Synthesis of Imidazopyridines from the Morita–Baylis–Hillman Acetates of Nitroalkenes and Convenient Access to Alpidem and Zolpidem

A variety of functionalized imidazo[1,2-a]pyridines have been synthesized through a one-pot, room temperature, and reagent-free reaction between MBH acetates of nitroalkenes and 2-aminopyridines. The reaction involves a cascade inter-intramolecular double aza-Michael addition of 2-aminopyridines to MBH acetates. Our methodology is marked by excellent yield, regioselectivity and, above all, adaptability to synthesize imidazopyridine-based drug molecules such as Alpidem and Zolpidem.