Synthesis of Ergoline Ethers;

Home , Agroclavine, Elymoclavine, Ergoline, Ergometrinine, Lysergic acid, Lysergol

by Brian L. Thompson

A dissertation submitted to the faculty of The University of Utah in partial fulfillment of the requirements for the degree of

Doctor of Philosophy

Department of Medicinal Chemistry The University of Utah December 1978 THE UNIVERSITY OF UTAH GRADUATE SCHOOL

SUPERVISORY COMMITTEE APPROVAL

of a dissertation submitted by

Brian L. Thompson

I have read this dissertation and have found it to be of satisfactory quality for a doctoral degree. ') c ( J Dare/ ,:) H. Richard Shough

Chairman. Supervisor\ Commitlee

I have read this dissertation and have I' / d it to be of satisfactory quality for a doctoral degree. /0-/;·,7[/ e:;/tt1/l-��- ,r/(�·

Dare Robert C. �1ason

Member. Supervisory Commitree

I have read this dissertation and have found it to be of satisfactory quality for a doctoral degree. -!�-71{ Oak fD William K. Nichols

\;lember. SupervisorY Commitrce

Member. Supervisory Commitree

� t� _Cl, have read this dissertation and have found it t. e of satisfactory quality _

· ..·· - --:- .. ··-- -· : , doctoral degree. ' 1 --- (L �-41Cc'((ii� Ie 113/'7\ tb�::�, Dare I Ie . Oa 1 e Pou 1 ter

Member. Supervisory Committee THE U\,[VERSITY' OF UTAH GRADUATE SCHOOL

FINAL READI0iG APPROVAL

To the Graduate Council of The University of Utah:

an [have read the thesis of Sri L. Thompson in its fiml form and have found that (I) its format. citations. and bibliographic style are consistent and acceptable; (2) its illustrative materials including figures. tables. and charts are in place: and (3) the final manuscript is satisfactory to the Supervisory Committee and is ready for submission to the Graduate School,

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James L. Clayton . t1 Ilt:

The photoaddition of water to the ergot clavine alkaloid, lyser gene, has been reported by Shough and Taylor. The product of this reaction, 10-hydroxyagroclavine, was found to rearrange in aqueous acid to give the 8-hydroxy derivative setoclavine. A second photo addition of water then gave the 8,10-dihydroxy derivative, lumi setoclavine. It was suggested that this same series of reactions could be run in alcohols to give the analogous 10-alkoxy, 8-alkoxy, and 8,10-dia1koxy ergoline ethers. Ergolene ethers of this type and c1avine alkaloids, in general, are of current interest due to the recently described prolactin inhibition of certain c1avine alkaloids and the potent a-adrenergic b10ckage of the ergo1ine ether, nicer goline. The main objective of this study, then, was to attempt the synthesis of ergolene ethers by various methods including the photo addition of alcohols to lysergene. It was also anticipated that cer tain of these ergolene ethers could be useful as intermediates in a new synthesis of lysergic acid amides starting from the clavine alka lid elymoc1avine. The photoaddition of methanol to 1ysergene was accomplished to give 10 a-methoxyagroc1av;ne. This photoaddition reaction was not successful in higher alcohols, however. The 10 a-methoxyagroc1avine was, therefore, used to obtain the 8-methoxy, 8-ethoxy, 8-n-propoxy,

8-isopropoxy and 8-~-butoxy derivatives by acid catalyzed equilibration in the appropriate alcohol. An attempt to synthesize the 8,10- dialkoxy derivatives by a second photoaddition of alcohols was, again, unsuccessful. The failure of this second photoreaction seems to indi cate that the photoaddition of alcohols across the 9,10 double bond of ergot alkaloids to form the limi-derivatives is not as general a reac tion as had previously been supposed. Two nonphotochemical methods were also investigated in an attempt to synthesize ergoline ethers. The solvomercuration-demercuration procedure of Brown was attempted with lysergene, lysergine, agro clavine, elymoclavine, and lysergol. This procedure was unsuccessful in our hands, however, as the starting materials were recovered unchanged. The oxidation of agroclavine with manganese dioxide in methanol was also attempted. The expected 10-methoxyagroclavine ap peared to be the product along with some lysergene. The yield was poor, however, and the product could not be isolated. When this reac tion was run in i-butanol, lysergene was isolated in about 20 percent yield. Earlier, in this lab, we synthesized the 10 a-methoxy-~8,9- 1ysergaldehyde from elymoc1av;ne. In the present study this aldehyde was reduced with sodium borohydride to form the 10 a-methoxyelymocla vine which was then rearranged in acidic methanol to give the 8-methoxy- 6-methYl-~9,10-8-hydroxymethYlergoline. Also, in this lab, Choong was able to synthesize the lysergic acid methyl ester by a cyanide catalyzed, manganese dioxide oxidation of the 10 a-methOxy-~8,9_lysergaldehyde. A modification of this

v procedure was used in this study to synthesize a series of lysergic and isolysergic acid amides. The cyanide catalyzed, manganese dioxide oxidation was run in the presence of the appropriate amine to give 10 ~-methoxy-~8,9_lysergic acid amide, 10 a-methoxy-~8,9_lysergic acid piperidine amide, and 10 a-methOxY-68,9-lysergic acid L-2-amino-l propanol amide. The 10-methoxy group was then reduced with zinc and acetic acid to give isomeric lysergic acid amides. This represented the first synthesis of lysergic acid amides from the clavine alkaloid elymoclavine.

vi ACKNOWLEDGMENTS

The author would like to thank the University of Utah College of Pharmacy Graduate Program Committee for the financial support which he received. A special expression of deep love and appreciation is due to the author1s wife, Joia, for the hard work and sacrifice which she has endured to help make this dissertation possible. The author is indebted to his parents, Mr. and Mrs. Eugene Wright, for their encouragement, support, financial aid, and profound love and understanding. The author is grateful to Dr. James A. McCloskey and his staff for obtaining mass spectra; to Dr. A. Srinivasan for NMR data; to Jeanne Branson for her assistance and support; and to Dr. H. Richard

Shou~h for his assistance throughout this study. Special thanks are due to the author1s father, Mr. Leland G. Thompson, Dr. and Mrs. Charles Robert Sokol, Mr. and Mrs. Clinton Bond, Mr. and Mrs. Earl D. Thompson, Mr. and Mrs. Charles Richard Sokol, Miss Carol Sokol, and the author1s two dear little children, Brian Robert and Megan Gayle Thompson. No acknowledgment would be complete without an expression of appreciation for our Heavenly Father upon whose eternal laws science is predicated. For science is indeed watching God work. TABLE OF CONTENTS

Page ABSTRACT. . . . iv ACKNOWLEDGMENTS vi; LIST OF TABLES ix LIST OF FIGURES x LIST OF SCHEMES xi CHAPTERS

I. INTRODUCTION

The Ergot Alkaloids 1 Obj ect; ves . 6 II. BACKGROUND ...... 11 Photochemistry of the Ergot Alkaloids 11 Synthesis of 10-Alkoxyergo1ines 19 Structure-Activity Relationships of the Ergot Alkaloids 28 Production of Lysergic Acid Derivatives 32 III. RESULTS AND DISCUSSION ...... 39 Photochemical Synthesis of 8-Methy1ergoline . 39 Nonphotochemical Synthesis of 8-Methy1ergoline Ethers 52 Synthesis of 8-Hydroxymethylergo1ine Ethers ...... 55 Synthesis of Lysergic Acid Amides from Elymoc1avine (55) 57 Summa ry of Resu 1ts ...... 65 IV. EXPERIMENTAL ...... 69 General Procedures ...... 69 Preparation of Starting Material and Manganese Dioxide. 71 Synthesis of Erog1ine Ethers. . . 73 Synthesis of Lysergic Acid ami des 80 REFERENCES . 85 VITA .... 91 LIST OF TABLES

Table Page 1. Ergot Alkaloids in Current Clinical Use...... 2 2. Configuration and Chemical Shift Data for Alkoxy Ergolines 25

3. Prolactin Inhibitory Activity .... 31 4. Proton Magnetic Resonance and Mass Spectral Data for 8- Alkoxy Derivatives ...... 49 LIST OF FIGURES

Figure Page

1. Classification of the Ergot Alkaloids. 3

2. Conformations of l-Alkoxyergolines 26

3. Photoreaction of Lysergene in Alcohols 41 LIST OF SCHEMES

Scheme Page 1 . 12 2. 12

3. 15

4. 16

5. 18

6. .... 19

7 • •.•. 20 8. 21

9. 23

10. 24

11 . 27

12. 34

13. 35

14. 37

15. 38

16. 43

17 ...... 46

18 " 47

19. 54

20. 56

21. 58 Scheme Page 22. 59

23. 61

24. 63

25. 67

xii CHAPTER I

INTRODUCTION

The Ergot Alkaloids Ergot is the name originally given to the sclerotium which de velops on cereals and grasses infected by the parasitic fungus, Clavi ceps Purpurea (Fries) Tulasne. Today "ergot" applies to approximately 30 species of the genus Claviceps and alkaloids which they produce. During the middle ages, consumption of ergot infected rye was respon sible for epidemics of gangrene and convulsions known as liSt. Anthony's fire. 1I1 Today, the toxic effects of ergot are still sometimes seen in grazing cattle which have eaten ergot infected grasses. 2 The medicinal value of ergot was first recorded in Germany in 1582 where it was used by midwives to induce labor. The crude drug was officially introduced into the United States in the early nine teenth century.2 The first crystalline ergot alkaloid was isolated in 1875 and since then the pure natural alkaloids and their semisynthetic derivatives have been shown to possess a wide variety of pharmacological properties. 3 The major exploitable, pharmacological effects of the ergot alkaloids along with some clinically useful alka loids which exhibit these effects are given in Table 1. Besides these effects, the ergot alkaloids also exhibit a complex array of effects on the central nervous system. Among these are vasodilator, hypoten sive and bradycardic effects, stimulation of the vomiting center, and 2 TABLE 1 Ergot Alkaloids in Current Clinical Use

Actions and Effects Use Alkaloid

Uterine Prevention of post- Ergonovine, contraction partum hemorrhage Methylergonovine Vasoconstriction Treatment of migraine Ergotamine, Dihydroergotamine Serotonin Migraine prophylaxis Methysergide antagonism a-Adrenergic Anti-hypertensive and Dihydroergotoxine, blockade treatment of peri ph- Niceragolinea eral vascular disease Prolactin Terminate lactation 2-Bromo-a-ergo- inhibition kryptinea

aCurrently undergoing clinical evaluation. 8,38 most notably, the hallucinogenic effect of certain lysergic acid amides. 4 Certain types of these alkaloids are also currently being investigated for anti-fertility effects,S control of acromegaly,6 and anti-tumor activity.? The basic structural unit of the ergot alkaloids is the tetra cyclic ergoline ring system (Figure 1). The alkaloids can be divided into two major groups on the basis of the oxidation state of C-17. The major representatives of the lysergic acid group are the so-called peptide alkaloids in which R is a cyclic tripeptide, e.g., ergotamine. Members of this group usually occur in epimeric pairs differing only in their orientation of the functional group at C-8. By convention, 3

8 7

N H I ERGOLINE

COR

N H

CLAVINES LYSERGIC ACID DERIVATIVES R=HOROH) (R=OH, NH2' SIMPLE AMINES, OR CYCLIC PEPTIDE.)

FIGURE I. CLASSIFICATION OF THE ERGOT ALKALOIDS 4 derivatives of lysergic acid, in which the carboxylic acid group at C-8 is B, are given names ending in "-ine," e.g., ergotamine, while derivatives of isolysergic acid, in which the carboxylic acid group at 2 C-8 is a, are given names ending in "-inine," e.g., ergotaminine. Only the derivatives of lysergic acid are used clinically since the derivatives of isolysergic acid are much less active. 9 While C-17 of the lysergic acid group of alkaloids is fully oxidized, C-17 of most of the naturally occurring clavine group of alkaloids is either a methyl or hydroxymethyl. Members of this group of alkaloids do possess pharmacological activity although they are not yet exploited clini cally.4 This may soon change, however, as new interest is developing in the recently described anti-lactation and anti-nidation activities of certain of these alkaloids. Until 1960, the only known source of the ergot alkaloids was cer tain species of the genus Claviceps.10 In recent years, however, these alkaloids have also been isolated from a few species of the Peni cilliumll ,12 and Aspergillus13 ,14 fungi. An exciting discovery was made by Hofmann and Tscherter15 in 1960 when they found that ergot alkaloids occur in higher plants. They identified three alkaloids from the seeds of Ipomea violacea and Rivea corymbosa. Many plants have since been screened for the presence of ergot alkaloids, but their occurrence seems to be limited to certain genera in the Convolvulaceae family, mainly Ipomea and Argyreia, and some species of Rivea and Strictocardia. 16 ,17 Recent studies have indicated that at least twenty-one ergot alkaloids occur in at least five genera of Convol vulaceae. 17 5 The commercial production of ergot alkaloids has been a major topic of interest for a number of years. Ergot alkaloids can be pro duced by: (a) isolation from field cultivated ergot, (b) fermenta tion of the ergot fungus, or (c) partial or total chemical synthesis. 9 At present, production by total synthesis is not economically feasible. Therefore, field cultivation along with a combination of fermentation and partial synthesis are the methods in current use. Over 95% of the peptide alkaloids on the market are obtained by extraction of field cultivated ergot. 9 The medicinally important nonpeptide alkaloids, such as ergonovine, are produced by partial synthesis from lysergic acid. The lysergic acid used for this purpose is obtained by fermentation procedures. Successful fermentation procedures were first developed for the simple c1avine alkaloids by Abe. 18 In 1960, Arcamone 19 developed the first practical fermentation procedure for production of lysergic acid a-hydroxyethy1amide by a strain of Clavicaps paspali. The a-hydroxy ethyl amide is easily hydrolyzed to lysergic acid. A second high yield fermentative procedure was developed by Kobe1. 20 The 68,9-1ysergic acid (paspalic acid) was produced by another strain of Claviceps paspa1i and then isomerized to lysergic acid. A problem remains, how ever, in that the fungal strains used to produce lysergic acid and its derivatives are unstable organisms which are difficult to maintain and tend to lose their ability to produce a1ka10ids. 21 ,22 Currently, the only stable strain of the ergot fungus which is easily maintained and has been shown to consistently produce high yields of alkaloids is a c1avine producing strain C1aviceps fusiformis SO 58. 23 Therefore, 6 there has been increasing interest in the simpler clavine alkaloids as potential starting materials for the synthesis of lysergic acid derivatives. The ergot alkaloids continue to generate a considerable amount of interest and research. Two areas of major concern are: (1) structural modifications to narrow their broad spectrum of activities and thereby provide more selective drugs, and (2) investigation of ergoline derivatives for new pharmacological activities. In light of this, the clavine type alkaloids are generating increasing interest both as sources of new and more selective activity and also as alternative starting materials for the synthesis of lysergic acid derivatives.

Objectives It has been shown recently that several ergot alkaloids and their derivatives are capable of blocking pituitary prolactin secretion. 24- 26 As a result of this inhibition, these alkaloids are capable of tempo rarily preventing lactaton,27 blocking impla~tation of the ova,28 and terminating early pregnancy in female rats and mice. 29 Probably the most exciting aspect of this, however, is that these alkaloids have been shown to inhibit the development of prolactin dependent mammary tumors 30 and pituitary tumors 3l in rats and mice. Ergocornine and ergokrpytine induced regression of carcinogen-induced mammary tumors which appear in postreproductive female rats. 32 Although the role of prolactin in human breast cancer is still unclear,33 there have been recent observations that a small but significant percentage of human breast cancers show some prolactin dependence. 34 7 In light of the above findings, it would be of great interest to synthesize a number of novel ergoline derivatives which could at a later date, be investigated for their effect on certain tumors, acromegaly, fertility and other prolactin dependent processes. This could perhaps add to the knowledge of the structure-activity relationships of the ergolines. Some work has been done on the ergoline structure-prolactin inhi bition relationships.35,36 It was found that a complex peptide similar to the side chain of ergocornine could not inhibit prolactin release and that a large group at the 8 position of the ergoline structure was not necessary for proactin inhibiting activity_ It was also found that the clavine alkaloids agroclavine and elymoclavine possess significant anti-prolactin and anti-tumor activity_ It has also been found recently that certain esters of the clavine alkaloid dihydroelymoclavine show good a-adrenergic blocking activity.37 In an effort to enhance this activity a methoxy group was introduced at C-10. This modification did improve the activity of a number of the esters and one is currently in clinical trial under the name nicer goline. 38 These findings along with their generally lower toxicity seems to make the clavine alkaloids, especially those modified with an alkoxy group at C-10, likely candidates for further study and testing. Previous work in this laboratory established that the clavine alkaloid lysergene undergoes photochemical 1 ,4-addition of water to give lO-hydroxyagroclavine. 39 This compound was found to be unstable in aqueous acid and readily rearranged to the 8-hydroxy alkaloid setoclavine. Another photoaddition of water to setoclavine then 8 provided the diol, 8, lO-dihyroxyagroclavine. It was anticipated, therefore, that analogous reactions with lysergene in various alcohols would yield a series of alkaloids of the types: lO-alkoxy-6, 8- dimethyl-~ 8,9-ergolines, 8-alkoxy-6, 8-dimethyl-~ 8,9-ergolines, and 8, lO-dialkoxyergolines. These novel alkaloids could show some interesting pharmacological properties. Other work in this laboratory was concerned with the synthesis of the lysergaldehyde. This alkaloid is postulated to be an important intermediate in the biosynthesis of the ergot alkaloids. 40 It is seen to be the link between the simple clavine alkaloids and the more complex lysergic acid derivatives. It has not been observed in nature and previous attempts to synthesize it have been unsuccessful. 4l ,42 All attempts to synthesize the unsubstituted lysergaldehyde by oxidation of elymoclavine in this laboratory were also unsuccessful. How ever, the lOa-methoxy-~ 8,9-lysergaldehyde was obtained by manganese dioxide oxidation of elymoclavine in methanol. 43 Following a procedure developed by Corey,44 this aldehyde was further converted to the ly sergic acid methyl ester. 45 This represented the first successful attempt to synthesize lysergic acid from the clavine alkaloids in more than trace amounts. It was then anticipated that by using a modifica tion of the Corey procedure, the aldehyde could be converted to various lysergic acid amide derivatives and provide an alternative route to these medicinally important alkaloids. The major advantages of such a route would be the relatively high yields anticipated and the availability of the starting material for the synthesis, elymoclavine, which 9 is easily obtainable in large amounts from the stable and easily maintained strain of Claviceps fusiformus SO 58. As mentioned earlier, all previous attempts to synthesize the unsubstituted lysergaldehyde have been unsuccessful. A number of oxidation procedures were tried in this laboratory, all without success. It later came to our attention that selenium dioxide might be of use in affecting the oxidation of various clavine-alkaloids to the lysergaldehyde. It was, therefore, decided to try this reagent in a further attempt to procure the important lysergaldehyde. The major objectives of this study, therefore, may be summarized as follows: 1. To investigate the usefulness of the photoreaction of lysergene as a method of synthesizing a series of 10- alkoxy, 8-alkoxy, and 8,lO-dialkoxy ergoline ethers. This series of alkaloids should be suitable for contribut- ing to the knowledge of structure activity relationships of the clavine alkaloids in regard to both prolactin in hibition and adrenergic blockade. 2. To study the usefulness of a modified Corey procedure to synthesize lysergic acid ami des starting from the lOa-methoxy-~ 8,9-lysergaldehyde. The attempted synthesis of lysergic acid amide, ergonovine and lysergic acid piperidine amide would be used to determine the general utility of this procedure as an alternative route to lysergic acid amide derivatives. 10 3. To investigate the selenium dioxide oxidation of cla vine alkaloids in a further attempt to synthesize the lysergaldehyde. This would provide an even more direct route for the synthesis of lysergic acid ami des from elymo clavine. The results of these studies should provide important new know ledge on the chemistry of the ergot alkaloids and provide some novel compounds which would be of interest for their pharmacological proper ties. Also, it is felt that information may be gained which will pro vide possible new routes to the production of the medicinally important ergot alkaloids. CHAPTER II

BACKGROUND

Photochemi stry of the Ergot A1 ka 1oi ds The photochemistry of the ergot alkaloids has been studied by several people over the years. These reactions seem to be analagous to the photochemical ionic reactions of cyclohexenes and conjugated dienes (Scheme 1). In the case of both l-methyl cyclochexene (1)46 and cholestadiene (~),47 the reaction is thought to proceed via addition of the protic solvent to a photochemically induced carbonium ion (2). These types of photoaddi ti on reacti ons have been the subject of two revi ews by Krapp48 and Marshall. 49 ,50 Photochemistry of Lysergic Acid Derivatives. It has been known, since their discovery, that the ergot alkaloids are light sensitive.5l It was not until 1955, however, that the first controlled irradiation experiments were reported. Stoll and Schlientz52 found that irradiation, with direct sunlight, of acidic aqueous solutions of lysergic acid derivatives (8~lQ) or isolysergic acid derivatives (8a-lQ) re sulted in the formation of a new series of alkaloids analogous to the dihydroalkaloids (Scheme 2). These new alkaloids, which they called IIlumill alkaloids, were identified as the lO-hydroxy-9,lO-dihydro derivatives. The notation 12

SCHEME I

H3 CH:30H / H+ ,. • c5 hv o® &: 0 + cS I 2 :3 -4 5 0 71% 2% 2 /0

6 ~ CHOLESTADIEN E +

SCHEME 2 OCH3 9 COR COR COR 0/H H2 +.. bN- CH 3 + CH3 b~CH3 hu HO-- H HO b-H lQ II 12 13 I or II was used to denote the configuration at C-10, thus lumi-I denotes the lOa derivative (11) while 1umi-II denotes the 106 deriva

tive (~). The assignment of configuration at C-10 was based upon a comparison of the products yield, order of absorption on alumina and specific optical rotation with the corresponding 9,10-dihydro deriva tives. It was also found that with the lysergic acjd derivatives

ergotamine (8S-lQ, R = C17H20N304), ergometrine (8B-lQ, R = C3H8NO), and lysergic acid diethylamide (8B-lQ, R = C4H9N), a single isomer predominated (>15:1) which was considered to be the lumi-I derivative (11). On the other hand, the isolysergic acid derivative ergotaminine (8a-lQ, R = C17H20N304) yielded slightly more (- 1 :1.4) of the lumi II derivative. In 1957, Hel1berg53 provided additional information on the photo chemistry of these alkaloids by studying different reaction conditions and producing additional lumi derivatives. He found that there was little formation of lumi derivatives in water or solutions of neutral salts. However, reaction was rapid in acidic solutions. The reaction rate was found to increase with acid strength and also in a series of phosphate buffers of increasing acidity. This effect of increasing acidity is similar to that on the rate of the photochemical ionic reactions of cycloalkenes and butadienes mentioned earlier. Hellberg also found that lysergic acid derivatives yielded mainly the lumi-I products while the iso1ysergic acid derivatives with bulky C-17 substi tuents gave similar yields of both products with the lumi-II slightly predominating. With iso1ysergic acid itself, however, the lumi- 14 isolysergic acid-I was the main product and only traces of lumi isolysergic acid-II were observed. The assignment of configuration at C-10 of the limi derivatives by these early investigators was not unequivocal. Recent work by Bernardi 54 has supported these assignments, however. The configura tion at C-10 of the lumi-isolysergamides (l4a and 15a), lumi ergometrinines (14b and 15b), lumi-lysergamide-I (20), and lumi lysergic acid-I (28) was verified by conversion to the appropriate lactones 16 and 17 as summarized in Scheme 3. With the verification of the configuration at C-10 of these four lumi derivatives, it seems likely that the previous assignments of configuration at C-l0 of the other lumi derivatives were also accurate. Bernardi also found that the ratio of the products lumi ergometrinine-I (14b) and lumi-ergometrinine-II (15b), (1 :1.7), was similar to that observed in the earlier studies while the ratio of the products lumi-isolysergamide-I (14a) and lumi-isolysergamide-II (~ was about 5:1. From these ratios and the ratios of the previous lumi derivatives, it appears that the C/D trans product is preferred in all cases except where the starting alkaloid has a large 8a-substituent such as a substituted amide. In 1969, Bernardi 55 showed that methanol also undergoes photo chemical additions to lysergic acid derivatives (Scheme 4). The ratio of products ~ and 24 was 95:5 in the case of lysergic acid (8B-21a) and 65:35 in the case of isolysergamide (8a-21c). The stereochemistry of the methoxy ethers 23 and 24 was verified in an interesting manner. The IR spectra of the lO-methoxydihydro- 15

SCHEME 3

CONHR CONHR CONHR I I I I I I -CH 3 .. O~CH3 --...~ Q- CH 3 HO Q H HO-- H -150 130,R=H 140 J.§l2.. 13 b, R=CH(CH3)CH20H 14b

COOH o ~ I II I irN-CH3 h N- CH3 - ...... f-T'N- CH 3 0-7--fH Ho-HH O-H-H 17 18 16

CONH2

.. )-\-CH 3 HO-HH -20 16

SCHEME 4

COR COR

__CH_3_0_ H__ b- CH3 b~CH3 hU E9 H

~,R=OH 220 21 b, R = OCH3 22b 21c, R= NH2 22c

COR COR

+ h N- CH3 CH30_b~CH3 CH30HH 230 240 23b 24b 23c 24c

isolysergamides {8a-23c and 8Ci-24c{ showed intramolecular hydrogen bonding between the amide and piperidine nitrogen in 8a-23c but not in -1 8a-24c. ( Hydrogen bonding is indicated by a narrow band at 3480 cm and a broad band at 3200 cm-l replacing the usual NH stretching bands at 3510 cm- l and 3400 cm- l ).56 For hydrogen bonding to occur, the amide group must be axial in 8a-23c which then means that 8a-23c must be C/D tran. By exclusion then, must be C/D cis. The IR spectra of the 10-methoxydihydro1ysergamides (8S-23c and 8B-24c) however, showed no hydrogen bonding in either case so no conclusions could be drawn about the configuration at C-10 based on their IR 17 spectra. The configuration of these compounds was verified, however, by epimerization to the corresponding 10-methoxydihydroisolysergamides (Ba-23c and Ba-24c). Photochemistry of Clavine Alkaloids. Also in 1969, Shough and Taylor57 found that the ergot clavine alkaloid lysergene (25) undergoes a photochemical 1,4-addition of water to form 10-hydroxyagroclavine (26a) in about 60% yield (Scheme 5). The 10-hydroxyagroclavine was unstable in aqueous acid and readily rearranged to give setoclavine (27a) and small amounts of isosetoclavine (2Ba). The photoaddition of water to setoclavine yielded the lumi-I and lumi-II derivatives 29a and 30a respectively. Interestingly, when this same reaction was run at pH 4.6, a 30% yield of the 10-hydroxyagroclavine was obtained. The configuration at C-10 was not determined, but only one isomer was isolated. Only traces of a compound believed to be the epimer were occasionally observed by TLC. The assignment of configuration to lumi-setoclavine-I and lumi setoclavine-II was based on relative yields and chromatographic be havior as in the previous work of Stoll and Schlientz. It was this work which provided the basis for the present study in which we attempted to synthesize the series of compounds where R = alkyl. It is also significant to note that, unlike the lumi-lysergic acid derivatives where the 0 ring is completely saturated, the photo products derived from lysergene retain an B,9 double bond. It is this double bond which allows the 10-hydroxy to rearrange to the B-hydroxy compounds and thereby open the way for photoaddition of a second molecule of water across the resulting 9,10 double bond. 18 SCHEME 5

CH3

ROH --~.,. b N-CH 3 h1J RO H

26a t R = H

2Gb t R = Alkyl

hv ROH/H+

270 280 27b 28b

ROH hlJ

CH3 CH3

RO"'o RO"'b • N-CH 3 + ~ N-CH3 RO-- H RO H 29a 30a 29b 30 b 19 Synthesis of lO-A1koxyergolines

Alcohol/H2So 4 Equilibration Reactions. As mentioned earlier, Barbieri was able to produce lO-methoxy lysergic acid derivatives by direct irradiation of lysergic acid in methanol H2S04" He first isolated the lO-methoxy lysergic acid methylester (23b), however, while attempting the esterification of lumi-lysergic acid in methanol/HC1. 58 Besides the expected methyl ester, he also recovered a substance which was shown to be the lO-methy1 ether. It was subsequently found that when a solution of 1umi-1ysergic acid I (~) or the lactone (lZ) in methanol containing 15% (v/v) H2S04 was left overnight, complete esterification and etherification was achieved and the two compounds 23b and 24b were obtained in approximately 95:5 ratio (Scheme 6).

SCHEME 6

COOH

N- CH 3 + -- H CH30H/H

.lli 0 N- CH3 + 0 N- CH3 ~ CH30-HH CH30HH c ~OH/H+ 23b 24b , N-CH 3 o p H 17 20 This exchange of a methoxyl for a hydroxyl group led Barbieri to con clude that both the photoaddition reaction and these equilibration reactions occur via nucleophilic attack on the intermediate carbonium ion (~, Scheme 4) by a thermodynamically controlled addition. The scope of this acid catalyzed equilibration was studied by Bernardi. 59 The 1,6-dimethyl-8S-hydroxymethyl-10a-methoxyergoline

(~) was obtained by LiA1H4 reduction of the l-methyl-10a-methoxydi hydrolysergic acid methyl ester (11) (Scheme 7). Compound ~ was then equilibrated in acidic methanol, ethanol, ~-propanol and iso propanol (Scheme 8). It was first found that a solution of compound

~ in ethanol/H S0 or ~-propanol/H2S04 yielded, after standing at 2 4 room temperature for two hours, the 1O-ethyl ether (]l) and the 1O-~ propylether (34) respectively. The same reaction run in isopropanol, however, gave the cyclic ether (35). The lO-;sopropylether (lL) was finally obtained by treating 11 with isopropanol/H2S04 to give 36, which was then reduced with LiA1H 4.

SCHEME 7

COOCH3

I CH3

31 32 21 SCHEME 8

EfOH/H+

CH20H CH20H n-PrOH/H+ N- b CH 0 CH3 ------~~~ N- 3 CH30-HH n-C3H70-- H 32 34

i - PrOH/H+

COOCH3

l-PrOH/H+ b CH ------~~ N- 3 l-C3H70-- H 36

ILiAIH4 ~N~CH3 C3H70 -HH 37 22 In order to learn more about the mechanism of this reaction, the

10-methoxyether, 32, and the cyclic ether, ~, were equilibrated in methanol, ethanol, ~-propanol, and isopropanol at various temperatures and reaction times. Treatment of either 32 or 35 at 40°C for 48 hours gave, in both cases, the same mixture of products (Scheme 9). Under these conditions, the lOa ethers (1£, ~, 34) were the main products in all three cases with only ~mal1 amounts of the 106 isomers (38, 39, 40) being formed. As the stearic bulk of the alcohol increases, however, the amount of the cyclic ether (35) formed increases relative to the lOa ether. The equilibration reaction was also carried out in

~-propano1 and isopropanol at 25°C (Scheme 10). Here equilibrium was reached after 40 minutes. In ~-propano1 the lOa either (34) is by far the major product, whereas, in isopropanol the cyclic ether (~) is the major product. Bernardi concluded from these results that in alcohol/H S0 solutions, 32 is in equilibrium with a carbonium ion 2 4 which is attacked by the alcohol from the less sterically hindered side to form the lOa ether. This reaction is rapid, reversible, and kinetically controlled. The carbonium ion can also undergo intra molecular attack to form the cyclic ether (35). This reaction is slow and thermodynamically controlled. When the alcohol has a large steric bulk, therefore, the kinetics of the reaction to form the lOa ether be come unfavorable and the intramolecular reaction to form the cyclic ether is preferred. The assignments of configuration at C-10 of these compounds were made by examination of the chemical shift of their piperidino methyl 23 SCHEME 9

f7""\N- CH 3 bHH 35

MeOH/H+ 40°C 48 hr.

CH20H CH20H

0 N- CH3 + 0 N-CH3 + r7-"\-CH3 CH30-HH CH30HH OHH

~ 38 35

85 5 10 EtOHI H+ 40°C 48 hr.

65 4 31 l!.-PrOH/H +

60 3 37 24

SCHEME 10

r7'N-CH 3 OHH 35

.L - PrOH / H+ rT"N- CH 3 25°C bHH 40 min. 35

10: 90

group (N-CH 3) (Table 2). Bernardi noted that the N-CH 3 signals of 11, il, 32, 44 and 46, all of which are known to have the lOa configuration, fall between 2.408 and 2.498. The N-CH 3 signals of 43 and 38, which are known to have the lOS configuration, however, fall at 2.258 and 2.218 respectively. This seemingly simple correlation, though, is slightly complicated by the fact that 42, 45 and 35 which are also known to have the lOS configuration, have N-CH 3 signals at 2.538 to 2.578. Bernardi explained this discrepancy by pointing out that for compounds with the lOB configuration, two conformations are possible, 25

TABLE 2 Configuration and Chemical Shift Data for Alkoxy Ergolines

N-CH 3 Rl

0 N- CH 3 (CDC1 ) Con- Compound Rl R2 3 formati on

31 a CH 30 B COOCH 3 2.46 a 41 a CH 30 a COOCH 3 2.47 a 42 6 CH 30 a COOCH 3 2.57 a 43 B CH 30 6 COOCH 3 2.25 b 32 a CH 30 B CH 20H 2.40 a 44 ex CH 30 ex CH 20H 2.41 a 45 6 CH 30 a CH 20H 2.56 a 38 6 CHeO B CH 20H 2.21 b

35 N-CH 3 2.53 a 0

46 N-CH 3 2.49 a 0

ex 2.43 a 33 C2H5O B CH 20H a BCH 0H 2.44 a 34 !!.-C 3H7O 2 37 ex l.-C 3H7O 6 CH 20H 2.36 a 6ts ,9 56 ex CH 30 CHO 2.56 68,9COOCH 47 a CH 30 3 2.53 D,3,9CH OH 48 a CH 30 2 2.39 26

~ and £ (Figure 2). It is known that when the substituent at C-8 is a, the preferred conformation is ~, whereas, when the C-8 sUbstituent is p, the preferred conformation is b. In the case of 43 and 38, then, the preferred conformation is £; whereas, 42, 45, and 35 prefer conformation a. Bernardi concluded, therefore, that if the configuration at C-8 is known, the configuration at C-10 can be deduced by

FIGURE 2. CONFORMATIONS OF IO-ALKOXYERGOLINES

examining the chemical shift of the piperdino N-CH 3 group. Using this method he assigned the configurations at C-10 of 33, 34, and 39 as being a. These assignments are also consistent with his proposed mechanism for the above reactions which predicts that the lOa ethers would be formed almost exclusively. Solvomercuration-Demercuration. In 1974, Bernardi 60 was able to produce lOa-methoxy-~ 8,9-1ysergic acid methyl ester (47) via the solvomercuration-demercuration procedure developed by Brown (Scheme 11). Mercuric acetate was added to a methanolic solution of lysergic 27 SCHEME II

COOCH3 b~CH3

21b

I) Hg(OAC)2 IMeOH

COOCH3 COOCH3 I I Pt02/H2 CH3 CH .. 3 CH30--b-H CH30--Q-H 41 47 _.-

I LiAIH4

CH20H CH20H H20 /H+ ,. HO~Q CH3 ~ N- CH 3 CH30--b-H 48 49 28 acid methyl ester (£lb) followed by alkaline sodium borohydride. The dihydro derivative (11) had been expected but the 8,9-didehydro com pound (47) was isolated. The structure and configuration at C-10 were confirmed by hydrogenation to the known compound il. It was also found that the clavine alkaloid penniclavine (49) could be easily prepared by reduction of 47 with LiA1H4 to give 10a-methoxyelymo clavine (48) followed by rearrangement in dilute H S0 " There was 2 4 no report of an attempt to apply this reaction to the clavine alka loids.

Structure-Activity Relationships of the Ergot Alkaloids Excellent discussions of the pharmacology and structure activity relationships of the ergot alkaloids can be found in reviews by Stoll and Hofmann,4 Groger,6l and Stadler and Stutz. 62 The classical activities of the ergot alkaloids consist of direct peripheral effects, s~ch as uterine contraction and vasoconstriction, neurohumoral effects, such as serotonin antagonism and adrenergic blockade, and a variety of central nervous effects. 4 Early work on structure-activity correlations was concentrated on these classical effects. It was found, for instance, that hydrogenation of the 9,10 double bond of these alkaloids greatly lowers the peripheral and cen tral nervous effects while enhancing the neurohumoral effects. 4 Other structural modifications of the ergoline nucleus have been shown to make remarkable changes in the activity spectrum of these alkaloids. 4 Recently, great interest has developed in the anti-prolactin 29 effects24 ,25,26 of certain ergot alkaloids and the potent a-adrenergic blockade of nicergoline. 37 Although some structure activity work has been done concerning these effects,35,36,63 more sophisticated studies await better synthetic procedures for certain structural modifications. This recent work has also stimulated renewed interest in the pharma cology of the c1avine alkaloids. Although known to possess a certain amount of central excitatory activity,4 certain clavines have recently been sown h t 0 have re 1a t 1ve· 1y h'19 h an t'1-pro 1ac t'ln ac t"lVl t y a 1so. 26,35 Prolactin Inhibition. The knowledge that ergot alkaloids could inhibit lactation dates back hundreds of years when it was noted that nursing women suffering from gangrenous ergotism also developed aga1actia. 64 A series of studies, beginning in 1954,65,24-26 have firmly established that certain ergot alkaloids inhibit the release of pituitary prolactin. As a direct result of this inhibition of pro- 1actin release, various ergolines have been shown to prevent 1acta tion,27 retard the development of certain hormone-dependent tumors,30-33 interrupt early pregnancy,29 and prevent implantation of the ova 28 in mice. This influence of the ergot alkaloids on pituitary prolactin has been extensively reviewed by Floss, et ~.64 Several groups of investigators, including Meites,66 Nagasawa,67 and Yanai ,68 have shown that ergocornine, ergokryptine, and 2-bromo- a-ergokryptine, induced regression of carcinogen-induced mammary adenocarcinomas in rats and inhibited the growth of spontaneous mammary tumors which appear in the postreproductive phase of life of female rats. This activity was attributed to the inhibition of prolactin release by these alkaloids. Quadri 69 also found that ergocornine 30 induced significant regression of prolactin secreting pituitary tumors in rats. Only a limited amount of information is available on the rela tionships between the structure of the ergot alkaloids and their pro lactin inhibitory activity. Some preliminary work has been done by Floss, et ~,35 in which certain simple ergolines were tested for their prolactin inhibitory activity. The alkaloids which showed acti vity are listed in Table 3. Their activities are given relative to ergocornine = 100. The complete tetracyclic ergoline ring system seems to be required for activity since chanoclav-ine and other open ring compounds were inactive. The complex peptide side chain at the 8 position is not required, however, since elymoclavine was almost equipotent with ergocornine. From this preliminary work, Floss concluded that the clavine alkaloids could exhibit activity equivalent to the peptide alkaloids and that structural. modification of the D ring could have a great effect on activity. It seems reasonable to assume then than the production of 10-alkoxy and 8-alkoxyergolines could be of benefit in studying the prolactin inhibitory activity of the ergot alkaloids. a-Adrenergic Blocking Activity. In 1968, Arcari 37 observed that various esters of dihydroelymoclavine showed vasodilating and a- adrenergic blocking activity_ It was later found that introducing a methoxy group at the lOa position of these esters increased this activity.38 One compound in particular, the 1,6-dimethyl-8S-(5-bromo nicotinoyloxymethyl)-lOa-methoxyergoline, showed a remarkable increase 31

TABLE 3 Prolactin Inhibitory Activity

Relative Compound Activity

Ergocornine 100

Lysergic acid a-hydroxyethylamide 74

Elymoclavine 95

Dihydroelymoclavine 82

Elymoclavine-O-acetate 80 Elymoclavine-17-carbamate 65

Elymoclavine-17-benzoate 65 Elymoclavine pyridinium tosylate 97

8-Piperidinomethyl-~ 8,9-ergoline 83 Elymoclavine-B-D-fructoside 60

Isolysergol 52

Agroclavine 64 8-Acetoxymethylene-~ 9,lO_ergoline 48

8-Aminoergoline 52 Chanoclavine a 32 in activity. Named nicergoline, this compound also facilitates re- covery from different types of brain damage experimentally induced in animals,70 and increases blood flow as well as oxygen uptake in hu mans. 7l Nicergoline is now being tested clinically in Italy and other European countries as an antihypertensive drug. 38 Since the addition of a methoxy group at the 10 position increased the activity of these compounds, it may also potentiate the activity of other ergolines. Therefore, it would be of benefit to investigate ways of introducing alkoxy groups into the D ring of ergolines. Also, preliminary structure activity studies indicate that the presence of an 8,9 double bond reduces the activity of some of these compounds. 72 Synthesis of'ergo line ethers of this type, then, would be of interest to provide more precise structure activity comparisons.

Production of Lysergic Acid Derivatives As mentioned briefly in the introduction, the major source for commercial production of all the medicinally important ergolines, ex cept the peptide alkaloids, is partial synthesis from lysergic acid. 9 The lysergic acid used for this purpose is obtained from fermentation of the ergot fungus. Farmitalia S.A. uses a strain of Claviceps paspali developed by Arcamone 19 to produce lysergic acid a-hydroxy ethyl amide which is then hydrolyzed to lysergic acid. Sandoz, however, uses a different strain of Claviceps paspali, developed by Kobel,20 to produce the 68,9-lysergic acid which is easily isomerized to lysergic acid. Both of these strains, however, are somewhat un stable and difficult to maintain. 2l ,22 It would be desirable to 33 develop a new source of lysergic acid which involved the use of more stable fungal strains. Also, these lysergic acid producing strains are patented and not available to independent investigators. This limits the availability of lysergic acid and is somewhat stifling to independent research. A number of partial syntheses of various lysergic acid 'ami des have been reported. In 1943, Stoll and Hofmann 73 reported the syn thesis of ergonovine (~) from lysergic acid methyl ester (2lb) (Scheme 12). 2lb was heated with hydrazine to form the racemic iso lysergic acid hydrazide (50). This mixture had to be resolved into its optically active components with di-(Q-toluyl)-tartaric acid.

The ~-isolysergic acid hydrazide was then converted to the azide (~) and condensed with L-2-aminopropanol to give ergonovinine. This could be isomerized by alkaline treatment to the desired ergonovine (52). The obvious drawback to this synthesis was the racemization which occurred during the first step. Two, more direct, syntheses of ergonovine have been reported recently (Scheme 13). Sas 74 produced ergonovine (~) and methyler gonovine (54) by condensing L-2-aminopropanol or L-2-aminobutanol with the lysergic acid choloride (53). Milohnoja 75 has also produced 52 and 54 by direct condensation of L-2-aminopropanol or L-2-amino butanol with lysergic acid (2la) in the presence of N,N'-carbonylbis (imadozole) or (CH3SO)20. He also prepared lysergic acid diethyla mide by condensing lysergic acid and Et2NH in the presence of (CF3CO)20 at -25°C. 34 SCHEME 12

CONHNH2 I I .. O~CH3 50 I) d i - ( p - tol uy I ) - tartaric acid

2) BASE

52 35

SCHEME 13

COOCH3 0 0 II II CIC-C-CI ~ N~CH3 ~ q CH2R I 21b H2N-CH I CH 2 0H

I) N,N-Carbonyl bisimidazole

2) CH2R I H2N -CH 52 , R =H I CH20H 54, R = CH3 36

All the above syntheses of lysergic acid derivatives used lyser gic acid as starting material. In 1977, however, Choong 45 reported the first synthesis of lysergic acid derivatives starting from the ergot clavine alkaloids (Scheme 14). Elymoclavine (55) was oxidized with manganese dioxide to give the lOa-methoxy-~8,9_lysergaldehyde (56). The lOa-methoxy-lysergic acid methyl ester (ll) was prepared from 56 by cyanide-catalyzed oxidation in methanol with active manga nese dioxide. The lO-methoxy group was then removed by reduction with zinc and acetic acid to give the lysergic acid methyl ester (2lb). Gilman 76 used a modification of the above procedure to produce ami des from a,B-unsaturated aldehydes. Based on this work it should be possible to produce lysergic acid ami des using elymoclavine as . starting material. The ~8,9_lysergaldehyde (~) has been proposed as an intermediate in the biosynthesis of ergolines40 and, therefore, its synthesis has been a subject of interest to many investigators, including those in this laboratory. It has not been found in nature, however, and pre vious attempts to synthesize it have been unsuccessful. Lin77 attempted the oxidation of elymoclavine (~) by DMSOjacetic anhydride (Scheme 15). Instead of the expected ~8,9_1ysergaldehyde (~), the enol acetate of ~9,lO-lysergaldehyde (58) was obtained. Attempts to hydrolyse this compound to the ~9,lO-lysergaldehyde (~) were not successful.

As mentioned earlier, we were able to oxidize e1ymoclavine (~) to the lOa-methoxy-~ 8,9-lysergaldehyde (56) with manganese dioxide 37

SCHEME 14

CH20H CHO Mn02/MeOH ~N-CH3 ------~~ bN- CH 3 H-HH CH30-- H 55 56

Mn02/KCN/MeOH

COOCH3 Zn/HOAc }---N- CH 3 CH30-HH 31 38

SCHEME 15

CH20H H-HH~N-CH3 55 t CHO

N-CH 3 H--QH

in methanol (Scheme 14).43 Attempts to remove the lO-methoxy group of the aldehyde, however, proved unsuccessful. Previous attempts to oxi dize elymoclavine (~) with a number of oxidizing agents, including

Cr03/pyridine,78 argentic picolinate,79 and DMSO,80 also had proven unsuccessful. CHAPTER III

RESULTS AND DISCUSSION

Photochemical Synthesis of 8-Methylergoline As mentioned earlier, the clavine ergot alkaloids possess signi ficant pharmacological activity,4 although they are not currently ex ploited clinically. A great deal of interest has been generated re cently in the synthesis of novel ergolines which may show enhanced or modified activities. An example of this is the synthesis of ergoline ethers, such as nicergoline, which have shown increased activity from the addition of an alkoxy group. It is, therefore, of interest to de velop new synthetic procedures for these types of compounds. The photochemical addition of water to the clavine alkaloid lyser gene (~) has been observed by Shough and Taylor (Scheme 5).57 The resulting lO-hydroxyagroclavine (26a) was identical to a compound which they had previously obtained by peroxidase oxidation of agroclavine. They also found that the lO-hydroxyagroclavine (26a) was unstable to aqueous acid and readily rearranged to the 8-hydroxy derivatives seto clavine (27a) and isosetoclavine (28a). Setoclavine (27a) was then observed to undergo a second photochemical addition of water to give the lumi-I and lumi-II derivatives 29a and 30a, respectively, along with some rearrangement back to the lO-hydroxyagroclavine (26a) (Scheme 5). The possibility of the same reactions occurring in alcohols 40 to give the 10-alkoxy, 8-alkoxy and 8,10-dialkoxy derivatives was the purpose of the present study. A series of preliminary photoreactions were run to determine the optimum reaction conditions and to learn something of the number and nature of the photoproducts. Small amounts (5 mg) of lysergene were o dissolved in the various alcohols and irradiated at 3600A under various conditions. The reaction mixtures were monitored by TLC either directly or after extracting with chloroform. The reaction products were visualized by viewing under long wavelength UV light and by spraying with Ehrlich's reagent. The initial photoaddition was found to occur most efficiently at room temperature. Cooling to O°C inhibited the reaction while heating to 40°C caused excessive decomposition. When the alcohol solutions were degassed and the reactions run under a nitrogen atmosphere there seemed to be better yields with less decomposition. In all cases and under all conditions the final reaction mixtures were dark red in color. TLC examination of the methanol and ethanol reaction mixtures were encouraging. The products seemed to be analagous to those ob tained by the photoreaction in water (Figure 3). After one hour, the methanol reaction showed a major product, 1I1M,1I in good yield at Rf 0.35 (CE). Some decomposition products remained at the origin. After two hours, the ethanol reaction also showed a major product, 11E," at R O.27 (CE) along with a trace of a similar product, 112E,1I at f Rf 0.65 (CE). In the ethanol reaction, however, there was a significant 41

"2EII ...... ~ ...... Lys. ." ...... -, '., .. ' ...J .. .. ' . . ' ...... t'...... :-:...... ' ...... Q 0 a 0 , Agro. 0 Q~E" "1MP It . .. .. W M E I-P- 1-8. L+A

W = Water 1- P = Isopropanol M = Methanol 1.- B = !- Butanol E = Ethanol L = Lysergene and agroclavine standards

FIGURE 3. PHOTOREACTION OF LYSERGENE IN ALCOHOLS 42 amount of un reacted lysergene and more decomposition was occurring. The isopropanol and t-butanol reactions did not give the desired pro ducts even after six hours (Figure 3). Traces of compounds similar

to "2E" were seen at Rf 0.65 (CE) in both cases but the major compo nents of the reaction mixtures were unreacted lysergene and a signifi cant amount of decomposition products remaining at the origin on TLC. Compounds "1M" and 1I1E" were nonfluorescent under long wavelength UV light and gave a yellow-brown color with Ehrlich's reagent. Their color reactions and TLC mobilities were similar to those of the 10- hydroxyagroclavine (26a) obtained from the photoreaction in water. Therefore, 1I1Mil and 1I1EI! were tentatively identified as the lO-methoxy agroclavine (60) and lO-ethoxyagroclavine (£1) respectively. Compound "2E" and the traces of products from the isopropanol and t-butanol· reactions showed the same yellow-brown color reactions as 1I1M" and "1E,JI however, they were fluorescent under UV light. Because of their fluoresence, we tentatively believed them to be the 8-alkoxy deriva tives. A series of preparative photoreactions were run in methanol and ethanol (Scheme 16). Large scale reactions were not run in isopropanol and !-butanol since the previous preliminary reactions did not yield the desired products. After four hours, the methanol reaction seemed to be complete. The ethanol reaction still contained a significant amount of unreacted lysergene, however. Longer reaction times did not seem to increase the yield, as judged by TLC, but only resulted in more decomposition. Great difficulty was encountered in trying to 43

SCHEME 16 CH3 ~N-CH3 CH30~H 60

work up and purify the products of these reactions. Column chromato graphy was unsuccessful as was preparative layer chromatography (PLC). The reaction mixtures seemed to be highly unstable and could not be manipulated for very long without completely decomposing. It became apparent that the 10-methoxyagroclavine (60) was much more unstable and more difficult to workup than the 10a-methoxY-6 8,9_lysergaldehyd~3 (56) and the 10-methoxylysergic acid derivatives. 54 After numerous modifications of the workup procedures, a method was developed which gave the lO-methoxyagroclavine (60) in about 15% 44 yield. Throughout this procedure it was found necessary to protect all solutions from light. The impure reaction mixtures seemed to be very light sensitive. The pure compound, however, was not as unstable as these impure residues. We were eventually able to isolate compound 60 in 47% yield. Attempts to isolate the product from the photoreaction in ethanol were still unsuccessful, however. It is appropriate at this point to mention the difficulty and ex pense involved in obtaining the starting alkaloid for these reactions. The ultimate source of most of the alkaloids used in this study was the Claviceps fungus. Due to our limited fermentation capacity and the relatively long growth period for this fungus, only a limited amount of alkaloid was available during a given time period. It was, therefore, not possible to commit unlimited amounts of starting ma terial in an attempt to isolate low yield products from these reactions. The identity of the 10-methoxyagroclavine (60) was confirmed by

examination of its NMR and mass spectra. The NMR spectrum (CDC1 3) was very similar to that of agroclavine. A new three proton singlet at 3.066 indicated the presence of a l11ethoxy group, however. The absence of a one proton multiplet at 3.746 in the NMR and the absence of an M-l peak in the mass spectrum8l ,82 indicated that the methoxy group was located at C-10. The mass spectrum also showed a molecular ion

at ~/~-268 which was consistent with a molecular formula of C17H20N20.

An intense peak at ~/~ 236 (M-CH 30H) was also present. The configuration at C-10 was assigned using the NMR method of Bernardi (Table 2).59 Bernardi has shown that for lO-alkoxyergolines 45 with the lOa configuration, the chemical shifts of their piperidino methyl groups (N-CH 3) fall near the range 2.40-2.498. Compunds with the lOB configuration, however, have N-CH 3 shifts near the range 2.20- 2.258. Although Bernardi's work involved only the dihydro derivatives and our compounds are ~8,9 derivatives, subsequent chemical shift data for ~8,9 derivatives of known configuration have been consistant with

Bernardi's analysis (Table 2). Since the chemical shift of the N-CH 3 group of our 10-methoxyagroclavine (60) was at 2.460 we assigned it the lOa configuration. With only one isomer produced by the photoreaction, it was not possible to verify Bernardi's method by comparing the N-CH 3 shifts of the lOa and lOS isomers. Therefore, an attempt was made to verify our assignment by direct comparison to a compound of known configuration. Since Bernardi 54 and Kornfeld 83 had previously verified the configuration of the 10a-methoxy-~8,9_lysergaldehyde (56), it was thought that reduction of the C-17 aldehyde would give the 10a-methoxyagroclavine (60) which could then be compared to our product from the photoreaction (Scheme 17). Reaction of 56 with ethanedithiol gave the thioacetal

(62) (molecular ion at ~/~ = 358). Attempted desulfurization with Raney nickel, however, was unsuccessful. Instead of the expected 10- methoxyagroclavine (§Ql, the major product appeared to be lysergene

(25). Verification of the configuration was not possible by this method and will, therefore, have to be based solely on Bernardi's analysis of chemical shift data. It seems, then, that the photoaddition of alcohols to lysergene is useful only for the synthesis of the 10a-methoxyagroclavine (60). 46

SCHEME 17

TsOH

Raney Ni EtOH REFLUX

CH3

N- CH3 CH30-b H 60

As mentioned earlier, Bernardi 59 was able to obtain the higher 10- alkoxy derivatives of dihydroelymoclavine by equilibration of the 10- methoxy derivative in acidic solutions of the appropriate alcohol. In our case, however, the acid lability of the ~8,9 double bond pre cluded the formation of 10-alkoxy derivatives by this method. It was possible, though, to synthesize the series of 8-alkoxy derivatives by this method. A series of preliminary reactions were run at various concentrations of different acids to determine the best conditions for the 47 equilibration. 10a-methoxyagroclavine (5 mg) was dissolved in 5 ml of methanol. Hydrochloric, phosphoric, acetic, succinic, and tartaric acids were used at concentrations of O.lM and O.OlM to catalyze the equilibration. After one hour only the O.lM hydrochloric acid solu tion had completely reacted but extensive decomposition had also occurred. After 24 hours, all of the so~utions had completely re acted and showed varying degrees of decomposition. The O.lM succinic acid solution seemed to give the least decomposition so this is what was used in the preparative reactions. The equilibration of 10a-methoxyagroclavine (60) was repeated in ethanol, ~-propanol, isopropanol, ~-butanol, and i-butanol at a con centration of O.OlM succinic acid (Scheme 18). The 8-alkoxy derivatives were isolated in yields of about 40% to 60%. In the case of the methanol reaction, it was found that addition of succinic acid

SCHEME 18

ROH/H+

63, R = CH3 64, R = C2H5 65 , R = !!. - C3 H7

66, R = l-C3H7 67, R = n- C4 Ha 48 directly to the methanol reaction mixture from the initial photoreac tion of 1ysergene (..e.) was more convenient. This results in complete rearrangement to the 8-methoxy derivative and avoided loss due to workup of the i ntennedi ate 1Oa-methoxyagroc 1avi ne (60). All of the products were fluorescent under UV light indicating that the double bond had shifted from the 8,9 position to the 9,10 position. Their TLC mobilities ranged from 0.58 to 0.69 in the CE solvent system, similar to that of setoc1avine, the 8 -hydroxyagro- c1avine derivative. They also gave the now familiar yellow-brown color reaction with Ehrlich's reagent. Comparisons of the NMR spectra

(CDC1 3) with that of the 10a-methoxyagroclavine (60) showed the ab sence of the -OCH3 signal at 3.068 in all cases and the appearance of new absorptions consistent with the appropriate alcohol (Table 4). The mass spectra showed molecular ions consistent with the molecular formulas of the respective 8-a1koxy compounds (Table 4). On the basis of this data it was concluded that the products of the reactions were indeed the 8-alkoxy derivatives. As in the case of the 10-alkoxy derivatives, only one isomer of the 8-a1koxy compounds was isolated. These isomers were considered to be the 8a compounds based on their TLC mobilities and on the prev ious experiences of Shou9h,S7 Kornfe1d,83 and Bernardi. 60

9 10 . °d d . to Previous experience with the ~' -lyserglc aCl erlva lves indicated that water can be added across the 9,10 double bond. We therefore, thought that this could also be accomplished with the 8- alkoxy compounds to give the 8,10-dialkoxy derivatives. TABLE 4

Proton Magnetic Resonance and Mass Spectral Data for 8-Alkoxy Derivatives

Molecular Compound NewAdsorption in PMR(CDC1 3) Ion

8-methoxy 3.350,s,(3H) 268 8-ethoxy 1 . 1 , t, (3H) 3.620,m,(2H) 282 8-n-propoxy 0.880, t, (3H) ; 1.530,m,(2H) ; 3.590 ,m, (2H) 296

8-isopropoxy 1 . 05° , t , ( 6H) 4.25 0,m,(lH) 296 8-n-butoxy 0.890 , t, (3H) ; 1.400,m,(4H) ; 3.590 ,m, (2H) 310

-Po 1..0 50 All attempts to produce the 8,10-dialkoxyagroclavines by a second photoaddition across the 9,10 double bond proved unsuccessful. Shough and Taylor had previously observed that traces of 10-hydroxy agroclavine (26a) were produced in addition to the expected lumi deri vatives, when a tartaric acid solution of setoclavine (27a) was irradiated at 3600 o A. When the irradiation of setoclavine (27a) was repeated at pH 4.6, the 10-hydroxyagroclavine (26a) was isolated in 30% yield. Similar results were obtained when we irradiated the 8- alkoxyagroclavines in the appropriate alcohol in an attempt to produce the 8,10 dialkoxyagroclavines. When 8-methoxyagroclavine (63) was irradiated in methanol the 10-methoxyagroclavine (60) was the major product after 30 minutes. Traces of two other minor products at Rf 0.10 and 0.44 (CE) were seen on TLC but they were not present in isola table amounts. These two products were nonflorescent under UV light and showed the same violet-blue color reaction with Ehrlich's reagent as the dihydroclavine alkaloids. It was thought that these minor pro ducts could be traces of the isomeric 8,lO-dimethoxyagroclavines. This is only speculation, however, since they were only observed in trace amounts. When hydrochloric or succinic acids were added to the methanol solution irradiation still produced only lO-methoxyagroclavine (60) as the major product. Irradiation of the 8-ethoxyagroclavine (64) in ethanol also yielded what appeared to be the 10-ethoxyagrocla vine (&1) along with a significant amount of lysergene (~). When the 8-~-propoxy-, 8-isopropoxy-, and 8-~-butoxy derivatives were irradiated in ~-propanol, isopropanol, and ~-butanol respectively, the 8-alkoxy compounds were converted to lysergene (25) after one 51 hour. No traces of the lO-alkoxy or 8,lO-dialkoxy products were seen. Longer irradiation times resulted in extensive decomposition. All of the above reactions were only run on a small scale and the reaction mixtures were studied by TLC. Because of the disappointing results no preparative scale reactions were run. The failure of this reaction was unexpected since the addition of water and methanol to the 9,10 double bond had been considered a general reaction for ~9,lO ergolines. Our experience shows that this is not the case, especially with the presence of a labile group at position 8. Actually, the conversion of the 8-~-propoxy, 8-isopropoxy, and 8-~-butoxy derivatives to lysergene (~), might be rationalized by considering that the attempted photoaddition of these alcohols to lysergene (25) resulted in no 1,4 addition products. In fact, the only observed products of these photoaddition reactions were trace amounts of what appeared to be the 8-alkoxy derivatives along with significant decomposition. It appears that when the alcohol has a large stearic bulk, the kenetics of 1,4 addition'may become unfavor able and a 1,2 addition to form the 8-alkoxy derivatives would become slightly more favored. The equilibrium of the 1,2 addition, however, would seem to be predominately on the side of lysergene (25). There fore, under the conditions of the photoreaction with these bulky alcohols, lysergene (~) would be converted to the 8-alkoxy deriva tives in trace amounts while the 8-alkoxy compounds would be converted almost completely back to lysergene (~). It is also possible that the 1,4 addition product is highly unstable and quickly rearranges to the 8-alkoxy compound, even in the absence of the acid catalyst. 52

This s~ems unlikely, however, since continuous formation and rearrangement to the 8-alkoxy derivatives should accumulate more than trace amounts of these products and at least trace amounts of the 1,4 addi tion product could be expected.

Nonphotochemical Synthesis of 8-Methylergoline Ethers Two nonphotochemical methods for the synthesis of ergoline ethers have recently been developed. Bernardi 60 produced the lOa methoxY-6 8,9-lysergic acid methyl ester (47) via the solvomercura tion-demercuration procedure of Brown and in this lab we were able to produce the lOa-methoxY-6 8,9-lysergaldehyde by manganese dioxide oxidation of elymoclavine (~) in methanol. 43 Because of the pre viously stated interest in novel ergot alkaloids of this type, we thought it would be important to determine if these synthetic methods could be generally applied to the synthesis of ergoline ethers from the clavine alkaloids.

Lysergene (~), lysergine, agroclavine (68), elymoclavine (~), and lysergol were reacted with mercuric acetate according to Ber nardi's60 procedure. From the results of these experiments it appeared that the clavine alkaloids are not susceptible to solvomercuration by mercuric acetate. In almost all cases, the starting alkaloids were recovered unchanged. Bernardi's procedure was modified by add ing a sodium chloride solution to the reaction mixture in an effort to form the HgCl complex and facilitate isolation of a product. 84 This proved unsuccessful, however, as unreacted starting material was still recovered from the reaction. When a large excess of mercuric 53 acetate was used in the reaction with lysergene and lysergine, a mix ture of unreacted starting material and trace amounts of two minor products was obtained in both cases. These two products were non fluorescent under UV light and gave a violet-blue color reaction with Ehrlich's reagent. Comparison with standard reference compounds showed them to have TLC mobilities similar to those of agroclavine (68) and dihydroagroclavine. It seems, therefore, that Bernardi ' s60 procedure is useful only for the lysergic acid series and not for the c1avine alkaloids. When active manganese dioxide was added to a solution of agro c1avine (68) in methanol two products were formed (Scheme 19). After 10 minutes, the major product appeared to be the 10-methoxyagroc1avine

(60) while the minor product appeared to be 1ysergene (~). A signi ficant amount of unreacted starting material was also present. Longer reaction times resulted in decreasing yields of the 10-methoxyagro c1avine (&Q) and increasing yields of lysergene (25). After six hours only lysergene (25) and unreacted starting material remained. Attempts to isolate the suspected 10-methoxy derivative failed since, as re ported earlier, the instability of this compound makes it difficult to isolate such small amounts. Bases on TLC comparisons, however, this product is still definitely thought to be identical to the 10a methoxyagroclavine (60) obtained from the photoaddition of methanol to 1ysergene (25). It appears then that the manganese dioxide reaction in methanol is efficient only in the presence of an 8-hydroxymethyl group. With other clavines it is not as efficient as the photoreac tion for the production of 10-methoxyagroclav;ne (60). 54

SCHEME 19

CH3

.,.. ON- CH 3 + CH30 - H 60

~~ __M_n_O_2_/_1_-_8_U_0_H ______~

The above reaction was also repeated with i-butanol as solvent in order to determine if manganese dioxide oxidation of agroclavine (68) could be a practical synthesis of lysergene (25) (Scheme 19). After one hour only about 60% of the agroclavine had reacted and lyser gene (25) appeared to be the major product along ~ith some decomposi tion. Longer reaction times did not improve the amount of agroclavine (68) converted to lysergene (25) and only resulted in more decomposi ton. Pure lysergene (25) could be isolated in only about 20% yield. Its mass spectrum and NMR spectrum were identical with those of authentic lysergene (25).82 Because of the poor conversion and low yield this did not seem to be a practical method for the synthesis of 1ysergene (25). 55 Synthesis of 8-Hydroxymethylergoline Ethers The 8-hydroxymethylergoline ethers are of interest because of their structural similarities to the potent a-adrenergic blocker, nicergoline. Bernardi 60 first produced 10a-methoxyelymoclavine (48) by reduction of 10a-methoxylysergic acid methyl ester (47) (Scheme 38 11). It was the 8,9-dihydro derivative of 48 which Bernardi con densed with 5-bromo-nicotinic acid to give nicergoline. When we synthesized the 10a-methoxy-~ 8,9-lysergaldehyde (~),43 it was rea 1i zed that the C- 17 aldehyde coul d a1 so be reduced to gi ve the 10a methoxyelymoclavine (48). Although Bernardi had previously synthe sized this compound, it is important to stress the fact that his synthesis utilized lysergic acid as starting material whereas our pro cedure would start from the clavine alkaloid elymoclavine (~). It has already been stated that there may be future advantages to using the clavine alkaloids as starting materials for the synthesis of clinically important ergot alkaloids. The loa-methoxy-~ 8,9-lysergaldehyde (56) was reacted with sodium borohydride in ethanol for 15 minutes (Scheme 20). TLC showed that the aldehyde had completely reacted to one major product. The product was nonfluorescent under UV light and gave the same yellow-brown color reaction with Ehrlich's reagent as the previously prepared 10- alkoxy compounds. The mobility on TLC, Rf 0.20 (CE), was lower than the 10-alkoxy agroclavines, and consistent with the presence of a hydroxymethyl group at the 17 position. The NMR spectrum and mass spectrum were identical to previously published data for 10-methoxyely- 56

SCHEME 20

CH20H

I) NaBH4 -----..,..... bN- CH 3 2) Na OH CH30-- H 48

MeOH/H+

moclavine (48).60 The success of this method is significant since it had already been shown that other photochemical and nonphotochemical procedures for producing ergoline ethers were unsuccessful with elymo-

c 1a vine (~). In his search for novel ergoline derivatives which might show

anti-prolactin activity, Kornfeld83 was able to rearrange the 10a methoxyelymoclavine (48) in various solvents to form the 8-acetoxy, 8-methylthio, and 8-methoxy derivatives. This reaction was similar 57 to that observed by us for the 10a-methoxyagroclavine (60) in alcohols and was said to be a general reaction of ~8,9_10 alkoxyergolines. 83 We were also able to rearrange the 10a-methoxyelymoclavine (48) to the 8-methoxy derivative in about 40% yield (Scheme 20). Again, the important difference of our procedure was the fact that the starting ma terial for this sequence of reactions was the clavine alkaloid elymoclavine (55).

S nthesis of L ser ic Acid Amides from Elymoclavine 55 Most of the clinically useful, nonpeptide, ergot alkaloids are currently obtained by partial synthesis from lysergic acid. 19 The lysergic acid used for this purpose is obtained either from field cultivated ergot or by fermentation procedures. There are, however, serious problems with these methods including variable yields and un stable fungal strains which are difficult to maintain. 2l ,22 There is a great deal of interest, therefore, in developing new sources for these compounds. An interesting possibility is the use of the clavine alkaloids as starting material for the partial synthesis of these clinically important ergot alkaloids. One of the major advantages to such an approach is the availability of the clavine alkaloids from high yielding, stable and easily maintained strains of the Claviceps 23 fungus. The synthesis of the 10a-methoxy-6 8,9-lysergaldehyde (~) from elymoclavine (55) opened the door to a possible new source for the synthetic production of lysergic acid derivatives. By using the 58 cyanide catalyzed oxidation procedure developed by Corey,44 (Scheme 14), we managed the first successful synthesis of lysergic acid from a clavine alkaloid. Gilman 76 reported that by using a modification of Corey's procedure, he was also able to produce amides from a,6- unsaturated aldehydes (Scheme 21). It was suggested then that this modified Corey procedure could prove to be of general utility for the synthesis of lysergic acid amides from elymoclavine (~). We, there fore, decided to attempt the synthesis of lysergic acid amide, lysergic

SCHEME 21

"- /' /' C=C "- C==C CN / ",/ / "CHO C "OH

Mn02

MeOH ~ / C==C / "'C-CN II o

GILLMAN'S RNHZ MODIFICATION

'" C==C / / "'CNHR II o 59 acid piperidine amide and ergonovine in order to determine the usefulness of this reaction.

Following Gilman's general procedure, with NH 3, lOa-methoxy- 68,9-lysergaldehyde (56) was converted to one major product which was isolated in approximately 66% yield (Scheme 22). We assumed this to be the lOa-methoxy-6 8,9-lysergic acid amide (70). The mass spectrum of this compound showed a molecular ion at ~/~ = 297, consistent with a molecular formula of C'7HlgN302" The rest of the spectrum was al most identical to that of the lysergic acid amide (11).82 The NMR

SCHEME 22 o II CHO C-NH2

Mn02/CN-/NH:3 )-\- 3 ------"".,.. bN-C H:3 CH CH30-~H CH:30 -- H 56 70

Zn/HOAc

oII . H'h~2 H~CH3 +

71 60 spectrum was also similar to publjshed data for the lysergic acid amide 84 except for the presence of an additional three proton singlet at 3.008 for the 10a-methoxy group. Although the amide NH protons were not readily apparent in the NMR spectrum, the IR spectrum showed the appropriate NH stretching band at 3470 cm- l and amide bands at 1650 cm- l and 1675 cm- l . Based on this, we decided the product was indeed the 10a-methoxy-~ 8,9-1ysergic acid amide. The crude product from the above reaction was reduced directly with zinc dust and acetic acid (Scheme 22). A mixture of two similar products was isolated in a crude yield of 2:0%. These two products were fluorescent under UV light and had mobilities on TLC identical to those of the lysergic acid amide (11) and isolysergic acid amide

(72). Separation by PLC gave TLC pure lysE~rgic acid amide (11) and isolysergic amide (72) in 3% and 5% yields respectively. Some diffi culty was encountered in purifying the low Rf compound since it seemed to isomerize easily to the high Rf compound. This was to be expected if the products were the lysergic and isolysergic acid ami des. Sub- sequent examination of the IR, NMR, and mass spectra of the two products did show them to be identical to the published data for the lysergic acid amide (11) and isolysergic acid amide (1£).83,84,10 When the reaction was repeated with piperidine, similar results were obtained, with a crude product being 'isolated in 70% yield

(Scheme 23). The mass spectrum showed a molecular ion at ~/~ = 365 which was consistent with a molecular formula of C22H27N302. There were also peaks at 333 and 248 corresponding to loss of methanol and 61

SCHEME 23 o CHO 110C- N

h N- CH3 CH30-HH 56 73

Znl HOAc

o C-OII H~D-CH3HH + 74

piperidine. The NMR spectrum showed the three proton singlet of the methoxy group at 3.206 along with 6 proton and 4 proton multiplets from the piperidine ring at 1.666 and 3.596. Again, the aldehyde absorption at 9.676 was missing. The IR spectrum showed typical amide absorption at 1620 cm- l . The above data are consistent with the assignment of lOa-methoxy-~ 8,9-lysergic acid piperidine amide ell) as the product of the above reaction. The crude product from the above reaction was reduced as before with zinc dust and acetic acid. Two major products were isolated and separated by PLC to give yields of 13% and 22% respectively. The mass 62 spectra showed both compounds to have molecular ions at ~/~ = 335 consistent with a molecular formula of C21H2SN30. The NMR spectra were identical with that of the 10a-methoxy-~ 8,9-lysergic acid piperi dine amide (73) except for the fact that the 3 proton singlet of the 10-methoxy group was missing. Both compounds were fluorescent under UV light indicating a double bond shift to the 9,10 position of the ergoline nucleus. The IR spectra again showed the typical amide absorptions at 1620 cm -1 . These compounds were, therefore, identified as lysergic acid piperidine amide (74) and isolysergic acid piperidine amide (~). The individual isomers were assigned on the basis of their TLC mobilities. Since the above reactions were reasonably successful with relatively simple amines, it was decided to attempt the synthesis of the clinically useful ergot alkaloid, ergonovine, by this procedure. This synthesis necessitated the use of a slightly more complicated amine, L-2-amino-l-propanol. The presence of a primary hydroxyl in this molecule caused some concern regarding the formation of the ester as well as the expected amide. It was thought, however, that forma tion of the amide would be favored in this case since the previous reactions showed only traces of isopropyl ester formation from reac tion with the solvent. When the reaction was run with L-2-aminopropanol, then, a mixture of two products was seen on TLC (Scheme 24). The minor product, which was believed to be the ester, was not present in an isolateable amount, however. Attempts to purify the reaction mix ture and isolate the major product led only to complete decomposition. 63

SCHEME 24

CHO ~N-CH3 CH30-WH 56

Zn/HOAc

o CH'2 CH3 II I...J oII I C-NHCH C-NHCH I I I CH20H HQIICH20H + ~ N-CH 3 H 77 78

A semi-pure, noncrystalline product was obtained by chromatography on silica gel but the yield was poor. The mass spectrum showed a molecular ion at m/~ = 355 which was consistent with a molecular formula of C20H25N303. Since attempts at purification failed, the crude product from this reaction was reduced directly with zinc dust and acetic acid. The zinc/acetic acid reduction of the above crude product gave a complex mixture of products. Approximately fifteen Ehrlich's positive compounds were seen on examination by TLC. Only two of these products 64 were fluorescent under UV light and their TLC mobilities were identical to the ergonovine and ergonovinine standards. Attempts to isolate and purify these products were unsuccessful due to the small amounts and the complex nature of the reaction mixture. Further examination of TLC, however, showed these two products to have identical mobilities, color reactions, and fluorescent properties with ergonovine and ergonovinine in the CE, CEA, and EED solvent systems. The use of the modified Corey procedure for the synthesis of lyser gic acid amides was not as successful of the 10 -methoxy lysergic acid amides. Two major problems were encountered with the reduction of the lO-methoxy group. The yields of all three of the above reductions were only fair to poor and were accompanied by extensive decomposition. With zinc and acetic acid a number of side reactions are possible including reduction of double bonds, hydrolysis of the amide, and acetylation of the ergolinne nucleus. A large degree of epimerization also oc curred with the isolysergic acid amides being the major products. A certain amount of epimerization had been expected due to the strongly basic workup conditions85 and it was anticipated that the lysergic acid amides could be regenerated by the methods of Hofmann. 86 It seems that the usefulness of this procedure to produce lyser gic acid amides depends on either finding a more efficient method of reducing the 10-methoxy group or, ideally, avoiding the necessity of such a reduction step. This brings us back to the desirability of synthesizing the unsubstituted lysergaldehydes. The modified Corey procedure could then be applied to these compounds to produce the lysergic acid ami des directly without need for further modifications 65 in their structures. As mentioned earlier, a number of investigators have tried unsuccessfully to produce the lysergaldehydes by a variety of oxidation and reduction procedures. The use of selenium dioxide as an oxidizing reagent has not been tried, however. This reagent has proven to be of use in the oxidation of a,6-unsaturated methyl or hydroxymethyl groups to aldehydes.'87 88 Therefore, it was anticipated that perhaps this reagent could also be used to oxidize certain clavine alkaloids to the lysergaldehydes. Agroclavine (68) and elymoclavine (55) were refluxed with selenium dioxide in various solvents. No reaction, other than some decomposition, was seen in methanol, methanol/water, methanol/acetic acid, or dioxane. When the reaction was run in glacial acetic acid a product was formed in poor yield along with extensive decomposition. Because of the poor yield, attempts to isolate this product were unsuccessful. Based on previous experience with the 10a-methoxy-~ 8,9-1ysergaldehyde

(~), this product did not appear to have the expected TLC characteris tics of the lysergaldehydes. It seemed, therefore, that selenium di oxide oxidation had joined the list of previous procedures which had proved unsuccessful in oxidizing the clavine alkaloids to the lysergaldehydes.

Summary of Results The major results of this study may be summarized as follows: 1. The photoaddition of methanol to lysergene was accom plished to give the 6,8-d;methyl-10a-methoxy-~ 8,9-ergoline (60). This reaction was not successful with the higher alcohols, ethanol, isopropanol, and i-butanol, however. This 66 photoreaction was found to be the most efficient method for the synthesis of compound 60 since other methods such as oxymercuration-solvomercuration and manganese dioxide oxi dation in methanol were unsuccessful. 2. The 5,8-dimethyl-8-alkoxy-~ 9,10_ergolines 63, 64, 55, 56, and &L were produced in 40-60% yields by an acid cat catalyzed equilibration of compound 50 in methanol, ethanol, n-propanol, isopropanol, and Q-butanol, respectively. 3. The attempted synthesis of a 5,8-dimethyl-8,10-dimeth oxyergoline by a second photoaddition of methanol was unsuccessful. It seems that the formation of lumi-type derivatives by photoaddition of alcohols across the 9,10 double bond is not as general a reaction as previously thought. 8 9 4. The 5-methyl-10a-methoxy-~ '-8-hydroxymethylergoline (48) was prepared by reduction of 10a-methoxy-~ 8,9_ lysergaldehyde (~). An acid catalyzed equilibration in methanol then afforded the 5-methyl-8-methoxy-~ 9,10_8_ hydroxymethylergoline (59). Kornfeld83 also produced these and similar compounds by another route starting from lysergic acid. The important difference of our method is that these compounds were produced starting from the more readily available clavine alkaloid elymoclavine. 5. The cyanide catalyzed, manganese dioxide oxidation of 10a-methoxy-~ 8,9-lysergaldehyde (56) was shown to be a useful method for the production of lysergic acid ami des. 67 SCHEME 25

COR COR CH20H

CN- CH3 ---+ )-"\-CH3---+ 0 N- CH3 HH CH30+-fH Ro-HH 1l 23 32,33,34,36 I I I t COR CH20H R CH20H

CH3 N CH3 ----' b - ---: { t~CH3 CH30-b-H CH30- H -,31 -47 48 -49,69- I CH20H CHO CH3

CH3 • )< b~CH3 CH30.. -b- H b~CH3

55 56 t CH2 CH3 CH ROD CH O~CH3 .. Q- 3 .. ~ :- 3 CH30- H 25 60 -63-67- --...... PREVIOUS WORK ... RESULT OF THIS STUDY 68 A number of amides, including ergonovine (lL), were syn thesized by this method. This is the first time that lysergic acid amides have been successfully produced starting from the clavine alkaloid elymoclavine. This procedure could, therefore, be a feasible alternative for the production of commercially important lysergic acid amides. A general overview of the ergoline ethers synthesized to date, including the results of this study, it given to Scheme 25. As can be seen, the new series of 8-methylergoline ethers was synthesized in this study along with the development of a new route to the 8-hydroxymethylergoline ethers and the lysergic acid amide ehters. It also appears that the 8-formyl and the 8-hydroxymethylergoline ethers could provide for future modifications at C-17 to give a variety of new derivatives. This could provide a host of compounds for future struc ture-activity studies. CHAPTER IV

EXPERIMENTAL

General Procedures Thin layer chromatography (TLC). Thin layer chromatography was 89 performed according to Stahl. 35 g of Silica Gel G (EM Laboratories, Darmstadt, Germany) was suspended in 70 ml of distilled water and spread on clean glass plates of (5 x 20 cm or 20 x 20 cm) to a thickness of 0.25 mm. The plates were then air dried for 24 hours before use. Ergot alkaloids were detected on developed chromatograms by view ing under long wavelength (366 nm) ultraviolet light and by spraying with Ehrlich1s reagent. 90 This reagent is a solution of Q-dimethyl- aminobenzaldehyde (lg) in conc. HCl (10 ml) and EtOH (40 ml). The following solvent systems were used: CHC1 3-EtOH (5:1,CE); CHC1 3- MeOH (7:3 CM); EtOAc-EtOH-DMF (13:1:1, EED); Et2NH - CHC1 3 (1:9, DC). Preparative layer chromatography (PLC). Preparative plates (0.5 mm thickness) were prepared as above using 70 g silica gel in 130 ml distilled water. Good separation was usually obtained when approximately 15 mg of total alkaloids were applied to one 20 x 20 cm plate. Alkaloid zones were located with UV light and by spraying one edge of the chromatogram with Ehrlich1s reagent. A clean glass plate was used to protect the rest of the chromatogram from the spray 70

reagent. The alkaloid zones were scraped off the plate separately and the alkaloids were eluted from the silica gel with MeOH. The extract was evaporated to dryness under reduced pressure and the resi dual silica gel removed by passing the alkaloids through a tartaric

acid (1%) - CHC1 3 wash cycle. In the case of acid-labile alkaloids, the dry MeOH extract was dissolved in CHC1 3 and the solution filtered to remove residual silica gel. Column Chromatography. Silica gel power (60-200 mesh, J. T. Baker Chemical, Phillipsburg, N.J.) and Fisher adsorption alumina (A-540) were used in column chromatography. Alkaloid/adsorbent ratios of 1:50 to 1:100 were generally satisfactory for these ergo1ines, de pending on the complexity of the mixture. Good separation was usually

accomplished by packing the absorbent wet in CHC1 3 and eluting with

CHC1 3 followed by CHC1 j -MeOH (1-10%) mixtures of gradually increasing polarity. Elution was usually at a rate of about 2 m1/min. and the eluates were monitored by TlC. Analytical methods. Infrared spectra (IR) were recorded on a Beckman IR-8 spectrophotometer in KBr. Proton magnetic resonance spec-

tra (PMR) were recorded on a Joel C-60H spectrometer in CDC1 3 or DMSO d6 with TMW or DSS as internal standards. Chemical shifts are reported in units (parts per million) from the standard. Mass spectra (MS) were recorded on a LKB model 9000 S spectrometer at 70 Kev and melting points were determined on a Thomas-Hoover apparatus and are uncor- rected. Elemental analyses were performed by Het-Chem-Co., Harrison-

ville, Missouri and all analytical samples were dried ~ vacuo in the 71

Preparation of Starting Material and Manganese Dioxide Elymoclavine and Agroc1avine. E1ymoc1avine and agroc1avine were isolated from cultures of Claviceps strain SO 58 obtained from Dr. J. E. Robbers, Purdue University, West Lafayette, Indiana. The strain 91 was maintained on NL406 agar slants at 5°C and transferred every three months to maintain viability and alkaloid production. Seed cultures were prepared in shake culture in the semisynthetic medium NL406 (200 mL) in one liter flasks for two weeks. Production cultures were grown in stationary culture in the dark at 24°C in the NL406 medium in 1 liter Roux bottles. The cultures were allowed to grow for 6-8 weeks after which the alkaloids were isolated by solvent ex 92 traction with CHC1 3 as previously reported. This strain generally produced 0.9-1.5 giL of total alkaloids which consisted mainly of elymoclavine (60-70%) and agroclavine (10-20%). Most of the elymo- c1avine was obtained directly by fractional crystallization from MeOH. The remaining alkaloid mixture was chromatographed on a silica gel column and eluted with CHC1 3 to provide agroclavine followed by CHC1 3-MeOH (95:5) to provide the remainder of the elymoc1avine. Other standard alkaloids. Setoc1avine, isosetoc1avine, penni clavine, isopenniclavine, lysergol, and lysergine were obtained by . 93-95 published procedures from agroclavine and elymoclavlne. 96 Lysergene (~). Elymoclavine (lOg) was dissolved in pyridine (250 ml) by slight heating. The solution was then cooled to O°C and p-toluenesulfonylchloride (8.6g) was added slowly with vigorous stir ring. The resulting red solution was stirred for 3 hours after which 72 it was allowed to gradually warm to room temperature and was stirred for another 1 hour. The reaction mixture was kept at O°C for 12 hours after which the light green precipitate (20.5g) was filtered and dried at 50°C under reduced pressure. This elymoclavine pyridine tosylate, without further purification~ was dissolved in EtOH (143 ml). 2N NaOH (214 ml) as added and the dark brown solution refluxed for 1 hour. The EtOH was evaporated from the solution and the black preci pitate (8.0g) filtered. This precipitate was chromatographed on an alumina (300g) column and eluted with CHC1 3. The lysergene was col lected and recrystallized from acetone to give 7.2g (87%); mp 243-

245°C (lit. mp 247-249°C); TLC, Rf 0.52 (CE); NMR~ MS identical to published spectra. 10a-Methoxy-~ 8,9-lysergaldehyde (56).43 Elymoclavine (2g) was dissolved in MeOH (400 mI) and Mn02 (Fatiadi) (20g) was added slowly with vigorous stirring. The mixture was stirred at room temperature for 12 hours, filtered, and washed with MeOH. The filtrate was evaporated to dryness under reduced pressure. The residue was dissolved in an aqueous tartaric acid solution (1%), made alkaline with NH 40H, and extracted with CHC1 3. After evaporating the CHC1 3, the res)due was crysta.llized from ethyl acetate to give 850 mg. The mother liquor was evaporated to dryness and a minimum amount of ethyl acetate added to give another 300 mg. The resulting mother liquor was evaporated and the residue set aside. These final residues from five 2g reac tions could later be combined and chromatographed on silica gel to give an additional 150 mg of the aldehyde. Recrystallization from

CHC1 3/hexane gave a total of 1.2g (57%) of small white needles; 73 mp 190-194°C (dec) (lit. 192-194°C): TLC, Rf , 0.B2 (CE): NMR, MS identical to published spectra.

Manganese dioxide (Attenburrow).97 KMn0 4 (95g) was dissolved in water (700 ml) and heated to 90°C. An aqueous solution of MnS0 4- H20 (75g/200 ml) and a solution of NaOH (49g/120 ml) were simultane ously added dropwise and with stirring over a period of 1 hour. Stirring was continued for another hour at 90°C after which the mix ture was slowly cooled. The warm suspension was filtered and the

Mn0 2 washed with large volumes of water until the filtrate was color less. The solid was dried overnight at 110°C and ground to a fine powder (90g) before use.

Manganese dioxide (Fatiadi).98 An aqueous solution of KMn0 4 (BOg/1L) was heated to 90°C and an aqueous solution of MnC1 2-4H20 (llOg/lL), also at 90°C was added gradually with stirring. The suspension was stirred for 2 hours at 90°C after which it was slowly cooled. This procedure was done in the hood due to the evolution of chlorine gas. The mixture was filtered and the Mn0 2 washed with large volumes of distilled water until the washings gave a negative chloride test. The solid was dried overnight at 110°C and ground to a fine powder (90g) before use.

Synthesis of Ergoline Ethers

Preliminary photoreactions of lysergene. A series of preliminary reactions were carried out to determine optimal conditions for the photoreaction and to learn something about the number and nature of the reaction products. 5 mg portions of lysergene (~) were dissolved 74

in 20 ml each of the following alcohols: methanol, ethanol, isopro panol, and !-butanol. Each solution was irradiated at a distance of 2 cm with longwavelength (366 nvn) ultraviolet light (Model X4, Ultra violet Products, San Gabriel, California). All the reactions were monitored by TLC. At room temperature the methanol reaction was com plete after 1 hour and the ethanol reaction after 2 hours. The iso propanol and !-butanol reactions, however, had not reacted signifi cantly after 6 hours. At DoC, the methanol reaction was not complete even after 4 hours and the other alcohol solutions had not reacted at all. When the alcohol solutions were irradiated in a sealed tube under a nitrogen atmosphere, the isopropanol and !-butanol solutions still failed to react. The absence of oxygen did seem to have a bene ficial effect on the methanol and ethanol reactions, however. TLC examination of these reaction mixtures showed a cleaner reaction with less decomposition. On TLC, the methanol reaction showed a major,

Ehrlich-positive, product, 1I1M,1I at Rf 0.35 (CE) and a small amount of what appeared to be agroclavine. The ethanol reaction also showed a major product 1I1E,1I at Rf 0.27 (CE) along with a trace of a similar product "2E" at Rf 0.65 (CE). A small amount of agroclavine was also present above "1E." The isopropanol and !-butanol reactions showed only traces of products which appeared to be analogous to 1I1E" and "2E.1I These reactions showed mostly unreacted lysergene and large amounts of decomposition products at the origin of the TLC plate. Compounds "1M" and 1I1EII were nonflourescent and showed a brown color with Ehrlich's reagent. They were thought to be 10a-methoxyagroclavine and 10a-ethoxygroclavine respectively. Compound 112E" was 75 fluorescent and showed the same brown color with Ehrlich's reagent. It was thought to be the 8-ethoxy derivative.

10a-methoxyagroclav;ne (60). 320 mg of 1ysergene (~) were dis solved in 200 ml of anhydrous MeOH. This solution was placed in a 500 m1, water cooled photoreaction vessel along with 1/2 inch of Linde 3A molecular sieve. N2 gas was bubbled through the solution during irradiation at 3600 A for 4 hours. The MeOH was evaporated leaving 320 mg of a red powder. This powder was chromatographed on an alumina column (12g) and eluted with CHC1 3. 250 mg of a pink powder was recovered from the CHC1 3 eluates and crystallized from acetone to give 170 mg (47%): m.p. 170-175°C (dec). TLC, Rf , 0.35 (CE) .NMR (CDC1 3): 2.46 (3H,s, N-Ch 3); 3.06 (3H,s, O-CH 3); 6.43 (lH,m, 9 - CH); 6.82-713 (4H,m, indole); 8.28 (lH,s" NH). MS: m/~

= 268 (M+), 253 (M+ - CH 3), 236 (M+ - CH 30H), 219, 192, 154, 117. 8-methoxy-6,8-dimethyl-6 9,10-ergo1ine (63). 19 of 1ysergene

(~) was dissolved in 1000 m1 of anhydrous NeOH and irradiated at 3600A° as described above. After 4 hours 0.295g of succinic acid was added to the red solution and placed in the dark overnight. The MeOH was evaporated and the residue dissolved in 400 m1 H20. This aqueous solution was made alkaline (pH 11) with NH 40H and extracted with 3 volumes of CHC1 3. The CHC1 3 was evaporated and the residue chroma tographed on an alumina column (100g). Elution with CHC1 3 provided .460g of 8-methoxyagroclavine which was recrystallized from acetone to give .400 9 (35%):m.p. l85-l90°C(dec). TLC, Rf , 0.58 (CE). NMR (CDC1 3): 2.500 (3H,s,N-CH3); 3.358 (3H,s,0-CH3); 6.318 (lH,m, 9 = CH); 76

6.83-7.14 (4H,m, indole); 7.99 (lH,s,NH). MS:m/~ = 268 (M+), 253

(M+ - Ch 3), 236 (M+ - CH 30H), 167, 154. 8-ethoxy-6,8-dimethyl-~ 9,10-ergoline (64). 50 mg of 10a-methoxy agroclavine (~) were dissolved in 50 ml EtOH and 50 mg succinic acid added to the solution. The solution was left in the dark for 18 hours with stirring. The EtOH was then evaporated and the residue dissolved in 50 ml H20. This aqueous solution was made basic and ex tracted with CHC1 3. Evaporation of the CHC1 3 yielded 43 mg of 8- ethoxyagroclavine which was recrystallized from acetone/ether. Yield

- 30 mg (60%): m.p. 163-l64°C (dec.). TLC, Rf , 0.65 (CD). NMR (CDC1 3): 1.12(3H,t,-CH3); 2.47(3H,s, N-CH 3); 3.62(2H,q, O-CH 2-); 6.3l(lH,m, 9 = CH); 6.86-7.23(4H,m, indole); 8.2l(lH,s, NH). MS: m/~ = 282(M+), 267(M-CH 3), 253(M-CH 3CH 2), 237(M-CH3CH 20). 8-n-propoxy-6,8-dimethyl-~ 9,10-ergoline (65). 50 mg of 10a methoxyagroclavine (60) was dissolved in 50 ml ~-propanol and 50 mg succinic acid added. After 18 hours in the dark the ~-propanol was evaporated and the residue dissolved in 50 ml H20. This aqueous solution was extracted with CHC1 3 in the usual manner. The CHC1 3 was evaporated and the residue crystallized from acetaone/ether to give

25 mg (50%); m.p. 163-165°C (dec.). TLC, Rf , 0.68 (CD). NMR(CDC1 3: 0.88(3H,t, -CH 3); 1.53(2H,m, -Ch 2-); 2.55(3H,s, N-CH 3); 3.59(2H,m, OCH,-); 6.33(lH,m, 9 = CH); 6.89-7.23(4H,m, indole); 8.12(lH,s, NH). ~ MS: ~/~ = 296(M+), 253(M-CH 3CH 2CH 2), 238, 167, 154. 8-isopropoxy-6,8-dimethyl-~ 9,10-ergoline (66). 50 mg of 10a methoxyagroc1avine (60) were dissolved in 50 ml isopropanol and 50 mg succinic acid added. After 18 hours in the dark the isopropanol was 77 evaporated and the residue dissolved in 50 ml H20. This aqueous solu tion was extracted with CHC1 3 in the usual manner. The CHC1 3 was evaporated and the residue crystallized from acetone/ether to give 20 mg (36%); mp l60-165°C (dec.). TLC, Rf , 0.60 (CE). NMR(CDC1 3): 1.05(6H,t,-CH3); 2.45(3H,s,N-CH3); 4.25(lH,m,0-CH-); 6.25(lH,m,9 = CH); 6.85-7.l7(4H,m,indole); 8.00(lH,s,NH). MS; ~/! = 296(M+). 8-n-butoxy-6,8-dimethyl-~ 9,10-ergoline (67). 50 mg of 10a methoxyagroclavine (60) was dissolved in 50 ml ~-butanol and 50 mg succinic acid added. After stirring 18 hours in the dark, the ~ butanol was evaporated and the residue dissolved in 50 ml H20. This aqueous solution was extracted with CHC1 3 in the usual manner. The CHC1 3 was evaporated and the residue crystallized from acetone/ether to give 20 mg (40%); m.p. l64-l65°C (dec.). TLC, Rf , 0.69 (CD). NMR(CDC1 3): 0.89(3H,t,-CH3); 1.40(4H,m,-CH2CH 2-); 2.53(3H,s, N-CH 3); 3.5992H,m, OCH 2-); 6.35(lH,m, 9 = CH); 6.90-7.23(4H,m, indole); 8.l6J (lH,s, NH). MS: ~/~ = 310(M+)m 267(M-CH 3CH 2CH 2), 238, 167, 154. 10a-methoxyelymoclavine (48). 250 mg. 10a-methoxY-6 8,9_lyser_ galdehyde dissolved in 180 ml EtOH and 100 mg NaBH 4 added slowly with stirring. The mixture was stirred for 15 minutes, diluted with 100 ml of H20 and stirred an additional 5 minutes. The EtOH was evaporated and the residue redissolved in 50 ml H20. This aqueous solution was extracted with CHC1 3. The CHC1 3 was evaporated and the residue crystal lized from acetone to give 110 mg (44%) of pure 10a-methoxyelymoclav;ne; mr 217-219°C (dec.) (lit. 219-2210C). TLC, Rf , 0.20 (CE). NMR(DMSO ~): 2.39(3H,s, N-CH 3); 3.00(3H,s, OCH 3); 3,96(2H,d, 17-CH20-); 4.93 78

(lH,s,-OH); 6.57(lH,m, 9 - CH); 7.02(4H,m, indole); 10.68(lh,s, NH).

MS: B/e = 284(M+), 269(M-CH3), 254(M-CH 30), 252, 167, 154. 8-methoxy-6-methyl-8-hydroxymethyl-6 9,10-ergo1ine (69). 50 mg of the 10a-methoxye1ymoclavine were dissolved in 25 ml MeOH and 50 mg succinic acid added. This solution was stirred in the dark for 12 hours after which the MeOH was evaporated. The residue was dissolved in 50 m1 H20 and extracted with CHC1 3 in the usual manner. The CHC1 3 was evaporated and the residue crystallized from acetone to give 20 mg (40%); m.p. 167-170°C(dec). TLC, Rf , 0.53 (CD). NMR(DMSO-~): 2.39(3H,s, N-CH 3); 3.00(3H,s, OCH 3); 3.95(2H,d, 17-CH20); 4.90(lH,s, OH); 6.56(lH,m, 9 = CH 2); 7.06(4H,m, indole); 10.68(lH,s, NH). MS: ~/~ = 284 (M+), 254(M-CH 30), 252, 167, 154. Solvomercuration-demercuration. The clavine alkaloids lysergene, lysergine, lysergo1, agroc1avine, and elymoclavine were reacted with 60 Hg(OAc)2 according to Bernardi ' s procedure. 10 mg of the alkaloid was dissolved in 3 m1 of MeOH. A solution of 14 mg Hg(OAc12 in 2 m1 MeOH was then added dropwise with stirring. The mixture turned light green and was stirred at room temperature for 8 hours. After 8 hours some elemental Hg had separated. The reaction mixture was cooled to O°C and made basic (-pH 10) with conc. NaOH. A solution of 15 mg

NaBH 4 in 5 m1 MeOH was then added slowly with stirring. After 5 minutes the reaction was diluted with ice water and extracted with

CHC1 3. The CHC1 3 extracts were concentrated and examined by TLC. None of the above alkaloids yielded the expected methoxy ethers. The reaction products in all cases appeared to be mixtures of unreacted starting material, rearrangement products, and dihydroderivatives. 79

A modification of the above procedure was tried with lysergene and lysergine. Four hours after the addition of the Hg(OAc)2 2 ml of a saturated NaCl solution were added in an effort to form the HgCl complex and facilitate isolation of a product. After another 2 hours, the reaction mixture was reduced with NaBH 4 as above. This procedure was also not successful in that only the unreacted starting "alkaloids were seen on TLC. Attempted reduction of lOa-methoxy-6 8,9-lysergaldehyde (56) to 10 -methoxyagroclavine (60). The thioacetal was prepared with ethanedi thiol. 200 mg of 10a-methoxy-6 8,9-lysergaldehyde (56) was dissolved in 2 ml ethanedithiol. 10 mg of £-toluenesulfonic acid was added and the reaction mixture stirred for 4 hours. The product was precipitated with ether and filtered. The precipitate was dissolved in a 1% aque ous tartaric acid solution, made alkaline, and extracted with CHC1 3 and CHC1 3/iso-propanol (3:1). About 180 mg of a yellow powder were recovered from the extraction. MS: ~/~ = 358 (M+). The crude product from the above reaction was placed in a 100 ml round bottom flask. About 2 9 of Raney Nickel was added with 50 ml EtOH. This mixture was refluxed for 48 hours. The reaction mixture was filtered and washed with EtOH. The filtrate was then evaporated, dissolved in 1% acqueous tartaric acid solution, made alkaline, and extracted with CHC1 3. TLC examination showed no lOa-methoxy-agro clavine was produced. Instead, the major product of the reduction appeared to be identical to lysergene (25). 80

Synthesis of Lysergic Acid Amides 10a-methoxy-6 8,9-lysergic acid amide (70). 100 ml of iso propanol was saturated with NH3 at O°C. 1.15 g KCN was added and the mixture stirred for 10 minutes. 1.0 g 10a-methoxy6 8,91ysergaldehyde (56) was then added and stirred for an additional 10 minutes. 10 g of very active Mn0 2 (Fatiadi) were then added slowly with vigorous stirring and the mixture stirred at O°C for 6 hours. The Mn02 was removed by filtration and the filtrate evaporated to dryness. The residue was dissolved in CHC1 3 and washed with half saturated aqueous sodium bicarbonate solution. The aqueous washings were then made basic (pH 11) with NH 40H and washed with CHC1 3. The CHC1 3 washings were combined with the original CHC1 3 solution, dried over Na 2S04 and evaporated to dryness to give .700 g (66%) of 10a-methoxy-6 8,9_ lysergic acid amide. This crude product was used in the following reduction. An analytical sample was obtained by precipitation from ethyl acetate with diethyl ether followed by crystallization from isopropanol. mp 140-143°C (dec). TLC, Rf 0.15 (CE). NMR (DMSO-~): 2.38 (3H,s, N-CH 3); 3.00 (3H,s, OcH 3); 7.00-7.19 (4H,m, indole); 7 . 45 (1 H, m, 9 = CH); 10 . 72 (1 H, s, NH) . MS : ~/~ = 297 (M+), 267

(M-CH 30), 249, 224, 221, 207, 196,180,167,154. Lysergic acid amide (71)/isolysergic acid amide (72). 50 ml glacial acetic acid were added to a mixture of 500 mg crude 10a methoxY-6 8,9-lysergic acid amide (Z2) and 12.5 g zinc dust in a laO m1 round bottom flask. After stirring 18 hours at room temperature, the Zn dust was filtered off and washed with H20. The acid filtrate 81 was diluted with ice water and neutralized slowly with NH 40H. The solution was kept cold with added ice. The basic mixture was then extracted with CHC1 3. The CHC1 3 was evaporated and the residue chroma tographed on a florisil column (34 f). The column was eluted with

CHC1 3 followed by 5% MeOH in CHC1 3. The 5% MeOH/CHC1 3 eluate contained 100 mg of a relatively pure mixture of the lysergic acid ami des. The two isomers were separated by preparative layer TLC to give 15 mg of lysergic acid amide (3%) and 25 mg isolysergic acid amide (5%). The TLC pure products could not be crystallized. Lysergic acid amide: mp 95-98°C (dec) (lit. 115°C). TLC, rf , 0.12 (CD). Isolysergic acid amide: mp l35-l40°C (dec.). TLC, Rf , 0.40 (CE). IR, NMR, and MS of both compounds were identical to the published data. 10a-methoxy-~ 8,9-lysergic acid piperidine amide (73). .500 9 piperidine in 100 ml isopropanol were cooled to O°C and made slightly basic with 2 drops NH 40H. 1.15 9 KCN was added and the mixture stir red for 10 minutes after which 1.0 g 10a-methoxy-~ 8,9-lysergaldehyde (56) was added. This solution was stirred for another 10 minutes after which 10 9 of very active Mn0 2 (fatiadi) were added slowly with vigorous stirring. This mixture was stirred at O°C for 6 hours after which the Mn0 2 was removed by filtration, washed with MeOH, and the filtrate evaporated to dryness. The residue was dissolved in CHC1 3 and washed with half saturated aqueous sodium bicarbonate solution. The aqueous washings were then made basic (pH 11) and washed with

CHC1 3. The combined CHC1 3 solutions were evaporated to dryness to give 900 mg (705) of 10a-methoxy-~ 8,9-lysergic acid piperidine amide. 82

This crude product was used in the following reduction. An analytical sample was prepared by precipitation from ethyl acetate with diethy1 ether followed by crystallization from isopropanol/ether; mp 129-131°C

(dec) TLC, Rf , 0.60 (CE), NMR(CDC1 3): 1.66 (6H,m, piperidine-CH2-); 2.50 (3H,s, N-CH 3); 3.20 (3H,s, O-CH 3); 3.50 (4H,m, piperidine N-CH 2-); 6.72 (lH,m, 9 = CH 2); 6.90-731 (4H,m, indole); 8.51 (lH,s, NH). MS: ~/~ = 365 (M+), 33.5 (M+-CH 30), 333, 248, 221, 207, 196, 180, 167, 154. Lysergic acid piperidine amide (74)/iso1ysergic acid piperidine amide (750). 50 ml glacial acetic acid were added to a mixture of 500 mg 10a-methoxy-~ 8,9-1ysergic acid piperidine amide (73) and 12.5 g zinc dust. The mixture was stirred 18 hours at room temperature after which the Zn dust was removed by filtration and washed with H20. The acidic filtrate was diluted with ice water and neutralized with NH 40H. The solution was kept cold with added ice. The basic mixture was then extracted with CHC1 3. The CHC1 3 was dried over Na 2S04 and evaporated and the residue chomotographed on a florisil column. The column was eluted with CHC1 3 followed by 5% MeOH in CHC1 3. The 5% MeOH/CHC1 3 eluate contained 150 mg of a relatively pure mixture of the two iso meric piperidine ami des. These were separated by preparative layer TLC to give 60 mg of lysergic acid piperidine amide (13%) and 100 mg of isolysergic acid piperidine amide (22%). The TLC pure products could not be crystallized. TLC, R , 0.1/.48 (CE). NMR (CDC1 ): f 3 1.76 (6H,m, piperidine-CH2-); 2.79 (3H,s, N-CH 3); 3.55 (4H,m, piperi dino-N-CH2-); 6.72 (lH,m, 9 = CH); 6.90-7.30 (4H,m, indole). MS: !!!I e = 335 (~1+ ) . 10 -methoxy- 8,9-lysergic acid-L-2-amino-l-propanol amide (76). 83 .500 g L-2-amino-l-propanol in 100 ml isopropanol were cooled to o°C and made slightly alkaline with 2 drops NH 40H. 1.15 g KCN was added and the mixture stirred for 10 minutes after which 1.0 g 10a-methoxy- 6 8,9-lysergaldehyde (56) was added. This solution was stirred another

10 minutes after which 10 g of every active Mn0 2 (Fatiadi) were added slowly with vigorous stirring. This mixture was stirred at O°C for

3 hours and then at room temperature overnight. The Mn0 2 was removed by filtration, washed with MeOH and the filtrate evaporated to dry ness. The residue was dissolved in CHC1 3 and washed with half satu rated aqueous bicarbonate solution. The aqueous washings were made basic with NH 40H and washed with CHC1 3" The combined CHC1 3 solutions were evaporated to dryness to give 600 mg (48%) of crude lOa-methoxy- 6 8,9-lysergic acid-L-2-amino-l-propanol amide. This crude product was used in the following reduction. Attempts to purify and crystal lize the product resulted in decomposition. Chromatography on silica gel and elution with 5% MeOH in CHC1 3 gave a relatively pure non crystalline product which gave a suitable mass spectrum. MS: m/~ =

355(M+), 325 (M+-CH 30), 307, 267, 221, 207, 196, 181, 167, 154. Ergonovine (77)/ergonovinine (78). 50 ml glacial acetic acid were added to a mixture of 500 mg 10a-methoxy-6 8,9-lysergic acid-L-2- amino-l-propanol amide and 12.5 g zinc dust. The mixture was stirred at room temperature for 18 hours after which the zinc dust was removed by filtration and washed with H20. The acidic filtrate was dilu~ed with ice water and neutralized with NH 40H. The solution was kept cold by adding ice. The basic mixture was then extracted with CHC'3' These extracts were dried and evaporated to give 200 mg of a complex residue. 84 Approximately 15 Ehrlich's positive compounds were seen on TLC along with what appeared to be small amounts of the fluorescent ergonovine and ergonovinine. Attempts to isolate and purify these two products by PLC gave 2 mg of a still impure mixture. These two products were identical to ergonovine and ergonovinine standards on TLC in the CE, CEA, and EED solvent systems. Attempted oxidation of elymoclavine (55) and agroclavine (68) with selenium dioxide. 20 mg of alkaloid and 10 mg Se02 were refluxed in various solvents for 5 hours. The reactions run in methanol, methanol/acetic acid, methanol/water, and dioxane showed no reaction after 5 hours other than decomposition. Both elymoclavine and agro clavine showed some reaction in glacial acetic acid at 100°C. The yield looked poor, however, on TLC and extensive decomposition was also occurring. Attempts to isolate the product by preparative TLC were unsuccessful. REFERENCES

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Name Brian Lee Thompson Birthdate June 13, 1950 Education University of Southern California 1968-1969 Los Angeles, California 1969-1972 Brigham Young University Provo, Utah Degree B. S., Chemi stry 1972 Brigham Young University Provo, Utah Professional Organizations American Chemical Society American Society of Pharmacognosy Publication T-C. Choong, B. L. Thompson and H. R. Smitb, IISynthesis of 10a methoxy-~ 8,9-lysergaldehyde from El ymoc 1a vi ne, II Journa 1 of Pharm.Science, 66, 1340 (1977).