthesis of a Compound of Type 318 ...... 98

VII RECENTLY PUBLISHED APPROACHES TO THE TOTAL SYNTHESIS OF PTILOMYCALIN A AND GENERAL CONCLUSION...... 102

vi A. Introduction ...... 102 B. A Biomimetic Synthesis of the Internal Tricyclic Core of Ptilomycalin A ...... 102 C. Synthesis of an Advanced Intermediate en Route to the Total Synthesis of Ptilomycalin A ...... 105 D. Conclusion ...... 107

VIII EXPERIMENTAL...... 108

LIST OF REFERENCES...... 202 APPENDIX...... 209 1H NMR and 13C NMR Spectra of Selected Compounds

vii LIST OF FIGURES

FIGURE PAGE

1. The Structure of Ptilomycalin A and Derivatives ...... 2

2. Spermidine Derivatives ...... 3

3. A Possible Conformation for 2 ...... 4

4. The Crambescidins Alkaloidslrom Crambe crambe ...... 5

5. 13,14,15-lsocrambescidin ...... 6

6 . The Absolute Stereochemistry of the Crambescidins ...... 7

7. The Amido-Alcohol Portion of Ptilomycalin A ...... 7

8 . Three Structural Analogs of Ptilomycalin A ...... 8

9. FAB Mass Spectrum of 276 ...... 67

10. Guanidinium Carboxylate Self-Association ...... 67

1 1 . NOE Experiments on Cyclic Carbamates 353 and 354 ...... 97

viii LIST OF SCHEMES

SCHEMES PAGE

I. Rathke's Guanidine Synthesis ...... 10

II. Elderfield's Preparation of Cyclic Guanidines ...... 10

III. The Conversion of Nitroguanidines to Alkyl or Aryl Guanidines ...... 11

IV. Synthesis of Bicyclic Guanidines 2 5 ...... 11

V. Mackay's Synthesis of Bicyclic Ketoguanidines 2 8 ...... 11

VI. Preparation of Guanidines 31 via an Intramolecular Sn2 Process ...... 12

VII. Cyclization of Amino-Thiourea 32 ...... 12

VIII. Synthesis of Guanidines 38-40 via an intramolecular N-Alkylation ...... 13

IX. Senning's Synthesis of A/-Sulfonyl Guanidines ...... 13

X. Synthesis of Acyclic Guanidine Diester 5 2 ...... 14

XI. Two routes to Guanidine 55 ...... 15

XII. Preparation of Guanidine 6 0 ...... 16

XIII. Cyclic Guanidino Diester Synthesis ...... 17

XIV. Rapoport's Synthesis of Cyclic Guanidino Ketones ...... 17

XV. Schmidtchen’s Synthesis of Symmetric Bicyclic Guanidines ...... 18

XVI. Synthesis of Hindered Guanidines ...... 19

XVII. Esser's Bicyclic Guanidines Synthesis ...... 20

XVIII. Echavarren and Lehn's Synthesis of Bicyclic Guanidine 94 ...... 21

XIX Corey's Synthesis of Bicyclic Guanidine 99 ...... 22

ix Schmidtchen's Synthesis of Guanidine 94 ...... 23

Schmidtchen's Large-Scale Synthesis of Guanidine 94.. .24

Synthesis of Tetrasubstituted Bicyclic Guanidine 113.... .25

Kishi's Total Synthesis of dl-Tetrodotoxin ...... 27

Kishi's Synthesis of dl-Saxitoxin 130 ...... 28

Jacobi's Synthesis of Saxitoxin ...... 30

Snider's Total Synthesis of (±) and (-)-Ptilocaulin ...... 32

Roush's Total Synthesis of (-)-Ptilocaulin ...... 33

Retrosynthetic Analysis of Compounds 158 and 7 ...... 36

Synthesis of Carboxylic Acid 166 ...... 37

Fujita's Synthesis of Spermidine Derivative 169 ...... 37

Synthesis of Spermidine Derivative 172 ...... 38

Synthesis of Amido-Alcohol 174 ...... 39

Synthesis of Acetate 7 from Amide 173 ...... 40

Retrosynthetic Analysis of Analog 14 ...... 43

First Retrosynthetic Analysis of Guanidine 177 ...... 43

Synthesis of Ethyl 2-Bromomethylacrylate 182 ...... 44

Attempted Synthesis of Monocyclic Guanidine 178 ...... 45

Retrosynthesis of Guanidine 177 via a Monocyclic Urea .46

Field's Preparation of Urea 198 ...... 47

Synthesis and Attempted Deprotection of Urea 200 ...... 48

Synthesis and Attempted N-Alkylation of Urea 202 ...... 48

P-Elimination of Acrolein ...... 49

Preparation of Urea 195 ...... 50

Desymmetrization of Diol 195 ...... 51

Preparation of Alcohol 219 ...... 52

Attempted Three-Carbon Unit Elimination ...... 52

Allyl Moiety Cleavage ...... 54

x XLVIII. Marquet's Allyl Urea Isomerization and Cleavage ...... 55

XLIX. Attempted Thiourea Synthesis ...... 56

L. Retrosynthetic Analysis of Guanidine 177 via an Acyclic Triamine ...... 57

LI. Synthesis of Diol 242 ...... 57

Lll. Synthesis of Alcohol 2 4 7 ...... 58

UN. Attempted Three-Carbon Unit Elimination from 247 ...... 59

LIV. Asymmetric Synthesis of p-Amino-Acid Derivatives ...... 60

LV. Retrosynthesis of Guanidine 177 via a Disymmetric Diamine ...... 60

LVI. Attempted Synthesis of 258 from Acrylate 182 ...... 61

LVII. Synthesis of Alcohol 26 5 ...... 62

LVIII. Synthesis of Amine Equivalent 269 ...... 63

LIX. Synthesis of Guanidine 274 ...... 64

LX. Dicyclohexylcarbodiimide-Mediated Coupling of 274 and 174 ...... 65

LXI. Attempted Cleavage of the Sulfonamide Moiety in 275 ...... 66

LXII. Fluoride-Mediated Cleavage of Sulfonyl-Guanidine 274 ...... 66

LXIII. Synthesis of Analog 1 4 ...... 68

LXIV. Retrosynthetic Analysis of Analog 15 ...... 71

LXV. Retrosynthetic Analysis of Guanidine 278 ...... 71

LXVI. Preparation and Attempted Reduction of Ester 283 ...... 72

LXVII. Preparation and Attempted Transformations of Ester 284 ...... 72

LXVIII. Synthesis of Thiolactam 287 ...... 73

LXIX. Attempted Nitrile Synthesis from Alcohol 287 ...... 74

LXX. Eschenmoser's Sulfide Contraction ...... 75

LXXI. Synthesis of Vinylogous Amides and Urethanes via

(Methylthio)alkylideniminium salts ...... 75

LXXII. Synthesis of Salt 298 ...... 76

LXXIII. Preparation of p-Ketoesters 300 and 302 ...... 76

LXXIV. Synthesis of Vinylogous Urethanes 303,304 and 305 ...... 77

xi LXXV. One-Carbon Homologation of 305 ...... 78

LXXVI. Attempted Reduction of 305 ...... 79

LXXVII. Attempted Reduction of 308 ...... 80

LXXVIII. Attempted Reduction of Nitrile 309 ...... 80

LXXIX. Mechanism for the Ionic Reduction of 309 ...... 81

LXXX. Bachi's Reduction of Vinylogous Urethane 313 ...... 82

LXXXI. Retrosynthetic Analysis of Analog 16 ...... 84

LXXXII. Retrosynthetic Analysis of Pentacyclic Structure 316 ...... 85

LXXXIII. Preparation of Vinylogous Amide 321

LXXXIV. Alkylation and Reduction of Vinylogous Amide 321 ...... 8 6

LXXXV. Low-Yielding Synthesis of a-Bromoketone 328 ...... 87

LXXXVI. Efficient Synthesis of a-Bromoketone 328 ...... 8 8

LXXXVII. Synthesis and Deprotection of Vinylogous Amide 334 ...... 89

LXXXVIII. Benzylation of Alcohol 287

LXXXIX. Synthesis of Vinylogous Amide 337 ...... 90

XC. Attempted Deprotection of Vinylogous Amide 337 ...... 91

XCI. Attempted Deprotection of Thiolactam 336 ...... 91

XCII. Synthesis of Lactam 340 ...... 92

XCIII. Synthesis of Vinylogous Amide 342 ...... 93

XCIV. Reduction of Vinylogous Amide 342 ...... 94

XCV. Hydroxyl Group Reduction in Amino-Alcohols 343 and 344...... 95

XCVI. Synthesis of Carbamates 353 and 354 ...... 96

XCVII. Rapoport's Reduction of Vinylogous Carbamate 355 ...... 97

XCVIII. Synthesis of Cyclic Ureas 364 and 365 ...... 98

XCIX. Alternative Stereochemical Outcome for the Reduction of 342 ...... 100

C. Snider's Strategy for the Synthesis of Crambines A and B ...... 103

Cl. Snider's Synthesis of the Internal Tricyclic Core of Ptilomycalin A ...... 104

Cll. Synthesis of Tricyclic Intermediate 389 ...... 106

xii CHAPTER I

ISOLATION, STRUCTURE DETERMINATION AND BIOLOGICAL

ACTIVITY OF PTILOMYCALIN A AND RELATED COMPOUNDS.

A. Introduction.

This thesis describes the synthesis of a structural analog of ptilomycalin A, as well as

approaches to two other analogs. The results of our studies will be presented in seven chapters. Chapter I will describe the isolation, structure elucidation and biological activity of

ptilomycalin A and related compounds. The objectives of our studies will also be defined. In chapter II, literature methodologies for the synthesis of guanidines will be presented, as well as their applications to the synthesis of chiral bicyclic guanidines and guanidine-containing natural

products. Chapter III will present our synthesis of the amido-alcohol portion of ptilomycalin A and chapter IV will describe the synthesis of a simple analog of ptilomycalin A. Chapters V and VI will

discuss our studies toward two additional analogs. Finally, recently published approaches to

ptilomycalin A will be presented in chapter VII.

B. A New Class of Biologically Active Marine Alkaloids: Isolation, Biological

Activity and Structure Determination.

Ptilomycalin A (1, Figure 1) is a naturally occurring polycyclic marine alkaloid. It has been isolated in 1989 by Kashman and coworkers 1-2 from the Caribbean sponge Ptilocaulis Spiculifer

1 2 and from a Red Sea sponge of the Hemimycale species. Ptilomycalin A is a potent biologically

active compound which shows cytotoxicity against P388 (IC 50 = 0.1 pg/mL), L1210 (IC50 = 0.4

pg/mL) and KB (IC 50 = 0.4 pg/mL) tumor cell lines, it exhibits antifungal activity against Candida

albicans (MIC = 0.8 pg/mL), as well as very good antiviral activity against HSV at a concentration of 0.2 pg/mL.

Ptilomycalin A was isolated as an oil. Its specific rotation was found to be -2.5 0 (c 0.70,

CHCI3) and a mass spectrum gave a peak at m/e 785 (MH+). Intense absorptions in the infrared

spectrum at 3600-3400,1730 and 1650 cm *1 indicated the presence of OH or NH, ester and

amide moieties. However, the 1H NMR spectrum only gave broad signals and many peaks in the

13C NMR spectrum overlapped. The structure elucidation work was therefore performed on the

bis(trifluoroacetamide) derivative 2 (Figure 1).

NH Me NHR

NHR

1 Ptilomycalin A: R=H, X=unknown 2 R=COCF3, x =c f 3c o o 3 R=COC6H4Br-p, X=p-BrC6H4COO

Figure 1. The Structure of Ptilomycalin A and Derivatives

Compound 2 was found to be an oil with a specific rotation of -15.8° (c 0.68, CHCI 3).

High resolution FAB MS of 2 gave the molecular formula C 4 9 H7 8 N6O 7 F6 . Chemical 3 degradation of 2 afforded complex mixtures. Therefore, the structural elucidation was based on

mass spectroscopy and NMR techniques.

Ptilomycalin A can be divided into two subunits: a "vessel" subunit from C-1 to C-22,

and an "anchor" subunit from C-23 to C-45. NMR experiments determined that the anchor unit

contained a spermidine moiety which had been bistrifluoroacetylated at the two primary amino

groups. Smaller signals in the 1H and 13C NMR spectra indicated the presence of rotational

isomers. This was confirmed by synthesizing compound 4 (Figure 2) and comparing its NMR

data to those of 2. The presence in 1 of a long chain of methylene groups was suggested by a

signal at 6 1.25-1.28 ppm in the 1H NMR spectrum. A fragment of m/e 612 accompanied by

peaks resulting from loss of methylene units in the mass spectrum confirmed this suggestion.

Furthermore, compound 5 (Figure 2) was isolated from both sponges and converted to its

bis(trifluoroacetyl) derivative 6 (Figure 2 ). Its mass spectrum showed the presence of a

hexadecanoyl unit. By treating 2 with sodium methoxide/methanol or with lithium aluminum

hydride, compound 7 was isolated after acetylation. Compound 3 (Figure 1) could be degraded in the same manner to afford alcohol 8 (Figure 2). The anchor unit of 2 was therefore

identified as (16-hydroxyhexadecanoyi)spermidine which must be attached to the vessel by the terminal hydroxyl group.

NHR1

4 R = CF3, R’ = COCF3 5 R = CH3(CH2)14, R' = H 6 R = CH3(CH 2) i 4, R’ = COCF3 7 R = AcO(CH2)is, R' = COCF3 8 R = HO(CH2)15, R’ = COC6H4Br-p

Figure 2. Spermidine Derivatives 4 The structure of the vessel unit of molecular formula C 22H32N2O3 was determined using NMR techniques. Two signals in the 1H NMR spectrum at S 10.22 and 9.87 ppm were

D2O exchangeable and could belong to a salt. The presence of a salt was confirmed by the proton-decoupled 13C NMR spectrum, which showed a quartet at 8116.8 ppm and a quartet at 8

162.7 ppm, both characteristic of a trifluoroacetate anion. The two downfield signals in the 1H

NMR spectrum disappeared upon washing a CDCI 3 solution of 2 with 1 M aqueous sodium hydroxide but slowly regenerated on standing, suggesting the presence of a strongly basic moiety such as a guanidine. Moreover, the COLOC and HBMC spectra showed that one carbon signal (8 149.09 ppm) was not correlated to any hydrogen. This signal split into three peaks when the 13C NMR spectrum was taken in the presence of three molar equivalents of CD 3OD, due to an isotope effect. All these data strongly pointed to a guanidinium moiety. Carbon- hydrogen correlation spectra established the planar structure of the vessel unit of ptilomycalin

A. The COLOC spectrum established correlation between C -22 (8 1 68.6 ppm) and the C-23 methylene (8 4.08 and 4.05 ppm) and proved that the hydroxyl terminus of the anchor was attached to the vessel via an ester linkage. The relative stereochemistry of 2 was established by

NOESY and ROESY experiments.

Figure 3. A Possible Conformation for 2

The rotational isomerism around the amide linkage at C-38 was also studied .2-3

Trifluoroacetyl derivatives of spermidine, dipropylenetriamine, diethylenetriamine and 5 pentylamine were synthesized and their NMR properties were studied. From these experiments, a possible conformation of compounds 1 and 2 was suggested and is shown in

Figure 3.

It was also shown that compound 2 was able to select its counter anion, as it formed a complex more readily with certain organic carboxylates .2

9 Crambescidin 816: R=OH, n=1 10 Crambescidin 830: R=OH, n=2 11 Crambescidin 844: R=OH, n=3 12 Crambescidin 800: R=H, n=1

Figure 4. The Crambescidins Alkaloids from Crambe crambe

In 1991, four new marine alkaloids of the same family were reported by Rinehart and coworkers .4 Crambescidin 816 (9), crambescidin 830 (10), crambescidin 844 ( 1 1 ) and crambescidin 800 (12) (Figure 4) were isolated from the Mediterranean sponge Crambe crambe. Extracts of this sponge had been found to be biologically active against HSV-1 and cytotoxic to L1210 murine leukemia cells. Crambescidins 816, 844 and 800 inhibit HSV -1 completely with diffuse toxicity at 1.25 pg/well and are 98% effective against L1210 cell growth at 0.1 pg/mL. Crambescidin 816 (9) differs from ptilomycalin A in that hydroxyl groups appear at

C-13 and C-43. The vessel subunit of crambescidins 820 (10) and 844 (11) is the same as crambescidin 816 (9) but compound 10 has one additional methylene in the anchor part and 6 compound 11 has two. Crambescidin 800 (12) exhibits the same vessel structure as ptilomycalin A, but has one hydroxyl group at C-43. The structure of the crambescidins was elucidated using mass spectroscopy and NMR techniques. No absolute stereochemistry was assigned at that point.

In 1993, 13,14,15-isocrambescidin 800 (13) (Figure 5) was isolated from the same sponge by Rinehart and coworkers .5 Compound 13 was less cytotoxic to L1210 cells as it showed a 10% inhibition at 10 pg/mL, and had no antiviral activity against HSV-1. The structure of 13 was elucidated using the same techniques described above.

Me 2

Figure 5. 13,14,15-isocrambescidin

The absolute stereochemistry of the crambescidins was also elucidated at that point by

Rinehart and coworkers .5 Ozonolysis of compounds 9 and 13 followed by treatment with hydrogen peroxide, acid hydrolysis and methylation afforded mixtures containing methyl 2 - hydroxybutanoate derived from the C-1 to C-4 portions of 9 and 13. Chiral GC/MS analysis of this product and authentic samples of methyl (2S) and (2 R) 2-hydroxybutanoate established that the ozonolysis product was methyl ( 2 S) 2-hydroxybutanoate. The absolute stereochemistry of the crambescidins is therefore depicted in Figure 6 , which is the mirror image of the structures arbitrarily shown for ptilomycalin A and the crambescidins. Figure 6. The Absolute Stereochemistry of the Crambescidins

C. Objectives.

This research had two main objectives. The first objective was the synthesis of the

amido-alcohol portion of ptilomycatin A, shown in Figure 7.

^ .N H R

Figure 7. The Amido-Alcohol Portion of Ptilomycalin A

The second objective was to develop methodology for the synthesis of three structural

analogs to ptilomycalin A (Figure 8 ), which would eventually lead to the total synthesis of the

natural product. Analog 14 contains a bicyclic guanidine attached via an ester linkage to the

amido-alcohol portion of Ptilomycalin A. Synthesizing this analog would provide us with a general route for the introduction of the guanidine moiety, as well as an evaluation of the functional groups required for biological activity. In analog 15, the vessel unit is made of a tricyclic guanidine structure. Starting from an enantiomerically pure starting material would address the c/s-stereochemistry problem. Analog 16 contains a pentacyclic guanidine subunit.

Its synthesis would address the amidal moiety synthesis problem. 8 Q NH N'*NH NH .NH,

XO' O f O '^ 'O ^(C H z'CY X 7

1 4 1 5

1 6

Figure 8. Three Structural Analogs of Ptilomycalin A

Our efforts toward the synthesis of these four targets are discussed in the following chapters. However, a survey of literature methodologies for guanidine synthesis will first be outlined in the next chapter. CHAPTER II

A SURVEY OF LITERATURE METHODOLOGIES FOR

THE SYNTHESIS OF GUANIDINES.

Guanidine-containing compounds are widely found in nature, and are of biological interest. For instance, the guanidine moiety is part of the amino-acid arginine and the glycocyamidines creatine and creatinine. In the last thirty years, the guanidine functional group has been found in a variety of compounds as part of a monocyclic, bicyclic or tricyclic system.

Guanidine-containing natural products include the puffer fish poison tetrodotoxin ,6 the paralytic shellfish poison saxitoxin ,7 the peptide antibiotics capreomycin ,8 viomycin ,9 and tuberactinomycin ,10 the antifungal agent stendomycin ,11 the Alchornea javanensis alkaloids alchorneine and isoalchorneine ,12 and the sponge alkaloids ptilocaulin and isoptilocaulin ,13 crambine A and B ,14 ptilomycalin A ,1-2 and crambescidins 816,830,844, and 800.4-5

A wide number of methodologies for the synthesis of guanidines is available in the literature, although only a few of them can be adapted to the synthesis of polycyclic guanidines.

A survey of these methods will be presented in this chapter, as well as a summary of their application to chiral bicyclic guanidine synthesis, and natural product synthesis.

9 10 A. General Methods.

Literature methodologies for the synthesis of guanidines are outlined in a review by

Kuehle published in 1983.15 The first synthesis of guanidines was reported by Rathke in

1881.16 The reaction of thiourea 17 with ethyl bromide or ethyl iodide afforded S-ethyl isothiourea 18 which upon treatment with ammonia yielded guanidine 19 (Scheme I).

Scheme I. Rathke’s Guanidine Synthesis

S SEt NHZ

%A n ' b EtBr or Etl h- n *L n - r nh3 %A n , r | | I 1 H H H H

17 R = H, Ph 1 8 19

Another method for the synthesis of guanidines involves the reaction of a cyanamide with a primary or a secondary amine. This reaction was exemplified by Elderfield and coworkers, who prepared cyclic guanidines of type 21 starting from bromoethyl alkyl cyanamide 2 0

(Scheme II ) .17 Some amino acid residues were also introduced in molecules of type 21 by using the potassium or sodium salt of an amino acid as the starting amine.17b

Scheme II. Elderfield's Preparation of Cyclic Guanidines

RNH2, EtOH N' I CN

2 0 21 R = alkyl, aryl (77-95%)

In 1949, Mackay and coworkers reported that cyclic nitroguanidines of type 22 ,22 upon reaction with various alkyl and aryl amines, yielded the corresponding cyclic guanidines 23 in 11 good to excellent yield (Scheme III ).23

Scheme III. The Conversion of Nitroguanidines to Alkyl or Aryl Guanidines

^ xylenes ^ A reflux A HN S N . R-— NH2 ------► HN n N h * >» W h R R

22 R = H, CH3 Hf = alkyl 23 (76-99%) n = 1,2 aryl

This reaction was later applied to the synthesis of bicyclic guanidines .20 For example, reactions of 1-(p-chloroethyl)-2-nitriminoimidazolidine 24 with primary amines afforded bicyclic guanidines of type 25 (Scheme IV).

Scheme IV. Synthesis of Bicyclic Guanidines 25

,— i toluene _ . N N w re,,ux H'Ny + r--nh 2 ^

NN02 R

2 4 R' = PhCH2, (i-Pr) 2NCH2CH2 25

Scheme V. Mackay's Synthesis of Bicyclic Ketoguanidlnes 28

COOH H

?Me H2 N ^ C O O H j }) VN-4 v)m HN^'" b, C / X

HN NH ------► I ► , A n A 0 >—{/)„ a n^ nh m = 1 ,2 w n

26 n = 1, 2 27 (60-87%) 28 (50-60%)

(a) NaOH, H20; (b) HCI, EtOH, C 6H6; (c) Ag20, H20. 12 In 1956, the methodology first reported by Rathke was applied by Mackay and coworkers to the synthesis of cyclic guanidino acids .21 The reaction of methyl isothiouronium salts 26 with glycine or valine yielded cyclic guanidino acids of type 27 in good yield (Scheme

V). Cyclization to ketoguanidines 28 was accomplished by esterification, followed by treatment with silver oxide.

Mackay then extended this methodology to the intramolecular version, hereby providing a route to bicyclic guanidines .22 The reaction of methyl 2 -(p-hydoxyethyl)isothiourea

29 with various alkyl and aryl amines afforded monocyclic guanidines of type 30 in good yield.

Conversion of the hydroxyl group in 30 into the corresponding chloride, followed by potassium

hydroxide-mediated cyclization yielded bicyclic guanidines of type 31 (Scheme Vl).22a

Scheme VI. Preparation of Guanidines 31 via an Intramolecular Sn 2 Process

R = alkyl 2 9 aryi 30(55-100%) 31 (37-70%)

(a) MeOH; (b) SOCI2l CHCI3; (c) KOH, MeOH.

A variant of this reaction is shown in Scheme VII. Activation of thiourea 32 with chloroacetic acid afforded 2,3,5,6-tetrahydro-1-imidaz(1,2-a)imidazole 33 in high yield .22*3

Scheme VII. Cyclization of Amino-Thlourea 32 13 Three other unprotected bicyclic guanidines were synthesized using this general method (Scheme Vlll).22c Thioureas of type 34 were converted in two steps into W-(p- chloroethyl)guanidinium chloride 35,36 and 37. The intramolecular N-alkylation to guanidines

38 and 39 proceeded in acceptable yield. However, the poor yield of formation of guanidine

40 illustrates the limitations of this method.

Scheme VIII. Synthesis of Guanidines 38-40 via an Intramolecular N-Alkylation

,COOH

34 n = 1, 2 m = 1,2 35 n = 1, m = 1 (98%) 38 n = 1, m = 1 (70%) X = Cl,I 36n = 2, m = 1 (100%) 39 n = 2, m = 1 (63%) 37 n = 1, m = 2 (100%) 40 n = 1, m = 2 (26%)

(a) EtOH; (b) SOCI2, CHCI3; (c) KOH, MeOH.

Scheme IX. Senning's Synthesis of W-Sulfonyl Guanidines

^SOaRi S N

FW X „R4 benzene r 2 v X , r 4 R,S02-N = S=0 + 2 >*N^N' ► N' N i i reflux i i R3 r s R3 r s

4 1 4 2 43 (4-69%)

ySOoRi SMe N

.... r2^ X-..^r4 xylenes R2v X. ^ R4 R,S02—NHz + ZXN N ' 4 — ------* - N N WR13 ref,UX R1 ri3 H n

44 4 5 46 (7-73%)

R l. R2. R3. ^4. ^5 = H, alkyl 14 In 1961 and 1964, two related methods for the synthesis of acyclic and monocyclic N- sulfonyl guanidines were reported by Senning .23 /V-Sulfinyl sulfonamides 41 reacted with thioureas 42 in an equimolar ratio to afford A/-sulfonyl guanidines 43. Similarly, the reaction of sulfonamides 44 with methyl isothioureas 45 yielded /V-sulfonyl guanidines 46 (Scheme IX).

The yields for these transformations ranged from 4% to 73%.

In 1973, Rapoport recognized the lack of flexible methodologies for guanidine synthesis and reported four new routes to tosyl protected guanidine diesters 24 As shown in

Scheme X, the first synthesis started with S,S-dimethyl*A/-p-toluenesulfonate-iminodithiocarbonimidate 47. Reaction of 47 with one equivalent of p-alanine afforded compound

48. After esterification, compound 49 was reacted with chlorine in acetic acid to afford intermediate 50 or 51, which upon treatment with ethyl 3-/V-methylaminopropanoate, afforded guanidine 52.

Scheme X. Synthesis of Acyclic Guanidine Diester 52

SCH, SCH, ,Ts N x TsN =< TsN =< CH3 S SCH3 -COOH H -COOMe

4 7 48 (71%) 49 (61%)

Me -COOEt Cl N- T s N = C = N - TsN TsN or =< = < -COOMe N- N- / H -COOMe H '— COOMe 5 0 51 52 (68 %)

(a) H2NCH2CH2COOH, NaOH, EtOH; (b) Mel, MeOH; (c) Cl2, HOAc; (d) MeNHCH 2CH2COOEt, Et3N, CH3CN. 15 When compound 47 was reacted with sulfuryl chloride, the monochloro derivative 53 was obtained, which subsequently underwent a nucleophilic displacement upon treatment with sarcosine ethyl ester. The resulting S-methyl isothiourea 54 was chlorinated and treated with another equivalent of sarcosine ethyl ester to afford guanidine 55. Upon treatment with neat hydrofluoric acid, the expected tosyl sulfone cleavage took place, along with cyclization to guanidine 56 (Scheme XI). Dissymmetric guanidines other than 55 could also be prepared by this method. Guanidine 55 could also be synthesized by reacting compound 47 with chlorine in acetic acid. The reaction of the dichlorinated product 57 with two equivalents of sarcosine ethyl ester yielded compound 55 in 75% yield (Scheme XI).

Scheme XI. Two Routes to Guanidine 55

,Ts , SCR N SCH, . / 3 ji a » ™=< —£— TsN=< CH3S^ S C H 3 Cl N Me COOEt

4 7 53 (68 %) 54 (87%)

c, a COOEt

Me" N-^ Me Me \ COOEt N TsN =< V N - ^ Me COOEt

56 (88 %) 55 (57%)

Me COOEt „Ts \ N o Cl . N JI ► TsN=/ ► TsN=/ CHjS SCH3 NCI \

Me 7 COOEt

4 7 55 (75%)

(a) S02CI2. CCI4; (b) CH 3NHCH2COOEt, CH3CN; (c) Cl2, HOAc; (d) HF. 16 The last synthesis of acyclic guanidine diesters developed by Rapoport started with p- toluenesulfonate isothiocyanate 58 (Scheme XII). Reaction of 58 with ethyl 3-A/-methylaminopropanoate afforded a quantitative yield of thiourea 59, which was converted to the corresponding S-methyl isothiourea upon treatment with dimethyl sulfate. Guanidine 60 was obtained after treatment with chlorine in acetic acid, followed by reaction with sarcosine ethyl ester.

Scheme XII. Preparation of Guanidine 60

Me COOEt w 'N N * TsN=s^

H k . COOEt N— v Me 7 '— COOEt

5 8 59 (100%) 60 (77%)

(a) MeNHCH 2CH2COOEt, Et20; (b) Me 2S04, N(CH2CH2CH2OH)3, MeOH; (d) MeNHCH 2COOEt, CH3CN.

Cyclic guanidino diesters were also prepared .24 A representative example is shown in

Scheme XIII. Chloropyrimidine 63 could be prepared in two steps from tosylguanidine 61 and diethyl ethoxymethylenemalonate 62. After reduction of the chloride, followed by re- esterification, pyrimidine 64 was obtained in good yield. Alkylation with ethyl bromoacetate took place almost exclusively on the endocyclic nitrogen to afford compound 65 in 85% yield.

Guanidine 6 6 was obtained in 8 6 % yield after hydrogenation of 65. When guanidine 6 6 was treated with neat hydrofluoric acid to effect sulfone cleavage, bicyclic guanidine 67 was isolated, although in poor yield.

Rapoport also applied this methodology to the synthesis of bicyclic guanidino ketones, as shown in Scheme XIV. Reaction of diamines 68 a-b with compound 47 afforded guanidines

69a-b in fair yield. Transketalization followed by fluoride-mediated cleavage of the sulfone moiety yielded guanidines 70a-b, isolated as their hydrochloride salts. 17 Scheme XIII. Cyclic Guanidino Diester Synthesis

NH2 TsN =( NHZ I / S . .COOEt o k COOEt 61 a, b c, d ii + Ts' n ^ n ^ T 8 %n ^ n EtO COOEt j \ = / H COOEt 63 (92%) 64 (83%) 6 2 a, e

v Jn N O' O ■< . N N ^ ISN ZTN v—i h L L o COOEt COOEt

67 (33%) 6 6 (86 %) 65 (85%)

(a) NaOEt. EtOH; (b) POCI3; (c) H2, Pd/C, NaOH; (d) SOCI2, EtOH; (e) BrCH 2COOEt, DMSO; (f) H2. R 0 2, HCI, HOAc; (g) HF.

Scheme XIV. Rapoport’s Synthesis of Cyclic Guanidino Ketones

ft1-I I • ► hn n .. ► HNvft w H T Y H TsT ,' CT + NH*

68 a R = H 69a R =H (65%) 70a R = H (50%) b R = Me b R = Me (54%) b R = Me (70%)

(a) 47, EtOH; (b) p-TsOH, cyclohexanone; (c) HF. 18 Scheme XV. Schmldtchen's Synthesis of Symmetric Bicyclic Guanidines

3. b C, d HOOC. -COOH

HO Ts OH I Ts I R R

7 1 72 (63%) 73a R = Me (73%) b R = allyl (75%)

e-h

H,N NH, io rj HCUHjN NHo.HCI

R R h R R R R Ts R R

75a R = Me (75%) 74a R = Me (72%) b R = allyl (81%) b R = allyl (71%)

R n H,N MC tMH * - morn- »*0 0 <

R R

76a R = Me (81%) 77a R = Me (70%) b R = allyl (80%) b R = allyl (80%)

(a) MsCI, EfeN, CH 2CI2; (b) Nal, acetone; (c) R 2CHCOOEt, LDA, THF; (d) KOH, EtOH; (e) DMF, (COCI)2, C 6H6; (f) NaN3, acetone; (g) reflux, CCI4; (h) HCI; (I) concd. HBr; (j) U/NH3; (k) CI2CS, Et3N, CH2CI2; (I) Mel; (m) MeONa, MeOH; (n) KOf-Bu, f-BuOH; (o) (MeO) 4C, DMSO. 19 In 1980, Schmidtchen reported the synthesis of symmetric 2 ,2 ,8 ,8 -tetraalkyl substituted cyclic guanidines .26 His method involved the synthesis of a triamine and its subsequent cyclization onto an appropriate one-carbon synthon. The synthesis started with sulfonamide 71, which was converted in two steps to the diiodide 72. A four-step sequence afforded dicarboxylic acids 73a (R=Me) and 73b (R=allyl). The corresponding azido ketones were rearranged to the isocyanates, which underwent acidic hydrolysis to afford amines 74a-b.

After cleavage of the sulfonamide moiety, amines 75a-b were converted to thioureas 76a-b.

Activation of the thiocarbonyl moiety with methyl iodide, followed by treatment with base afforded cyclic guanidines 77a-b in very good yield (Scheme XV). Interestingly, Schmidtchen also reported that bis(3-aminopropyl) amine 77, when treated with tetramethylorthocarbonate in dimethyl sulfoxide at 120°C, afforded guanidine 78 in very good yield.

Scheme XVI. Synthesis of Hindered Guanidines

,f-Bu o N a-b R,s J L ,*2 I I I I Ri R2 Ri R2

79a Ri = R 2 = Me 80a (85% ) b R 1 = R2= Et b(48% ) cR 1 = R2 =/-Pr C(62%)

R s N a,c

i i APr APr APr APr

81 82a R = H (81%) b R = Et (85%) cR = /-Pr(69%) d R = f-Bu (38%)

(a) COCI2, CsHs; (b) f-BuNH2, CH 3CN; (c) RNH2, CH3CN. 20 Sterically hindered pentaalkyl guanidines were synthesized in 1982 by Barton and coworkers (Scheme XVI ).27 Treatment of ureas 79a-c with phosgene, followed by reaction with tert-butylamine, afforded guanidines 80a-c. Similarly, submitting thiourea 81 to the same reaction conditions produced guanidines 82a-d. These hindered guanidines were used as organic bases .27

Scheme XVII. Esser's Bicyclic Guanidines Synthesis

*Ar a,b 84 R = H, alkyl (4-92%) R n HN^*N

.Ar

83 n = 1, 2, 3 n N

85 R = Ph (32-73%) v-rr>" Ar

a, b 87 R = H, alkyl (4-92%) R HN I Ar

86 n = 1,2, 3 R jOO N I Ar

88 R = Ph (32-73%)

(a) Hg(OAc)2, THF, H20; (b) NaBH4l NaOH, H 20. 21 The last general method for the synthesis of guanidines was reported by Esser in 1987, and dealt with the synthesis of bicyclic guanidines via intramolecular mercury(ll)-induced amination .28 As shown in Scheme XVII, ring closure reactions of monocyclic guanidines of type

83 and 8 6 followed the Markovnikov rule, and afforded alkyl and aryl-substituted bicyclic guanidines in fair to poor yield.

B. Synthesis of Chiral, C 2 Symmetric Bicyclic Guanidines.

In the last five years, chiral C 2 symmetric bicyclic guanidines have been the focus of a lot of interest, as they can potentially act as oxoanion binders ,29 and may be used as anchor groups in artificial molecular hosts .30 The methodology generally used for the synthesis of such compounds is closely related to the method developed by Schmidtchen and discussed in part

A.26 Starting materials were usually derived from enantiomerically pure amino-acids.

Scheme XVIII. Echavarren and Lehn's Synthesis of Bicyclic Guanidine 94

NH HN ^ I I I I MOMO Ts Ts OMOM MOMO Ts

MOMO H OMOM MOMO OMOM 94 (50%) 93 (58% or 40%) 92 (70%)

(a) CICOOCCI3, PO(OMe)3; (b) NaBH4, MeOH; (c) MeOCH 2OMe, P 20 5,4A sieves, CH 2CI2; (d) Rh/Al 20 3, AcOH, 1 atm. H2; (e) Na/NH3, THF; (f) (lm) 2CS, CH2CI2; (g) (MeO) 4C, DMSO; (h) 12M HCI, MeOH. 22 The first synthesis of a chiral C 2 symmetric bicyclic guanidine was reported by

Echavarren, Lehn and coworkers in 1988 (Scheme XVIII ).31 Compound 89, obtained in two steps from L-asparagine, was converted into nitrile 90 in three steps. Two molecules of 90 were coupled in the presence of rhodium on alumina to afford protected triamine 91 in 60% yield. Sulfonamide cleavage was accomplished by sodium in ammonia reduction to afford triamine 92. Guanidine 93 was then obtained in one step by treating 92 with thiocarbonyldiimidazole (58% yield) or tetramethylorthocarbonate (40% yield). Guanidine 94 was obtained as the hydrochloride salt after MOM ether cleavage.

Scheme XIX. Corey's Synthesis of Bicyclic Guanidine 99

0 -X CH=NH= + 0 ' v - COOH a r

H r H n h n h A h iL Tr CBZ Tr CBZ 9 5 9 6 97 (85%)

b.c

d, e,f

^,NH H NH, i Tr z H 99 (42%) 98 (100%)

(a) DCC, HOBt; (b) Pd/C, MeOH, 1 atm. H2; (c) (Me 0 CH2CH20 )2AIH2Na, C6H6; (d) CSCI2, Et3N; (e) Mel, MeOH; (f) 120°C, DMF.

In 1989, Corey reported the synthesis of bicyclic guanidine 99 (SchemeXIX ).32 The synthesis started with the dicyclohexylcarbodiimide-mediated coupling of amine 95 and carboxylic acid 96, both derived from the commercially available methyl ester of (ft)-(-)-a- phenylglycine. The resulting chiral amide 97 was quantitatively converted to triamine 98 in two steps. Cyclization to bicyclic guanidine 99 was accomplished by treating 98 with 23 thiophosgene, followed by activation of the intermediate thiourea with methyl iodide and subsequent heating in A/, AJ-dimethylformamide. The last step also effected cleavage of the trityl protecting group.

Scheme XX. Schmldtchen's Synthesis of Guanidine 94

H2N ^ |

ukiA ''NH HN CHjOTBDPS NH HN ’CHjjOTBDPS I OMe Ts Ts OMe Ts Ts

100 101 102 (99%)

b, c

d, e

TBDPSOCH2'>. 00 NH2 H2N .c h 2o t b d p s TBDPSOCH j," ^ n h HN CHjOTBDPS I I Ts Ts

104 (67%) 103 (68 %)

f.g

r ^ N ^ l r ^ N ^ l

TBDPSOCH2' CHjOTBDPS HOCH2' N * + * N ^ ^ C H jO H i r i i a - ■ H H H H

105 (73%) 94 (89%)

(a) (lm)2CO, CH2CI2; (b) NaBH4l EtOH; (c) f-Bu(Ph) 2SiCI, imidazole, DMF; (d) BH3, THF; (e) Me 4NI, MeOH, H 20, -2.2V; (f) (MeS) 2CS, MeN02; (g) Mel, AcOH; (h) 3N HCI, CH 3CN.

In 1990, a new synthesis of guanidine 94 was reported by Schmidtchen and coworkers .33 The authors claimed that the previously published synthesis of compound 94 31 24 did not secure the configurational integrity of the starting materials. As shown in Scheme XX, carbonyl diimidazole-mediated coupling of carboxylic acid 100 and amine 101 afforded amide

102 in nearly quantitative yield. After reduction of the methyl ester and protection of the hydroxyl moiety, amide 103 was reduced to triamine 104, which was cyclized to guanidine 105 using dimethyl trithiocarbonate as the one-carbon synthon. Subsequent cleavage of the silyl ethers afforded guanidine 94 in a 20% overall yield.

Scheme XXI. Schmldtchen's Large-Scale Synthesis of Guanidine 94

SCH, SCH,

| ^ n h 2 a, b

HOCH,' MW NH + MN ^C H 2OTBDPS TBDMSOCH,''* NH / ' HN CHaOTBDPS I Ts 106 1 0 7 108 (77%)

C f \ * 6oTe,i HOCH,' N N ^ C H , O H TBDMSOCH,''’ ^ N N ^ C H 2OTBDPS i c r * • H H Ts

94 (80-85%) 109 (87%)

(a) CH3CN, 35°C; (b) TBDMSCI, imidazole, CH 2CI2; (c) MeOTf, EtN(/-Pr)2, CH 2CI2; (d) NH4Br, MeOH, H 20, -2 .2V; (e) Al-Hg, THF, H 20; (f) 3N HCI, CH3CN.

An optimized synthesis of guanidine 94 has also been reported by Schmidtchen and coworkers (Scheme XXI ).34 This alternative pathway started with the coupling of amine 106 and isothiocyanate 107 to afford, after silyl ether formation, the open-chain thiourea 108.

Cyclization to tosyl-guanidine 109 was accomplished using methyl triflate and N,N- diisopropylethylamine. The sulfonamide was efficiently cleaved by electrolysis or by reduction 25 with aluminum amalgam. The final product was obtained as the hydrochloride salt after acidic

hydrolysis of the protecting groups. Guanidine 94 could be prepared in large quantities using

this method and with a diastereomeric excess greater than 98%. Moreover, the corresponding

cis disubstituted guanidine could be synthesized in the same fashion.

Scheme XXII. Synthesis of Tetrasubstltuted Bicyclic Guanidine 113

Me. Me MeO, .OMe

Ts •“A JC” OMe MeO'

7 2 1 1 0 1 1 1

b-e

f-h

TBDPSO OTBDPS TBDPSO OTBDPS

1 1 3 112 (41%)

(a) n-BuLi, THF; (b) 0.2N HCI, CH 3CN; (c) NaBH4l CaCI2, EtOH; (c) (Ph) 2f-BuSiCI, imidazole, DMF; (d) EUNBr, CH3CN, H20, -2 .2V; (e) CSCI2, EtN(APr)2, CH 3CN; (f) HOAc, Mel; (g) EtN(/-Pr)2.

Finally, a synthesis of tetrasubstituted, C 2 symmetric, bicyclic guanidine 113 was

reported in 1991 by Schmidtchen and coworkers .35 The synthesis was based on a similar

strategy and started with the asymmetric alkylation of lactim ether 110. Reaction of two

equivalents of compound 110 with diiodide 72 afforded compound 111 as a single diastereomer (de>95%). Acidic hydrolysis afforded the corresponding bismethyl ester, which was reduced and protected to the bissilyl ether. The sulfone was then removed by electrolysis 26 to afford triamine 112. Reaction of 112 with thiophosgene, followed by activation with methyl

iodide and treatment with Hunig's base afforded bicyclic guanidine 113.

C. Synthesis of Guanidine-Containing Natural Products.

Guanidine-containing natural products usually display interesting biological activity and their challenging structural features turn them into attractive targets for synthetic chemists.

In 1972, Kishi and coworkers reported the total synthesis of the structurally complex puffer fish poison dl-tetrodotoxin (Scheme XXIII ).36 The synthesis started with acetamide 114, which was converted to acetamide 115 by osmium tetroxide oxidation, followed by acetonide formation. The acetamide moiety in compound 115 was cleaved by reaction with triethyloxonium tetrafluoroborate, followed by acidic work-up. The resulting amine was treated successively with cyanogen bromide and hydrogen sulfide, to afford thiourea 116 in nearly quantitative yield. Reaction of compound 116 with triethyloxonium tetrafluoroborate afforded the corresponding S-ethyl isothiourea, which after acetylation and reaction with acetamide, afforded diacetyl-guanidine 117 in 50% yield. Diol 118 was obtained in 60% yield after acetonide cleavage. The diacetylguanidino moiety in 118 was converted to the monoacetylguanidino compound by acidic hydrolysis. Periodic acid oxidation of the diol moiety, followed by hydrolysis of the acetyl groups afforded dl-tetrodotoxin 119 in only 15% yield.

A more direct and efficient route to 119 started with acetamide 114 which was converted to amine 120 in two steps. Treatment of 120 with S,S-diethyl A/-acetyl- iminodithiocarbonimidate afforded diacetyl-guanidine 121. The overall yield for the conversion of 114 to 121 was 20%. Treatment of 121 with ammonia afforded the corresponding monoacetylguanidine which was converted to compound 119 via a three-step sequence. 27 Scheme XXIII. Kishi's Total Synthesis of dl*Tetrodotoxln 119

CH2OAc CH2OAc CH2OAc OAc 'OAc vOAc c- d, e < * A c HN m AcHNi* #/H ' H2Nv NHi *

O 115 (70%) 116 (93%)

C, g ,h

kCHjOAc 'OAc

AcHN

119 (15%) 118 (60%) 117 (50%) dl-Tetrodotoxin

AcHN

1 2 0 121 (20%) (25%)

(a) OSO4, pyridine, THF; (b) acetonide formation; (c) EtsOBF,!, CH 2CI2; (d) HOAc; (e) CNBr, NaHCQj; (f) H 2S; (g) AC2O, pyridine; (h) ACNH 2; (i) BF3, TFA, CH2CI2; 0) TFA; (k) HI0 4 ,H20 , MeOH; (I) NH 4OH, MeOH; (m) NH3l CH 2CI2, MeOH.

In 1977, Kishi and coworkers reported the total synthesis of the paralytic shellfish poison dl-saxitoxin (Scheme XXIV ).37 The synthesis started by converting lactam 122 to vinylogous carbamate 123 by a three-step sequence, namely thiolactam formation followed by 28 Scheme XXIV. Kishi's Total Synthesis of dl-Saxitoxin 130

COOMe MeO a, b,c d, e HN ■ 6 0

122 123 50% 124 (75%)

f, g. h, i

CH-PBn NH NH HN * NH ^ l,m HN■v T > ss0 i.k

127 (33%) 126 (32%) 125 (75%)

n, o

NAc NAc NH AcN HN NAc p.q AcN HN /NH HN‘^ N ' V nh

128 (75%) 129 (30%) 130 (50%) DL-Saxitoxin

(a) P4S10, CeHe; (b) CH 3COCH(Br)COOCH3> NaHC03> CH2CI2; (c) KOH, CH3OH; (d) BnOCH 2CHO, Si(NCS)4l C6H6; (e) 110°C, PhCH3; (f) NH 2NH2.H20, MeOH; (g) NOCI, CH2CI2; (h) 90°C, CeHe; (i) NH3, C 6H6; 0) HSCH2CH2CH2SH, BF3.OEt2lCH3CN; (k) HOAc, TFA; (I) Et3OBF4, NaHCOs, CH2CI2; (m) EtC02NH4; (n) BCI3, CH 2CI2; (o) Ac20 , pyridine; (p) NBS, H 20, CH3CN; (q) 100°C, MeOH; (r) CIS0 2NCO, HCOOH. 29 sulfide contraction and decarboxylation. Compound 123 was condensed with benzyloxyacetaldehyde and silicon tetraisothiocyanate to afford thiourea 125 in 75% yield.

Transformation of the ester moiety in compound 124 to the corresponding urea was accomplished via a four-step sequence to afford compound 125 in 75% yield. Reaction of compound 125 with 1,3-propanedithiol and boron trifluoride etherate afforded the corresponding thioketal, which was cyclized under acidic conditions to afford compound 126 as a single isomer in a 32% overall yield. Compound 126 was a suitable precursor for guanidine formation, which was accomplished by reaction with triethyloxonium tetrafluoroborate, followed by treatment with ammonium propanoate, to afford diguanidine 127 in 33% yield. The subsequent use of boron trichloride allowed for the deprotection of the benzyl ether, and the reaction product was peracetylated to afford hexaacetate 128. The thioketal and acetyl protecting groups were removed using N-bromosuccinimide, followed by methanolysis to afford compound 129 in 30% yield. Finally, reaction of 129 with chlorosulfonyl isocyanate afforded dl-saxitoxin 130 in 50% yield.

Another synthesis of saxitoxin was reported by Jacobi and coworkers in 1984.38 As shown in Scheme XXV, the synthesis started with the hydrazide derivative 131. One of the key steps of the synthesis involved treatment of 131 with methyl glyoxylate hemiacetal in the presence of boron trifluoride etherate. Under these conditions, compound 131 was converted to the azomethine imine intermediate, which underwent a kinetically controlled 1,3-dipolar cycloaddition to afford pyrazolidine 132 in good yield. The ester moiety was then epimerized by equilibration with sodium methoxide in methanol, and the resulting ester was reduced with sodium borohydride to afford alcohol 133. Under transfer hydrogenation conditions, compound 133 was debenzylated and the resulting amine was subsequently acylated with phenyl chlorothionoformate to afford pyrazolidine 135 in 80% overall yield. The second key step of the synthesis, namely pyrazolidine ring cleavage followed by intramolecular acylation, was accomplished by treating 135 with sodium in ammonia. Compound 136 was isolated in

75% yield. Reaction of thiourea 136 with acetic anhydride, followed by treatment with triethyloxonium tetrafluoroborate afforded bis(pseudourea) 137 in quantitative yield. Reaction 30 Scheme XXV. Jacobi's Synthesis of Saxitoxin

H / Ph COOMe N H -N h H I u =

>=< Nj l ) = ° a ',N_V S ~ Ph b ,c ' Pk

H ?• - 9 u

131 >32,65-75%,

OH / ^ OH .OH S H H. y — N H H- JL fi H H- A yN“YT>*s g 0Ph . *.* j”V V 'Ph

sC 7 C / C /

136 (75%) 135 (80%) 134 (98%)

h,i

OAc OAc / / H ''---- a . H ) _ N/ Ac H\ - , / ^ N Acv - / " - N ' \ l K _ y « * > k i X - } * NAc HC? " o 137 (100%) 128 (48%)

(a) MeOCH(OH)COOMe, BF 3*0Et2, CH3CN; (b) NaOMe, MeOH; (c) NaBH4, MeOH; (d) BH 3*DMS, BF3»OEt2, THF; (e) Pd black, HCOOH, HOAc; (f) PhOCSCI, pyridine, THF; (g) Na/NH3; (h) Ac 20, pyridine; (i) Et 3 0 BF4, NaHC03, CH2CI2; (j) EtC02NH4; (k) Ac20 , pyridine. 31 with ammonium propanoate followed by peracetylation afforded hexaacetate 128, which had formerly been synthesized by Kishi .37 Compound 128 was subsequently converted to saxitoxin 130 by Kishi's procedure.

In 1984, total syntheses of (±)- and (-)-ptilocaulin were reported by Snider and coworkers (Scheme XXVI) 39 Alkylation of p-ketoester 138 with crotonaldehyde afforded the corresponding disubstituted p-ketoester, which underwent aldol condensation, hydrolysis and decarboxylation under acidic conditions. Cyclohexenone 139 was isolated in a 48% overall yield as a 63:37 mixture of diastereomers. Subsequent 1,4-addition of Grignard reagent 140 afforded cyclohexanone 141 in 63% yield. Acetal hydrolysis and cyclization to compound 142 were accomplished by treatment of 141 with dilute hydrochloric acid. Condensation with guanidine followed by treatment with dilute nitric acid afforded (±)-ptilocaulin nitrate 143 in 37% yield.

The synthesis of (-)-ptilocaulin started with cyclohexenone 144 (Scheme XXVI).

Alkylation with crotyl bromide afforded cyclohexenone 145 as a 4:1 mixture of diastereomers.

Compound 146 was obtained after 1,4-addition of Grignard reagent 140. The double bond was hydrogenated, and subsequent acid-catalyzed acetaf hydrolysis followed by annelation afforded diastereomers 148 and 149, which were separated by column chromatography.

Compounds 148 and 149 were independently converted to (-)-ptilocaulin nitrate 150 in a 40% yield, using the conditions described for the racemic series.

In 1985, Roush and coworkers reported another total synthesis of (-)-ptilocaulin

(Scheme XXVII ).40 Starting from cyclohexenone 151 as a 6:1 mixture of diastereomers, 1,4- addition of allyltrimethylsilane afforded cyclohexanone 152 in 95% yield. Enol phosphate 153 was obtained after kinetic enolate formation from 152 and subsequent trapping with chlorodiethylphosphate. The external olefin in 153 was converted to the primary alcohol via hydroboration-oxidation, and the resulting enol phosphate was reduced with lithium in ethylamine to afford alcohol 154 in 90% overall yield. Oxidation with pyridinium chlorochromate afforded aldehyde 155. Reaction of compound 155 with benzylhydroxylamine afforded the intermediate nitrone which underwent 1,3-dipolar addition to yield 80% of isoxazolidine 158 as 32 Scheme XXVI. Snider's Total Synthesis of (±)- and (-)-Ptilocaulin

o o /—•O O y—- MgBr Me' a, b, c

* ■O

1 3 8 139 {48%) 1 4 0 a-Bu: 63% p-Bu: 37% d

N° 3 - +NH2 x

Me x . Me H

143 (37%) 1 42 (63%) 141 (63%) (±)-Ptllocaulin

O BrMg

h. i

6 , Me x d /

1 4 4 145 (60%) 1 4 0 1 46 (61%) a-Bu: 20% P-Bu: 80% j

HN NH

Me X

150 (40%) 1 48 a-Bu (24%) 147 (99% ) (-)-Ptilocaulin 149 p-Bu (33%)

(a) NaOMe, MeOH; (b) crotonaldehyde; (c) HCI, HOAc; (d) CuBr.Me 2S, THF; (e) 0.5N HCI, DME; (I) guanidine, C 6H6; (g) 1% HN03; (h) LDA, THF; (i) crotyl bromide, HMPA; 0) Pd/C, EtOH, 10 psi H 2. 33 Scheme XXVII. Roush's Total Synthesis of (-)-Ptilocaulin

b, c

■v. Me Me Me

151 152 (95%) 153 (77%)

d, e, f Ph L t a r - c a r

156 (80%) 155 (90%) 154 (90%)

i. j.k ,N 0 2 N 2 t JI n o 3- + H2N ^ N ' Nvv z [ y— Me HN NH H t a r

157 (90%) 150 (58-65%) (-)-Ptilocaulln

(a) Allyltrimethylsilane, TiCI4, CH 2CI2; (b) LDA, HMPA, THF; (c) CIPO(OEt)2; (d) 9-BBN, THF; (e) H 20 2, NaOH; (f) Li-EtNH2, FBuOH; (g) PCC, NaOAc, CH2CI2; (h) PhCH 2NHOH, C6H6l 3A sieves; (i) Zn, 10M AcOH; (j) Cr0 3-H2S04, HOAc, HCI; (k) Pd black, HCOOH, CH 3OH; (I) 145-155°C.

a separable mixture of diastereomers. Compound 156 was converted to amino-ketone 157 by a three-step sequence. Subsequent condensation of compound 157 with guanyl-1,3- dimethylpyrazole afforded (-)-ptilocaulin 150 in 58-65% yield. 34 Two other syntheses of (±)-ptilocaulin were reported in the literature .41 - 42 Both led to the preparation of enone 142, first synthesized by Snider.

As shown in this chapter, a wide array of methods for the introduction of a guanidine moiety are available in the literature. Our plan was to incorporate the most suitable methodology in our synthesis of analogs 14,15 and 16. Our results are described in the following chapters.

However, the synthesis of the amido-alcohol portion of ptilomycalin A will first be presented in the next chapter. CHAPTER III

SYNTHESIS OF THE AMIDO-ALCOHOL PORTION

OF PTILOMYCALIN A

A. Retrosynthetic Analysis.

Our first objective was to synthesize the amido-alcohol portion of ptilomycalin A (158).

Moreover, to secure the proposed structure of ptilomycalin A, we decided to synthesize compound 7 and compare its spectral data to those published by Kashman and coworkers, as 7 was isolated after degradation of the bis(trifluoroacetamide) derivative of ptilomycalin A .1 This would confirm the structure assignment for the anchor portion of ptilomycalin A.

Retrosynthetically, it was hoped that compound 158 could be obtained by coupling carboxylic acid 159 and spermidine derivative 160 (Scheme XXVIII). According to a literature methodology, compound 159 was to be prepared from propargyl alcohol .43 Amine 160 was to arise from the selective protection of the two primary amino groups in spermidine (160 where R

= H).

B. Synthesis of the Amido-Alcohol Portion of Ptilomycalin A.

In 1988, Apparu and coworkers reported the synthesis of nitrite 165, which appeared to be a suitable precursor for the synthesis of a carboxylic acid of type 159 43 Thus, this

35 36 Scheme XXVIII. Retrosynthetic Analysis of Compounds 158 and 7

158 FT = H 7 R = COCF3, R' = Ac

R I I N>,

*COOH +

15 9 ‘N I H 1 6 0

HOCHz— H

161

research began by repeating the synthesis of 165 as shown in Scheme XXIX.

Propargyl alcohol 161 was converted to its tetrahydropyranyl ether 162 in 75% yield.

Subsequent alkylation of acetylene 162 with 1,12-dibromododecane afforded bromide 163 in

48% yield. Hydrogenation of 163 using platinum oxide as the catalyst afforded bromide 164 in

96% yield. Nitrile 165 was obtained in 86 % yield after treatment of bromide 164 with sodium cyanide under phase-transfer conditions. The nitrile moiety was subsequently hydrolyzed, using 10 M aqueous sodium hydroxide in methanol at reflux, to afford carboxylic acid 166 in

95% yield. Compound 166 was a suitable precursor for coupling with a spermidine derivative. 37 Scheme XXIX. Synthesis of Carboxylic Acid 166

HOCHg H ------— ► THPOCHg— = = — H — - ■’— »> THPOCH2 — = ~ — (CH2),2Br

161 162 (75%) 163(48% )

f e THPO— (CH2)15COOH ------THPO— (CH2)15CN ------THPO— (CH2)15Br

166 (95%) 165 ( 86 %) 164 (96%)

(a) Dihydropyran, cat. HCI; (b) n-BuLi, THF, -78°C; (c) Br(CH 2)i2Br, HMPA, THF (d) H2, cat. R 0 2 , EtOAc; (e) NaCN, cat. n -Bu3N, A; (f) NaOH, MeOH, A.

Scheme XXX. Fujita's Synthesis of Spermidine Derivative 169

O g .N H , r N-„

167 1 6 8 169 (79%)

The diprotection of spermidine required selective protection of the two primary amino groups in the presence of a secondary one. In 1986, Overman reported that such a transformation could be accomplished by reaction with fert-butyldiphenylsilyl chloride and triethylamine in acetonitrile at room temperature. Under these conditions, primary amines were silylated but secondary amino groups did not react .44 Application of this methodology to the 38 protection of spermidine, however, afforded a mixture of products which could not be separated by column chromatography over silica gel. In 1980, however, Fujita and coworkers reported that reaction of two equivalents of 3-acylthiazolidine-2-thione 167 with one equivalent of spermidine (168) afforded spermidine derivative 169 in 79% yield (Scheme XXX ).45 It was decided to apply this methodology to the synthesis of the bis(carboxybenzyl) spermidine derivative 172, which would meet our requirements for a compound of type 160 (Scheme

XXXI). Reaction of thiazolidine-2-thione 170 with benzyl chloroformate and triethylamine afforded 3-acylthiazolidine-2-thione 171 in 85% yield .45 Subsequent reaction of two equivalents of 171 with one equivalent of spermidine 168 afforded the diprotected spermidine derivative 172 in 52% yield.

Scheme XXXI. Synthesis of Spermidine Derivative 172

s O s H a + PhCHp ’ k / s

1 7 0 171 (8 6 %) 1 6 8

o. ,OCH2Ph Y

172 (52%)

(a) PhCH 2OCOCI, Et3N, THF, 50°C; (b) CH 2CI2. 39 Scheme XXXII. Synthesis of Amldo-Alcohol 174

THPO— (CH2)15COOH

1 6 6 O ^ , 0 CH2Ph

O^OCHgPh N„ . / ' , N A, OCH2Ph THPO~ f T r N- I O 14 o H

N.A. OCHoPh i 173 (95%) H

1 7 2

0*. .OCH2Ph

N OCH2Ph

174 (87%)

(a) DCC, HOBt, THF; (b) acidic Dowex-50, MeOH.

The coupling of carboxylic acid 166 with amine 173 was initially accomplished using dicyclohexylcarbodiimide in the presence of a catalytic amount of 4-dimethylaminopyridine .47

However, the yield of amide 173 was only 57%. When 1-hydroxybenzotriazole was substituted for 4-dimethylaminopyridine, amide 173 was isolated in 95% yield (Scheme XXXII ).48 The final transformation in the synthesis of a compound of type 158 was the hydrolysis of the tetrahydropyranyl ether. This was accomplished using acidic Dowex-50 resin in methanol to afford amido-alcohol 174 in 87% yield. 40 C. Synthesis of Acetate 7.

Amide 173 was converted to acetate 7 using the reaction sequence shown in Scheme

XXXIII. Attempted hydrogenolysis of the carboxybenzyl protecting groups in 173 using palladium on carbon as the catalyst was unsuccessful, possibly because of catalyst poisoning .49

However, both benzyl carbamates were cleaved when the hydrogenolysis was conducted in the presence of palladium hydroxide on carbon as the catalyst .50 The resulting diamine was not

Scheme XXXIII. Synthesis of Acetate 7 from Amide 173

° Y ° CH2Ph

a, b

THpO 'X ^ \ / l',> s ^ \ / ^ N^ o c H 2Ph THPO J L H H 173 175(65%)

° Y ° F3

•N> .N. H

O x *N------CF, A* ’ ~ f £ Y N' I 3 14 o 14 o H 7 (70%) 176 (100%)

(a) H2, cat. Pd(OH)2/C, EtOH; (b) (CF 3C0)20, pyridine, CH 2CI2; (c) acidic Dowex-50, MeOH; (d) Ac 20 , pyridine, 4-DMAP, CH 2CI2. 41 isolated, but directly converted to bis(trifluoroacetamide) 175 by reaction with trifluoroacetic anhydride and pyridine in dichloromethane .51 The overall yield of compound 175 was 65%.

The tetrahydropyranyl ether moiety in 175 was hydrolyzed as above to afford alcohol 176 in quantitative yield. Finally, acetylation of compound 176 afforded acetate 7 in 70% yield .52 The

1H NMR spectrum of 7 was identical to the one reported by Kashman and coworkers .1

In summary, the amido-alcohol portion of ptilomycalin A was synthesized from two building blocks in 85% yield. Moreover, the structure of the anchor portion of ptilomycalin A was confirmed by preparing acetate 7. The next chapter will present the synthesis of guanidine 14, a simple analog of ptilomycalin A. CHAPTER IV

SYNTHESIS OF A SIMPLE STRUCTURAL

ANALOG OF PTILOMYCALIN A

A. Introduction

Our second objective was to synthesize ptilomycalin A analog 14 depicted in Figure 8 .

Compound 14 is a simple structural analog of ptilomycalin A, having a bicyclic guanidine as the vessel subunit, which is attached via an ester linkage to the amido-alcohol subunit of ptilomycalin A. As shown in Scheme XXXIV, we envisioned that compound 14 would arise from ester bond formation between a bicyclic guanidine of type 177 (R, R' = H, protecting group), and amido-alcohol 174. In this chapter, three unsuccessful approaches to bicyclic guanidine

177 will be discussed, as well as a successful synthesis of compound 14.

B. Attempted Synthesis of Guanidine 177 via an Intermediate Monocyclic

Guanidine.

Our first approach to guanidine 177 was based on the synthesis of a monocyclic guanidine of type 178 (Scheme XXXV). According to Mackay and coworkers (Scheme VIII), compound 178 could potentially be converted to a bicyclic guanidine of type 177 via an intramolecular N-alkylation. 22c Monocyclic guanidine 177 was to be prepared by the

42 43 Scheme XXXIV. Retrosynthetic Analysis of Analog 14.

O 1 4

0^ ,O C H zPh

o a N x ' c r i, HO- N^^O CH2Ph R R' I 14 o H 17 7 1 7 4

Scheme XXXV. First Retrosynthetic Analysis of Guanidine 177

COOEt

NH, C C T = > L.A..J r V r = > HO T i-V 1 7 9 A 177 178 +

COOEt COOEt

Br- x X -COOEt rS rS > R/N y NH r^ ^ nh O r SMe

18 2 181 1 8 0 44 condensation of propanolamine 179 with an S-methyl isothiouronium salt of type 180.

Compound 180 was in turn to arise from a cyclic urea of type 181, which was to be prepared from ethyl 2-bromomethylacrylate 182.

Scheme XXXVI. Synthesis of Ethyl 2-Bromomethylacrylate 182

a_ H ° ^ < 5 0 2Et b Br^ . Et02Cx'^C02Et ------► X V-COOH HO— ' COzEt Be—'

1 8 3 184 (97%) 185(51% )

Br~ \ d Br" \ COOEt - • ------^ J — COOEt

182 ( 8 8 %) 186 (80%)

(a) 37% aq. HCHO, K2C03; (b) 48% HBr, A; (c) cat. H 2S04l EtOH, C6H6; (d) Et3N, C6H6.

Ethyl 2-bromomethylacrylate 182 was prepared according to literature procedures

(Scheme XXXVI). Diethyl malonate was converted to diester 184 in 97% yield .53 Conversion of

184 to carboxylic acid 185 was accomplished with concentrated hydrobromic acid at reflux .54

Compound 185 was esterified according to the procedure of Ferris to afford ethyl ester 186 in

80% yield .55 Finally, treatment of 186 with triethylamine afforded compound 182 in 88 % yield .5 4 ,55

An attempted synthesis of a monocyclic urea of type 178 from unsaturated ester 182 is shown in Scheme XXXVII. Ethyl 2-bromomethylacrylate 182 was treated with three equivalents of benzylamine to afford diamine 187 in 73% yield, resulting from Sn 2' displacement of the bromide followed by 1,4-addition. The intermediate product could not be isolated, nor could it be detected by thin-layer chromatography. Cyclization to dibenzylurea 45 188 was accomplished by treating 187 with carbonyldiimidazoie .56 Attempts to cleave both benzyl protecting groups by hydrogenolysis of 188 in ethanol or acetic acid in the presence of palladium on carbon were unsuccessful. Treatment of 188 with sodium in ammonia also failed to remove the benzyl groups. Field and coworkers had reported that a similar deprotection could be accomplished using concentrated hydrobromic acid in their total synthesis of biotin .57

When dibenzylurea 188 was subjected to these conditions, however, the only detectable product after esterification of the crude product with ethanol was the monobenzylurea 189 isolated in 60% yield. To test the

Scheme XXXVII. Attempted Synthesis of Monocyclic Guanidine 178

COOEt COOEt I Br^ , a A— COOEt ► A - 5 _ rS // 1I I Ph. N N N N . .Ph ' Ph^^NHMU HN^^Ph Ukl Dh ^ Y ^ O

1 8 2 187 (73%) 188 (73%)

c, d

COOEt COOEt COOEt

f l f r^i e Ph>^+YNH ^ Ph^N NH P^vNyNH I" SMe !J J

191 (85%) 190 (82%) 189 (60%)

h2nx ’v > ^ n*oh EtOH, A

No isolable product J

(a) PhCH 2NH2, CHCI3; (b) (lm) 2CO, C6H6; (c) 48% HBr, A; (d) EtOH, A; (e) Lawesson’s reagent, PhCH3; (f) Mel, MeOH. 46 proposed strategy, urea 189 was converted to thiourea 190 in 82% yield by treatment with

Lawesson's reagent.58* 59 Reaction with methyl iodide afforded S-methyl isothiouronium iodide 19 1 22c Upon treatment of compound 191 with propanolamine according to Mackay's procedure, evolution of methyl mercaptan took place, suggesting that guanidine formation had occurred .220 However, the purification procedure called for filtration over a basic Dowex resin, under which conditions ester hydrolysis took place. The possibility of concommitent amide formation or transesterification between propanolamine and the ester moiety could also not be ruled out. The synthesis was therefore redesigned.

C. Attempted Synthesis of Guanidine 177 via an Intermediate Monocyclic

Urea.

The second approach that was considered is outlined in Scheme XXXVIII. It was hoped that guanidine 177 could be prepared from thiourea 192, which would be derived from urea

Scheme XXXVIII. Retrosynthesls of Guanidine 177 via a Monocyclic Urea

COOEt

COOH COOEt

1 7 7 1 9 2 1 93

COOEt

o HO OH 1 8 2 1 95 1 9 4 47 193. Compound 193 was to be prepared by either N-alkylation of urea 194 or desymmetrization of diol 195. Compounds 194 and 195 were to be prepared from 182.

The N-methylation of a monobenzyl urea had been reported by Field .60 As shown in

Scheme XXXIX, reaction of biotin derivative 196 with sodium in ammonia afforded benzylurea

197, which was alkylated with methyl iodide to afford urea 198. Compound 198 was subsequently converted to methylbiotin. This sequence served as a precedent for routes passing through intermediates of type 194.

Scheme XXXIX. Field's Preparation of Urea 198

o .A . ^ A Me Ph wn Ph N N H OH ,OMe

H 1 9 6 1 9 7 1 9 8

(a) Na/NH3; (b) Mel, NaH, DMF.

With urea 188 already in hand (Scheme XXXVII), we first turned our attention to the synthesis of a compound of type 194 as shown in Scheme XL. The ester moiety in 188 was reduced with sodium borohydride in methanol to afford alcohol 199 in 86 % yield .61 The hydroxyl group in 199 was then protected to afford ferf-butyldimethylsilyl ether 200 .62

Attempted cleavage of one benzyl group by reaction with sodium in ammonia met with failure, affording a mixture of products .61 Crude 1H NMR analysis showed that partial hydrolysis of the silyl protecting group had occurred.

The hydroxyl protecting group was therefore replaced with the more stable tert- butyldiphenylsilyl group, as shown in Scheme XLI .63 Treatment of compound 201 with sodium in ammonia afforded 61% of urea 202, along with unreacted starting material .61 The required three-carbon alkylating agent 204 was prepared from 3-benzyloxy-1 -propanol 203.64>65 Initial 48 Scheme XL. Synthesis and Attempted Deprotection of Urea 200

COOEt CH2OH CHjOTBDMS * * ' NV ^ N- ' Ph Ph^ " Nvjj^rS Nv^ Ph Ph^ ^Ph n Yn o O o

1 8 8 199 (86%) 200 (87%)

(a) NaBH4, MeOH; (b) TBDMSCI, imidazole, DMF; (c) Na/NH3.

No clean deprotection )

Scheme XLI. Synthesis and Attempted N-Alkylatlon of Urea 202

c h 2o h CH2OTBDPS CHjOTBDPS

Nw ^Ph * * X Phv NY NV X Ph Ph^ NvY ^ NH o o o

1 9 9 201 (72%) 202 (61%)

BnO OH BnO ‘ Br BnO '— "*l

2 0 3 204 (45%) 205 (90%)

CHgOTBDPS

e, f No alkylation Ph^ ,NH Y 1 o 202

(a) TBDPSCI, imidazole, DMF; (b) Na/NH3, THF; (c) Ph 3P, NBS; (d) Nal, acetone; (e) NaH, DMF; (f) 204 or 205. 49 attempts to alkylate urea 202 with bromide 204 under the conditions described by Field were unsuccessful. The reaction of iodide 205 under similar conditions also met with failure.

However, crude 1H NMR analysis showed that both 204 and 205 had undergone elimination under the reaction conditions, a process which precluded alkylation. At this point, this approach did not seem promising, and we turned our attention to the synthesis of diol 195.

Scheme XLII. p-Ellmination of Acrolein

COOEt COOEt COOEt * rS _ rS .N NH T / \ * / T \ ■ o HO OH O X 1 9 5 2 0 6 2 0 7

1. 0 3 2. EfeN R C O j , ^ ^ 5^ ► RCOfeH

2 0 8 2 0 9

This approach was based on the assumption that compound 195 could be converted to a disymmetric urea of type 206. Aldehyde 206 could potentially undergo a p-elimination process when treated with base to liberate acrolein and yield a urea of type 207 (Scheme XLII).

A related transformation had been reported in the literature, as 3-butenyl esters of type 208 were converted to carboxylic acids 209 by ozonolysis followed by treatment with triethylamine .66

Cyclic urea 195 was prepared as shown in Scheme XLIII. Protection of the hydroxyl group in propanolamine 179 was accomplished via a two-step sequence. Reaction of propanolamine with two equivalents each of fert-butyldimethylsilyl chloride and DBU 67 afforded an intermediate N, O-diprotected compound, which was reacted with acidic Dowex-50 resin at

0°C to afford amine 210 in 92% overall yield. Reaction of three equivalents of 210 with ethyl 2- 50 bromomethylacrylate 182 afforded diamine 211 in 73% yield. Again, no 1:1 adduct derived from acrylate 182 and amine 210 was detectable. Cyclic urea 212 was obtained in 58% yield upon treatment of 211 with carbonyldiimidazole .56 Subsequent cleavage of the silyl ethers with acidic Dowex-50 resin in methanol afforded diol 195 in 85% yield.

Scheme XLIII. Preparation of Urea 195

a,b H2tr ^OTBDMS

210 (92%)

COOEt

COOEt > TBDMSO, NH HN OTBDMS

18 2 211 (73%)

COOEt

TBDMSO, OTBDMS

195 (84%) 212 (58%)

(a) TBDMSCI, DBU, C6H6; (b) acidic Dowex-50, MeOH, 0°C; (c) 210, CHCI3; (d) (lm)2CO, C6H6: (e) acidic Dowex-50, MeOH.

The desymmetrization of 195 could be accomplished by two different reagents, as shown in Scheme XLIV. Treatment of diol 195 with two equivalents of methoxymethyl chloride and Hunig's base afforded 48% of monoprotected alcohol 214 along with 32% of diprotected product 213 and 12% of starting material .68 When 195 was treated with dihydropyran and a catalytic amount of pyridinium p-toluenesulfonate, compound 216 was obtained in 49% yield 51 along with 35% of diprotected product 215 and 8 % of starting material .69 The latter transformation was preferred as diprotected compound 215 could be hydrolyzed more easily than compound 213 for the recycling of diol 195.

Scheme XLIV. Desymmetrizatlon of Diol 195

COOEt COOEt COOEt

HO OH MOMO OMOM HO OMOM 1 9 5 213 (32%) 214 (48%)

COOEt COOEt COOEt

HOOH THPO OTHP HO OTHP 1 9 5 215 (35%) 216 (49%)

(a) MOMCI, EtN(/-Pr)2, CH2CI2; (b) dihydropyran, PPTS, CH 2CI2.

The next transformation to be addressed, prior to the oxidation-p-elimination sequence, was the conversion of the hydroxyl moiety into a protected amine. As shown in Scheme XLV, reaction of alcohol 216 under Mitsunobu conditions with the amine equivalent 217 afforded compound 219 in 78% yield.70- 71 The tetrahydropyranyl ether in 218 was then hydrolyzed to afford alcohol 219 in 89% yield. 52 Scheme XLV. Preparation of Alcohol 219

COOEt COOEt COOEt

S E S ' "BOC * 2 1 7 rS - / Y \ /A HO OTHP .N . OTHP OH SES BOC SES' BOC

2 1 6 218 (78%) 219 (89%)

(a) PhaP, DEAD, THF; (b) acidic Dowex-50, MeOH.

Scheme XLVI. Attempted Three-Carbon Unit Elimination

rS * /A SESX ''’BOC SESX "BOC 2 1 9 220 (84%) b-d \ COOEt CO * /Y\ i t rV”

S E S '' "BOC SES*' "BOC 222 (52%) 221

(a) (COCI)2, DMSO, Et3N, CH2CI2; (b) o-N0 2C6H4SeCN, n-Bu 3P, THF; (c) Na2HP04; (d) 30%H2O2. 53 Alcohol 219 was a suitable precursor for the oxidation-p-elimination sequence. Swern oxidation of 219 proceeded smoothly to afford aldehyde 220 in 84% yield (Scheme XLVi ).72

However, treatment of 220 with DBU in chloroform or with potassium fe/f-butoxide in tert- butanol did not accomplish the expected (3-elimination to urea 221. Rather, 1H NMR analysis of the crude reaction mixture indicated that an aldol condensation had occured. This result could be attributed to an unexpected poor leaving-group ability of the urea moiety. Nevertheless, compound 221 could also potentially arise from allyl urea 2 2 2 after olefin isomerization followed by hydrolysis of the resulting /V-vinyl urea. Therefore, compound 222 was prepared in

52% yield by selenenylation-oxidation of alcohol 219.73 We next attempted to isomerize the olefin moiety in 222. This transformation is closely related to the deprotection of allylic esters, carbonates and carbamates, which is usually accomplished by catalysis with palladium ( 0) species. Selected examples from the literature are shown in Scheme XLVII. Allyl carbamate

223 was converted to amino acid 224 by treatment with a catalytic amount of a palladium (0) species in the presence of triphenylphosphine and 2-ethylhexanoic acid .74 Allyl carbamate

225, when treated with a trialkylsilane, palladium acetate and triethylamine, afforded silylamine

226 in quantitative yield .75 Deprotection of the allyl carbamate of proline 227 was effected by reaction with a palladium (II) species in the presence of tributyltin hydride and triethylamine 76

Deprotection of nucleoside 22 9 was accomplished by reaction with tetrakis(triphenylphosphine)palladium (0), triphenylphosphine and formic acid to afford 230 in quantitative yield 77 Treatment of carbapenem 231 with tetrakis(triphenylphosphine) palladium

(0) and triphenylphosphine in the presence of pyrrolidine afforded compound 232 in 93% yield .78 Moreover, lithium dimethyl cuprate proved effective for the cleavage of allyl esters .79

When compound 222 was submitted to the conditions shown in Scheme XLVII, no reaction occurred in any case. The lack of reactivity of the allyl moiety in 222 could be attributed again to the poor leaving group ability of the urea moiety, or the lack of driving force, that is evolution of carbon dioxide. 54 Scheme XLVII. Allyl Moiety Cleavage

o Pd(PPh3)4, PPh3 2-ethylhexanoic acid HOOC NH, h o2c ' ► I H 2 2 3 224 (89%) o TBDMSH, Pd(OAc)2 -TBDMS E ^C H A i HN Y C02Me Y C02Me 2 2 5 226 (100%)

Pd(PPh3)2CI2 n-BWjSiH U AcOH, CH2CI2 HN—f^ O H ■OH o 2 2 7 228 ( 100%) O

H N ^ O NH.

Pd(PPh3)4, PPh3 MMTrO, MMTrO. HCOOH, THF

OTBDMS OTBDMS 2 2 9 230 (100%)

H I Pd(Ph3)4,PPh3 Ph Pynrolidine, THF

COOH 231 232 (93%)

Me2CuLi Etp RCOO RCOOH

2 3 3 234 (75-85%) 55 Further inspection of the literature revealed that the isomerization of allyl ureas was a

known transformation that had been reported by Marquet and coworkers. As shown in Scheme

XLViil, treatment of diallyl urea 235 with a catalytic amount of rhodium trichloride trihydrate

afforded isomerized urea 236 in 94% yield .80 Moreover, biotin precursor 237 was converted to urea 238 when reacted with a catalytic amount of Wilkinson’s catalyst .81 However, when compound 222 was submitted to the same reaction conditions, no reaction occurred.

Scheme XLVlll. Marquet’s Allyl Urea Isomerization and Cleavage

O RhCl3.3Hp O

^ A ~ ^ V_V \—/

235 236 (94%)

^ ~ A ^ » T O ' hnAHN NH mH H")—("H Hf '/X

h o 2 c ' 2 3 7 238 (>40%)

The conversion of the urea into a thiourea was then investigated. It was anticipated that a thiourea moiety would be a better leaving group than a urea, because of its greater zwitterionic character. Aldehyde 220 was therefore converted to acetal 239 in 75% yield by reaction with ethylene glycol in the presence of a catalytic amount of pyridinium p-toluenesulfonate (Scheme

XLIX).82 However, when acetal 239 was heated with Lawesson's reagent in toluene, decomposition occured. Reaction of urea 212 with Lawesson's reagent in toluene at reflux also afforded decomposition products. Diol 195 was therefore converted to diacetate 240 in

96% yield by reaction with acetic anhydride, triethylamine and a catalytic amount of 4- dimethylaminopyridine .83 When urea 240 was reacted with Lawesson's reagent, no reaction occured (Scheme XLIX). A new route to guanidine 177 was therefore investigated. 56 Scheme XLIX. Attempted Thiourea Synthesis

COOEt COOEt

Decomposition

2 2 0 239 (75%)

COOEt COOEt

b No reaction

HO OH AcO OAc 1 9 5 240 (96%)

(a) HOCH2CH2OH, PPTS, C6H6; (b) Lawesson's reagent; (c) Ac 20, Et3N, 4-DMAP, CH2CI2.

D. Attempted Synthesis of Guanidine 177 via an Intermediate Acyclic Triamine

The next approach was based on a strategy similar to the one discussed in Chapter II for the synthesis of bicyclic guanidines, namely the synthesis of an acyclic triamine subsequently cyclized onto a one-carbon synthon. It was anticipated that triamine 241 would arise from diol242 after desymmetrization, followed by three-carbon unit elimination, as discussed above.

Diol 242 was to be prepared from diamine 211 (Scheme L).

Diol 242 was synthesized according to the reaction sequence shown in Scheme LI.

Reaction of diamine 211 (Scheme XLIII) with benzyl chloroformate and triethylamine afforded compound 243 in 78% yield .46 Deprotection of the hydroxyl groups with tetrabutylammonium fluoride afforded diol 242 in 75% yield .62 57 Scheme L. Retrosynthetic Analysis of Guanidine 177 via an Acyclic Triamine

CN + fN T = > * I III I ci" » SES CBZ COjEtCBZ R R‘ 1 7 7 24 1

OTBDMS OTBDMS OH OH ( ^ « = t b H C02Et H CBZ COzEt CBZ

21 1 2 4 2

Scheme LI. Synthesis of Diol 242

OTBDMS OTBDMS OTBDMS OTBDMS OH OH

i ^ V ^ ? H C02Et H CBZ C 02Et CBZ CBZ C 02Et CBZ

211 243 (78%) 242 (75%)

(a) CBZCI, Et3N, THF; (b) n-Bu 4NF, THF.

Desymmetrization of diol 242 was accomplished as above by treatment with dihydropyran and a catalytic amount of pyridinium p-toluenesulfonate to afford alcohol 245 in

48% yield along with diprotected derivative 244.69 Reaction of compound 245 with amine equivalent 217 under Mitsunobu conditions afforded compound 246 in 98% yield.70* 71

Hydrolysis of the tetrahydropyranyl ether yielded alcohol 247 in 80% yield (Scheme HI). 58 Scheme Lll. Synthesis of Alcohol 247

OH OH OTHP OTHP OH OTHP

? S S • S S | XSsT ^ i CBZ COzEt CBZ CBZ C02Et CBZ CBZ c ° 2 Et CBZ

242 244 (35%) 245 (48%)

H I .N SES N BOC 2 1 7

BOC. ^SES BOC. X SES N OH N r r OTHF ( ^ ( b CBZ C02Et CBZ CBZ C 02Et CBZ

247 (80%) 246 (98%)

(a) dihydropyran, PPTS, CH 2CI2; (b) Ph 3P, DEAD, THF; (c) acidic Dowex-50, MeOH.

As the ^-elimination of acrolein from urea 220 was unsuccessful, it was decided to investigate the ^-elimination of methyl acrylate from a suitable precursor. Therefore, methyl ester 249 was prepared as shown in Scheme LIU. Oxidation of alcohol 247 with pyridinium dichromate in A/,Aklimethylformamide afforded carboxylic acid 248 in 92% yield .84 Conversion of 248 to methyl ester 249 was accomplished by reaction with dimethylsulphate and potassium carbonate in acetone .85 However, when compound 249 was treated with potassium hydride or lithium diisopropylamide, the only detectable products resulted from Claisen condensation. In addition, compound 251 was prepared in 80% yield from alcohol 248,73 and was submitted to the various reaction conditions shown in Scheme XLVII. However, isomerization could not be accomplished. The synthesis was therefore redesigned. 59 Scheme LIU. Attempted Three-Carbon Unit Elimination from 247

BOC. X SES BOC. ^SES b o o ' n ' SES o h N VN O

hoA j M e O ^ N

C u ' Y ' n - CBZ CQ2Et CBZ CBZ COzEt CBZ CBZ C 02Et CBZ

2 4 7 248 (92%) 249 (63%)

c-e /

BOC. X SES BOC. X SES N N

- t f - c1 ^ NH I CBZ COzEt CBZ CBZ COzEt CBZ

251 (80%) 2 5 0

(a) PDC, DMF; (b) Me 2S04, K2CO3, acetone; (c) o-N 0 2C6H4SeCN, n-Bu 3P, THF; (d) Na2HP04; (e) 30% H 20 2.

E. Synthesis of Guanidine 177 via an Intermediate Acyclic Triamine

In 1993, Barnish and coworkers reported an asymmetric synthesis of p-amino-acid derivatives by Michael addition to 2-amino ethyl acrylates (Scheme LIV ).86 Reaction of terf-butyl

2-bromomethylacrylate 252 with C 2 symmetrical amine 253 in the presence of potassium carbonate afforded acrylate 254 resulting from Sn2' displacement of the bromide in 83% yield.

Subsequent 1,4-addition of the lithium dianion of cyclopentanecarboxylic acid afforded compound 255 in 83% yield. Debenzylation of the amino group was accomplished by hydrogenolysis in the presence of palladium hydroxide on carbon .50 60 Scheme LIV. Asymmetric Synthesis of p-Amlno Acid Derivatives

Ph .M e Me Me " y " COOf-Bu : i BrA _ COOf-Bu + P h ' ^ N Ph I H Me 2 5 2 2 5 3 254 (83%)

CO,H

Ph. .M e COOf-Bu > • coor-Bu HaNV > " k PhY Nv^ j

HOoC Me ✓ ‘" ' X <> ho2c y

256 (95%) 255 (83%)

(a) K2CO3, CH3CN; (b) LDA; (c) 60 psi H2, Pd(OH) 2/C, EtOH.

Scheme LV. Retrosynthesis of Guanidine 177 via a Disymmetric Diamine

CBZ, N * N ^ | ^ N X ‘ Ph OTTCOOH I N + N SES CBZ COOR i a - 1 Ph R R' 1 7 7 2 5 7

'Ph HO 'P h COOR Is, *Ph CBZ COOR ‘ Ph

2 5 9 2 5 8 61 It appeared that this methodology could be applied to the synthesis of a disymmetric

diamine, as shown in the retrosynthetic analysis depicted in Scheme LV. For example, it was

expected that hydrogenolysis of compound 257 would afford a triamine which could be

cyclized onto a one-carbon synthon to afford guanidine 177 (R = SES or H; R’ = H). Compound

257 might be prepared from alcohol 258 by Mitsunobu reaction with an appropriate amine

equivalent. Compound 258 could potentially be obtained by 1,4-addition of a propanolamine

derivative to acrylate 259. Compound 259 was to be prepared from an alkyl 2 -

bromomethylacrylate.

Scheme LVI. Attempted Synthesis of 258 from Acrylate 182

Ph^ BrA a ™ "i COOEt r COOE' — - Mixture

182 260(98%)

(a) (PhCH 2)2NH, K2CQ3, CH3CN; (b) UHNCH 2CH2CH2OTBDMS, THF, -78°C.

As shown in Scheme LVI, addition of one equivalent of dibenzylamine to ethyl 2-

bromomethylacrylate 182 afforded acrylate 260 in 98% yield. When compound 260 was

heated with one equivalent of amine 210, no product resulting from 1,4-addition was detected.

Moreover, reaction of acrylate 260 with one equivalent of the lithium anion of amine 210

afforded a mixture of products resulting from 1,4- and 1,2-addition.

The fert-butyl ester derivative of 260 was anticipated to be a better substrate for 1,4-

addition, as the bulkiness of the fert-butyl group could prevent 1,2-addition from occurring. As

shown in Scheme LVII, reaction of carboxylic acid 185 with isobutylene in the presence of

catalytic acid afforded fert-butyl ester 261 in 74% yield .87 Acrylate 252 was obtained from 261 in 82% yield upon dehydrohalogenation using Hunig's base .87 Reaction of compound 261 with dibenzylamine and potassium carbonate afforded acrylate 262 in 82% yield. When acrylate

262 was reacted at -78°C with the lithium anion of propanolamine derivative 210, amine 263 62 was isolated in 66% yield. The secondary amino group in compound 263 was converted to the benzyl carbamate by treatment with benzyl chloroformate and triethylamine to afford 264 in

84% yield .46 Subsequent cleavage of the silyl ether afforded alcohol 265 in 97% yield .62

Scheme LVll. Synthesis of Alcohol 265

Ph, b ^ “ V c N | COOf-Bu BrA V- COOH COOf-Bu ^ V COOf-Bu Br—S &>B r—f 1 8 5 261 (74%) 252 (82%) 262 (82%)

Ph. Ph. COOf-Bu > COOf-Bu ' I , ph-

.OTBDMS HNn ^ sn ^ otbdms CBZ‘

264 (84%) 263 (6 6 %)

f (a) isobutylene, cat. H 2SO4, C6H6I (b) EtN(/-Pr)2, C 6H6; (c) (PhCH 2)2NH, K2C0 3 , CH3CN; (d) UHNCH2CH2CH2OTBDMS, THF; (e) CBZCI, Et 3N, THF; COOf-Bu (f) o-Bu4NF, THF.

265 97%

The synthesis of a compound of type 257 required the preparation of amine equivalent

269 (Scheme LVIII). First, sulfonamide 267 was prepared from methanesulfonamide (266) in

64% yield .70 Attempted alkylation of the dianion of sulfonamide 267 afforded a mixture of sulfonamides 268 and 269.70 Reaction of the anion of sulfonamide 270 with benzyl chloroformate, however, afforded amine equivalent 269 in 87% yield .70- 88 63 Scheme LVIII. Synthesis of Amine Equivalent 269

0 . .0 a, b,c ! V N n CH3 Ph O '^ N * ' "CH3 I I 3 H H

2 6 6 267 (64%)

d, e A v ° j l v Ph N CH, - Ph TMS + Ph N “TMS I I H H I H TMS 2 6 7 268 (19%) 269 (44%)

f, b, c A HoN TMS Ph O ' N TMS I H

2 7 0 269 (87%)

(a) n-BuLi, THF, -78°C; (b) NaH, TMEDA; (c) CBZCI; (d) LDA, THF, -78°C; (e) TMSCH 2I; (f) MeU, THF, -78°C.

Reaction of alcohol 265 with amine equivalent 269 under Mitsunobu conditions afforded compound 271 in 94% yield (Scheme LIX ).71 Hydrogenolysis of 271 in the presence of a catalytic amount of palladium hydroxide on carbon afforded the corresponding diamine- sulfonamide which was reacted without purification with thiocarbonyldiimidazole to afford thiourea 272 in a 51% overall yield .31 The thiocarbonyl moiety in 272 was activated by treatment with iodomethane ,32 and cyclization to guanidine 273 was accomplished by treatment with /V(/V-diisopropylethylamine, as described by Schmidtchen .34 Guanidine 273 was purified by column chromatography over activity grade II basic alumina and isolated in 81% yield. The last transformation required for the synthesis of a guanidine of type 177 was the cleavage of the ferf-butyl ester moiety, which was accomplished by treatment with gaseous hydrochloric acid .88 Guanidine 274 was isolated in 93% yield. 64

Scheme LIX. Synthesis of Guanidine 274

Ph. Ph- 'N COOf-Bu COOf-Bu

phs ^ N\ A 1 SES I ^ N , ,OH .N. .N. CBZ C BZ'' v v CBZ 2 6 5 271 (94%)

b ,c

COOf-Bu r^ - H - ^ Y ' COOH

N N‘ 'N " S ^ N i a - i I I .SO, H ,^^502 H H TMS' TMS' 274 (93%) 273 (81%) 272 (51%)

(a) 269, Ph 3P, DEAD, THF; (b) 60 psi H2, cat. Pd(OH) 2/C, EtOH; (c) (lm)2CS, CH2CI2; (d) Mel, MeOH; (e) EtN(APr)2, CH 2CI2; (f) HCI, CH2CI2.

F. Synthesis of Ptllomycalln A Analog 14

The next issue to be addressed in the synthesis of ptilomycalin A analog 14 was formation of the ester bond between guanidine 274 and alcohol 174. It appeared that this transformation could be accomplished using a carbodiimide-mediated coupling. Indeed, when guanidine 274 and alcohol 174 were reacted with dicyclohexylcarbodiimide in the presence of

4-dimethylaminopyridine, guanidine 275 was isolated in 65% yield .47 65

Scheme LX. Dlcyclohexylcarbodlimlde-Medlated Coupling of 274 and 174

0^ ,0 C H 2Ph

XOOH ^N.

^ O

'S° 2 N^^OCHjPh 14 o H * 2 7 4 1 7 4 DCC 4-DMAP DMF

CBZ

,SO;

CBZ O 275 (65%)

The next transformation was removal of the protecting groups. The 2- trimethylsilylethylsulfonyl protecting group is usually cleaved by treatment with tetrabutylammonium fluoride or cesium fluoride .88-90 However, when guanidine 275 was reacted under these conditions, ester hydrolysis occurred along with sulfonamide cleavage

(Scheme LXI). This unusual reactivity could be attributed to the basicity of the reagents or to the reaction conditions, as cleavage of the protecting group occurred at 80°C. 66 Scheme LXI. Attempted Cleavage of the Sulfonamide Moiety in 275

aorb Ester hydrolysis along with sulfone TMS cleavage

o 2 7 5

(a) n-Bu 4NF, DMF; (b) CsF, DMF.

Thus, the deprotection of the guanidine moiety in 274 had to be accomplished before esterification with alcohol 174. As shown in Scheme LXII, reaction of guanidine 274 with tetrabutylammonium fluoride at 80°C afforded a quantitative yield of guanidine 276.

Scheme LXII. Fluoride-Mediated Cleavage of Sulfonyl-Guanidine 274

,COOH •COOH

i c r i i a - i so2 H H H TMS 2 7 4 276 (100%)

(a) n-Bu 4NF, DMF; (b) HCI.

The interesting FAB mass spectrum of compound 276 is shown in Figure 9. In the gas phase, compound 276 loses HCI to give the corresponding guanidinium carboxylate, which then associates with itself. The resulting dimer, trimer, tetramer and pentamer all appear in the mass spectrum at m/e 184 ((M+-HCI)+1), 367 ((M+-HCI) 2+1), 550 ((M+-HCI)3+1), 734 ((M+-

HCI)4+1), 916 ((M+-HCI) 5+1). The polar interactions involved in the association process are depicted by the imaginative hexamer in Figure 10. 67

Figure 9. FAB Mass Spectrum of 276

N. .N

H H

0 ^ 0

r *i . N . . N .

'N N u

Figure 10. Guanldlnium Carboxylate Self-Association Scheme LXlll. Synthesis of Analog 14

Os. .OCH2Ph

CO”N + N I ci" ■ H H N OCH2

2 7 6

CBZ

CBZ O

277 (55%)

b,c

o 14 (70%)

(a) EDCI, cat. 4-DMAP, DMF; (b) Pd/C, 1,4-cyclohexadiene; (c) HCI, MeOH. 69 The best procedure for the coupling of guanidine 276 and alcohol 174 involved the

use of 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide hydrochloride (EDCI) in the presence of a catalytic amount of 4-dimethylaminopyridine (Scheme LXIII ) 91 The isolated yield of guanidine

277 was only 55%. This modest yield was partially due to the high affinity of 277 for silica gel.

Initially, we planned to synthesize compound 14 as the guanidine diamine. For this purpose, catalytic transfer hydrogenolysis was conducted on 277 to afford the desired compound in

70% yield. However, this material underwent rapid decomposition at room temperature. This fact could be rationalized by the high nucleophilicity of the guanidine and primary amine

moieties. Intermolecular amide formation is a potential decomposition pathway. The synthesis of analog 14 was therefore completed by catalytic transfer hydrogenolysis of both benzyl carbamates, followed by titration with a solution of hydrochloric acid in methanol .92 Analog 14 was prepared in 70% yield as the trihydrochloride salt by this procedure.

In summary, compound 14, a simple analog of ptilomycalin A has been synthesized via

ester bond formation between guanidine 276 and alcohol 174. Guanidine 276 was prepared

in ten steps from fert-butyl 2 -bromomethyl acrylate 252 in 16% overall yield. Compound 14 has

been submitted for biological activity evaluation. The next chapter will discuss our studies

toward the synthesis of compound 15, a more elaborate tricyclic structural analog of ptilomycalin

A. CHAPTER V

STUDIES TOWARD THE SYNTHESIS OF A TRICYCLIC

STRUCTURAL ANALOG OF PTILOMYCALIN A

A. Retrosynthetic Analysis.

Our next synthetic challenge was the synthesis of ptilomycalin A analog 15 shown in

Figure 8 and Scheme LXIV. The vessel subunit of compound 15 is a tricyclic structure having an internal bicyclic guanidine, which is attached via an ester bond to the amido-alcohol subunit of ptilomycalin A. The synthesis of compound 15 was to provide us with methodology for building the tricyclic internal core of ptilomycalin A with the right cis stereochemistry.

Retrosynthetically, ptilomycalin A analog 15 was to arise from esterification of tricyclic structure

278 with alcohol 174 (Scheme LXIV).

The retrosynthesis of compound 278 is shown in Scheme LXV. Guanidine 278 was to arise from the cyclization of triamine 279 onto an appropriate one-carbon synthon, according to the methodology used for the synthesis of ptilomycalin A analog 14. Triamine 279 was to be prepared by reduction of compound 280, which was to arise from a sulfide contraction between thiolactam 281 and an appropriate cyanoacetate derivative. Our plan was to devise an enantioselective synthesis. Therefore, thiolactam 281 (R‘ = H, protecting group; R" = CN,

COOEt or OR) was to be prepared from the commercially available and enantiomerically pure L- pyroglutamic acid (282).

70 71 Scheme LXIV. Retrosynthetic Analysis of Analog 15

1 5

O ^^O C H gPh

,COOH

O u HO N ^X )C H 2Ph I H 2 7 8 1 7 4

Scheme LXV. Retrosynthetic Analysis of Guanidine 278

,COOH ,COOR ,COOR

HOOC''* N O

2 8 2 28 1 72 B. Synthesis of a Thiolactam of Type 281.

The synthesis of a thiolactam of type 281 started with L-pyroglutamic acid (282) which was treated, according to Silverman's procedure, with thionyl chloride in ethanol to afford ethyl ester 283 in 84% yield (Scheme LXVI ).93 Silverman had also reported that reduction of ester

283 with lithium borohydride afforded the corresponding alcohol. However, repeating this experiment afforded a mixture of alcohol and boron salts which could not be purified.

Scheme LXVI. Preparation and Attempted Reduction of Ester 283

Hv/~V mixture EtO-jC^N C of product and z I boron salts H 2 8 2 283 (84%)

(a) SOCI2, EtOH; (b) UBH4, THF.

Scheme LXVII. Preparation and Attempted Transformations of Ester 284

b, c, d decomposition EtOoC N EtOjC N z I ) H *OMe

2 8 3 284 (85%)

e phosphorus E t O ^ N ^ 0 insertion

L OMe 2 8 4

(a) MOMCI, EtN(r-Pr)2, CH2CI2; (b) CHBr 2U, THF; (c) n-BuLi; (d) AcCI, EtOH; (e) Lawesson's reagent, CH 2CI2. 73 The amide moiety in 283 was therefore protected with a methoxymethyl group to afford

ester 284 in 85% yield (Scheme LXVII ).68 The synthesis of a thiolactam of type 281 required a

one-carbon homologation of the ester moiety. In 1985, Kowalski and coworkers reported that

treatment of esters with dibromomethyllithium followed by n-butyllithium afforded the one-

carbon homologated ester in good yield .94 Attempted one-carbon homologation of the ester

moiety in 284, however, afforded a complex mixture of products. Moreover, an attempt to

convert the lactam into a thiolactam by treatment with Lawesson's reagent afforded a mixture of

products .58 1H NMR analysis of the crude reaction mixture showed that decomposition of the

methoxymethyl group and phosphorus insertion had occurred.

Scheme LXVIII. Synthesis of Thiolactam 287

EtOoC N u ► EtO,C N 5 9 ------► Et02C N ► " 1 1 L L H H 'OM e OMe 2 83 285 (98%) 286 (79%) 287(74% )

(a) Lawesson’s reagent, Cf-feCfe; (b) MOMCI, EtN(APr) 2, CH2CI2; (c) NaBH4, MeOH.

Thus, the conversion of the lactam into a thiolactam had to be carried out prior to

introduction of the protecting group. As shown in Scheme LXVIII, treatment of ester 283 with

Lawesson's reagent in dichloromethane afforded thiolactam 285 in 98% yield .58 Reaction of thiolactam 285 with methoxymethyl chloride and Hunig's base in dichloromethane afforded thiolactam 286 in 79% yield .68 Subsequent reduction of the ester moiety in 286 with sodium

borohydride in methanol yielded alcohol 287 in 74% yield .61

Alcohol 287 was a suitable substrate for one-carbon homologation, as it could potentially be converted into a nitrile. Our attempts to carry out this transformation are summarized in Scheme LXIX. The mesylate and tosylate derivatives 288 and 289 were prepared from alcohol 287 in 76% and 88 % yield, respectively .95 Treatment of 288 or 289 74 with sodium cyanide in dimethylsulfoxide did not effect the desired transformation, and starting material was recovered .96 Reaction of alcohol 287 with potassium cyanide, 18-crown-6, tributylphosphine and carbon tetrachloride in acetonitrile, according to the procedure of Shioiri and coworkers also failed .97 It was therefore decided to investigate the feasibility of the sulfide contraction and carry out the one-carbon homologation at a later stage of the synthesis.

Scheme LXIX. Attempted Nltrile Synthesis from Alcohol 287

No reaction

k OMe J ^"OMe 2 8 7 288 (76%)

HO TsO, No reaction k I OMe k*OMe , 2 8 7 289 ( 8 8 %) HO No reaction ) k OMe 2 8 7

(a) MsCI, Et3N, DMAP, CH2CI2; (b) NaCN, DMSO;(c) TsCI, Et 3N, DMAP, CH2CI2; (d) KCN, 18-crown-6, n-BuaP, CCI 4, CH3CN.

C. Sulfide Contraction.

The sulfide-contraction reaction was first introduced in 1971 by Eschenmoser and coworkers .98 This transformation, depicted in Scheme LXX, provides a route for the synthesis of vinylogous amides and urethanes. Reaction of thiolactam 290 and a-bromo carbonyl compound 291 affords compound 292, which upon treatment with base and triphenylphosphine, affords vinylogous amide or urethane 293. 75 Scheme LXX. Eschenmoser's Sulfide Contraction

H I

2 9 0 X base, PPh3 h°Y X +

Br R2

2 9 2 2 9 3 O 291 X=OR', alkyl

This reaction has been widely applied to natural product synthesis," and the intramolecular version has been investigated by Ireland and coworkers, and applied to the synthesis of diplodialide A .100 A similar transformation was introduced in 1981, which provided methodology for converting N-alkyl lactams to vinylogous amides and urethanes via

(methylthio)alkylideniminium salts .101 As shown in Scheme LXXI, treatment of a thiolactam of type 294 with methyl iodide afforded a (methylthio)alkylideniminium salt of type 295, which upon treatment with base and an active methylene compound yielded vinylogous amides or urethanes of type 296 in yields ranging from 53% to 85%.

Scheme LXXI. Synthesis of Vinylogous Amides and Urethanes via

(Methylthio)aikylideniminium Salts

YCHaCOX base N SMe O I I R R R Y

2 9 4 2 9 5 2 9 6

X = OR\ alkyl Y = COOR, H. CN 76 This methodology seemed to best suit our needs for the synthesis of a compound of type 280. The synthesis of (methylthio)alkylideniminium salt 298 is shown in Scheme LXXII.

Protection of the hydroxyl group in 287 was accomplished by reaction with tert- butyldimethylsilyl chloride and imidazole to afford thiolactam 297 in 99% yield .62 Treatment of compound 297 with methyl iodide in diethyl ether afforded salt 298 in 74% yield .102

Scheme LXXII. Synthesis of Salt 298

a ^ TBDMSO~Hp C ~ \ s s s b „ TBDMSO^ SMe

^"-OMe ^'•OMe ^"*OMe 2 8 7 297 (99%) 298 (74%)

(a) TBDMSCI, imidazole, DMF; (b) Mel, Et 2 0 .

Scheme LXXIII. Preparation of |3-Ketoesters 300 and 302

o o a, b, c MeOAX 2 9 9 300 (54%)

o o a, b, c

f-BuO*XX

301 302 (69%)

(a) NaH, THF; (b) n-BuLi; (c) 4-bromo-1-butene

It was decided at this stage to react compound 298 with various active-methylene compounds to investigate the scope of the reaction. As shown in Scheme LXXIII, [J-ketoesters

300 and 302 were prepared by alkylation of the dianions of alkyl acetoacetates 299 and 301 in 54% and 69% yield respectively .103 77 Scheme LXXIV. Synthesis of Vinylogous Urethanes 303, 304 and 305

TBDMSO. TBDMSO.

OMe MeO

2 9 8 303 (29%)

TBDMSO. SMe TBDMSO

OMe MeO" O

2 9 8 304 (37%)

hJ v H COOEt TBDMSO TBDM SO ^^ ^ o ^ N ^ - S M e N J CN OMe MeO'

2 9 8 305 (73%)

(a) 302, K2C 03i DMF; (b) 301, K 2C03, DMF; (c) ethyl cyanoacetate, K 2C03, DMF.

As shown in Scheme LXXIV, reaction of salt 298 with p-keto-ester 302 and potassium carbonate in /V,A/-dimethylformamide afforded only 29% of vinylogous urethane

303. This low yield could be attributed to the steric bulk of p-ketoester 302, which may prevent coupling. Vinylogous urethane 303 may also be quite unstable under the basic reaction conditions. When salt 298 was reacted with p-ketoester 301, compound 304 was isolated in

37% yield. However, we were pleased to see that reaction of salt 298 with ethyl cyanoacetate afforded vinylogous urethane 305 in 73% yield. The stereochemistry of the double bond in compound 305 is shown as being (E). However, a signal at 5 69.6 ppm in the 13C NMR spectrum for the carbon a to the cyano and ester moieties suggests that compound 305 is a zwitterion. Charge stabilization at this carbon is provided by the two electron-withdrawing 78 stabilization at this carbon is provided by the two electron-withdrawing groups. Compound 305 was a suitable substrate for one-carbon homologation.

D. One-Carbon Homologation.

The one-carbon homologation of compound 305 was accomplished as shown in

Scheme LXXV. Compound 305 was reacted with tetrabutylammonium fluoride to afford alcohol

306 in 89% yield .62 Reaction of 306 with methanesulfonyl chloride and triethylamine in the presence of a catalytic amount of 4-dimethylaminopyridine afforded mesylate 307 in 87% yield .95 Subsequent displacement of the mesylate in 307 with cyanide in dimethylsulfoxide afforded nitrile 308 in 63% yield .96 Finally, the methoxymethyl protecting group was cleaved using hydrochloric acid in tetrahydrofuran to afford nitrile 309 in 96% yield.

Scheme LXXV. One-Carbon Homologation of 305

30 5 306 (89%) 307 (87%)

309 (96%) 308 (63%)

(a) 0 -BU4NF, THF; (b) MsCI, Et 3N, DMAP, CH2CI2; (c) NaCN, DMSO; (d) HCI, THF. 79 The next synthetic transformation required for the synthesis of a compound of type

279 was double-bond reduction.

E. Attempted Double-Bond Reduction.

Our attempts to reduce the double bond in compound 305 are summarized in Scheme

LXXVI. It was hoped that compound 305 could be reduced by treatment with sodium

cyanoborohydride in methanol at pH 4, according to the procedure described by Borch and

coworkers .104 However, no reaction occurred under these conditions. Catalytic hydrogenation

of 305 with palladium on carbon as the catalyst also failed .105 Hydride transfer reagents such

as sodium borohydride and lithium aluminum hydride did not accomplish the desired transformation. Attempted reduction with lithium in ammonia was also unsuccessful .106

Scheme LXXVI. Attempted Reduction of 305

NaBH3CN hJ V COOEt i HCI, MeOH

CN 50psiH2 MeO' PcVC, MeOH 3 0 5 LiAIH4 No reaction I or NaBH 4

Li/NH3l THF f-BuOH

At the same time, reduction of nitrile 308 was attempted. As shown in Scheme LXXVI I, attempted reduction with sodium cyanoborohydride in acidic methanol was unsuccessful .104

When compound 308 was treated with lithium in ammonia in the presence of fe/T-butanol as the proton source, compound 310 was isolated in low yield .106 Compound 310 results from hydrogen-abstraction from the methylene group next to the nitrile moiety, followed by p- elimination and reduction of the resulting double-bond. 80 Scheme LXXVII. Attempted Reduction of 308

NaBHaCN H v / V COOEt HCI, MeOH No reaction CN MeO' 3 0 8 .COOEt NC HN + 308 (47%) CN MeO

310 (8 %)

In addition, attempted reduction of compounds 305 and 308 with sodium cyanoborohydride in trifluoroacetic acid afforded, along with unreacted starting material, a compound where the methoxymethyl group had been reduced to a methyl .107 This problem was avoided by directing our efforts toward the reduction of nitrile 309. Our attempts to reduce compound 309 are summarized in Scheme LXXVI 11. When nitrile 309 was reacted with sodium cyanoborohydride in trifluoroacetic acid, no reaction occurred .107 Starting material was also

Scheme LXXVIII. Attempted Reduction of Nitrile 309

NaBH3CN H * V COOEt TFA NC.

\ CN NaBH 4 AcOH 3 0 9

L1AIH4 THF

EtaSiH No reaction TFA, CHCI3 1

50 psi H2, AcOH Pt/A IA

50 psi H2, AcOH Rh/AIA 81 recovered when 309 was reacted with sodium borohydride in acetic acid .108 Lithium aluminum hydride reduction of 309 was also unsuccessful. The triethylsilane-trifluoroacetic acid reagent combination is a powerful reducing agent .109 Attempted reduction of 309 under these conditions, however, met with failure. Compound 309 was also submitted to stronger catalytic hydrogenation conditions, but double-bond reduction did not occur.

A possible explanation for the lack of reactivity of nitrile 309 when submitted to ionic reduction reaction conditions may be explained by the mechanism of the reaction, shown in

Scheme LXXIX. Ionic reduction of compound 309 requires protonation to afford iminium ion

311. Subsequent hydride transfer affords the reduction product 312. However, the pKa of iminium ion 311 is probably smaller than 1, as the carbon bearing Hi is attached to three strong electron-withdrawing groups. Protonation of 309 therefore requires a very strong acid, incompatible with a reducing agent.

Scheme LXXIX. Mechanism for the Ionic Reduction of 309

,COOEt

3 0 9 311 3 1 2

Further inspection of the literature revealed that the reduction of a compound similar to

309 had been reported by Bachi and coworkers .110 As shown in Scheme LXXX, the double bond in compound 313 was reduced by catalytic hydrogenation in a mixture of trifluoroacetic acid and acetic acid at 60 psi in the presence of platinum oxide. The reaction products were compound 314 as a mixture of two epimers and compound 315. Compound 314 , the desired product, was a cis substituted pyrrolidine derivative.

Compound 309 was therefore submitted to the same hydrogenation conditions. Thin- layer chromatography of the resulting products mixture revealed disappearance of the starting material, and appearance of very polar inseparable compounds. However, 1H NMR analysis of 82 the crude reaction mixture did not allow for the identification of the reaction products, even after

peracetylation of the reaction mixture. We felt at this point that a new approach to guanidine

278 needed to be devised.

Scheme LXXX. Bachi's Reduction of Vinylogous Urethane 313

O 60 psi H2, PtOj OH

/, COzEt ,!, C02Et h COOEt

3 1 3 314 (39%) 315(50% )

In summary, an approach to the synthesis of tricyclic guanidine 278 was described.

This route led to the synthesis of compound 309 which could not be converted to a compound of type 279. Although other routes to compound 278 can be envisioned, we decided at this

point to direct our efforts toward the synthesis of ptilomycalin A analog 16. Our studies in this

area are described in the next chapter. CHAPTER VI

STUDIES TOWARD THE SYNTHESIS OF A PENTACYCLIC

STRUCTURAL ANALOG OF PTILOMYCALIN A

A. Retrosynthetic Analysis.

Our last objective was to synthesize ptilomycalin A analog 16, shown in Figure 8 and

Scheme LXXXI. The vessel subunit of compound 16 is a pentacyclic structure having two spiro aminals, as well as an internal bicyclic guanidine, and the pentacycle is attached to the amido- alcohol portion of ptilomycalin A via an ester linkage. As shown in Scheme LXXXI, compound

16 was to arise from ester bond formation between pentacyclic structure 316 and amido- alcohol 174.

The retrosynthetic analysis of compound 316 is shown in Scheme LXXXII. Our plan was to first address the cis stereochemistry issue and the amidal synthesis problem, and a compound of type 317 was an appropriate target in this regard. Compound 317 was to be further elaborated by synthetic transformations of the pyrrolidine side-chain. Tricyclic structure

317 was to arise from ozonolysis, reduction and cyclization of bicycle 318. Compound 318 was to be prepared from ketone 320, which would in turn arise from reduction of vinylogous amide 319. Again, our plan was to devise an enantioselective synthesis of 16. Thus, compound 319 was to be prepared from sulfide contraction of a suitable bromoketone and an appropriate thiolactam derived from L-pyroglutamic acid (282).

83 84 Scheme LXXXI. Retrosynthetic Analysis of Analog 16

N NH

TJ 1 6

O^^OCHaPh

,COOH

NA. OCHoPh H0-tT Y I 14 o H 3 1 6 174

B. Synthesis of a Vinylogous Amide of Type 320.

Our plan was to prepare a vinylogous amide of type 320 using the sulfide contraction reaction discussed above .98 Thiolactam 297 (Scheme LXXII) derived from L-pyroglutamic acid, was an appropriate substrate for this reaction. To test the feasibility of our approach, the readily available bromoacetone was selected as the bromoketone .110 As shown in Scheme LXXXIII, reaction of thiolactam 297 with bromoacetone afforded vinylogous amide 321 in 69% yield. 85 Scheme LXXXII. Retrosynthetic Analysis of Pentacyclic Structure 316

,COOH RO, "O" :>

3 1 6 3 1 7

31 9

•ST\ HOOC' 1 N ^ O I H 3 2 0 2 8 2

Scheme LXXXIII. Preparation of Vinylogous Amide 321

TBDMSO^ s a, b TBDMSO^

^OMe MeO^

2 9 7 321 (69%)

(a) bromoacetone, CH 2CI2; (b) PPh 3, Et3N, CH2CI2.

A compound of type 320 could possibly be prepared by kinetic alkylation of the vinylogous amide moiety of compound 321 with 4-bromo-1-butene. A preliminary study involved the reaction of vinylogous amide 321 with lithium diisopropylamide, followed by 86 treatment with benzyl bromide (Scheme LXXXIV). Under these kinetic conditions, however, compound 322 resulting from y-alkylation was isolated in 34% yield. Compound 322 was a

2.5:1 mixture of diastereomers. Replacing diisopropylamine with 2,2,6,6-tetramethylpiperidine did not promote a-alkylation. In addition, the reduction of vinylogous amide 321 was investigated. When compound 321 was treated with sodium cyanoborohydride and hydrochloric acid in methanol, reduction of the methoxymethyl group as well as reduction of the double bond occurred, and compound 323 was isolated in 42% yield .104 1H NMR analysis showed compound 323 to be a single diastereomer, but its stereochemistry was not determined. Nevertheless, the isolation of compound 323 indicated that reduction of the double bond had to be conducted on a substrate where the methoxymethyl group had been hydrolyzed.

Scheme LXXXIV. Alkylation and Reduction of Vinylogous Amide 321

CH2Ph

TBDMSO^‘S *C ^ 5 s^ X ^ s‘ Me 3| b 9 TBD M SO ^

MeO^ MeO^ 321 322 (34%)

O O ^ ^ ^ M e C ^ TBDMSO^>(^X^Af

J Me MeO 321 323 (42%)

(a) LDA, THF, -78°C; (b) PhCH 2Br; (c) NaBH3CN, HCI, MeOH.

A compound of type 320 could alternatively be prepared via sulfide contraction between thiolactam 297 and 1-bromo-6-hepten-2-one (328). Thus, we turned our attention to the synthesis of 1 -bromo-6-hepten-2-one. In 1968, Regitz and coworkers reported that fomylation of methyl ketones followed by treatment with tosyl azide afforded the corresponding 87 diazoketones .111 The corresponding bromoketones can eventually be obtained from diazoketones by treatment with hydrobromic acid. This methodology was therefore applied to the synthesis of bromoketone 328 as shown in Scheme LXXXV. Treatment of ethyl acetoacetate (324) with sodium ethoxide followed by reaction with 4-bromo-1-butene afforded

P-ketoester 325 in 67% yield .112 Saponification of ester 325 with potassium hydroxide followed by decarboxylation of the resulting p-ketoacid afforded methyl ketone 326 in 77% yield .112 Subsequent formylation of ketone 326 followed by reaction with tosyl azide afforded a 25% yield of diazoketone 327.111 Treatment of 327 with hydrobromic acid yielded bromoketone 328 in 67% yield .113

Scheme LXXXV. Low-Yielding Synthesis of a-Bromoketone 328

328 (67%) 327 (25%)

(a) NaOEt, EtOH; (b) 4-bromo-1-butene; (c) KOH, EtOH. H 20 ; (d) 10% H2S 04; (e) NaH, EtOH, HCOOEt, Et 20 ; (f) TsN3, EtOH; (e), 48% HBr, Et 20.

Because of the low yield in the preparation of diazoketone 327, a-bromoketone 328 was eventually prepared via another sequence The synthesis of 5-hexenoyl chloride 333 from the expensive 5-bromo-1-pentene, and its subsequent conversion to bromoketone 328 had been reported by Oppolzer and coworkers .113 Our alternate synthesis of bromoketone 328 is 88 shown in Scheme LXXXVI. Reaction of ethyl 3-chloropropanoate (329) with sodium iodide in acetone afforded ethyl 3-iodopropanoate (330) in 97% yield. Preparation of the organozinc compound of 330, followed by coupling with aliyl tosylate in the presence of a catalytic amount of copper cyanide afforded ethyl hexenoate (331) in 77% yield .114 Saponification of ester

331 afforded carboxylic acid 332 in 77% yield. Treatment of 332 with thionyl chloride afforded hexenoyl chloride (333) in 70% yield .113 Reaction of acid chloride 333 with an excess of diazomethane, followed by treatment with hydrobromic acid afforded bromoketone 328 in 88 % yield .113

Scheme LXXXVI. Efficient Synthesis of a-Bromoketone 328

328 ( 8 8 %) 333 (70%) 332 (77%)

(a) Nal, acetone; (b) Zn-Cu, DMA, THF; (c) H 2C=CHCH2OTs, cat. CuCN, THF; (d) KOH, H20, EtOH; (e) SOCI2; (f) CH 2N2, Et20; (g) 48% HBr.

Sulfide contraction between thiolactam 297 and a-bromoketone 328 according to Eschenmoser's reaction conditions afforded vinylogous amide 334 in 68 % yield .98 Acidic hydrolysis of the methoxymethyl group could not be carried out on compound

334 as the ferf-butyldimethylsilyl protecting group was not stable under these conditions.

Vinylogous amide 334 was therefore treated with tetrabutylammonium fluoride to afford alcohol

335 in 74% Scheme LXXXVII. Synthesis and Deprotection of Vinylogous Amide 334

hJ-V a, b TBDMSO TBDMSO N

L MeO 2 9 7 334 (68%)

(a) 328, CH 2CI2 (b) PPh3, Et 3N, CH2CI2 (c) /j-Bu4NF, THF

MeO 335 (74%)

Scheme LXXXVIII. Benzylation of Alcohol 287

V HO. a, b decomposition J OMe 2 8 7 decomposition J

h< /~ ~ V BnO. S

^*OMe 336 (68 %)

(a) NaH, DMF; (b) PhCH 2Br; (c) PhCH 2CI, KOH, DMSO; (d) PhCH 2CI, cat. n-Bu4NHS04, 50% NaOH, C 6H6. 90 yield .62 Compound 335, however, was found to be unstable as decomposition to a bright red oil occurred upon standing at room temperature. Thus, the preparation of a benzyl protected thiolactam was undertaken, as benzyl groups are stable to acidic hydrolysis.

Attempted protection of alcohol 287 using sodium hydride followed by benzyl bromide afforded decomposition products .115 Decomposition was also observed when alcohol 287 was reacted with powdered potassium hydroxide and benzyl chloride in dimethylsulfoxide .116

Benzylation of alcohol 287 under phase-transfer catalysis, however, using benzyl chloride and a catalytic amount of tetrabutylammonium hydrogensulfate in 50% aqueous sodium hydroxide and benzene, afforded thiolactam 336 in 68 % yield .117 This rather low yield was attributed to thiolactam hydrolysis under the reaction conditions (Scheme LXXXVIII).

As shown in Scheme LXXXIX, sulfide contraction between thiolactam 336 and bromoketone 328 afforded vinylogous amide 337 in 69% yield.

Scheme LXXXIX. Synthesis of Vinylogous Amide 337

3 3 6 337 (69%)

(a) 328, CH 2CI2; (b) PPh3, Et 3N, CH2CI2.

The next transformation, prior to double bond reduction, was the cleavage of the methoxymethyl protecting group. Our attempts to accomplish this transformation are shown in

Scheme XC. Treatment of vinylogous amide 337 with various acidic media as well as attempted methoxymethyl group hydrolysis with trichloromethylsilane and sodium iodide in acetonitrile all afforded complex crude reaction mixtures .118- 119 1H NMR analysis seemed to indicate that geometrical isomerism had taken place under these reaction conditions. Indeed, protonation of vinylogous amide 337 or of the corresponding deprotected compound affords the 91 corresponding iminium ion, in which rotation around the former double bond takes place, affording geometrical isomers after deprotonation. Thin-layer chromatography analysis showed several products which could not be isolated.

Scheme XC. Attempted Oeprotection of Vinylogous Amide 337

acxfc Dowex-50 MeOH

cat. HO MeO THF 3 3 7 PPTS MeOH complex crude reaction mixture CljSiMe, Nat CH3 CN

AcOH HP

Scheme XCI. Attempted Deprotection of Thiolactam 336

cat HCI V THF BnO, no reaction J CtjSiMe, Nal OMe CH^CN 3 3 6 Me3SiBr CHjClg decomposition I

TFA

Thus, the deprotection of the methoxymethyl protecting group had to be accomplished prior to sulfide contraction. As shown in Scheme XCI, treatment of thiolactam 336 with a catalytic amount of hydrochloric acid in tetrahydrofuran afforded recovered starting material. 92 Reaction of thiolactam 336 with trichloromethylsilane and methyl iodide in acetonitrile afforded decomposition products .119 Decomposition was also observed when 337 was treated with bromotrimethylsilane in dichloromethane or with trifluoroacetic acid .120- 121

Thus, the methoxymethyl protecting group had to be hydrolyzed before thiolactam formation. As shown in Scheme XCII, lactam 284 was reduced to alcohol 338 with sodium borohydride in methanol .61 Subsequent benzylation of lactam 338 under phase-transfer conditions afforded lactam 339 in 89% yield .117 Treatment of lactam 339 with trifluoroacetic acid and water presumably afforded a compound where the methyl group had been replaced with a trifluoroacetate group. Treatment of this compound with lithium hydroxide afforded the corresponding hydroxymethyl derivative. However, addition of ethanolamine to the reaction mixture triggered the elimination of formaldehyde and lactam 340 was isolated in a 76% overall yield. A similar transformation for the deprotection of 2-trimethylsilylethoxymethyl-protected pyrroles and indoles (SEM protecting group) has been reported by Muchowski and coworkers .122

Scheme XCII. Synthesis of Lactam 340

EtOC^^N^^0 — ——► 2 LILA OMe OMe OMe 2 8 4 338 (85%) 339 (89%) 340 (76%)

(a) NaBH4, MeOH; (b) PhCH 2CI, cat. n-Bu4NHS04, 50% NaOH, C 6H6; (c) TFA, H20; (d) ethanolamine, 5M LiOH, MeOH.

The synthesis of vinylogous amide 342 is shown in Scheme XCIII. Reaction of lactam

340 with Lawesson's reagent in dichloromethane afforded thiolactam 341 in 86 % yield .58

Treatment of thiolactam 341 with bromoketone 328, followed by potassium bicarbonate work up and subsequent heating with potassium te/f-butoxide and tert-butanol in benzene afforded vinylogous amide 342 in 69% yield .98 The expected (Z) configuration around the double bond 93 was confirmed by a signal for the hydrogen-bonded amide proton at 5 9.9 ppm in the 1H NMR spectrum of 342. The next synthetic transformation was double bond reduction.

Scheme XCIII. Synthesis of Vinylogous Amide 342

BnO I I H H

3 4 0 341 (86%) 342 (69%)

(a) Lawesson's reagent, CH 2CI2; (b) 328, CHCI3; (c) satd. aq. KHC03; (d) PPh3l cat. f-BuOK, f-BuOH, C 6H6.

C. Double Bond Reduction and Stereochemistry Determination.

As shown in Scheme XCIV, treatment of vinylogous amide 342 with sodium cyanoborohydride in acidic methanol afforded a 2.5:1 mixture of diastereomeric amino-alcohols

343 and 344 in 82% yield. Initially, it was expected that this reaction would afford the corresponding p-aminoketone. Reduction of the carbonyl group, however, occurs concommitently with double bond reduction, and it was not possible to stop at the ketone stage. In addition, in an attempt to prepare a compound of type 319, alcohols 343 and 344 were submitted to Jones oxidation and Swern oxidation reaction conditions.72’ 123 In both cases, an inseparable mixture of diastereomeric ketones were obtained.

The stereochemical outcome of the sodium cyanoborohydride-mediated reduction of vinylogous amide 342 was not easily elucidated, as compounds 343 and 344 were both oils.

The relative stereochemistry at C 2 and C 4 in compounds 343 and 344 was established by two sets of experiments. 94 Scheme XCIV Reduction of Vinylogous Amide 342

BnO

3 4 2

NaBH3CN HCI, MeOH

3 4 3 3 4 4 2.5:1 (82%)

We first had to determine whether or not compounds 343 and 344 were epimeric at

C2. Thus, the first objective was to replace the hydroxyl group with a hydrogen so that the only unknown stereocenter left was at C 2. This was accomplished via the reaction sequence shown in Scheme XCV. Reaction of amino-alcohols 343 and 344 with methyl chloroformate and potassium carbonate in acetone afforded methyl carbamates 345 and 346 in 69% yield .124

Subsequent double bond catalytic hydrogenation afforded carbamates 347 and 348 in 94 % yield. Xanthates 349 and 350 were prepared in 84% yield by treating 347 and 348 with sodium hydride and carbon disulfide along with a catalytic amount of imidazole, followed by methyl iodide .125 The mixture of xanthates 349 and 350 were reduced with tributyltin hydride .126 Two diastereomers were obtained, indicating that the starting amino-alcohols 343 and 344 were epimeric at C 2 - Separation of the two diastereomers was accomplished by column chromatography over silica gel to afford 21% of carbamate 351 and 52% of carbamate

3 5 2 . 95 Scheme XCV. Hydroxyl Group Reduction In Amino-Alcohols 343 and 344

343 + 344 (C2 epimer) 345 + 346 (C 2 epimer) (69%)

BnO N

O'" 'O M e O ' OMe

349 + 350 (C 2 epimer) (84%) 347 + 348 (C 2 epimer) (94%)

351 (21%) 352 (52%)

(a) MeOCOCI, K 2C03l acetone; (b) Pd/C, 30 psi H2i EtOH; (c) NaH, CS2l cat. imidazole, THF; (d) Mel; (e) n-Bu 3SnH, PhCH3.

The relative stereochemistry between C 2 and C 4 was established by NOE studies on cyclic carbamates 353 and 354 (Scheme XCVI). Repeated chromatography of the amino- alcohol mixture gave a small amount of pure amino-alcohol 343. Compound 343 was reacted with carbonyldiimidazole in benzene to afford cyclic carbamate 353 in 76% yield .56 This 96 experiment was repeated on a 1:1 mixture of amino-alcohols 343 and 344 to afford cyclic carbamate 353 in 34% yield and cyclic carbamate 354 in 36% yield.

Scheme XCVI. Synthesis of Carbamates 353 and 354

(lm)2CO Q3H6 H W h BnO. BnO

3 4 3 353 (76%)

BnO

(lm)2CO 353 (34%) CeHs

BnO, 343 +344 (1:1 mixture at C2)

354 (36%)

The results of the NOE experiments conducted on cyclic carbamates 353 and 354 are summarized in Figure 11. In compound 353, irradiation of the hydrogen at C 2 produced a 7% enhancement for the hydrogen at C 4. No enhancement was observed between the hydrogens at C2 and C 5 . In compound 354, no enhancement was observed between the hydrogens at

C2 , C4 and C 5. These experiments allowed us to determine the relative stereochemistry at C 2 and C 4. However, no irrefutable proof for the relative stereochemistry between C 2 and C 5 was obtained. 97

r r . H4 / ^ H ' “\ - N 0% BnO. BnO,

oA ' o i r OI ' joa r ^ PH S * '

353 3 5 4

Figure 11. NOE Experiments on Cyclic Carbamates 353 and 354

The absolute stereochemistry shown for amino-alcohols 343 and 344 is supported by a related literature precedent reported by Rapoport and coworkers .990 As shown in Scheme

XCVII, reduction of vinylogous carbamate 355 with sodium cyanoborohydride in acidic methanol afforded a 3:1 mixture of diastereomers 356 and 357. It was determined that the major product had the cis stereochemistry.

Scheme XCVII. Rapoport’s Reduction of Vinylogous Carbamate 355

___ NaBH3CN , , .

^ X X - co=e' i ■ i Bn Bn Bn

355 356 357

It is therefore reasonable to assume that the benzyloxymethyl side chain in vinylogous amide 342 provides sufficient steric hindrance for the reduction to predominantly occur from the f3-face. Thus, the major amino-alcohol diastereomer 343 obtained from this reaction is shown with cis stereochemistry at C 2 and C 5 . However, since no X-ray structure of a solid derivative was obtained, the stereochemistry at C 2 and C 4 in 343 and 344 might be reversed. 98 D. Studies Toward the Synthesis of a Compound of Type 318.

Although we were not able to synthesize a compound of type 319, further elaboration of alcohols 345 and 346 was possible and could potentially lead to a compound of type 318

Scheme XCVIII. Synthesis of Cyclic Ureas 364 and 365

SES BOC N Of-Bu h J > h 7 BnOw

O ' OMe O ^^O M e 345 + 346 (C2 epimer) 358 + 359 (C2 and C4 epimer) (75%)

Of-Bu BnO, Hs O : H; BnO, b O J

O ' 'O M e

362 + 363 (C2 and C 4 epimer) (82%) 360 + 361 (C2 and C 4 epimer) (92%)

+ mixture (17%)

(a) PPh3, DEAD, THF; (b) n-Bu 4NF, THF; (c) TMSCI, Nal, CH3CN; (d) Me 3AI, PhCH3. 99 via cyclic urea synthesis followed by oxidation.

The synthesis of diastereomeric cyclic ureas 364 and 365 is shown in Scheme XCVIII.

A 2.5:1 mixture of carbamates 345 and 346 was reacted with amine equivalent 217 under

Mitsunobu conditions to afford diastereomeric carbamates 358 and 359 in 75% yield .70

Cleavage of the sulfonamide moiety was accomplished by treating 358 and 359 with tetrabutylammonium fluoride to afford carbamates 360 and 361 in 92% yield .88 Treatment of

360 and 361 with chlorotrimethylsilane and sodium iodide in acetonitrile afforded amines 362 and 363 in 82% yield .127 Cyclization to cyclic ureas 364 and 365 was accomplished in 63% yield by treating amines 362 and 363 with trimethylaluminum in toluene .128 Ureas 364 and

365 were partially separated by chromatography. Thus, NOE experiments were performed on both compounds. To our dismay, no enhancement between hydrogens at C 2 , C4 and C 5 was observed in any diastereomer. The absolute stereochemistry shown in Scheme LILVIII was therefore attributed to cyclic ureas 364 and 365. The absolute stereochemistry for compounds 358 to 363 was deduced from the stereochemical assignment for 364 and 365.

Thus, it appeared that major diastereomer 345 underwent inversion of configuration at C 4 when reacted under Mitsunobu conditions. Mitsunobu reaction of minor diastereomer 346, however, proceeded with retention of configuration, via neighboring group participation of the carbamate .129

We would like to point out that the stereochemical assignment for minor amino-alcohol as 344 is bothersome in two ways. First, the relative stereochemistry at C 2 and C 4 in amino- alcohols 343 and 344 might be expected to be the same, because hydride delivery at C 4 to a possible chelated intermediate amino-ketone should occur cis to the hydrogen at C 2- If the stereochemical assignment of 344 is correct, however, the relative stereochemistry at C 2 and

C4 is different. The second bothersome fact is that to explain the stereochemical course of the

Mitsunobu reaction, the major isomer has to undergo inversion of configuration at C 4 while the minor isomer must undergo double inversion. This also bothered us. Thus, another possible stereochemical outcome for the reduction of vinylogous amide 342 is proposed in Scheme

XCIX. Suppose that reduction of vinylogous amide 342 affords a 2.5:1 mixture of amino- 100 alcohols 343 and 366, which have the same relative stereochemistry at C 2 and C 4. Reaction of

366 with carbonyldiimidazole would afford cyclic carbamate 367 shown as the C 4 epimer of compound 354. The fact that no NOE is observed for 367 is bothersome, but a possible explanation is that the trans stereochemistry across the pyrrolidine ring may favor a conformation in which hydrogens at C 2 and C 4 are too far away observe an NOE. When compound 366 is subjected to the Mitsunobu-cyclization sequence discussed above, cyclic urea 365 would be obtained after inversion of configuration at C 4 . The fact that no NOE was observed in compound 365 fits the proposed absolute stereochemistry. In summary, if the relative assignment at C 2 and C 5 is correct, the minor isomer obtained from the reduction of 342 could be either 344 or 366. The latter seems more reasonable, but no irrefutable proof of stereochemistry has been obtained.

Scheme XCIX. Alternative Stereochemical Outcome for the Reduction of 342

353 3 6 7

NaBH3CN HCI, MeOH 101 In summary, an approach to the synthesis of ptilomycalin A analog 16 was investigated.

This route was based on sulfide contraction methodology followed by double bond reduction of the resulting vinylogous amide, and led to a mixture of two diastereomers. Further synthetic transformations allowed for the synthesis of cyclic ureas 364 and 365, possible precursors to a structure of type 318. However, this approach presents little synthetic utility as no definitive proof of the stereochemical outcome of the vinylogous amide reduction was established. Thus, a new route to ptilomycalin A analog 16 needs to be designed.

The next chapter will present two recently published approaches to Ptilomycalin A along with our general conclusions about our studies. CHAPTER VII

RECENTLY PUBLISHED APPROACHES TO THE

TOTAL SYNTHESIS OF PTILOMYCALIN A AND

GENERAL CONCLUSION

A. Introduction.

In 1993, two approaches to the total synthesis of ptilomycalin A appeared in the

literature. The first approach was reported by Snider and coworkers, who accomplished a biomimetic synthesis of the internal tricyclic core of ptilomycalin A using a concept similar to the one used in their synthesis of crambines A and B .130- 131 The second approach was published by Overman and coworkers, who prepared an advanced tricyclic intermediate, via a tethered

Biginelli condensation, which can be further elaborated to the natural product .132 In this chapter, these two approaches will be presented and conclusions concerning our studies will be drawn.

B. A Biomimetic Synthesis of the Internal Tricyclic Core of Ptilomycalin A.

In 1992, Snider and coworkers reported the synthesis of crambines A and B using the strategy shown in Scheme C . 130 Addition of O-methylisourea 369 to enone 368 in N,N- dimethylformamide afforded dihydropyrimidine 370 in 79% yield. Subsequent treatment of

102 103 compound 370 with tetrabutylammonium fluoride afforded alcohol 371 in 90% yield. When alcohol 371 was treated with ammonium acetate in ammonia, the O-methylisourea moiety was converted to the guanidine which, upon treatment with triethylamine, afforded spiro aminal 372 in an overall 85% yield.

Scheme C. Snider's Strategy for the Synthesis of Crambines A and B.

OMe o o HZN ^ N H TBDMSO, OMe 3 6 9 N NH

CH3 (CH2 ) 1 CH jICH j), MeOzC k ^OTBDMS

3 6 8 370 (79%)

NH,

HNX. NH N ^ NH b,c CH3 (CHz)n » '- CH^CH^, MeOjjC MeOzC ^ ^OH

372 (85%) 371 (90%)

(a) n-Bu 4NF; (b) NH 4OAc, NH3; (c) Et3N.

The same strategy was applied to the synthesis of the guanidine containing central tricyclic core of ptilomycalin A .131 As shown in Scheme Cl, alkylation of the lithium anion of alkyne 373 with octanal afforded propargylic alcohol 374 in 92% yield.

Treatment of 374 with lithium aluminum hydride afforded diol 375 in 95% yield. Swern oxidation of diol 375 yielded compound 376 which was reacted with methyl 3-oxooctanoate in the presence of a catalytic amount of piperidine to afford 61% of compound 377 as a 1:1 mixture of stereoisomers. Condensation of O-methylisourea 369 on compound 377 afforded 104 Scheme Cl. Snider's Synthesis of the Internal Tricyclic Core of Ptilomycalin A

OTBDMS

OTBDMS HO.

OH 3 7 3 374 (92%)

O 377 (61%) 376 (94%)

OMe

HZNA NH 3 6 9

H H MeO. HO > I ‘ -Ns i> N^ ( CH2)4CH3 c h3(c h2)6'%*'| T

'C Q 2Me

378 (56%) 379 60%

(a) n-BuLi; (b) octanal; (c) LiAIH4; (d) (COCI)2. DMSO, Et 3N; (e) methyl 3-oxooctanoate, cat. piperidine; (f) NaHCOa; (g) NH4OAc, NH3.

56% of compound 378 as a 3:1 mixture of transxis isomers at C-io- Both isomers underwent cyclization when treated with ammonium acetate in ammonia to afford 60% of guanidine 379 with the right stereochemistry at C-io- Thus, this sequence constitutes a model study leading to the synthesis of the central portion of the natural product. Introduction of the appropriate 105 oxidation state in the methylene side-chalns early in the synthesis may provide a route to the

natural product.

C. Synthesis of an Advanced Tricyclic Intermediate en Route to the Total

Synthesis of Ptilomycalin A.

An enantioselective synthesis of an advanced intermediate en route to the total

synthesis of ptilomycalin A was reported in 1993 by Overman and coworkers .132 Their strategy

relied on the use of a tethered Biginelli condensation which afforded a hydropyrrolopyrimidone bicyclic system which was further elaborated into the desired tricyclic intermediate.

As shown in Scheme CM, reaction of enantiopure alcohol 380 with hydrazoic acid under

Mitsunobu conditions afforded azide 381 in 75% yield. Treatment of compound 381 with

lithium aluminum hydride followed by reaction with potassium isocyanate and hydrochloric acid yielded urea 382 in 82% yield. Ozonolysis of 382 afforded the intermediate hemiaminal 383.

Biginelli condensation of compound 383 with enantiopure p-ketoester 384 afforded cis hydropyrrolopyrimidone 385 in 42% yield, along with 8 % of the trans isomer 386. Compound

385 was treated with tetrabutylammonium fluoride to afford alcohol 387 in 95% yield.

Cyclization to spiro aminal 388 was accomplished in quantitative yield using a catalytic amount of p-toluenesulfonic acid in chloroform at room temperature. The stereochemistry of 388 was determined by NOE experiments. When this compound was heated with a catalytic amount of p-toluenesulfonic acid in methanol, a 2:1 mixture of separable isomers 389 and 388 was obtained. Further elaboration of the hydroxyethylene side-chain may lead to the total synthesis of ptilomycalin A. It is to be noted that this route is related to our approach to ptilomycalin A analog 16, discussed in chapter VI. Our approach involved carbon-carbon bond formation, followed by reduction. Overman's approach addressed the reduction step prior to carbon- carbon bond formation. 106 Scheme Cll. Synthesis of Tricyclic Intermediate 389

b ,C HN NH

MgG 2C MeQ 2C. > HO' 3 8 0 381 (75%) 382 (82%)

O O OTBDMS

HO MeO' 3 8 4 O ^ N H z NH OTBDMS

385 (c is: 42%) 3 8 3 386 (trans : 8 %)

HO HO

NH OTBDMS NH OH

3 8 5 387 (95%)

HO HO

NH NH Me Me

2:1

3 8 9 388 (100%)

(a) HN3, PPh3l DEAD; (b) LiAIH4; (c) HCI, KONC; (d) 0 3; Me 2S; (e) piperidine, HOAc; (f) /7-BU4NF; (g) cat. p-TsOH; (h) cat. p-TsOH, A. 107 D. Conclusion.

In conclusion, the research described in this thesis led to the synthesis of compound

14, a simple structural analog of ptilomycalin A. The structural features of compound 14 common with the natural product are a bicyclic guanidine moiety and the amido-alcohol portion,

or vessel subunit. The biological evaluation of compound 14 should provide us with interesting

structure-activity relationships. Incorporation of a spiro aminal moiety in compound 14 could

provide a better modelization of the structural features of ptilomycalin A.

Approaches to two other more elaborate structural analogs of ptilomycalin A have also

been discussed. Our approach to ptilomycalin A analog 15 led to the synthesis of compound

309 which could not be further elaborated. Our strategy for the synthesis of ptilomycalin A

analog 16 relied on an Eschenmoser sulfide contraction followed by ionic reduction of the

resulting double bond. Two diastereomers were obtained via this sequence and their

stereochemistry could not be ascertained. We were able to further elaborate those compounds

to bicyclic ureas 364 and 365 of potential synthetic interest for incorporation of the aminal

moiety. However, in light of Snider's elegant approach to ptilomycalin A and Overman's efficient

synthesis of tricycle 387, pursuing this project would require the design of a new approach for

the total synthesis of ptilomycalin A. CHAPTER VIII

EXPERIMENTAL

All melting points were taken with a Thomas-Hoover capillary melting point apparatus and are uncorrected as are all boiling points. Proton nuclear magnetic resonance spectra were recorded on Bruker AC-200, Bruker AM-250, Bruker WM-300, Bruker AC-300 or Bruker AC-500 spectrometers and are recorded in parts per million from internal chloroform, benzene, dimethylsulfoxide or water on the 5 scale. The 1H NMR spectra are reported as follows:

[multiplicity (s = singlet, d = doublet, t = triplet, q = quartet, p = pentet, m = multiplet, br = broad), coupling constants in hertz, integration, interpretation]. 13C NMR data were obtained with

Bruker AM-250, Bruker AC-300 or Bruker AM-500 spectrometers. Infrared spectra were taken with a Perkin-Elmer 1600 FTIR instrument. Optical rotation data were obtained using a Perkin-

Elmer 241 polarimeter at the sodium D line ( 1-mL sample cell) and are reported at 20°C. Mass spectra were obtained on a Kratos MS-30 or Kratos VG70-250S instrument at an ionization energy of 70 eV. Compounds for which exact mass is reported exhibited no significant peaks at m/e greater than that of the parent. Combustion analyses were performed by Atlantic Microlab,

Inc., Atlanta, Georgia.

Solvents and reagents were dried and purified prior to use when deemed necessary: tetrahydrofuran, benzene, toluene and diethyl ether were distilled from sodium metal; dichloromethane, dimethylsulfoxide, acetonitrile, methanol and A/,A/-dimethylformamide were distilled over calcium hydride. Diazomethane solutions were prepared from A/-methyl-A/- nitrosourea and used immediately .133 Reactions requiring an inert atmosphere were run under

108 109 argon. Analytical thin-layer chromatography was conducted using EM Laboratories 0.25 mm precoated silica gel 60F-254 plates. Column chromatography was performed over EM

Laboratories silica gel (70-230 mesh). Organometallic reagents (alkyllithiums) were titrated prior to use with menthol using 1,10-phenanthroline as the indicator .134 The order of experimental procedures follow their order of appearance in the text.

THPO-CH2 H

16 2

3-[(Tetrahydro-2W-pyran-2-yl)oxy]-1-propyne (162).135 To a mixture of 2.24 g (40.0 mmol) of 3,4-dihydro-2H-pyran and 80 pL of concentrated hydrochloric acid was added

3.62 g (43.0 mmol) of propargyl alcohol in three portions over 15 min. The reaction was exothermic and the temperature was kept between 50-60°C using a water bath during the addition. The mixture was stirred for 2 h, diluted with 10 mL of dichloromethane, washed with 20 mL of saturated aqueous sodium bicarbonate, dried (MgSCU) and concentrated in vacuo. The residue was purified by distillation under reduced pressure to afford 4.15 g (75%) of tetrahydropyranyl ether 162 as a colorless oil: bp 71-74°C (13 mm); 1H NMR (CDCI3, 250 MHz)

81.48-1.84 (m, 6H, CH2CH2CH2), 2.39 (t, J= 2.4 Hz, 1H, =CH), 3.47-3.56 (m, 1H, CH20), 3.77-

3.87 (m, 1H, CH 20), 4,24 (dd, J= 4.5, 2.4 Hz, 2H, CCH2), 4.80 (t, J= 3.1 Hz, 1H, OCHO).

THPO,

1 63

15-Bromo-1-[(tetrahydro*2H-pyran-2-yl)oxy]-2-pentadecyne (163).43 To a solution of 1.44 g (10.3 mmol) of tetrahydropyranyl ether 162 in 11 mL of tetrahydrofuran cooled to -78°C was added 7.11 mL (10.3 mmol) of n-butyllithium (1.45M solution in hexanes) 110 and 3.85 g (10.3 mmol) of dry hexamethylphosphoramide. The reaction mixture was stirred at room temperature for 2 h and was then added over 1 h, via an addition funnel, to a solution of

6.76 g (20.6 mmol) of 1,12-dibromododecane in 21 mL of tetrahydrofuran stirred at room temperature. The mixture was stirred an additional hour at room temperature and poured into a separatory funnel containing 60 mL of saturated aqueous ammonium chloride. This aqueous solution was extracted with four 25-mL portions of pentane. The combined organic extracts were washed with two 25-mL portions of water, dried (MgS04) and concentrated in vacuo. The residue was purified by chromatography over silica gel (eluted with pentane-ethyl acetate , 30:1) to afford 1.90 g (48%) of bromide 163 as a colorless oil: 1H NMR (CDCI 3 , 250 MHz) 51.20-1.90

(m, 26 H, CH2), 2.16-2.24 (m, 2H, CCCH2C), 3.40 (t, J = 7 Hz, 2H, CH2Br), 3.48-3.56 (m, 1H,

CH2O), 3.81-3.88 (m, 1H, CH 2 0 ), 4.16-4.32 (m, 2H, OCH2CC), 4.81 (m, 1H, OCHO).

1 6 4

l-Bromo-l5-[(tetrahydro-2/7-pyran-2-yl)oxy]pentadecane (164).43 A solution of 1.82 g (4.71 mmol) of alkyne 163 in 23 mL of ethyl acetate containing 15 mg of platinum oxide was hydrogenated in a Parr hydrogenator under 22 psi of hydrogen pressure for

3 h. The reaction mixture was filtered through Celite and concentrated in vacuo. The residue was purified by chromatography over silica gel (eluted with hexanes-ethyl acetate, 30:1) to afford 1.76 g (96%) of bromide 164 as a colorless oil: 1H NMR (CDCI 3 , 300 MHz) 81.26-2.17

(m, 32H, CH2), 3.33-3.38 (m, 1H, CH 2 0 ), 3.40 (t, J= 7Hz, 2H, CH2 Br), 3.45-3.53 (m, 1H,

CH20), 3.67-3.77 (m, 1H, CH20), 3.82-3.91 (m, 1H, CH20), 4.57 (m, 1H, OCHO). 111 THPO

165

l6-[(Tetrahydro-2H-pyran*2*yl)oxy]hexadecanenltrile (165).43 To a

solution of 1.71 g (4.38 mmol) of bromide 164 in 13 mL of a 33 % aqueous solution of sodium cyanide was added nine drops of tributylamine. The reaction mixture was heated at reflux for 24

h. Upon cooling, a solid precipitated. This material was collected, dissolved in 100 mL of

dichloromethane and the resulting solution was dried (MgSO^. The solvent was evaporated in

vacuo and the residue was purified by chromatography over silica gel (eluted with ethyl acetate-

hexanes, 1:9) to afford 1.27 g ( 86 %) of nitrile 165 as a white solid: mp 44-46°C; 1H NMR

(CDCI3, 250 MHz) 81.26 (s, 24H, CH2); 1.37-1.82 (m, 8 H, CH2), 2.32 (t, J = 7 Hz, 2H, CH2CN),

3.33-3.42 (m, 1H, CH20), 3.45-3.53 (m, 1H, CH20), 3.68-3.77 (m, 1H, CH20), 3.82-3.91 (m,

1H, CH20), 4.57 (m, 1H, OCHO); 13C NMR (CDCI3 , 62.9 MHz) 8 17.1 (t), 19.7 (t), 25.4 (t), 25.5

(t), 26.2 (t), 28.6 (t), 28.7 (t), 29.3 (t), 29.5 (t), 29.6 (t), 29.7 (t), 30.8 (t), 62.3 (t), 67.7 (t), 98.8 (d),

119.8 (S).

THPO' COOH

16 6

16-[(Tetrahydro-2H-pyran-2-yl)oxy]hexadecanolc acid (166). To a solution

of 1.12 g (3.32 mmol) of nitrile 165 in 66 mL of methanol was added 56 mL of 10 M aqueous

sodium hydroxide. The mixture was heated at reflux for 28 h, cooled in an ice bath, acidified to

pH 2 with concentrated hydrochloric acid and the resulting solution was extracted with four 100-

mL portions of ether. The combined organic extracts were washed with two 100-mL portions of water, dried (MgSC> 4) and concentrated in vacuo. The residue was purified by chromatography over silica gel (eluted with chloroform-methanol, 95:5) to afford 1.15 g (97%) of carboxylic acid

166 as a white solid: mp 50-52°C; IR (CHCI 3) 1709 cm’ 1; 1H NMR (CDCI 3 200 MHz) 81.25 (s. 112 28H, CH2), 1.53-1.82

3.45-3.56 (m, 1H, CH20), 3.67-3.79 (m, 1H, CH 20), 3.82-3.93 (m, 1H, CH 20), 4.57 (m, 1H,

OCHO); the acidic proton was not seen; 13C NMR (CDCI 3, 62.9 MHz) 519.7 (t), 24.7 (t), 25.5 (t),

26.2 (t), 29.1 (t), 29.2 (t), 29.4 (t), 29.5 (t), 29.6 (t), 29.7 (t), 30.8 (t), 34.0 (t), 62.3 (t), 67.7 (t),

98.8 (d), 179.2 (s); exact mass calcd. for C2i H 40O4 m/e 356,2927, found m/e 356.2890. Anal,

calcd for C2 iH 40O4 : C, 70.74; H, 11.31. found C, 70.78, H, 11.32.

q s

PhCHzO

171

Benzyl 2-thioxo-3-thiazolidinecarboxylate (171). To a solution of 1.88 g

(11.0 mmol) of benzyl chloroformate in 120 mL of tetrahydrofuran was added 1.19 g (10.0 mmol) of thiazolidine- 2-thione 170 and 1.52 g (15.0 mmol) of triethylamine. The resulting mixture was stirred at 50°C for 1 h and diluted with 500 mL of dichloromethane. This organic solution was washed successively with 150 mL of 10% aqueous hydrochloric acid and 150 mL of brine, dried

(MgS0 4 ) and concentrated in vacuo. The residue was purified by chromatography over silica gel (eluted with acetone-hexanes, 1 :2) to afford 2.17 g ( 86 %) of N-acyl thiazolidine 171 as a yellow solid: mp 73-76°C; 1H NMR (CDCI 3, 200 MHz) S 3.27 (t, J = 7.5 Hz, 2H, CH2SCS), 4.51

(t, J= 7.5 Hz, 2H, CH2NCS), 5.29 (s, 2H, CH 2 Ph), 7.34-7.46 (m, 5H, Ph); 13C NMR (CDCI 3 ,

62.9 MHz) 8 28.3 (t), 55.6 (t), 69.2 (t), 128.5 (d), 128.6 (d), 128.7 (d), 134.6 (s), 151.0 (s), 199.6

(s). 113

0 ^ ,0 C H 2Ph ,N*.. O HNW y v > N NOCHoPh I H

172

[3-[[4-(Carboxyamlno)butyl]amino]propyl]carbamic acid, dibenzyl ester

(172). To a solution of 2.42 g (16.6 mmol) of spermidine 168 in 70 mL of dichloromethane

stirred at room temperature was added dropwise over 1.5 h a solution of 7.00 g (27.6 mmol) of 3-

(carboxybenzyl)thiazolidine-2-thione 171 in 28 mL of dichloromethane. The mixture was stirred

at room temperature for 1.5 h and concentrated in vacuo to afford a white solid. The apolar thiazolidine- 2-thione was removed by filtration through a short pad of silica gel (eluted with

dichloromethane-methanol, 10:1) to yield a white solid. It was recrystallized from ethyl acetate-

hexanes to afford 2.84 g (52%) of amine 172 as a white solid: mp 103-105°C; IR (CHCI 3) 3451,

1713,1517 cm’1; 1H NMR (CDCI3, 300 MHz) 8 1.48-1.60 (m, 5H, CH2, NH), 1.62-1.72 (m, 2H,

CH2), 2.58 (t, J = 6.5 Hz, 2H, CH 2NH), 2.66 (t, J= 7.0 Hz, CH2N), 3.12-3.20 (m, 2H, CH2NCO),

3.24-3.32 (m, 2H, CH2NCO), 5.08 (s, 4H, CH 20), 5.18 (brs, 1H, NH), 5.51 (brs, 1H, NH), 7.32-

7.42 (m, 10H, Ph); 13C NMR (CDCI 3 , 62.9 MHz) 27.3 (t), 27.7 (t), 29.5 (t), 39.8 (t), 40.9 (t), 47.6

(t), 49.3 (t), 66.4 (t), 128.0 (d), 128.3 (d), 128.4 (d), 136.7 (s). 136.8 (s), 156.5 (s); exact mass calcd. for C i 2H 17N20 2 (M-ChHhN02) m/e 221.1282, found m/e 221.1281 and for

C i3H-|gN20 2 (M- C10H i2NO2) m/e235.1438, found 214.1448. Anal, calcd. for 0 ^ 3^ 3 0 4 :

C, 66.80; H, 7.56. found C, 66.75; H, 7.61. 114

THPO NX.OCH2Ph H

1 73

[3-[N-[4-(Carboxyamlno)butyl]-16-[(tetrahydro-2H-pyran-2-yl)oxy]

hexadecanamide]propyl]carbamic acid, dibenzyl ester (173). To a solution of 1.07

g (3.0 mmol) of carboxylic acid 166 and 1.24 g (3.0 mmol) of amine 172 in 54 mL of tetrahydrofuran was added 0.618 g (3.0 mmol) of dicyclohexylcarbodiimide and 42 mg (0.3

mmol) of 1-hydroxybenzotriazole. The reaction mixture was stirred at room temperature for 27 h, filtered and concentrated in vacuo. The residue was purified by column chromatography over

50 g of silica gel (eluted with 600 mL of ethyl acetate-hexanes, 1:1 then 700 mL of ethyl acetate-

hexanes, 2:1) to afford 2.17 g (95%) of amide 173 as a colorless oil: IR (neat) 3327, 1721,

1628, 1534 cm'1; 1H NMR (DMSO-d 6 at 373K, 250 MHz) 5 1.29 (s, 23H, CH2), 1.48-1.54 (m,

11H, CH2), 1.65-1.74 (m, 4H, CH2) 2.25 (t, J= 7.2 Hz, 2H, CH2CO), 3.01-3.10 (m, 4H, CH2N),

3.22-3.31 (m, 4H, CH2NH), 3.34-3.47 (m, 2H, CH20), 3.59-3.68 (m, 1H, CH 20), 3.75-3.82 (m,

1H, CH20), 4.55 (m, 1H, OCHO), 5.06 (s, 4H, CH2Ph), 6.80 (br s, 2H, NH), 7.30-7.37 (s, 10H,

Ph); 13C NMR (DMSO-d 6 at 373K. 62.9 MHz) 6 18.7 (t), 24.4 (t), 25.1 (t), 26.4 (t), 28.2 (t), 28.27

(t), 28.31 (t), 28.7 (t), 29.9 (t), 31.7 (t), 37.8 (t), 60.9 (t), 64.68 (t), 64.74 (t), 66.2 (t), 97.6 (d),

126.9 (d), 127.0 (d), 127.6 (d), 136.8 (s), 155.5 (s), 171.3 (s); mass spectrum (FAB) m/e (relative intensity) 751.7 (M+, 1.99), 668.5 (100). 115

N A OCH2Ph H

1 7 4

[3-[A/-[4-(Carboxyamino)butyl]~16*hydroxyhexadecanamide]propyl]car- bamlc acid, dibenzyl ester (174). To a solution of 1.90 g (2.85 mmol) of amide 173 in 40 mL of methanol was added 400 mg of acidic Dowex-50 resin. The mixture was stirred at room temperature for 8 h and filtered. The filtrate was concentrated in vacuo to afford a white solid.

Recrystallization from ethyl acetate-hexanes afforded 1.46 g (87%) of alcohol 174 as a white solid: mp 75-76.5°C; IR (CHCI3) 3684, 3624, 3452, 1715, 1625 cm*1; 1H NMR (DMSO-d 6 at

363K, 250 MHz) 81.28 (s, 20H, CH2), 1.43-1.53 (m, 10H, CH2), 1.65-1.70 (m, 2H, CH2), 2.25 (t,

J= 7.2 Hz, 2H, CH2CO), 3.03-3.10 (m, 5H, NCH2 and OH), 3.22-3.30 (m, 4H, NCH2), 3.43 (t, J=

6.3 Hz, 2H, CH20), 5.06 (s, 4H, CH2Ph), 6.86 (br s, 2H, NH), 7.31-7.37 (m, 10H, Ph); 13c NMR

(DMSO-d6 at 373K, 62.9 MHz) 8 24.5 (t), 24.9 (t), 26.4 (t), 28.2 (t), 28.3 (t), 31.7 (t), 32.0 (t), 37.8

(t), 60.4 (t), 64.7 (t), 64.8 (t), 126.9 (d), 127.0 (d), 127.6 (d), 128.9 (d), 136.8 (s), 136.9 (s),

153.9 (s), 155.5 (s), 171.3 (s); mass spectrum (FAB) m/e (relative intensity) 668.5 (M++1,100).

Anal, calcd. for C 39 H61N30 6: C, 70.13; H, 9.21. found C, 69.53; H, 9.16. 116

,c o c f 3

THPO N A,COCF3 ~ f * V N 14 o H

1 7 5

16-[(Tetrahydro-2H-pyran-2-yl)oxy]-A/-[4-(2,2,2-trlfluoroacetamido)butyl]-N-[3-(2,2,2-trifluoroacetamido)propyl]hexadecanamide acetate (ester)

(175). A solution of 200 mg (0.27 mmol) of amide 173 in 5 mL of anhydrous ethanol was degassed with argon for 10 min. Palladium hydroxide on carbon (40 mg) was added and the suspension was hydrogenated using a Parr apparatus at 50 psi for 6 h. The catalyst was removed by filtering the mixture through a glass frit. The filtrate was evaporated to dryness and proton NMR analysis of the residue showed that hydrogenolysis of both benzyl carbamates had occured. To a solution of the residual diamine in 2.6 mL of dichloromethane stirred at 0°C was added 65 pL (0.8 mmol) of pyridine and 79 pL (0.56 mmol) of trifluoroacetic anhydride. The mixture was stirred at 0°C for 10 min, at room temperature for 2.5 h and concentrated in vacuo.

The residue was purified by column chromatography over 20 g of silica gel (eluted with ethyl acetate-hexanes, 1:1) to yield 110 mg (65%) of bis-trifluoroacetamide 175 as a pale yellow oil:

IR (neat) 3289,1722,1628 cm'1; 1H NMR (DMSO-d 6 at 373K, 250 MHz) 8 1.29 (s, 24H, CH2),

1.48-1.55 (m, 12H, CH2), 1.63-1.82 (m, 2H, CH2), 2.27 (t, J= 7.2 Hz, 2H, CH2CO), 3.19-3.33

(m, 8 H, NCH2) 3.37-3.50 (m, 2H, CH20), 3.58-3.68 (m, 1H, CH 20), 3.75-3.82 (m, 1H, CH20),

4.56 (m, 1H, OCHO), 9.05 (brs, 2 H, NH); 13C NMR (DMSO-d6 at 373K, 125.7 MHz) 5 18.8 (t),

24.6 (t), 24.7 (t), 25.3 (t), 28.3 (t). 28.5 (t), 28.8 (t), 30.0 (t), 31.8 (t), 36.7(f), 38.6 (t), 42.5 (t),

44.6 (t), 46.8 (t), 61.0 (t), 66.3 (t), 97.7 (d), 156.2 (4s), 171.8 (S); 19F NMR (DMSO-d 6, 235.4

MHz) 8 -112.17, -112.15, -112.13, -112.06; exact mass calcd. for C 3 2H5 sN3 0 5 F6 m/e

675.4049, found m/e 675.4039. 117

,c o c f 3

HO ~ f14 * Vo

17 6

16-Hydroxy-W-[4-(2, 2, 2-trifluoroacetamldo)butyl]-A/-[3-(2,2,2- trlfluoroacetamido)propyl]hexadecanamide acetate (ester) (176). To a solution of

88 mg (0.13 mmol) of tetrahydropyranyl ether 175 in 2 mL of methanol was added 10 mg of acidic Dowex-50 resin. The mixture was stirred at room temperature for 6 h, filtered and concentrated in vacuo. The residue was purified by column chromatography over 5 g of silica gel (eluted with ethyl acetate-hexanes, 2:1) to afford 77 mg (100%) of alcohol 176 as a white solid: mp 102-103°C; IR (neat) 3346,1716,1624 cm’1; 1H NMR (DMSO-d 6 at 373K, 250 MHz)

8 1.30 (S, 22H, CH2), 1.44-1.57 (m, 8 H, CH2), 1.78 (q, J = 7.2 Hz, 2H, CH2),2.28 (t, J = 7.2 Hz,

2H, CH2CO), 3.21-3.34 (m, 8 H, NCH2), 3.44 (t, J= 6.4 Hz, 2H, CH2OH), 3.82 (br s, 1H, OH),

8.99 (brs, 2H, NH); 13C NMR (DMSO-d 6 at 373K, 125.8 MHz) 524.6 (t), 25.1 (t), 25.3 (t), 26.5

(t), 27.6 (t), 28.3 (t), 28.4 (t), 28.5 (t), 31.8 (t), 32.1 (t), 36.7 (t) 38.6 (t), 42.3 (t), 44.3 (t), 46.6 (t),

60.5 (t), 112.2 (s), 114.5 (S), 116.7 (s), 119.0 (s), 155.5 (s), 155.8 (S), 156.1 (S), 156.3 (s), 171.6

(s); exact mass calcd. for C 27H47N3O4F6 m/e 591.3473,, found m/e 591.3409. Anal, calcd. for

C27H47N3O4F6: C, 54.81; H, 8.01; N, 7.10. found C, 54.72; H, 8.03; N, 7.12. 118

16-Acetoxy-A/-[4-(2,2,2*trifluoroacetamldo)butyl]-W-[3-(2,2,2-trifluoro* acetamldo)propyl]hexadecanamlde acetate (ester) (7) To a solution of 74 mg (0.125 mmol) of alcohol 176 in 2 mL of dichloromethane was added 16 pL (0.188 mmol) of pyridine and 14 pL (0.138 mmol) of acetic anhydride. The mixture was stirred at room temperature for 14 h and concentrated in vacuo. The oily residue was purified by column chromatography over 5 g of silica gel (eluted with ethyl acetate-hexanes, 1:1) to afford 55 mg (70%) of acetate 7 as a pale yellow oil: IR (neat) 3301,1728,1714,1633 cm'1; 1H NMR (DMSO-d 6 at 373K, 250 MHz) 51.30

(s, 22H, CH2), 1.47-1.63 (m, 8 H, CH2), 1.77 (q, J= 7.2 Hz, 2 H, CH2), 2.00 (s, 3H, CH3CO), 2.28

(t, J= 7.2 Hz, 2H, CH2CO), 3.21-3.34 (m, 8 H, NCH2), 4.03 (t, J= 6.6 Hz, 2H, CH20), 9.00 (brs,

2H, NH); 13C NMR (DMSO-d6 at 373K) 820.1 (q), 24.6 (t), 24.9 (t), 25.3 (t), 27.7 (t), 28.1 (t),

28.4 (t), 28.5 (t), 31.8 (t), 36.7 (t), 38.6 (t), 42.5 (t), 44.6 (t), 47.2 (t), 63.4 (t), 157.0 (4s), 170.0

(S), 171.8 (s): 19F NMR (DMSO-d6, 235.4 MHz) 8 -112.22, -112.20, -112.19, - 112.12 ; mass spectrum (FAB) m/e (relative intensity) 634.5 (M++1,65.1), 147 (100).

r- ■COOH

1 8 5

P.P’-Dibrom oisobutyric acid (185).54 A solution of 54.7 g (0.248 mol) of diethyl bis(hydroxymethyl)malonate 184 in 430 mL of 48% aqueous hydrobromic acid was placed in a one-neck one-liter round-bottomed flask attached to a simple distillation apparatus and heated 119 for 6 h at 120°C. About 150 mL of distillate was collected during this time. The cooled undistilled concentrate was poured into a 500-mL Erlenmeyer flask and placed in the freezer overnight. The precipitated white solid was collected on a fritted glass and dried in vacuo to afford 31.2 g (51%) of carboxylic acid 185 as an off-white solid: 1H NMR (CDCI 3, 200 MHz) 5

3.26 (p, J = 5.6 Hz, 1H, CHC02), 3.69-3.85 (m, 4H, CH 2Br), 9.64 ( brs, 1H, OH).

COOEt

186

Ethyl p.P'-dibrom oisobutyrate (186).55 To a solution of 28.66 g (0.116 mol) of p.p'-dibromoisobutyric acid 185 in 118 mL of benzene was added 40 mL of ethanol and 2.7 mL of concentrated sulfuric acid. The flask was attached to a Dean-Stark apparatus and the mixture was heated at reflux for 24 h and concentrated in vacuo. The residue was diluted with 150 mL of water, neutralized by addition of solid sodium bicarbonate and extracted with four 180-mL portions of diethyl ether. The combined organic extracts were dried (MgS 0 4 ) and concentrated in vacuo. The crude brown oil was purified by distillation under reduced pressure to afford

20.04 g (63%) of ester 186 as a colorless oil: bp 68-72°C (0.25 mm) (lit .55 84-86°C (2.5 mm));

1H NMR (CDCI3, 200 MHz) 51.29 (t, J= 7.1 Hz, 3H, CH 3), 3.16 (p, J= 5.3 Hz, 1H, CHCO), 3.66-

3.82 (m, 4H, CH 2Br), 4.23 (q, J= 7.1 Hz, 2H, CH20); 13C NMR (CDCI3 , 62.9 MHz) 6 14.1 (q),

30.5 (t), 48.7 (d), 61.7 (d), 169.5 (s).

COOEt

182

Ethyl 2-brom om ethylacrylate (182).54 To a solution of 23.10 g (84.3 mmol) of ester in 55 mL of benzene stirred at room temperature was added dropwise over 1 h a solution 120 of 8.54 g (84.3 mmol) of triethylamine in 55 mL of benzene. The resulting white suspension was stirred at room temperature for 1 h, heated at reflux for 1 h, cooled to room temperature and filtered. The filtrate was concentrated in vacuo. The yellow crude oil was purified by distillation under reduced pressure to afford 12.10 g (75%) of acrylate 182 as a colorless oil: bp 58-61°C

(5 mm)(lit.54 bp 44-45°C (1.7 mm)); 1H NMR (CDCI3i 200 MHz) 81.30 (t, J= 7.1 Hz, 3H, CH3),

4.15 (s, 2H, CH2Br), 4.24 (q, J= 7.1 Hz, 2H, CH20), 5.91 (s, 1H, =CH), 6.29 (s, 1H, =CH).

COOEt * Ph^ ^NH H IV ^Ph

18 7

N-Benzyl-2-[(benzylamino)methyl]-p-alanlne, ethyl ester (187). To a solution of 0.343 g (3.2 mmol) of benzylamine in 2 mL of chloroform stirred at 0°C was added dropwise over 30 min a solution of 0.193 g (1.0 mmol) of ester 182 in 3 mL of chloroform. The mixture was stirred at room temperature for 6.5 h, at 50°C for 11 h, cooled to room temperature, diluted with 50 mL of dichloromethane and washed with 20 mL of 1 M aqueous sodium hydroxide. The aqueous wash was saturated with sodium chloride and extracted with three 15- mL portions of ethyl acetate. The combined organic extracts were dried (MgSCU) and concentrated in vacuo. The residue was purified by column chromatography over 30 g silica gel

(eluted with dichloromethane-methanol, 30:1 then 20:1) to afford 0.238 g (73%) of diamine

187 as a pale yellow oil: IR (neat) 3333,1727,1603 cm-1; 1H NMR (CDCI3, 250 MHz) 81.26 (t, J

= 7.1 Hz, 3H, CH3), 1.84 (br s, 2H, NH), 2.81-2.95 (m, 5H, CH 2N, CH20), 3.79 (s, 4H, CH 2Ph),

4.17 (q, J= 7.1 Hz. 2 H, CH2OCO), 7.22-7.35 (m, 10H, ArH); 13C NMR (CDCI3,, 62.9 MHz) 8

14.2 (q), 45.9 (d), 49.3 (t), 53.7 (t), 60.5 (t), 126.9 (d), 128.0 (d), 128.4 (d), 139.9 (s), 174.2 (S); exact mass calcd. for C 2qH26N20 2 m/e 326.1994, found m/e 326.1996. COOEt 121

1 8 8

Ethyl 1,3-dlbenzylhexahydro-2-oxo-5-pyrimidlnecarboxylate (188). To a

solution of 1.97 g (6.04 mmol) of diamine 187 in 25 mL of benzene was added 1.96 g (12.1

mmol) of carbonyldiimidazole. The mixture was heated at reflux for 40 h and concentrated in

vacuo. The crude oil was purified by column chromatography over 50 g silica gel (eluted with

ethyl acetate-hexanes, 1:3) to afford 1.61 g (73%) of urea 188 as a pale yellow oil: IR (neat)

1733,1638 cm'1; 1H NMR (CDCI 3 , 300 MHz) 8 1.15 (t, J= 7.1 Hz, 3H, CH3), 2.87*2.96 (m, 1H,

CHCO), 3.34-3.40 (dd, J= 11.7, 5.1 Hz, 2H, CH2N), 3.41-3.47 (dd, J = 11.7, 8.1 Hz, 2H, CH 2N),

4.04 (q, J= 7.1 Hz, 2H, CH2OCO), 4.58 (d, J = 15.0 Hz, 2H, CH 2Ph), 4.68 (d, J= 15.0 Hz, 2H,

CH2Ph), 7.24-7.37 (m, 10H, ArH); 13C NMR (CDCI 3, 62.9 MHz) 8 14.0 (q), 38.1 (d), 46.5 (t),

51.7 (t), 61.2 (t), 127.2 (d), 128.0 (d), 128.5 (d), 138.1 (s), 155.7 (s), 170.5 (s); exact mass calcd. for C2iH 24N20 3 m/e 352.1788, found m/e 352.1763.

COOEt

1 89

Ethyl 1-benzylhexahydro-2-oxo-5-pyrimidinecarboxylate (189). A solution of 1.76 g (5.0 mmol) of urea 188 in 25 mL of 48% aqueous hydrobromic acid was heated at reflux for 16 h and the solvent was removed by azeotroping with ethanol. The residue was purified by column chromatography over silica gel (eluted with dichloromethane-methanol, 30:1) to afford 0.761 g (60%) of urea 189 as a white solid: mp 117-119°C; IR (CHCI 3) 3235,1748 cm' 122 1; 1H NMR (CDCI3, 200 MHz) 5 1.19 (t, J = 7.1 Hz, 3H, CH3), 2.85-2.98 (m, 1H, CHCO), 3.29-

3.42 (m, 2 H, CH2NH), 3.46-3.53 (m, 2H, CH2N), 4.02-4.18 (dq, J = 7.1, 2.7 Hz, 2H, CH 2OCO),

4.48 (d, J= 15.2 Hz, 1H, CH2 Ph), 4.61 (d, J= 15.2 Hz, 1H, CH2Ph), 5.67 (brs, 1H, NH), 7.21-

7.37 (m, 5H, ArH); 13C NMR (CDCI3 , 62.9 MHz) 8 14.0 (q), 38.1 (d), 41.9 (t), 46.1 (t), 50.8 (t),

61.2 (t), 127.2 (d), 127.9 (d), 128.5 (d), 137.6 (s), 156.0 (s), 170.5 (s); exact mass calcd. for

C i4H i8 N20 3 m/e 262.1317, found m/e 262.1315.

COOEt

1 9 0

Ethyl 1-benzyltetrahydro-2(l//)-thioxo-5-pyrim(dinecarboxylate (190).

To a solution of 761 mg (2.90 mmol) of urea 189 in 10 mL of toluene was added 1.409 g (3.48 mmol) of Lawesson’s reagent .136 The mixture was heated at reflux for 20 h and concentrated in vacuo. The solid residue was purified by chromatography over 20 g of silica gel (eluted with acetone-hexanes, 1:3) to yield 661 mg (82%) of thiourea 190 as a white solid: mp 136.5-

138.5°C; IR (CHCI 3) 3417,1738,1644,1542cm-1; 1H NMR (CDCI 3 , 200 MHz) 81.20 (t, J= 7.1

Hz, 3H, CH3), 2.99 (p, J= 6.9 Hz, 1H, CHCO), 3.40-3.55 (m, 4H, CH 2N), 4.03-4.19 (dq, J= 7.1,

3.7 Hz, 2H, CH2OCO), 5.08 (d, J= 15.0 Hz, 1H, CH2Ph), 5.28 (d, 15.0 Hz, 1H, CH 2Ph), 6.63

(brs, 1H, NH), 7.24-7.41 (m, 5H, ArH); 13C NMR (CDCI 3, 62.9 MHz) 8 14.0 (q), 37.1 (d), 42.4 (t),

46.7 (t), 57.3 (t), 61.6 (t), 127.7 (d), 127.9 (d), 128.6 (d), 136.2 (s), 169.8 (s), 178.4 (s); exact mass calcd. for C i 4 H is N 2 0 2S m/e 278.1090, found m/e 278.1086. Anal, calcd. for

C i4H i8 N20 2S: C, 60.40; H, 6.52. found C, 60.49; H, 6.57. COOEt 123

191

Ethyl 1-benzyl-2-mercaptan-5-carboxylatetetrahydro-2(l H )-A 1 -pyrlmldl*

nium iodide (191). To a solution of 344 mg (1.20 mmol) of thiourea 190 in 1.6 mL of

methanol was added 75 pL of iodomethane. The mixture was heated at reflux for 1 h and concentrated in vacuo to afford a yellow foam, which was recrystallized from methanol-ether to yield 429 mg (85%) of salt 191 as a pale yellow solid: mp 119.5-120.5°C; IR (CH 2CI2) 3443,

1731,1604 cm’1; 1H NMR (CDCI3 , 200 MHz) 8 1.26 (t, J= 7.1 Hz, 3H, CH3), 3.08 (s, 3H, CH 3S),

3.05-3.20 (m, 1H, CHCO), 3.62 (d, 6.1 Hz, 2H, CH2NH), 3.83 (dd, J = 14.0, 7.3 Hz, 1H,

CH2N), 4.09-4.23 (m, 3H, CH2N and CH 20), 4.72 (d, J= 15.9 Hz, 1H, CH 2Ph), 4.86 (d, J= 15.9

Hz, 1H, CH2Ph), 7.18-7.28 (m, 2H, ArH), 7.34-7.47 (m, 3H, ArH), 9.50 (brs, 1H, NH); 13C NMR

(CDCI3 , 62.9 MHz) 8 14.1 (q), 17.3 (q), 35.4 (d), 42.0 (t), 48.7 (t), 57.2 (t), 62.2 (t), 127.6 (d),

129.1 (d), 129.4 (d), 132.3 (s), 165.7 (s), 169.0 (s); exact mass calcd. for C 15H21N2O2S (M+-I- )

m/e 293.1325, found m/e 293.1297. Anal, calcd. for C 15H21N2O2SI: C, 42.86; H, 5.04. found

C, 42.97; H, 5.06.

CH-pH

19 9

1,3-Dibenzyl-5-(hydroxymethyl)hexahydro-2*pyrimidinone (199). To a so lution of 1.81 g (5.13 mmol) of ester 188 in 10 mL of methanol chilled in an ice bath was added in four portions over 30 min 409 mg (10.26 mmol) of sodium borohydride. The mixture was 124 stirred at room temperature for 20 h and the excess reducing agent was quenched by addition of 20 mL of water. The mixture was neutralized to pH 7 by addition of 1 M aqueous hydrochloric acid and extracted with two 40-mL portions of ethyl acetate. The combined organic extracts were dried (MgSCU) and concentrated in vacuo. The residue was purified by column chromatography over 50 g of silica gel (eluted with dichloromethane-methanol, 30:1) to yield

I.38 g ( 86 %) of alcohol 199 as a white solid: mp 85.5-87°C; IR (CH 2CI2) 3372,1612,1514 cnr

1; 1H NMR (CDCI3, 300 MHz) 81.91 (t, J= 5.2 Hz, 1H, OH), 2.04-2.19 (m, 1H, CH), 3.00 (dd, J=

II.8 , 7.9 Hz, 2H, CH 2N), 3.23 (dd, ./= 11.8,4.7 Hz, 2H, CH 2N), 3.42 (dd, J= 6.6 , 5.3 Hz, 2H,

CH20), 4.51 (d, J= 15.0 Hz, 2H, CH2Ph), 4.63 (d, J= 15.0 Hz, 2H, CH2Ph), 7.22-7.35 (m, 10H,

ArH); 13C NMR (CDCI3 , 62.9 MHz) 8 34.2 (d), 47.1 (t), 51.3 (t), 61.5 (t), 126.9 (d), 127.4 (d),

128.2 (d), 137.9 (s), 156.0 (s); exact mass calcd. for CigH 22N20 2 m/e 310.1683, found m/e

310.1672. Anal, calcd. for C i 9 H22N20 2: C, 73.52; H, 7.15. found C, 73.25; H, 7.18.

CHjOTBDMS

200

1,3-Dibenzyl-5[(ter/-butyldfmethylsiloxy)methyl]hexahydro-2-pyrimidinone (200). To a solution of 556 mg (1.79 mmol) of alcohol 199 in 3 mL of /V,A/- dimethylformamide was added 305 mg (4.48 mmol) of imidazole and 418 mg (2.69 mmol) of tert- butyldimethylsilyl chloride. The reaction mixture was stirred at 35°C for 1 h, diluted with 30 mL of dichloromethane and washed with 10 mL of water. The aqueous wash was extracted with two

10-mL portions of dichloromethane. The combined organic extracts were dried (MgSCU) and concentrated in vacuo. The residue was purified by column chromatography over 20 g of silica gel (eluted with ethyl acetate-hexanes, 1:3) to afford 662 mg (87%) of silyl ether 200 as a pale yellow oil: IR (neat) 1637,1504 cm'1; 1H NMR (CDCI 3, 75.5 MHz) 8 -0.05 (s, 6 H, Si(CH3)2), 0.81 125 (s, 9H, C(CH 3)3), 2.08-2.19 (m, 1H, CH), 3.01 (dd, J= 11.7, 8.3 Hz, 2H, CH 2N), 3.20 (dd, J =

11.7,4.7 Hz, 2H, CH2N), 3.44 (d, J= 6.5 Hz, 2H, CH20), 4.53 (d, J= 15.0 Hz, 2H, CH2Ph),4.68

(d, J= 15.0 Hz, 2H, CH2Ph), 7.23-7.36 (m, 10H, ArH); 13C NMR (CDCI 3 , 75.5 MHz) 8 -5.6 (q),

8.1 (s), 25.8 (q), 34.9 (d), 47.2 (t), 51.7 (t), 62.7 (t), 127.1 (d), 128.0 (d), 128.5 (d), 138.5 (s),

156.3 (s); exact mass calcd. for C25H36N20 2Si m/e 424.2548, found m/e 424.2525.

CHaOTBDPS

Ph.

201

1,3-Dibenzyl>5[(ferf-butyldfphenylsiloxy)methyl]hexahydro-2-pyrimidinone (201). To a solution of 1.234 g (3.98 mmol) of alcohol 199 in 12 mL of N,N- dimethylformamide was added 406 mg (5.97 mmol) of imidazole and 1.27 mL (4.77 mmol) of ferf-butyldiphenylsilyl chloride. The reaction mixture was stirred at room temperature for 19 h, diluted with 80 mL of dichloromethane and washed with 80 mL of water. The aqueous wash was extracted with three 40-mL portions of dichloromethane. The combined organic extracts were dried (MgSCfy) and concentrated in vacuo. The residue was purified by column chromatography over 40 g of silica gel (eluted with ethyl acetate-hexanes, 1:4) to afford 1.575 g (72%) of silyl ether 201 as a pale yellow viscous oil: IR (neat) 1635,1504 cm*1; 1H NMR (CDCI 3, 250 MHz) 5

0.97 (s, 9H, C(CH3)3), 2.05-2.23 (m, 1H, CH), 3.00 (dd, J= 11.6, 8.6 Hz, 2H, CH2N), 3.19 (dd, J

= 11.6, 4.7 Hz, 2H, CH2 N), 3.50 (d, J= 6.6 Hz, 2H, CH20), 4.50 (d, J = 15.0 Hz, 2H, CH2Ph),

4.67 (d, J= 15.0 Hz, 2H, CH2 Ph), 7.22-7.46 (m, 16H, ArH), 7.51-7.55 (m, 4H, ArH); 13C NMR

(CDCI3, 62.9 MHz) 5 9.1 (s), 26.7 (q), 34.7 (d), 47.0 (t), 51.5 (t), 63.3 (t), 127.0 (d), 127.6 (d),

127.9 (d), 128.4 (d), 129.7 (d), 135.3 (d),138.0 (s), 138.3 (s), 156.1 (s); exact mass calcd. for

C3sH4oN20 2Si m/e 548.2850, found m/e 548.2856. CHjOTBDPS 1 26

r S PtV ^NV .NH T o

202

1-Benzyl-5-[(ferf-butyldiphenylsiloxy)methyl]tetrahydro-2(lH)-pyrimidl- none (202). To a solution of 515 mg (0.94 mmol) of urea 201 in 8 mL of tetrahydrofuran and

20 mL of ammonia stirred at -45°C was added sodium metal in small pieces until the mixture color stayed blue for 30 min. The mixture was quenched by addition of solid ammonium chloride and the ammonia was allowed to evaporate over 2 h. The solution was filtered, dried (MgS 0 4 ) and concentrated in vacuo. The crude oil was purified by column chromatography over silica gel

(eluted with dichloromethane-methanol, 2 0 :1) to afford 261 mg (61%) of urea 202 as a white solid: IR (neat) 3223, 1660, 1650 cn r1; 1H NMR (CDCI 3 , 250 MHz) 5 1.03 (s, 9H, C(CH3)3),

2.20-2.26 (m, 1H, CH), 3.00 (dd, J = 11.7, 8.4 Hz, 1H, CH 2 N), 3.10-3.21 (m, 2H, CH2N), 3.33-

3.40 (m, 1H, CH2N), 4.61 (d, J= 6.5 Hz, 2H, CH20), 4.45 (d, J= 15.0 Hz, 1H, CH2Ph), 4.61 (d, J

= 15.0 Hz, 1H, CH2 Ph), 5.28 (br s, 1H, NH), 7.23-7.30 (m, 6H, ArH), 7.32-7.47 (m, 5H, ArH),

7.58-7.61 (m, 4H, ArH); 13C NMR (CDCI3, 75.5 MHz MHz) 519.1 (s), 26.7 (q), 34.8 (d), 42.4 (t),

46.6 (t), 50.7 (t), 63.3 (t), 127.1 (d), 127.7 (d), 127.9 (d), 128.4 (d), 129.7 (d), 133.1 (s), 135.4

(d), 137.9 (s), 156.4 (s); exact mass calcd. for C 2sH34N20 2Si m/e 458.2390, found m/e

458.2399.

2 0 3

3-(Benzyloxy)-1-propanol (203).64 To a hot solution (115-120°C) of 10 g (134 mmol) of 1,3-propanediol in 8 mL of dry xylenes was added 1.0 g (43.5 mmol) of sodium in small pieces over 30 min. Benzyl chloride (6 g, 47.4 mmol) was then added dropwise over 20 min. 127 The mixture was heated at reflux for 15 min, cooled to room temperature and filtered. The filtrate was concentrated in vacuo and the residue was purified by distillation under reduced pressure to afford 4.14 g (57%) of alcohol 203 as a colorless oil: bp 75-78°C (0.05 mm); 1H NMR (CDCI 3 ,

200 MHz) 5 1.86 (p, J= 6.0 Hz, 2H, CH2), 2.66 (br s, 1H, OH), 3.65 (t, J = 6.0 Hz, 2 H, CH20),

3.77 (t, J= 6.0 Hz, 2H, CH20), 4.52 (s, 2H, CH2Ph), 7.22-7.45 (m, 5H, ArH).

2 0 4

3-(Benzyloxy)-1-propylbrom ide (204).65 To a mixture of 4.14 g (26.6 mmol) of alcohol 203 and 6.98 g (26.6 mmol) of triphenylphosphine chilled in an ice bath was added

4.74 g (26.6 mmol) of AZ-bromosuccinimide in portions over 20 min. The mixture was stirred at room temperature for 30 min and the precipitated triphenylphosphine oxide was removed by filtration and washed with 70 mL of benzene. The filtrate was washed with 60 mL of 0.5 M aqueous sodium bisulfite, two 100-mL portions of 0.5 M aqueous sodium hydroxide, 60 mL of brine, dried (MgSC> 4) and concentrated in vacuo. The semi-solid residue was triturated with 150 mL of diethyl ether. The ethereal extract was concentrated in vacuo to afford a yellow crude oil which was purified by column chromatography over 80 g of silica gel (eluted with hexanes- dichloromethane 4:1) to afford 2.76 g (45%) of bromide 204 as a colorless oil: 1H NMR (CDCI 3,

200 MHz) 5 2.15 (p, J= 6.1 Hz, 2 H, CH2), 3.65 (t, J= 6.5 Hz, 2H, CH2Br), 3.62 (t, J= 5.9 Hz, 2H,

CH20), 4.53 (S, 2H, CH2 Ph), 7.31-7.37 (m, 5H, ArH).

2 0 5

3-(Benzyloxy)-1-propyliodide (205). To a solution of 1.77 g (7.72 mmol) in 26 mL of acetone was added 4.63 g (30.9 mmol) of sodium iodide. The mixture was heated at 128 reflux for 20 h, cooled and partitioned between 50 mL of water and 100 mL of diethyl ether. The organic layer was washed with two 50-mL portions of water. The combined aqueous washes were extracted with three 50-mL portions of diethyl ether. The combined organic extracts were washed with 100 mL of 1 M aqueous sodium bisulfite, dried (MgSCXi) and concentrated in vacuo. The crude yellow oil was purified by column chromatography over 50 g of silica gel

(eluted with hexanes-dichloromethane 4:1) to afford 1.93 g (90%) of iodide 205 as a pale yellow oil: 1H NMR (CDCI 3, 200 MHz) 5 2.12 (m, 2 H, CH2), 3.32 (t, J= 6.1 Hz, 2H, CH2I), 3.55 (t,

J = 5.0 Hz, 2H, CH20), 4.52 (s, 2H, CH2Ph), 7.31-7.45 (m, 5H, ArH).

H,N' '•OTBDMS

210

3-(ferf-Butyldimethylsiloxy)-1-propylamine (210). To a solution of 5.63 g

(75.0 mmol) of 3-amino-1-propanol 179 in 300 mL of benzene chilled in a water bath at 10°C was added 24.8 mL (165 mmol) of diazabicyclo-[2.2.2]-undecene and 23.74 g (157.5 mmol) of fe/1-butyldimethyfsilyl chloride. The reaction mixture was heated at reflux for 1.5 h, allowed to cool to room temperature and filtered. The filtrate was concentrated in vacuo to afford 23.95 g of a yellow oil which was diluted with 135 mL of methanol. The solution was chilled in an ice bath and 2.1 g of acidic Dowex-50 resin was added. The mixture was stirred at 0°C for 15 min, filtered and was concentrated in vacuo. The crude oil was purified by distillation under reduced pressure to afford 11.96 g (92%) of amine 210 as a colorless oil: bp 64-66°C (3.5 mm); IR (neat)

3373 cm-1: 1H NMR (CDCI3, 200 MHz) 5 0.00 (s, 6H, Si(CH3)2), 0.84 (s, 9H, C(CH 3)3 ) .1 -45 (br

S, 2H, NH2), 1.60 (p, J= 6.4 Hz, 2H, CH2), 2.74 (t, J= 6.7 Hz, 2H, CH2N), 3.64 (t,J= 6.1 Hz, 2H,

CH20); 13C NMR (CDCI3, 62.9 MHz) 8 -5.4 (q), 18.2 (s), 25.9 (q), 36.4 (t), 39.4 (t), 61.2 (t); exact mass calcd. for CgH^NOSi m/e 189.1549, found m/e 189.1556. COOEt 129

r S TBDMSO^ y v ^N H HN^ ^ ^OTBDMS

211

N-[3-(ferf-Butyldimethylsiloxy)propyl]-2-[[3-(fe/1-butyldlmethylsiloxy)propylamlno]methyl]-p-alanine, ethyl ester (211). To a solution of 21.6 6 g (125 mmol) of amine 210 in 75 mL of chloroform chilled in an ice bath was added dropwise over 3 h a solution of 8.04 g (41.7 mmol) of ester 182 in 120 mL of chloroform. The mixture was allowed to warm up to room temperature over 1 h, heated at reflux for 19 h, cooled to room temperature and washed with 400 mL of 1 M aqueous sodium hydroxide. The aqueous wash was extracted with three 400-mL portions of ethyl acetate. The combined organic extracts were dried

(MgSCU) and concentrated in vacuo. The crude oil was purified by column chromatography over 250 g of silica gel (eluted with dichloromethane-methanol, 25:1) to afford 14.99 g (73%) of diamine 211 as a pale yellow oil: IR (neat) 3354,1732 cm-1; 1H NMR (CDCI 3 , 200 MHz) 5 0.02

(S, 12H, Si(CH3)2), 0.87 (s, 18H, C(CH 3)3), 1.24 (t, J= 7.1 Hz, 3H, CH3), 1.59-1.72 (m, 6 H, CH2 and NH), 2.62-2.90 (m, 9H, CH2N and CHCO), 3.64 (t ,J= 6.2 Hz, 4H, CH2OSi), 4.14 (q, J= 7.1

Hz, 2H, CH20); 13C NMR (CDCI3, 62.9 MHz) 8 -5.4 (q), 14.2 (q), 18.3 (s), 25.9 (q), 32.4 (t), 44.8

(d), 46.8 (t), 50.2 (t), 60.7 (t), 61.3 (t), 173.7 (s); exact mass calcd. for C 24Hs4N20 4 Si2 m/e

490.3622, found m/e 490.3623.

COOEt rS TBDMSOs. ^N> ^Nv JOTBDMS T O

212

Ethyl hexahydro-1,3-[3-(ferf*butyldlmethylsiloxy)propyf]-2-oxo-5-pyrimi« dinecarboxylate (212). A solution of 8.83 g (18.0 mmol) of diamine 211 and 4.37 g (27.0 130 mmol) of carbonyldiimidazole in 70 mL of benzene was heated at reflux for 17 h and concentrated in vacuo. The crude oil was purified by column chromatography over 90 g of silica gel (eluted with 1100 mL of ethyl acetate-hexanes, 1:4 then with 400 mL of ethyl acetate- hexanes, 1:3) to afford 5.35 g (58%) of urea 212 as a pale yellow oil: IR (neat) 1738,1644 cm'1;

1H NMR (CDCI3, 200 MHz) 8 0.03 (S, 12H, Si(CH3)2), 0.88 (s, 18H, C(CH3)3), 1.24 (t, J= 7.1 Hz,

3H, CH3), 1.75 (p, 6.8 Hz, 4H, CH2), 2.87-3.00 (m, 1H, CHCO), 3.25-3.57 (m, 8 H, CH2N),

3.63 (t,J= 6.3 Hz, 4H, CH2OSi), 4.17 (q, J = 7.1 Hz, 2 H, CH20); 13C NMR (CDCI3l 62.9 MHz) 8 -

5.4 (q), 14.1 (q), 18.3 (s), 25.9 (q), 31.1 (t), 38.4 (d), 45.5 (t), 47.4 (t), 60.9 (t), 61.2 (t), 155.3 (s),

173.7 (s); exact mass calcd. for C 25H52N2OsSi2 m/e 516.3415, found m/e 516.3419.

COOEt

1 95

Ethyl hexahydro-1, 3-(3-hydroxypropyl)-2-oxo-5-pyrimidinecarboxylate

(195). A solution of 5.74 g (11.1 mmol) of urea 212 and 0.80 g of strongly acidic Dowex resin in 170 mL of methanol was stirred at room temperature for 4.5 h, filtered and concentrated in vacuo. The crude oil was purified by column chromatography over silica gel (eluted with dichloromethane-methanol, 10:1), to yield 2.69 g (84%) of diol 195 as a pale yellow oil: IR (neat)

3386, 1733, 1614 cm'1; 1H NMR (CDCI 3 , 300 MHz) 8 1.24 (t, J= 7.1 Hz, 3H, CH3), 1.63-1.73

(m, 4H, CH2), 2.92-2.99 (m, 1H, CHCO), 3.34-3.54 (m, 12H, CH2N and CH 20), 3.87 (t,J= 7.0

Hz, 2H, OH), 4.19 (q, J= 7.1 Hz, 2H, CH2OCO); 13C NMR (CDCI3 , 75.5 MHz) 8 14.1 (q), 29.8 (t),

37.9 (d), 44.2 (t), 46.6 (t), 58.0 (t), 61.6 (t), 157.2 (s), 170.3 (s); exact mass calcd. for

C i3 H24N20 s m/e 288.1685, found m/e 288.1691. COOEt COOEt 131

MOMO .OMOM HO .OMOM

O o

213 214

Ethyl hexahydro-1,3-[3-(methoxymethoxy)propyl]-2-oxo-5-pyrimicline- carboxylate (213) and ethyl hexahydro-1-(3-hydroxypropyl)-3-[3-(methoxy-

methoxy)propyl]-2-oxo-5-pyrimldInecarboxylate (214). To a solution of 632 mg

(2.19 mmol) of diol 195 in 12.6 mL of dichloromethane chilled in an ice bath was added 0.95 mL

(5.48 mmol) of A/,/V-diisopropylethylamine and 392 pL (4.39 mmol) of methoxymethyl chloride.

The mixture was stirred at 0°C for 1.5 h, at room temperature for 30 min, diluted with 50 mL of dichloromethane and washed with 80 mL of water. The aqueous wash was extracted with three

70-mL portions of dichloromethane. The combined organic extracts were dried (MgS 0 4 ) and concentrated in vacuo. The residue was purified by column chromatography over silica gel

(eluted with dichloromethane-methanol, 30:1) to afford 266 mg (32%) of diprotected urea 213 as an oil: IR (neat) 1734,1640,1507 cm*1; 1H NMR (CDCI3, 200 MHz) 51.24 (t, J= 7.1 Hz, 3H,

CH3), 1.80 (p, J= 6.8 Hz, 4H, CH2), 2.88-2.96 (m, 1H, CHCO), 3.32 (s, 6H, OCH3), 3.23-3.70

(m, 12H, CH2N and CH 20), 4.15 (q, J= 7.1 Hz, 2H, CH2OCO), 4.57 (s, 4H, OCH20); 13C NMR

(CDCI3 , 62.9 MHz) 5 14.1 (q), 28.0 (t), 38.2 (d), 45.6 (t), 47.1 (t), 55.1 (q), 61.2 (t), 65.5 (t), 96.4

(t), 155.2 (s), 170.6 (s).

Further elution afforded 348 mg (48%) of alcohol 214 as an oil: IR (neat) 3388,1732,1615 cm"

1; 1H NMR (CDCI3, 250 MHz) 81.24 (t, J= 7.1 Hz, 3H, CH3), 1.63 (p, J= 5.7 Hz, 2H, CH2), 1.74-

1.85 (m, 2H, CH2); 2.87-2.97 (m, 1H, CHCO), 3.31 (s, 3H, OCH3), 3.26-3.63 (m, 12H, CH2N and

CH20), 4.15 (q, J = 7.1 Hz, 2H, CH2OCO), 4.41 (t, J= 7.1 Hz, 1H, OH), 4.56 (s, 2H, OCH20);

13C NMR (CDCI3, 62.9 MHz) 8 14.0 (q), 28.0 (t), 29.7 (t), 38.0 (d), 43.8 (t), 45.8 (t), 46.6 (t), 47.1

(t), 55.1 (q), 57.8 (t), 61.3 (t), 65.3 (t), 96.5 (t), 156.3 (s), 170.4 (s); exact mass calcd. for

C isH 28N206 m/e 332.1947, found m/e 332.1946. Further elution afforded 25 mg (12%) of starting material. COOEt COOEt 132

THPO ,OTHP

215 216

Ethyl hexahydro-1,3-[3-[(tetrahydro*2H-pyran-2*yl)oxy]propyl]-2>oxo-5- pyrlmldinecarboxylate (215) and ethyl hexahydro-1-(3-hydroxypropyl)-3-[3-

[(tetrahydro-2«-pyran-2-yl)oxy]propyl]-2-oxo-5-pyrlmldlnecarboxylate (216).

To a solution of 2.60 g (9.01 mmol) of diol 195 in 65 mL of dichloromethane was added 0.91 g

(1.02 mL, 10.8 mmol) of 3,4-dihydro-2H-pyran and 0.23 g (0.901 mmol) of pyridinium p- toluenesulfonate. The solution was stirred at room temperature for 22 h, diluted with 150 mL of dichloromethane and washed with 200 mL of half-saturated brine. The aqueous wash was extracted with two 150-mL portions of dichloromethane and 150 mL of ethyl acetate. The combined organic extracts were dried (MgS 0 4 ) and concentrated in vacuo. The residue was purified by column chromatography over silica gel (eluted with dichloromethane-methanol, 35:1) to yield 484 mg (35%) of diprotected urea 215 as an oil: IR (neat) 1735,1641 cm'1; 1H NMR

(CDCI3 , 300 MHz) 5 1.25 (t, J= 7.1 Hz, 3H, CH3), 1.44-1.62 (m, 8 H, CH2), 1.64-1.74 (m, 2H,

CH2), 1.74-1.86 (m, 6H, CH2), 2.88-2.97 (m, 1H, CHCO), 3.29-3.53 (m, 12H, CH2N and CH 20),

3.70-3.86 (m, 4H, CH 20), 4.15 (q, J= 7.1 Hz, 2H, CH2OCO), 4.53 (m, 2H, OCHO); 13C NMR

(CDCI3 , 62.9 MHz) 5 14.1 (q), 19.58 (t)*, 19.63 (t)\ 25.4 (t), 28.1 (t). 30.7 (t), 38.3 (d), 45.7 (t),

47.2 (t), 61.2 (t), 62.28 (t)*, 62.34 (t)*, 65.23 (t)*, 65.28 (t)*, 98.9 (d), 155.2 (s), 170.7 (s); exact mass calcd. for C2 iH 3sN 2 0 6 (M-OEt) m/e 411.2497, found m/e 411.2568 and for

C-|8 H3iN 20 5 (M+-OTHP) m/e 355.2234, found m/e 355.2299.

Further elution afforded 1.642 g (49%) of alcohol 216 as an oil: IR (neat) 3381,1735,1620 cm*

1; 1H NMR (CDCI3, 300 MHz) 8 1.25 (t, J= 7.1 Hz, 3H, CH3), 1.45-1.59 (m, 4H, CH2), 1.60-1.74

(m, 3H, CH2), 1.75-1.85 (m, 3H, CH2); 2.89-2.97 (m, 1H, CHCO), 3.31-3.64 (m, 12H, CH2N and

CH20), 3.70-3.86 (m, 2H, CH 20), 4.16 (q, J= 7.1 Hz, 2 H, CH2OCO), 4.39 (t, J= 6.9 Hz, 1H,

OH), 4.53 (m, 1H, OCHO); 13C NMR (CDCI3 , 62.9 MHz) 8 14.0 (q), 19.6 (t), 25.4 (t), 27.98 (t)*, 133 28.01 (t)*, 29.6 (t), 30.6 (t). 38.0 (d), 43.7 (t), 45.9 (t), 46.6 (t), 47.05 (t)*. 47.08 (t)*, 57.8 (t), 61.3

(t), 62.38 (t)*, 62.41 (t)*, 65.03 (t)\ 65.09 (t)*. 99.0 (d), 156.3 (s), 170.5 (s); exact mass calcd. for

C18 H32N2O5 (M+-OH) m/e 355.2234, found m/e 355.2251. Further elution afforded 195 mg

(8 %) of starting material.

COOEt

THPO.

2 1 8

1-[3-[A/-Carboxy-2*(trimethylsilyl)ethanesulfonamido]propyl]-3>[3*[(te' trahydro-2H-pyran-2-yl)oxy]propyl]hexahydro-2-oxo-5-pyrImldlnecarboxyllc acid, W-ferf-butyl ethyl ester (218). To a solution of 1.01 g (2.71 mmol) of alcohol 216 in

80 mL of tetrahydrofuran chilled in an ice bath was added successively 1.52 g (5.42 mmol) of sulfonamide 217, 2.13 g (8.12 mmol) of triphenylphosphine and 1.03 mL (6.50 mmol) of diethylazodicarboxylate dropwise over 5 min. The orange solution was stirred at 0°C for 5 min, at room temperature for 1 h and concentrated in vacuo. The semi-solid residue was purified by column chromatography over 50 g of silica gel (eluted with ethyl acetate-hexanes, 3:2 then 2:1) to yield 1.34 g of sulfonamide 218 as a pale yellow oil: IR (neat) 1728, 1640 cm*1; 1H NMR

(CDCI3 , 300 MHz) 6 0.02 (s, 9H, Si(CH3)3), 0.89-0.95 (m, 2H, CH 2Si), 1.24 (t, J = 7.1 Hz, 3H,

CH3), 1.48 (s, 9H, C(CH3)3), 1.39-1.53 (m, 4H, CH2), 1.62-1.73 (m, 1H, CH2), 1.75-1.91 (m, 5H,

CH2), 2.89-2.98 (m, 1H, CHCO), 3.25-3.53 (m, 12H, CH2N, CH20 and CH 2S02), 3.60-3.65 (m,

2H, CH2NS02), 3.69-3.84 (m, 2 H, CH20), 4.15 (q, J = 7.1 Hz, 2H, CH2OCO), 4.52 (m, 1H,

OCHO); 13c NMR (CDCI3, 62.9 MHz) 5 -2.1 (q), 10.3 (t), 14.1 (q), 19.58 (t)*, 19.62 (t)*, 25.4 (t),

27.9 (q), 28.1 (t), 28.6 (t), 30.7 (t), 38.2 (d), 44.9 (t), 45.3 (t), 45.8 (t), 46.7 (t), 47.2 (t), 50.7 (t),

61.2 (t), 62.26 (t)*, 62.32 (t)*, 65.19 (t)*, 65.24 (t)*, 84.1 (s), 98.9 (d), 151.6 (S), 155.3 (s), 170.6

(s); exact mass calcd. for C 2sHs3N3 0 9 SSi m/e 635.3274, found m/e 635.3247. COOEt 134

BOC I HO

2 1 9

1-[3-[N-Carboxy-2-(trimethylsilyl)ethanesulfonamldo]propyl]-3-(3-hydroxypropyl)hexahydro-2-oxo-5-pyrimldinecarboxylic acid, AMerf-butyl ethyl ester

(219). To a solution of 1.26 g (1.98 mmol), of tetrahydropyranyl ether 218 in 30 mL of methanol was added 125 mg of acidic Dowex-50 resin. The mixture was stirred at room temperature for 20 h, filtered and concentrated in vacuo. The residue was purified by column chromatography over 50 g of silica gel (eluted with 700 mL of ethyl acetate-hexanes, 5:2 then

600 mL of ethyl acetate-hexanes, 3:1) to yield 0.970 g (89%) of alcohol 219 as a pale yellow oil:

IR (neat) 3386,1728,1617 crrr1; 1H NMR (CDCI 3 , 300 MHz) 5 0.03 (s, 9H, Si(CH 3)3), 0.90-0.97

(m, 2H, CH2Si), 1.25 (t, J= 7.1 Hz, 3H, CH3), 1.49 (s, 9H, C(CH3)3), 1.60-1.68 (m, 2H, CH2),

1.83-1.93 (m, 2H, CH2), 2.92-3.00 (m, 1H, CHCO), 3.24-3.55 (m, 12H, CH 2N, CH20 and

CH2S02), 3.57-3.65 (m, 2H, CH2NS02), 4.16 (q, J= 7.1 Hz, 2H, CH2OCO), 4.34 (t, J= 6.6 Hz,

1H, OH); 13C NMR (CDCI3, 62.9 MHz) 5 -2.1 (q), 10.2 (t), 14.0 (q), 27.9 (q), 28.6 (t), 29.6 (t),

37.8 (d), 43.7 (t), 44.7 (t), 45.5 (t), 46.6 (t), 50.7 (t), 57.7 (t), 61.3 (t), 84.2 (s), 151.5 (s), 156.4

(s), 170.4 (s); one carbon was not observed: exact mass calcd. for C 23H45N3 0 8 SSi m/e

551.2699, found m/e 551.2713.

COOEt

H o

220

1»[3-[/V-Carboxy-2-(trfmethylsilyl)ethanesulfonamido]propyl]-3-(2-for- mylethyl)hexahydro-2-oxo-5-pyrimidlnecarboxylic acid, N-ferf-butyl ethyl ester 135 (220). To a solution of 747 mg (5.88 mmol) of oxallyl chloride in 15 mL of dichloromethane

stirred at -60°C was added 919 mg (11.8 mmol) of dimethylsulfoxide in 13 mL of

dichloromethane. The solution was stirred at -60°C for 20 min and a solution of 811 mg (1.47

mmol) of alcohol 219 in 30 mL of dichloromethane was slowly added. The mixture was stirred at

-60°C for 30 min and 1.49 g (14.7 mmol) of triethylamine was added. The mixture was allowed to warm up to room temperature, stirred for an additional 1 h and partitioned between 150 mL of water and 150 mL of dichloromethane. The aqueous layer was extracted with two 150-mL

portions of dichloromethane. The combined organic extracts were dried (MgS 0 4 ) and

concentrated in vacuo. The residue was purified by column chromatography over 20 g of silica

gel (eluted with ethyl acetate-hexanes, 2:1) to afford 676 mg (84%) of aldehyde 220 as a colorless oil: IR (neat) 1727, 1639 cm-1; 1H NMR (CDCI 3, 250 MHz) 5 0.03 (s, 9H, Si(CH3)3),

0.82-0.97 (m, 2H, CH 2Si), 1.25 (t, J= 7.1 Hz, 3H, CH3), 1.49 (s, 9H, C(CH3)3), 1.81-1.92 (m, 2H,

CH2), 2.66-2.72 (m, 2H, CH2CO), 2.89-2.98 (m, 1H, CHCO), 3.22-3.72 (m, 12H, CH2N and

CH2S 02), 4.16 (q, J= 7.1 Hz, 2H, CH2OCO), 9.77 (t, J= 1.5 Hz, 1H, COH); 13C NMR (CDCI3l

62.9 MHz) 6 -2.1 (q), 10.2 (t), 14.1 (q), 27.9 (q), 28.6 (t), 38.1 (d), 42.4 (t), 42.9 (t), 44.8 (t), 45.3

(t), 46.6 (t), 47.6 (t), 50.7 (t), 61.3 (t), 84.1 (s). 151.6 (s), 155.2 (s), 170.4 (s), 201.2 (d); exact

mass calcd. for C^H^NsO sSSi m/e 549.2542, found m/e 549.2560.

COOEt

222

1-[3-[/V-Carboxy-2-(trimethylsllyl)ethanesulfonamido]propyl]-3-(l-pro- penyl)hexahydro-2-oxo-5-pyrimidinecarboxyllc acid, N-tert-butyl ethyl ester

(222). To a solution of 348 mg (0.631 mmol) of alcohol 219 in 5 mL of tetrahydrofuran chilled in an ice bath was added 172 mg (0.757 mmol) of o-nitrophenol selenocyanate. A solution of 136 0.19 mL (0.757 mmol) of tri-n-butylphosphine in 1.3 mL of tetrahydrofuran was then added

dropwise over 5 min. The orange mixture was stirred at room temperature for 1 h, cooled to 0°C

and 358 mg (2.52 mmol) of disodium hydrogenphosphate was added, followed after 10 min by

0.98 mL (9.47 mmol) of 30% aqueous hydrogen peroxide. The mixture was stirred at room

temperature for 23 h, diluted with 70 mL of dichloromethane and washed with 50 mL of

saturated aqueous sodium bicarbonate. The aqueous wash was extracted with 50 mL of

dichloromethane and 50 mL of ethyl acetate. The combined organic extracts were dried

(MgSO/i) and concentrated in vacuo. The residual oil was purified by column chromatography

over 20 g of silica gel (eluted with ethyl acetate-hexanes, 1:2) to afford 176 mg (52%) of ally)

urea 222 as a pale orange oil: IR (neat) 1731,1643,1504 cm*1; 1H NMR (CDCI 3 , 300 MHz) 5

0.04 (s, 9H, Si(CH3)3), 0.90-0.97 (m, 2H, CH 2Si), 1.25 (t, J= 7.1 Hz, 3H, CH3), 1.50 (s, 9H,

C(CH3)3), 1.84-1.94 (m, 2H, CH2), 2.92-3.00 (m, 1H, CHCO), 3.28-3.53 (m, 8 H, CH2N and

CH2S 02), 3.62-3.67 (m, 2H, CH2NS02), 3.91-3.94 (m, 2H, CH 2C=C), 4.15 (q, J= 7.1 Hz, 2 H,

CH2OCO), 5.10-5.17 (m, 2H, =CH2), 5.68-5.79 (m, 1H, CH=); 13C NMR (CDCI3, 62.9 MHz) 5 -

2.1 (q), 10.3 (t), 14.1 (q), 27.9 (q), 28.6 (t), 38.1 (d), 44.9 (t), 45.4 (t), 46.3 (t), 46.7 (t), 50.4 (t),

50.7 (t), 61.2 (t), 84.1 (s), 116.7 (t). 133.9 (d), 151.6 (s), 155.2 (s), 170.5 (s); exact mass calcd.

for C23H43N30 7 SSi m/e 533.2593, found m/e 533.2592.

COOEt

23 9

1-[3-[N-Carboxy-2-(trimethylsilyl)ethanesulfonamldo]propyl]-3-[3-(l,3- d io xo la n - 2 -yl)ethyl]hexahydro- 2 -oxo- 5 -pyrlm!dinecarboxyllc acid, W-ferf-butyl ethyl ester (239). A solution of 288 mg (0.524 mmol) of aldehyde 220, 44 p.L (0.786 mmol) of ethylene glycol and 13 mg (0.524 mmol) of pyridinium p-toluenesulfonate in 25 mL of 137 benzene was placed in a Dean-Stark apparatus and heated at reflux for 22 h. The mixture was cooled to room temperature and washed with 20 mL of half-saturated brine. The aqueous wash was extracted with three 20-mL portions of dichloromethane. The combined organic extracts were dried (MgS 0 4 ) and concentrated in vacuo. The residue was purified by column chromatography over 10 g of silica gel (eluted with ethyl acetate-hexanes, 3:1) to yield 231 mg

(75%) of acetal 239 as a colorless oil: IR (neat) 1727,1639 cm’ 1; 1H NMR (CDCI 3 , 300 MHz) 5

0.06 (s, 9H, Si(CH 3)3), 0.88-0.99 (m, 2H, CH 2 Si), 1.27 (t, J= 7.1 Hz, 3H, CH3), 1.52 (s, 9H,

C(CH3)3), 1.85-1.94 (m, 4H, CH2), 2.93-3.01 (m, 1H, CHCO), 3.28-3.56 (m, 9H, CH2N and

CH2S02), 3.64-3.73 (m, 3H, CH2N), 3.80-3.89 (m, 2H, CH 2 0), 3.92-3.97 (m, 2H, CH 20), 4.17

(q, J= 7.1 Hz, 2H, CH2OCO), 4.97 (t, J= 4.8 Hz, 1H, OCHO); 13C NMR (CDCI3, 62.9 MHz) 5 -2.1

(q), 10.2 (t), 14.0 (q), 27.9 (q), 28.6 (t), 32.1 (t), 38.1 (d), 43.7 (t), 44.8 (t), 45.3 (t), 46.6 (t), 47.1

(t), 50.6 (t), 61.2 (t), 64.7 (t), 84.0 (s), 102.8 (d). 151.5 (s), 155.1 (s), 170.5 (s); exact mass calcd. for C25 H47N30 gSSi m/e 593.2804, found m/e 593.2829.

COOEt

2 4 0

Ethyl hexahydro-l,3-(3-acetoxypropyl)-2-oxo-5-pyriinfdinecarboxylate

(240). To a solution of 432 mg (1.50 mmol) of diol 195 in 15 mL of dichloromethane chilled in an ice bath was added successively 455 mg (0.63 mL, 4.50 mmol) of triethylamine, 383 mg

(0.35 mL, 3.75 mmol) of acetic anhydride and 18 mg (0.150 mmol) of 4-dimethylaminopyridine.

The mixture was stirred at 0°C for 10 min, at room temperature for 2 h, diluted with 50 mL of dichloromethane, washed successively with 25 mL of 10% aqueous hydrochloric acid, 25 mL of saturated aqueous sodium bicarbonate and 25 mL of brine, dried (MgSCU) and concentrated in vacuo. The residual oil was purified by column chromatography over 10 g of silica gel (eluted 138 with dichloromethane-methanoi, 20:1), to afford 536 mg (96%) of diacetate 240 as a colorless

Oil: IR (neat) 1735,1639,1508 cm-1; 1H NMR (CDCI 3 , 300 MHz) 51.26 (t, J= 7.1 Hz, 3H, CH3),

1.86 (p, J= 6.8 Hz, 4H, CH2), 2.03 (s, 6H, CH3CO), 2.90-2.98 (m, 1H, CHCO), 3.27-3.56 (m, 8 H,

CH2N), 4.07 (t,J= 6.4 Hz, 4H, CH20), 4.17 (q, J= 7.1 Hz, 2H, CH2OCO); 13C NMR (CDCI3, 62.9

MHz) 5 14.1 (q), 20.9 (q), 27.0 (t), 38.2 (d), 45.3 (t), 47.1 (t), 61.4 (t), 62.2 (t), 155.1 (s), 170.5

(s), 171.0 (s); exact mass calcd. forC-| 7H28N 2 0 7 m/e 372.1897, found m/e372.1893.

OTBDMS OTBDMS

CBZ COoEt CBZ

2 4 3

4,8-Dibenzyl 6 -ethyl 1,11-(ferf-butyldimethylslloxy)-4,8-diazaundecane

-4,6,8-tricarboxylate (243). To a solution of 4.91 g (10.0 mmol) of diamine 211 in 50 mL of tetrahydrofuran chilled in an ice bath was added 4.2 mL (30.0 mmol) of triethylamine and 3.6

mL (25.0 mmol) of benzyl chloroformate. The mixture was stirred at 0°C for 10 min, heated at

reflux for 9 h, cooled to room temperature, diluted with 250 mL of dichloromethane and washed with 200 mL of water. The aqueous wash was extracted with three 200-mL portions of dichloromethane. The combined organic extracts were dried (MgS 0 4 ) and concentrated in vacuo. The crude oil was purified by column chromatography over 100 g of silica gel (eluted with

ethyl acetate-hexanes, 1:8) to afford 5.92 g (78%) of ester 243 as a pale yellow oil: IR (neat)

1732, 1706 cm-1: 1H NMR (DMSO-d6 at 348K, 300 MHz) 5 0.01 (s, 12H, Si(CH3)2), 0.86 (s,

18H, Si(CH 3)3). 1.12 (t, J= 7.1 Hz, 3H, CH3), 1.66 (p, J= 6.8 Hz, 4H, CH2), 3.03-3.41 (m, 9H,

CHCO and CH 2N), 3.55 (t, J= 6.1 Hz, 4H, CH2OSi), 4.00 (q, 7.1 Hz, 2H, CH2OCO), 5.02 (d,

J = 12.7 Hz, 2H, CH2Ph), 5.08 (d, J= 12.7 Hz, 2H, CH2Ph), 7.26-7.33 (m, 10H, ArH); 13C NMR

(DMSO-d6 at 373K, 125.8 MHz) 5 -5.9 (q), 13.3 (q), 17.3 (s), 25.3 (q), 30.6 (t), 43.7 (d), 44.4 (t),

47.0 (t), 59.8 (t), 65.8 (t), 65.9 (t), 126.9 (d). 127.2 (d), 127.8 (d), 136.5 (s), 154.9 (s), 172.0 (s); 139 mass spectrum (FAB) m/e (relative intensity) molecular formula C4oH66N208Si2: 759.6 (M++1,

21.0), 637 (100).

OH OH

CBZ C02Et CBZ

2 4 2

4,8-Dibenzyl 6-ethyl 4,8-diaza-l,1 l-undecanediol-4,6,8-tricarboxylate

(242). To a solution of 14.07 g (18.6 mmol) of 243 in 36 mL of tetrahydrofuran stirred at 0°C was added 46.4 mL (46.4 mmol) of a 1.0 M solution of n-tetrabutylammonium fluoride in tetrahydrofuran. The mixture was stirred at 0°C for 10 min, at room temperature for 2.75 h, diluted with 150 mL of dichloromethane and washed with 150 mL of water. The aqueous wash was saturated with sodium chloride and extracted with three 150-mL portions of ethyl acetate.

The combined organic extracts were dried (MgS 0 4 ) and concentrated in vacuo. The residual oil was purified by column chromatography over 100 g of silica gel (eluted with ethyl acetate- hexanes, 4:1) to afford 7.38 g (75%) of diol 242 as a pale yellow viscous oil: IR (neat) 3446,

1698,1608 cm-1; 1H NMR (DMSO-d6 at 340K, 300 MHz) 51.13 (t, J= 7.1 Hz, 3H, CH3), 1.63 (p,

J= 6.7 Hz, 4H, CH2), 3.06-3.42 (m, 13H, CHCO, CH2N and CH20), 4.00 (q, J= 7.1 Hz, 2H,

CH2OCO), 5.04 (d, J = 12.7 Hz, 2H, CH2Ph), 5.09 (d, 12.7 Hz, 2H, CH2Ph), 7.27-7.35 (m,

10H, ArH); 13C NMR (DMSO-d6 at 373K, 125.8 MHz) 5 13.4 (q), 30.8 (t), 43.8 (d), 44.6 (t), 47.0

(t), 58.1 (t), 59.9 (t), 65.9 (t), 126.9 (d), 127.3 (d), 127.9 (d), 136.6 (s), 155.0 (s), 172.2 (s); mass spectrum (FAB) m/e (relative intensity) molecular formula C28H38N20 8 :531.4 (M++1,100). OTHP OTHP OHOH OTHP 140

CBZ COzEt CBZ CBZ COjEt CBZ

244 245

4,8-Dibenzyl 6-ethyl 4,8-dlaza-1,11 -[(tetrahydro-2H-py ran-2-y l)oxy]un- decane-4,6,8-trlcarboxylate (244) and 4,8-dibenzyl 6-ethyl 4,8-dlaza-n-[(tetrahydro-2H-pyran-2-yl)oxy]-1-undecanol-4,6,8-trlcarboxylate (245). To a solution of 997 mg (1.88 mmol) of diol 242 in 13 mL of dichloromethane was added 316 mg

(3.76 mmol) of 3.4-dihydro-2H-pyran and 71 mg (0.282 mmol) of pyridinium p-toluenesulfonate.

The mixture was stirred at room temperature for 3.5 h, diluted with 80 mL of dichloromethane and washed with 80 mL of water. The aqueous wash was extracted with 80 mL of dichloromethane and 80 mL of ethyl acetate. The combined organic extracts were dried

(MgS0 4 ) and concentrated in vacuo. The residue was purified by column chromatography over

60 g of silica gel (eluted with ethyl acetate-hexanes, 3:1) to afford 461 mg (35%) of ester 244 as a pale yellow oil: IR (neat) 1732,1704 cm'1; 1H NMR (DMSO-d6 at 343K, 250 MHz) 81.16 (t, J =

7.1 Hz, 3H, CH3), 1.43-1.55 (m, 8H, CH2), 1.57-1.67 (m, 2H, CH2), 1.70-1.80 (m, 6H, CH2),

3.05-3.48 (m, 13H, CHCO, CH2N and CH20), 3.57-3.66 (m, 2H, CH20), 3.71-3.80 (m, 2H,

CH20), 4.04 (q, J = 7.1 Hz, 2H, CH2OCO), 4.52 (m, 2H, OCHO), 5.06 (d, J = 12.7 Hz, 2H,

CH2Ph), 5.12 (d, J= 12.7 Hz, 2H, CH2Ph), 7.31-7.37 (m, 10H, ArH); 13C NMR (DMSO-d6 at

343K, 62.9 MHz) 8 13.3 (q), 18.7 (t), 24.6 (t), 27.7 (t), 29.9 (t), 43.7 (d), 44.6 (t), 48.8 (t), 59.8 (t),

61.0 (t), 63.9 (t), 65.9 (t), 97.7 (d), 126.9 (d), 127.2 (d), 127.8 (d), 136.4 (s), 154.9 (s), 172.0 (s); mass spectrum (FAB) m/e (relative intensity) molecular formula C38H54N20k>: 531.4 (M+-

Ci 2H io ,100).

Further elution afforded 552 mg (48%) of alcohol 245 as a pale yellow oil: IR (neat) 3476,1731,

1704 cm-1; 1H NMR (DMSO-d6 at 333K, 300 MHz) 8 1.12 (t, J= 7.1 Hz, 3H, CH3), 1.40-1.52 (m,

4H, CH2), 1.54-1.75 (m, 6H, CH2), 3.04-3.12 (m, 1H, CHCO), 3.17-3.43 (m, 12H, CH2N and

CH20), 3.53-3.62 (m, 1H, CH20), 3.68-3.75 (m, 1H, CH20), 3.99 (q, 7.1 Hz, 2H, CH2OCO), 141 4.28 (m, 1H, OH), 4.48 (m, 1H, OCHO), 5.03 (d, J= 12.7 Hz, 2H, CH2Ph), 5.08 (d, J= 12.7 Hz,

2H, CH2Ph), 7.31-7.37 (m, 10H, ArH); 13C NMR (DMSO-d6 at 343K, 62.9 MHz) 8 13.3 (q), 18.7

(t), 24.6 (t), 27.7 (t), 29.9 (t), 30.7 (t), 43.7 (d), 58.0 (t), 59.8 (t), 61.1 (t), 63.9 (t), 65.86 (t), 65.90

(t), 97.7 (d), 126.88 (d), 126.92 (d), 127.2 (d), 127.8 (d), 136.5 (s), 155.0 (s), 172.1 (s); mass

spectrum (FAB) m/e (relative intensity) molecular formula C33H4eN20g: 531.4 (M+-C 6H5, 100).

BOC. .SES N OTHP CO CBZ COjEt CBZ

2 4 6

10,14-Dibenzyl 6-ferf-butyl 12-ethyl 2,2-dimethyl-17-[(tetrahydro-2H-

pyran-2-y l)oxy]-5-thia-6,10,14-triaza-2-silaheptadecane-6,10,12,14-tetracar-

boxylate, 5,5-dioxide (246). To a solution of 537 mg (0.874 mmol) of alcohol 245 in 25

mL of tetrahydrofuran chilled in an ice bath was added successively 443 mg (1.57 mmol) of

BOCNHSES, 643 mg (2.45 mmol) of triphenylphosphine and 0.33 mL (6.50 mmol) of diethyl

azodicarboxylate dropwise over a 5-min period. The orange solution was stirred at room temperature for 1.5 h and concentrated in vacuo. The semi-solid residue was purified by column chromatography over 20 g of silica gel (eluted with ethyl acetate-hexanes, 2:1) to yield

750 mg (98%) of sulfonamide 246 as a viscous pale yellow oil: IR (neat) 1727,1703 cm-1; 1H

NMR (DMSO-d6 at 338K, 300 MHz) 6 0.04 (s, 9H, Si(CH3)3), 0.85-0.91 (m, 2H, CH2Si), 1.12 (t, J

= 7.1 Hz, 3H, CH3), 1.40-1.52 (m, 4H, CH2), 1.46 (s, 9H, C(CH3)3), 1.57-1.84 (m, 6H, CH2),

3.02-3.62 (m, 15H, CHCO and CH2N and CH20 and CH2S02), 3.69-3.75 (m, 1H, CH20), 3.99

(q, J= 7.1 Hz, 2H, CH2OCO), 4.49 (m, 1H, OCHO), 5.01-5.11 (m, 4H, CH2Ph), 7.26-7.37 (m,

10H, ArH); 13C NMR (DMSO-d6 at 343K, 125.8 MHz) 8 -2.6 (q), 9.5 (t) 13.3 (q), 18.7 (t), 24.6 (t),

27.1 (q), 27.7 (t), 28.1 (t), 29.9 (t), 43.7 (d), 43.7 (t), 44.6 (t), 44.7 (t), 46.7 (t), 46.8 (t), 50.0 (t),

59.9 (t), 61.1 (t), 63.9 (t), 65.95 (t), 66.01 (t), 83.3 (s), 97.7 (d), 127.0 (d), 127.3 (d), 127.9 (d), 142 136.4 (s), 136.5 (s), 150.8 (s), 154.9 (s), 172.1 (s); mass spectrum (FAB) m/e (relative intensity) molecular formula C43H67N30i2SSi: 876.5 (M+, 1.31), 650 (100).

BOC. -SES N OH

CBZ CO,Et CBZ

2 4 7

10,14-Dibenzyl 6-ferf-butyl 12-ethyl 2,2-dlmethyl-17-hydroxy-5-thia-6,

10,14-trlaza-2-silaheptadecane-6,10,12,14-tetracarboxylate, 5,5-dioxide

(247). To a solution of 1.29 g (1.47 mmol) of tetrahydropyranyl ether 246 in 20 mL of methanol was added 260 mg of strongly acidic Dowex resin. The mixture was stirred at room temperature for 18 h, filtered and concentrated in vacuo. The residue was purified by chromatography over 20 g of silica gel (eluted with ethyl acetate-hexanes, 1:1) to afford 0.933 g

(80%) of alcohol 247 as a viscous pale yellow oil: IR (neat) 3479,1732, 1698 cm-1; 1H NMR

(DMSO-d6 at 343K, 250 MHz) 5 0.08 (s, 9H, Si(CH3)3), 0.86-0.96 (m, 2H, CH2Si), 1.15 (t,J = 7.1

Hz, 3H, CH3), 1.46 (S, 9H, C(CH3)3), 1.65 (p, J= 6.8 Hz, 2H, CH2), 1.82 (m, 2H, CH2), 3.07-3.36

(m, 5H, CHCO and CH2N), 3.37-3.51 (m, 8H, CH2N, CH20 and CH2S 02), 3.56 (t, J= 7.4 Hz,

2H, CH2N S 02), 4.03 (q, J = 7.1 Hz, 2H, CH2OCO), 4.16 (m, 1H, OH), 5.03-5.14 (m, 4H,

CH2Ph), 7.31-7.37 (m, 10H. ArH); 13C NMR (DMSO-d6 at 343K, 125.8 MHz) 8 -2.6 (q), 9.5

(t),13.3 (q), 27.1 (q), 28.1 (t), 30.7 (t), 43.7 (d), 43.7 (t), 44.5 (t), 44.7 (t), 46.7 (t), 46.8 (t), 50.0

(t), 58.0 (t), 59.9 (t), 65.9 (t), 66.0 (t), 83.3 (S), 126.9 (d), 127.2 (d), 127.8 (d), 136.4 (s), 150.7

(s), 154.9 (s), 155.0 (s), 172.1 (s); mass spectrum (FAB) m/e (relative intensity) molecular formula C38H59N30nS S i: 794.5 (M++1, 6.3), 650 (100). 143

BOC^ ^SES N d HoA)

CBZ C02Et CBZ

2 4 8

10,14-Dibenzyl 6-fert-butyl 12-ethyl l6-carboxy-2,2-dimethyl-5-thia-6, l0,14-triaza-2-sllahexadecane-6,l 0,12,14-tetracarboxylate,5l5-dioxlde (248).

To a solution of 921 mg (1.16 mmol) of alcohol 247 in 8 mL of /V/,A/-dimethylformamide was added 1.529 g (4.06 mmol) of pyridinium dichromate. The mixture was stirred at room temperature for 18.5 h, poured into 60 mL of water and extracted with six 100-mL portions of diethyl ether. The combined organic extracts were dried (MgS 0 4 ) and concentrated in vacuo.

The residue was purified by column chromatography over 15 g of silica gel (eluted with dichloromethane-methanol, 15:1) to yeld 864 mg (92%) of carboxylic acid 248 as a viscous pale yellow oil: IR (neat) 3298,1730, 1713 cm'1: 1H NMR (DMSO-d6 at 363K, 250 MHz) 5 0.09 (s,

9H, Si(CH3)3), 0.92-0.99 (m, 2H, CH2Si), 1.17 (t, J= 7.1 Hz, 3H, CH3), 1.51 (s, 9H, C(CH3)3),

1.85 (m, 2H, CH2), 2.49 (m, 2H, CH2CO), 3.08-3.39 (m, 3H, CHCO and CH2N), 3.41-3.50 (m,

8H, CH2N and CH2S 02), 3.59 (m, 2H, CH2NS02), 4.05 (q, J= 7.1 Hz, 2H, CH2OCO), 5.11 (s,

4H, CH20), 7.32-7.86 (m, 10H, ArH); the acidic proton was not observed; 13C NMR (DMSO-d6 at 343K, 125.8 MHz) 8 -2.6 (q), 9.5 (t) 13.3 (q), 27.1 (q), 28.1 (t), 32.7 (t), 43.4 (t), 43.7 (d), 43.7

(t), 44.7 (t), 46.6 (t), 47.1 (t), 50.0 (t), 59.9 (t), 66.0 (t), 83.3 (S), 127.0 (d), 127.3 (d), 127.9 (d),

136.4 (s), 150.8 (s), 154.8 (s), 154.9 (s), 171.97 (s), 172.04 (s); mass spectrum (FAB) m/e

(relative intensity) molecular formula C38Hs7N30 i 2SSi: 808.5 (M++ 1,21.4), 664 (100). 144

BOCv x SES N

S^Vi CBZ COjEt CBZ

2 4 9

10,14-Dibenzyl 6-ferf-butyl 12-ethyl 16-methyl 2,2-dlmethyl-5-thia-6,

10,l4-triaza-2-sllahexadecane-6,10l12,14>16-pentacarboxylate, 5,5-dloxlde

(249). To a solution of 121 mg (0.150 mmol) of carboxylic acid in 1.5 mL of acetone was added

23 mg (0.165 mmol) of potassium carbonate and 14 pL (0.150 mmol) of dimethyl sulphate. The mixture was heated at reflux for 2.5 h, diluted with 20 mL of dichloromethane and washed with

15 mL of 10% aqueous citric acid. The aqueous wash was extracted with 15 mL of dichloromethane and 15 mL of ethyl acetate. The combined organic extracts were dried

(MgS0 4 ) and concentrated in vacuo. The residue was purified by column chromatography over

5 g of silica gel (eluted with ethyl acetate-hexanes, 1:3) to afford 77 mg (63%) of ester 249 as a pale yellow oil: IR (neat) 1698,1651 cm'1: 1H NMR (DMSO-d6 at 363K, 250 MHz) 8 0.08 (s, 9H,

Si(CH3)3), 0.91-0.96 (m, 2H, CH2Si), 1.15 (t, J= 7.1 Hz, 3H, CH3), 1.49 (s, 9H, C(CH3)3), 1.73

(m, 2H, CH2), 2.50 (m, 2H, CH2CO), 3.05-3.34 (m, 3H, CHCO and CH2N), 3.38-3.49 (m, 8H,

CH2N and CH2S 0 2), 3.54 (m, 2H, CH2NS02), 3.60 (s, 3H, CH30), 4.03 (q, J = 7.1 Hz, 2H,

CH2OCO), 5.09 (m, 4H, CH20), 7.29-7.71 (m, 10H, ArH); 13C NMR (DMSO-d6 at 343K, 125.8

MHz) 8 -2.5 (q), 9.5 (t) 13.3 (q), 27.1 (q), 28.1 (t), 28.5 (t), 43.3 (t), 43.7 (d), 43.7 (t), 44.7 (t), 46.6

(t), 47.0 (t), 50.0 (t), 50.8 (q), 59.9 (t), 66.0 (t), 66.1 (t), 83.3 (s), 127.3 (d), 127.4 (d), 127.9 (d),

136.4 (s), 150.7 (s), 154.8 (s), 172.0 (s); mass spectrum (FAB) m/e (relative intensity) molecular formula C39 H59N3O i2SSi: 822.5 (M++1, 0.81), 147 (100). BOC. „SES 145 N c1 ' i CBZ COjEt CBZ

251

10,14-Dibenzyl 6-ferf-butyl 12-ethyl 2,2-dimethyl-5-thla-6,10,14-triaza-

2-sila-16-heptadecene-6,10,12,l4-tetracarboxylate, 5,5-dioxide (251). To a solution of 455 mg (0.573 mmol) of alcohol 247 in 5 mL of tetrahydrofuran chilled in an ice bath was added 156 mg (0.686 mmol) of o-nitrophenol selenocyanate. A solution of 0.20 mL (0.803 mmol) of tri-n-butylphosphine in 1.4 mL of tetrahydrofuran was then added dropwise over 5 min.

The orange mixture was stirred at room temperature for 1 h, cooled to 0°C and 325 mg (2.47 mmol) of disodium hydrogenphosphate was added, followed after 10 min by 0.89 mL (8.60 mmol) of 30% aqueous hydrogen peroxide. The mixture was stirred at room temperature for 24 h, diluted with 60 mL of dichloromethane and washed with 40 mL of saturated aqueous sodium bicarbonate. The aqueous wash was extracted with 40 mL of dichloromethane and 40 mL of ethyl acetate. The combined organic extracts were dried (MgSC> 4) and concentrated in vacuo.

The residual oil was purified by column chromatography over 30 g of silica gel (eluted with 600 mL of ethyl acetate-hexanes, 1:5 then 500 mL of ethyl acetate-hexanes, 1:4) to afford 356 mg

(80%) of 251 as a pale orange oil: IR (neat) 1712,1586 cm'1; 1H NMR (DMSO-d6 at 343K, 300

MHz) 80.05 (S, 9H, Si(CH3)3), 0.86-0.92 (m, 2H, CH2Si), 1.12 (t, J= 7.1 Hz, 3H, CH3), 1.46 (s,

9H, C(CH3)3), 1.80 (p, J= 7.3 Hz, 2H, CH2), 3.01-3.42 (m, 7H, CHCO and CH2N), 3.42-3.47 (m,

2H, CH2S02), 3.52-3.57 (m, 2H, CH2NS02),3.73 (dd, J= 16.1,5.7 Hz, 1H, CH2C=), 3.87 (dd, J

= 16.1, 5.5 Hz, 1H, CH2C=), 3.99 (q, J= 7.1 Hz, 2H, CH2OCO), 5.01-5.11 (m, 6H, CH2Ph and

=CH2), 5.67-5.80 (m, 1H, CH=), 7.26-7.38 (m, 10H, ArH); 13C NMR (DMSO-d6 at 343K, 125.8

MHz) 8 -2.6 (q), 9.5 (t) 13.3 (q), 27.1 (q), 28.1 (t), 43.5 (d), 43.7 (t), 44.7 (t), 46.3 (t), 46.7 (t), 49.3

(t), 50.0 (t), 59.9 (t), 66.0 (t), 66.1 (t), 83.3 (s), 116.2 (t), 127.0 (d), 127.3 (d), 127.9 (d), 133.2

(d), 136.4 (s), 150.8 (s), 154.9 (s), 172.0 (s); mass spectrum (FAB) m/e (relative intensity) molecular formula C3 8 H57N3O i2SSi: 776.5 (M++1, 24.3), 632 (100). 146 COOEt

26 0

Ethyl [2-(dlbenzylamlno)methyl]acry!ate (260). To a solution of 0.386 g (2.0 mmol) of ethyl 2 -(bromomethyl)acrylate 182 in 3 mL of acetonitrile was added 0.332 g (2.4 mmol) of potassium carbonate and 0.395 g (2.2 mmol) of dibenzylamine in 1 mL of acetonitrile.

The mixture was stirred at room temperature for 10 min, at 65°C for 3 h, cooled and partitioned between 20 mL of water and 20 mL of dichloromethane. The aqueous layer was extracted with two 20-mL portions of dichloromethane. The combined organic extracts were dried (MgS 0 4 ) and concentrated in vacuo. The residue was purified by column chromatography over 10 g of silica gel (eluted with hexanes-ethyl acetate, 10:1) to afford 0.618 g (98%) of ester 260 as a pale yellow oil: IR (neat) 1715 cm'1; 1H NMR (CDCI 3, 250 MHz) 5 1.29 (t, J = 7.1 Hz, 3H, CH3),

3.33 (t, J= 1.3 Hz, 2H, CH2C=), 3.61 (s, 4H, CH2N), 4.20 (q, J= 7.1 Hz, 2H, CH20), 6.00 (d, J =

1.7 Hz, 1H, =CH2), 6.29 (d, J= 1.7 Hz, 1H, =CH2), 7.20-7.40 (m, 10H, ArH); 13C NMR (CDCI3 ,

62.9 MHz) 8 14.2 (q), 53.9 (t), 58.1 (t), 60.6 (t), 125.7 (t), 126.9 (d), 128.2 (d), 128.5 (d), 138.5

(s), 139.4 (s), 167.0 (s); exact mass calcd. for C 2qH23N0 2 m/e309.1729, found m/e 309.1702.

COOtBu Br

261

tert-Butyl p,P’-dibromoisobutyrate (261 ).86 A solution of 28.68 g (122 mmol) of carboxylic acid 185 in 30 mL of benzene placed in a heavy-walled bottle was cooled to -78°C and 100 mL of isobutylene was condensed. About 1.9 mL of concentrated sulfuric acid was added. The bottle was tightly closed, shaken at room temperature for three days, opened to the atmosphere and allowed to vent overnight. The contents were diluted with 100 mL of diethyl ether, washed with 80 mL of saturated aqueous sodium bicarbonate and 80 mL of brine, dried 147 (M gS 0 4 ) and concentrated in vacuo. The brownish solid residue was purified by recrystallization from boiling pentane to afford 23.53 g (74%) of ester 261 as a white solid: 1H

NMR (CDCI3, 300 MHz) 8 1.48 (s, 9H, C(CH3)3), 3.02-3.09 (m, 1H, CHCO), 3.64-3.76 (m, 4H,

CH2Br); 13C NMR (CDCI3, 62.9 MHz) 8 27.9 (q), 31.0 (t), 49.3 (d), 82.6 (s), 168.5 (s).

COOtBu

25 2

ferf-Butyl 2 -bromomethylacrylate (252).86 To a solution of 21.38 g (70.8 mmol) of ester 261 in 30 mL of benzene was added 14.8 mL (85.0 mmol) of N,N- diisopropylethylamine. The white suspension was heated at 45°C for 6 h, diluted with 200 mL of diethyl ether, washed successively with 140 mL of 10% aqueous hydrochloric acid, 140 mL of saturated aqueous sodium bicarbonate and 140 mL of brine, dried (MgS 0 4 ) and concentrated in vacuo. The brown crude oil was purified by distillation under reduced pressure to afford 12.81 g (82%) of ester 252 as a colorless oil: bp 62-64°C ( 1.8 mm) (lit.86 82-85°C (11 mm)); 1H NMR (CDCI3, 200 MHz) 51.50 (s, 9H, C(CH3)3), 4.13 (d, J= 0.9 Hz, 2H, CH 2Br), 5.84

(d, J= 0.9 Hz, 1H, =CH2), 6.21 (d, 0.9 Hz, 1H, =CH2); 13C NMR (CDCI3, 62.9 MHz) 5 28.0 (q),

29.7 (t), 81.6 (S), 127.9 (t), 138.9 (s), 163.5 (s).

Ph COOtBu

2 6 2

ferf-Butyl 2-[(dibenzylam ino)m ethyl]acrylate (262). To a solution of 13.15 g

(59.6 mmol) of acrylate 252 and 9.91 g (71.5 mmol) of potassium carbonate in 89 mL of acetonitrile was added dropwise over 15 min a solution of 11 .6 mL (65.6 mmol) of dibenzylamine 148 in 31 mL of acetonitrile. The mixture was heated at reflux for 3h and partitioned between 400 mL of water and 400 mL of dichloromethane. The aqueous layer was extracted with two 350-mL portions of dichloromethane. The combined organic extracts were dried (MgS 0 4 ) and concentrated in vacuo. The yellow solid residue was recrystallized from boiling hexanes to yield

16.37 g (82%) of ester 262 as a white solid: mp 52-54°C; IR (CHCI3) 1712 cm*1; 1H NMR

(CDCI3, 200 MHz) 81.48 (S, 9H, C(CH3)3), 3.28 (s, 2H, CH 2C=), 3.59 (S, 4H, CH 2N), 5.95 (d, J=

1.8 Hz, 1H, =CH2), 6.19 (d, J= 1.8 Hz, 1H, =CH2), 7.23-7.41 (m, 10H, ArH); 13C NMR (CDCI3,

62.9 MHz) 8 28.1 (q), 54.0 (t), 58.0 (t), 80.6 (s), 124.7 (t), 126.8 (d), 128.2 (d), 128.6 (d), 139.5

(s), 139.8 (s), 166.4 (s); exact mass calcd. for C 22H27N0 2 m/e337.2042, found m/e 337.2012.

COOtBu

HNv / sn^ ' 0TBDMS

2 6 3

A/,N-Dibenzyl-2-[[3-(terf-butyldimethylsiloxy)propylamino]methyl]-p>alanlne, ferf-butyl ester (263). To a solution of 10.56 g (55.9 mmol) of amine 210 in 250 mL of tetrahydrofuran stirred at -78°C was added 36.4 mL (58.3 mmol) of n-butyllithium (1 .6 M solution in hexanes). The mixture was stirred at -78°C for 40 min and a solution of 16.37 g (48.6 mmol) of ester 262 in 140 mL of tetrahydrofuran was added dropwise over a 25-min period.

The resulting solution was stirred at -78°C for 3.5 h, poured into 1000 mL of saturated aqueous ammonium chloride and extracted with two 450-mL portions of ethyl acetate. The combined organic extracts were dried (MgSC> 4) and concentrated in vacuo. The crude oil was purified by column chromatography over 300 g of silica gel (eluted with 1600 mL of ethyl acetate-hexanes,

1:3) to afford 17.85 g ( 66%) of amine 263 as a pale yellow oil: IR (neat) 3341, 1727 cnrr1; 1H

NMR (CDCI3l 300 MHz) 8 0.05 (s, 6H, Si(CH3)2), 0.90 (s, 9H, SiC(CH3)3), 1.45 (s, 9H, C(CH3)3),

1.63 (p, J = 6.6 Hz, 2H, CH2), 2.48-2.83 (m, 8 H, CHCO, CH2N and NH), 3.56 (s, 4H, CH 2Ph),

3.65 (t, J= 6.3 Hz, 2H, CH20), 7.20-7.35 (m, 10H, ArH); 13C NMR (CDCI3, 62.9 MHz) 8 -5.3 (q), 149 18.3 (S), 26.0 (q), 28.1 (q), 33.2 (t), 45.4 (d), 46.7 (t), 50.4 (t), 54.3 (t), 58.5 (t), 61.5 (t), 80.3 (s),

126.9 (d), 128.1 (d), 129.0 (d), 139.1 (s), 173.8 (s); exact mass calcd. for C 3 iHsoN 2 0 3 Si m/e

526.3593, found m/e 526.3546.

Ph > COOtBu

„___ JDTBDMS CBZ ^

2 6 4

6 -Benzyl 4-ferf-butyl 2-benzyl-9-(/erf-butyldimethylsiloxy)-2,6-diaza-1- phenylnonane-4,6-dicarboxylate (264). To a solution of 17.66 g (33.7 mmol) of amine

263 in 180 mL of tetrahydrofuran chilled in an ice bath was added 6 .6 mL (47.2 mmol) of triethylamine and 6.0 mL (40.5 mmol) of benzyl chloroformate. The mixture was stirred at 0°C for

10 min, heated at reflux for 1.75 h, diluted with 500 mL of dichloromethane and washed with

500 mL of water. The aqueous wash was extraced with three 300-mL portions of dichloromethane. The combined organic extracts were dried (MgSC> 4) and concentrated in vacuo. The crude oil was purified by column chromatography over 300 g of silica gel (eluted with

800 mL of ethyl acetate-hexanes, 1:15 then with 910 mL of ethyl acetate-hexanes, 1:12 then with 770 mL of ethyl acetate-hexanes, 1:10) to afford 18.54 g (84%) of benzyl carbamate 264 as a pale yellow oil: IR (neat) 1726,1704 cm'1: 1H NMR (DMSO-d 6 at 373K, 250 MHz) 5 0.04 (s,

6H, Si(CH3)2), 0.89 (s, 9H, SiC(CH3)3), 1.40 (s, 9H, C(CH3)3), 1.68 (p, J= 6.4 Hz, 2H, CH2),

2.43 (dd, 12.8, 5.5 Hz, 1H, CH 2N), 2.75 (dd, J= 12.8, 8.5 Hz, 1H, CH 2N), 2.92-3.43 (m, 1H,

CHCO), 3.01-3.43 (m, 4H, CH2NCO), 3.48-3.63 (m, 6H, NCH2Ph and C ^O S i), 5.05 (d, J =

12.7 Hz, 1H, OCH2Ph), 5.12 (d, J= 12.7 Hz, 1H, OCH2Ph), 7.21-7.39 (m, 15H, ArH); 13C NMR

(DMSO-d6 at 373K, 62.9 MHz) 8 -6.1 (q), 17.2 (s), 25.1 (q), 27.1 (q), 30.5 (t), 44.0 (d), 44.4 (t),

47.5 (t), 53.5 (t), 57.4 (t), 59.8 (t), 65.7 (t), 79.4 (s), 126.2 (d), 126.8 (d), 127.0 (d), 127.4 (d), 150 127.6 (d), 128.1 (d), 136.4 (s), 138.3 (s), 154.7 (s), 171.8 (s); exact mass calcd. for

C39H56N20sSi m/e 660.3961, found m/e 660.3960.

Ph COOtBu

2 6 5

6 -Benzyl 4-ferf-butyl 2-benzyl-2,6-dlaza-1-phenyl-9-nonanol-4,6- dicarboxylate (265). To a solution of 18.25 g (27.6 mmol) of silyl ether 264 in 100 mL of tetrahydrofuran chilled in an ice bath was added 41.5 mL (41.5 mmol) of a 1.0 M solution of n- tetrabutylammonium fluoride in tetrahydrofuran. The mixture was stirred at 0°C for 10 min, at room temperature for 2.25 h, diluted with 600 mL of dichloromethane and washed with 600 mL of water. The aqueous wash was extracted with three 200-mL portions of dichloromethane.

The combined organic extracts were dried (MgS 0 4 ) and concentrated in vacuo. The residual oil was purified by column chromatography over 150 g of silica gel (eluted with 1200 mL of ethyl acetate-hexanes, 1:2 then with 1000 mL of ethyl acetate-hexanes, 1:1) to afford 14.62 g (97%) of alcohol 265 as a clorless oil: IR (neat) 3464,1724,1702 cm’1; 1H NMR (DMSO-d 6 at 373K,

250 MHz) 5 1.41 (s, 9H, C(CH3)3), 1.65 (p, J= 7.0 Hz, 2H, CH2), 2.43 (dd, J= 12.8, 5.5 Hz, 1H,

CH2N), 2.75 (dd, J= 12.8, 8.5 Hz, 1H, CH 2N), 2.91-3.02 (m, 1H, CHCO), 3.10-3.45 (m, 6H,

CH2NCO and CH 20), 3.50 (d, J= 13.8 Hz, 2H, NCH 2Ph), 3.61 (d, J = 13.8 Hz, 2H, NCH 2Ph),

4.03 (t, J = 5.0 Hz, 1H, OH), 5.05 (d, J = 12.7 Hz, 1H, OCH2 Ph), 5.12 (d, J = 12.7 Hz, 1H,

OCH2 Ph), 7.20-7.36 (m, 15H, ArH); 13C NMR (DMSO-d 6 at 373K, 62.9 MHz) 5 27.2 (q), 30.6 (t),

44.1 (d), 44.5 (t), 47.4 (t), 53.5 (t), 57.4 (t), 58.0 (t), 65.7 (t), 79.4 (s), 126.2 (d), 126.8 (d), 127.0

(d), 127.4 (d), 127.6 (d), 128.1 (d), 136.5 (s), 138.3 (s), 154.8 (s), 171.9 (s); exact mass calcd. for C26H35N20 5 (M-C7H7) m/e 455.2548, found m/e 455.2542. 151

Ph Cr'N''A V *^CH3 I 3 H

2 6 7

Benzyl (methylsulfonyl)carbamate (267). To a solution of 1.90 g (20.0 mmol) of

methanesulfonamide in 47 mL of tetrahydrofuran stirred at -78°C was added 8.4 mL (21.0 mmol) of o-butyllithium (2.5 M solution in hexanes.) The resulting slurry was stirred at -78°C for 25 min

and 1.44 g (36.0 mmol) of 60% sodium hydride in mineral oil was added, followed by 5.4 mL

(36.0 mmol) of /V,W,N,A/-tetramethylethylenediamine. The mixture was allowed to warm up to

room temperature over 1.25 h and recooled to -78°C. Benzyl chloroformate (3.9 mL, 26.0

mmol) was added and the mixture was warmed up to room temperature and heated at 45°C for

18 h. The mixture was cooled in an ice bath, quenched by slow addition of 6 mL of fert-butanol

and 10 mL of water, and extracted with three 40-mL portions of water. The combined aqueous

extracts were acidified to pH 2 by addition of concentrated hydrochloric acid and extracted with three 100-mL portions of dichloromethane. The combined organic extracts were dried (MgSCU)

and concentrated in vacuo. The solid residue was recrystallized from ethyl acetate-hexanes to afford 2.91 g (64%) of carbamate 267 as a white solid: mp 110-112°C; IR (CHCI 3) 3384,1751 cm’1; 1H NMR (CDCI3, 200 MHz) S 3.25 (s, 3H, CH3), 5.21 (s, 2H, CH20), 7.37 (s, 5H, ArH); the

NH proton was not observed; 13C NMR (CDCI 3, 62.9 MHz) 5 41.2 (q), 68.9 (t), 128.5 (d), 128.7

(d), 128.9 (d), 134.3 (s), 151.0 (s); exact mass calcd. for C 9 H11NO4S m/e 229.0409, found m/e

229.0403. Anal, calcd. for C 9 H11NO4S: C, 47.15; H, 4.84. found C, 47.07; H, 4.85. 152 A 3 Ph' Ph IX•N' 'TMS I H I H TMS

268 269

Benzyl [[2-(trimethylsilyl)ethyl]sulfonyl]carbamate (269). Method A. To a solution of 2.32 g (22.9 mL of diisopropylamine in 20 mL of tetrahydrofuran stirred at -78°C was

added 9.2 mL (22.9 mmol) of n-butyllithium (2.5 M solution in hexanes.) The mixture was stirred

at -78°C for 30 min and a solution of 2.5 g (10.9 mmol) of benzyl(sulfonylmethyl)carbamate 267 was added dropwise over 20 min. The yellow solution was stirred at -78°C for an additional 10

min and transferred via a cannula over a 15-min period into a solution of 2.42 g (12.0 mmol) of

iodomethyl trimethylsilane stirred at -78°C. The mixture was stirred at -78°C for 1.75 h, allowed to warm up to room temperature over 1.75 h, poured into a mixture of 27 mL of 2 N aqueous

hydrochloric acid and 100 mL of ice, and extracted with four 60-mL portions of dichloromethane.

The combined organic extracts were washed successively with 40 mL of saturated aqueous sodium bisulfite and 40 mL of brine, dried (MgS 0 4 ) and concentrated in vacuo. The crude oil was purified by column chromatography over 40 g of silica gel (eluted with ethyl acetate-

hexanes, 1:10, then 1: 8 , then 1: 6 , then 1:4) to afford 0.72 g (19%) of carbamate 268 as a pale yellow oil: IR (neat) 3235,1748 cm-1; 1H NMR (CDCI3, 200 MHz) 5 0.06 (s, 18H, Si(CH3)3), 0.95

(dd, J= 15.2, 7.5 Hz, 2H, CH2Si), 1.24 (dd, J= 15.2, 6.1 Hz, 2H, CH2Si), 3.76 (m, 1H, CH), 5.20

(s, 2H, OCH2), 7.36 (s, 5H, ArH); the NH proton was not observed; 13C NMR (CDCI3, 75.5 MHz)

8 -0.9 (q), 19.4 (t), 57.8 (d), 68.6 (t), 128.4 (d), 128.6 (d), 128.7 (d), 134.5 (s), 150.9 (s); exact

mass calcd. for C i 7H3 iNC>4SSi2 m/e 401.1512, found m/e 401.1482.

Further elution afforded 1.50 g (44%) of carbamate 269 as a pale yellow oil: IR (neat) 3237,

1747 cm-1; 1H NMR (CDCI3, 200 MHz) 8 0.02 (s, 9H, Si(CH3)3), 0.98-1.04 (m, 2H, CH 2Si), 3.29-

3.35 (m, 2H, CH2S 02), 5.20 (s, 2H, OCH2), 7.36 (s, 5H, ArH); the NH proton was not observed;

13C NMR (CDCI3, 75.5 MHz) 8 -2.2 (q), 10.0 (t), 49.7 (t), 68.6 (t), 128.3 (d), 128.6 (d), 128.7 (d),

134.5 (s), 151.1 (s); exact mass calcd. fo rC i 3H2-|NC>4SSi m/e 315.0961, found m/e 315.0962. 153 Benzyl [[2-(trimethylsilyl)ethyl]suifonyl]carbamate (269). Method B. To a

solution of 8.16 g (45.0 mmol) of 2-[(trimethylsilyl)ethyl]sulfonamide 27088 in 61 mL of

tetrahydrofuran stirred at -78°C was added 35 mL (45.0 mmol) of methyllithium (1.6 M solution in

diethyl ether). The mixture was stirred at -78°C for 15 min, at 0°C for 25 min and 4.68 g (117

mmol) of 60% sodium hydride in mineral oil was added, followed by 6.7 mL (45.0 mmol) of

A/,A/,A/,A/-tetramethylethylenediamine. The mixture was then recooled to -78°C and 9.2 mL

(61.0 mmol) of benzyl chloroformate was added. The mixture was stirred at 0°C for 10 min, at

room temperature for 21 h, cooled in an ice bath and quenched by slow addition of 25 mL of

terf-butanol and enough water. The solution was acidified to pH 2 by addition of concentrated

hydrochloric acid and extracted with four 100-mL portions of dichloromethane. The combined

organic extracts were washed with 150 mL of brine, dried (MgS 0 4 ) and concentrated in vacuo.

The residue was purified by column chromatography over silica gel (eluted with ethyl acetate-

hexanes, 1 :6 then 1:4) to afford 12.34 g (87%) of carbamate 269 as a pale yellow oil.

Ph. COOtBu

Ph- . N . .X SES

CBZ XCBZ

271

6,10-Dlbenzyl 12-ferf-butyl l4-benzyl-2,2-dlmethyl-15-phenyl-5-thia-

6,10,14-triaza-2-silapentadecane-6,l 0,12-trlcarboxylate, 5,5-dioxide (271).

To a solution of 6.01 g (11.0 mmol) of alcohol 265 and 5.17 g (16.4 mmol) of 269 in 270 mL of tetrahydrofuran chilled in an ice bath was added 6.50 g (24.7 mmol) of triphenylphosphine and,

dropwise over a 5-min period, 3.2 mL (19.7 mmol) of diethylazodicarboxylate. The orange

solution was stirred at 0°C for 30 min, at room temperature for 3.5 h and concentrated in vacuo.

The semi-solid residue was purified by column chromatography over 250 g of silica gel (eluted with 1350 mL of ethyl acetate-hexanes, 1:8 then with 1200 mL of ethyl acetate-hexanes, 1:7 154 then with 700 mL of ethyl acetate-hexanes, 1: 6) to afford 8.69 g (94%) of sulfonamide 271 as a viscous pale yellow oil: IR (neat) 1731,1714 cm-1; 1H NMR (DMSO-d 6 at 373K, 250 MHz) 6 0.02

(s, 9H, Si(CH3)3), 0.89-0.96 (m, 2H, CH 2Si), 1.40 (s, 9H, C(CH3)3), 1.86 (p, J = 7.3 Hz, 2H,

CH2), 2.43 (dd, J= 12.8, 5.6 Hz, 1H, CH 2N), 2.75 (dd, J= 12.8, 8.4 Hz, 1H, CH 2N), 3.06-3.40

(m, 5H, CHCO and CH 2N), 3.42-3.49 (m, 2H, CH 2S 02), 3.51 (d, J = 13.8 Hz, 2H, NCH 2Ph),

3.61 (d, J = 13.8 Hz, 2H, NCH 2Ph), 3.62-3.68 (m, 2H, CH 2NS02), 5.03 (d, J= 12.6 Hz, 1H,

OCH2Ph), 5.12 (d, J= 12.6 Hz, 1H, OCH2Ph), 5.26 (s. 2H, OCH 2Ph), 7.20-7.41 (m, 20H, ArH);

13c NMR (DMSO-d6 at 373K, 125.8 MHz) 8 -2.6 (q), 9.3 (t), 27.2 (q), 28.0 (t), 43.9 (d), 44.1 (t),

44.6 (t), 47.1 (t), 50.1 (t), 53.4 (t), 57.4 (t), 65.9 (t), 68.0 (t). 79.6 (s), 126.4 (d), 126.9 (d), 127.2

(d), 127.4 (d), 127.6 (d), 127.8 (d), 127.9 (d), 128.0 (d). 128.3 (d), 134.8 (s), 136.4 (s), 138.4

(s), 152.0 (s), 154.8 (s), 172.0 (s); exact mass calcd. for C 46H61 N3OsSSi m/e 843.3951, found m/e 843.3978.

.COOtBu

-./XTn N J i 272

ferf-Butyl hexahydro-2-thioxo-l-[3-[2-(trimethylsilyl)ethanesulfonami- doJpropyl]-5-pyrim idlnecarboxylate (272). A solution of 4.012 g (4.75 mmol) of 271 in

55 mL of anhydrous ethanol was degassed with argon for 15 min and 1.54 g of palladium hydroxide on carbon was added. The mixture was hydrogenated in a Parr hydrogenator under a

60 psi hydrogen pressure for 16 h, and filtered through a fritted glass. The catalyst was washed several times with ethanol and the filtrate was concentrated in vacuo. 1H NMR analysis of the residue showed that cleavage of all four benzyl groups occured. To a solution of the residue in

40 mL of dichloromethane stirred at -78°C was added dropwise over 1.5 h a solution of 1.415 g

(7.13 mmol) of thiocarbonyldiimidazole in 35 mL of dichloromethane. The yellow solution was stirred at -78°C for 30 min, allowed to warm up to room temperature over 1 h and heated at reflux 155 for 17.5 h. The mixture was diluted with 250 mL of dichloromethane and washed with 100 mL of

water. The aqueous wash was extracted with two 100-mL portions of dichloromethane. The

combined organic extracts were dried (MgSC> 4) and concentrated in vacuo. The yellow semi

solid residue was purified by column chromatography over 35 g of silica gel (eluted with ethyl

acetate-hexanes, 1:1) to afford 1.065 g (51%) of thiourea 272 as a white solid: mp 116-117°C;

IR (CH2CI2) 1731,1548 cm-1; 1H NMR (CDCI 3, 300 MHz) 5 0.04 (s. 9H, Si(CH3)3), 1.02-1.08 (m,

2H, CH2Si), 1.49 (s, 9H, C(CH 3)3), 1.89 (p, J= 7.3 Hz, 2H, CH 2), 2.88-2.98 (m, 3H, CHCO and

CH2SO2), 3.12-3.18 (m, 2 H, CH2NSO2), 3.43-3.56 (m, 4H, CH2N), 3.91-4.00 (m, 1H, CH2N),

4.09-4.18 (m, 1H, CH 2N), 5.99 (brs, 1H, NH), 6.34 (brs, 1H, NH); 13C NMR (CDCI 3 , 62.9 MHz) 8

-2.0 (q), 10.5 (t), 27.9 (q), 28.0 (t), 37.6 (d), 39.5 (t), 42.5 (t), 47.0 (t), 49.0 (t), 50.8 (t), 82.6 (s),

169.0 (s), 177.9 (s); exact mass calcd. for C i 3H26N3 0 4 S2Si (M+-C4Hg) m/e 380.1136, found

m/e 380.1114 and for C i 3H26N3 0 3 S2Si (M + ^H gO ) m/e 364.1187, found m/e 364.1167.

, COOtBu

,so2 TMS

2 7 3

ferf-Butyl SAe.T.B.g-hexahydro-g-I^-ftrimethylsllylJethyllsulfonyl^H- p y rim id o [ 1 ,2 -a]pyrim ldine-3-carboxylate (273). To a solution of 1.053 g (2.41 mmol) of thiourea 272 in 15 mL of anhydrous methanol was added 185 pL (2.65 mmol) of iodomethane. The mixture was heated at 70°C for 1 h and concentrated in vacuo. To a solution of the residual foam in 40 mL of dichloromethane was added 4.4 mL (3.27 g, 25 mmol) of N,N- diisopropylethyl amine. The mixture was heated at reflux for 20 h, diluted with 300 mL of cold diethyl ether and washed with 150 mL of cold 1M aqueous sodium hydroxide. The organic layer was dried (Na 2SC>4) and concentrated in vacuo. The crude oil was purified by column chromatography over 30 g of activity grade II basic alumina (eluted with dichloromethane- 156 methanol, 200:1) to afford 0.790 g (81%) of guanidine 273 as a pale yellow oil: IR (neat) 1728,

1651,1644,1634 cm'1; 1H NMR (CDCI3, 500 MHz) 5 0.01 (s, 9H, Si(CH3)3), 0.89-0.96 (m, 2H,

CH2Si), 1.42 (s, 9H, C(CH3)3), 1.94-2.04 (m, 2H, CH2), 2.70-2.75 (m, 1H, CHCO), 3.11-3.25 (m,

3H, CH2SO2 and CH 2N), 3.33 (dd, J= 11.5, 8.7 Hz, 1H, CH2N), 3.45 (dd, J= 14.7, 8.6 Hz, 1H.

CH2N), 3.53-3.68 (m, 4H, CH 2N), 3.72-3.77 (m, 1H, CH2N); 13C NMR (CDCI3, 62.9 MHz) 8 -2.0

(q), 10.2 (t), 23.9 (t), 28.0 (q), 38.7 (d), 43.4 (t), 46.1 (t), 48.5 (t), 49.0 (t), 51.7 (t), 80.9 (s), 145.5

(s), 171.4 (s); mass spectrum (FAB) m/e (relative intensity) molecular formula C i 7H33N30 4 S2Si:

404.25 (M++1,100). Anal, calcd. for C i 7H33N3C>4S2Si: C, 46.65; H, 8.06. found C, 46.53; H,

8 .11.

,COOH

TMS

2 7 4

ferf-Butyl octahydro-9-[[2-(trimethylsilyl)ethyl]sulfonyl]-9aW-pyrimido

[1,2'a]-pyrimidin-3-carboxylate-9a-ylium chloride (274). A stream of gaseous hydrochloric acid was passed through a solution of 1.057 g (2.62 mmol) of ferf-butyl ester 273 in 46 mL of dichloromethane until saturation. The flask was then tightly closed and stored at 5°C for 24 h. The flask was opened and the mixture was allowed to warm up to room temperature over 1 h. At that point, a solid had precipitated and was collected on a Buchner funnel to afford

0.936 g (93%) of guanidine 274 as a white solid: mp; 1H NMR (D 2O, 300 MHz) S 0.00 (s, 9H,

Si(CH3)3), 0.92-0.98 (m, 2H, CH 2Si), 2.08 (m, 2H, CH2), 3.20 (m, 1H, CHCO), 3.44-3.59 (m, 4H,

CH2N and CH 2S02), 3.62 (dd, J = 8.1,5.1 Hz, 2H, CH 2N), 3.70 (d, J= 5.0 Hz), 2H, CH2 N); 13C

NMR (D20, 62.9 MHz) 5 -1.6 (q), 10.7 (t), 22.4 (t), 37.1 (d), 42.2 (t), 46.4 (t), 50.3 (t), 50.7 (t),

52.1 (t), 151.2 (s), 175.5 (s); mass spectrum (FAB) m/e (relative intensity) molecular formula 157 C i3H26CIN30 4 SSi: 348.2 (M+-HCI, 100). Anal, calcd for C 13H26CIN30 4 SSi: C, 40.66; H, 6.83. found C, 40.75; H, 6.78.

CBZ

TMS

CBZ

2 7 5

3l4,6l7l8>9-Hexahydro-9-[[2*(trlmethylsllyl)ethyl]sulfonyl]-2//-pyriml- do[l,2-a]pyrimidine-3-carboxylate, ester with [3-[/\f-[4-(carboxyamino)butyl]>

16-hydroxyhexadacanamldo]propyl]carbamic acid, dibenzyl ester (275). To a solution of 182 mg (0.474 mmol) of guanidinium chloride 274 and 316 mg (0.474 mmol) of alcohol 174 in 6 mL of A/,A/-dimethylformamide was added 114 mg (0.520 mmol) of dicyclohexylcarbodiimide and 77 mg (0.620 mmol) of 4-dimethylaminopyridine. The mixture was stirred at room temperature for 16 h, diluted with 150 mL of diethyl ether and washed with 50 mL of 1 M aqueous sodium hydroxide. The aqueous wash was extracted with two 80-mL portions of dichloromethane. The combined organic extracts were dried (MgS 0 4 ) and concentrated in vacuo. The residue was purified by column chromatography over 10 g of activity grade II basic alumina (eluted with dichloromethane-methanol, 300:1, then 250:1, then 200:1) to afford 305 mg (65%) of ester 275 as a pale yellow oil: IR (neat) 3343, 1725,1633, 1530 cm*1; 1H NMR

(CDCI3, 250 MHz) 6 0.06 (s, 9H, Si(CH3)3), 0.89-0.98 (m, 2H, CH 2Si), 1.17-1.35 (m, 18H, CH2),

1.42-1.68 (m, 10H, CH2), 1.70-1.82 (m, 2H, CH2), 1.91-2.03 (m, 4H, CH2), 2.22-2.26 (m, 2H,

CH2CO), 2.76-2.86 (m, 1H, CHCO), 3.06-3.28 (m, 8 H, CH2N and CH 2S 02), 3.30-3.58 (m, 5H,

CH2N), 3.60-3.,75 (m, 5H, CH2N), 4.08 (t, J= 7.0 Hz, 2H, CH2OCO), 4.96 (brs, 1H, NH), 5.02-

5.10 (m, 4H, PhCH2), 5.78 (br s, 1H, NH), 7.27-7.37 (m, 10H, ArH); 13C NMR (DMSO-d 6 at 158 373K, 125.8 MHz) 1.2 (q), 19.8 (t), 23.9 (t), 24.57 (t), 24.62 (t), 24.8 (t), 25.0 (t), 27.6 (t), 28.1 (t),

28.3 (t), 28.4 (t), 28.5 (t), 31.8 (t), 32.9 (i), 35.8 (d), 37.3 (t), 46.2 (t), 47.0 (t), 64.5 (t), 64.77 (t),

64.83 (t), 127.0 (d), 127.1 (d), 127.8 (d), 136.9 (s), 150.4 (s), 155.6 (s), 169.6 (s); mass spectrum (FAB) m/e (relative intensity) molecular formula C 52H84 N6 0 gSSi: 997.7 (M++1, 26.7),

554 (100).

COOH

2 7 6

3-Carboxyoctahydro-9aH-pyrimido[1,2-a]pyrimidin-9a-ylium chloride

(276). To a suspension of 500 mg (1.31 mmol) of 274 in 10 mL of A/,A/-dimethylformamide was added 2.6 mL (2.6 mmol) of a 1 M solution of n-tetrabutylammonium fluoride in tetrahydrofuran.

The resulting clear solution was heated at 80°C for 4 h. The precipitated solid was collected on a Buchner funnel, dissolved in 5 mL of 1 M aqueous hydrochloric acid and the resulting solution was concentrated in vacuo to afford, after drying, 285 mg (100%) of guanidinium chloride 276 as a white solid: mp 209-212.5°C; 1H NMR (D20 , 300 MHz) 51.89 (p, J= 5.9 Hz, 2H, CH2), 3.12

(p, 5.1 Hz, 1H, CHCO), 3.17 (dt, J= 5.8, 1.4 Hz, 2 H, CH2N), 3.24-2.32 (m, 2H, CH2N), 3.43

(d, J= 4.0 Hz, 2H, CH2N), 3.49 (m, 2H, CH 2N); 13C NMR (D20, 75.5 MHz) 5 20.2 (t), 36.4 (d),

38.0 (t), 39.4 (t), 46.9 (t), 47.4 (t), 150.8 (s), 174.6 (s); mass spectrum (FAB) m/e (relative intensity) molecular formula CsHi 4CIN3 0 2: 916 ((M+-HCI) 5+1, 3.8), 734 ((M+-HCI) 4+1,3.7), 550

((M+-HCI)3+1. 19.8), 367 ((M+-HCI) 2+1, 74.9), 184 ((M+-HCI)+1,100). I

2 7 7

3-Carboxyoctahydro>9aH-pyrimido[l,2-a]pyrimicnn-9a-ylium chloride, ester with [3-[W -[4-(carboxyamlno)butyl]-l6-hydroxyhexadacanamido]propyl]carbamic acid, dlbenzyl ester (277). To a solution of 125 mg (0.568 mmol) of guanidinium chloride 276 and 387 mg (0.568 mmol) of alcohol 174 in 3 mL of N,N- dimethylformamide was added 135 mg (0.682 mmol) of 3-[(dimethylamino)pro- pyljethylcarbodiimide hydrochloride and 14 mg (0.114 mmol) of 4-dimethylaminopyridine. The mixture was stirred at room temperature for 22 h and 193 mg (0.284 mmol) of alcohol 174 was added. After an additional 18 h of stirring, the mixture was diluted with 60 mL of dichloromethane and washed with 20 mL of 1M aqueous hydrochloric acid. The aqueous wash was extracted with 20 mL of dichloromethane. The combined organic extracts were washed with 40 mL of saturated aqueous sodium bicarbonate, dried (MgS 0 4 ) and concentrated in vacuo. The residue was purified by column chromatography over 2 g of silica gel (eluted with dichloromethane-methanol, 20:1, then 5:1) to afford 315 mg of recovered starting alcohol 174.

Further elution afforded 254 mg (55%) of ester 277 as a colorless oil: IR (neat) 3296, 1729,

1714, 1651 cm*1; 1H NMR (DMSO-d6 at 373K, 500 MHz) 5 1.25 (s, 22H, CH2), 1.37-1.42 (m,

2H, CH2), 1.49-1.55 (m, 4H, CH2), 1.57-1.64 (m, 4H, CH2), 1.84-1.96 (m, 2 H, CH2), 2.22 (t, J =

7.3 Hz, 2H, CH2CO), 2.97-3.09 (m, 5H, CH2N and CHCO), 3.14-3.57 (m, 12H, CH 2N), 4.10 (dt,

J = 6 .6 , 4.1 Hz, 2H, CH2OCO), 5.00 (d, J = 17.7 Hz, 2H, CH2 Ph), 5.04 (d, J = 17.7 Hz, 2H,

CH2Ph), 6.86 (br s, 2H, NH), 7.28-7.37 (m, 10H, ArH), 8.06 (br s, 1H, NH), 8.10 (br s, 1H, NH);

13C NMR (DMSO-d6 at 373K, 125.8 MHz) 5 19.8 (t), 24.5 (t), 24.8 (t), 26.4 (t), 27.6 (t), 28.0 (t),

28.26 (t), 28.31 (t), 28.36 (t), 28.42 (t), 31.8 (t), 35.8 (d), 37.1 (t), 37.9 (t), 38.66 (t), 38.73 (t), 160 39.8 (t), 46.1 (t), 46.8 (t), 46.9 (t), 64.4 (t), 64.7 (t), 64.8 (t), 127.0 (d), 127.1 (d), 127.7 (d),

136.89 (s), 136.94 (s), 150.6 (s), 155.6 (s), 169.5 (s), 171.3 (s); mass spectrum (FAB) m/e

(relative intensity) molecular formula C 47H73N6O7CI: 834.8 ((M+-HCI) +1,100).

1 4

3-Carboxyoctahydro-9aW-pyrimido[1,2-a]pyrimidin-9a-yllum chloride,

ester with [3-[/V-(4-ammoniumbutyl)-16-hydroxyhexadacanamido]propyl]ammo-

nium dichloride (277). To a solution of 68 mg (0.082 mmol) of 277 in 1.7 mL of ethanol was added 0.16 mL (1.63 mmol) of 1,4-cyclohexadiene and 68 mg of palladium on carbon. The

mixture was heated at 60°C for 3 h, filtered through a glass frit and 0.5 mL of a 0.8 M solution of

hydrochloric acid in methanol was added. The solution was concentrated in vacuo to afford 37

mg (70%) of 14 as a pale yellow oil: IR (neat) 3288, 1732, 1648, 1644, 1633 cm-1; 1H NMR

(DMSO-d6 at 373K, 500 MHz) 8 1.22-1.29 (m, 22H, CH2), 1.50-1.60 (m, 8 H, CH2), 1.81-1.95

(m, 4H, CH2), 2.28 (t, J= 7.2 Hz, 2H, CH2CO), 2.80-2.90 (m, 5H, CH2N and CHCO), 3.21-3.58

(m, 12H, CH2 N), 4.04-4.13 (m, 2H, CH2OCO), 8.15-8.20 (m, 8 H, NH); 13C NMR (DMSO-d6 at

373K, 125.8 MHz) 8 19.8 (t), 23.9 (t), 24.5 (t), 24.8 (t), 27.6 (t), 28.1 (t), 28.3 (t), 28.4 (t), 28.5 (t),

31.8 (t), 35.8 (d), 37.1 (t), 38.1 (t), 38.7 (t), 46.1 (t), 46.9 (t), 64.4 (t), 150.6 (S), 169.6 (s); mass

spectrum (FAB) m/e (relative intensity) molecular formula C 31H63N6O3CI3: 565.6 ((M+-3HCI)

+1,20), 149 (100). 161

EtO,CH.> C X

2 8 3

(S)-(+)-5-Carbethoxy-2-pyrrolidinone (283).93 To a suspension of 30.0 g

(0.232 mol) of L-pyroglutamic acid (282) in 275 mL of absolute ethanol cooled in an ice bath was added 25 mL (0.343 m o l) of thionyl chloride. The reaction mixture was stirred at room temperature for 3.5 h, neutralized by addition of an ethanolic solution of potassium hydroxide, filtered, and concentrated in vacuo. The residual oil was distilled under reduced pressure to yield 30.45 g (84%) of ester 283 as a colorless oil which solidified on standing: bp 138-143 °C

(1.4 mm) (lit.93 159-162°C (2 mm)); mp 47-49°C (lit .93 48-50°C); [a]D +5.6° (ethanol); IR

(CHCI3) 1774,1710 cm'1; 1H NMR (CDCI3 , 200 MHz) 5 1.28 (t, J= 7.1 Hz, 3H, CH3), 2.14-2.57

(m, 4H, CH2CH2), 4.11-4.31 (m, 3H, OCH2 and NCH), 6.41 ( br s, 1H, NH).

V EtOjC N OMe

2 8 4

(S)-(-)-/V-(Methoxymethyl)-5-carbethoxy-2-pyrrolidinone (284). To a solution of 5.0 g (31.8 mmol) of lactam 283 in 75 mL of dichloromethane was added 12.33 g

(95.4 mmol) of A/,/V/-diisopropylethylamine. The resulting solution was cooled in an ice bath and

6.43 g (79.5 mmol) of methoxymethyl chloride was added. The mixture was stirred at room temperature for 14 h, diluted with 400 mL of dichloromethane, washed successively with 200 mL of 10 % hydrochloric acid, 200 mL of saturated aqueous sodium bicarbonate, 200 mL of brine, dried (MgSCU) and concentrated in vacuo. The residual oil was chromatographed over

100 g of silica gel (eluted with acetone-hexanes, 1:3) to afford 5.43 g (85%) of lactam 284 as a pale yellow oil: [a]D-19.09° (CHCI 3); IR (neat) 1715,1680 cm1; 1H NMR (CDCI 3 , 200 MHz) S 162 1.25 (t, J= 7.1 Hz, 3H, CH3), 1.99-2.63 (m, 4H, CH 2CH2), 3.23 (S, 3H, OCH3), 4.07-4.27 (m, 3H,

NCH and OCH2), 4.53 (d, J= 10.2 Hz, 1H, NCH 20), 4.84 (d, J= 10.2 Hz, 1H, NCH 20); 13C NMR

(CDCI3 , 62.9 MHz) S 13.99 (q), 22.88 (t), 29.56 (t), 56.22 (q), 58.09 (d), 61.43 (t), 73.32 (t),

171.80 (s), 175.91 (s); exact mass calcd. for C 9 H15NO4 m/e 201.1001, found m/e 201.1007.

Etozc

2 8 5

(S)-(+)-5-Carbethoxypyrrolldlne-2-thione (285). To a solution of 15.0 g (95.4 mmol) of lactam 283 in 95 mL of dry dichloromethane was added 18.5 g (51.1 mmol) of

Lawesson’s reagent .136 The resulting mixture was stirred at room temperature for 3 h, filtered, and concentrated in vacuo. The residual oil was purified by chromatography over 400 g of silica gel (eluted with acetone-hexanes, 1:3) to afford 16.0 g (98%) of 285 as a white solid: mp 41-

43°C; [a]D +7.76° (CHCI3); IR (neat) 3180,1740,1508 c n r1; 1H NMR (CDCI3,250 MHz) 8 1.24

(t, 7.1 Hz, 3H, CH3), 2.18-2.32 (m, 1H, H4), 2.41-2.56 (m, 1H, H 4), 2.77-2.99 (m, 2H,

CH2CS), 4.12-4.25 (q, J= 7.1 Hz, 2H, COCH2), 4.45-4.51 (dd, J = 8.7, 6.0 Hz, 1H, NCH), 7.35

(brs, 1H, NH); 13C NMR (CDCI 3 , 62.9 MHz) 8 13.9 (q), 26.8 (t), 42.5 (t), 61.8 (t), 62.5 (d), 170.1

(S), 206.3 (s).

EtOjC' N

OMe

2 8 6

($)-(+)-A/-(Methoxymethyl)-5-carbethoxypyrrolidine-2-thione (286). A solution of 16.5 g (95.4 mmol) of thiolactam 285 in 231 mL of dry dichloromethane was cooled 163 in an ice bath. A/,A/-diisopropylethylamine (30.8 g, 0.238 mol) was added, followed by 15.35 g

(0.191 mol) of methoxymethyl chloride. The mixture was stirred at room temperature for 20 h, diluted with 1600 mL of dichloromethane, washed successively with 400 mL of 10% hydrochloric acid, 400 mL of saturated aqueous sodium bicarbonate, 400 mL of brine, dried

(MgS0 4 ), and concentrated in vacuo. The residual oil was chromatographed over 300 g of silica gel (eluted with acetone-hexanes, 1:5) to afford 16.4 g (79%) of 286 as a pale yellow oil: [

+55.8°(CHCI3): IR (neat) 1741 crrr1; 1H NMR (CDCI3, 200 MHz) 51.26 (t, J= 7.1 Hz, 3H, CH3),

2.09-2.26 (m, 1H, H4), 2.31-2.47 (m, 1H, H4), 3.04-3.13 (m, 2H, CH2CS), 3.32 (s, 3H, OCH3),

4.14-4.25 (q, J= 7.1 Hz, 2H, OCH2), 4.52-4.59 (dd, J = 11.3, 3.2 Hz, 1H, NCH), 4.90 (d, J =

10.3 Hz, 1H, NCH20), 5.44 (d, J= 10.4 Hz, 1H, NCH20); 13C NMR (CDCI3, 62.9 MHz) 8 13.99

(q), 25.03 (t), 44.10 (t), 57.39 (q), 61.77 (t), 64.46 (d), 77,19 (t), 170.23 (s), 206.32 (s); exact mass calcd. for C9 H15NO3S m/e 217.0774, found m/e 217.0771.

^O M e

2 8 7

(S)-(-)-W-(Methoxymethyl)-5-(hydroxymethyI)pyrrolidine-2-thione (287).

To a solution of 16.0 g (73.7 mmol) of thiolactam 286 in 192 mL of dry methanol cooled in an ice bath was added 4.18 g (0.111 mol) of sodium borohydride in three portions over 30 min. The mixture was stirred at room temperature for 10 h and quenched by addition of 190 mL of water.

The methanol was partially removed in vacuo and the remaining aqueous phase was saturated with sodium chloride and extracted with five 200-mL portions of dichloromethane. The combined organic extracts were dried (MgS04) and concentrated in vacuo. The residual crude oil was purified by chromatography over 200 g of silica gel (eluted with acetone-hexanes, 3:1) to afford 9.55 g (74%) of a 287 as colorless oil: [a]o -8.34° (CHCI 3); IR (neat) 3416 cm-1; 1H NMR

(CDCI3, 250 MHz) 81.82-1.95 (m, 1H, H4), 2.05-2.20 (m, 1H, H4), 2.87-3.17 (m, 3H, CH2CS and 164 OH), 3.41 (s, 3H, OCH3), 3.56-3.63 ( dd,J = 12.2 ,5.1 Hz, 1H, CH2OH), 3.76-3.82 (dd, J= 12.3,

2.7 Hz, 1H, CH2OH), 3.97-4.06 (m, 1H, CHN), 4.92 (d, J= 10.0 Hz, 1H, NCH20), 5.38 (d, J =

10.0 Hz, 1H, NCH20); 13C NMR (CDCI3, 62.9 MHz) 5 22.58 (t), 44.24 (t), 57.43 (t), 63.26 (t),

67.75 (t), 76.47 (t), 207.15 (s); exact mass calcd. for C 7H i3 N0 2S m/e 175.0668, found m/e

175.0662.

MsO,

OMe

2 8 8

(S)-(+)-W-(Methoxymethyl)-5-(methylsulfonyloxymethyl)pyrrolidine-2- thlone (288). To a solution of 545 mg (3.11 mmol) of alcohol 287 and 473 mg (4.67 mmol) of triethylamine in 19 mL of dichloromethane stirred at 0°C was added 463 mg (4.04 mmol) of methanesulfonyl chloride and 38 mg (0.31 mmol) of 4-dimethylaminopyridine. The mixture was stirred at room temperature for 18 h and partitioned between 40 mL of water and 40 mL of dichloromethane. The organic layer was washed successively with 30 mL of 10 % aqueous hydrochloric acid, 30 mL of saturated aqueous sodium bicarbonate and 30 mL of brine, dried

(MgS0 4 ) and concentrated in vacuo. The residue was purified by column chromatography over

15 g of silica gel (eluted with hexanes-acetone, 2:1) to afford 601 mg (76%) of mesylate 288 as an oil: [a]D+2.93° (CHCI3); IR (CHCI3) 2960 cm '1; 1H NMR (CDCI3, 250 MHz) 8 2.00-2.13 (m,

1H, H4), 2.21-2.37 (m, 1H, H4), 3.04 (s, 3H, SCH3), 3.01-3.30 (m, 2H, CH2CS), 3.40 (s, 3H,

0 CH3), 4.25-4.36 (m, 2H, CHN and CH 2OMs), 4.47 (dd, J = 10.6, 3.8 Hz, 1H, CH 2OMs), 5.15

(d, J= 10.3 Hz, 1H, NCH20), 5.31 (d, J= 10.3 Hz, 1H, NCH20); 13C NMR (CDCI3, 62.9 MHz) 8

23.1 (t), 37.7 (q), 44.1 (t), 57.4 (q), 63.1 (d), 67.9 (t), 76.6 (t), 206.8 (s); exact mass calcd. for

C8Hi 5 N 0 4S2 m/e 253.0443, found m/e 253.0453. 165 TsO^>CnX s

^"O M e

2 8 9

(S)-(+)-W-(Methoxymethyl)-5-(p-toluenesulfonyloxymethyl)pyrrolidine-2- thlone (289). To a solution of 678 mg (3.88 mmol) of alcohol 287 and 588 mg (5.81 mmol) of triethylamine in 23 mL of dichloromethane cooled to 0°C was added 962 mg (5.04 mmol) of p- toluenesulfonyl chloride and 50 mg (0.39 mmol) of 4-dimethylaminopyridine. The mixture was stirred at room temperature for 18 hours and partitioned between 50 mL of water and 50 mL of dichloromethane. The organic layer was washed successively with 35 mL of 10% hydrochloric acid, 35 mL of saturated aqueous sodium bicarbonate and 35 mL of brine, dried (MgS 0 4 ) and concentrated in vacuo. The residue was purified by column chromatography over 25 g of silica gel (eluted with hexanes-acetone, 3:1) to afford 1.126 g ( 8 8 %) of tosylate 289 as an oil:

[a]D+40.8° (CHCI3); IR (CHCI 3) 1598,1448,1421 cnrr1; 1H NMR (CDCI 3 , 250 MHz) 5 1.89-2.08

(m, 1H, H4), 2.12-2.27 (m, 1H, H4), 2.44 (s, 3H, ArCHg), 2.89-3.14 (m, 2H, CH 2CS), 3.27 (s, 3H,

OCH3), 4.11-4.26 (m, 3H, CHCH2OTs), 4.79 (dd, J= 10.4, 0.6 Hz, 1H, NCH20), 5.25 (d, J =

10.4 Hz, 1H, NCH20), 7.35 (d, J = 8.5 Hz, 2H, ArH meta), 7.75 (d, J= 8.4 Hz, 2H, ArH ortho);

13C NMR (CDCI3, 62.9 MHz) 5 21.6 (q), 23.0 (t), 44.0 (t), 57.2 (q), 62.6 (d), 68.3 (t), 76.2 (t),

127.9 (d), 130.0 (d), 132.3 (s), 145.4 (s), 206.7(d); exact mass calcd. for C i 4HigN 0 4S2 m/e

329.0757, found m/e 329.0729.

t b d m s o ^ , . N s

^O M e

2 9 7

(S)-(+)-A/-(Methoxymethyl)-5-(ferf-butyldimethylslloxymethyl)pyrrolIdl- ne- 2-thione (297). To a solution of 8.5 g (48.6 mmol) of alcohol 287 in 81 mL of N,N- 166 dimethylformamide was added 8.26 g (0.121 mol) of imidazole. The reaction mixture was heated at 35°C and 10.98 g (72.8 mmol) of tert-butyldimethylsilyl chloride was added. The resulting mixture was stirred at 35°C for 10 h, cooled, and diluted with 850 mL of dichloromethane. This organic layer was washed successively with 250 mL of 10% hydrochloric acid, 250 mL of saturated aqueous sodium bicarbonate and 250 mL of brine, dried (MgS04) and concentrated in vacuo. The residual oil was purified by chromatography over 300 g of silica gel (eluted with acetone-hexanes, 1:4) to afford 14.0 g (99.7%) of 297 as a pale yellow oil: [o]q

+31.9° (CHCI3); IR (neat) 1473, 1450 cm'1; 1H NMR (COCI 3, 250 MHz) S 0.02 (s, 3H, SiCH3),

0.03 (s, 3H, SiCH3), 0.85 (s, 9H, SiC(CH3)3), 1.91-2.21 (m, 2H, H4), 2.90-3.10 (m, 2H, CH2CS),

3.36 (S, 3H, OCH3), 3.64-3.69 (dd, J= 10.9, 3.5 Hz, 1H, CH 2OSi), 3.82-3.88 (dd, J= 10.8, 3.8

Hz, 1H, CH2OSi), 4.04-4.12 (m, 1H, NCH), 4.88-4.93 (dd, J = 10.2,1.0 Hz, 1H, NCH 20), 5.47-

5.51 (d, J= 10.2 Hz, 1H, NCH20); 13C NMR (CDCI3 , 75.5 MHz) 5-5.7 (q), -5.6 (q), 18.0 (s), 23.3

(t), 25.7 (q), 44.7 (t), 57.1 (q), 63.0 (t), 65.4 (d), 76.2 (t), 206.4 (s); exact mass calcd. for

C i3 H27N0 2SSi m/e 289.1533, found m/e 289.1534.

TBDMSO^^+^sMe

^O M e

2 9 8

(SH+)'N-(Methoxymethyl)-2-methylmercapto-5-(ferf-butyldimethylsilo- x y m e th y l)-A 1-pyrrolinlum iodide (298). To a solution of 16.68 g (57.7 mmol) of thiolactam 297 in 23 mL of diethyl ether was added 10.89 g of methyl iodide. The mixture was stirred at room temperature in the dark for 16 h. The precipitated yellow solid was filtered, washed with anhydrous ether and dried in vacuo to afford 18.43 g (74%) of salt 298 as a white solid: mp 90-92°C; [ct]D +7.90° (CHCI 3); IR (CHCI3) 1574, 2952 cm'1; 1H NMR (CDCI 3 , 300

MHz) 5 0.01 (s, 3H, CH3Si), 0.03 (s, 3H, CH3Si), 0.81 (s, 9H, (CH 3)3CSi), 2.03-2.15 (m, 1H, H4),

2.70-2.83 (m, 1H, H 4), 2.91 (s, 3H, SCH 3), 3.24-3.28 (m, 1H, H 3), 3.51 (s, 3H, OCH3), 3.75 (dd, 167 J= 11.6, 3.2 Hz, 1H, CH2OSi), 3.89-4.03 (m, 2H, H 3 and CH 2OSi), 4.80 (m, 1H, CHN), 5.09 (s,

2H, NCH20); 13C NMR (CDCI3, 62.9 MHz) 8 -5.7 (q), 17.6 (q), 17.8

59.1 (q), 63.3 (t), 73.0 (d), 80.2 (t), 198.1 (s).

3 0 0

Methyl 3-oxo-7-octenoate (300).103 To a suspension of 0.80 g (20 mmol) of

60% sodium hydride in 30 mL of tetrahydrofuran cooled to 0°C was added dropwise 1.16 g (10 mmol) of methyl acetoacetate (299). The mixture was stirred at 0°C for 10 minutes, cooled to -

10°C and 8.4 mL (12 mmol) of n-butyllithium (1.43 M solution in hexanes) was added slowly.

The mixture was stirred at -10°C for 20 minutes and 0.35 g (12.5 mmol) of 4-bromo-1-butene was added. The resulting mixture was stirred at room temperature for 6 h and poured into a separatory funnel containing 100 mL of ether and 100 mL of a saturated aqueous solution of ammonium chloride. The aqueous layer was extracted with three 100-mL portions of ether. The combined organic extracts were dried (MgSO^, concentrated in vacuo, and the oily residue was purified by chromatography over 30 g of silica gel (eluted with hexanes-ethyl acetate, 18:1) to afford 0.91 g (54%) of 300 as a pale yellow oil: 1H NMR (CDCI3, 250 MHz) 81.67 (m, 2H, CH2),

2.03 (m, 2H, =CCH2), 2.51 (t, J = 7.3 Hz, 2 H, CH2CO), 3.41 (s, 2 H, COCH2COOMe), 3.70 (s,

3H, OCH3), 4.92-5.02 (m, 2H, =CH2), 5.64-5.80 (m, 1H, =CH). o o 168

302

ferf-Butyl 3-oxo-7-octenoate (302). To a suspension of 0.32 g (8 mmol) of 60%

sodium hydride in 12 mL of tetrahydrofuran chilled in an ice bath was added dropwise 0.633 g (4

mmol) of ferf-butyl acetoacetate (301). The mixture was stirred at 0°C for 10 min, cooled to -

10°C and 3.7 mL (4.8 mmol) of o-butyllithium (1.3 M solution in hexanes) was added slowly. The

mixture was stirred at -10°C for 10 min and 0.675 g (5 mmol) of 4-bromo-1-butene was added.

The mixture was stirred at room temperature for 18.5 h, poured into 50 mL of saturated aqueous

ammonium chloride and extracted with three 100-mL portions of diethyl ether. The combined

organic extracts were dried (MgS 0 4 ) and concentrated in vacuo. The residue was purified by

column chromatography over silica gel (eluted with ethyl acetate-hexanes, 1:20) to yield 0.584 g

(69%) of 302 as a pale yellow oil: IR (neat) 1736,1715,1642 crrr1; 1H NMR (CDCI 3, 200 MHz) 8

1.45 (S, 9H, C(CH3)3), 1.68 (m, 2H, CH2), 2.05 (m, 2H, =CCH2), 2.52 (t, J= 7.3 Hz, 2H, CH2CO),

3.32 (s, 2H, COCH2CO), 4.87-5.06 (m, 2 H, =CH2), 5.65-5.85 (m, 1H, =CH); 13q NMR (CDCI3,

62.9 MHz) 8 22.4 (t), 27.9 (q), 32.8 (t), 42.0 (t), 50.7 (t). 81.8 (s), 115.3 (t), 137.8 (d), 166.4 (s),

203.1 (s); exact mass calcd. for C i 2H2q03 m/e 212.1412, found m/e 212.1404.

o \ TBDMSO^

3 0 3

(S)-(-)-ferf-Butyl 2-[Af-(methoxymethyl)-5-(ferf-butyldlmethylsUyloxyme- thyl)-2-pyrrolidinylldene]-3-oxo-7-octenoate (303). To a mixture of 0.826 g (1.92

mmol) of salt 298 and 0.637 g (4.61 mmol) of potassium carbonate was added a solution of

0.488 g (2.30 mmol) of ester 302 in 2.3 mL of A/,A/-dimethylformamide. The mixture was stirred 169 at room temperature under argon for 24 h and partitioned between 50 mL of water and 50 mL of dichloromethane. The aqueous layer was extracted with three 30-mL portions of dichloromethane. The combined organic extracts were dried (MgS04), and concentrated in vacuo. The residual A/,/V-dimethylformamide was removed at 1 mm and the residue was purified by column chromatography over 40 g of silica gel (eluted with ethyl acetate-hexanes, 1:9) to afford 0.262 g (29%) of vinylogous urethane 3 0 3 as pale yellow oil: [ ocJd -25.0° (CHCI3); IR

1692,1641 cm-1; 1H NMR (CDCI 3 , 300 MHz) 50.05 (s, 6 H, Si(CH3)2). 0.87 (s, 9H, SiC(CH 3)3),

1.49 (s, 9H, C(CH3)3), 1.65-1.77 (m, 3H, H4-and H 4), 1.98-2.11 (m, 3H, H * and CH 2C=), 2.41-

2.73 (m, 2H, CH2CO), 2.84-2.95 (m, 1H, H 30, 3.15 (s. 3H, OCH3), 3.29-3.48 (m, 1H, H30, 3.55

(dd, J= 10.3, 5.5 Hz, 1H, CH2OSi), 3.66 (dd, J= 10.3, 5.1 Hz, 1H, CH2OSi), 3.90-3.98 (m, 1H,

NCH), 4.40 (d, J = 10.3 Hz, 1H, NCH20), 4.63 (d, J= 10.3 Hz, 1H, NCH20), 4.92-5.03 (m, 2H,

=CH2), 5.73-5.87 (m, 1H, =CH); 13C NMR (CDCI3, 62.9 MHz) 5 -5.6 (q), 18.1 (s), 23.2 (t), 24.4

(t), 25.8 (q), 28.3 (q), 33.6 (t), 34.0 (t), 41.9 (t), 55.5 (q), 64.5 (t), 64.8 (d), 79.7 (t), 79.8 (s),

103.8 (s), 114.6 (t), 138.6 (d), 165.4 (s), 168.3 (s), 199.8 (s); exact mass calcd. for

C2sH45N0 5Si m/e 467.3067, found m/e 467.3060.

TB D M SO ^^

OMe MeO

3 0 4

(S)-(-)-Methyl 2-[A/-(methoxymethyl)-5-(ferf-butyldimethylslloxymethyl)-

2-pyrrolidinylidene]-3-oxo-7-octenoate (304). To a mixture of 4.31 g (10 mmol) of salt

298 and 3.32 g (24 mmol) of potassium carbonate under argon was added a solution of 2.04 g

(12 mmol) of ester 301 in 24 mL of A/,/\/-dimethylformamide. The mixture was stirred at room temperature for 28 h and partitioned between 250 mL of water and 250 mL of dichloromethane.

The aqueous layer was extracted with three 100-mL portions of dichloromethane. The combined organic extracts were dried (MgS04), and concentrated in vacuo. The residual N,N- 170 dimethylformamide was removed at 1 mm and the residue was purified by column chromatography over silica gel (eluted with acetone-hexanes, 1:10) to afford 1.58 g (37%) of vinylogous urethane 304 as pale yellow oil: [a]p -26.3° (CHCI 3); IR 1701,1639 cm’ 1; 1H NMR

(CDCIg, 300 MHz) 60.04 (s, 6H, Si(CH3)2), 0.86 (s, 9H, SiC(CH3)3), 1.60-1.82 (m, 3H, H4-and

H4), 1.99-2.14 (m, 3H, H4- and CH 2C=), 2.29-2.73 (m, 2 H, CH2CO), 2.85-3.07 (m, 1H, H3-), 3.13

(s, 3H, OCH3), 3.39-3.58 (m, 1H, H3-), 3.60-3.77 (m, 2H, CH2OSi), 3.68 (s, 3H, COOCH3), 3.90-

4.01 (m, 1H, NCH), 4.36 (d, J = 10.3 Hz, 1H, NCH20), 4.64 (d, J = 10.3 Hz, 1H, NCH20), 4.83-

5.04 (m, 2H, =CH2), 5.68-5.90 (m, 1H, =CH); 13C NMR (CDCI3, 62.9 MHz) 8 -5.6 (q), 18.1 (s),

22.9 (t), 24.5 (t), 25.7 (q), 33.4 (t), 34.4 (t), 41.6 (t), 50.9 (q), 55.5 (q), 64.5 (t), 64.8 (d), 79.6 (t),

101.2 (s), 114.5 (t), 138.7 (d), 167.3 (s), 169.2 (s), 199.5 (s); exact mass calcd. for

C22 H39 N0 5Si m/e 425.2597, found m/e 425.2591.

^COOEt TBDMSO.. ^ N CN MeO

3 0 5

(S)-(*)-Ethyl a-cyano a-[N-(methoxymethyl)-5-(ter/-butyldlmethylsilylo- xym ethyl)-2-pyrrolidinylidene]acetate (305). To a mixture of 12.93 g (30 mmol) of salt

298 and 9.95 g (72 mmol) of potassium carbonate under argon was added a solution of 4.07 g

(36 mmol) of ethyl cyanoacetate in 72 mL of /V./V-dimethylformamide. The mixture was stirred at room temperature for 20 h and partitioned between 750 mL of dichloromethane and 750 mL of water. The aqueous layer was extracted with 4 300-mL portions of dichloromethane. The combined organic extracts were dried (MgS04), concentrated in vacuo and the residue was purified by chromatography over 200 g of silica gel (eluted with hexanes-ethyl acetate, 1 :1) to afford 8.04 g (73%) of 305 as a pale yellow oil: [a]D -47.0° (CHCI3, 200 MHz): IR (neat) 2202,

1702 cm '1; 1H NMR (CDCI3) 5 0.038 (s, 3H, CH 3 Si), 0.042 (s, 3H, CH3Si), 0.86 (s, 9H,

SiC(CH3)3), 1.28 (t, J = 7.1 Hz, 3H, CH3), 1.80-1.96 (m, 1H, H4), 2.00-2.16 (m, 1H, H4), 3.08- 171 3.28 (m, 1H, =CCH2), 3.37 (s, 3H, OCH3), 3.39-3.58 (m, 1H, =CCH2), 3.60-3.65 (m, 1H,

CH2OSi), 3.70-3.75 (m, 1H, CH2OSi), 3.93-4.03 (m, 1H, CHN), 4.17 (q, J = 7.1 Hz, 2H, OCH2),

4.94 (d, J = 10.4 Hz, 1H, NCH20), 5.43 (d, J= 10.2 Hz, 1H, NCH20); 13C NMR (CDCI3, 62.9

MHz) 8 -5.6 (q), 14.4 (q), 18.1 (s), 23.0 (t), 25.7 (q), 35.0 (t), 55.3 (q), 60.3 (t), 64.0 (t), 66.7 (d),

69.6 (s), 76.5 (t), 118.8 (s), 166.1 (s), 172.4 (s); exact mass calcd. for C 18 H32N20 4Si m/e

368.2133, found m/e 368.2146.

.COOEt

3 0 6

(S)-(-)-Ethyl a-cyano a-[W-(methoxymethyl)-5-(hydroxymethyl)-2-pyrroll- dinylldene]acetate (306). To a solution of 787 mg (2.14 mmol) of the ferf-butyfdimethylsilyl ether 305 in 4 mL of tetrahydrofuran cooled in an ice bath was added 4.3 mL (4.28 mmol) of a

1.0 M solution of tetrabutylammonium fluoride in tetrahydrofuran. The mixture was stirred 10 min at 0°C and 75 min at room temperature, diluted with 40 mL of dichloromethane and washed with 40 mL of water. The aqueous wash was extracted with four 40-mL portions of dichloromethane. The combined organic extracts were dried (MgS04) and concentrated in vacuo. The residue was purified by column chromatography over 20 g of silica gel (eluted with ethyl acetate-hexanes, 4:1) to afford 484 mg (89%) of alcohol 306 as a white solid: mp 95-

97°C; [ct]D -169.1° (CHCI 3): IR (CHCI3) 2204,1699 cm’1; 1H NMR (CDCI 3 , 200 MHz) 8 1.26 (t,

J= 7.1 Hz, 3H, CH3), 1.79-2.20 (m, 2H, H4), 3.09 (t, J= 6.7 Hz, 1H, OH), 3.14-3.39 (m, 2H,

=CCH2), 3.41 (s, 3H, 0 CH3), 3.44-3.62 (m, 1H, CH2OH), 3.71-3.82 (m, 1H, CH 2OH), 3.85-3.96

(m, 1H, CHN), 4.15 (q, J= 7.1 Hz, 2H, CH20), 4.78 (d, J= 9.9 Hz, 1H, NCH 20), 5.38 (d, J= 9.9

Hz, 1H, NCH20); 13C NMR (CDCI3, 62.9 MHz) 5 14.3 (q), 22.8 (t), 34.7 (t), 54.8 (q), 60.4 (t), 63.5

(t), 68.7 (d), 70.1 (s), 76.5 (t), 118.4 (s), 165.8 (s), 172.5 (s); exact mass calcd. for C 12H18 N20 4 172 m/e 254.1268, found m/e 254.1277. Anal, calcd. for C i 2H18 N20 4 : C, 56.68; H, 7.13. found C,

56.76; H, 7.19.

.COOEt

3 0 7

(SM-)-Ethyl a-cyano a-[N-(methoxymethyl)-5-(methylsulfonyloxymethyl)-2-pyrrolidinylldene]acetate (307). To a solution of 3.34 g (13.2 mmol) of alcohol

306 in 80 mL of dichloromethane cooled in an ice bath was added successively 2.00 g (19.7

mmol) of triethylamine and 1.96 g (17.1 mmol) of methanesulfonyl chloride. A catalytic amount of 4-dimethylaminopyridine was then added and the mixture was stirred at room temperature for

13 h. The mixture was partitioned between 350 mL of dichloromethane and 350 mL of water.

The organic layer was washed successively with 250 mL of 10% hydrochloric acid, 250 mL of

saturated aqueous sodium bicarbonate, 250 mL of brine, dried (MgS04) and concentrated in vacuo. The residue was purified by column chromatography over 80 g of silica gel (eluted with

ethyl acetate-hexanes, 3:1) to afford 3.87 g (87%) of mesylate 307 as a white solid: mp 105-

108°C; [a]D-138.7° (CHCI3); IR (CHCI3) 2206,1702 cm’ 1; 1H NMR (CDCI3, 250 MHz) 5 1.30 (t,

J= 7.1 Hz, 3H, CH3), 1.92-2.04 (m, 1H, H4), 2.11-2.28 (m, 1H, H4), 3.04 (s, 3H, CH 3S), 3.16-

3.31 (m, 1H, H3), 3.40 (s, 3H, CH30), 3.46-3.59 (m, 1H, H3), 4.11-4.20 (m, 3H, CH20 and CHN),

4.23-4.39 (m, 2H, CH 2OMs), 5.11 (d, J= 10.2 Hz, 1H, NCH20), 5.20 (d, J= 10.2 Hz, 1H,

NCH20); 13C NMR (CDCI3, 62.9 MHz) 8 14.3 (q), 22.9 (t), 34.2 (t), 37.6 (q), 55.1 (q), 60.6 (t),

64.5 (d), 68.8 (t), 71.2 (s), 76.9 (t), 117.9 (s), 165.5 (s), 171.7 (s); exact mass calcd. for

C i3H20N2O6S m/e 332.1043, found m/e 332.1030. 173

... Hv / CCX3Et nc^ ’^ n/T j CN MeO

3 0 8

(SM-)-Ethyl a-cyano a-[N-(methoxymethyl)-5-(cyanomethyl)-2-pyrrolldl- nylldene]acetate (308). To a solution of 3.87 g (11.6 mmol) of mesylate 307 in 39 mL of dimethylsulfoxide was added 1.14 g (23.3 mmol) of sodium cyanide. The mixture was stirred at room temperature for 38 h, at 55°C for 10h and at 35°C for 14 h. The mixture was diluted with

500 mL of water and extracted with five 350-mL portions of dichloromethane. The combined organic extracts were washed with three 500-mL portions of water and the combined aqueous washes were extracted with three 500-mL portions of dichloromethane. The combined organic extracts were dried (MgS04) and concentrated in vacuo. The residue was purified by chromatography over 80 g of silica gel (eluted with acetone-hexanes, 1:3) to afford 1.94 g (63%) of nitrile 308 as a white solid: mp 115-116°C; [ct]D -43.8° (CHCI3); IR (CHCI3) 2207,1703 cm ' 1 ;

1H NMR (CDCI3, 200 MHz) 51.30 (t, J= 7.1 Hz, 3H, CH3), 1.87-2.03 (m, 1H, H4), 2.22-2.42 (m,

1H, H4), 2.62-2.86 (m, 2 H, CH2CN), 3.27-3.61 (m, 2H, =CCH2), 3.42 (s, 3H, CH30), 4.08-4.25

(m, 3H, CH20 and CHN), 5.10 (d, J= 10.5 Hz, 1H, NCH2 0), 5.26 (d, J= 10.5 Hz, 1H,

NCH20 );13C NMR (CDCI3, 62.9 MHz) 514.3 (q), 22.9 (t), 25.8 (t), 33.6 (t), 55.4 (q), 60.7 (t), 62.1

(d), 71.9 (s), 76.7 (t), 116.2 (s), 117.8 (s), 165.4 (s), 171.1 (s); exact mass calcd. for

C i3H t7N30 3 m/e 263.1271, found m/e263.1281. Anal, calcd. forC-| 3H i7N30 3 : C, 59.30; H,

6.51. found C, 59.08; H, 6.54. 174 .COOEt

H CN

3 0 9

(S)-(+)>Ethyl a-cyano a-[5-(cyanomethyl)-2-pyrrolldlnyiidene]acetate

(309). To a solution of 526 mg (2.0 mmol) of nitrile 308 in 7 mL of tetrahydrofuran was added

0.5 mL of concentrated hydrochloric acid. The mixture was stirred at 50°C for 17 h, diluted with

150 mL of dichloromethane, washed successively with 100 mL of water, 100 mL of saturated aqueous sodium bicarbonate, 100 mL of brine, dried (MgS 0 4 ) and concentrated in vacuo. The solid residue was purified by recrystallization from ethyl acetate-hexanes to afford 420 mg (96%) of nitrile 309 as a white solid: mp 158-160°C; [cfo +3.9° (CHCI 3); IR (CHCI3) 3317, 2212,1673 cm-1 ; 1H NMR (CDCI3, 250 MHz) 8 1.31 (t, J= 7.1 Hz, 3H, CH3), 1.90-2.02 (m, 1H, H4), 2.37-

2.52 (m, 1H, H4), 2.67 (d, J= 5.7 Hz, 2H, CH2CN), 2.92 3.20 (m, 2H, =CCH2), 4.21 (q, J = 7.1

Hz, 2H, CH20), 4.26-4.34 (m, 1H, CHN), 9.10 (brs, 1H, NH); 13C NMR (CDCI 3, 62.9 MHz) 814.3

(q), 24.3 (t), 26.6 (t), 32.3 (t), 57.4 (d), 60.7 (t), 69.6 (s), 115.9 (s), 117.7 (s), 167.5 (s), 172.9 (s); exact mass calcd. for C 11H i3 N3 0 2 m/e 219.1009, found m/e 219.1038. Anal, calcd. for

C11H13N30 2 : C, 60.26; H, 5.98. found C, 59.99; H, 5.96.

,COOEt

MeO

3 1 0

Ethyl 2,8-dicyano-3-(methoxymethylamino)-2-(E)-heptenoate (310). To

15 mL of ammonia stirred at -78°C was added 35 mg of lithium metal. Once all the lithium was dissolved, a solution of 526 mg (2.0 mmol) of nitrile 308 and 133 mg (1.8 mmol) of dry ferf-butyl alcohol in 7 mL of tetrahydrofuran was added dropwise. After 30 min stirring, the reaction mixture was quenched by addition of solid ammonium chloride, and then stirred at room 175 temperature for 2 h while the ammonia evaporated. The residue was dissolved in 40 mL of water and extracted with four 60-mL portions of dichloromethane. The combined organic extracts were dried (MgS 0 4 ) and concentrated in vacuo. The residue was purified by column chromatography over 10 g of silica gel (eluted with acetone-hexanes, 1:3) to afford 247 mg

(47%) of recovered starting material and 39 mg ( 8 %) of 310 as a colorless oil: IR (neat) 2247,

2207,1671 cm'1; 1H NMR (CDCI3, 200 MHz) 51.32 (t, J= 7.1 Hz, 3H, CH3), 1.81-1.90 (m, 4H,

Hs and H6), 2.42 (t, J= 6.5 Hz, 2H, CH2CN), 2.70 (m, 2H, CH2CO), 3.65 (s, 3H, CH30), 4.22 (q,

J= 7.1 Hz, 2H, CH20), 4.65 (d, J= 6.5 Hz, 2H, NCH20), 10.34 (brs, 1H, NH); 13C NMR (CDCI 3,

62.9 MHz) 5 14.2 (q), 16.8 (t), 25.0 (t), 27.3 (t), 29.8 (t), 55.6 (q), 60.8 (t), 74.6 (t), 74.7 (s), 118.0

(s), 119.0 (s), 168.1 (s), 173.7 (s); exact mass calcd. for C 13Hig N30 3 m/e 265.1426, found m/e

265.1432.

TBDMSO

321

(S)-(+)-1-[W-(Methoxymethyl)-5-[(ferf-butyldlmethylsiloxy)methyl]-2-pyrrolldl- nylidene]- 2 -propanone (321). To a solution of 2.00 g (6.92 mmol) of thiolactam 297 in

6.5 mL of dichloromethane was added 1.42 g (10.4 mmol) of bromoacetone .110 The mixture was stirred at room temperature for 3.7 h. The solution was diluted with 32 mL of dichloromethane and 2.72 g (10.4 mmol) of triphenylphosphine was added, followed by 2.10 g

(20.8 mmol) of triethylamine. The resulting mixture was stirred at room temperature for 16 h, diluted with 60 mL of dichloromethane, and washed with 1M aqueous sodium dihydrogen phosphate. The aqueous wash was extracted with three 60-mL portions of dichloromethane.

The combined organic extracts were dried (MgS04), concentrated in vacuo, and the residual oil was purified by column chromatography over 40 g of silica gel (eluted with acetone-hexanes,

1:4) to afford 1.52 g (69%) of vinylogous amide 321 as a pale yellow oil: [oi]d+94.2 0 (CHCI3); IR (neat) 1654 cm'1; 1H NMR (CDCI3, 250 MHz) 8 0.02 (s, 6 H, Si(CH3)2), 0.85 (s, 9H, SiC(CH3)3),

1.76-1.86 (m, 1H, H4.), 1.93-2.12 (m, 1H, H4.), 2.06 (s, 3H, COCH3), 2.97-3.14 (m, 1H, =CCH2),

3.21-3.39 (m, 1H, =CCH2), 3.29 (S, 3H, OCH3), 3.57 (d, J= 1.5 Hz, 1H, CH2OSi), 3.60 (s. 1H,

CH2OSi), 3.65-3.80 (m, 1H, CHN), 4.63 (d, J= 10.4 Hz, 1H, NCH20), 4.70 (d, J= 10.4 Hz, 1H,

NCH20), 5.33 (s, 1H, =CH); 13C NMR (CDCI3, 62.9 MHz) 8 -5.63 (q), -5.58 (q), 18.1 (s), 24.5 (t),

25.7 (q), 30.9 (q), 31.7 (t), 55.8 (q), 64.1 (d), 64.7 (t), 76.5 (t), 91.9 (d), 165.6 (s), 195.3 (s); exact mass calcd. for C-) 6H31 N03Si m/e 313.2073, found m/e 313.2079.

CHzPh

TBDM SO^

MeO J

3 2 2

1-[A/*(Methoxymethyl)*3-benzyl*5-(ferf

16 h and poured into a separatory funnel containing 30 mL of saturated aqueous ammonium chloride and 75 mL of ether. The aqueous layer was extracted with three 45-mL portions of ether and the combined organic extracts were dried (MgS04) and concentrated in vacuo. The residue was purified by chromatography over 10 g of silica gel (eluted with acetone-hexanes,

1:4) to afford 106 mg (35%) of recovered starting material 321 and 13 mg (34%) of vinylogous amide 322 as a 2.5:1 mixture of diastereoisomers: IR (neat) 1718,1647 cm'1; 1H NMR (CDCI3,

200 MHz) signals from major diastereomer 8 0.03 (s, 6H, Si(CH3)2), 0.87 (s, 9H, SiC(CH3)3),

1.50-1.63 (m, 1H, H4>), 1.78-1.85 (m, 1H, H4.), 2.16 (s, 3H, COCH3), 2.38 (dd, J= 13.0,10.5 Hz,

1H, PhCH2), 3.18 (dd, J= 13.0, 2.8 Hz, 1H, PhCH2), 3.32 (s, 3H, OCH3), 3.55-3.78 (m, 3H, 177 CHCH2OSi), 4.02-4.11 (m, 1H, H3.), 4.68 (d, J= 10.3 Hz, 1H, NCH20), 4.72 (d, J = 10.3 Hz, 1H,

NCH20), 5.40 (s, 1H, =CH), 7.15-7.42 (m, 5H, ArH); The following peaks were attributed to the minor isomer: 2.63-2.69 (m, 1H, PhCH2), 2.89-2.96 (m, 1H, PhCH2), 3.28 (s, 3H, OCH3), 5.32

(s, 1H, =CH); 13c NMR (CDCI3, 75.5 MHz) 5 -5.6 (q), 18.1 (s), 25.7 (q), 28.7 (t), 31.2 (q), 38.5 (t),

44.1 (d), 55.9 (q), 61.8 (d), 64.5 (t), 76.0 (t), 91.6 (d), 126.1 (d), 128.2 (d), 129.4 (d), 140.3 (s),

169.7 (s), 194.5 (s); Smaller peaks in the 13C NMR spectrum were attributed to the minor isomer; exact mass calcd. for C23H37N03Si m/e 403.2543, found m/e 403.2547.

TBDMSO s O N J . Me l Me

3 2 3

(+)-1-[(2/7 or S, 5S)-5-[(ferr-Butyldimethylsiloxy)methyl]-1-methyl-2-pyr- rolldlnyl]-2-propanone (323). To a solution of 317 mg (1.0 mmol) of vinylogous amide

321 in 5 mL of dry methanol stirred at room temperature was added a trace of bromocresol green and 95 mg (1.5 mmol) of sodium cyanoborohydride. A dry solution of hydrochloric acid in methanol was then added dropwise until the reaction color went from blue to yellow (pH 4) and was added as needed to maintain a pH of 4 throughout the next 20 min. The reaction mixture was neutralized by addition of 10 M aqueous potassium hydroxide, diluted with 15 mL of water and extracted with four 25-mL portions of dichloromethane. The combined organic extracts were dried (MgSC> 4 ) and concentrated in vacuo. The residue was purified by column chromatography over 15 g of silica gel (eluted with acetone-hexanes, 1:5) to afford 134 mg

(45%) of p-aminoketone 323 as a pale yellow oil: [oc]d +14.7° (CHCI3); IR (neat) 1716 cm'1; 1H

NMR (CDCI3, 250 MHz) 8 0.04 (s, 6H, Si(CH3)2), 0.89 (s, 9H, SiC(CH3)3), 1.25-1.36 (m, 1H),

1.41-1.54 (m, 1H), 1.78-2.03 (m, 2H), 2.15 (s, 3H, NCH3), 2.34 (s, 3H, OCH3), 2.37-2.53 (m,

2H), 2.7-2.8 (m, 2H), 3.41 (dd, J= 10.0, 6.7 Hz, 1H, CH2OSi), 3.64 (dd, J= 10.0, 5.4 Hz, 1H,

CH2OSi); 13C NMR (CDCI3, 62.9 MHz) 8 -5.3 (q), 18.3 (s), 25.9 (q), 26.8 (t), 29.9 (t), 31.0 (q), 178 40.4 (q), 48.8 (t), 63.6 (d), 67.0 (t), 67.9 (d), 208.2 (s); exact mass calcd. for C i 5 H3iN 0 2Si m/e

285.2125, found m/e 285.2135.

3 2 5

Ethyl 2-acetyl*5-hexenoate (325).112 To 36 mL of ethanol was added 1.64 g

(71.4 mmol) of sodium metal over 3h. The resulting solution of sodium ethoxide in ethanol was cooled to 0°C and 10.41 g (80.0 mmol) of ethyl acetoacetate (324) was added dropwise. The solution was stirred at room temperature for 1.5 h and 9.65 g (71.4 mmol) of 4-bromo-1-butene was added. The reaction mixture was heated at reflux with stirring overnight and concentrated in vacuo. The residue was dissolved in 400 mL of water and extracted with three 500-mL portions of ether. The combined ether extracts were dried (MgS04) and concentrated in vacuo.

The residue was purified by distillation under reduced pressure to afford 8 .86 g (67%) of p- ketoester 325 as a clear oil: bp 130-134°C (20 mm); 1H NMR (CDCI3, 200 MHz) 81.27 (t, J= 7.1

Hz, 3H, CH3), 1.88-2.17 (m, 4H, CH 2CH2), 2.23 (s, 3H, CH3 CO), 3.44 (t, J = 6.9 Hz, 1H,

CHCOOEt), 4.20 (q, J= 7.1 Hz, 2H, CH20), 4.98-5.08 (m, 2 H, =CH2), 5.65-5.85 (m, 1H, =CH);

13C NMR (CDCI3) 8 14.1 (q), 27.1 (t), 29.0 (q), 31.3 (t), 58.9 (d), 61.3 (t), 116.0 (t), 137.0 (d),

169.7 (s), 203.0 (s).

3 2 6

6-Hepten-2-one (326).112 To a solution of 5.70 g (31 mmol) of p-ketoester 325 in

72 mL of ethanol was added 62 mL (0.310 mol) of 5 M aqueous potassium hydroxide. The 179 mixture was stirred at room temperature overnight, acidified to pH 2 with 10% aqueous sulfuric acid and warmed at reflux for 2 h. The solution was cooled, diluted with 400 mL of water and extracted with three 400-mL portions of ether. The combined organic extracts were dried

(MgS0 4 ) and concentrated in vacuo. The residue was purified by column chromatography over

50 g of silica gel (eluted with ethyl acetate-hexanes, 1:16) to afford 2.67 g (77%) of ketone 326 as a pale yellow oil: 1H NMR (CDCI3, 300 MHz) 5 1.65 (p, J = 7 Hz, 2H, CH2), 2.02 (m, 2H,

=CCH2), 2.11 (s, 3H, CH3CO), 2.41 (t, J= 7.4 Hz, 2 H, COCH2), 4.92-5.03 (m, 2 H, =CH2), 5.66-

5.83 (m, 1H, =CH).

1-Diazo-6-Hepten-2-one (327). To a solution of 714 mg (17.8 mmol) of 60% sodium hydride and 90 mL of ethanol in 36 mL of ether cooled to 0°C was added dropwise a mixture of 2.00 g (17.8 mmol) of 6-hepten-2-one (326) and 1.98 g (17.8 mmol) of ethyl formate.

The reaction mixture was stirred 1 h at 0°C, 4 h at room temperature and 36 mL of ethanol was added after standing overnight. The thick mixture was stirred an additional hour at room temperature. The solid was then collected under argon and dried in vacuo to afford 1.71 g

(59%) of the sodium anion of 1-formyl-6-hepten- 2-one. To a suspension of this solid in 24 mL of ethanol stirred at 0°C was added dropwise 1.89 g (9.59 mmol) of tosyl azide .37 The reaction mixture was stirred at 0°C for 15 min and at room temperature for 3 h. The solvent was removed in vacuo and the residue was diluted with 30 mL of water. The aqueous layer was extracted with

60 mL of ether. The organic extract was washed successively with 25 mL of 1 M aqueous sodium hydroxide and 30 mL of water, dried (Na 2S04) and concentrated in vacuo. The yellow residue was purified by column chromatography over 10 g of silica gel (eluted with ethyl acetate- hexanes, 1:10) to afford 561 mg (42%) of diazoketone 327 as a yellow oil: 1H NMR (CDCI 3, 200 180 MHz) 5 1.71 (p, J = 7.2 Hz, 2H, CH2), 2.08 (m, 2H, =CCH2), 2.23-2.38 (m, 2 H, CH2CO), 4.94-

5.06 (m, 2H, =CH2), 5.23 (br s, 1H, CH=N2), 5.65-5.87 (m, 1H, =CH).

O Br

3 2 8

1-Bromo-6-Hepten>2-one (328).113 To a solution of 561 mg (4.06 mmol) of diazoketone 327 in 14 mL of ether stirred at 0°C was added dropwise 3.7 mL (32.5 mmol) of

47% hydrobromic acid. The mixture was stirred for 1.5 h at room temperature and poured into a separatory funnel containing 200 mL of brine. This solution was extracted with three 150-mL portions of ether. The combined organic extracts were washed successively with 200 mL of saturated sodium bicarbonate and 200 mL of brine, dried (MgSC> 4) and concentrated in vacuo.

The residue was purified by column chromatography over 10 g of silica gel (eluted with ethyl acetate-hexanes, 1:14) to afford 520 mg (67%) of bromoketone 328 as a pale yellow oil: 1H

NMR (CDCI3 , 300 MHz) 8 1.73 (m, 2H, CH2), 2.08 (m, 2H, =CCH2), 2.66 (t. J= 7.3 Hz, 2H,

CH2CO), 3.87 (s, 2H, CH 2Br), 4.96-5.07 (m, 2H, =CH2), 5.68-5.84 (m, 1H, =CH).

33 0

Ethyl 3-lodopropanoate (330).137 To a solution of 19.92 g (140 mmol) of ethyl 3- chloropropanoate (329) in 490 mL of acetone were added 84.9 g (560 mmol) of sodium iodide.

The reaction mixture was heated at reflux for 24 h and concentrated in vacuo. The residue was dissolved in 800 mL of ether. This solution was washed with three 300-mL portions of water and the combined aqueous washes were extracted with three 300-mL portions of ether. The 181 combined organic extracts were dried (MgS04) and concentrated in vacuo. The brown residue was purified by distillation under reduced pressure to afford 30.83 g (97%) of ester 330 as a yellow oil: bp 67-72°C (6 mm); 1H NMR (CDCI3, 200 MHz) 8 1.25 (t, J= 7.1 Hz, 3H, CH3), 2.93 (t,

J= 7.0 Hz, 2 H, CH2CO), 3.30 (t, J= 7.0 Hz, 2H, CH2I). 4.15 (q, 7.1 Hz, 2 H, CH20).

331

Ethyl 5-hexenoate (331 ) . 138 To a solution of 6.84 g (30.0 mmol) of ethyl 3- iodopropanoate (330) in 80 mL of tetrahydrofuran was added 3.83 g (44.0 mmol) of N,N- dimethylacetamide and 3.00 g (46.0 mmol) of Zn-Cu couple139. The mixture was stirred at 60°C during 3 hours. Meanwhile, a solution of allyl tosylate in tetrahydrofuran was prepared in the following way: To a solution of 1.39 g (24.0 mmol) of allyl alcohol in 50 mL of terahydrofuran stirred at -78°C was added 17.7 mL (24.0 mmol) of n-butyllithium (1.36 M solution in hexanes).

The solution was stirred at -78°C for 30 min, placed in an ice-water bath, 4.58 g (24.0 mmol) of p- toluenesulfonyl chloride was added and the resulting mixture was stirred at 0°C for 1 hr. The solution was diluted with 41 mL of tetrahydrofuran and 358 mg (4.0 mmol) of copper cyanide was added, followed by the solution of organozinc compound. The reaction mixture was stirred at 60°C for 1 h, diluted with 750 mL of ether and washed with 300 mL of saturated aqueous sodium bicarbonate. The aqueous wash was extracted with 300 mL of ether. The combined organic extracts were dried (MgS04) and concentrated in vacuo. The crude oil was purified by column chromatography over 50 g of silica gel (eluted with dichloromethane-hexanes, 1:2) to yield 2.63 g (77%) of ester 331 as a pale yellow o il:1H NMR (CDCI3, 250 MHz) 81.24 (t, J = 7.1

Hz, 3H, CH3), 1.65-1.77 (m, 2H, CH2), 2.03-2.12 (m, 2H, =CCH2), 2.29 (t, J= 7.5 Hz, 2H,

CH2CO), 4.11 (q, J= 7.1 Hz, 2H, CH20), 4.94-5.05 (m, 2H, =CH2), 5.69-5.85 (m, 1H, =CH). 182

3 3 2

5-Hexenoic acid (332).140 To a solution of 2.59 g (18 mmol) of ester 331 in 43 mL of ethanol was added 55 mL of 5 M aqueous potassium hydroxide. The mixture was stirred at room temperature for 18 h, acidified with 10% aqueous sulfuric acid and extracted with three

200-mL portions of ether and two 150-mL portions of pentane. The combined organic extracts were dried (MgS04), concentrated in vacuo and the residue was purified by column chromatography over 30 g of silica gel (eluted with hexanes-ethyl acetate, 5:1) to afford 1.60 g

(77%) of carboxylic acid as a colorless oil: 1H NMR (CDCI3, 200 MHz) 6 1.74 (m, 2H, CH2), 2.11

(dq, J= 7.3, 1.2 Hz, 2H, =CCH2), 2.37 (t, J= 7.5 Hz, 2 H, CH2CO), 4.97-5.08 (m, 2H, =CH2),

5.70-5.86 (m, 1H, =CH), 10.0 (very br s, 1H, OH).

3 3 3

5-Hexenoyl chloride (37 ).140 To 7.69 g (67.4 mmol) of 5-hexenoic acid (333) under argon at 0°C was added 11.9 g (100 mmol) of thionyl chloride dropwise over 15 min. The mixture was stirred at 0°C for 1.5 h, at reflux for 1 h and concentrated in vacuo. The residual oil was purified by distillation under reduced pressure to afford 6.23 g (70%) of acid chloride 333 as a colorless oil: bp 59-61°C (22 mm); 1H NMR (CDCI3, 250 MHz) 8 1.82 (p, J= 7.1 Hz, 2H,

CH2), 2.13 (m, 2H, =CCH2), 2.90 (t, J= 7.2 Hz, 2H, CH2CO), 5.02-5.10 (m, 2H, =CH2), 5.67-

5.83 (m, 1H, =CH). 3 2 8

1-Bromo-6-Hepten-2-one (328).113 To a 250-mL Erlenmeyer flask containing 26

mL of 40% aqueous potassium hydroxide and 88 mL of ether cooled at 0°C was added in portions over 5 min 8.68 g (84 mmol) of /V-methyl-/V-nitrosourea.133 The mixture was stirred at

0°C until the urea had completely dissolved. The flask was then placed in a dry ice-acetone bath

and the supernatant, a bright yellow ethereal solution, was decanted into another flask and dried

over potassium hydroxide at 0°C for 3 h. To this solution diazomethane in ether stirred at 0°C was added dropwise 3.49 g (26.0 mmol) of 5-hexenoyl chloride (333). The mixture was stirred

at 0°C for 15 min and 26 mL (0.232 mol) of 48% hydrobromic acid in water was added over 10

min. The mixture was stirred at room temperature for 30 min and poured into a separatory funnel

containing 100 mL of brine. The solution was extracted with three 100 mL-portions of ether.

The combined organic extracts were washed successively with 100 mL of saturated sodium

bicarbonate and 100 mL of brine, dried (MgS04) and concentrated in vacuo. The residue was purified by column chromatography over 80 g of silica gel (eluted with ethyl acetate-hexanes,

1:14) to afford 4.40 g (88%) of bromoketone 328 as a colorless oil.

TBDMSO

MeO

3 3 4

(S)-(+)-1-[A/-(Methoxymethyl)-5-[(ferf-butyldImethylsiloxy)methyl]-2-pyr-

rolldinylidene]-6-hepten-2-one (334). To a solution of 1.20 g (4.15 mmol) of thiolactam

297 in 3.8 mL of dichloromethane was added 1.11 g (5.81 mmol) of bromoketone 328. The mixture was stirred in the dark at room temperature for 4 h. The solution was diluted with 20 mL 184 of dichloromethane and 1.63 g (6.22 mmol) of triphenylphosphine was added, followed by 1.26

g (12.4 mmol) of triethylamine. The mixture was stirred at room temperature for an additional 18

h, diluted with 60 mL of dichloromethane and washed with 1M aqueous sodium

dihydrogenphosphate. The aqueous wash was extracted with three 60-mL portions of

dichloromethane. The combined organic extracts were dried (MgS04) and concentrated in

vacuo. The resulting semi-solid residue was purified by column chromatography over 30 g of

silica gel (eluted with hexanes-ethyl acetate, 5:1) to afford 1.03 g ( 68 %) of 334 as a pale yellow

oil: [a]D +76.7° (CHCI3); IR (neat) 1648 cm-1; 1H NMR (CDCI3, 250 MHz) 8 0.031 (s, 3H, SiCH3),

0.033 (S, 3H, SiCH3), 0.87 (s, 9H, SiC(CH3)3), 1.63-1.75 (m, 2H, H4), 1.76-1.86 (m, 1H, H 4.),

1.96-2.12 (m, 3H, H4. and =CCH2), 2.32 (m, 2H, CH2CO), 3.01-3.16 (m, 1H, H3-), 3.30 (s. 3H,

OCH3), 3.26-3.40 (m, 1H, H30 ,3.52-3.72 (m, 2H, CH2OSi), 3.73-3.79 (m, 1H, CHN), 4.65 (d,J =

10.4 Hz, 1H, NCH20), 4.70 (d, J= 10.4 Hz, 1H, NCH20), 4.90-5.04 (m, 2H, =CH2), 5.33 (s, 1H,

=CHCO), 5.72-5.88 (m, 1H, =CH); 13C NMR (CDCI3, 75.5 MHz) 5-5.6 (q), -5.5 (q), 18.1 (s), 24.6

(t), 24.7 (t), 25.8 (q), 31.8 (t), 33.5 (t), 43.0 (t), 55.8 (q), 64.1 (d), 64.7 (t), 76.6 (t), 91.6 (d), 114.5

(t), 138.7 (d), 165.6 (s); exact mass calcd. for C 2oH 37 N0 3Si m/e 367.2543, found m/e

367.2528.

3 3 5

(S)-(-)-1-[A/-(Methoxymethyl)-5-(hydroxymethyl)-2-pyrrolidinylidene]-6-

hepten-2-one (335). To a solution of 949 mg (2.59 mmol) of silyl ether 334 in 55 mL of

tetrahydrofuran cooled to 0°C was added dropwise 3.88 mL (3.88 mmol) of a 1.0 M solution of

tetrabutylammonium fluoride in tetrahydrofuran. The mixture was stirred at 0°C for 15 min, at

room temperature for 30 min, diluted with 60 mL of dichloromethane and washed with 60 mL of water. The aqueous wash was extracted with three 60-mL portions of dichloromethane. The 185 combined organic extracts were dried (MgS04) and concentrated in vacuo. The crude oil was purified by column chromatography over 10 g of silica gel (eluted with ethyl acetate-hexanes,

5:2) to yield 480 mg (74%) of alcohol 335 as a pale yellow oil: [

3384,1637 cnr1; 1H NMR (CDCI3, 200 MHz) 81.59-1.84 (m, 3H, H4. and H4), 1.93-2.15 (m, 3H,

H4. and =CCH2), 2.29-2.44 (m, 2H, CH 2CO), 3.39 (s, 3H, OCH3), 3.06-3.76 (m, 4H, CHCH 2OH),

4.53 (d, J= 10.1 Hz, 1H, NCH20), 4.74 (d, J= 10.1 Hz, 1H, NCH20), 4.91-5.05 (m, 2H, =CH2),

5.33 (S, 1H, =CHCO), 5.69-5.89 (m, 1H, =CH); 13C NMR (CDCI3, 62.9 MHz) 8 24.0 (t), 24.6 (t),

31.8 (t), 33.4 (t), 42.9 (t), 56.0 (q), 64.6 (t), 65.8 (d), 77.2 (t), 91.9 (d), 114.6 (t), 138.6 (d), 165.3

(s), 198.1 (S).

k OMe

3 3 6

(S)-(+)-N-(Methoxymethyl)>5-(benzyloxymethyl)pyrrolidine-2-thione

(336). To a solution of 2.67 g (15.25 mmol) of alcohol 287 in 91 mL of benzene stirred at room temperature was added successively 9.65 g (76.23 mmol) of benzyl chloride, 45 mL of 50% aqueous sodium hydroxide and 0.534 g (1.53 mmol) of tetrabutylammonium hydrogensulfate.

The mixture was vigorously stirred at room temperature for 3.5 h and partitioned between 800 mL of dichloromethane and 600 mL of water. The organic layer was dried (MgS04) and concentrated in vacuo. The crude oil was purified by column chromatography over 80 g of silica gel (eluted with ethyl acetate-hexanes, 1:3) to afford 2.76 g ( 68 %) of benzyl ether 336 as a yellow oil: [a]D +37.7° (CHCI3); IR (neat) 1474,1452 cnrr1; 1H NMR (CDCI3, 250 MHz) 81.93-

2.08 (m, 1H, H4), 2.12-2.24 (m, 1H, H4), 2.93-3.34 (m, 2H, CH 2 CS), 3.36 (s, 3H, OCH3), 3.57

(dd, J = 10.1, 4.2 Hz, 1H, CH20), 3.68 (dd, J = 10.1, 4.0 Hz, 1H, CH20), 4.14-4.22 (m, 1H,

NCH), 4.51 (s, 2H, CH2 Ph), 4.91 (dd, J= 10.2, 1.0 Hz, 1H, NCH20), 5.47 (d, J= 10.2 Hz, 1H,

NCH20), 7.19-7.38 (m, 5H, ArH); 13C NMR (CDCI3, 62.9 MHz) 5 23.6 (t), 44.5 (t), 57.1 (q), 63.8 186 (d), 69.8 (t). 73.3 (t), 76.2 (t), 127.6 (d), 127.8 (d), 128.4 (d), 137.5 (s), 205.4 (s); exact mass calcd. for C i 4 Hig N 02S m/e 265.1138, found m/e 265.1128.

>X.*0^ N

MeO

3 3 7

(S)-(-f)-[N-(Methoxymethyl)-5,-(Benzyloxymethyl)-2,-pyrrolidinylidene]-

6-hepten-2-one (337). A solution of 0.398 g (1.5 mmol) of thiolactam 336 and 0.401 g

(2.1 mmol) of bromoketone 328 in 1.4 mL of chloroform was stirred at room temperature for 3 h.

The mixture was diluted with 7.2 mL of chloroform and 0.598 g (2.3 mmol) of triphenylphosphine was added, followed by 0.455 g (4.5 mmol) of triethylamine. The mixture was heated at 50°C for 14 h, cooled, diluted with 30 mL of dichloromethane and washed with 30 mL of 1 M aqueous sodium dihydrogenphosphate. The aqueous wash was extracted with three

30-mL portions of dichloromethane. The combined organic extracts were dried (MgS 0 4 ) and concentrated in vacuo. The residue was purified by column chromatography over 20 g of silica gel (eluted with acetone-hexanes, 1:5) to afford 0.351 g ( 68 %) of vinylogous amide 337 as a pale yellow oil: [a]D +71.3° (CHCI3); IR (neat) 1701,1641 cnrr1; 1H NMR (CDCI3, 200 MHz) 8

1.69 (m, 2H, H4), 1.75-1.85 (m, 1H, H4-), 2.00-2.10 (m, 3H, H4- and CH 2C=), 2.33 (m, 2H, H3),

3.04-3.36 (m, 2H, H3-), 3.28 (s, 3H, OCH3), 3.48 (m, 2H, CH 20), 3.81-3.89 (m, 1H, NCH), 4.49

(s, 2H, PhCH2), 4.64 (d, J= 10.4 Hz, 1H, NCH20), 4.69 (d, J*= 10.4 Hz, 1H, NCH20), 4.91-5.04

(m, 2H, =CH2), 5.34 (s, 1H, H-)), 5.73-5.87 (m, 1H, CH=), 7.25-7.36 (m, 5H, ArH); 13C NMR

(CDCI3, 62.9 MHz) 8 24.7 (t), 25.0 (t), 31.7 (t), 33.5 (t), 43.0 (t), 55.9 (q), 62.2 (d), 71.9 (t), 73.4

(t), 76.6 (t), 91.8 (d), 114.6 (t), 127.6 (d), 127.8 (d), 128.5 (d), 137.8 (s), 138.7 (d), 165.4 (s),

198.0 (s); exact mass calcd. for C 2iH 2gN03 m/e 343.2147, found m/e 343.2149. 187

^■OMe

3 3 8

(S)-(+)-W-(Methoxymethyl)-5-(hydroxymethyl)-2-pyrrolidlnone (338). To a solution of 2.01 g (10 mmol) of lactam 284 in 20 mL of dry methanol cooled in an ice bath was added 0.757 g (15 mmol) of sodium borohydride in three portions over 30 min. The reaction mixture was stirred at room temperature for 3 h and quenched by addition of 20 mL of water.

Some of the methanol was removed in vacuo and the remaining aqueous phase was saturated with sodium chloride and extracted with five 50-mL portions of dichloromethane. The combined organic extracts were dried (MgS 0 4 ) and concentrated in vacuo. The residual oil was purified by chromatography over 25 g of silica gel (eluted with acetone-hexanes, 1:2) to afford 1.35 g (85%) of 338 as a colorless oil: [a]Q +6.24° (CHCI 3); IR (neat) 3422,1678 cm '1; 1H NMR (CDCI 3 , 250

MHz) 8 1.70-1.83 (m, 1H, C4 (H)), 1.96-2.11 (m, 1H, C 4 (H)), 2.11-2.48 (m, 2H, CH2CO), 3.26 (s,

3H, OCH3 ), 3.41-3.70 (m, 4H, NCH, OH and OCH2), 4.42 (d ,J = 10.4 Hz, 1H, NCH20), 4.84 (d,

J = 10.4 Hz, 1H, NCH20); 13C NMR (CDCI3 , 62.9 MHz) 8 20.52 (t), 30.05 (t), 56.03 (q), 60.32

(d), 64.06 (t), 73.06 (t),176.64 (s); exact mass calcd. for C 7 H13NO3 m/e 159.0895, found m/e

159.0920.

OMe

3 3 9

(S)-(-)-N-(Methoxymethyl)-5-(benzyloxymethyl)-2-pyrrolidinone (339).

To a solution of 1.58 g (9.9 mmol) of alcohol 339 in 60 mL of benzene stirred at room temperature was added successively 6.27 g (49.5 mmol) of benzyl chloride, 30 mL of 50% aqueous sodium hydroxide and 0.347 g (0.99 mmol) of tetrabutylammonium hydrogensulfate. 188 The mixture was vigorously stirred at room temperature for 45 min and partitioned between 600 mL of dichloromethane and 400 mL of water. The organic layer was dried (MgSC> 4 ) and concentrated in vacuo. The crude oil was purified by column chromatography over 80 g of silica gel (eluted with acetone-hexanes, 1:2) to afford 2.20 g (89%) of benzyl ether 339 as a pale yellow oil: [a]D -20.7° (CHCI3); IR (neat) 1700,1454 cm’ 1; 1H NMR (CDCI3, 200 MHz) 81.83-

2.21 (m, 2H, H4), 2.27-2.63 (m, 2H, CH2CO), 3.26 (s, 3H, OCH3), 3.51 (dd, J= 9.8, 4.3 Hz, 1H,

CH2O), 3.59 (dd, J = 9.8, 4.1 Hz, 1H, CH 20), 3.80-3.91 (m, 1H, NCH), 4.50 (s, 2H, CH 2Ph),

4.65 (d, J= 10.5 Hz, 1H, NCH20), 4.78 (d, J= 10.5 Hz, 1H, NCH20), 7.22-7.38 (m, 5H, ArH);

13C NMR (CDCI3, 62.9 MHz) 8 21.9 (t), 30.4 (t), 56.0 (q), 56.9 (d), 71.2 (t), 72.8 (t), 73.3 (t),

127.5 (d), 127.7 (d), 128.4 (d), 137.8 (s), 176.6 (s); exact mass calcd. for C i 3H 16N 0 2 (M+-

CH3 O) m/e 218.1182, found m/e 218.1259, and for C 6H10NO2 (M+-C8 H3O) m/e 128.0712, found m/e 128.0754.

3 4 0

(S)-(+)-5-(Benzyloxymethyl)-2-pyrrolldinone (340). A solution of 3.99 g

(16.0 mmol) of lactam 339 in 32 mL of trifluoroacetic acid and 32 mL of water was stirred at room temperature for 3.25 h and neutralized to pH 7 by addition of saturated aqueous sodium bicarbonate. The mixture was saturated with sodium chloride and extracted with four 150-mL portions of dichloromethane. The combined organic extracts were dried (MgS04) and concentrated in vacuo. To a solution of the residue in 120 mL of methanol was added 120 mL of 5 M aqueous potassium hydroxide and 1.08 g (17.6 mmol) of ethanolamine. The mixture was stirred at room temperature for 4 h and neutralized to pH 7 by addition of 10% aqueous hydrochloric acid. The mixture was saturated with sodium chloride and extracted with five 200- mL portions of dichloromethane. The combined organic extracts were dried (MgS04) and 189 concentrated in vacuo. The crude oil was purified by column chromatography over silica gel

(eluted with acetone-hexanes, 1:1) to afford 2.51 g (76%) of lactam 340 as a pale yellow oil:

[a]D +44.3° (CHCI3); IR (neat) 3238,1696 cm'1; 1H NMR (CDCI3, 300 MHz) 81.67-1.79 (m, 1H,

H4), 2.13-2.24 (m, 1H, H4), 2.27-2.36 (m, 2H, CH2CO), 3.32 (dd, J= 9.2, 8.1 Hz, 1H, CH20),

3.48 (dd, J= 9.2, 3.9 Hz, 1H, CH 20), 3.82-3.90 (m, 1H, NCH), 4.52 (s, 2H, CH 2Ph), 6.21 (br s,

1H, NH), 7.26-7.38 (m, 5H, ArH); 13C NMR (CDCI 3, 75.5 MHz) 8 23.0 (t), 29.5 (t), 53.7 (d), 73.3

(t), 73.8 (t), 127.6 (d), 127.8 (d), 128.5 (d), 137.6 (s), 177.8 (s); exact mass calcd. for

C i2H16N 0 2 (M++1) m/e 206.1182, found m/e206.1194.

BnO.

341

(S)-(+)*5-(Benzyloxymethyl)pyrrolidine-2-thione (341). To a solution of

4.75 g (23.2 mmol) of lactam 340 in 23.5 mL of dichloromethane was added 4.36 g (12.0 mmol) of Lawesson’s reagent .58 The yellow suspension was stirred at room temperature for 4 h and concentrated in vacuo. The semi-solid residue was purified by column chromatography over

100 g of silica gel (eluted with acetone-hexanes, 1:3) to yield 4.38 g ( 86 %) of thiolactam 341 as a pale yellow oil: [a]D +74.4° (CHCI3); IR (neat) 3169,1522 cm'1; 1H NMR (CDCI3, 300 MHz) 8

1.76-1.88 (m, 1H, H4), 2.19-2.31 (m, 1H, H4), 2.82-3.02 (m, 2H, CH 2CS), 3.38 (dd, J = 9.4, 8.3

Hz, 1H, CH20), 3.53 (dd, J= 9.4, 3.9 Hz, 1H, CH 20), 4.07-4.16 (m, 1H, NCH), 4.49 (d, J= 11.9

Hz, 1H, CH2Ph), 4.54 (d, J - 11.9 Hz, 1H, CH 2Ph), 7.26-7.38 (m, 5H, ArH), 8.29 (br s, 1H, NH);

13C NMR (CDCI3 , 62.9 MHz) 8 25.3 (t), 42.7 (t), 61.8 (d), 72.3 (t), 73.4 (t), 127.7 (d), 127.9 (d),

128.5 (d), 137.3 (s), 205.6 (s); exact mass calcd. for C -^H ^N C ^S m/e 221.0874, found m/e

221.0876. 190

3 4 2

(SM-l-HS'-tBenzyloxymethyl^-pyrrolidlnylldenel-e-hepten^-one

(342). A solution of 1.55 g (7.0 mmol) of thiolactam 341 and 1.74 g (9.1 mmol) of bromoketone 328 in 12 mL of chloroform was heated at 65°C for 3.5 h, diluted with 200 mL of dichloromethane and washed with three 100-mL portions of cold saturated aqueous potassium bicarbonate. The combined aqueous washes were extracted with two 100-mL portions of dichloromethane. The combined organic extracts were dried (MgS 0 4 ) and concentrated in vacuo. To a solution of the residue in 26 mL of benzene was added successively 7.344 g (28.0 mmol) of triphenylphosphine, 0.330 g (2.80 mmol) of potassium ferf-butoxide, and 3 mL of tert- butanol. The mixture was heated at reflux for 18 h, diluted with 200 mL of dichloromethane and washed with 200 mL of 1 M aqueous sodium dihyrogenphosphate. The aqueous wash was extracted with three 150-mL portions of dichloromethane. The combined organic extracts were dried (MgS 0 4 ) and concentrated in vacuo. The semi-solid residue was purified by column chromatography over 60 g of silica gel (eluted with ethyl acetate-hexanes, 1:3) to afford 1.44 g

(69%) of vinylogous amide 342 as a pale orange oil: [a]D -90.1° (CHCI3); IR (neat) 3285,1624 cm-1; 1H NMR (CDCI3, 200 MHz) 8 1.59-1.78 (m, 3H, H3 and H4-), 1.97-2.15 (m, 3H, H3 and

H4-). 2.28 (t, J = 7.5 Hz, 2H, CH2CO), 2.57-2.67 (m, 2H, H3-), 3.39 (dd, J= 9.3, 6.8 Hz, 1H,

CH20), 3.47 (dd, J= 9.3,4.8 Hz, 1H, CH20), 3.98-4.11 (m, 1H, NCH), 4.49 (dd, J = 12.1 Hz, 1H,

CH2Ph), 4.56 (d, J= 12.1 Hz, 1H, CH2Ph), 4.92-5.05 (m, 2H, =CH2), 5.07 (s, 1H, =CH), 5.71-

5.92 (m, 1H, CH=), 7.24-7.40 (m, 5H, ArH), 9.90 (m, 1H, NH); 13C NMR (CDCI3, 62.9 MHz) 8

24.1 (t), 25.3 (t), 31.7 (t), 33.5 (t), 41.2 (t), 59.7 (d), 73.0 (t), 73.4 (t), 89.4 (d), 114.6 (t), 127.6

(d), 127.7 (d), 128.4 (d), 137.9 (s), 138.6 (d), 166.5 (s), 198.0 (s); exact mass calcd. for

Ci9H25N 02 m/e 299.1887, found m/e 299.1850. 191

Bn°

H H

343 344 / 366

(aS , 2/7, 5S)-(+)-5-[(Benzyloxy)methyl]-a-4-pentenyl-2-pyrrolidineetha- nol (343) and (aS, 25, 5S)-5-[(Benzyloxy)methyl]-a-4-pentenyl-2-pyrrolidlne- ethanol (344). To a solution of 571 mg (1.91 mmol) of vinylogous amide 342 in 5.7 mL of dry methanol stirred at room temperature was added a trace of methyl orange and 360 mg (5.72 mmol) of sodium cyanoborohydride. A dry solution of hydrochloric acid in methanol was then added dropwise until the reaction color went from yellow to red (pH 3) and was added as needed throughout the next 12 h. The reaction mixture was brought to pH 9 by addition of 1 M aqueous potassium hydroxide, saturated with sodium chloride and extracted with two 30-mL portions of dichloromethane and two 30-mL portions of ethyl acetate. The combined organic extracts were dried (NaaSO,*) and concentrated in vacuo. The orange residue was purified by filtration through a short pad of silica gel (eluted with dichloromethane-methanol, 10:1) to afford 475 mg

(82%) of a 2.5:1 mixture of diastereomers 343 and 344 : 1H NMR (CDCI 3, 250 MHz) signals from major diastereomer 51.25-1.76 (m, 8 H, CH2), 1.81-2.02 (m, 4H, CH 2, OH and NH), 2.06-

2.14 (m, 2H, CH2C=), 3.26-3.62 (m, 4H, CHN and CH 20), 3.72-3.82 (m, 1H, CHO), 4.45-4.53

(m, 2H, CH2Ph), 4.96-5.04 (m, 2H, =CH2), 5.78-5.92 (m, 1H, CH=), 7.28-7.40 (m, 5H, ArH); signals from minor diastereomer 8 3.88-3.98 (m, 1H, CHO).

A fraction of this mixture of diastereomers was chromatographed over activity grade II basic alumina (eluted with dichloromethane-methanol, 200:1 then 150:1 then 100:1 then 50:1) to afford a small amount of the major diastereomer: [

1; 1H NMR (CDCI3 , 250 MHz) 8 1.21-1.71 (m, 8 H,CH2), 1.78-1.98 (m, 2H, CH2), 2.03-2.11 (m,

2H, CH2C=), 2.66 (brs, 2H, OH and NH), 3.30-3.52 (m, 4H, CH20 and NCH), 3.71-3.79 (m, 1H,

CHO), 4.49 (d, J= 12.0 Hz, 1H, PhCH2), 4.55 (d, J= 12.0 Hz, 1H, PhCH2), 4.92-5.03, (m, 2H,

=CH2), 5.74-5.87 (m, 1H, CH=), 7.28-7.37 (m, 5H, ArH); 13C NMR (CDCI3, 75.5 MHz) 8 24.6 (t),

27.8 (t), 32.8 (t), 33.7 (t), 37.4 (t), 42.4 (t), 58.8 (d), 59.0 (d), 71.9 (d), 73.2 (d), 74.2 (d), 114.2 192 (t), 127.5 (d), 127.6 (d), 128.2 (d), 138.2 (s), 138.8 (d); exact mass calcd. for C 19 H29 NO2 m/e

303.2198, found m/e 303.2197.

346 345

(-)-Methyl (2S,5S)-2-[(benzyloxy)methyl]-5-[(2S)-2-hydroxy-6-heptenyl]*1-pyrrolidinecarboxylate (346) and (-)-Methyl (2S,5R)-2-[(benzyloxy)methyl]-5-[(2S)-2-hydroxy-6*heptenyl]-1-pyrrolidinecarboxylate (345). To a solution of 219 mg (0.723 mmol) of alcohols 343 and 345 in 3.5 mL of dry acetone was added 599 mg

(4.34 mmol) of potassium carbonate and 0.22 mL (2.89 mmol) of methyl chloroformate. The mixture was heated at reflux for 15 h, diluted with 20 mL of water and extracted with two 20-mL portions of dichloromethane and two 20-mL portions of ethyl acetate. The combined organic extracts were dried (MgS 0 4 ) and concentrated in vacuo. The residue was purified by column chromatography over 5g of flash silica gel (eluted with ethyl acetate-hexanes, 1:4) to afford 48 mg (18.4%) of carbamate 346 as a pale yellow oil: [a]o -63.3° (CHCI 3); IR (neat) 3425,1694,

1682 cm-1; 1H NMR (DMSO d 6 at 353K, 250 MHz) 5 1.29-1.55 (m, 5H, CH2), 1.73-1.77 (m, 2H,

CH2), 1.82-1.88 (m, 1H, CH2), 1.92-2.06 (m, 4H, CH2), 3.10 (br s, 1H, OH), 3.38-3.52 (m, 2H,

CHN and CH 20), 3.55-3.61 (m, 1H, CH20), 3.58 (s, 3H, OCH 3), 3.87-3.91 (m, 1H, CHN), 3.93-

4.02 (m, 1H, CHO), 4.47 (d, J = 12.2 Hz, 1H, CH2Ph), 4.53 (d, J= 12.2 Hz, 1H, CH2Ph), 4.93-

5.06 (m, 2H, =CH2), 5.75-5.91 (m, 1H, CH=), 7.26-7.40 (m, 5H, ArH); 13C NMR (DMSO d 6 at

373K, 125.8 MHz) 8 24.1 (t), 25.4 (t), 26.7 (t), 32.7 (t), 36.8 (t), 39.8 (t), 51.0 (q), 54.8 (d), 56.2

(d), 67.2 (d), 69.6 (t), 72.0 (t), 113.9 (t), 126.8 (d), 127.7 (d), 138.2 (s), 138.4 (d), 153.6 (s); one aromatic carbon was degenerate; exact mass calcd. for C 2-|H3iN 0 4 m/e 361.2254, found m/e

361.2250.

Further elution afforded 35 mg (13.4%) of a mixture of carbamates 346 and 345 and 96 mg

(37%) of carbamate 345 as a pale yellow oil: [ct]D -15.5° (CHCI3); IR (neat) 3440, 1681,1640 (m, 1H, CH2), 1.94-2.08 (m, 4H, CH2), 2.30 (m, 2H, CH2C=), 3.55-3.63 (m, 4H, CH20 and

CHOH), 3.68 (s, 3H, OCH3), 4.01-4.09 (m, 2H, CHN), 4.52 (s, 2H, PhCH2), 4.92-5.04 (m, 2H,

=CH2), 5.71-5.88 (m, 1H, CH+), 7.25-7.35 (m, 5H, ArH); 13C NMR (CDCI3 at 327K, 62.9 MHz) 5

25.0 (t), 27.4 (t), 30.8 (t), 33.7 (t), 37.7 (t), 43.7 (t), 52.2 (q), 57.0 (d), 58.3 (d), 70.0 (d), 71.6 (t).

73.4 (t), 114.5 (t), 127.6 (d), 127.7 (d), 128.3 (d), 138.5 (s), 138.8 (d), 156.3 (S); exact mass calcd. for C2iH 3 iN 0 4 m/e 361.2254, found m/e 361.2246.

347 348

(-)-Methyl (2S,5/7)-2-[(benzyloxy)methyl]-5-[(2S)-2-hydroxyheptyl]-1- pyrrolldlnecarboxylate (347) and (-)-Methyl (2S,5S)-2-[(benzyloxy)methyl]-5-

[(2S)-2-hydroxyheptyl]-1-pyrrolldinecarboxylate (348). To a solution of 407 mg

(1.13 mmol) of carbamates 345 and 346 in 8 mL of ethanol was added 40 mg of 10% palladium on carbon. The mixture was hydrogenated in a Parr hydrogenator under 40 psi of hydrogen pressure for 6 h. The mixture was filtered and concentrated in vacuo. The residue was purified by column chromatography over 10 g of silica gel (eluted with ethyl acetate-hexanes, 1:2) to afford 384 mg (94%) of a mixture of carbamates 347 and 348 as a colorless oil: IR (neat) 3440,

1681 cm-1; 1H NMR (DMSOd6 at 350K, 300 MHz) 5 0.84-0.89 (m, 3H, CH3), 1.18-1.38 (m, 9H,

CH2), 1.67-1.74 (m, 1H, CH2), 1.78-1.99 (m, 4H, CH2), 3.38-3.44 (m, 2H, CHN), 3.54-3.59 (m,

1H, CH20), 3.57 (s, 3H, OCH3), 3.90-3.99 (m, 3H, CH20 and CHOH), 4.47-4.49 (m, 2H,

CH2Ph), 7.25-7.36 (m, 5H, ArH); 13C NMR (DMSO d6 at 373K, 125.8 MHz) 8 13.2 (q), 21.5 (t),

24.3 (t), 26.4 (t), 28.6 (t), 30.9 (t), 37.3 (t), 42.0 (t), 51.1 (q), 55.5 (d), 57.2 (d), 67.3 (d), 71. 0 (t),

72.0 (t), 126.74 (d), 126.81 (d), 127.6 (d), 138.2 (s), 154.6 (s); Smaller peaks in the 13C NMR 194 spectrum were attributed to the minor isomer; exact mass calcd. for C 21H33NO4 m/e 363.2410, found m/e 363.2415.

s s A X

349 350

S-Methyl O-hydrogen dithiocarbonate, O-ester with methyl (2S, 5R)-2-

[(benzyloxy)methyl]-5-[(2S)-2-hydroxyheptyl]-1-pyrrolldinecarboxylate (349) and 5-Methyl O-hydrogen dithiocarbonate, O-ester with methyl (25, 55)-2-

[(benzylo-xy)methyl]-5-[(25)-2-hydroxyheptyl]-1-pyrrolid!necarboxylate (350).

To a suspension of 66 mg (1.64 mmol) of 60 % sodium hydride in mineral oil in 1.5 mL of tetrahydrofuran was added successively 99 pL (1.64 mmol) of carbon disulfide, 2 mg (0.03 mmol) of imidazole, and a solution of 60 mg (0.164 mmol) of alcohols 347 and 348 in 1 mL of tetrahydrofuran. The mixture was stirred at room temperature for 24 h and 103 pL (1.64 mmol) of iodomethane was added. The mixture was stirred at room temperature for an additional 2 h, diluted with 50 mL of diethyl ether, and washed successively with 25 mL of saturated aqueous ammonium chloride and 25 mL of brine. The combined aqueous washes were extracted with two 25-mL portions of ethyl acetate. The combined organic extracts were dried (MgSC> 4) and concentrated in vacuo. The residue was purified by column chromatography over 5 g of silica gel (eluted with ethyl acetate-hexanes, 1:5) to afford 63 mg (84%) of a mixture of xanthates 349 and 350 as a pale yellow oil: IR (neat) 1699 cm'1; 1H NMR (CDCI3, 250 MHz) signals from major diastereomer 5 0.87 (m, 3H, CH3), 1.30 (m, 6H, CH2), 1.56-1.81 (m, 5H, CH2), 1.92-2.05 (m, 3H,

CH2), 2.53 (s, 3H, CH3), 3.42-3.72 (m, 3H, CH20 and NCH), 3.68 (s, 3H, OCH3), 3.82-3.92 (m,

1H, NCH), 4.53 (S, 2H, PhCH2), 5.68-5.82 (m, 1H, CHO), 7.24-7.35 (m, 5H, ArH); Signals from minor diastereomer 5 2.58 (s, 3H, SCH 3), 4.48 (d, J= 12.0 Hz, 1H, PhCH2); 13c NMR (CDCI3, 195 62.9 MHz) 5 13.9 (q), 18.6 (q), 22.4 (t), 24.6 (t), 27.2 (t), 30.2 (t), 31.6 (t), 34.0 (t), 39.0 (t), 52.2

(q), 55.5 (d), 58.1 (d)r 71.5 (t), 73.2 (t), 82.6 (d), 127.5 (d). 128.3 (d), 138.4 (s), 155.8 (s), 215.6

(s); one aromatic carbon was degenerate; Smaller peaks in the 13C NMR spectrum were attributed to the minor isomer; exact mass calcd. for C 14H18 NO3 (M+-C9 H-|7 0 S) m/e 248.1287, found m/e 248.1281.

B n 0 ^ o \ N BnO.

O' OMe

352

(-)-Methyl (2S, 5fl)-2-[(benzyloxy)methyl]-5-heptyl-1-pyrrolidinecarboxylate (351) and (-)-Methyi (2S, 5S)-2-[(benzyloxy)methyl]-5-heptyl-1-pyrro- lidlnecarboxylate (352). To a solution of 116 mg (0.4 mmol) of tri-n-butyltin hydride in 2 mL of dry toluene stirred at reflux under argon was added dropwise over 10 min a solution of 91 mg

(0.2 mmol) of xanthates 349 and 350 in 2 mL of toluene. The mixture was stirred at reflux for

20 h and concentrated in vacuo. The residue was purified by column chromatography over 10 g of silica gel (eluted with ethyl acetate-hexanes, 1: 8 ) to afford 16 mg (21%) of carbamate 351 as a pale yellow oil: [a]D -32.0° (CHCI3); IR (neat) 1698 cm’1; 1H NMR (DMSO d 6 at 350K, 250

MHz) 5 0.87-0.92 (m, 3H, CH3), 1.29 (br s, 11H, CH2), 1.61-1.67 (m, 2H, CH2), 1.85-2.00 (m,

3H, CH2), 3.38-3.44 (m, 1H, CH 20), 3.55-3.59 (m, 1H, CH 20), 3.58 (s, 3H, OCH3), 3.70-3.73

(m, 1H, CHN), 3.87-3.91 (m, 1H, CHN), 4.44-4.50 (m, 2H, CH 2Ph), 7.26-7.39 (m, 5H, ArH); 13C

NMR (DMSO d6 at 373K, 125.8 MHz) 5 13.3 (q), 21.5 (t). 25.3 (t), 26.6 (t), 28.0 (t), 28.4 (t), 28.4

(t), 30.7 (t), 51.0 (q), 56.2 (d), 57.4 (d), 69.6 (t), 72.0 (t), 126.8 (d), 127.7 (d), 138.2 (s), 153.7

(s); one aromatic carbon was degenerate; exact mass calcd. for C 2 -|H33N0 3 m/e 347.2460, found m/e 347.2441.

Further elution afforded 39 mg (52%) of carbamate 352 as a pale yellow oil: [a]Q -22.2° (CHCI 3);

IR (neat) 1698 cm"1; 1H NMR (CDCI 3, 300 MHz) 5 0.86-0.90 (m, 3H, CH 3), 1.26-1.33 (m, 11H, 196 CH2), 1.62-1.67 {m, 1H, CH2), 1.88-1.99 (m, 4H, CH2), 3.47-3.54 (m, 1H, CH20), 3.63-3.67 (m,

1H, CH20), 3.67 (s, 3H, OCH3), 3.78-3.82 (m, 1H, CHN), 3.98-4.04 (m, 1H, CHN), 4.53 (S. 2H,

CH2Ph), 7.25-7.35 (m, 5H, ArH); 13C NMR (CDCI 3, 62.9 MHz) 8 14.1 (q), 22.6 (t), 26.2 (t), 27.3

(t), 27.9 (t), 29.3 (t), 29.6 (t), 29.6 (t), 31.6 (t), 52.1 (q), 57.9 (d), 58.9 (d). 71.7 (t), 73.2 (t), 127.5

(d), 128.3 (d), 138.5 (s), 156.1 (s); one aromatic carbon was degenerate; exact mass calcd. for

C2 iH 33N 03 m/e 347.2460, found m/e 347.2479.

(3 S, 4aR, 7S)-(-)-7-[(Benzyloxy)methyl]hexahydro-3-(4-pentenyl)-1H-

pyrrolo[ 1 , 2-c][1,3]oxazin-1-one (353). To a solution of 23 mg (0.076 mmol) of amino-

alcohol 343 in 1 mL of benzene was added 25 mg (0.152 mmol) of carbonyldiimidazole. The

mixture was heated at reflux for 24 h and concentrated in vacuo. The residue was purified by

column chromatography over 3 g of silica gel (eluted with hexanes-ethyl acetate, 2:1) to afford

19 mg (76%) of cyclic carbamate 353 as a pale yellow oil: [a]Q -12.4° (CHCI 3); IR (neat) 1694 cm*

1; 1H NMR (CDCI3, 300 MHz) 8 1.29-1.77 (m, 6 H, CH2), 1.84-2.11 (m, 6H, CH2), 3.48-3.58 (m,

1H, CHN), 3.69-3.76 (m, 2H, CH 20), 4.04-4.10 (m, 1H, CHN), 4.19-4.29 (m, 1H, CHO), 4.47 (d,

J o 11.9 Hz, 1H, CH2Ph), 4.51 (d, J= 11.9 Hz, 1H, CH 2 Ph), 4.94-5.04 (m, 2 H, =CH2), 5.72-5.85

(m, 1H, CH=), 7.24-7.35 (m, 5H, ArH); 13C NMR (CDCI3, 75.5 MHz) 8 24.0 (t), 27.3 (t), 30.7 (t),

33.3 (t), 34.1 (t), 35.0 (t), 56.7 (d), 57.4 (d), 69.5 (t), 73.2 (t), 78.3 (d), 114.8 (d), 127.36 (d),

127.42 (d), 128.2 (d), 138.1 (d), 138.4 (s), 152.1 (s); exact mass calcd. for C 2oH27N0 3 m/e

329.1991, found m/e 329.1993.

353 354 / 367

(3S, 4afl, 7S)-(-)-7-[(Benzyloxy)methyl]hexahydro-3-(4-pentenyl)-1 H-

pyrrolo[1, 2-c][1,3]oxazin-1-one (353) and (3S, 4aS, 7S)-(-)-7-[(Benzyloxy)methyl]hexahydro-3-(4-pentenyl)-1H-pyrrolo[1,2-c][1,3]oxazin-1-one (354). A 9

197 solution of 60 mg (0.20 mmol) of a 1:1 mixture of amino-alcohols 343 and 344 and 65 mg (0.40 mmol) of carbonyldiimidazole in 1 mL of benzene was heated at reflux for 24 h, and concentrated in vacuo. The residue was purified by column chromatography over 10 g of silica gel (eluted with ethyl acetate-hexanes, 1:3 then 1:2) to afford 22 mg (34%) of cyclic carbamate

353 as a pale yellow oil. Further elution afforded 24 mg (36%) of cyclic carbamate 354 as a pale yellow oil: [a]D -15.1° (CHCI3); IR (neat) 1694 cm’ 1; 1H NMR (CDCI 3, 300 MHz) 6 1.32-1.87 (m,

6H, CH2), 1.90-2.16 (m, 6 H, CH2), 3.60-3.67 (m, 1H, CHN), 3.67 (dd, J = 9.5, 2.7 Hz, 1H,

CH20), 3.78 (dd, J= 9.5, 4.9 Hz, 1H, CH20), 4.16-4.23 (m, 1H, CHO), 4.35-4.42 (m, 1H, CHN),

4.53 (s, 2 H, CH2Ph), 4.93-5.03 (m, 2H, =CH2), 5.70-5.83 (m, 1H, CH=), 7.24-7.36 (m, 5H, ArH);

13C NMR (CDCI3 , 75.5 MHz) 8 25.0 (t), 26.0 (t), 31.5 (t), 32.8 (t), 33.1 (t), 33.3 (t), 53.4 (d), 58.2

(d), 70.9 (t), 73.3 (t), 76.1 (d), 115.0 (d), 127.4 (d), 127.5 (d), 128.3 (d), 138.0 (d), 138.6 (s),

152.3 (s); exact mass calcd. for C 2qH27N0 3 m/e 329.1991, found m/e 329.1989.

SES^ X 1 —™\ N Of-Bu N Of-Bu

BnO. H< / V H ? BnO.

A 'OMe

358

(2S,5/?)-2-[(Benzyloxy)methylJ-5-[(2/?)-2-[A/-carboxy-2-(trImethylsilyl)- ethanesulfonamldo]-6-heptenyl]-1-pyrrolidinecarboxyllc acid, AMerf-butyl methyl ester (358) and (2S,5S)-2-[(Benzyloxy)methyl]-5-[(2S)-2-[A/-carboxy-2-

(trlmethylsllyl)ethanesulfonamido]-6-heptenyl]-1 -pyrrolldlnecarboxyllc acid, N- tert-butyl methyl ester (359). To a solution of 1.242 g (4.72 mmol) of triphenylphosphine and 0.992 g (3.92 mmol) of amine equivalent 217 in 20 mL of tetrahydrofuran was added a solution of 0.568 g (1.57 mmol) of carbamates 345 and 346 in 27 mL of tetrahydrofuran. The mixture was chilled in an ice bath and 0.719 g (3.92 mmol) of diethylazodicarboxylate was added dropwise over a 5-min period. The orange mixture was stirred at 0°C for 10 min, at room 198 temperature for 16 h, and concentrated in vacuo. The semi-solid residue was purified by column chromatography over 20 g of silica gel (eluted with ethyl acetate-hexanes, 1:5) followed by filtration through a short pad of activity gade II basic alumina (eluted with ethyl acetate-

hexanes, 1:5) to afford 0.737 g (75%) of carbamates 358 and 359 as a pale yellow oil: IR (neat)

1702, 1640 cm*1; 1H NMR (CDCI3 , 300 MHz) signals from major diastereomer 8 0.05 (s, 9H,

Si(CH3)3); 0.98-1.08 (m, 2H, CH 2Si), 1.36-1.48 (m, 2H, CH2), 1.50 (s, 9H, C(CH3)3), 1.61-1.85

(m, 4H, CH2), 1.91-2.12 (m, 6H, CH2), 3.27-3.54 (m, 3H, CH2 S02 and CH 2 0), 3.60-3.65 (m,

1H, CH20), 3.67 (s, 3H, OCH3), 3.82 (m, 1H, CHN), 4.00 (m, 1H, CHN), 4.20 (m, 1H, CHN), 4.52

(s, 2H, PhCH2), 4.93-5.05 (m, 2H, =CH2), 5.70-5.86 (m, 1H, CH=), 7.24-7.36 (m, 5H, PhCH2); signals from minor diastereomer 8 0.07 (s, 9H, Si(CH3)3), 1.54 (s, 9H, C(CH3)3), 3.54 (m, 3H,

OCH3), 4.48 (d, J= 12.0 Hz, 1H, PhCH2); 13C NMR (CDCI3, 62.9 MHz) 8 -2.1 (q), 10.4 (t), 26.2

(t), 27.3 (t), 28.1 (q), 29.9 (t), 32.7 (t), 33.2 (t), 40.9 (t), 51.5 (t), 52.1 (q), 57.2 (d), 57.5 (d),58.0

(d), 71.5 (t), 73.2 (t), 84.0 (s), 114.8 (t), 127.4 (d), 128.3 (d), 138.3 (d), 138.5 (s), 151.7 (s),

155.8 (s); one aromatic carbon was degenerate: Smaller peaks in the 13C NMR spectrum were attributed to the minor isomer; exact mass calcd. for C3i Hs 2N20 7 SSi m/e 624.3267, found m/e

624.3260.

'Of-Bu

(2S,5/l7)-2-[(Benzyloxy)methyl]-5-[(2/?)-2-carboxyamino-6-heptenyl]-1- pyrrolidinecarboxylic acid, AMerf-butyl methyl ester (360) and (2S,5S)-2-

[(Benzyloxy)methyl]-5-[(2S)-2-carboxyamino-6-heptenyl]-1-pyrrolidInecarbo- xylic acid, N-ferf-butyl methyl ester (361). To a solution of 0.624 g (1.0 mmol) of sulfonamides 358 and 359 in 17 mL of tetrahydrofuran stirred at room temperature was added 199 1.5 mL (1.5 mmol) of a 1.0 M solution of tetrabutylammonium fluoride in tetrahydrofuran. The mixture was stirred at room temperature for 2.5 h, diluted with 50 mL of dichloromethane and washed with 40 mL of water. The aqueous wash was extracted with three 40-mL portions of dichloromethane. The combined organic extracts were dried (MgSC> 4) and concentrated in vacuo. The residue was purified by column chromatography over 10 g of silica gel (eluted with ethyl acetate-hexanes, 1:4) to afford 0.425 g (92%) of carbamates 360 and 361 as a colorless oil: IR (neat) 3346,1694,1682 cm*1; 1H NMR (CDCI 3, 250 MHz) signals from major diastereomer

8 1.23-1.58 (m, 4H, CH2), 1.42 (s, 9H, C(CH3)3), 1.67-1.76 (m, 2H, CH 2), 1.93-2.01 (m, 6H,

CH2), 3.36-3.57 (m, 3H, CH20 and CHN), 3.66 (s, 3H, OCH3), 3.86 (m, 1H, CHN), 4.00 (m, 1H,

CHN), 4.50 (s, 2H, PhCH2), 4.91-5.02 (m, 2H, =CH2), 5.68-5.85 (m, 1H, CH=), 7.23-7.36 (m,

5H, ArH); the NH proton was not observed; signals from minor diastereomer 8 3.62 (m, 3H,

OCH3), 4.47 (d, J= 12.0 Hz, 1H, PhCH2); 13C NMR (CDCI3, 62.9 MHz) 8 24.9 (t), 27.4 (t), 28.5

(q), 30.3 (t), 33.5 (t), 34.4 (t), 41.0 (t), 49.0 (d), 52.1 (q), 56.8 (d), 58.0 (d), 71.6 (t), 73.3 (t), 78.8

(s), 114.5 (t), 127.47 (d), 127.49 (d), 128.3 (d), 138.5 (s), 138.6 (d), 156.4 (s), 156.0 (s); Smaller peaks in the 13C NMR spectrum were attributed to the minor isomer; exact mass calcd. for

C26H4 oN2Os m/e 460.2939, found m/e 460.2951.

362 363

Methyl (2S,5/?)-2-[(benzyloxy)methyl]-5*[(2/?)*2-amlno-6-heptenyl]-1- pyrrolidl-necarboxytate (362) and Methyl (2S,5S)-2-[(benzyloxy)methyl]-5-

[(2S)-2-amino-6-hepte-nyl]-1-pyrrolldinecarboxylate (363). To a solution of 0.411 g (0.893 mmol) of carbamates 360 and 361 in 8 mL of dry acetonitrile was added 0.198 g (1.79 mmol) of chlorotrimethylsilane and 0.268 g (1.79 mmol) of dry sodium iodide. The mixture was stirred at room temperature for 1.5 h and concentrated in vacuo. The brown residue was 200 purified by column chromatography over 10 g of silica gel (eluted with dichloromethane-

methanol, 25:1 then 20:1) to afford 0.264 g (82%) of amines 362 and 363 as a pale yellow oil:

IR (neat) 3450,1668 cm'1; 1H NMR (CDCI 3, 250 MHz) signals from major diastereomer 8 1.29-

1.44 (m, 2H, CH2), 1.53-1.73 (m, 2 H, CH2), 1.78-1.87 (m, 2H, CH2), 1.91-2.08 (m, 6 H,CH2),

3.17-3.20 (m, 1H, CHN), 3.31-3.40 (m, 1H, CH20), 3.60-3.69 (m, 1H, CH 20), 3.69 (s, 3H,

OCH3), 3.86-3.94 (m, 1H, CHN), 4.15-4.29 (m, 1H, CHN), 4.45 (S, 2H, CH2Ph), 4.87-4.98 (m,

2H, =CH2), 5.61-5.75 (m, 1H, CH=), 7.23-7.36 (m, 5H, ArH), 7.43 (br s, 2H, NH2); signals from

minor diastereomer 8 3.60 (s, 3H, OCH3), 4.39-4.51 (m, 2H, CH 2Ph), 4.98-5.02 (m, 2H, =CH2),

5.77-5.85 (m, 1H, CH=); 13C NMR (CDCI3 , MHz) 8 24.8 (t), 26.3 (t), 30.3 (t), 32.7 (t), 33.1 (t),

37.4 (t), 50.7 (d), 53.4 (q), 55.3 (d), 58.3 (d), 69.8 (t), 73.3 (t), 115.0 (t), 127.6 (d), 127.7 (d),

128.3 (d), 137.7 (d), 137.9 (s), 157.0 (s); Smaller peaks in the 13C NMR spectrum were

attributed to the minor isomer; exact mass calcd. for C2i H 3sN20 3 (M++1) m/e 361.2491, found

m/e 361.2489.

(3f?,4a/?,7$)-7-[(Benzyloxy)methyl]hexahydro-3'(4-pentenyl)pyrro-

lo[1,2-c]pyrimidin-1(2H)-one (364) and (3S,4aS,7S)-7-[(Benzyloxy)methyl]hexahydro-3-(4-pentenyl)pyrrolo[l,2-c]pyrimidln-1(2H)-one (365). To a solution of 100 mg (0.28 mmol) of amines 362 and 363 in 2.5 mL of dry toluene was added dropwise 278 pL (0.56 mmol) of a 1.0 M solution of trimethylaluminum in hexanes. The mixture was stirred at room temperature for 1 h, at 90°C for 4.5 h, and quenched by addition of 2 mL of 1

M aqueous sodium hydroxide. The mixture was partitioned between 20 mL of dichloromethane and 10 mL of water. The organic layer was washed successively with 10 mL of 1 M aqueous 201 hydrochloric acid, 10 mL of water and 10 mL of saturated aqueous sodium bicarbonate. The combined aqueous washes were extracted with 20 mL of dichloromethane and 20 mL of ethyl acetate. The combined organic extracts were dried (MgSCX*) and concentrated in vacuo. The

residue was purified by column chromatography over 5 g of flash silica gel (eluted with ethyl acetate-hexanes, 3:1 then 4:1) to afford 23 mg (25%) of cyclic urea 364 as a white solid: mp

105-108°C; [a]D -1.44° (CHCI3); IR (CH 2CI2) 3293, 3220, 1650 cm '1; 1H NMR (C 6D6, 300

MHz) 8 1.02-1.51 (m, 10H, CH2), 1.79-1.88 (m, 2H, CH 2C=), 2.88-2.96 (m, 1H, CHN), 2.98-3.06

(m, 1H, CHN), 3.69-3.71 (m, 1H, CH 20), 3.82-3.86 (m, 1H, CH 2O), 4.19-4.23 (m, 1H, CHN),

4.37 (s, 2H, CH2Ph), 4.94-5.03 (m, 2H, =CH2), 5.65-5.77 (m, 2H, CH= and NH), 7.04-7.27 (m,

5H, ArH); 13C NMR (CDCI3, 62.9 MHz) 8 25.0 (t), 27.1 (t), 30.9 (t), 32.5 (t), 33.4 (t), 37.4 (t), 49.8

(d), 52.8 (d), 56.3 (d), 70.6 (t), 73.2 (t), 114.9 (t), 127.4 (d), 127.5 (d), 128.2 (d), 138.2 (d),

138.6 (s), 155.3 (s); exact mass calcd. for C 20H29 N2O2 (M++1) m/e 329.2229, found m/e

329.2242.

Further elution afforded 15 mg (17%) of a mixture of ureas 364 and 365 and 19 mg (21%) of urea 365 as a pale yellow oil: [a]o -17.6° (CHCI 3); IR (neat) 3290, 3216,1651 cm"1; 1H NMR

(C6D6, 300 MHz) 8 0.82-1.18 (m, 4H, CH2), 1.20-1.38 (m, 4H, CH2), 1.53-1.62 (m, 1H, CH2),

1.70-1.80 (m, 1H, CH2), 1.83-1.87 (m, 2H, CH2C=), 2.83-2.89 (m, 1H, CHN), 3.25-3.32 (m, 1H,

CHN), 3.79-3.83 (m, 2H, CH 20), 4.30-4.36 (m, 1H, CHN), 4.38 (s, 2H, CH 2Ph), 4.93-5.02 (m,

2H, =CH2), 5.62-5.76 (m, 1H, CH=), 6.29 (br s, 1H, NH), 7.03-7.27 (m, 5H, ArH); 13C NMR

(CDCI3 , 62.9 MHz) 8 25.4 (t), 26.6 (t), 32.3 (t), 32.9 (t), 33.4 (t), 35.6 (t), 49.7 (d), 53.0 (d), 56.9

(d), 72.0 (t), 73.2 (t), 114.9 (t), 127.3 (d), 127.4 (d), 128.2 (d), 138.2 (d), 138.8 (s), 155.0 (s); exact mass calcd. for C 2qH29 N20 2 (M++1) m/e 329.2229, found m/e 329.2202. LIST OF REFERENCES

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90. Garipati, R. S.; Weinreb, S. M. J. Org. Chem. 1988, 53, 4143.

91. Dhaon, M. K.; Olsen, R. K.; Ramasamy, K. J. Org. Chem. 1982, 4 7 ,1962.

92. Felix, A. M.; Heimer, E. P.; Lambros, T. J.; Tzougraki, C.; Meienhofer, J. J. Org. Chem. 1978, 43, 4194.

93. Silverman, R. B.; Levy, M. A. J. Org. Chem. 1980, 45, 815.

94. Kowalski, C. J.; Haque, M. S.; Reids, K. W. J. Am. Chem. Soc. 1985, 107,1429.

95. Fuerst, A.; Koller, F. Helv. Chim. Acta 1947, 3 0 ,1454.

96. Pawson, B. A.; Cheung, H.-C.; Gurbaxani, S.; Saucy, G. J. Am. Chem. Soc. 1970, 92, 336.

97. Mizuno, A.; Hamada, Y.; Shiori, J. Synthesis, 1980,1007.

98. Roth, M.; Dubs, P.; Goetschi, E.; Eschenmoser, A. Helv. Chim. Acta 1971, 54, 710.

99. (a) Fujimoto, R.; Kishi, Y. Tetrahedron Lett. 1981,22,4197. (b) Hart, D. J.; Tsai, Y.-H. J. Org. Chem. 1982, 47,4403. (c) Petersen, J. S.; Fels, G.; Rapoport, H. J. Am. Chem. Soc. 1984, 106,4539. (d) Hart, D. J.; Hong, W.-P.; Hsu, L.-Y. J. Org. Chem. 1987, 52, 4665.

100. Ireland, R. E.; Brown, F. R., Jr J. Org. Chem. 1980, 4 5 , 1868.

101. Gugelchuk, M. M,; Hart, D. J.; Tsai, Y.-M. J. Org. Chem. 1981, 46,3671.

102. Gompper, R.; Elser, W. Justus Liebigs Ann. Chem. 1969, 725, 64.

103. Ley, S. V.; Lygo, B.; Molines, H. J. Chem. Soc., Perkin Trans. I 1984, 2403.

104. Borsch, R. F.; Bernstein, R. D.; Durst, H. D. J. Am. Chem. Soc. 1971, 93,2897.

105. Stork, G.; Rosen, P.; Goldman, N. L. J. Am. Chem. Soc. 1961, 83,2965.

106. Ketcha, D. M.; Lieurance, B. A. Tetrahedron Lett. 1989, 6833.

107. Aimi, N.; Yamanaka, E.; Endo, J.; Sakai, S.; Haginawa, J. Tetrahedron 1973, 29, 2015.

108. Kursanov, D. N.; Parnes, Z. N.; Loim, N. M. Synthesis, 1974,633.

109. Bachi, M. D.; Breiman, R.; Meshulam, H. J. Org. Chem. 1983, 4 8 ,1439.

110. Levene, P. A. Org. Syn. 1943, Coll. Vol. II, 8 8 .

111. Regitz, M.; Menz, F. Chem. Ber. 1968, 101, 2622.

112. Kongkathip, B.; Sookkhe, R.; KongKathip, N. Chem. Letters 1985,1849. 207 113. Oppolzer, W.; Battig, K.; Hudlicky, T. Tetrahedron 1981,57, 4359.

114. Ochiai, H.; Tamaru, Y.; Tsubaki, K.; Yoshida, Z. J. Org. Chem. 1987, 52, 4418.

115. Fukusawa, A.; Sato, H.; Masamune, T. Tetrahedron Lett. 1987, 28, 4303.

116. Fletcher, H. G. Methods Carbohydr. Chem. 1963, II, 166

117. Freedman, H. H.; Dubois, R. A. Tetrahedron Lett. 1975,3251.

118. (a) Auerbach, J.; Weinreb, S. M. J. Chem. Soc., Chem. Commun. 1974,298. (b) Meyers, A. I.; Durandetta, J. L.; Munavu, R. J. Org. Chem. 1975, 40,2025. (c) Monti, H.; Leandri, G.; Klos-Ringquet, M.; Corriol, C. Synth. Commun. 1983, 13,1021.

119. Olah, G. A.; Husain, A.; Singh, B. P.; Mehrotra, A. K. J. Org. Chem. 1983, 48, 3667.

120. Hanessian, S.; Delorme, D.; Dufresne, Y. Tetrahedron Lett. 1984, 25, 2515. 121. Woodward, R. B. and 48 coworkers J. Am. Chem. Soc. 1981, 103,3210.

122. Muchowski, J. M.; Solas, D. R. J. Org. Chem. 1984, 49,203.

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125. Mehta, G.; Narayana Murthy, A.; Sivakumar Reddy, D.; Veera Reddy, A. J. Am. Chem. Soc. 1986, 108, 3443.

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140. Laforge, F. B.; Green, N.; Gersdorff, W. A. J. Am. Chem. Soc. 1948,70,3707. APPENDIX

209 INTEGRAL ALG-V-199 (200 MHz, CDCI3) MHz, (200 ALG-V-199 H O C2 H — THPO-CH2- = 162

I n 3.0 r

t 3.5 I22X 1.0 .5 I 1

0.0 210 INTEGRAL THPO ALG-l-202 (250 MHz, CDCI3) MHz, (250 ALG-l-202 163 PPM 3.5 Itt, t 1 I't . 25 . 15 . . 0.0 .5 1.0 1.5 2.0 2.5 3.0 1 i | ' i *i *i i ' | i 1

331 1 r

\ —1 —1 —1 —| 1 • —r |— • 1 1 1 |— 1— 1— 1— 1— |— 1— — * 211 INTEGRAL THPO' ALG-l-197-2 (300 MHz, CDCI3) MHz, (300 ALG-l-197-2 6.0 164 5.5 5.0 PPM 3.5 2.5

0.0 212 165 ALG-ll-116 (250 MHz, CDCI3)

T—I—T T

r—| 213 3 .0 .5 0.0 165 ALG-l-205 (62.9 MHz, CDCI3)

±qJ4]u .^ 1..^A jl-u A i ^ u u i t 214 '^ u * r f it * u*i pi“f7r I-*- INTEGRAL T 1 "T THPO' -- 7.0 I 1 I ■ “ 6.5 ALG-ll-32 (200 MHz, CDCI3) MHz, (200 ALG-ll-32 1 " " 6.0 166 5.5 '~r 5.0 I 1

J W \ J \ o t n n ^ to to . 4.0 4.5 1 — 1 — 1 sCOOH — 1 — 1 PPM 3.5 1 ■ I 3,0 1

1 — 1 —j—r 2.5 u 11 1 i 2 . 0 -

0.0 I

215 PPM S 179.215

TJX o

9LS INTEGRAL ALG-V-180 (200 MHz, CDCI3) MHz, (200 ALG-V-180 171 . . 2.5 5.0 5.5 PPM

. A 217 IT 1*3 ■’* tfi Br \ j XI w

O s —K, PhCHjO

171 ALG-ll-61 (62.9 MHz, CDCI3) 218 ALG-V-154 (300 MHz, CDCI3)

j v L

u u

• 11 1 1 * ' ■ 1 1 1 ■ ■ ■ 1 I 1 ,“ r‘

1.5 1.0 .5 0 .0 219 PPM ALG-V-286 (62.9 MHz, CDCI3) MHz, (62.9 ALG-V-286 . ,OCH2Ph O.. 172 OCH2Ph N —f I

V 220 THP0' f T NY NN^ v / ^ N^ ‘0CH2Ph 14 o H

173 ALG-V-157 (250 MHz, DMSO-ds at 373K) 335 221 \ w ^

THPO

173 ALG-V-157 (62.9 MHz, DMSO-d6 at 373K) 222 INTEGRAL . 70 . 6.0 6.5 7.0 7.5 HO L-V7(5 H, DMSO-d MHz, (250 ALG-IV-7 i , , | , i i | 174 i -- i — i-T

at 373K) at 223 ALG-IV-7 (62.9 MHz, DMSO-d6 at 373K)

yU JjU Uy ALG-VI-81 (250 MHz, DMSO-d6 at 373K) 225 c u ^ c o c f3 r .N

THPO ~f)^Y N N ^COCFa 14 O H

1 7 5 ALG-VI-81 (125.7 MHz, DMSO-d6 at 373K)

N if n i1*!****!* 11“^ itr ff^ n /“ *Ttrir<* T"^N VnVi m v i y^vrxrrVVi~*ri w>Vi^~rfr»~W*«

■ » a .i7 3 227 .COCF.

COCF3 H0~ f T Y N^ 14 O

176 ALG-V-172 (250 MHz, DMSO-d6 at 373K)

i a a ;

7.5 7.0 6.5 6.0 5.5 5.04.5 3.0 2.5 2.0 0.0 PPM 3X1C7W1 tn 1 m !in7J aCD IP <1 T ry ui a CM tvi fM f\l fV 119.040 112.156 116.743 114.460

.COCF-

HO A, N C O C F 3 I

176 ALG-V-172 (125.8 MHz, DMSO-d6 at373K)

m l m)i 229 CKY .COCF,

HO - U r r " ^ COCR 14 O

176 ALG-V-172 (DMSO-d6 at 373K)

i.o

2.5

1— ,— ,— ,— ,— ,— ,— ,— ,— ,— ,— ,— ,— r— .— j- 230 60 55 45 HHM 40 35 :io f

ALG-VI-83 (250 MHz, DMSO-d6 at 373K)

A A. L jIl LAJ V

u i u ;

■’"t 3.0 2.0 1.0 wWwW at373K) 6 .A I I 3 N N H CFa H ,NX ° Y CFa 14 14 o - f r r N- AcO ALG-VI-83 (125.7 MHz, DMSO-d

Hdd 112.190 -112.199 -

’i r r H

7 ALG VI-83 (235.4 MHz, DMSO-d6)

ro co co IMTEMUL 10.0 59 .5 9 ALG-lll-112-1 (200 MHz, CDCI3) MHz, (200 ALG-lll-112-1 .5 8 185 . 6.0 8.0 ■COOH . 55.5 5 .5 6 7.5 PPM .0 5 .5 4 .0 4 .5 3 03.5 3 .0 3 .0 3

0.0 234 1 1 j 1 1 1 i 1 1 1 1 j 1 1 1 1 1 2HTE6RAL ALG-IV-128 (200 MHz, CDCI3) MHz, (200 ALG-IV-128 7.0

6.5 186 COOEt t—j 6.0 1 1 I .5 5 1 1 J I—J 0 4.5 4 .0 5 \ I 1 T 'T I I J U I r 1 I 0 3.5 3 .0 4 j 1

1 ■ r 1 I PPM 1 .0 3 r i -r—j 5 2.0 2 .5 2 1

1 i— 1 —|—' — — v J jv

< — | - T

0.0 235 Br~ \ V - COOEt Br—'

186 ALG-1V-128 (62.9 MHz, CDCI3)

w«JL« CO o> ZHTECfUL ALG-IV-163 (200 MHz, CDCI3) MHz, (200 ALG-IV-163 BrA 182 COOEt E O O -C V 1 1 1 1 1 1 1 1 1 1 -I 0 2. . . 10 5 0.0 0 .5 1.0 1.5 2.0 .5 2 .0 3

\ 1 1 1 ' ■ ~ ■ 1 ' 1 1 1 1 1 1 —1 ' ' 1 1 1 1 1 1 ''1 ■ ■ ■ i~i 237 COOEt rS Ph. .NH HN. .Ph

187 ALG-lll-65 (250 MHz, CDCI3)

- r - T - r ■' I r —r-1

2.5 2.0 1.5 1.0 .5 0.0 238 174.205 ALG-lll-65 (62.9 MHz, CDCI3) MHz, (62.9 ALG-lll-65 phv ^ NH HN^^Ph HN^^Ph NH ^ phv 187 COOEt in m w ocrt cn - t i

n ^ o in OO 0 * o o V

60.506 co co ro COOEt rS Phv ^ NY Nv ^ Ph

o 188 ALG-lll-78 (300 MHz, CDCI3)

* impurity

/ A

T — I -| * f I— I— I— |— I— I— I— I— |— r - n r -T-' 3.0 2.5 2.0 1.5 1.0 .5 0.0 ro o COOEt

r S PhV > N\ y ' N\ / Ph To 188 ALG-lll-78 (62.9 MHz, CDCI3) 241 INTE6AAL ALG-lll-106-1 (200 MHz, CDCIg)MHz, (200 ALG-lll-106-1 . 5.5 6.5 189 COOEt ,NH 5.0 4.5 PPM 3.5 2.5

2.0 242 243 o COOEt T r S 189

w t j z t ALG-lll-106-1 (62.9 MHz, CDCI3) • ^ ■< • INTEGRAL U J 7,5 ALG-IV-15 (200 MHz, CDCI3) MHz, (200 ALG-IV-15 i ■ i ■ 7.0 ) K 6.S 190 * T COOEt s i 1 i 0 5. 0 4.5 4 .0 5 .5 5 .0 6 \ 1 1 1 *i‘ 1 *i | 1 1 1 i s u UJ / 1 1 1 >■ 1 11 r | ■■■| 1 '* 1 A 0 3.5 3 .0 4 "I Jl_A_ 1

PPM 1

1 .0 3 I i'» I 5 2. 1.5 .0 2 .5 2 1

1 ■» I 1 » U 1

1 » . V . . 0 fO .0 0 ' .5 1.0 , , , | | - | | , , , t — | ■ 1 t I t [■ T I1 | —|

COOEt fS PhN /_+T N^ NH I SMa

191 ALG-lll-149 (200 MHz, CDCI3)

f r f

i I , , , r - p - m - | ' n i l | I I | I I i |"i ■ • • I 1 • ' ' 246 3.0 2.5 2.0 1.5 1.0 .5 0.0 m ir r> tfi0 0 a 1 to 17.335

COOEt

PhVv^_+T NW NH I SMe 191 ALG-lll-149 (62.9 MHz, CDCI3) CH2OH

P ^ NrS ^ N ^ P h

O 199 ALG-IV-82 (300 MHz, CDCI3)

// «v rv

CH^OH *

To 199 ALG-IV-82 (62.9 MHz, CDCI3) 249 Jv__ CHaOTBDMS

PhV / Nv w^ Nv / Ph

200 ALG-IV-85 (300 MHz, CDCI3)

11 | i <—1 1 |—1—1—r-i—|—1—1—1—1—|—r 3.0 '3.5 2.0 1.5 1.0 250 CH,OTBDMS

r S Ph, (^N v ^ , N >sX ,Ph

O 200 ALG-IV-85 (75.5 MHz, CDCI3) 251 C H jO T B D P S

ph> -Nv* .NN .ph T o 201 ALG-IV-150 (250 MHz, CDCI3)

(

// / j

i> . l . _AJl J . J ''- u u

I I I 1 1 " f l ■ I ' i~r~r 1 « » 1 1 1 1 • 2.5 2.0 1.5 1.0 .5 0.0 ro cn ro c ' « EM3±M i (\0 pi 1 Br r 1

CH,OTBDPS

* PhV ^ NV ^ N- ' Ph TO 201 ALG-IV-127 (62.9 MHz, CDCI3) 253 c h 2o t b d p s rS P h ^ N NH T O 202 ALG-VI-89 (300 MHz, CDCI3)

/ // J y J y y a

A ii-ii jl*_/A_/VWus- /‘'-u___ -A— PPM ALG-VI-89 (75.5 MHz, CDCI3) MHz, (75.5 ALG-VI-89 H N ^ N / ^ h P * 202 T h c o

2 s p d b t o 255 203 ALG-IV-118 (200 MHz, CDCI3)

J J l

u w uxaa u

I- '-"'" 1 I r ~1 '

3.0 2.5 2.0 1.5 1.0 .5 0.0 256 BnO 204 ALG-IV-119 (200 MHz, CDCI3)

J 257 205 ALG-IV-126 (200 MHz, CDCI3)

r r r j

P i L

1 | 1 1—1 1 | 1111 1 ‘i 1 | - 1 1 1 1 | ■ ■ ■ 1 I '— r - r —1—j—1—it— 1 — 1— j1—1—1—1—r* 1 1 ■' 1 ■■ ' ‘i • 258 4.0 3.5 3.0 2.5 2.0 1.5 1.0 .5 0.0 PPM H2N ' ^ s v / v '0TBDMS 210 ALG-V-265 (200 MHz. CDCl3)

j La . PPM ALG-IV-185 (62.9 MHz, CDCI3) MHz, (62.9 ALG-IV-185 H,N‘ 210 “OTBDMS in in in v c\. cv

>M*» O 05 10 COOEt

A TBDMSO^xv^NH HN^^s^^OTBDMS

211 ALG-IV-187 (200 MHz, CDCI3) PPM ^ ^N ^^v O S M D B T ALG-IV-149 (62.9 MHz, CDCI3) MHz, (62.9 ALG-IV-149 \ r 211 ^1 ^OTB^s s ^ B T O -^ x s N H COOEt \# J

W W M W n i« » < ¥ W W f 262 INTEGRAL 6.5 3.5 3.0 PPM . 3.0 5.5 8.5 . 4.5 5.0 .0 2 TBDMSO, PPM 3.5 ALG-IV-153 (200 MHz, CDCI3) MHz, (200 ALG-IV-153 212 2.5 COOEt 2.0 A ill. ill. A .OTBDMS JL j J 0.0 cn co COOEt

TBDMSOv ^ ^ > .Nv .Nn / - ^ / OTBDMS n o 212 ALG-IV-153 (62.9 MHz, CDCI3) 264 ^W*,WWM7iPIWWrf,|W7WWr^ COOEt

n o 195 ALG-IV-194 (300 MHz, CDCI3)

V ^ _ J

— i " r — j— — “ «—| —i—i ■i,“ ; —i r - y - T - r - t 1 ' 1 1 1 1 '■1 ' 1 1 7 —1 1 1 1 1 1 1 I 1 1 I r r~r~T 1 1 1 265 7 .0 E .5 6.0 5.5 5.0 4 .5 3 .0 2 .5 2.0 1.5 1.0 .5 0.0 V

COOEt

195 ALG-IV-194 (75.5 MHz, CDCI3)

Oi10 O) r - » ■ ■ ■ ' ■' • INTEGRAL MOMON ALG-IV-186-1 (200 MHz, CDCI3) MHz, (200 ALG-IV-186-1 .0 7 1

1 • __ 1

6.5 1 * 213 * X o COOEt \

1 | . 55 . 4.5 5.0 5.5 6.0 1

1 | 1 »—i " 1

1 i f v s I) K 11

J 1 \J '£ l 4.0 \ki) PPH 3.5 ( u 1

3.0 'f r

i"'1' " i ■ 2.5 1.5 -T~>- .5

"~r l"l~ 0.0 267 COOEt

MOMO. ,OMOM

ALG-IV-186-1 (200 MHz, CDCI3) 268 INTEGRAL 7.0 ALG-IV-186-2 (250 MHz, CDCI3) MHz, (250 ALG-IV-186-2 _r_r_r■ ■ ■ ■ 6.5

* T 214 o COOEt 6.0 1

— I 1 r-j-r - j - —r 5.5 I ' I ' 5.0 > I ■> 4.5 j / L I L —|— — t f 4.0 1 r- — UJU u T PPM 3.5 f I n 3.0 1 I'-1-' 2.5 -T -r -r 2.0 J I I I I w H\ a --- 1.5 ) u 1 --- T “ 1.0 r —I— 5 0.0 .5 1 — 1 — 1 — 1 |— — 1 — 1 —

1 r“ —r 269 O HO^ ALG-IV-186-2 (62.9 MHz, CDCI3) MHz, (62.9 ALG-IV-186-2 ___ Vi PI . 156. ^.N * n T 214 o COOEt .N^ . ___ JDMOM _ V

w 270 COOEt

THPO, •OTHP

215 ALG-IV-197-1 (300 MHz, CDCI3)

L i

6 .56.0 9.5 5.0 4.9 3.9 3 .0 2.5 2.0 ro PPM «r a tr V

COOEt

THPO, •OTHP

215 ALG-IV-197-1 (62.9 MHz, CDCI 3)

\i* m teu .eJsmVui ,».■«*»r 272 COOEt

HO, OTHP

216 ALG-IV-197-2 (300 MHz, CDCI3)

V N

COOEt

* H°n >v / ,N> >Nn^ v .othp n o 216 ALG-IV-197-2 (62.9 MHz, CDCI3)

ro 3 .6 3 .4 3 .2 3 .0 2.8 PPM

COOEt

BOC THPO, SES

218 ALG-IV-198 (300 MHz, CDCI3) 275 7 .0 6 .5 6.0 5 .55 .0 4 .5 4 .0 3 .5 3 .0 2 .5 0.0 PPM COOEt

* BOC thp ° v ^ v ^ Y ^ v A ses o 218 ALG-IV-198 (62.9 MHz, CDCI3) 276 COOEt

BOC HO. SES

219 ALG-IV-254 (300 MHz, CDCI3)

I rs r —I- —f— T ~ r~ T T- T T" T - r~ T “ r~ 4.4 4.2 4.0 3. B 3.6 3.4 3.2 3.0 2.0 PPH r r

s / y

^ l .ij W . A

U U \ k U u U l / J U U

I 1 1 1--- 1--- I--- r ‘ I 1 v p i - r r—T"| ■ i i r i 1 ■ ■ 1 277 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 .5 0.0 PPH COOEt

rS BOCl HO* v ^ n '*s e s

0 219 4 (62.9 MHz, CDCI3)

I J u 278 r INTEGRAL 3.6 I 9.0 —r~ 3.4

3.2 1

PPH

1 3.0 I 7.5 —r~ 2.B . 5.5 7.0 T — 2.6 r~

6.5 6.0 ALG-IV-224 (250 MHz, CDCI3) MHz, (250 ALG-IV-224 PPH 220 COOEt 4.0 3.5 BOC SES 3.0 2.5 2.0 jj J V 1.5 0.0 COOEt

V s'-'' T

220 ALG-IV-224 (62.9 MHz, CDCI3) 280 COOEt

BOC A I SES Yo 222 ALG-IV-274 (300 MHz, CDCI3)

/ / J /

j L Ju l j l A ^ l A II . H i ) u u

l ~r ' ' ’ I 1 1 I r—r 1 ■I ■ ■ ■ ■ 2.5 2.0 1.5 1.0 .5 0 .0 N) CO COOEt

BOC I ^ NL* N yv .N. Y SES O 222 ALG-IV-274 (62.9 MHz. CDCI3)

mJL 282 4.6 4.2 3.64.0 2.6 PPM

COOEt

BOC

SES

239 ALG-IV-230 (300 MHz, CDCI3) J f / U I ✓

7.0 6.S 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 .5 0.0 283 PPH

284 64.720 BOC COOEt 239 r S ALG-IV-230 (62.9 MHz, CDCI3) '°vr/N /V N v/v^ SES

MM 3.6 3 .5 3 .4 3 .3 3 .0 2 .9 PPH

COOEt

AcO. ,OAc

240 ALG-IV-239 (300 MHz, CDCI3)

6 .5 6.0 5 .5 5 .0 4 .54 .0 3 .5 3 .0 2.0 0.0

PPH 285 COOEt

* Ac° \ / V Ns / Ns / \ / OAc T o 2 4 0 ALG-IV-239 (62.9 MHz, CDCI3) 286 OTBDMS OTBDMS

CBZ COaEt CBZ

243 ALG-IV-266 (300 MHz, DMSO-d6 at 348K)

/ i I I

i JUU a X A. u

' I ’ ' i ~" r » 1 I 1 ' 1 ' I 1 ■ I 1 1 1 1 i — i— i— i— i— i | i— i— i— — i i I ' 1 ' ' I 1 1 ' I 1 to 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.0 oo PPM ■vl PPM L-V26(2. H, DMSO-d MHz, (125.8 ALG-IV-266 H |^-p - ^ | ^H- TDS OTBDMS OTBDMS B C0E CBZ 02Et C CBZ 243 6 at 373K) at r» ft 0I ^ ^ IT<0 Y q LJUaJL J a U J iL J MTi m m io T "M ow l0 (TJFl 01 O) Ol ■ L momi iD oom m j f w i f

cn m i f

-L 288 962 L--02(0 H, DMSO-d MHz, (300 ALG-V-40-2 6.5 OH B Czt CBZ COzEt CBZ 6.0 242 . 5.0 5.5 OH

6 at 340K) at PPM 3.5

2.0 289 ALG-V-40-2 (125.8 MHz, DMSO-d MHz, (125.8 ALG-V-40-2 PPH • OH B Cjt CBZ COjEt CBZ n N ^ 242 s ^ | n ‘ OH n b

6 at 373K) at a ic r*.tt «C PI a r a rr,

***** - - r - s cv ic m o in o to m ic cv s - r n uju lu co ic ic co ifl 'J T S I W W ,

n 290 INTEGRAL 7.5 T r ALG-IV-278-1 (250 MHz, DMSO-d MHz, (250 ALG-IV-278-1 ‘ I ' 7.0 1 I I ] I 1 I I I ] I I I1 I 1 T 6.5 “T OTHP B COzEt CBZ CBZ .0 6 r 244 5.5 OTHP r I

u 1 6 I 5.0 at 343K) at r

4.5 291 154.902. \v L-V281 20Mz DMSO-d MHz, (250 ALG-IV-278-1 6 OTHP B Cat CBZ COaEt CBZ 244 OTHP

6 at 343K) at ^ W \ \ \ l f f , t f O t i O V C O l l O » * r D C fjTrf'I “ to ro ro OH OTHP

CBZ COzEt CBZ

245 ALG-V-303 (300 MHz, DMSO-d6 at 333K)

6.0 5.5 5.0 4.0 3.5 2.5 2.0 PPM 293 154.950 T ALG-V-278-2 (62.9 MHz, DMSO-d MHz, (62.9 ALG-V-278-2 OH B Czt CBZ COzEt CBZ 245 OTHP

6 at 343K) at w

i / Y N i CBZ COjEt CBZ

246 ALG-V-304 (300 MHz, DMSO-cJ6 at 338K) 295 7.5 6.0 5.5 3.03.5 2.5 2.0 PPM BOC SES OTHP

n ' ^ ' Y ^ n CBZ COjEt CBZ

246 ALG-V-304 (125.8 MHz, DMSO-d6 at 373K) 2KTEM AL ALG-IV-292 (300 MHz, DMSO-d MHz, (300 ALG-IV-292 06.5 6 .0 7 Ox ^SES BOCx B Czt CBZ COzEt CBZ 247 6.0 OH

.5 S 6 at 343K) at s.o .0 4 PPM .033 .5 .5 2 2.0 1.5

0.0 297 T-rnior«>0[*)rs»

If) 1/] (fl D (/i tfl tn ifliflh-H \ \Y BOC^ ^.SES N OH

CBZ COzEt CBZ 247 ALG-VI-80 (125.8 MHz, DMSO-d 6 at 373K)

I W mJ ro (O oo BOC SES

CBZ CO,Et CBZ

248 ALG-V-42 (250 MHz, DMSO-d6 at 373K)

impurity 299 7.5 6.5 6.0 5.0 4.5 3.5 3.0 2.5 2.0 PPM BOC ,SES

HO >

N ^ S|^ ^ N CBZ CO,Et CBZ

248 ALG-V-42 (125.8 MHz, DMSO-d6 at 373K) 300 BOC SES

CBZ COjEt CBZ

249 ALG-V-55 (250 MHz, DMSO-d6 at 363K)

g.o 6.0 5.0 4.0 3.0 2.0 CO PPM o L--5(2. H, DMSO-d MHz, (125.8 ALG-V-55

171.996 O. SES X BOC. ^ O e M C N B Czt CBZ COzEt CBZ i Y " ' ■ 249

(flUlQCCtf) mrv tvtv tvtv w 6 at 373K) at | i i u L | ) 9 D E l O ) O 1 3 O n n in in trii/> in c/iin * y ' p j x in w n n n n m W BOC. .SES

( }

CBZ COzEt CBZ

251 I ALG-V-47 (300 MHz, DMSO-d6 at 343K) / f

JV A J l /uw_A>4 U U U 225

I—1—*—1—1—I—1 1 ' I ' ' ' ' 1 1 n I r ' 4 I 1 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 PPM 154.B96 J V __ L--7(2. H, DMS0-d MHz, (125.8 ALG-V-47 BOC B Czt CBZ COzEt CBZ SES 251

6 at 373K) at CT> CXI > 7 Jl ( om 1 n tn r i o i o o j n n. n 10 t m co m o o ( * * t 0 ctj t i 01 tn ajt/ijw ajt/ijw

tn tn cn|co|cn

- 5^ 5.55. Ph,,sj COOEt

260 ALG-V-60 (250 MHz, COCI3)

I I

V___I L in

< 1 1 t—1—1— r 1 ' I '' T — [— 1— 1— 1— 1— ] — 1— >— i — 1— -|— r ' ■ | j ,-,-r , ! , ■ 1 I • 1 I ' ‘ ' 'I r 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.0 PPM CO o ALG-V-60 (62.9 MHz, CDCI3) MHz, (62.9 ALG-V-60 167 . 016. Ph. Ph. 260 COOEt * c n -riu © r*» tnkni nr cvr cncr m m i n r n i m m T O l O in tn CTlCO c q i cvi i r cto CD J srs.r •krk

^ «0 ® s u n v u =4 £ nintn tn \/ k>iai 31 O ^ O !-» r*» N

306 COOt-Bu *Br—' > 261 ALG-V-77 (300 MHz, CDCI3)

U 3 5 5

1 1 ■ 1 ■■ ■ ■ ■ r 1 i ' 307 3.0 2.5 2.0 1.5 1.0 .5 0.0 PPM ALG-V-77 (62.9 MHz, CDCI3) MHz, (62.9 ALG-V-77 B> Br—' 261 COOf-Bu

V 308 A X™ COOf-Bu

252 ALG-V-84 (200 MHz, CDCI3)

)

i — — i—r 1 1 1 1 1 ■ r 1 I ,-r • I ' ’ I r 1 1 ' 3.5 3.0 2.5 2.0 1 .5 1.0 .5 0 .0 PPM 309 252 A— COOf-Bu Br“\ ALG-V-84 (62.9 MHz, CDCI3)

Hdd INTEGRAL ALG-V-101 (200 MHz, CDCI3) MHz, (200 ALG-V-101 . 3.5 6.5 262 COOt-Bu 6.0 5.5 5.0 PPM u u 3.0

2.0 311 Ph 's| COOf-Bu Ph.

262 ALG-V-101 (62.9 MHz, CDCI3) 312 Ph. S COC^Bu P h. -N .

HN^ y v .OTBDMS

263 ALG-V-120 (300 MHz, CDCI3)

j l L . JL

' I ’• 1 1 ■ 1 ' ■ ■ i 1 ■ ' ■ 1 ■ 1 ■ 1 1 1 1 1 n 1 r ■ 1 1 ■ 1 • * *f 1 1 "T r r 313 7.5 7.0 6.5 6.0 5.5 s.o 4 .5 4 .0 3 .5 3 .0 2 .5 2.0 1.5 1.0 0.0 PPM PPM h ^ . ^N Ph. ALG-V-89 (62.9 MHz, CDCI3) MHz, (62.9 ALG-V-89 ph. COOf-Bu > .OTBDMS . N H 263 iwyiMtW INTEGRAL ALG-V-169 (250 MHz, DMSO-ds at 373K) at DMSO-ds MHz, (250 ALG-V-169 B ^ — ^ CBZ COOPSu 264 .OTBDMS v / 5.5

4.0 PPM ) / 2.5 53.455

QQaiAlflS C tfl X. IU V , W V , VI

COOJ-Bu

OTBDMS

264 ALG-V-169 (62.9 MHz, DMSO-d 6 at 373K) 316 COOt-Bu

265 ALG-V-173 (250 MHz, DMSO-d6 at 373K)

J i l l / / / / / J

.Me. j JL

n j m —i— I— r I ' ' 1 ■ ■ 1 I 1 1 ' 1 l~1 1 I ' 0 3^5 3.0 2.5 2.0 1.5 1.0 .5 0.0 317 PPM a m r-. ^ cr

W *

COOf-Bu

.N . y v .OH CBZ 265 ALG-V-173 (62.9 MHz, DMSO-d6 at 373K) 318 267 ALG-V-93 (200 MHz, CDCI3)

■ | ■ i < ■ | i i r i - | 1 ‘ ■ ■ I 1 1 ■ 1 I ' 1 1 1 I 1 1 1 ■— 2.5 2.0 1.5 1.0 .5 0.0 01 (0

INTEGRAL 7.5 u ALG-V-97-1 (200 MHz, CDCI3) MHz, (200 ALG-V-97-1 > S M T ^ X >V ' h P •■"I 7.0 ° v I I 1 1 I 6.5 268 H ”T I ' » I I I I I '» * T »' I I T ” I . 5.5 6.0 TMS

u / —I —I I I I ‘l I —I I— I l ‘ I I I I I I I I I I— I— I— — I . 45 . 3.5 4.0 4.5 5.0 u PPM W U J J PPM ALG-V-97-1 (75.5 MHz, CDCI3) MHz, (75.5 ALG-V-97-1 Ph 268 H Ov X_. TMS TMS

J " vnv

**** 322 269 ALG-V-272 (300 MHz, CDCI3)

JL JL U

■ 1' 1—I—f T*-J*1 1—I—T“ 3.5 3.0 2.5 2.0 1.5 1.0 .5 0.0 323 Ph O AY N ‘ TMS I H 269 ALG-V-272 (75.5 MHz, CDCI3) Ph. ^ COOf-Bu

CBZ ^ ^ CBZ 271 ALG-V-185 (250 MHz, DMSO-ds at 373K)

Jf Us. f /

I -W_ 1

■■- [—r , * f~ ■ I ' I I 1

4.0 3.5 3.0 2.5 2.0 1.5 1.0 .5 0.0 325 PPM PPH

S <73.035

S 154.BOB S 151.970

00 U1

IV) U1 bo

- I ^

79. 576. Q.

00 00 68.041 66.901

57.389

V S

9 . 2 5 ?

- 2.606

92G COOf-Bu

n y

272 ALG-V-191 (300 MHz, CDCI3)

A L L.

6.0 5.5 5.0 3.5 3.0 2.5 2.0 o.o 327 PPM 65.619

V ^ n ^ y coo ^ u ses " n A A 272 ALG-V-191 (62.9 MHz, CDCI3) 328 N .^s^COOf-Bu

C na nJ i / v ^SO, TMS

273 ALG-V-188 (300 MHz, CDCI3)

y // y / s j i

A A

\ / u2 u SE m tn j i r,

-i—1—1—1—1—r- 1 r I ’ ■ 1 ' ' i • ' ■ 1 ■ ' I 1 1 T r 1 I ' *1 r 1 1 1 1 co 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.0 ro PPM CO 273 ALG-V-188 (62.9 MHz, CDCI3) N + N*

TMS ***? ” H° D 274 ALG-V-216 (300 MHz, D20)

j k f i A 151.226 ALG-V-216 (62.9 MHz, D MHz, (62.9 ALG-V-216 TMS r c c N N + *N S> H ,SC>2 274 c 1 cr i

0) 332 CBZ

SO- TMS

CBZ

2 7 5 ALG-V-207 (250 MHz, CDCI3)

PPM

6.5 6.0 5.5 4.0 3.5 2.5 3 3 3 PPM 1111

CBZ

SO. TMS

CBZ

275 ALG-V-207 (125.8 MHz, DMSO-d6 at 373K)

Jj^.UJ j | HOD

r ^ N ^ V COOH

i cr ■ H H 276 ALG-V-300 (300 MHz, D20)

l i A . A

i— |— i— i— i— c- j - »■ » i— i— |- I i—i i ] i i i i ] i i— r“ 'T"' j “ i ■ i— i—i—|—r 7.5 7.0 6.5 6.0 5.5 5.0 4.5 ,COOH c o r

276 ALG-V-300 (75.5 MHz, D20) 336 CBZ

CBZ

277 ALG-V-282-2 (500 MHz, DMSO-d6 at 373K)

6.5 5.0 4.5 4.0 3.0 S . 5 2.0 0.0 PPM T) N.

CBZ

QBZ ^ v Y O 277 ALG-V-282-2 (125.8 MHz, DMS0-d 6 at 373K)

1 1

/v \, u t\*U , 338 CBZ

CBZ O 277 ALG-V-282-2 (DMSO-d6 at 373K) JLJ III ia

7.0

PPM T" 339 130 120 110 100 9 0 80 70 40 3 0 20 BlS ALG-VI 7.5 -88 o (0 H, DMSO-d MHz, (500 14 6.5 6.0 6 at 373K) o . 5.07.05.5 4.5 PPM

/ ata 3.0 2.5 1.5 1.0 5

0.0 340 150.653 ALG-VI -88 (125.8 MHz, DMS0-,d MHz, (125.8 14 6 at 373K) at o n n l u I O D D O O T D D I ■» _ C\J ifi!■* Lf^c/){cn|cntcn|cn OOi [*) [*> f*) I*) t*1 [*) ffJ CT>ffJ ff) !7l 31 \n — m r * m m ru cv rvjcv ru m m * r m r QD - r cv ci> _ io nj tE o *'* W

r W # W A n J - V ElOjC ( H 283 ALG-l-235 (200 MHz, CDCI3) 13335

I 1 342 3.0 1.0 .5 0.0 V E t O ^ N ^ O

'OMe 284 ALG-l-89 (200 MHz, CDCI 3)

y u

1 r ■ 1 t ■ 1 ■ 1 1 1 1 1 1 ■ 1 1 1 ■ 1 1 1 2.5 2.0 1.5 1.0 .5 0.0 co ■u 01 0 ^1(D U l a ^1 >'<1 p i 0 0 Ol 1® a 0 0 a ir a! 0 «(P 0 •* cn 0 a IT GD 0 _ N 1C ir 0 CD 1C 0 a 0 r* N r»»*N r*» to tn ir a a

in i/i in in t— c c t~ H- a \ /

EtOpC''H> ^ N > < k „...

284 ALG-i-89 (62.9 MHz, CDCI3)

co 4*. I n t eg r a l ALG-l-298 (250 MHz, CDCI3) MHz, (250 ALG-l-298 S ^ N ^ O t E I z 285 H V B.6 PPM

3.5 345 Et02C

285 ALG-J-190 (62.9 MHz, CDCI3) Hv / ~ ~ V

k OWe 286 ALG-l-301 (200 MHz, CDCI3)

ui_ 206. 321. ALG-l-301 (62.9 MHz, CDCI MHz, (62.9 ALG-l-301 286 OMe 3 )

25.025 co 00 » ■I XKUBfUL 1 | * ALG-l-302 (250 MHz, CDCI MHz, (250 ALG-l-302 0 6.5 6 .0 7 1 » O. HO 1

1 I 87 2 1 k —| > —r-i—1 -“1 —1— 1— 1— *-*“ 1— — i - r 1— ■> | 1— OMe . 55 5.0 5.5 6.0 3 ) I U 1 | , ■ , j. , | . . 40 3.5 4.0 4.5 j I L X X _ C PPM k \ ~r 2.0 r ~ T 1.5 r~I~r 1.0 '—I—r 0.0

349 tfl 207.147 ALG-l-302 (62.9 MHz, CDCI3) MHz, (62.9 ALG-l-302 HO, 287 Is OMe m cr OOl"**

M 350 u'OMe , 288 ALG-ll-121 (250 MHz, CDCI3)

.■A i . L ______j L / AM o n e it » si •* pi:

L. OMe 288 ALG-ll-121 (62.9 MHz, CDCI3) 352 ZHTEWUL ALG-ll-121 (250 MHz, CDCl3) MHz, (250 ALG-ll-121 289 k OMe

X A L 353 TsO.

L OMe 289 ALG-ll-121 (62.9 MHz, CDCI3) 354 XNTECfUL ALG-ll-27 (250 MHz, CDCI3) MHz, (250 ALG-ll-27 1 I 7.0 TBDMSO r 1 I .5 6 297 r T k —J—T 6.0 OMe

.5 5 T 1 r 5,0 JJL 4.5 —1 ■ r 4.0 l ilUbL 1 r | PPM .5 3 1 | '—r 1 | ■ i ■ • | 1 • -i— i - t • 1 1 | 1 • 1 ■ i- « ■ 1 | 1 1 r — ' | ■ 1 1

0 2. 0 15 1.0 1.5 .0 2 .5 2 .0 3 355 TB D M SO ^.,.

OMe 297 ALG-ll-27 (75.5MHz, CDCI 3)

M 01 f~T1 0) INTEGRAL - . .-I 7.0 ALG-l-200 (300 MHz, CDCI3) MHz, (300 ALG-l-200 .SMe ^ « * ^ 7 ^ 0 S M D B T ■I"' •■ ’ 6.5 6.0 298 I' L 'OMe 1 I r r I 1 5.5

i ) ) u u 1)I) D CD CD . . . 3.5 4.0 4.5 5.0 C v — f i PPH l - i. u

5555 357 «■«r 01a tc**

h*J \ tbdm so^^+^SMb

^OMe 298 ALG-l-200 (62.9 MHz, CDCI3)

t» V * in03 INTEGRAL ALG-l-225 (250 MHz, CDCI3) MHz, (250 ALG-l-225 e v ^ v ^ v ^ v MeO 6.0 0 0 3

PPM 3.5

2.5 359 ALG-V-14 (200 MHz, CDCI3) f

L aJ uL u s -n-' ■ '' I"■ 4.0 3.0 2.0 1.0 0.0 o> o o O. J

f-BuO v v v X ’

3 0 2 ALG-V-14 (62.9 MHz, CDCI3) 1 6 3 TBDMSO^^

Of-Bu MeO

303 ALG-V-15-2 (300 MHz, CDCI3)

f f JfS -

A j J v I u u \ AH A A A A AJ A \) i 1 ■ ■ ■ 1 1 -r—r-j-r ■^nr 1 1 I r 1 r 1 I

7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.0 362 PPH o in EOTTEB to o w* (T - 10 9 C D l £ 9 IT O ) 9) ^ LD ID m m -» it n

y \ ( Wl r y

TBDMSO.

Of-Bu MeO 303 ALG-V-15-2 (62.9 MHz, CDCI3) 363

vl f tty*'i ttri T“ Y n** if**^‘r"r>‘‘Lrui‘i-tJ--TrTrlTVT‘t,,W ‘r‘‘—m~ *vL* 11 Vm* TBDMSO^^

304 ALG-IV-177 (300 MHz, CDCI3)

I. r f f —i— r—r—| i r—r - T —t—i—i—t— |—r—i—i i j r i i—»—j—r—i—r ■ i ■ 'j ■ i ■ »—v—i—y-> * i—m —j—r 5 .5 5 .0 4.5 4.0 3.5 3.0 2.5 2.0 PPM

f f f j / // J j

j L l l iaaa i ,iUi Ulii . U \)\) \)\ )\)W U k > \)

i ’ ' T—T—i i i i r 1 “ r I T ~ r I- * 1 r r—r 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 ,5 o.o PPM 364 PPM 199.526 TBDMSO impurity* ALG-IV-177 (62.9 MHz, CDCI3) MHz, (62.9 ALG-IV-177 MeO 304 OMe 1/ x IjjL w to o — o to w 9 ot o 9i to tn v

r! 365 INTEGRAL ALG-l-221 (200 MHz, CDCI3) MHz, (200 ALG-l-221 MeO '.J3T .COOEt . V 7 > 305

CN I > y PPH 2.5 o.o o> 5 0 _ ^COOEt TBDMSO^^

CN MeO' 305 ALG-l-221 (62.9 MHz, COCI3) 367 INTEGRAL . 4.5 7.0 ALG-l-224 (200 MHz, CDCI3) MHz, (200 ALG-l-224 HO > ^ . : ___ rr r ■ 6.5 306

j I » I' 6.0 y

COOEt r — T - r “ 5.5 U 1

1 ‘ " ' I 5.0 j \Akk —r 4.0

PPH 3.5 3.0 u ; A k JL J . c A . . 1.5 3.0

172.467 ALG-l-224 (62.9 MHz, CDCI3) MHz, (62.9 ALG-l-224 HO, MeO 306 CN COOEt ¥

34.7£< COOEt MsO.

_____ >

307 ALG-1-227 (250 MHz, CDCI3)

\ / \ /

—1—1— |— 1— r 1 I r 1 I 1 I 1 1 I ' 2.5 2.0 1.5 1.0 .5 0.0 370

J12. 22 T

CN 307 J MeO ^ H< 7 V . COOEt

TSZZTZT ALG-l-227 (62.9 MHz, CDCI3) INTEGRAL L--4 20Mz CDCI3) MHz, (200 ALG-l-249 COOEt ^ MeO J 308 CN 5.5 PPM 3.5

s.o 372 I\l IM a m

H j V COOEt

\ CN MeO 308 ALG-l-249 (62.9 MHz, CDCI3)

i UJ 01-~J 01 309 ALG-1-258 (250 MHz, CDCI3)

■t" I I I l-J ■ i i ■ i ■ ■ ■ ■ i ■ '-'-■-r-'-

1.5 1.0 .5 0.0 374 309 ALG-l-258 (62.9 MHz, CDCI3) 375 310 ALG-l-255-1 (200 MHz, CDCI3)

u u u u

| 1 ' I 1 ■' 1 I* ’ 1 ' I 1 1 1 1 I i 1 -r-' ■—T 1 3.5 3.0 2.5 2.0 i.S 1.0 .5 0.0 u "J 0> ALG-l-255-1 (62.9 MHz, CDCI MHz, (62.9 ALG-l-255-1 16B .I33 NC MeO HN 310 CN .COOEt 3 ) o 0 1 CO 01 / m

W 377 2MTE&AAL N Me N ^ ^ O S M D B T ALG-ll-140 (250 MHz, CDCI3) MHz, (250 ALG-ll-140 Me ' O 321 J T~ '1 " I 5 2. . . . 0.0 0 .5 1.0 1.5 .0 2 .5 2 1

u 1 V ' . C w W 1 ' ^' 1

1 f I 1

1 ^>- - ——1—r 7—r— - --r |^->|-T 378 TBDMSO Me

MeOJ 321 ALG-ll-140 (62.9 MHz, CDCI3) ¥

-U. 379 CHgPh

tbdmso ^"sT?\s t n/C ^a ^ M0

MeO'J 322 ALG-ll-23-1 (200 MHz, CDCI3)

3.0 2.5 2.0 1.5 1.0 55 0.0 PPM 380 ;sss c r J 5 p ie r 2 S 2 £

\ i ( 1

CHzPh

MeO 322 ALG-ll-23-1 (75.5 MHz, CDCI3) 381 TBDMSO N Me I Me 323 ALG-ll-34 (250 MHz, CDCI3) V

TBDMSO. N Me I Me 323 ALG-ll-34 (62.9 MHz, CDCI3)

CO 1 ■ • ■ ■ - INTEGRAL ALG-ll-46 (200 MHz, CDCI3) MHz, (200 ALG-ll-46 7.0 1

1 ’ ' ■ ’ tO E 6.5 1

325 1

Me ■ 6.0 1 > . k J T . 50 . 4.0 4.5 5.0 5.5 1 ---- 1 ---- 1 ---- 1 ---- 1 |* -- | ---- 1 ---- 1 ---- 1 j 1 ---- 1 ---- 1 ---- 1 p PPM 3.5 i J XNTC6AM. ALG-ll-75 (300 MHz, CDCI3)MHz, (300 ALG-ll-75 r - p - r 7.0 1 326 I 5 6.0 6 .5 6 1

1 l~r A U “T"rr“ .5 5 .0 5 I 1 I .5 4 r r r-r*T 4.0 1 I PPM 5 .5 3 r r ill

I, 385 INTEGRAL ALG-ll-73 (200 MHz, CDCI3)MHz, (200 ALG-ll-73 2H ^ v ^ N2CH 327

. 3.0 4.5 PPM 2.5

A. 386 3 2 8 ALG-ll-145 (300 MHz, CDCI3)

u u

r - p - T 1 r ' I ’ -1 * r 1—j—r 1 [_1 "T \~ 1—j- r

3.0 2.5 2.0 1.5 1.0 0.0 387 INTEGRAL 1 7.0 1 r ALG-ll-111 (200 MHz, CDCI3) MHz, (200 ALG-ll-111 6.5 330 T~T 6.0 I I I I I 5.5 I I'll 5.0 r_T_ 1

. . 3.5 4.0 4.5 1

-Jr J \

n •i »« ►•.i in V PPM *. -T . v .-uT v*-.. 3.0 l \ I ' I ' . a.o a.5 1 I 1.5 r

1.0 - .5

T~T_T 0.0 388 331 ALG-ll-117 (250 MHz, CDCI3)

[}[>X t U

'I * |**'I I I | I "‘f *"f~ l | I "I '* T" I | I l '* » I | I ' 1 I ‘ - r — | — t- 3.0 2.9 2.0 1.5 1.0 .5 0.0 389 3 3 2 ALG-ll-119 (200 MHz, CDCI3)

u u IN T E G fU L ALG-ll-122 (250 MHz, CDCI3) MHz, (250 ALG-ll-122 r * r 1 7.0 o 1 1 1 6,5 333 * 6.0 1

1 p-r —p 5,5 1 1 I 4.5 1 —I— 4.0 r t - PPM 3.0 t ~ t —1 —1 —1 1 > 1 1— ■ 1 ■— 1— 1— 1— 1— — i - ‘ h | — 1 - , 29 . 19 . . 0.0 .9 1.0 1.9 2.0 2.9 3,0 U 1 — ' 1— — ’ 1— — ’ —i >— — 1 - 1 1 1 1— 1 1

—1 1—

1 » ~ r 391 TBDMSO,

MeO 334 ALG-ll-127 (250 MHz, CDCI3)

1 jL j CJC UU

1—j—1—1—r—1—|—1—r- 1 1 [■ ■ 1 l r ’ i M' 1 | 11 I 1—1“ j '—r r h —|—r—1—1—1—|—1 I ' * 1 ' | 7.0 6.5 6.0 S.5 6.0 4.5 4.0 3 .5 3 .0 PPM 392 J MeO 334 ALG-ll-127 (75.5 MHz, CDCl3)

) 393 ALG-ll-129 (200 MHz, CDCI3) 35T7B

2.5 2.0 1.5 1.0 394 335 ALG-tl-129 (62.9 MHz, CDCI 3) 395 INTEGRAL ALG-ll-194 (250 MHz, CDCI3) MHz, (250 ALG-ll-194 ^s N^ ^ ^ ° n B h 336 J V ^OMe 5.5 5.0 \l 1 X L - t l l f i 1 11 U ) i\J \U \il\KJ \) PPM . 2.5 3.5 3.0

iC A 396 H* / ” V BnO,

k OMe 336 ALG-ll-194 (62.9 MHz, CDCI3) 396 BnO.

MeO 337 ALG-VI-84 (300 MHz, CDCI3)

/ j )

J l _iML j J U i i ______a L Ajk. u UlAi U \kk)

I I 1 ' 1 I ' 1 I 1 1 11 i 1 1 1 I V 1 1 | r *i 1 1 I ' l l I r I ■ » » 1 .... I 1 T J I I I I ' 7.5 7.0 6.5 6.0 5.5 5.0 4 .5 4.0 3.5 3.0 1.0 0.0 o PPM CD OPN ALG-ll-188 (62.9 MHz; CDCJ3)MHz; (62.9 ALG-ll-188 « n L*

337 398 1 1 1 f1 1 1 | ZK TtCRA L 0 6.5 6 .0 7 —1 —1 —J r J— 1— 1— 1— 1— |— L--3(5 H, CDCI3) MHz, (250 ALG-l-93 o ^ O H 338 1—1 —1 1 —j 1 j— t— 1 1 1— \— 1— — -1 0 5. 0 4.5 .0 6 .6 5 .0 6 k OMe t — | i 1 j > 1 'i r | i " i * 1 I 0 3.6 3 .0 4 1

1 | PPM 1 j k 3.0 CO CO CO HO,

L OMe 3 3 8 ALG-l-93 (62.9 MHz, CDCI3) h *7 V B n 0 ^ 7 \ N^ 0

k OMe 339 ALG-11-220 (200 MHz, CDCI3)

j j .

A A .i 401 339 ALG-ll-208 (62.9 MHz, CDCI3) 402 I H

340 ALG-ll-237 (300 MHz, CDCI3)

V j L

t ■ j— 1 i* 1 i"i' ■ t —1— j— 1— i— r***i— — 1— r— 1— r 1 J 1 1 ■ t— 1— p - r - y - r I 1 I r 6.5 6.0 5.5 5.0 4.5 4.0 3.5 1.0 .5 0.0 PPH O CO 34 0 ALG-ll-237 (75.5 MHz, CDCI3) Hv / ~ V BnO, S I H 341 ALG-ll-280 (300 MHz, CDCI3)

r r

. / j / /

i l J _J l A. It . u u

I i ' 1 "T ’ ' .~l ' 1 I ' ' ' ' ! ' ' ' I 1 ' 'l~' I -1 ' 3.5 3.0 2.5 2.0 1.5 1.0 .5 0.0 405 V

I H 341 ALG-ll-280 (62.9 MHz, CDCI3) 406 in teg r al BnO 10.0 ALG-ll-246 (200 MHz, CDCI3) MHz, (200 ALG-ll-246 9.5 2 4 3 . 7.0 7.5 6.5 J U UU U UU U l . 4.5 5.5 L J J PPM j . l JLWVA. il 3.5 ) J\ J K \k \J K) 3.0

0.0 7 0 4 3 4 2 ALG-ll-246 (62.9 MHz, CDCI3) 8 0 4 409 3.0 3.5 OH PPM

4.5 343 + 344/366 (2.5:1) ALG-V-240 (250 MHz, CDC!3) OH 6.0 6.5 5.5

EE2 7.5 . . OH Hv / V -H I H 343 ALG-V-240-2 (250 MHz, CDCI3)

I 410 OH

343 ALG-V-240-2 (75.5 MHz, CDCI 3) 411 ALG-IV-53-2 (250 MHz, CDCI3)

2.0 412 BnO^

OMe

3 4 5 ALG-lll-54-3 (62.9 MHz, CDCI3 at 327K) 3 1 4 O^^OMe 346 ALG-V-244-2 (250 MHz, DMSO-d6 at 353K)

J - // , //

JV. a __ j l AJ 351 u U U u sas

r r t— i— i— r - ' I ■ ■ I • 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 PPM OH

Q' OMe 346 ALG-V-244-2 (125.8 MHz, DMSO-d 6 at 373K) OH OH

OMe OMe 347 + 348 ALG-V-245 (300 MHz, DMSO-d6 at 350K)

6.5 6.0 s.s 5.0 4.54.0 3.5 3.02.5 2.0 1.5 0.0 PPM 416 OH OH

BnO

OMe 347 + 348 ALG-V-245 (125.8 MHz, DMSO-d 6 at 373K)

^jtil fl m M yi |i |/ tA i O M e A O M e 349 + 350 ALG-IV-79 (250 MHz, CDCI3)

A'\J [) \k) \) 0U\1 IB ~ I U U iU \)

' I ' T—I—I—T- r^ ' I 6.5 6.0 5.5 5.0 4.5 4.0 3.5 2.5 2.0 1.5 1.0 .5 0.0 418 PPM tta j 10 N o H « r to e r» x f* » Pi - n 1 r s i K ' H ' i C C S ' 5 » r i a E S N S - £ r r r r m r <1 r r r c r M Q e «r v v * C = Z V T / “ - - - - / iW r

SMe O 'S M e BnO

OA ' OMe O ' OMe 349 + 350 ALG-IV-79 (62.9 MHz, CDCI3)

JUk 419 9 6 0 ALG-V-253-1 (250 MHz, DMSO-d MHz, (250 ALG-V-253-1 6.5 OMe ' O 351 6.0

5.5 6 at353K) / / PPM 2.53.5

u u 420 PPM

ro cn oo w S 1 5 3 . 6B 5

S 1 3 8 . 1B7 CL o>

CO"4 CO h* 7 V ,* h — s / \ / N

O '^O M e 352 ALG-V-253-2 (300 MHz, CDCI3) 422 PPM aXf-. c\j-» com 1 CVJK\J ALG-V-253-2 (62.9 MHz, CDCI3) MHz, (62.9 ALG-V-253-2 h * V J O^^OMe 352 h A \/ w W w n n in cd 01 I O ^H* r» wn

^ * 423 t J c 353 ALG-VI-8 6 (300 MHz, CDCI3)

impurity 424 Hv / V * H BnO j*Jc 353 ALG-VI-8 6 (75.5 MHz, CDCI 3)

Jlita 425 BnO " . O s H jO' J 0 ' c 354/367 ALG-VI-87-2 (300 MHz, CDCI3)

♦ impurity

U03 A 31 A 71 A r*) i - O lO O a rv L- j i n ' 1 I " | I—I—I- !" | I "I 1 'T | n r 7.5 7.0 3.0 2.5 2.0 1.5 1.0 o.o 426 354/367 ALG-VI-87-2 (75.5 MHz, CDCI3)

A 427 358 + 359 ALG-IV-8 6 (300 MHz, CDCI3)

jfJr.!/ J/

AAA

»— | - r 1 r 2.5 2.0 1.5 0.0 ro oo O SES^ JIs. i ~\ N N N Of-Bu hn / V H ? _ „ H W \,.* H BnO. BnO- ,0 *

O^^OMe 358 + 359 ALG-IV-8 6 (62.9 MHz, CDCI3) 429 ivJ m JJL l f INTEGRAL +1 H+ O'^'OMe 6.5 ALG-IV-89 (250 MHz, CDCI3) MHz, (250 ALG-IV-89 OJ-Bu 6.0 360 360 . 4.57.55.5 7.0 +361 BnO^,-

5.0 OMe . 2.5 4.0 PPM 3.5 3.0 2.0 1.5 1.0 5

0.0 430 N Of-Bu N Of-Bu H*7V*H = BnO, BnO.

0 OMe 360 +361 ALG-IV-89 (62.9 MHz, CDCI3)

i 431 NH. HJ V - h

C '^ O M e 362 +363 ALG-V-258 (250 MHz, CDCI3)

\k) u uuu

5.5 5.0 3.5 2.5 432 PPM 3 \ >do

NH. V*H ,«*H Bno^7 ^ N^ : ^

O^^OMe OMe 362 + 363 ALG-V-258 (75.5 MHz, CDCI3) 433 I H 364 ALG-lll-125-1 (300 MHz, C6D6)

/ / / / /O il 434 i ! 1 " I—r I —f ’ 6.5 6.0 5.5 5.0 4.5 4.0 3.5 PPM PPM

£22. "X 8 ilH ii

3OJ r“ o t in qog

ro O)

x - z

o> o>

6.47 73.1B6 70.549.

0 ,PR9

D fip. 7fifi D 49,,933

37.442. Illlif. 2 7 ,;04. 25.013

get' 365 ALG-lll-125-2 (300 MHz, C6D6) 436 53.041. ct> m cn cn m cm

in in cn

365 ALG-V-262-2 (62.9 MHz, CCCI3) 437