Three_component synthesis of Pyrimido[1,2-a]benzimidazole in the presence of Fe3O4@SiO2-HClO4 as a novel magnetic catalysts

A mild, simple and efficient procedure for the preparation of Pyrimido[1,2-a]benzimidazole derivatives is described using Fe3O4@SiO2-HClO4 as a novel and reusable catalyst. . This catalyst was characterized using different types of methods, including Fourier transform infrared (FT-IR), X-ray powder diffraction (XRD), Thermogravimetric analysis (TGA), Transmission Electron Microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDX) and Scanning electron microscopy (SEM). The catalyst was easily isolated from the reaction mixture by magnetic decantation using an external magnet and reused at least three times without significant degradation in the activity. The products are obtained in shorter times with excellent yields (75–97%) from the multicomponent reaction of 2-aminobenzimidazole (1), malononitrile (2), and Aldehydes (3).