Synthesis and characterization of some pyrazole derivatives of 1,5‐diphenyl‐1 H ‐pyrazole‐3,4‐dicarboxylic acid

Compound of 4‐(ethoxycarbonyl)‐1,5‐diphenyl‐1 H ‐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 , 5b , 5c , 6 , 7 , 8 , 9a , 9b , 9c , 9d , 9e , 9f , 9g , 9h , 9i , 9j , 9k , 9l , 9m , 10 , 11 , 12 , 13 , 14 ) were synthesized from 1,5‐diphenyl‐1 H ‐pyrazole‐3,4‐dicarboxylic acid 3 which was prepared from basic hydrolysis of 2 . Structures of synthesized compounds were characterized by 1 H NMR, 13 C NMR, Mass, FTIR, and elemental analysis. J. Heterocyclic Chem., (2010).