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.