Synonyms: 5-Benzoxazolesulfonic acid, 2-(2-(1,5-dihydro-3-methyl-5-oxo-1-(4-sulfophenyl)-4H-pyrazol-4-ylidene)ethylidene)-3-ethyl-2,3-dihydro-;4-(2-(3-Ethyl-5-sulfo-2(3H)-benzoxazolylidene)ethylidene)-3-methyl-1-(4-sulfophenyl)-2-pyrazolin-5-one;2-((1,5-Dihydro-3-methyl-5-oxo-1-(4-sulphophenyl)-4H-pyrazol-4-ylidene)ethylidene)-3-ethyl-2,3-dihydrobenzoxazole-5-sulphonic acid;5-Benzoxazolesulfonic acid, 2-((1,5-dihydro-3-methyl-5-oxo-1-(4-sulfophenyl)-4H-pyrazol-4-ylidene)ethylidene)-3-ethyl-2,3-dihydro-;(2Z)-3-ethyl-2-{(2E)-2-[3-methyl-5-oxo-1-(4-sulfophenyl)-1,5-dihydro-4H-pyrazol-4-ylidene]ethylidene}-2,3-dihydro-1,3-benzoxazole-5-sulfonic acid