Expeditious, Four-Component Synthesis of 1,4-Dihydropyrano[2,3-c]Pyrazole Derivatives Catalyzed by Trichloroacetic Acid or Ceric Sulfate

Two efficient and convenient procedures for the synthesis of 6-amino-3-methyl-1,4-diphenyl-1,4-dihydropyrano[2,3- c]pyrazole-5-carbonitrile derivatives based on four-component reaction involving ethyl acetoacetate, phenylhydrazine, malononitrile, and various aromatic aldehydes using trichloroacetic acid or ceric sulfate as heterogeneous catalysts in excellent yields and short reaction times have been described.

1,4-Dihydropyrano[2,3-c]pyrazole derivatives, Four-component reaction, Trichloroacetic acid, Ceric sulfate, Heterogeneous catalysts