Studies on the Preparation of Cyclamen aldehyde and its Related Compounds
Part 1. Syntesis of p-Isopropyl-α-methylhydrocinnamic Acid by Aectoacetic Ester Method
1955 Volume 29 Issue 2 Pages 91-94
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1955 Volume 29 Issue 2 Pages 91-94
Recently, the present author has attempted a new synthesis of p-isopropyl-α-methylhydrocinnamic acid from the derivatives of ethylacetoacetate, R-_??_-CH2-C(CH3)(COCH3)CO2C2H5 where R-meant H (II) or i-C3H7 (II').
After repeated experiments with alkaline decomposition, the acids (III, III') and ketones (IV. IV') were obtained.
The results may be briefly summarized as follows.
(1) The ketonic-acidic hydrolysis is not influeneced by excess of alkali, but the variation of alkali concetration indicated the results as shown in Fig. 1 and 2.
(2) Presence of the isopropyl-group at para-position on benzene nucleus showed the positive effect in the ketonic hydrolysis (Fig. 2).
(3) Hydrolysis of the esters in alcoholic alkali solution gave considerably higher yield for the acids (III, III') than in aqueous state.
(4) Ba(OH)2 seemed most preferable to obtain the acide (III, III') in the decomposition of the esters.
(5) Under the appropriate conditions, the decomposition of ethyl p-isopropylbenzylace toacetate seemed to of be a more economical method of preparing p-isoproyl-α-methylhydrocinnamic acid than the decomposition of ethyl p-isopropylbenzylmethylmalonate.
