Catalytic application of 1-(carboxymethyl)pyridinium iodide on the synthesis of pyranopyrazole derivatives

Abstract

In this investigation, acetic acid functionalized pyridinium salt, namely 1-(carboxymethyl)pyridinium iodide {[cmpy]I}, has been introduced as reusable catalyst for green, simple and efficient synthesis of 6-amino-4-(4-methoxyphenyl)-5-cyano-3-methyl-1-phenyl-1,4-dihydropyrano[2,3-c]pyrazoles by the one-pot tandem four-component condensation reaction of aryl aldehydes with ethyl acetoacetate, malononitrile and hydrazine hydrate at 100 °C under solvent-free conditions. Additionally, 1H and 13C NMR, mass, CHN analysis, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), thermal gravimetric analysis (TGA), differential thermal gravimetric (DTG), X-ray diffraction analysis (XRD), and calculation of crystallite size and inter planer distance of the catalyst have been investigated.