Copper (II) complex supported on the surface of magnetic nanoparticles modified with S-benzylisothiourea (Fe3O4@SiO2-SMTU-Cu): A new and efficient nanomagnetic catalyst for the synthesis of quinazolines and amides

A novel magnetically recoverable copper catalyst was successfully fabricated through the immobilization of Cu(NO3)2 on the surface of silica-coated magnetic Fe3O4 nanoparticles (Fe3O4@SiO2) functionalized with S-benzylisothiourea ligand. The Fe3O4@SiO2-SMTU-Cu nanocomposite was fully characterized by FT-IR spectroscopy, SEM, EDX, TGA, XRD, VSM, ASS and ICP-OES techniques. The Fe3O4@SiO2-SMTU-Cu nanocomposite exhibited high catalytic activity in the synthesis of biologically active quinazolines and amides. According to our research on the literature, this is the first report in the use of magnetic copper nanocatalyst for the synthesis of quinazolines. In this paper, we also presented tentative mechanisms for the synthesis of quinazolines and amides in the presence of catalytic amount of Fe3O4@SiO2-SMTU-Cu nanocomposite. This method gives notable advantages such as easy separation of the catalyst by external magnetic field; excellent yields, short reaction times, nontoxic metal catalyst, and simplicity of operation make this method a facile tool for the synthesis of quinazolines and amides. Fe3O4@SiO2-SMTU-Cu as a new and efficient nanomagnetic catalyst for the synthesis of quinazolines and amides.