4-Chloro-3-(3-methyl-5-oxo-2-pyrazolin-1-yl)benzenesulfonic acid 4-Chloro-3-(3-methyl-5-oxo-2-pyrazolin-1-yl)benzenesulphonic acid 88-76-6 Benzenesulfonic acid, 4-chloro-3-(3-methyl-5-oxo-2-pyrazolin-1-yl)- (8CI) Benzenesulfonic acid, 4-chloro-3-(4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl)- EINECS 201-858-0 NSC 26425