Reaction of ethyl 4-[(E)-1-chloro-3-oxoprop-1-en-1-yl]-3,5-dimethyl-1H-pyrrole-2-carboxylate with hydrazines

Abstract

Ethyl 4-[(E)-1-chloro-3-oxoprop-1-en-1-yl]-3,5-dimethyl-1H-pyrrole-2-carboxylate reacted with substituted hydrazines in different solvents to give mixtures of regioisomeric 3- and 5-substituted pyrazoles. Conditions were found for selective formation of 1-aryl(alkyl)-5-(5-ethoxycarbonyl-2,4-dimethyl-1H-pyrrol-3-yl)-1H-pyrazoles.