Journal of Pharmaceutical Sciences 1983-04-01

Kinetics and mechanism of hydroxy compound cinnamoylation in acetonitrile catalyzed by N-methylimidazole and 4-dimethylaminopyridine.

C J Eboka, K A Connors

Index: J. Pharm. Sci. 72(4) , 366-9, (1983)

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Abstract

The kinetics of reaction of the acylating agents trans-cinnamic anhydride and trans-cinnamoyl chloride with the hydroxy compounds n-propyl alcohol and water in the presence of N-methylimidazole and 4-dimethylaminopyridine were studied spectrophotometrically in acetonitrile solution at 25 degrees. The acid chloride reacted via the intermediate formation of the N-acyl catalyst, which underwent general base-catalyzed reaction with the hydroxy compound. The anhydride did not form the N-acyl intermediate, but instead underwent direct general base catalysis. In the presence of water, all systems formed the N-acyl intermediate. The mechanistic route followed by the system was determined by the nucleophilicity of the catalyst, the ability of the leaving group, and the polarity of the solvent.