Synonyms: 2-Pyrazolin-5-one,4-[(2-chloro-4-nitrophenyl)azo]-1-(2-hydroxyethyl)-3-methyl-, carbanilate(7CI); 2-Pyrazolin-5-one,4-[(2-chloro-4-nitrophenyl)azo]-1-(2-hydroxyethyl)-3-methyl-, carbanilate(ester) (8CI); 3H-Pyrazol-3-one,4-[(2-chloro-4-nitrophenyl)azo]-2,4-dihydro-5-methyl-2-[2-[[(phenylamino)carbonyl]oxy]ethyl]-(9CI);2-[4-[(2-Chloro-4-nitrophenyl)azo]-2,4-dihydro-5-methyl-3-oxo-3H-pyrazol-2-yl]ethylcarbanilate