Benzenesulfonic acid,4-(4,5-dihydro-4-((2-hydroxy-5-nitrophenyl)azo)-3-methyl-5-oxo-1H-pyrazol-1-yl)-,monosodium salt, Benzenesulfonic acid,4-(4,5-dihydro-4-(2-(2-hydroxy-5-nitrophenyl)diazenyl)-3-methyl-5-oxo-1H-pyrazol-1-yl)-,sodium salt (1:1), Sodium p-(4,5-dihydro-4-((2-hydroxy-5-nitrophenyl)azo)-3-methyl-5-oxo-1H-pyrazol-1-yl)benzenesulphonate, EINECS 228-811-7, 2-Pyrazolin-5-one,4-((2-hydroxy-5-nitrophenyl)azo)-3-methyl-1-(p-sulfophenyl)-,sodium salt,