360
ROGERADAMSAND R. B. CARLIN
methoxy - 6- methylphenyl) - 1- cyclohexene - 5 -carboxylic acid or 4- (2,4-dimethoxy-B-rnethylphenyl) - 1- cyclohexene - 5 - carboxylic acid, thus
[CONTRIBUTION
FROM THE
Vol. 65
demonstrating that two ortho groups will not prevent diene addition to a cinnamic acid. URBANA, ILLINOIS
NOYESCHEMICAL LABORATORY, UNIVERSITY
RECEIVED OCTOBER31, 1942
OF
ILLINOIS]
The Addition of Dienes to Certain Di-o-methoxy-substituted Cinnamic Acids. I1 BY ROGERADAMSAND R. B. CARLIN
In a previous paper,' the addition of 2 3 - aldehyde was converted to 2,6-dimethoxy-4dimethyl-1,3-butadiene or isoprene to coumarin, methylcinnamic acid (11)) which added 2,3trans-o-hydroxycinnamic acid, cis- and trans-o- dimethyl-1,3-butadiene to form the partially methoxycinnamic acids, and 2-methyl-4,6-di- hydrogenated biphenyl (111). 'This procedure was equally successful for the methoxycinnamic acid to form pyrones or partially hydrogenated biphenyl derivatives was preparation of 2,6-dimethoxy-4-n-amylcinnamic described. Application of a similar reaction acid iIV) from the lithium derivative of olivetol provides an approach to the synthesis of a tetra- dimethyl ether. To this molecule isoprene was hydrocannabinol with a double bond in a position added and, with the exception of a single experipostulated for the natural tetrahydrocannabinol ment, the same product (V) was always isolated. obtained by rearrangement of cannabidiol with I n one instance which could not be repeated, an toluenesulfonic acid. addition product with a different melting point As a type compound, %,cj-dimethoxy--l.-niethyl- resulted. This substance may have been the cinnamic acid was selected and prepared for OCH, preliminary study. Bn aldehyde group, when H O O C - - C H = C H a 6 H l l ( n ) + introduced into orcinol dimethyl ether by any of OCH, the usual procedures, enters between the methyl IV OCH, and the methoxyl groups. Advantage was, &~C.H,,,, therefore, taken of the fact that orcinol dimethyl COOH OCHg ether reacts with butyl lithium to give a molecule IT with the lithium attached to the carbon between the two methoxyls.* Replacement of the lithium isomer of V with the methyl group in the other atom by an aldehyde group by treatment with possible position. The position of the methyl orthoformic ester j or ethoxymethylene aniline group in compound V was proved by converting it failed, but S -methylformanilide4 reacted readily to a compound of known configuration. The acid with the formation of the desired aldehyde (I) iV) was esterified to the methvl ester (VI) which By means of malonic acid anti pyridine thii OCH, CH 3 7
OCH8 ( ) H C ~ > C H--+ OCH
> - nL C 5 H l l ( n )-+ d COOCH, OCH,
_i
1'1
OCH I1 CHJ OCH, l3,CC-j -=CHI COOH OzE, .
.-.... ..
111
-
(1) Adams, M c P h e e , Carlin and \ricks 'lais j t J U K N A I . , 66, :4.i (1943). (2) Adams. Wolff, C a i n and Clark. ibzd., 62, l77(l , l!34ll~ r : i J I3r A . A .4lbert 1,rivate communication 11
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