An Eco-friendly Solvent-free Synthesis of Trisubstituted Methane Derivatives Catalyzed by Magnetic Iron Oxide Nanoparticles as a Highly Efficient and Recyclable Catalyst

Background: Up to date, numerous attempts for the synthesis of potentially interesting medicinally important heterocyles and organic compounds by application of a wide range of homogeneous and heterogeneous catalysts under green conditions have been made and published. The abundance and variety of diseases and the needs of mankind for treatment of them have made these attempts inevitable. Furthermore, among highly active catalysts, nano-sized Lewis acids play an outstanding role in organic synthesis. Considering all the above facts, herein, numerous potentially interesting biologically active organic products have been synthesized and reported by the use of magnetic iron oxide nanoparticles under green conditions with good to excellent yields. Methods: An efficient and environmentally adapted synthetic route to tri-substituted methanes syntheses by the use of Fe3O4 nanoparticles as a green and recyclable Lewis acid catalyst is introduced. The chemical structures of all obtained products were deduced and confirmed by their 1H NMR, 13C NMR, IR spectroscopies, and elemental analyses (C, H, N, S). Results: In this study, magnetic iron oxide nanoparticles (Fe3O4 NPs) as an highly efficient, recyclable and eco-friendly heterogeneous Lewis acid catalyst have been successfully applied to the green and promoted synthesis of a newly prepared type of tri-substituted methane derivatives containing 4- hydroxycoumarin, arylaldehydes, and N,N-dimethylbarbituric acid under mildly solvent-free conditions via a Domino reaction. In some cases, condensed products via Knoevenagel coupling reaction are only obtained under given conditions. This procedure using Fe3O4 NPs has some advantages synthetically and from industrially point of view including obtaining excellent yields of products, short reaction times, green and safety protocol, ease of handling, and capability of catalyst for reuse. Conclusion: By this achievement, the scope of organic products and potentially biological active compounds has been developed. One-pot synthesis of products under green conditions using reusable magnetic Fe3O4 nanoparticles as catalyst with high yields could attract the interests of chemists and industrialists. In addition, the presence of 4-hydroxycoumarin and N,N-dimethylbarbituric acid scaffolds as important biological and pharmacological fragments in the chemical structure of products makes them more significant for pharmacologists, and their biological and pharmacological activities could be evaluated in future.