Nickel ferrite as a recyclable nanocatalyst for synthesis of novel highly substituted 1,4-dihydropyrano[2,3-c]pyrazole derivatives

Highly substituted 1,4-dihydropyrano[2,3-c]pyrazole derivatives were synthesized by four-component reaction of aromatic aldehydes, malononitrile, ethyl acetoacetate and various phenylhydrazine, using nickel ferrite as a recyclable nanocatalyst by a grinding method under solvent-free and thermal conditions. The reaction has the advantages of good yields, less pollution, ease of separation of the desired products, and being environment-friendly. A possible mechanism for this reaction was proposed.