CuBr catalyzed aerobic oxidative coupling of 2-aminopyridines with cinnamaldehydes: direct access to 3-formyl-2-phenyl-imidazo[1,2-a]pyridines

Copper bromide catalyzed aerobic oxidative coupling of 2-aminopyridines with cinnamaldehydes directly led to the formation of 3-formyl-2-phenyl-imidazo[1,2-a]pyridines. The quantum chemical calculations were performed to trace the reaction mechanism and get insights into the possible reaction pathway. 2-Aminopyridines on coupling with cinnamaldehyde generate (E)-3-phenyl-3-(pyridin-2-ylamino)acrylaldehyde IV as a key intermediate, which undergoes C–N bond formation reaction to produce 3-formyl-2-phenyl-imidazo[1,2-a]pyridines.