Conversion of Carboxyl to Trichloromethyl Group in Reactions of lmidazole and Pyridine-carboxylic Acids with Phosphorus Pentachloride

Abstract

The reactions of varieus imidazole and pyridine-carboxylic acids with phosphorus pentachloride in thionyl chloride were investigated. lt was found that the carbexyl group attached to ev-carbon with respect to unsaturated nitrogen atom could be converted to trichloromethyl group. Examples include the formations of 1-methyl-4-trichloromethyl-imidazole, 4, 5-di-tri chloromethyl-imidazole, 2-trichloromethyl-pyridine, 2-trichloromethyl-pyridine-4 and 5-earboxylic acid from 1-methyl-imidazole-4-carboxylic acid, picolinic acid, imidazole-4, 5-dicaTboxylic acid, pyridine-2, 4 and 2, 5 dicarboxyli acid, respectively. The reaction Mechanism for the conversion of arboxyl to trichloromethyl group was proposed.