2-(3-Methyl-5-oxo-1-phenyl-2-pyrazolin-4-ylazo)benzoic acid

1-Phenyl-3-methyl-4-(2-carboxyphenylazo)-1H-pyrazol-5(4H)-one

2-[(4,5-dihydro-3-methyl-5-oxo-1-phenyl-1H-pyrazol-4-yl)azo]benzoic acid