Facile Synthesis of Fully Decorated Imidazo[4,5‐b] and Imidazo[4,5‐c] Pyridines in Aqueous DMF via C‐H Activation under Microwave Irradiation

Catalytic C−H bond activation of heteroarenes has gained tremendous potential in recent years due to their environmentally and economically benign nature. In this paper we report the regioisomeric synthesis of fully decorated imidazo pyridines employing a C−H activation protocol with a wide range of aryl/hetero aryl/alkyl boronic acids in aqueous DMF. The use of inexpensive copper catalyst and Bathophenanthroline as ligand were found to be instrumental in driving these reactions to completion. This optimised protocol was further extended to alkyl/aryl/heteroaryl potassium organo trifluoroborates. A wide range of diversely substituted imidazo pyridine analogues which are known for their potential therapeutic applications have been synthesized using this highly efficient and atom economical protocol. An environmentally benign protocol for the catalytic arylation/hetero arylation of imidazopyridines, with a wide substrate scope, and exceptional regioselectivity is reported.