An efficiently and quickly synthesized NiO@g-C3N4 nanocomposite-catalyzed green synthesis of spirooxindole derivatives

摘要

NiO@g-C3N4 as an efficient catalyst for the synthesis of spirooxindole derivatives was prepared by impregnation of g-C3N4 with NiO nanoparticles and characterized by various techniques including thermogravimetric analysis, transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. The one-pot synthesis of spirooxindole derivatives using 1 mmol isatin, 1 mmol dimedone (or 4-hydroxycoumarin or ethyl acetoacetate) and 1 mmol malononitrile was carried out in the presence of 50 mg NiO@g-C3N4 in EtOH media at reflux conditions. The results showed that both series of reactions had short reaction times (less than 7 min) and high reaction efficiency (greater than 87%). Some advantages can be cited for this method, including short reaction time, excellent yields, easy workup and a reusable and inexpensive nanocatalyst.