Synonyms: 2,5-dichloro-4-[[2-(dibutylamino)-4-methyl-6-[[2-(4-sulphophenyl)ethyl]amino]-5-pyrimidinyl]azo]benzenesulphonic acid, sodium salt;Benzenesulfonic acid, 2,5-dichloro-4-2-(dibutylamino)-4-methyl-6-2-(4-sulfophenyl)ethylamino-5-pyrimidinylazo-, sodium salt;2,5-Dichloro-4-[[2-(dibutylamino)-4-methyl-6-[[2-(4-sulfophenyl)ethyl]amino]pyrimidine-5-yl]azo]benzenesulfonic acid/sodium,(1:x) salt