Synonyms: 2-Pyrazolin-5-one,3-(p-nitroanilino)-1-(2,4,6-trichlorophenyl)- (6CI,7CI,8CI);1-(2,4,6-Trichlorophenyl)-3-p-nitroanilino-2-pyrazolin-5-one;1-(2,4,6-Trichlorophenyl)-3-p-nitroanilino-2-pyrazoline-5-one;3-(4-Nitroanilino)-1-(2,4,6-trichlorophenyl)-5-pyrazolone; NSC 166498