Copper-mediated synthesis of pyrazolo[1,5-a]pyridines through oxidative linkage of C–C/N–N bonds

Abstract

Copper-mediated synthesis of pyrazolo[1,5-a]pyridine-3-carboxylates through oxidative linkage of C–C and N–N bonds under mild reaction conditions is described. This protocol is applicable to a variety of pyridyl esters as well as various benzonitriles including nicotinonitrile, isonicotinonitrile and thiophene-2-carbonitrile. Better yields were observed with electron withdrawing substituted benzonitriles.