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[2,3c]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.