Preparation
5-Amino-2-(4-aminophenylamino)benzenesulfonic acid double nitriding, and 5-Aminonaphthalene-2-sulfonic acid and 8-Aminonaphthalene-2-sulfonic acid coupling, and double nitriding, and 7-Amino-4-hydroxynaphthalene-2-sulfonic acid (2 Moore) coupled.
