One-pot synthesis of pyrano[3,2-c]quinoline-2,5-dione derivatives by Fe3O4@SiO2-SO3H as an efficient and reusable solid acid catalyst

Abstract

In this study, Fe3O4@SiO2-SO3H was prepared as an efficient and reusable solid acid catalyst and its catalytic activity was considered in the synthesis of pyrano[3,2-c]quinoline-2,5-dione derivatives by the three-component reaction of 4-hydroxyquinolin-2(1H)-one, Meldrum’s acid and arylaldehydes under thermal solvent-free conditions at 70 °C. This catalytic system can be reused minimally for five times without any noticeable loss of activity. In addition, the characteristic analysis of Fe3O4@SiO2-SO3H, such as thermogravimetric analysis, Fourier-transform infrared spectroscopy, vibrating sample magnetometer, scanning electron microscope, and X-ray diffraction was performed.