Trichloroacetic acid as a solid heterogeneous catalyst for the rapid synthesis of dihydropyrano[2,3-c]pyrazoles under solvent-free conditions

Abstract

A one-pot, three-component reaction of an aromatic aldehyde, malononitrile and 3-methyl-1-phenyl-2-pyrazolin-5-one in the presence of a catalytic amount of trichloroacetic acid produces a 6-amino-4-aryl-5-cyano-3-methyl-1-phenyl-1,4- dihydropyrano[2,3-c]pyrazole in excellent yield and in a short reaction time. 2011 · Copyright © by Walter de Gruyter.