Synthesis of polymer-supported Fe3O4 nanoparticles and their application as a novel route for the synthesis of imidazole derivatives

Abstract

Cross-linked poly(4-vinylpyridine) supported Fe3O4 nanoparticles, abbreviated as [P4-VP]-Fe3O4NPs, were easily prepared as a new magnetic polymeric catalyst and efficiently used for the synthesis of imidazole derivatives. The polymeric catalyst was characterized by using of various techniques including field emission scanning electron microscopy, X-ray diffraction, vibrating sample magnetometry and Fourier transform infrared spectroscopy (FT-IR) techniques. According to the obtained results, good dispersion of Fe3O4 nanoparticles on the polymer-support and excellent magnetic property of the catalyst were achieved. Various methods have been reported for the synthesis of multi-substituted imidazoles by the reaction of benzil, aldehydes and amines or ammonium acetate in the presence of various catalysts. These methods have some disadvantages including long reaction times, non-reusability of the catalyst, polluted reaction conditions, effluent pollution, and low yields; therefore, we wish to report an efficient, fast, clean and green method for the synthesis of imidazole derivatives that has been developed by one-pot condensation reaction of benzil, ammonium acetate and aldehydes in the presence of [P4-VP]-Fe3O4 nanoparticles. The catalyst displayed good catalytic activity when applied for the synthesis of imidazole derivatives. Various imidazole derivatives were prepared in high to excellent yields (68–99%) with short reaction time and high purity. The present procedure offers advantages such as short reaction time, simple reaction work-up, and the polymeric catalyst can be regenerated and reused several times without significant loss of its activity.