Four Component Synthesis of Highly Functionalized Pyrano[2,3-c]pyrazoles from Benzyl Halides

N-methylmorpholine N-oxide and silver oxide (Ag2O) oxidized four component reaction for the preparation of pyranopyrazole with different substituted pattern have been developed which provides rapid access to a library of compounds in good to excellent yields by using benzyl halide, malanonitrile/ethyl cyanoacetate, diethylacetylenedicarboxylate/ethyl acetoacetate and hydrazine hydrate as reactants. This transformation involves the breaking of one C‒O bond and formation of 2 C–C, 2 C–N, and a C‒O bond leading to the formation of a five and six membered ring in one pot operation