Four Component One Pot Synthesis of Benzyl Pyrazolyl Coumarin Derivatives Catalyzed by Metal-Free, Heterogeneous Chitosan Supported Ionic Liquid Carbon Nanotubes

Abstract

In this present communication, four component, one pot synthesis of benzyl pyrazolyl coumarin (5a-m) derivatives achieved from the condensation of phenyl hydrazine (1), ethyl acetoacetate (EAA, 2), various substituted benzaldehyde (3), and 4-hydroxy coumarin (4) in EtOH/H2O using metal-free chitosan supported ionic liquid carbon nanotubes (CSIL@CNTs, 10 mol%) as heterogeneous catalyst reflux at 50 °C for 25–30 min. The optimized conditions and excellent yields of the products were reported. All the synthesized compounds were charecterized by the spectroscopic methods. The main advantages of this reported method using CSIL@CNTs. leads to effective conversions were achieved under reflux conditions without the need of an inert atmosphere. In adition, shorter reaction time, simple work up procedure, easy preparation of the catalyst, and chemoselectivity were siginificantly recorded.