Microwave-assisted synthesis of novel 2,3-disubstituted imidazo[1,2-a]pyridines via one-pot three component reactions

An expeditious one-pot, metal-free, three-component reaction of arylglyoxals, cyclic 1,3-dicarbonyls and 2-aminopyridines in the presence of molecular iodine under microwave irradiation is reported. A wide variety of 2,3-disubstituted imidazo[1,2- a ]pyridine derivatives can be synthesized in good to very good yields using this methodology. The salient features of this methodology are: metal-free, short reaction time, good yields, use of microwave heating and no harmful by-products.