Synthesis of some substituted pyrazole-3-carboxylic acids with possible hypoglycemic and antimicrobial activity

Condensation of delta-unsaturated 1.3-diketoesters (1) with 4-substituted arylhydrazines (2) or benzenesulphonyl-hydrazine (8) led to 1-aryl-3-ethoxycarbonyl-5-[alpha-substituted styryl]-pyrazoles (3), and 1-benzenesulphonyl-3-ethoxycarbonyl-5-styryl pyrazole (9). Potassium permanganate oxidation of 3 gave 5-acetyl (or benzoyl)-1-aryl-3-ethoxycarbonyl pyrazoles (6) which on hydrolysis gave the corresponding carboxylic acids (7). Hydrolysis of 3 gave the corresponding acids 4 which on treatment with thionyl chloride followed by ammonia afforded the corresponding carboxamides 5.