DABCO catalyzed highly regioselective synthesis of fused imidazo-heterocycles in aqueous medium

An efficient regioselective synthesis of 3-aryl imidazo[1,2-a]pyridines, 5-aryl imidazo[2,1-b]thiazoles, and 3-aryl benzo[d]imidazo[2,1-b][1,3]thiazoles is described by the reaction of phenacyl bromide with heterocyclic amine in the presence of DABCO under aqueous medium. The method is applicable for a variety of substituted phenacyl bromides as well as 2-amino-heterocycles. An aqueous reaction medium, regioselectivity, mild reaction condition, and high yield of products are the important features of this protocol.