Design and Preparation of Copper(II)–Mesalamine Complex Functionalized on Silica-Coated Magnetite Nanoparticles and Study of Its Catalytic Properties for Green and Multicomponent Synthesis of Highly Substituted 4H-Chromenes and Pyridines

Abstract

In the present study, a green and ecofriendly nanocatalyst was synthesized through functionalization of 2,4,6-trichloro-1,3,5-triazine (TCT) and mesalamine on silica-coated magnetic nanoparticles (MNPs), then coordination with Cu2+ without agglomeration, consecutively. The silica-coated MNPs functionalized with the Cu(*II)–mesalamine complex was (Fe3O4@SiO2@NH2-TCT-mesalamine–Cu(II) MNPs) completely characterized by FT-IR, XRD, EDX, FESEM, TEM, VSM, TGA, and BET analyses. Afterward, the activity of the novel catalyst was investigated in the synthesis of chromene heterocycles, which were an important group of organic compounds. The activity of Fe3O4@SiO2@NH2-TCT-mesalamine–Cu(II) MNPs as a high-performance heterogeneous nanocatalyst was evaluated for the synthesis of 2-amino-4-aryl-6-(phenylthio)pyridine-3,5-dicarbonitriles and 2-amino-4H-chromenes via aromatic aldehydes, malononitrile, and enolizable C–H acids (resorcinol, 2-hydroxynaphthalene-1,4-dione, and benzenethiol) in ethanol under reflux conditions. Fe3O4@SiO2-TCT-mesalamine–Cu(II) could be quickly separated using an external magnet and reused nine times without a remarkable reduction of its catalytic activity.