1H-Pyrazole-3-carboxylic acid, 4,5-dihydro-1-(2-methyl-4-sulfophenyl)-5-oxo- 4,5-Dihydro-1-(2-methyl-4-sulphophenyl)-5-oxo-1H-pyrazole-3-carboxylic acid 4,5-Dihydro-5-oxo-1-(2-methyl-4-sulfophenyl)-1H-pyrazole-3-carboxylic acid 4-(3-Carboxy-5-oxo-2-pyrazolin-1-yl)-3-methylbenzenesulfonic acid 67939-25-7 EINECS 267-828-4