A design for convenient and greener root towards one-pot multi-component synthesis of substituted pyrano-dichromeneo-dione and chromeno-pyrido-pyrimidinone derivatives using rice husk based heterogeneous catalyst

In this work, a convenient and greener procedure for synthesizing substituted pyrano-dichromeno-dione and substituted chromeno-pyrido-pyrimidinone derivatives were explored using Sulphonated Rice Husk (SRH) as a novel bio-degradable, greener, heterogeneous catalyst. We designed an efficient pseudo three-component synthetic method for 7-aryl/heteroaryl substituted pyranodichromene-6, 8-dione and 7-aryl/heteroaryl substituted chromeno[4, 3-d]pyrido[1, 2-a]pyrimidinone derivatives using this greener catalyst (SRH) under reasonable reaction condition. The fundamental features of this procedure are the operational simplicity, hassle-free recovery of product, and reusability of the catalyst with excellent product yield (up to 98%). The toxic metal-free catalyst was prepared conveniently, and characterized using different spectroscopic techniques, including Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX). Then the synthesized material was used for the greener synthetic target.