In this investigation, acetic acid functionalized pyridinium salt, namely 1-(carboxymethyl)pyridiniumiodide {[cmpy]I}, has been introduced as reusable catalyst for green, simple and efficient synthesis of6-amino-4-(4-methoxyphenyl)-5-cyano-3-methyl-1-phenyl-1,4-dihydropyrano[2,3-c]pyrazoles by theone-pot tandem four-component condensation reaction of aryl aldehydes with ethyl acetoacetate, mal-ononitrile and hydrazine hydrate at 100◦C under solvent-free conditions. Additionally,1H and13C 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.
