1-Naphthalenesulfonic acid, 7-(4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl)-3-hydroxy- 7-(4,5-Dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl)-3-hydroxy-1-naphthalenesulfonic acid 7-(4,5-Dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl)-3-hydroxynaphthalene-1-sulphonic acid 75476-93-6 EINECS 278-218-2