Copper catalyzed tandem oxidative C-H amination/cyclizations: Direct access to imidazo[1,2-a]pyridines

A simple and convenient strategy is described for the synthesis of imidazo[1,2-a]pyridines via inexpensive copper-catalyzed tandem imine formation and intramolecular aerobic oxidative C-H bond amination/cyclizations. An array of imidazo[1,2-a]pyridines were prepared by the reaction of readily available acetophenones and 2-aminopyridines in good to excellent yields (48-92%). The scope of the method was validated by a single step synthesis of Zolimidine, a drug used for peptic ulcers, in 61% yield.