C.I. Acid Yellow 17

Lissamine fast yellow (acid form) is an arenesulfonic acid that is 2,5-dichloro-4-(pyrazol-1-yl)benzene-1-sulfonic acid in which the pyrazole ring is substituted by methyl, (4-sulfophenyl)diazenyl and hydroxy groups at positions 3, 4, and 5 respctively. The disodium salt is the biological stain 'lissamine fast yellow'. It has a role as an allergen, a histological dye and a food colouring. It is a member of azobenzenes, a dichlorobenzene, a member of pyrazoles, an arenesulfonic acid and a heteroaryl hydroxy compound. It is a conjugate acid of a lissamine fast yellow(2-).