Synthesis and Characterization of Some Pyrazole Derivatives of 1,5-Diphenyl-1H-pyrazole-3,4-dicarboxylic Acid

Compound of 4-(ethoxycarbonyl)-1,5-diphenyl-1H-pyrazole-3-carboxylic acid 2 was obtained from the reaction of ethyl 4,5-dioxo-2-phenyl-4,5-dihydrofuran-3-carboxylate and 1-benzylidene-2-phenylhydrazine. A number of substitute pyrazole dicarboxylic acid derivatives (4, 5a-c, 6, 7, 8, 9a-m, 10, 11, 12, 13, 14) were synthesized from 1,5-diphenyl-1H-pyrazole-3,4-dicarboxylic acid 3 which was prepared from basic hydrolysis of 2. Structures of synthesized compounds were characterized by H-1 NMR, C-13 NMR, Mass, FTIR, and elemental analysis.