Copper(II) oxide nanoparticles as a highly active and reusable heterogeneous catalyst for the construction of phenyl-1H-pyrazolo[3,4-b]pyridine derivatives under solvent-free conditions

摘要

An efficient, highly active and resalable copper oxide nanoparticle catalyzed a regioselective cascade synthesis of phenyl-1H-pyrazolo[3,4-b]pyridine derivatives via three-component domino reactions of aldehydes, alkynes and 3-methyl-1-phenyl-1H-pyrazol-5-amine under solvent-free conditions. Good to excellent yield, short reaction times, cost effectiveness; environmental friendliness, easy workup, and a recyclable catalyst are the important features of this protocol. This is the first endeavor towards the synthesis of phenyl-1H-pyrazolo[3,4-b] pyridine derivatives from 3-methyl-1-phenyl-1H-pyrazol-5-amine, alkynes and aldehydes.