A simple green synthesis of NiFe2O4@ZnO magnetic nanocomposite and its use as an efficient catalyst for the synthesis of polyhydroquinoline derivatives under microwave irradiation

Polyhydroquinolines are one of the most important classes of heterocyclic scaffolds providing major ligands for biological receptors. Polyhydroquinolines the source of some valuable drugs which are very important in pharmacy. For instance, they demonstrate activity for the treatment of angina pectoris and hypertension.1-3 In this work, synthesis of NiFe2O4@ZnO nanocomposite was performed by the green sol–gel method using natural gel. The sample was characterized by Fourier transform infrared spectrophotometer (FTIR), X-ray powder diffraction (XRD), vibrating sample magnetometer (VSM), Transmission electron microscopy (TEM), Field emission scanning electron microscopy (FESEM) and energy dispersive X-ray analysis (EDX). NiFe2O4@ZnO nanocomposite was used as a reusable and robust heterogeneous catalyst for one-pot four component synthesis of polyhydroquinoline derivatives via the esteemed Hantzsch reaction using aryl aldehydes, ethyl acetoacetate, dimedone and ammonium acetate by microwave irradiation under solvent free conditions (Fig 1). The final product was investigated by 1H NMR and 13C NMR spectroscopy. This method has many advantages such as high yields, relatively short reaction times, mild reaction condition, easy work up, and using a highly recyclable catalyst.

Keywords:

Multicomponent reactions , Polyhydroquinoline derivatives , Solvent free , Green synthesis.