1-(2,5-Dichlorophenyl)-3-methyl-4-((o-nitrophenyl)azo)-2-pyrazolin-5-one 2-Pyrazolin-5-one, 1-(2,5-dichlorophenyl)-3-methyl-4-((o-nitrophenyl)azo)- 26858-84-4 29330-49-2 EINECS 249-564-1