Nitrogen‐Doped Graphene Oxide as a Sustainable Carbonaceous Catalyst for Greener Synthesis: Benign and Solvent‐free Synthesis of Pyranopyrazoles

Abstract

AbstractThe development of benign strategies using the greener catalytic system is one of the prime tasks to improvise the greenness and sustainability in the synthesis of bioactive molecules. In the present work, a straightforward and sustainable methodology for the one‐pot synthesis of dihydropyrano[2,3‐c] pyrazole has been developed using nitrogen‐doped graphene oxide (NGO) as a solid carbocatalyst under neat condition. The presence of high‐density different types of nitrogen on the basal plane and the edges of the graphitic surface renders excellent active alkali sites and make it as a carbonaceous catalyst for the synthesis of a wide range of pyranopyrazoles with excellent yield. Present carbonaceous NGO catalysis the formation of pyranopyrazoles from diverse aldehydes and ketones under a solvent‐free simple grinding condition that avoids chromatographic purifications. In this benign multicomponent synthesis, the NGO is highly stable and reusable without any loss in its catalytic activity even after eight successive reuses, which strongly enlighten the sustainable nature of the catalyst. Further analytical studies of the reused catalyst confirm the stability of the catalyst even after several reuses. The NGO catalyst paves a path for the development of sustainable nitrogen‐based carbocatalyst for the benign multicomponent synthesis of bioactive molecules.