Poly(4-vinylpyridine) efficiently catalyzed one-pot four-component synthesis of pyrano[2,3-c]pyrazoles

An efficient one-pot synthesis of pyrano[2,3-c]pyrazoles via four-component reaction of phenyl hydrazine, ethyl acetoacetate, malononitrile and aromatic aldehydes, catalyzed by poly(4-vinylpyridine) is reported. This method provides many advantages such as, atom-economy, easy work up, clean procedure, short reaction times and high yields of products.