Fe3O4@SiO2-APA/OCA-Cucl2 nanocomposite: an efficient and reusable heterogenous catalyst for three-component synthesis of thiazole derivatives

The widespread use of thiazole derivatives in medicinal and medical chemistry and the presence of the thiazole ring in the structure of critical biological molecules increased the popularity of these compounds among synthetic chemists. In this paper, we fabricated a nanomagnetic copper catalyst via the immobilization of CuCl2 on the surface of Fe3O4@SiO2-APA/OCA ligand by simple methods. We characterized its structure using spectroscopic techniques such as FT-IR, SEM, TEM, VSM, TGA, XRD, ICP-OES, EDX, and elemental mapping techniques. The Fe3O4@SiO2-APA/OCA-CuCl2 nanocomposite showed high catalytic activity in the preparation of 2,4-substituted thiazoles through multicomponent reactions of different phenylmethanamines, 2-phenylacetaldehyde derivatives and S8 (as sulfur source) under oxygen molecular and mild conditions. This method has several outstanding features, which can be mentioned as follows: performing the reaction in green solvent under mild conditions in less than four h, synthesis of thiazole products with very high yields, high activity of the Fe3O4@SiO2-APA/OCA-CuCl2 catalyst, simple separation of the nanomagnetic catalyst from the mixture using an external magnet, and the high reusability of the Fe3O4@SiO2-APA/OCA-CuCl2 catalyst.