25311-20-0 4-(4-((2,5-Dimethoxy-4-((2-(sulphooxy)ethyl)sulphonyl)phenyl)azo)-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl)benzenesulphonic acid Benzenesulfonic acid, 4-(4-((2,5-dimethoxy-4-((2-(sulfooxy)ethyl)sulfonyl)phenyl)azo)-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl)- EINECS 246-813-6