Reactions of Substituted Oxazoles and Thiazoles with Acid Chlorides: Carbon-Carbon Bond Formation through Cyclic Ketene Acetals

Abstract

Reactions of 2,4,5-trimethyloxazole, 2,4,5-trimethylthiazole, 2-methylthiazole, and 2-ethyl-4,5-dimethylthiazole with different acid chlorides in the presence of different bases were explored. Arylvinyl esters of substituted benzoic acids containing substituted oxazoles or thiazoles were formed when aroyl chlorides were used. Degrees of aroylation were different with different bases. Reactions with alkyl acid chlorides were also explored. Most of these reactions occurred through cyclic ketene acetal intermediates.