Preparation of Immobilized Tribromide on Fe3O4 Magnetic Nanoparticles (Fe3O4-Br3) and its Utilization in the Knoevenagel Condensation Reaction and Synthesis of Polyhydroquinolines

Polyhydroquinolines, as interesting and versatile N-heterocycles, have attracted much attention due to their pharmacological properties, such as antitumor, bronchodilator, antidiabetic, antiinflammatory, antibacterial, and antimalarial agents [1]. Consequently, many different synthetic methods for producing polyhydroquinolines derivatives have been reported using various catalysts. The Knoevenagel condensation is one of the most powerful strategies for carbon-carbon bond formation in organic chemistry [2], and its products have numerous applications in thesynthesis of fine chemical, as well as carbocyclic and heterocyclic compounds of biological significance [3, 4]. In this work, we wish to report use tribromide immobilized on Fe3O4 modified magnetic nanoparticles as new, efficient and reusable catalysts for Knoevenagel condensation reactions and synthesis of polyhydroquinoline derivatives in mild conditions.The separation of catalyst from reaction mixture was performed without needed expensive centrifuges and process of filtering with using an external magnet and reused for several times without significant loss of its catalytic activity is advantaged this catalyst.