trisodium 8-[[4-[(4-aminophenyl)azo]-6-sulphonatonaphthyl]azo]-5-[(2-hydroxy-6-sulphonatonaphthyl)azo]naphthalene-2-sulphonate

2-(4-Aminophenylamino)-2-oxoacetic acid diazo, and 5-Aminonaphthalene-2-sulfonic acid?coupling, again diazo, and 5-Aminonaphthalene-2-sulfonic acid?coupling, product to diazo, and 6-Hydroxynaphthalene-2-sulfonic acid?coupling, and then 2-(4-Aminophenylamino)-2-oxoacetic acid hydrolysis base.

blue to the navy. Soluble in water for dark purple, slightly soluble in alcohol. The strong sulfuric acid for gray, diluted for purple. The dye solution to join strong hydrochloric acid have sauce red precipitate; Add thick sodium hydroxide solution have sauce red precipitate.