Fe3O4@urea/HITh-SO3H as an efficient and reusable catalyst for the solvent-free synthesis of 7-aryl-8H-benzo[h]indeno[1,2-b]quinoline-8-one and indeno[2′,1′:5,6]pyrido[2,3-d]pyrimidine derivatives

Abstract

In this study, Fe3O4@urea/HITh-SO3H MNPs as a new, efficient, and recyclable solid acid magnetic nanocatalyst was synthesized and characterized using various methods including Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry, energy-dispersive X-ray spectroscopy, and X-ray powder diffraction. After the characterization of this new magnetic nanocatalyst, it was efficiently utilized for the promotion of the one-pot synthesis of 7-aryl-8H-benzo[h]indeno[1,2-b]quinoline-8-one and indeno[2′,1′:5,6]pyrido[2,3-d]pyrimidine derivatives via three-component reaction of the 1,3-indanedione, aldehyde, and 1-naphthylamine/1,3-dimethyl-6-aminouracil under solvent-free conditions at 80°C. The procedure gave the desired heterocyclic structures in high-to-excellent yields and short reaction times. Also because of the magnetic nature of the nanocatalyst, it can be separated with an external magnetic field and reused at least six runs without any considerable decrease in the catalytic behavior.