4-Chloro-3-(3-methyl-5-oxo-2-pyrazolin-1-yl)benzenesulfonic acid 88-76-6 Benzenesulfonic acid, 4-chloro-3-(3-methyl-5-oxo-2-pyrazolin-1-yl)- Benzenesulfonic acid, 4-chloro-3-(4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl)- NSC26425