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

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.