Bismuth triflate：A highly efficient catalyst for the synthesis of bio-active coumarin compoundsvia one-pot multi-component reaction

摘要

A series of coumarin-chalcone hybrid compounds and coumarins linked to pyrazoline was synthe-sized in good yield and short time using a simple and efficient method. This method involved the one-pot reaction of salicylaldehyde, an α-ketoester and an aromatic aldehyde (in the case of the coumarin-chalcone derivatives) in addition to hydrazine hydrate (in the case of the pyrazolyl cou-marins) in the presence of a catalytic amount of bismuth triflate [Bi(OTf)3, 5 mol%]. The synthesized compounds showed scavenging activity towards the free radical 2,2-diphenyl-1-picrylhydrazyl. All compounds were characterized using IR,1H NMR and13C NMR spectroscopy.