Microwave assisted, sequential two-step, one-pot synthesis of novel imidazo[1,2-a] pyrimidine containing tri/tetrasubstituted imidazole derivatives

Abstract

A series of novel imidazo[1,2-a]pyrimidine containing tri/tetrasubstituted imidazole derivatives (1-10) has been synthesized via sequential two-step, one-pot, multicomponent reaction using imidazo[1,2-a]pyrimidine-2-carbaldehyde, benzil, primary amines, and ammonium acetate catalyzed by p-toluenesulfonic acid under microwave-assisted conditions. The results showed that target compounds can be obtained from a wide range of primary amines bearing different functional groups with moderate to good yields (46%-80%) under optimum reaction conditions. This method provides a green protocol for imidazo[1,2-a]pyrimidine containing tri/ tetrasubstituted imidazole derivatives due to ethyl alcohol as a green solvent, microwave irradiation as a greener heating method and one-pot multicomponent reaction as a green technique. The synthesized compounds have been elucidated using various spectroscopic tools such as $FT-IR, ^{1}H NMR, ^{13}C NMR, and MS.$