Abstract

A nanoclay-catalyzed atom and energy-efficient low hazardous tandem conjugate additioncyclodehydration of cyclic thioureas (ethylenethiourea and 2-mercaptoimidazole/-benzimidazole) with dielectrophiles (chalcones) readily annulates a 1,3-thiazine ring on imidazoles to yield 7H-imidazo[2,1-b]-1,3- thiazines under solvent-free microwave irradiation in a one-pot procedure.

Keywords: Nanoclay-catalyzed, solvent-free, chalcones, cyclic thioureas, microwaves, imidazo-1,3-thiazines