Reaction of 1,4-Dianion of Methyl 2-Methyl 2-Thienyl Ketone N-Ethoxycarbonylhydrazone with Carboxylic Acid Derivatives and the Synthesis of Pyrazolotriazin-7-ones

Abstract

Pyrazoles and pyrazolotriazines are important materials for medicinal, agricultural and other studies.1-4 Diverse biological activities such as bactericidal, pesticidal, anticonvulsant, tuberculostatic, anti-inflammatory, etc., have been found to be associated with pyrazole derivatives. In recent years, several new methods for the preparation of pyrazole derivatives have been reported in the literatures.5-7 However, little attention has been directed to obtain 3-hetero substituted pyrazoles. Thus, we reported here the synthesis of some 3thiophen-2-yl-5-substituted pyrazoles by the reaction of butyl formate, methyl benzoate, ethyl benzoylacetate, methyl 3-chlorobenzoate, ethyl hexanoate, ethyl pyruvate, ethyl phenylglyoxylate, acetyl chloride and phenoxyacetyl chloride with dianion of methyl 2-thienyl ketone N-ethoxycarbonylhydrazone. Moreover, 1,4-dianion of N-monosubstituted hydrazones8 have received much attention as synthetic intermediates owing to their interesting reactivities and preparative significance.