Reactions of b-Aminoenones with Acetylhydrazine, Semicarbazide and Methoxycarbonylhydrazine. Synthesis of 1-Acetyl-, 1-Carboxamide- or Methyl 1-Carboxylated Pyrazole Derivatives

Abstract

Acetylhydrazine, semicarbazide and methoxycarbonylhydrazine react with p-aminoenones to give regioselectively the corresponding N-acetyl-or Ncarhoxypyrazole derivatives.The reaction are highly regioselective and occurs via 5-hydroxypyrazolines which in several case can be isolated and characterized.