Fe3O4@SiO2/Bipyridinium Nanocomposite as a Magnetic and Recyclable Heterogeneous Catalyst for the Synthesis of Highly Substituted Imidazoles Via Multi-Component Condensation Strategy

A magnetically separable catalyst consisting bipyridinium supported on silica coated Fe3O4 nanoparticles was prepared. Fe3O4@SiO2/bipyridinium nanocomposite (Fe3O4@SiO2/BiPy(+2)2Cl(-)) was used as a recyclable heterogeneous catalyst for the synthesis of various multi-substituted imidazoles via multi-components cyclocondensation reaction of 1,2-dicarbonyl compounds, aldehydes and N-source compounds under solvent-free conditions. This catalyst afforded the imidazole derivatives as key intermediates in pharmaceutical chemistry in very short reaction times. The catalyst is readily recovered by simple magnetic decantation and can be recycled several times with no significant loss of catalytic activity. However, this catalyst was characterized by FT-IR, TGA, SEM and VSM.