Synthesis of Pyrazolylthiazole and Pyrazolyl-1,2,4-Triazepine Derivatives

Abstract

In a multistep reaction, ( Z)-methyl 2-[( Z)-2-hydrazono-4-oxo-]-(3-substituted-1 H-pyrazol-5-yl)thiazolidin-5-ylidine)acetate, ( Z)-methyl-1-(2-methoxy-2-oxoethyl)-2-[( Z)-5-(2-methoxy-2-oxoethylidene)-4-oxo-3-(3-substituted-1 H-pyrazol-5-yl)-thiazolidin-2-ylidine)hydrazinecarboxylates and methyl 5-oxo-4-(3-substituted-1 H-pyrazol-5-yl)-3-thioxo-3,4,5,6-tetrahydro-2 H-1,2,4-triazepine-7-carboxylates have been formed in good yield from the reaction of N-(3-substituted-1 H-pyrazol-5-yl)-hydrazinecarbothioamides with dimethyl acetylenedicarboxylate. Explanations of these conversions involving nucleophilic reactions and condensations are presented.