Preparation
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?and where did 4-Hydroxynaphthalene-1-sulfonic acid?coupling, and then 2-(4-Aminophenylamino)-2-oxoacetic acid hydrolysis base.
