Base-Mediated Syntheses of Di- and Trisubstituted Imidazoles from Amidine Hydrochlorides and Bromoacetylenes.

A new transition metal-free method for the preparation of substituted imidazoles from easy-to-handle amidine hydrochlorides and bromoacetylenes has been developed. The reactions proceed in air and use inexpensive K2 CO3 as base. Additions of 2,2'-bipyridine and water have beneficial effects on the product yields. Various di- and trisubstituted imidazoles have been prepared in good yields (up to 88 %).