Toward versatile methods leading to highly functionalized imidazo[1,2-a]pyridines

A convenient and general method of preparation of polyfunctionalized imidazo[1,2-a]pyridines is reported. This methodology involves activation of secondary amides leading to the formation of the corresponding amidines 9. Different activating reagents have been evaluated and the efficiency of PCl5 was illustrated with alkyl functionalized groups.