This dissertation has been 65-9359 microfilmed exactly as received

KARNES, Harold AUen, 1938- THE SYNTHESES OF INTRAMOluECULARLY OVERCROWDED COMPOUNDS.

The Ohio State University, Ph.D., 1965 Chemistry, organic

University Microfilms, Inc., Ann Arbor, Michigan THE SYNTHESES OF INTRAMOLECULARLY OVERCROWDED COMPOUNDS

DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University

by

Harold Allen Karnes, B.A,, M.Sc.

The Ohio State University 1965

Approved by

\a Ia A F W [ M ^ Adviser Department of Chemistry ACKNOWLEDGMENTS

The author wishes to express his appreciation to Dr. Melvin S. Newman for suggesting these problems and for his interest and guidance during the course of their development. The author also wishes to thank his wife for her aid and encouragement during the course of this research.

ii VITA

November 28, 1938 Born— Williamsburg, Ohio 1980# ##**## B.A., Earlham College, Richmond, Ind. 1960-1962 .... Teaching Assistant, Department of Chemistry, The Ohio State University Columbus, Ohio 1962 ...... M.Sc., The Ohio State University, Columbus, Ohio 1963-1964 . . . . Research Assistant, Department of Chemistry, The Ohio State University, Columbus, Ohio

PUBLICATIONS "Syntheses of the Three Isomeric Diethyl- and Dineopentyl- tetramethylbenzenes," M. S. Newman, J. R. LeBlanc, H. A. Karnes and G. Axelrad, J. Am. Chem. Soc., ^86, 868 (1964)

FIELDS OF STUDY

Major Field; Organic Chemistry

iii CONTENTS

Page ACKNOWLEDGMENTS ...... ii VITA...... iii ILLUSTRATIONS .'...... vi INTRODUCTION I. Statement of problems...... 1 II. Discussion of buttressing effect .... 1 III. Discussion of aromatic molecular complexes. 7 ' SYNTHETIC ROUTES ...... 12 RESULTS AND DISCUSSION ...... 16 I. Syntheses of 3,4,5,6- and 2,4,5,7- tetramethyIphenanthrene...... 16 II. Syntheses of the 9,10-quinones of 3,4,5, 6- and 2,4,5,7-tetramethylphenanthrene . 23 III. Preparation of 4,5-dimethylphenanthrene. 24 IV. Preparations of the 9,10-quinones of 2,7- and 4,5-dimethylphenanthrene . . . 25 V. Synthesis of o-dineopentyltetramethyl- . ...... 26 EXPERIMENTAL

I. Generalizations...... 29

II. Synthesis of 3,4,5,6-tetramethyl­ ...... 30 III. Synthesis of 2,4,5, 7-tetraumethyl- - phenanthrene...... 39

iv CONTENTS

Page

IV. Synthesis of 3,4,5,6-tetramethyl-9,10- phenanthrenequinone...... 48 V. Synthesis of 2,4,5,7-tetramethy1-9,10- phenanthrenequinone» 50 VI. 4,5,-Dimethylphenanthrene ...... 52 VII. 4,5-Dimethyl-9,10-phenanthrenequinone . 54 VIII. 2,7 Dimethyl-9,10- phenanthrenequinone . 54 IX. Synthesis of o-Dineopentyltetra- methylbenzene ...... 56 ILLUSTRATIONS

FIGURES

Figure Page 1. Nuclear Magnetic Resonance Spectrum of 3.4.5.6-Tetrame thylphenanthrene...... 38 2e Nuclear Magnetic Resonance Spectrum of 3,4,-Dimethyl-4H-cyclopenta def phenanthrene ...... 39 3. Nuclear Magnetic Resonance Spectrum of 2.4.5.7-Tetramethylphenanthrene...... 46 4. Nuclear Magnetic Resonance Spectrum of o-Dineopentyl te trame thylbenzene...... 62

Table I Chromatographic Purification of 2,4,5,7- Te trame thylphenanthrene...... 45

vi INTRODUCTION

I. Statement of problems This dissertation concerns two separate synthetic problems.. One problem involves the synthesis of 3,4,5,6- and 2,4,5,7-tetramethylphenanthrene, the corresponding 9,10-quinones of these and the 9,10-quinones of 2,7- and 4,5-dimethylphenanthrene. The syntheses of these compounds were undertaken in order that information concerning the buttressing effect might be gained. The other problem involves the synthesis of ortho- dineopentyltetramethylbenzene in order that information concerning the nature of charge transfer complexes in­ volving aromatic could be gained.

II. Discussion of buttressing effect One of the first observations of the buttressing effect was made by Chien and Adams who measured the rates of racemization of a series of optically active biphenyls derived from 2-nitro-6-carboxy-2’-methoxy-biphenyl.^

1 S. L. Chien and R. Adams, J. Am. Chem. Soc. 56, 1787 (1934). 1 These workers observed that single substituents in the 3' position exerted a large retarding effect on the rate of racemization. Similiar substituents in the 5* position exerted only a small retarding effect on the rate. Westheimer later explained these observations by attributing the rate retardation caused by the 3' substituents to their blocking or buttressing of the methoxyl group in the 2' position. Thus the 2* methoxyl group is more effective in 2 preventing rotation about 1,1' bond. Westheimer thus termed the effect observed by Adams and Chien as the buttressing effect. In order to gain more information on the buttressing effect Rieger and Westheimer synthesized, resolved, and measured the rates of racemization of 2,2'- diiodo-5,5'-dicarboxybiphenyl and 2,2',3,3'-tetraiodo- 2 5,5'-dicarboxybiphenyl. The diiodo acid was found to

racemize 30,000 times faster than the tetraiodo acid. The activation energy for the tetraiodo acid exceeded that for the diiodo by about 6.4 kcal mole which is an indication of

Rieger and P. Westheimer, J. Am. Chem,Soc. 19 (1950). the buttressing effect of the meta iodine atoms. Another area in which the buttressing effect has been noted is in the association of di-ortho-substituted phenols. It is well known that the association of di-ortho-substi- tuted phenols is markedly reduced because the ortho substi­ tuents hinder intermolecular H-bonding. Sears and Kitchen showed that the association is further diminished when substituents are also in the meta positions of di-ortho- substituted phenols because the meta substituents prevent 3 the ortho groups from bending back to allow association. The buttressing effect has also been noted in spectral studies of substituted acetophenones. Forbes and Mueller observed that substitution of two ortho-methyl groups in 4 acetophenone produced a marked decrease in absorption. When the two ortho methyl groups were buttressed by two meta methyl groups a further decrease in absorption was observed. This further decrease in absorption was ex­ plained by the fact that the meta methyl groups prevented the ortho methyl groups from bending back away from the COCH^ group and thereby produce greater strain in the

Sears and L. Kitchen, J. Am. Chem. Soc. 71, 4110 (1949). ^W. Forbes and W. Mueller, Can. J. Chem. 33, 1145 (1955). excited state for the polar resonance structure:

Margrave and Newman have observed a buttressing effect in studies of the heats of combustion of several intramo- 5 lecular overcrowded hydrocarbons. These workers found that the difference in heats of combustion of 2,7- and 4,5- dimethylphenanthrene was 12.5± 1.5 kcal/mole.

01

GE

CH,

They called this difference the standard value for steric strain due to intramolecular overcrowding. The difference in the heats of combustion of 3' ,6- and 1',9-dimethyl- benanthracene (15.0±.7 kcal/mole) was found by these work­ ers to be greater than the standard value by approximately 2.4 kcal/mole.

5m . Frisch, C, Barker, J. Margrave and M. Newman J. Am. Chem. Soc. 85, 2356 (1963). • 5 CH, CH, CH, OIOIO OH,

This result was explained as being due to the buttressing effect of the fused ring on the 9-. It was also pointed out that the buttressing effect of a fused ring should approximate that of a methyl group since the steric effect of an adjacent fused ring on a function is about the same as the effect of a methyl group located in the same position.® Prom these results the buttressing effect of a methyl group might be expected to be approxi­ mately 2.4 kcal/mole. In order to obtain further values for the magnitude of the strain involved in the buttressing effect of methyl groups the syntheses of 3,4,5,6-and 2,4,5,7-tetramethyl- phenanthrene, Xa. and Xb. were undertaken.

CH,

CH, CH,

CH, CH,

CH,

Xa Xb

(a) M. S. Newman and C. D, McCleary, J. Am. Chem. Soc, 63, 1537 (1941). (b.) J. Packer, J. Vaughan and E. Wong, ibid. 80, 905 (1958). In Xa the interaction of the 4- and 5-methyl groups is buttressed by the methyl groups in the 3—and 6— positions. This buttressing effect should increase the strain in the entire molecule and the increased strain should result in a higher heat of combustion. The difference in the heats of combustion of Xa and the unbuttressed Xb should indicate the 7 magnitude of the buttressing effect of two methyl groups.

As was pointed out earlier in this discussion the buttressing effect has been noted in various physical properties of hindered molecules. It was therefore of interest to attempt to gain further information on the buttressing effect of two methyl groups by the measurement of certain physical properties of suitably buttressed and unbuttressed compounds. Therefore the syntheses of the 9,10-quinones of Xa and Xb were undertaken so that I.R. and U.V. spectra and oxidation-reduction potentials could be obtained.

CH, CH,

CH, ;0 CH.,

CH, CH. 0

CH

This assumption is valid only if the heats of sub­ limation of Xa and Xb are identical. In order to have a quinone system available which would be expected to give standard effects for steric strain due to intramolecular overcrowding the syntheses of the 9,10-quinones of 2,7- and 4,5-dimethylphenanthrene were also undertaken.

CH.

.0 CH,

'0 CH.

III. Discussion of aromatic molecular complexes Aromatic molecular complexes have been known for many years. The majority of these complexes owe their existence to the capacity of aromatic molecules to func­ tion as electron donors by sharing their electrons. An electron acceptor, additively combined with the aromatic nucleus, forms the second component in these complexes. Alkylated , and other poly- nuclear aromatics are typical electron donors which form molecular complexes. Silver ion, iodine, _s-trinitro­ benzene and aluminum bromide are a few examples of many 8 electron deficient substances which may function as electron Q acceptors in these complexes. At the present time, in most aromatic molecular complexes, the electron acceptor is believed to be bonded to the aromatic nucleus by the weak interaction of the filled molecular orbitals of the aromatic nucleus and the vacant orbitals of the acceptor. This type of interaction 9 is usually described by the following Dewar type notation.

In this type of interaction the electron acceptor is believed to lie above the plane and on the sixfold symmetry axis of the ring In the case of only one electron acceptor, silver ion, have structures been suggested in which the electron acceptor is not bonded to the entire system. The inter­ action of silver ion and aromatic nuclei has been described in terms of a resonance hybrid structure similiar to that

(a.) L. J. Andrews, Chem. Rev. 54, 713 (1954). (b.) L. J. Andrews and R. M. Keefer, "Molecular Complexes Organic Chemistry", Holden-Day, Inc. San Francisco,California. ^ M.J.S. Dewar, J. Chem. Soc. 405 (1946). ^^L.J. Andrews and R. M. Keefer, J. Am. Chem. Soc. 72, 4677 (1950). ^^R.S. Mu1liken, ibid., 74, 811 (1952). suggested for complexes formed from silver ion and olefins. 12 In this type of interaction forms of the type

in which the silver ion is located above the plane and on the sixfold symmetry axis of the ring are presumed to con- tribute to the resonance hybrid. 13 Preliminary interpre­ tation of the x-ray diffraction pattern of the solid silver perchlorate-benzene complex indicates that, in the solid complex at least, the silver ion is located away from the symmetry axis above and between two carbons of the aromatic ring.^^ At the present time the x-ray diffraction data of the solid silver perchlorate-benzene complex is the only ex­ perimental evidence in support of the ability of an electron acceptor to complex with only part of an aromatic system. It is reasonable to assume that many electron acceptors which prefer to complex with all six electrons of an aromatic system might,if forced, complex with only two of the electrons. A study of molecular models indicated that if two neopentyl groups were placed ortho on a tetramethylbenzene

*1 p L.J. Andrews and R. M. Keefer, ibid., _71, 3644 (1949) 13H.J. Taufen, M.J. Murray and P.J. Cleveland, ibid., 62, 350 (1941). ^"^R.E. Rundle and J.H. Goring, ibid., 72, 5337 (1950) 10 ring, the t-bu.tyl groups of the neopentyl radicals would have to lie on opposite sides of the plane of the benzene ring. In this configuration one of the methyl groups of each _t-butyl radical would have to lie very close to the sixfold symmetry axis above and below the plane of the benzene ring. These methyl groups should prevent electron acceptors from lying on the sixfold symmetry axis and thereby complexing with all six electrons. The same methyl groups should not prevent electron acceptors from com­ plexing with part of the system by lying away from the symmetry axis above and between two carbons of the aromatic ring. In the corresponding meta and para dineopentyl- tetramethylbenzene the _t-butyl groups can lie on the same side of the benzene ring. Thus, in these molecules the electron acceptor should be cible to lie on the sixfold symmetry axis and complex with all six electrons. The ring methyl groups in these compounds serve two purposes. The ring methyl groups ortho to the neopentyl groups force the _t-butyl groups out of the plane of the ring. The ring methyl groups also increase the electron density of these compounds making them better electron donors. A study of various electron acceptors with £-,m- and 2-dineopentyltetramethyIbenzenes should give some indication of the ability of electron acceptors to complex with only part of an aromatic system. In order to make this study, 11 the synthesis of o^-,ni” and ^-dineopentyltetramethylbenzene was undertaken.

CH^ GH^ OH, PHg-OCCH,),

CH. O / CHp-CCOH,)3/3 GH-,- CH^ GHg-CCCH^)^ GH, GHg-GCGHj)^ GH, GH,

(GH,)^G-GHg GHg-G(GH^)«

OH^ GH^ This dissertation is concerned in part with the synthesis of the ortho isomer. The preparation of the meta and para isomers has been described previously

15 H.A. Karnes,M.S.thesis, Ohio State University, 1952. SYNTHETIC ROUTES The syntheses of 3,4,5,5- and 2,4,5,7-tetramethyl- phenanthrene were accomplished using the following route,

H0-N=C-C=0 N-OH 1 P II ^ CCl^CH

Ila, lib Ilia, Illb

NagOg

OOgH

^OHgOH COOR» ^ yOXL HNOg GHgOH COOR' CgH^OH Rg

IVa, IVb

Vila, Vllb Va, Vb, R ’aH VIb, R'sCgH^

CH CH, CH, Rh/Al CH. CH,

R<

Xa, Xb 12 13

The syntheses of the 9,10-quinones of 3,4,5,6-and 2,4, 5,7-tetramethylphenanthrene were accomplished using the following route developed by Wittig and Zimmerman^

GOOCH, Va, Vb Na OH, GOOCH. CH.

XIa Rn=GH,, R„=H Xlb R^=H, Rg=CH^

The 2,7-and 4,5-dimethyl-9,10-phenanthrenequinones were prepared by direct oxidation of the corresponding dimethylphenanthrenes.

GrO

^ G. Wittig and H. Zimmerman, Chem. Ber. 629 (1953) 14

CH, CE CrO CE

The direct oxidation method was used in these cases rather than the acyloin reaction because a quantity of 2,7-dimethyl­ phenanthrene was available and a quantity of a 4,5-dimethyl­ phenanthrene was prepared by a new route during this work. The new preparation was accomplished by reducing the cyclic oxide of 4,5-phenanthrenedimethanol with lithium aluminum hydride-aluminum chloride. The previously reported method

\2 CE, LiAlH CE. AlCl,

for effecting this conversion involved treatment of the cyclic oxide with red phosphorus and hydrogen iodide. 2 The synthesis of ^-dineopentyltetramethylbenzene was accomplished using the route which was developed in the 3 synthesis of the meta and para isomers.

M. S, Newman and H. S. Whitehouse, J. Am. Chem. Soc. 21, 3564 (1949). 3 See P. N. 15. page 11. 15

CH, R= CH, ■OH.

RH. CHgO, \ R(CHpCl)p — CH^-CH(;COOEt).Q„ HCl ^ XIII

CH, 1 CH, I 5 1 V 2 — R R -CHg-CCCHgOH)^ -CHg-CCCOOEt)^ 2 ^ XV _ XIV

CH^SOgCl CH,

R -CHg-kcHg-O^SCH^)^ J i a ^ R(_GHp-0-CHp) - " - g - XVI XVII GH,ïs)2

R .CHg-CCCH^)^ 4 , XVIII RESULTS AND DISCUSSION

I. Syntheses of 3,4«5,6- and 2,4,5,7- tetramethyIphenanthrene 0 N-OH N-OH ■NH-C-GH II CCl^CH =5-- R: R. la R^=GH^, RgsH Ila, lib Ib R^=H, R^^CH^

The dimethylanilines la and Ib were treated with chloral hydrate and hydroxylamine hydrochloride to give 2,3- dimethylisonitrosoacetanilide (Ila) and 2 ,4-dimethylisonitro- soacetanilide (Ilb) in 87 and 67% crude yield, respectively. The procedure used was developed by greatly modifying the procedure described for the preparation of isonitrosoacet- anilide.^ The lilperature yields for purified Ila and lib 2 prepared using this procedure are 64 and 55% respectively.

0=0 — 0=0 :-H HP Ila, lib 'OH.

Ilia, Illb 1 C. s. Marvel and G. S. Hiers, "Organic Syntheses", John Wiley and Sons, Inc., New York, 1941 Coll. Vol. I, p.327. 2B. Baker, R. Schaub, J. Joseph, P. McEvoy and J. Williams J. Org. Chem. 149-156 (1952). 16 17 The cyclizations of the isonitrosoacetanilicies were effected by an improved procedure involving the use of hydrogen fluoride. Thus, Ila and lib were cyclized with anhydrous hydrogen fluoride to give 6,7-dimethylisatin (Ilia) and 5,7-dimethylisatin (Illb) in 93 and 89% yield, respectively. When purified samples of Ila and lib were cyclized quantitative yields of Ilia and Illb were obtained. The literature yields for Ilia and Illb prepared by cycli- zation of purified Ila and lib with 86% sulfuric acid are 2 5 7 and 91% respectively. When 86% sulfuric acid was used in this laboratory to cyclize crude lib a yield of only 70% of Illb was obtained. In connection with other problems in this laboratory attempts were made to cyclize 2-ethyl- and 2-chloroisonitrosoacetanilide with hydrogen fluoride.

Crude 2-ethylisonitrosoacetanilide yielded 87% of purified 7-ethylisatin. Crude 2-chloroisonitrosoacetanilide was not cyclized with hydrogen fluoride. Therefore, this cycliza- tion method will probably fail in general with deactivated aromatic rings. The use of hydrogen fluoride in this work represents the first report of its use for effecting the cyclization of isonitrosoacetanilides. The dimethylisatins were oxidized by an improved procedure which involved the use of aqueous sodium peroxide. Thus 2-amino-3,4,-dimethyIbenzoic acid (IVa) and 2-amino-3,5- dimethylbenzoic acid (IVb) were prepared in 95 and 98% yield, respectively,. The literature yields for these amino acids 2 are 69 and 65% respectively* In order to obtain these 18 higher yields existing methods for oxidizing isatins were modified and the following procedure was developed. 2 * 3 A dilute solution made by adding two equivalents of sodium hydroxide to one equivalent of 30% hydrogen peroxide was added dropwise to a sodium hydroxide-potassium chloride solution of the isatin at 10-12“ In an experiment in which a solution made by adding one equivalent of sodium hydroxide to one equivalent of 30% hydrogen peroxide was used the yield dropped to 83%. In an experiment in which the sodium peroxide solution was added all at once only a 64% yield was obtained. When no potassium chloride was added cruder product was obtained. At the present time the greater yield from the use of sodium peroxide and the purer products from the use of potassium chloride are unexplained. The increase in yield effected by dropwise addition of the oxidizing agent rather than addition all at once can be explained by postulating that an intermediate in which the carbonyl group ortho to the amino function is destroyed by the addition of some oxidizing agent may^ be formed. In such an intermediate the amino group is not protected from oxidation. Therefore in order to decrease the possibility of oxidation of the amino function it is important to keep . the concentration of the oxidizing agent at a minimum. In an attempt to determine the generality of this oxidation procedure, 7-chloro-, 7-ethyl- and 4,7-dimethyl-

^?riedl"ander XIV p.447. (1921-25). 19 isatins were oxidized. Yields of better than 95% were obtained in the first two cases. However in the case of 4,7-dimethylisatin no amino acid was isolated. This surprising result is unexplained. The dimethylaminobenzoic acids were diazotized and coupled essentially by the procedure described for the preparation of diphenic acid.^ In this manner 5,5',6,6'- tetramethyldiphenic acid (Va) and 4,4',6,6'-tetramethyldi- phenic acid (Vb) were prepared in 55 and 60% yield respectively. The yields of crude product in this reaction were 94 and 82% respectively. The purified diacids were reduced with lithium aluminum hydride to give 2,2*-bis(hydroxymethyl)-5,5'6,6'- tetramethylbiphenyl (Vila) and 2,2'-bis(hydroxymethyl)_4^41^ 6,6'-tetramethylbiphenyl (Vllb) in 90 and 88% yields respectively. It is noteworthy to mention that these excellent results were obtained by the novel procedure of simply adding the solid diacids to a lithium aluminum hydride ether mixture. This procedure was used because of the insolubility of these diacids in ether. In connection with some other work this procedure was used to reduce pseudo ethyl 5-formyl-4-phenanthrenecarboxylate and gave excellent results. A crude batch of the diacid Vb was esterified with ethanol to give diethyl 4,4',6,6'-tetramethyl-diphenate (VIb)

4 E. R. Atkinson and J. J. Lowler, "Organic Syntheses" John Wiley and Sons, Inc., New York, 1946, Coll. Vol. I. p.222 20 in 70% yield. The estérification was carried out mainly as a purification step. The diester VIb was reduced with lithium aluminum hydride to give the dialcohol Vllb in 92% yield. The dialcohols were treated with phosphorus tribromide to give 2,2'-bis(bromomethyl)~5,5',6,6'-tetramethylbiphenyl (Villa) and 2,2'-bis(bromomethyl)-4.4*,6,6'-tetramethyIbi- phenyl(VIIIb) in 90 and 88% yield respectively. The dibromides were coupled with phenyllithium essen­ tially by the procedure described by Oberender for the pre­ paration of 4,5 dimethyl-9,10-dihydrophenanthrene^ to give 3,4,5,6-tetramethyl-9,10-dihydrophenanthrene (IXa) and 2,4, 5,7-tetramethyl-9,10-dihydrophenanthrene (IXb) in 83 and 85% yield, respectively. These results support Oberender's find­ ings that the addition of the dibromide to a phenyllithium solution results in higher yields than the previously re­ ported procedures^ of adding the phenyllithium solution to the dibromide. In this work it was found that Oberender's procedure was improved by doubling the amount of phenyl­ lithium. The dihydrophenanthrenes were dehydrogenated by a hydrogen transfer reaction with benzene and rhodium on

C P. G. Oberender, Ph.D. dissertation, Pennsylvania, State University, 1960. ^G. Wittig and H. Zimmerman, Ber., _8j5, 62S' (1953). 7 M. S. Newman and D. Lednicer, J. Am. Chem. Soc. 78, 4765 (1956). 7 21 alumina at 300® to give 3,4,5,6-tetramethylphenananthrene (Xa) and 2,4,5,7-tetramethylphenanthrene (Xb) in 42 and 24% yield, respectively. In this manner 9 g, samples of by g.l.c. better than 99% pure Xa and Xb were prepared. The crude yields by g.l.c. were 51 and 45%, respectively. In the case of Xa a mixture of essentially only starting material and product was obtained. The mixture could be separated very efficiently by chromatography aoid the efficiency is represented in the yield of purified product. In the case of Xb, however, a mixture containing starting material, product and significant amounts of two impurities was isolated. The product could be readily separated from the starting material and one of the impurities by chromatography. The separation of Xb from the other impurity, was effected by recrystallization but only with great loss which is re­ flected in the low yield of purified product. Attempts to purify Xb by picrate formation failed. The two impurities formed in the conversion of IXb to Xb were never isolated in sufficient purity to allow identification. At the present time these impurities are believed to be a 9,10 Q dihydrotrimethylphenanthrene and a trimethylphenanthrene. The hydrogen transfer reaction was used to accomplish the aromatization rather than methods involving heating with palladium on charcoal or sulfur because isolation and re-

Q The loss of alkyl groups in aromatizations with palladium on carbon have been reported. W. Cocker, B. Cross, J. Edwards, 0. Jenkinson and J. McCormick, J. Chem. Soc. 2355 (1953). 22 use of unreacted starting material was possible. In most runs 30-50% of unreacted starting material could be re­ covered.

The reaction was found to be very dependent upon temperature. When temperatures less than 285® were used yields of less than 20% were obtained. In the case of Xa when temperatures of greater than 310® were used large amounts of an impurity identified by its n.m.r. as 3,5- dimethyl-4H-cyclopenta ^def phenanthrene were isolated.

GH, CH.

Significant amounts of this material were also obtained when attempts were made to increase the yield of Xa by re­ cycling the crude product with fresh catalyst. The structures of Xa and Xb were supported by their nuclear magnetic resonance spectra and mass spectra. 9 The mass spectra of both Xa and Xb showed trace amounts of a material with a mass peak of 218. This material was identi­ fied in the case of Xa as 3,5-dimethyl-4H -cyclopenta j^def^ phenanthrene. The material with m/e of 218 in Xb was assumed to be the analogous 2,6-dimethyl-4H-cyclopenta |defj phenan­ threne. When the mass spectra samples were analysed with

9 Our thanks to Dr. Mynard Hamming of Continental Oil Co., Ponca City, Oklahoma, for determining and interpreting the mass spectra of these compounoo. 23 n.m.r. and g.l.c. no impurities were detected. Therefore it was assumed that trace amounts of the dimethylcyclopenta- phenanthrenes were being formed during vaporization in the mass spectral determination. It was later shown by g.l.c. that upon heating at 360-365* for 45 minutes Xa yielded 25% 3,5-dimethyl-4H-cyclopenta j^ef^ phenanthrene. When Xb was heated at 360-365® for 45 minutes the recovered material contained 97% by g.l.c. Xb. and 3% of an impurity. This impurity, on the basis of it relative g.l.c. retention time, is not believed to be 2,6-dimethyl-4H-cyclopenta j^def J phenanthrene. The difference in the thermal stability of Xa and Xb might be attributed to the buttressing effect.

II. Syntheses of the 9.10 quinones of '3,4,5 ,6-and 2,4,5,7- tetramethylphenanthrene In order to prepare the necessary diesters the crude diacids Va and vb were esterified with methanol to give dimethyl 5,5',6,6'-tetramethyldiphenate (XIa) and 4,4',6,6'- tetramethyldiphenate (Xlb) in 73 and 61% yield, respectively. The diester XIa was converted to 3,4,5,6-tetramethyl- 9,10-phenanthrenequinone (Xlla) in 38% yield by treatment with sodium in refluxing . By this method 3 g. of Xlla was prepared. When the same procedure was applied to Xlb only crude starting material could be isolated. The diester Xlb was, however, converted to 2,4,5,7-tetramethyl-9, 10-phenanthrenequinone (Xllb) in 45% yield by treatment with sodium at 150-160® in a P -cymene-xylene mixture. In this way 4 g. of Xllb was prepared. When the reaction of XIa with sodium was carried out in xylene-j^-cymene at 145-150" no quinone. and no starting material was isolated. In both reactions unidentified base soluble materials were isolated in yields of 10-80%. These materials axe believed to arise from further reaction of the quinones with sodium or sodium methoxide. The I.R. of the base soluble materials showed no phenolic OH band.

III. Preparation of 4,5-dimethylphenanthrene

GH OH, LiAlH .OH Aid, OH,

The cyclic oxide of 4,5-phenanthrenedimethanol was reduced as illustrated to give 4,5-dimethylphenanthrene in 2 7% yield. By this method 10 g. of better than 99% pure 4,5-dimethylphenanthrene was prepared. The crude product (66%) of this reduction contained 54% 4,5-dimethyl­ phenanthrene, 42% dihydropyrene and 4% 4,5-dimethyl— 9,10- dihydrophenanthrene as determined by g.l.c. This mixture was purified by converting the dihydropyrene to and separating the resulting mixture by chromatography. The conversion of the dihydropyrene to pyrene was accomplished by heating the crude product in a xylene-camphene mixture with 5% palladium on charcoal. The camphene was used to 25 prevent a hydrogen transfer reaction between the dihydropyrene and the 4,5-dimethylphenanthrene. When no camphene was used approximately 18% of the 4,5- dimethylphenanthrene was converted to 4,5-dimethyl-9-10- dihydrophenanthrehe. The activity of the catalyst produced in the dehydrogenation of dihydropyrene is note­ worthy. The reduction of the cyclic oxide was found to be very dependent on temperature and time. Temperatures of better than 60“ and reaction times of better thain 24 hours were necessary to effect this reduction. These conditions are similar to the conditions which are reported for the 9 reduction of benzyl alcohol. It is believed that this work represents the first report of the successful reduction of a non-activated benzylic ether with lithium aluminum hydride aluminum chloride.

IV, Preparations of the 9,10-quinones of 2,7-and 4,5-dimethyl- phenanthrene. These quinones were synthesized by the chromium trioxide oxidation of the dimethylphenanthrenes. Thus, 2,7-and 4,5-

9J. Brewster, H. Bayer and S. Osman, J. Org. Chem. 29, 110 (1964). ^^B. R. Brown and G. A. Somerfield, Proc. Chem. Soc. 2? 72 (1958) found that 4 ’-methoxylflavan was reduced by LiAlH^- AlClg but flavan was not reduced. 25 dimethylphenanthrene were treated with chromium trioxide in acetic acid to give 2,7-dimethyl-9,10-phenanthrenequinone and 4 ^5-dimethyl-9 , 10 -phenanthrenequinone in 42 and 27% yield, respectively. • In the oxidation of 2,7-dimethylphenanthrene a 17% yield of 2,7-dimethyl-l,4-phenanthrenequinone was isolated.

GH, .CH

V. Synthesis of o-dineopentyl- tetramethyIbenzene This synthesis was accomplished as illustrated in the synthetic route section. was chloromethylated to give bis-chloromothyl- prehnitene (XIII) in 70% yield. This step was the most difficult encountered in the synthetic sequence. Known chlorométhylation procedures'^ which worked well in the bis-chloromethylation of and isodurene failed to give

any XIII. The reaction was finally effected by using temperatures of 105-108°. Bis-chloromethylprehnitene was condensed with diethyl methylmalonate to give 1,2-bis(2,2-dicarbethoxypropyl)preh- nitene(XIV) in 91% yield. The tetraester XIV was reduced by lithium aluminum

Rhoad and P. Plory, J. Am. Chem. Soc. 72, 2216 (1950). ■ 27 hydride to give 1,2- |^2,2-bis (hydroxymethyl ) propyl J preh- nitene(XV) in 81% yield. The tetraalcohol XV was mesylated to give the tetra- methanesulfonate of 1,2-bis j^2,2-bis (hydroxymethyl ) propyl J prehnitene(XVI) in 95% yield.

The tetramethanesulfonate XVI was converted to 1,2- bis(3-methyl-3-thietanyl)methylprehnitene(XVII) by treat­ ment with sodium sulfide in 60% yield. The thietanyl compound XVII was reduced by W-2 Raney nickel to give ^-dineopentyltetramethyIbenzene(XVIII) in 86% yield. A total of 15 g. of XVIII was prepared. The structure of XVIII was supported by its mass spectrum and n.m.r. spectrum. The n.m.r. of XVIII showed an unexpected doublet at 7.12 which was assigned to the benzylic hydrogens of the neopentyl groups. The n.m.r. of meta- and para-dineopentyltetramethyIbenzene showed only singlets at 7.23 and 7.25Trespectively for the benzylic hydrogens of the neopentyl groups. When the n.m.r. of XVIII was run at 60“ only a singlet was observed for the same benzylic hydrogens. When the n.m.r. was run at -10“ a quartet appeared. A study of a molecular model of XVIII indicates that rotation around the phenyl-methylene bond in each neopentyl group is restricted by the interaction of the _t-butyl groups. In the least hindered conformation one of the methylene hydrogens of each neopentyl group lies in the plane of the benzene ring and the other hydrogen 28 lies out of the plane. Thus the two hydrogens are different and one would expect a quartet in the n.m.r. The fact that a doublet is observed at room temperature indicates that at this temperature the restriction in rotation is sufficient to cause only a very slight difference in the benzylic hydrogens. EXPERIMENTAL

I. Generalizations All melting points were uncorrected. The melting points of all intermediates were taken on a Pisher-Johns Melting Point Apparatus. The melting points of the final products were determined in an oil bath using National Bureau of Standards calibrated thermometers. Microanalyses were done by Galbraith Microanalytical Laboratories, Knoxville, Tennessee. The phrase, "treated in the usual manner," used throughout this section means that the organic solvent layer was washed successively with water, saturated sodium chloride solution, filtered tbrought anhydrous magnesium sulfate and the solvent distilled under reduced pressure. Alcoa chromatographic alumina activated by heating 24 hr. at 220® was used for chromatography unless stated otherwise. Gas liquid chromatographic analyses were run on a P. and M. model 609 flame ionization instrument. A two- foot 10% silicone rubber column was used at 200-220®. The values obtained by this method were not calibrated.

29 30 II. Synthesis of 3,4,5,6-tetramethyl- phenanthrene 2,3-Dimethyl-isonitrosoacetanilide (Ila). In a two- gallon enamel pail equipped with stirrer and thermometer were placed 4 1. of water, 145,5 g. (0.88 moles) of chloral hydrate, 176.0 g. (2,55 moles) of hydroxylamine hydrochloride in 1 1. of water, 1136 g. of anhydrous sodium sulfate, and a solution of 96.8 g. (0.88 mole) of freshly distilled 2,3- dimethylaniline (Aldrich) dissolved in 800 ml. of water con­ taining 88.0 g. of concentrated hydrochloric acid. The re­ sulting thick white mixture was heated over a 1 hr. period to 53*. The resulting light brown mixture was then held at 53“ for 1.5 hr. and at 60“ for 1 hr. To the resulting brown mixture was then added 20.0 g. (0.12 mole) of chloral hydrate and 20.0 g. (0.29 mole) of hydroxylamine hydro­ chloride. The mixture was heated 1 hr. at 62-65“, cooled to room temperature and filtered. The light brown solid was washed with 2 1. of water and dried at 70“ to yield 116.0 g. (75.8%) of Ila., m.p. 124-126“ (lit. m.p. 131-132“).^ The filtrate and wash water were placed in the reaction bucket and 36.0 g. (0.22 mole) of chloral hydrate and 360 g. (0.52 mole) of hydroxlyamine hydrochloride added. The resulting mixture was heated to 80“ during 1 hr. and allowed to cool. The resulting light yellow solid was filtered, washed with 500 ml. of water and dried at 70“ to yield an additional 19. 0 g. (12.4%) of Ila., m.p. 122-125“. The total yield was

^B. Baker, R. Schaub, J. Joseph, P. McEvoy, and J. Williams, J. Org. Chem. rz, 149. (1952). 31 135g. (88.2%).

6J7-Dimethylisatin (Illa). To 1.4 1. of anhydrous hydrogen fluoride in a 2-1, polyethylene bottle was added in small portions 116.0 g. (0.50 mole) of crude Ila. The resulting solution was allowed to evaporate to dryness and 400 ml. of a 4N sulfuric acid was added. The resulting mixture was warmed on a steam bath, filtered and the resulting red solid washed with 500 ml. of water. The crude product was treated with 900 ml. of water containing 40.0 g. of sodium hydroxide. The dark mixture was heated to 80“ and filtered through Hyflo Super-cel..2 The dark filtrate was cooled and acidified dropwise with 18% hydrochloric acid until a brown precipitate appeared. The resulting mixture was treated with an additional 10 ml. of 18% hydrochloric acid and filtered through Hyflo-Super-Cel. The dark filtrate was acidified with 200 ml. of 18% hydrochloric acid and filtered. The resulting orange solid was washed with 1.1. of water and dried at 80® to yield 98,0 g. (93%) of orange Ilia., m.p.255-258®. (lit. m.p.252®).^

^Hyflo Super-Cel is an inert cellulose filtering aid.

^German Pat. 514,595®, C. A., _2§.* 2157 (1931). 32 2-Amlno-3,4-dimethylbenzoic Acid (IVa). In a 1-1. flask equipped with magnetic stirrer, thermometer and addition funnel were placed 40.0 g. (0.23 mole) of Ilia, and 200 ml. of water containing 10.0 g. (0.24 mole) of sodium hydroxide. After heating until all of IVa dis­ solved, 250 ml. of water and 40.0 g. of potassium chloride were added. The resulting solution was cooled to 12“ and treated dropwise at 11-12“ during 1 hr. with 44.0 g. (0.39 mole) of 30% hydrogen peroxide dissolved in 400 ml. of cold water containing 35.0 g. (0.90 mole) of sodium hydroxide. The solution was then stirred ^ hr. without external cool­ ing. Dropwise addition of 90 ml. of acetic acid précipitât- , ed a cream-colored solid which was filtered, washed with 300 ml. of water, and dried at 80“ to yield 36.0 g. (95.7%) of IVa., m.p. 180-184“ (lit. m.p. 184-186“).^ Other runs using essentially the same procedure.gave yields of 90-95%. In a run identical to the run described except that the hydrogen peroxide was dissolved in 400 ml. of water containing 0.45 mole of sodium hydroxide a yield

of only 83% was obtained. In some cases the crude product was purified by treat­ ment with concentrated hydrochloric acid. The resulting fairly insoluble hydrochloric acid salt was leached with acetone, dissolved in dilute sodium hydroxide and the free amino acid regenerated by acidification with acetic acid. In this manner white IVa., m.p. 181-183® was isolated with

little loss. 33 5,5'T6,6'-Tetramethyldiphenic Acid (Va). In a 1-1. flask were placed 74.1 g. (0.45 mole) of purified IVa and 750 ml. of water containing 24.0 g. of sodium hydroxide. After heating until all the solid dissolved 31.8 g (0.46 mole) of Sodium nitrite was added. The resulting solution was cooled to 10® and added in small portions to a stirred solution of 690 g. of 10% hydrochloric acid at 0-5*. The resulting diazonium salt solution was stored below 5“ while the reducing solution was prepared. The diazonium salt solution upon standing yielded a significant amount of a white salt-like solid.

In a 5-1. flask equipped with stirrer eind thermometer were placed 600 ml. of water and 193.0 g. (0.77 mole) of hydrated cupric sulfate. After all the cupric sulfate had dissolved 322.0 g. of concentrated ammonium hydroxide was added and the resulting solution cooled to 10®. A solu­ tion of hydroxylamine sulfate 65.0 g. (0.49 mole) in 190 ml. of water was cooled to 10® and treated with 131 ml. of 6N sodium hydroxide. The resulting solution was added immediately to the stirred ammoniacal cupric sulfate solution. Reduction occurred at once; a gas was evolved and the solution became pale blue. The previously prepared diazonium salt solution was

decanted from the salt like solid into an addition funnel^

The addition funnel was equipped with an ice water cooling bath and a glass tube extension which dipped below the level of the reducing solution and curved upward at the end. 34 The solid was dissolved in 300 ml. of cold water and combined with the diazonium salt solution which was added at a fast drop rate over a 2 hr. period. During the addition the temperature of the reducing solution was maintained at 10-12“ and Dow Silicone Antifoam B was added V when necessary to control excess foaming. The reaction mixture was stirred 5 min., heated to 90“ over a 45 min. period and 600 ml. of concentrated hydrochloric acid added. The resulting mixture was cooled, filtered and the crude product washed with 1 1. of water. The crude product was dissolved in 300 ml. of 10% sodium hydroxide and treated with 15.0 g. of zinc dust. After heating to 80“ the mixture was filtered and the cooled filtrate acidified with 18% hydrochloric acid. The resulting solid was filtered, washed with 500 ml. of water and dried at 80% to yield 63. o. g. (94%) of crude tannish white Va. The crude product was recrystallized twice from methanol to yield 37.0 g. (55.2%) of white crystalline Va, m.p. 253- 255“.

Anal. Calcd. for C^q H^q O^ . c, 72.5; H, 6.1

Pound ; C, 72.2; H, 6.0 Other runs using crude IVa yielded 44-52% of purified product. 35 2,2*-Bis(hydroxymethyl)-5,5 * 6,6*-tetramethylbiphenyl (Vila)» In a 5-1. flask equipped with stirrer and condenser were placed 41.0 g. (1.08 mole) of lithium aluminum hydride and 3 1. of dry ether. The resulting mixture was stirred at reflux 5 hr. and then 99.0 g. (0.33 mole) of purified solid Va was added in small portions through a Gooch tube. The resulting mixture was refluxed 17 hr. The mixture was cooled to 0®. 1.5 1. of ether added, and then 200 ml. of water added dropwise. The resulting white mixture was filtered through Hyflo Super-Cel and the aluminum salts washed with 2 1. of ether. The filtrate was concentrated to dryness and the resulting pale yellow solid recrystallized from 500 ml. of benzene to yield 82.0 g. (90.5%) of white crystalline Vila, m.p. 135-137°. Anal. Calcd. for : C, 80.0; H,8.2

Pound : C,80.1; H,8.2 2,2*-Bis(bromomethyl)-5,5*,6,6*-tetramethylbiphenyl (Villa). In a 2-1. flask equipped with stirrer, addition funnel and thermometer were placed 900 ml. of dry benzene, 27.9 g . (0.10 mole) of Vila and 2 ml. of pyridine. After dropwise addition of 67.0 g. (0.25 mole) of phosphorus tribromide the solution was heated at 58-60° for 2 hr. and then poured into 1 1. of water. The organic layer was separated, washed with 1 1. of water, 800 ml. of 5% sodium bicarbonate and treated in the usual manner. The resulting white oil, 41-0 g. was recrystallized from 200 ml. of ji- to yield 36.0 g. (90.4%) of white crystalline Villa, m.p. 111.5-113°.

Anal. Calcd. for * ^,54.6; H,5.1

Pound ; C,54.5; H,4.9 Other runs using the same procedure gave 83-85% yields. 3,4,5,6-Tetramethy1-9,10-dihydrophenanthrene (IXa) In a 1-1. flask equipped with stirrer, condenser, addition funnel and nitrogen inlet tube were placed 180 ml. of anhydrous ether and 7.2 g. (1.04 g. atoms) of lithium ribbon cut in fine pieces. To the resultingmixture under nitrogen was added dropwise over a 3 hr. period 75.0 g. (0.48 mole) of bromobenzene in 300 ml. of anhydrous ether. During the addition the reaction mixture was cooled in a water bath. Upon completion of the addition the mixture was refluxed 10 min., filtered through a glass wool plug and diluted with 500 ml. of anhydrous ether. The resulting solution was heated to reflux and 60.0 g, (0.15 mole) of Villa dissolved in 700 ml. of anhydrous ether was added dropwise over a 3.5 hr. period. Upon completion of the addition the mixture was refluxed 1,5 hr., stirred at room temperature 12 hr., and then poured on 500 g. of ice. The organic layer was separated, washed with water, 5% hydro­ chloric acid, 5% potassium carbonate and treated in the usual manner. The resulting colorless oil yielded 44.0 g. of crude product, b.p. 60-175° at 1.5 mm. Redistillation afforded 29.6 g. (83.6%) of IXa,b.p. 155-165° at 1.7 mm. This material was shown to be better than 98% pure by g.l.c. The resulting clear oil upon recrystallization from 75 ml. 37 of absolute ethanol yielded 27.0 g. of white crystals, m. p. 98-100*. Anal. Calcd. for : C,91.5; H,8.5

Pound : 0,91.3; H,8.4 3,4,5,6-Tetramethylphenanthrene (Xa). In a 300 ml. steel bomb equipped with glass liner were placed 5.0 g. of IXa, 40 ml. of reagent benzene and 7.5 g. of 5% rhodium- on-alumina. The bomb was flushed with nitrogen and heated at 300-305“ for 10 hr. The resulting mixture upon fil—/. tration and concentration to dryness yielded 5.1 g. of crude product which by g.l.c. contained 46% IXa, 51% Xa and 3% of an unidentified impurity. The crude product was dissolved in 25 ml. of hexane and chromatographed over 450 g. of alumina. The column was eluted with 6 1. of hexane and then 5 1. of 5% benzene-hexane. The first eluate yielded 2.5 g. of IX a ( 90% pure). The second eluate yielded 2.4 g. of Xa (^ 97% pure). The 2.4 g. upon recrystallization from ethanol yielded 2.1 g. of white crystalline Xa, m.p. 70.0-71.2*.

Anal. Calcd. for C^s“l8 * 92.3; H, 7.7

Pound : C, 92.3; H , 8.0 38

CH.

CE

J=8 c.p.s

7.71 2.00 2.73 Tau Values Scale 1H= 8 mm.

Pig. 1 Nuclear Magnetic Resonance Spectrum of 3,4,5,6-Tetramethylphenanthrene

In a run in which the thermocouple failed and the bomb became hotter than 310* a 50% yield of an orange- yellow material m.p. 150-152“ was isolated. This material upon recrystallization from benzene-ethanol yielded, with little loss, colorless needles, m.p. 151-152* which were identified by n.m.r. as 3,5-dimethyl-4H-cyclopenta j^ef j phenanthrene. Anal. Calcd. for ; C, 93.5; H, 6.5

Found ; C, 93.2; H, 6.4 39

CE

e e

OH.

c,d =8 c.p.s

7.58 2.54 6.25 Tau Values Scale 1H= 8 nM.

Fig. 2 Nuclear Magnetic Resonance Spectrum of 3,5- Dimethyl-4H-Cyclopenta jjDef] Phenanthrene

III. Synthesis of 2,4,5,7-tetramethylphenanthrene 2,4-Dimethyl-isonitrosoacetanilide(Ilb). In a 5-1. flask equipped with stirrer and thermometer were placed 1.5 1. of water, 72.0 g. (0.44 mole) of chloral hydrate, 210.0 g. of anhydrous sodium sulfate, 88.0 g, (1.28 mole) of hydroxylamine hydrochloride in 500 ml. of water, and a solution of 48.4 g. (0.40 mole) of freshly distilled 2,4- dimethylaniline (Eastman Practical) in 450 ml. of water containing 42.0 g. of concentrated hydrochloric acid. The 40 resulting solution was heated slowly over 3 hr. to 80®. At 56® a white solid began precipitating from the solution. The resulting mixture was cooled and filtered. The result­ ing brown solid was washed with 500 ml. of water and dried at 80® to yield 39.0 g. (50.7%) of lib, m.p. 158-169“ (lit. m.p. 158-159®).^ The filtrate was returned to the re­ action flask and 130.0 g. of potassium bicarbonate added in small portions. Then 72.0 g. (0.44 mole) of chloral hydrate was added and the resulting solution heated to 82® over a 1.5 hr. period. After cooling, the brown pre­ cipitate was filtered, washed with 500 ml. of water and dried at 80® to yield 13.0 g. (16.9%) of lib, m.p. 152- 159®. The total yield was 52.0 g. (67.5%). An analytical sample of lib was prepared by recrystallizing the crude product twice from benzene-ethanol (19:1). In this manner white crystalline lib, m.p. 173-175® was isolated. This material was analyzed because of the melting point discrepancy.

Anal. Calcd. for ^]_o'^i2^2^2 ' 62.5; H, 6.1

Pound : C, 62.7; H , 6.3 5,7-Dimethylisatin (Illb). The preparation of Illb was carried out essentially as described for the preparation of Ilia. Thus, 50.0 g. (0.25 mole) of crude lib was treated with 550 ml. of anhydrous hydrofluoric acid. The crude product was purified as previously described in the preparation of Ilia. In this manner was isolated 39.0 g. (89.2%) of orange Illb, m.p. 249-251® (lit. m.p. 243®).^ 41 2-Amlno-3,5-Dimethylbenzoic Acid(IVb). In a 3-1, flask equipped with stirrer and addition funnel were placed 80.0 g. (0.46 mole) of Illb and 900 ml. of water containing 22.0 g. (0.55 mole) of sodium hydroxide. After heating until a solution was obtained 80.0 g. of potassium chloride was added. The resulting solution was cooled to 10® and treated dropwise over a 3.5 hr. period at 10-12® with 90.0 g. (0.80 mole) of 30% hydrogen peroxide dissolved in 800 ml of water containing 72.0 g. (1.80 moles) of sodium hydroxide. Upon completion of the addition 180 ml. of acetic acid was added dropwise. The resulting yellow solid was filtered, washed with 800 ml. of water and dried at 80® to yield 74.0 g. (98.4%) of IVb which softened at 178® and melted at 192-194®. (lit. m.p. 188-189“).^ Other runs using essentially the same procedure gave 96-97% yields. 4,4* ,6,6? -Tetramethyldiphenic Acid (Vb). The pre*- paration of Vb was carried out essentially as described for the preparation of Va. Thus, 230.0 g. (1.39 moles) of IVb was diazotized and the diazonium salt coupled. The resulting crude orange-yellow product was dissolved in 1,1. of 10% sodium hydroxide, 50.0 g. of zinc dust added and the resulting mixture heated to 90®. The mixture was filtered hot, diluted to 2 1. and added slowly to 1 1. of concentrated hydrochloric acid. The resulting solid was filtered, washed with 2 1. of water and dried at 90® to yield 172.0 g. (82.7%) of cream-white Vb suitable for 42 estérification. The crude product could be purified further with considerable loss by three recrystallizations from methanol. In this manner in several other runs 50-50% of white crystalline Vb, m.p. 275-282" w. dec. was isolated. Anal. Calcd. for : C, 72,5; H, 6.1

Pound : C, 72.3; H, 5.9 Diethyl 4,4*,6,6'-Tetramethyldiphenate (VIb). In a 3-1. flask equipped with a column and phase-separating head were placed 172.0 g. (0.58 mole) of crude Vb, 1 1. of absolute ethanol, 1 1. of dry benzene, and 5 ml. of concentrated sulfuric acid. The resulting solution was refluxed 2 days. One liter of solvent was removed by distillation and replaced with 1 1. of dry benzene. Another liter of solvent was distilled and the reaction mixture then poured into 500 ml. of 10% potassium carbonate. The resulting mixture was extracted with 1 1. of 1:1 ether-benzene and the organic layer treated in the usual manner. Two vacuum distillations of the resulting dark liquid yielded 145.0 g. (70.9%) of yellow liquid VIb, b.p. 185-195° at 1 mm. A colorless analytical sample m.p. 70.5-71.5° was prepared by re­ crystallization from absolute ethanol.

Anal. Calcd. for ^22'^26°4 ' 74.6; H, 7.4

Found : C, 74.6; H, 7.4 2,2'-Bis(hydroxymethyl)-4,4',6,6'-tetramethylbiphenyl (Vllb). In a 5-1. flask equipped with stirrer, condenser and addition funnel were placed 1 1. of dry ether and 38.0 g. 43 (1,0 mole) of lithium aluminum hydride. The resulting mixture was refluxed 2 hr., 141.6 g. (0.40 mole) of VIb in 1 1. dry ether added dropwise at a rate so as to maintain a gentle reflux and the resuMng mixture heated at a gentle reflux 16 hr. The mixture was cooled to 0“, 1 1. of ether added and carefully hydrolyzed with 152 ml. of water. The resulting mixture was heated to reflux, filtered and the aluminum salts washed with 2 1. of ether. The filtrate upon concentration to dryness yielded 50.0 g. of crude product. The aluminum salts were treated with 2 1. of dilute sulfuric acid and the resulting mixture extracted twice with 2 1. portions of ether. The ether extracts were washed with 10% potassium carbonate and treated in the usual manner. In this manner was isolated an additional 55.0 g. of crude product. After two recrystallizations from benzene-ethanol (98:2) the combined crude product yeilded 99.6 g. (92.6%) of white crystalline Vllb, m.p. 172-175°.

Anal. Calcd. for ^18^22^2 ' 80.0; H, 8.2

Found : C, 80.2; H, 8.2 The dialcohol Vllb was prepared in 88% yield by reduction of purified Vb essentially as described for the preparation of Vila. 2,2'-Bis(bromomethyl)-4,4'.6,6*-tetramethylbiphenyl (Vlllb). The preparation of Vlllb was carried out in the same manner as described for the preparation of Villa. Thus, 96.0 g. (0.36 mole) of Vllb in 2900 ml. of dry 44 benzene containing 3 ml. of pyridine was treated with 260. 0 g (0.97 mole) of phosphorus tribromid^. Upon three recyrstallizations from Skellysolve B the crude product yielded 124.5 g. (88.6%) of white-crystalline Vlllb, m.p. 132.5-134°. Anal. Calcd. for C^gHggBrg : C, 54.6; H, 5.1

Pound : C, 54.8; H, 5.2 2,4,5,7-Tetramethyl-9,10-dihydrophenanthrene(IXb). The preparation of IXb was carried out in the same manner as described for the preparation of IXa. Thus, 12.0 g. (1,73 g. atoms) of lithium in 300 ml. of anhydrous ether was treated with 125.0 g. (0.80 mole) of bromobenzene in 400 ml. of anhydrous ether. The resulting phenyllithium solution diluted with 700 ml. of anhydrous ether was treated drop- wise with 93.0 g. (0.23 mole) of Vlllb in 1700 ml. of anhydrous ether over a 4 hr. period. The crude product yielded upon two vacuum distillations 8.4 g. of liquid b.p. 120-176° at 6 mm, and 44.0 g. (79.29°) of white solid IXb b.p. 160-175° at 1 mm. The 8.4 g. cut was shown by g.l. c. to contain 42% (3.5 g, 6.3%) of IXb. The 44 g. cut was better than 99% pure by g.l.c. The 44.0 g. cut yielded upon two recrystallizations from ethanol 41.4 g. of white crystals, m.p, 85-87°. Anal. Calcd. for : C, 91.5; H, 8.5

Found : C, 91.8; H, 8.3 2,4,5,7-Tetramethylphenanthrene(Xb). In a 300 ml. steel bomb equipped with glass liner were placed 5.9g. of IXb, 45 ml. of reagent benzene and 9.0 g. of 5% rhodium- ,45 on-alumina. The bomb was flushed with nitrogen and heat­ ed at 302-306" for 10 hr. The resulting mixture was filtered and concentrated to dryness. The concentrate, 6.1 g., by g.l.c. contained 5.6% of an.impurity with a shorter retention time than starting material (impurity A), 4 0.5% IXb, 8.3% of an impurity with a retention time slightly less than product (impurity B) and 45.6% Xb. The crude mixture was dissolved in 25 ml. of hexane and chromatographed over 450.0 g. of alumina. The results of this chromatography are listed in Table I.

TABLE I Chromatographic Purification of 2,4,5,7-Tetramethy1phenanthrene % by g.l.c.

Eluate g. of solid A IXb B Xb 3.5 1 :Hexane 2.8 15 85 1.8 1. 11 0.4 37 56 7

0.7 1. It 0.1 8 6 86

3.0 1. II 1.1 , 5 95 4.0 1. 5% Benzene-Hexane 1.4 20 80

The third and fifth cuts were combined and recrystallized three times from hexane. The resulting 0.6 g. of material was combined with the fourth cut and the combined product recrystallized from hexane. In this manner was isolated 1.4 g. (23.6%) of white crystalline Xb, m.p. 111-113". 46 Anal. Calcd. for C^gH^g : C, 92.3; H, 7.7

Pound : C, 92.4; H, 7.7 This material was better than 99% pure by g.l.c. The filtrates from all recrystallizations were combined and concentrated to dryness. The resulting 1.4 g. of crude product could be purified further by chromatography and recrystallization but only with great loss.

QH,

OH,

CE

7.58 7.65 2.79 2.93 Tau Values Scale 1H= 8 mm.

Fig. 3 Nuclear Magnetic Resonance Spectrum of 2,4,5,7-Tetramethylphenanthrene

Impurities A and B were never isolated in sufficient purity to allow identification. The n.m.r. of a mixture of product and B showed that B was not 2,6-dimethyl-4H- 47 cyclopenta j^def J phenanthrene. In several other runs when the crude product was treated with hexane a small amount of insoluble yellow crystalline material was isolated. This material upon recrystallization from benzene-hexane yielded a white crystalline material m.p. 240-241“. This material was identified by n.m.r. as the known 2,7-dimethylpyrene, (lit. m.p. 238.5“).5

5P. Runge and A. Meckelburg, Chem. Ber. 8^, 373 (1953) 48 IV. The Synthesis of 3,4,5,6-tetramethyl- 9, IQ-phenanthrenequinone, (Xlla. ) Dimethyl 5,5' ,6,6*-tetramethyldiphenate^(XIa), In a 1-1. flask equipped with stirrer and condenser were placed 58.0 g. (0.19 mole) of crude Va, 400 ml. of methanol saturated with anhydrous hydrochloric acid, and 130 ml. of 2 ,2-dimethoxypropane. After stirring 16 hr. at room temperature and 2 hr. at reflux the mixture was concentrated to 200 ml. and added to 500 ml. of 10% potassium carbonate. The resulting mixture was extracted with 500 ml. of 1:1 ether-benzene and the organic layer treated in the usual manner. The resulting black oil was vacuum distilled twice to yield 57.0 g. of yellow product, b.p. 185-195* at 2 mm which solidified. The crude product was re­ crystallized twice from 200 ml. of 65-110“ petroleum ether to yield 46.0 g. (72.7%) of white crystalline XIa, m.p. 106-107*. Anal. Calcd. for : C, 73.6; H,6.8

,, .Pound : C, 73.5; H.A.?

3,4,5,6-Tetramethyl-9,10-phenanthrenequinone, Xlla. In a 500 ml. flask equipped with high speed stirrer, condenser and nitrogen inlet tube was placed 250 ml. of xylene. The xylene was heated to reflux and 125 ml. dis­ tilled to dry the system. Sodium, 6.0 g. (0,25 g. atom) was added under nitrogen, the resulting mixture stirred vigorously and 5.0 g. (0.015 mole) of XI a in 100 ml. 49 of refluxing dry xylene added all at once. The resulting orange-red mixture was stirred at reflux 3 hr., cooled to 20* and the excess sodium decomposed by the dropwise addition of 60 ml. of methanol. To the resulting mixture was added 200 ml. of 10% hydrochloric acid. The organic layer was separated, washed with water, 10% potassium carbonate, and treated in the usual manner to yield 3.2 g. of red solid. The basic extract was acidified, extracted with benzene-ether and the organic extract treated in the usual manner to yield 1.2 g. of unidentified yellow glass­ like material. The 3.2 g. of red solid waS dissolved in 75 ml. of benzene. The benzene was concentrated and petroleum ether, (65-110*) added until a solid appeared. The resulting mixture upon cooling and filtration yielded 1.8 g. of orange solid. The filtrate was concentrated to dryness and the resulting red oil recrystallized from 20 ml. of 95:5 ethanol-benzene. In this manner an additional 0.4 g. of orange solid wasisolated. After recrystallization from benzene-petroleum ether and ethanol-benzene followed by sublimation the combined crude product yielded 1..5 g. (37.5%) of yellow Xlla, m.p. 194.8-196*. The I. R. showed a strong carbonyl band at 5.92^|. Anal. Calcd. for : C, 81.8; H, 6.1

Found : C, 81.6; H, 6.1 In a run in which the reaction time was 5 hr. only a 7% yield was obtained. In a run in which ^-cymene-xylene was used as a solvent and the reaction was carried out at 50 145-150° for 1 hr. and 10 min. no quinone was isolated. V. Synthesis of 2,4,5,7-Tetramethyl-9-10- phenanthrenequinone(xilb) Dimethyl 4,4 * 6,6 *-tetramethyIdiphenate(Xlb). In a 1-1. flask equipped with stirrer and condenser was placed 300 ml. of anhydrous methanol. Anhydrous hydrogen chloride was bubbled in for 15 min. and then 55.0 g. (0.18 mole) of crude Vb and 70 ml. 2,2- dimethoxypfopane was added. The resulting solution was stirred 6 hr. at a gentle reflux and 15 hr. at room temperature. The solution was concentrated to 100 ml., 800 ml. of benzene added and poured into 400 ml. of 10% potassium carbonate. The organic layer was separated and treated in the usual manner. Two vacuum distillations of the resulting dark oil yielded 16.0 g. of yellow liquid b.p. 110-180° at 1 mm. and 36.0 g. of yellow solid b.p. 185-205° at 1 mm. The 16.0 g. of yellow liquid yielded after one recrystallization from 75 ml. of ethanol 6.0 g. of pale yellow solid. This material was combined with the 36.0 g. of yellow solid and recrystallized three times from 9:1 ethanol-benzene to yield 37.0 g. (61.6%) of white crystalline Xlb, m.p, 155.

5-156.5°.

Anal. Calcd. for ^20^22^^ ' H, 6.8

Found : C, 73.4; H, 6.6

2,4,5,7-Tetramethyl-9.10-phenanthrenequinone (Xllb). In a 500 ml, flask equipped with high speed stirrer, condenser, and nitrogen inlet tube was placed 250 ml. of xylene. The xylene was heated to reflux and 200 ml. was distilled to dry the system. Then 110 ml. of 2-cymene was added and 30 ml. of solvent distilled. Sodium, 7.0 g. (0.30 g.-atom) was added under nitrogen •and the resulting mixture stirred vigorously. The resulting dispersion was cooled to 140° and 100 ml. of refluxing _£-cymene containing 5.0 g. (0.015 mole) of Xlb was added all at once. The temperature rose to 160° and the mixture turned red. The mixture was stirred 1 hr. at 153-157°, cooled to 20° and the excess sodium decomposed ^y the dropwise addition of 60 ml. of methanol To the resulting mixture was added 200 ml. of 10% hydrochloric acid. The organic layer was separated, washed with water, 10% potassium carbonate, and treated in the usual manner, to yield 3.9 g. of red solid. The base extract was acidified, extracted with benzene-ether and the organic extract treated in the usual manner to yield 1.0 g. of unidentified yellow-white solid. The 3.9 g. of red solid was recrystallized three times from 9:1 ethanol-benzene, sublimed, and recrystallized from ethanol-benzene, to yield 1.8 g. (45%) of Xllb as orange needles which softened at 195° and melted at 199-200,4°. The I, R. showed a weak carbonyl band at 5.88/W and a strong carbonyl band at 5.9/V

Ana'l. Calcd. for C^gH^gOg : C, 81.8; H, 6.1

Found : C, 81.7; H, 6.0 Other runs using essentially the same procedure gave yields of 40-44%. 52 VI. 4,5-Dimethylphenanthrene In a 250 ml. flask equipped with stirrer, condenser and thermometer was placed 80 ml. of dry ether. The flask was cooled in ice water and 39.9 g. (0.30 mole) of anhydrous aluminum chloride added in small portions. To the result­ ing solution was added slowly 7.6 g. (0.20 mole) of lithium aluminum hydride. The resulting mixture was refluxed 10 min. and 4.4 g. (0.02 mole) of the cyclic ether of 4,5- phenanthrenedimethanol was added all at once. The result­ ing mixture was heated in a 75“ oil bath and solvent was distilled until the pot temperature reached 66*. The mixture was heated at 66-68" for 42 hr. After 18 hr. 20 ml. of dry ether was added to facilitate stirring. The mixture was cooled and added to 400 ml. of ether. The mixture was filtered through Hyflo Super-Cel and the filtrate carefully hydrolyzed with 300 ml. of water. The organic layer was separated and treated in the usual manner. The resulting dark oil, 4.3 g., was dissolved in 50 ml. of 1:1 hexane-benzene and chromatographed over 75 g. of alumina to remove the color. The resulting 2.7 g. of pale green oil by g.l.c. contained 54% 4,5-dimethylphenanthrene 42% dihydropyrene and 4% 4,5-dimethyl-9,10-dihydrophenanthrene. The green oil was dissolved in 40 ml. of xylene and 20.0 g. of camphene and 2.0 g. of 5% palladium on charcoal were added. The resulting mixture was stirred at a vigorous reflux for 18 hr. The mixture was filtered and the filtrate concentrated to dryness. The resulting 2.7 g. of 53 oil by g.l.c. contained 46% product, 46% pyrene, and 8% 4,5-dimethyl-9,10- dihydrophenanthrene. The crude oil was dissolved in 20 ml. of 5% benzene-hexane and chromatographed over 175.0 g. of alumina. The column was eluted with 4200 ml. of hexane and 1 1. of hexane- benzene (9:1). The progress of the pyrene was followed by ultraviolet light. The first cut,1200 ml. of hexane yielded 0.3 g. of material which by g.l.c. contained 80% 4,5-dimethyl-9,lO dihydrophenanthrene and 20% product. The second cut, 3000 ml. of hexane yielded 1.2 g. of material which by g.l.c. contained better than 97% product. The third cut, 1 1. of 10% benzene-hexane, yielded 1.1 g. of material which by g.l.c. contained 90% pyrene and 10% product. The second cut yielded upon recrystallization from ethanol 1.1 g. (26.8%) of white crystalline product, m.p. 77.2-78.4“ (lit.^ m.p. 76.3-76.9). The third cut yielded upon recrystallization from ethanol 0.8 g. of 7 white crystalline pyrene, m.p. 149.8-151“(lit. m.p. 151. 3-15). In several larger runs the major part of the,pyrene was removed before chromatography by picrate formation.

^ M. S. Newman, and H. Whitehouse, J. Am. Chem. Soc. 21, 3664 (1949). ^M. S. Newman, J. Org. Chem. _1§, 860 (1951). 54 VII. 4,5-Dimethyl-9,10-phenanthrenequinone In a 125 ml. flask equipped with stirrer and thermometer were placed 1.0 g. (4.8 millimoles) of 4,5- dimethylphenanthrene and 40 ml. of glacial acetic acid. The mixture was heated to 55*. To the resulting solution was added in portions a warm solution of 1.4 g. of chromic anhydride in 20 ml. of acetic acid and 10 ml. of water. The temperature dropped.to 52* and then rose to 57*. The resulting solution was stirred without external heat for 12 min. The temperature dropped to 53*. The solution was poured on 200 ml. of water and the resulting mixture ex­ tracted with two 100 ml. portions of 1:1 benzene-ether. The organic material was extracted with 10% potassium carbonate and treated in the usual manner to yield 1.2 g. of yellow solid. The yellow solid upon two recrystalliza­ tions from benzene-hexane (6-4) and sublimation yielded 0.3 g. (27.3%) of yellow product, m.p. 163-164.5 (lit.® m.p. 162-162.6*). The I.R. showed strong carbonyl bands at 5.92 and 5.95//. VIII.2,7-Dimethyl- 9 , 10-phenanthrenequinone In a 250 ml. flask,were placed 2.0 g. (9.2 moles) of 2,7-dimethylphenanthrene and 80 ml. of glacial acetic acid. The resulting mixture was heated to 70*, 5.0 g. of chromic anhydride dissolved in 40 ml. of acetic acid and 20 ml. of water added all at once and heated at 65-70“

®G. Wittig, and H. Zimmerman, Chem. Ber. 86, 638 (1953) 55 for 20 min. Then 100 ml. of water was added and the precipitated orange solid filtered, washed with 100 ml. of water, 100 ml. of 95% ethanol, and dried at 80® to yield ,1.5 g. of crude product. The crude product was dissolved in 50 ml. of 1:1 chloroform-benzene and chromatographed over 150.0 g. of silica gel. The column upon elution with 1:1 chloroform-benzene yielded a yellow- orange band and a reddish-black band. The yellow-orange band was eluted and the eluant upon concentration to dryness yielded 0.5 g . of yellow solid. The dark red band was eluted and the eluant yielded upon concentration to dryness 1.1 g. of orange solid. The orange solid yielded after one recrystallization from 9:1 benzene-ethanol 0.97 g. (42. 1%) of orange 2,7-dimethyl-9,10-phenanthrenequinone, m.p. 230.6-231.8® (lit.9 m.p. 224-225®). The I. R. showed a strong carbonyl band at 5.95//. The yellow solid upon recrystallization from 95:5 ethanolbenzene yielded 0.4 g. (17.4%) of yellow crystals, m.p. 206-208.5®. This material was identified by its failure to give a quinoxaline derivative, its n.m.r. and its analysis as 2,7-dimethyl-l, 4-phenanthrenequinone. The n.m.r. showed a singlet at 7.5 or which was assigned to the 7-methyl group and a doublet at 7.85 OT (J= 1.7 c.p.s.) assigned to the 2-methyl

group. 10 The I.R. showed a carbonyl band at 6.06/W / .

9R. Haworth, C. Mavin and G. Sheldrick, J. Chem. Soc. 454, (1934).

^°The^^The n.m.r._ _ _ . of 2 methyl-1,4- naphthalenequinone shows a doublet for the methyl group at 7.830T(J=1*5 c.p.s.) 56 Anal. Calcd. for 81.4; H, 5.2

Pound : C, 81.3; H, 5.0 IX. Synthesis of o-Dineopentyltetramethylbenzene 1,2-Bis(chloromethyl)prehnitene(XIII). In a 500 ml. two-necked flask equipped with condenser andmagnetic stirrer were placed 275 ml. of 22% hydrochloric acid, 20.0 g. (0.15 mole) of prehnitene and 90 ml. of n-. The resulting mixture was heated to reflux and 10.0 g. of paraformaldehyde was added in small portions. The mixture was refluxed 6 hr. (pot temp. 108®). At the end of the second and fourth hour 10.g. of paraformaldehyde was added. The mixture was cooled in an ice bath and after filtration and washing with 200 ml. of water and 200 ml. of 65-110® petroleum ether yielded 5.0 g. of crude XIII. The organic layer of the filtrate was separated and the petroleum ether stripped off. The decane solution was placed in a 1-1. flask containing 275 ml. of 22% hydrochloric acid and 30.0 g. of paraformaldehyde. The resulting mixture was stirred at the reflux for 11 hr. and cooled in an ice bath. The reaction mixture was worked up as previously described to yield 8.0 g. of crude XIII and a comparable decane solution. The decane solution was placed in the reaction flask containing 275 ml. of 22% hydrochloric acid and 25.0 g. of paraformaldehyde and the mixture refluxed 23 hr. After 3 hr. 10.0 g. of paraformaldehyde was added. After 6 hr. 10.0 g. of paraformaldehyde and 50 ml. of conc. hydrochloric acid were added. The reaction mixture was 57 treated as previously described and yielded 5.0 g. of crude XIII and decane solution. The decane solution was washed with 5% sodium hydrogen carbonate, saturated sodium , chloride and filtered through anhydrous magnesium sulfate. The three crops of crude solid were combined with the decane solution and vacuum distilled. In this manner 3.2 g. of impure monochloromethyl prehnitene, b.p. 120-130° at 4 mm. and 24.1 g. (70.2%) of XIII, b.p. 160-153°, at 4 mm. m.p. 127-128° were isolated. Two recrystallizations from Skellysolve C and

sublimation afforded an analytical sample of XIII, m.p. 138.4-139°. Anal. Calcd. for G2.3; H, 7.0; Cl, 30.7

Found : C, 62.4; H, 7.0; Cl, 30.8 1,2-Bis(2.2-dicarbethoxypropyl)prehnitene(XIV). In a 2-1. three-necked flask equipped with stirrer, condenser and addition funnel were placed 800 ml. of absolute ethanol and 25.0 g. (1.08 g.-atoms) of sodium. Upon completion of the ensuing reaction the solution was heated to reflux and 300.0 g. (1.72 moles) of diethyl methylmal- onate added. The resulting solution was refluxed 15 min. and 65.0 g. (0.28 mole) of XIII in 500 ml. of added dropwise. The resulting mixture was stirred at a gentle reflux for 12 hr., 150 ml. of glacial acetic acid added, and 1 1. of solvent distilled. The remaining material was added to 1 1. of water, the organic layer separated and the aqueous layer extracted with 500 ml. of 58 benzene-ether (1:1). The combined organic material v/as washed with 5% sodium bicarbonate and treated in the usual manner. The residue upon vacuum distillation yield­ ed 188.0 g. of diethyl methylmalonate, b.p. 115-120“ at 45 mm. and 142.8 g. of a viscous light yellow liquid, b.p. 225-250“ at 1 mm. The viscous liquid was dissolved in 100 ml. of methanol, cooled and seeded. The resulting light yellow crystals were filtered and washed with 100 ml. of methanol to yield 100.5 g. of XIV, m.p. 59.5-51.0“. The filtrate upon concentration yielded an additional 31.2 g. XIV, m.p. 53-54“. The two crops of product yielded upon recrystallization from methanol 130.4 g. (91%) of XIV, m.p. 53-53.8“.

Anal. Calcd. for ^28^42^8 ' 66*4; H, 8.4

Found ; C, 55.5; H, 8.3 This material was extremely difficult to crystallize initially. A number of solvents and methods were tried unsuccessfully. The viscous liquid finally began to crystallize after standing for six months. 1.2-Bis 1^2.2-Bis(hydroxymethyl)propyl prehnitene(XV). In a 3-1. three-necked flask equipped with stirrer, condenser and addition funnel were placed 1500 ml. of dry tetrahydrofuran and 50.0 g. (1.37 moles) of lithium alu­ minum hydride. The resulting mixture was refluxed 14 hr. and then 137.4 g. (0.27 mole) of XIV in 875 ml. of dry tetrahydrofuran was added dropwise. The resulting mixture was refluxed 15 hr., cooled to 0“, and carefully 59 hydrolyzed with 230 ml. of 20% sulfuric acid. The re­ sulting mixture was heated to reflux, filtered through Hyflo Super-Cel, and the alumina salts washed with 1500 ml. of hot tetrahydrofuran. The filtrate was washed with 600 ml. of saturated potassium carbonate, 600 ml. of saturated sodium chloride, filtered through anhydrous magnesium sulfate and concentrated to 300 ml. Then was added 100 ml. of hot benzene and the solution filtered. The filtrate upon cooling and filtration yielded 75.0 g.

bf XV. Concentration of the filtrate yielded an additional 2.0 g. of XV. The combined product was recrystallized by dissolving in 250 ml. of boiling tetrahydrofuran, fil­ tering and adding 200 ml. of benzene. In this manner 73.7 g. (80.8%) of XV, m.p. 196-199®, was isolated. • Anal. Calcd. for : C, 71.0; H, 10.1

Pound ; C, 71.3; H, 9.7

Tetramethanesulfonate of 1.2-bis 2,2-bis(hydroxy- methyl;propyl prehnitene (XVI)» In a 3-1. three-necked flask equipped with stirrer and addition funnel were placed 1800 ml. of reagent chloroform and 93.0 g. (0.28 mole) of XV. The resulting mixture was cooled to -5“ and 196.0 g. (1.70 moles) of cold methanesulfonyl chloride added all at once. To the stirred mixture was added dropwise 206.0 g. (1.70 moles) of collidine at 0-10°. The mixture was stirred 1 hr. at 5-10° and 2 hr. at 10-15°. The resulting light yellow solution was washed with 600 ml. of 5% hydro­ chloric acid, two 1-1. portions of water, 900 ml. of 5% 60 sodium hydrogen carbonate and treated in the usual manner. The resulting dark oil was dissolved in 400 ml. of chloro­ form, 100 ml. of ether added and the resulting solid filtered and washed with 300 ml. of ether. The crude solid upon recrystallization from 1 1.of acetone-ethanol (3:2) yielded 169.7 g. (94.8%) of XVI, m.p. 133-134°.

Anal. Calcd. for ^24^42^12^4 ' 44.3; H, 6.5; S, 19.7

Pound : C, 44.8; H, 6.4; S, 19.8 1,2-Bis(3-methyl-3-thietanyl)methylprehnitene XVII. To 800 ml. of glycol at 130° in a 3-1 three-necked flask equipped with condenser, thermometer and nitrogen inlet tube was added 200.0 g. of ethanol-wet sodium sulfide nonahydrate, (Baker reagent recrystallized from ethanol). The resulting solution was heated under nitrogen to 195°, 140.0 g. of liquid being distilled off during the heating. The solution was cooled under nitrogen and transferred to an addition funnel. In a 3-1. three-necked flask equipped with stirrer, condenser, addition funnel and nitrogen inlet tube were placed 1700 ml. of distilled Ethyl Cellosolve (ethylene glycol monoethyl ether) and 52.0 g. (0.08 mole) of XVI.

The resulting solution was heated at a gentle reflux and the previously prepared sodium sulfide solution added at a fast drop rate under nitrogen. The resulting light yellow solution was refluxed 1 hr., 1.3 1. of solvent stripped off, cooled in ice and filtered. The crude product was dissolved in chloroformbenzene (1:3) 51 and chromatographed over 250 g. Woelm Alumina Basic. The resulting white solid, 17.0 g. upon recrystallization from benzene-ethanol yielded 13.5 g . (50.5%) of XVII, m.p. 164-166° and 2.7 g. (10.1%) of XXI,m.p. 154-160°.

Anal. Calcd. for ^20^30^2 * 71.8; H, 9.0; S, 19.2 Pound ; C, 71.8; H, 9.2; S, 19.0 o-Dinepentyltetramethylbenzene(XVIII). In a 3-1. three-necked flask equipped with stirrer and condenser were placed approximately 200.0 g. of W-2 Raney nickel, 1.5 1. of absolute ethanol and 12.4 g. (0.037 mole) of purified XVII. The resulting mixture was stirred 6 hr. at 58° and 10 hr. ,at 70°. The mixture was filtered through Hyflo Super-Cel and the Raney nickel washed with 500 ml. of hot ethanol. The filtrate was concentrated to 150 ml., cooled, and filtered to yield 6.2 g. of I,m.p. 96-97.5°. Further concentration of the filtrate yielded 2.4 g. of I, m.p. 95-96.5° and 1.2 g. of I, m.p. 87-90°. Recrystallization of all material three times from ethanol

and sublimation yielded 7.9 g. (75.9%) of XVIII, m.p. 95.5- 97° and 1.1 g. (10.6%) of XVIII m.p. 93-95°. Analysis by g.l.c. showed the higher melting material to be better than ■ 99% pure. Anal. Calcd. for : C, 87.5; H, 12.5

Found : C, 87.6; H, 12.4 62

CE

r 7.12 7.77 7.85Tau Values 9.17. Scale 1H= 5 mm.

Pig. 4 Nuclear Magnetic Resonance Spectrum of o-Dineopentyltetramethylbenzene