Design, preparation and characterization of urea-functionalized Fe3O4/SiO2 magnetic nanocatalyst and application for the one-pot multicomponent synthesis of substituted imidazole derivatives

Novel urea-functionalized silica-based magnetite hybrid core-shell nanoparticles were prepared and characterized by Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) analyses. It was used as a highly efficient and recoverable heterogeneous nanocatalyst for the one-pot three-component condensation reaction between benzil or benzoin with various substituted aldehydes and ammonium acetate to afford the corresponding imidazoles under mild reaction conditions in high-to-quantitative yields. The catalyst was recycled at least five times without significant decrease in the catalytic activity. (C) 2015 Elsevier B.V. All rights reserved.