Sulfonic acid supported on Fe2O3/VO2 nanocatalyst: A highly efficient and reusable nanocatalyst for synthesis of spirooxindole derivatives

Fe2O3/VO2/SO3H nanocatalyst is reported for simple, and three-component reaction for the synthesis of spirooxindole derivatives by the reaction of isatin, 1,3-cyclohexadiene and malonitrile in solvent-free condition. The method allows easy construction of a library of spirooxindoles in moderate to good yields. The prepared nanocomposite was characterized using fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), x-ray diffraction (XRD) analysis, and energy dispersive x-ray spectroscopy (EDX). The nanocomposite was easily recovered using an external magnet and reused several times without a significant loss of the efficiency.