Efficient [bmIm]OH Catalyzed Diastereoselective Synthesis of Imidazopyridine via Microwave Activation in Aqueous Media

摘要

A novel, efficient, and diastereoselective synthesis of imidazopyridine with high atom economy under microwave activation and [bmIm]OH (1-butyl-3-methylimidazolium hydroxide) promotion from readily available 2-aminopyridine and phenyl acetylene ester has been developed in aqueous condition. The strategy involves acetylene activation by [bmIm]OH that allows facile heterocyclization via double hydroamination of 2-aminopyridine with acetylene derivatives. The reaction rate increases enormously with microwave irradiation. The transformation proceeded smoothly and quantitatively. Furthermore [bmIm]OH was recycled and reused five times without any appreciable decrease in its reactivity and product yield.