A facile and efficient reaction of α,β-unsaturated ketones and 3-amino-1-phenyl-1H-pyrazol-5(4H)-one in aqueous and acetonitrile medium

Abstract

A facile and efficient synthesis of pyrazolo[3,4-b]pyridines, indeno[1,2-b]pyrazolo[4,3-e]pyridine and benzo[h]pyrazolo[3,4-b]quinoline derivatives from the reaction of α,β-unsaturated ketone and 3-amino-1-phenyl-1H-pyrazol-5(4H)-one under mild conditions was reported. This reaction could be operated in aqueous and acetonitrile medium. The other advantages of this reaction were simple operation, mild reaction conditions, high yields and wide range of substrates. Furthermore, 3-amino-1-phenyl-1H-pyrazol-5(4H)-one was an efficient reagent for the synthesis of these heterocyclic compounds. From the experimental facts, he catalyst p-TSA·H2O and water both played the key role in this synthesis.