4-(3-Methyl-5-oxo-2-pyrazolin-1-yl)benzenesulphonic acid 74583-53-2 89-36-1 AI3-08532 Benzenesulfonic acid, 4-(4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl)- Benzenesulfonic acid, p-(3-methyl-5-oxo-2-pyrazolin-1-yl)- (8CI) EINECS 201-901-3 NSC 26429 Pyrazoline G