A transition metal-free cascade reaction using heterogeneous tin(IV)oxide catalyzed and iodine promoted synthesis of 3-aroylimidazo[1,2-a]pyridines

The cascade synthesis of 3-aroylimidazo[1,2-a]pyridines using chalcones and 2-aminopyridine was achieved over the SnO2/I2 catalytic system in toluene at ambient air atmosphere. The catalyst shows high activity towards the broad substrate scope of the various aromatic and heterocyclic chalcones with 2-aminopyridine, 4-methyl 2-aminopyridine, and 5-methyl 2-aminopyridine in good yields during the synthesis of 3-aroylimidazo[1,2-a]pyridines. The...