4-[3-(dihydroxymethyl)-4-[(3-methylphenyl)hydrazinylidene]-5-oxopyrazol-1-yl]benzenesulfonic acid;4-[3-(dihydroxymethyl)-4-[(4-methylphenyl)hydrazinylidene]-5-oxopyrazol-1-yl]benzenesulfonic acid;2-[2-[3-(dihydroxymethyl)-1-(4-methylphenyl)-5-oxopyrazol-4-ylidene]hydrazinyl]-4-[[4-(2-methylidenehydrazinyl)-6-(3-sulfophenyl)-1,3,5-triazin-2-yl]amino]benzenesulfonic acid;3-methyl-2-[(4-methylphenyl)hydrazinylidene]naphthalen-1-one