1H-Pyrazole-3-carboxylic acid, 4,5-dihydro-4-((2-nitrophenyl)azo)-5-oxo-1-phenyl-, ethyl ester 251654-29-2 5-Hydroxy-4-((o-nitrophenyl)azo)-1-phenylpyrazole-3-carboxylic acid, ethyl ester 68213-91-2 EINECS 269-274-9 Ethyl 4,5-dihydro-4-((2-nitrophenyl)azo)-5-oxo-1-phenyl-1H-pyrazole-3-carboxylate