Green approach for the synthesis of pyranopyrazoles and hexahydroquinoline- 3-carboxamides using unripe grape juice (verjuice) as catalyst

Unripe grape juice (verjuice) as a natural catalyst was successfully applied to perform the onepot reaction of aryl aldehydes, malononitrile, hydrazine hydrate and ethyl acetoacetate to synthesize pyranopyrazole derivatives in aqueous ethanol at room temperature in excellent yields. Furthermore, unripe grape juice catalyzed onepot synthesis of hexahydroquinoline3carboxamide derivatives by the fourcomponent reaction of arylaldehydes, dimedone, acetoacetanilide and ammonium acetate in high to excellent yield in ethanol at 70 ℃. The synthesized compounds were identified by FTIR, lt;sup gt;1 lt;/sup gt;H NMR and lt;sup gt;13 lt;/sup gt;C NMR spectroscopic techniques and elemental analysis. An environmentally benign procedure, short reaction time, high yields and biocompatible natural catalyst are some advantages of this research.