Fe3O4@SiO2-Serine-Ni(II) nanocomposite: A novel end efficient magnetically reusable nanocatalyst for synthesis of heterocycles

Abstract

The synthesis of 3,4-dihydropyrimidin-2(1H)-ones and highly functionalized piperidines is an attractive challenge among synthetic chemists because these compounds are precious from a pharmacological and biological point of view. In this method, we want to show that the Fe₃O₄@SiO₂-Serine-Ni(II) catalyst in glycerol solvent is an efficient and environmentally friendly catalytic system for the preparation of a library of 3,4-dihydropyridine-2 (1H)-ones and highly functionalized piperidines. In these reactions, various substrates such as benzaldehydes with electron-donating and electron-withdrawing substituents, heterocyclic aldehydes, and amines were evaluated, and the desired products were synthesized with good to excellent yields in a very short period of time. The recovery tests showed that the Fe₃O₄@SiO₂-Serine-Ni(II) catalyst still has high efficiency and stability despite being reused 9 times. The structure, shape, stability and magnetic properties of the Fe₃O₄@SiO₂-Serine-Ni(II) catalyst were evaluated both in the fresh state and after recovery by a series of spectroscopic analyses such as FT-IR, VSM, TGA, XRD, SEM, TEM, EDX, ICP-OES and elemental mapping techniques. This method has the following features compared to previously reported methods: performing reactions in glycerol solvent (environmentally friendly) and synthesis of products with high efficiency in a short period of time, the feasibility of the catalytic system for a wide range of substrates, the use of a green and recoverable catalyst, and the high reusability of the catalyst.