A Facile Solvent-Free Route for One-Pot Multicomponent Synthesis of Benzylpyrazolyl Coumarins Derivatives in Presence of Effective Synergetic Catalytic System

摘要

A combinatorial library of benzylpyrazolyl coumarin derivatives have been synthesized by a green one-pot four-component reaction between aryl hydrazine/hydrazine hydrate(1),ethyl acetoacetate(2),aromatic aldehydes(3)and 4-hydroxycoumarin(4)catalyzed by niobium pentachloride with silver salt under solvent-free conditions has been developed.Experimental simplicity,simple work-up procedure and solvent-free reaction condition at room temperature are important features of the present protocol.