4-[4-(3-Ethyl-5-sulfo-2(3H)-benzoxazolylidene)-2-butenylidene]-3-methyl-1-(4-sulfophenyl)-2-pyrazolin-5-one

2-[4-[1,5-dihydro-3-methyl-5-oxo-1-(4-sulfophenyl)-4H-pyrazol-4-ylidene]-2-butenylidene]-3-ethyl-2,5-Benzoxazolesulfonic acid

2-[4-[[1,5-Dihydro-3-methyl-5-oxo-1-(4-sulfophenyl)-4H-pyrazol]-4-ylidene]-2-butenylidene]-3-ethyl-2,3-dihydro-5-benzoxazolesulfonic acid

2-[4-[1,5-dihydro-3-methyl-5-oxo-1-(4-sulphophenyl)-4H-pyrazol-4-ylidene]but-2-enylidene]-3-ethyl-2,3-dihydrobenzoxazole-5-sulphonic acid