A novel nanomagnetic solid acid catalyst for the synthesis of new functionalized bis-coumarin derivatives under microwave irradiations in green conditions

摘要

In this study, a novel, green, environmentally friendly and magnetically heterogeneous catalyst based on the immobilization of sulfosalicylic acid onto Fe3O4 nanoparticles (Fe3O4@sulfosalicylic acid MNPs) is reported. The bis-coumarin analogs were synthesized in high yield using the reaction of 1 equivalent of aryl aldehydes with 2 equivalents of 4-hydroxycoumarin in water under microwave irradiation conditions. Scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, thermogravimetric analysis, dynamic light scattering, vibrating sample magnetometry, Fourier transform infrared spectroscopy, UV-visible absorption, and Brunauer-Emmett-Teller (BET) techniques confirmed the successful synthesis of the catalyst. The main attractive characteristics of the presented green protocol are very short reaction times (10-15 min), excellent yields, and the avoidance of hazardous or toxic reagent and solvents. Thermal durability, easy separation, and high reusability are important advantages of the new catalyst in comparison to other catalysts.