Meglumine promoted one-pot, four-component synthesis of pyranopyrazole derivatives

Abstract

Meglumine, a bio-based chemical, was demonstrated to be a highly efficient and reusable catalyst for the synthesis of a series of pyranopyrazole derivatives via a one-pot, four-component reaction of carbonyl compound or isatin, hydrazine hydrate, malononitrile, and β-keto ester in EtOH–H2O. The catalyst was found to work extremely for aldehydes, ketones or isatins at room temperature to give the corresponding dihydropyrano[2,3-c]pyrazole or spiro[indoline-3,4′-pyrano[2,3-c]pyrazole] derivatives in high yields. The salient features of this new methodology are broad substrate scope, room temperature reaction conditions, short reaction times, high yields, easy work-up process, reusability of catalyst, and the absence of hazardous organic solvents.