An Optimized Process for Formation of 2,4-Disubstituted Imidazoles from Condensation of Amidines and α-Haloketones

Abstract

The preparation of 2,4-disubstituted imidazoles from the condensation of α-haloketones with amidines is described. The optimal reaction protocol is to add the α-bromoketone solution to the amidine in aqueous tetrahydrofuran in the presence of potassium bicarbonate under vigorous reflux. Imidazole was isolated in 83−91% yield with >95% purity without column chromatography.