One-opt, four component synthesis of pyrano[2,3-c]pyrazoles catalyzed by [VO(TPPA)]SO3H

In the past decades, metallophthalocyanines (MPcs) employed as the efficient biomimetic catalysts with thermal and chemical stability and easy access.1-2 In addition, poor solubility of metallophthalocyanines in common organic solvents can be considered as the most prominent point in their applications as the heterogeneous catalysts. In this regard, vanadium-oxo tetrapyridinoporphyrazine sulfonic acid was synthesized and fully characterized. Pyrazole derivatives are the significant kind of heterocyclic compounds that feature in several pharmaceutical targets and natural products of medicinal interest. Dihydropyrano[2,3-c]pyrazole derivatives have showed a wide variety of biological activities counting anticancer, antimicrobial, anti-inflammatory, insecticidal, and molluscicidal activities.In continuation of our efforts to synthesize of novel catalysts in the synthesis of multicomponent reactions, we wish to report the synthesis of vanadium-oxo tetrapyridinoporphyrazine sulfonic acid [VO(TPPA)]SO3H as an efficient catalyst for the synthesis of dihydropyrano[2,3-c]pyrazole through the condensation reaction of aryl aldehydes, ethyl acetoacetate, malononitrile, and phenyl hydrazine under solvent free conditions at 100° C (Scheme 1).

Keywords:

Metallophthalocyanines (MPcs) , Vanadium-oxo tetrapyridinoporphyrazine [VO(TPPA)]SO3H , Dihydropyrano[2 , 3-c]pyrazole.