435s
LVILLIARZJ. BAILEY,ROBERT L. HGIISON .ZND CHIEN-LYEI Lr.10
Vol.
[ C O N T R I B U T I O N PROM THE DEPAR.rMExTS 01: CHEMISTRY, UNIVERSITY O F f i I A R Y L A N D AND W A Y S E
Cyclic Dienes.
so
STATE U N I V E R S I T Y ]
XXII. Substituted 1,2-Dimethylene-4-cyclohexenes
BY WILLIAM J. U A I L E YROBERT ,~ L. HUDSON~ ASD CIIILN-IVEI LIAO~ RECEIVED DECEMUER 12, 1957 Pyrolysis of 2,3-di-(acetoxy1rietliyl)-~~(~0~-octaliii at 505' produced a 737, S-ield of 2,:3-dimetliyle1ie-A~~~~~-octalin, which is isomeric with the aromatic 6.7-dimethyltetralin. Sirnilnrly, the pyrolysis of 3,6-dimethyl-cis-A4-tetrahydrophthalyl diacetate a t the same temperature produced a 4776 yield of 3,G-di1nethyl-1,2-dimethylene-4-cyclol1ex~ne,isomeric with prehnitene. The structures of the trienes were proved by analyses, infrared and ultraviolet absorption spectra, conversions to solid Diels-Alder adducts, and isomerization to the corresponding aromatic derivatives. T h e isomerization of the 3,6disubstituted triene was surprisingly slow.
It was of interest, therefore, to extend this study Previous work has shown that the pyrolysis of csters is an excellent method for the synthesis of to a variety of other isomers of aromatic comconjugated exocylic dienes.j-ll In an effort to dc- pounds containing a large number of substituents. termine what other highly sensitive unsaturated For this reason the unsaturated diacetate, 2,3-dicompounds could be prepared by this pyrolytic (acetoxymethyl)-Ag!'")-octalin(I),s was pyrolyzed method the syntheses of a series of highly unsatu- a t 505' under such conditions that only 57y0of two rated compounds and polyfunctional compounds molar equivalents of acetic acid was liberated. were undertaken. For example, the pyrolysis of a These conditions were selected in order t o minimize triacetate gave the highly sensitive 2-vinylbuta- any charring in the pyrolysis tube that could dieneI2 in good yields and the pyrolysis of a tetra- cause any rearrangement or aromatization. T o acetate gave a good yield of 2,3-bis-(acetoxyinethyl)-1,3-b~tadiene.~~Further investigation has shown that during a vapor-phase pyrolysis in the absence of any charring there is little tendency for a double bond to rearrange. Thus the pyrolyI11 I sis of hexahydroisophthalyl diacetate gives pure 1,3-dimethyleneeyclohexane even though there is a strong driving force for one of the double bonds to rearrange from an exocyclic position to an endocyclic position into conjugation with the other double bond.14 The synthesis of a series of isoiners of aromatic compounds also vias uiidcrtakcn. The I' IS first compound in this series, 1!2-dintethylcnc-4cyclohexene, isomeric with o-xylene, was prepared in a 92% yield by the pyrolysis of an unsaturated diacetate.15 Spectroscopic evidence indicated that no o-xylene was present in the pyrolysate. This synthesis was extremely significant in view of the fact that the decomposition of the corresponding bis-quaternary ammonium hydroxide gives oxylene as the only product.lG The synthesis of isomers of aromatic compounds was then extended to the preparation of 4-1nethyl-l-2-dimethylene-3cyclohexene, isomeric with pseudocumene, a t i d 4,5-dimethyl-l,2-di1nethylene-4-cyclolicxene, isomeric with durene."
+
(1) Previous paper in this series, THISJOURX.AL, 79, tj5lG (1937). (2) Department of Chemistry, University of Maryland, College Park, Md. (3) Oliice of S a v a l Research Fellow, Wayne State University, 1050-
maleic anhydride
--_____J
_ _ I _ _ _ _
18jI ; University of JLarylanil, 19.jl--IQ2 1. (4) Office of Fava1 Research Fellow, Wayne State University, 1 3 3 . ( 5 ) W.J. Bailey and € I . R . Golden, THIS J O U R X A L , 76, 4780 (1953) ((i) W. J. Bailey, J . Rosenberg and 7,. J. Young, ibid., 1 6 , 21'51
'I
I Pd-C
j.
CHI
(1954).
(7) W . J . nailey and \V. I?. Sorenson, ;bid., 1 6 , 5,121 (1834). ( 8 ) W . J . Bailey, C -\V, I.iao and G. 1%.Coleman, ibid.,1 7 , 9 9 0 ( l!l.p)3). (!I) W. J. Bailey and 11. 1,. €Indsori, ibiii., 78, 670 (19,jG). (10) W. J. Bailey aud \V. H. Lawson, i b i d . , 71, 1606 (192.5); 79, 1414 (19Z7). (11) W. J. Bailey and W. A . Klein, i b i d . , 79,3 1 2 1 iiY57). (12) \V, J. Ilxiley and 5 . I':cuo
J O U R N ~ I , 63, ,
31111
BAKERLABORATORY O F CHEMISTRY, CORNELL UNIVERSITY]
Polynuclear Aromatic Hydrocarbons. IX. The Synthesis of 3,4-Benzpyrene and 7-Meth~1-3~4-benzpyrene B Y DONALD
D.
PHILLIPS' AND
D. N.
CHATTERJEJC"
RECEIVED FEBRUARY 28, 1958 The synthesis of 3,4-benzp]-rene (X) and 'i-methyl-3,4-benzpyrene ( X I ) from 5-keto-~,rj,6a,7,8,9,10,10a-o~tah~-clr~icliryseue (I) is described. The ketone I was converted by the Reformatsky reaction to a mixture of the two unsaturated acids 111 and IV which were reduced and cyclized to the corresponding ketones VI1 arid TTII. When either \'I1 or 1'111 'ims reduced and dehydrogenated, 3,4-benzpyrene ( X ) was obtained. Treatment of VI1 with methylmagnesium iodidc followcd by dehydrogenation afforded 7-methyl-3,4-benzpyrene ( X I ) , one of the two monometh~l-3,4-benzpyreneswhose synthesis has yet to be described. The attempted preparation of X by the cyclodehydrogenation of XI1 and XI11 afforded chrysene by the ejection of an ethyl group.
In a recent communication4we reported the preparation of the ketooctahydrochrysene (I) from naphthalene and trans-2-hydroxy-cyclohexaneacetic acid lactone. It became apparent that this ketone (I) could serve not only as a useful precursor to the chrysene ring system but also to the im(1) Paper V I I I , D. D. Phillips and T. B. Hill, THISJOURNAL, 80, 3663 (1968). (2) To whom inquiries regarding this article should be sent. Shell
Development Co., Modcsto, Calif (3) Krishnagar C
