A Novel One-Pot, Three-ComponentSynthesis of Dialkyl 5-(Alkylamino)-1-aryl-1H-pyrazole-3,4-dicarboxylates

A novel, one-pot, and three-component synthesis of dialkyl 5-(alkylamino)-1-aryl-1 H-pyrazole-3,4-dicarboxylates is described.The reactive 1:1 zwitterionic intermediate, formed by the additionof isocyanides to dialkyl acetylenedicarboxylates, was trapped byhydrazinecarboxamides to afford the title compounds in good yields.