New Access to Pyrano[2,3-<i>c</i>]pyrazole-3-carboxylates via Domino Four-Component Reaction and Their Antimicrobial Activity

Abstract

A library of some novel classes of pyrano[2,3-c]pyrazole-3-carboxylates was synthesized by employing uncatalyzed domino four-component reaction using diethyloxaloacetate, hydrazine hydrate, aldehydes and malononitrile in refluxing of ethanol-acetic acid solvent systems. Series of domino reactions involving of pyrazolone formation, Michael addition, and Thorpe-Ziegler cyclization reaction managed to produce the cyclized products from moderate to excellent yield. This protocol provides a reliable, general and salient procedure for the title compound using a one-pot approach. Preliminary biological screening unveiled limited potentials of this class of compounds for antimicrobial lead compound due to its limited solubility properties.

Keywords

• four-component reactions
• pyrano[2,3-c]pyrazole-3-carboxylate
• diethyloxaloacetate