1: o-tolidine-6,6'-disulfonic acid; 2-methoxy-4nitro-aniline With hydrogenchloride; sodium nitrite in water T=10°C; 1 h; 2: aceto-acetyl-amino-2-methoxy-benzene With sodium hydroxide; sodium acetate; acetic acid in water T=25 - 90°C; pH=6; 150 h;

T=250°C;

1: o-tolidine-6,6'-disulfonic acid; 1-amino-2-nitro-4-methylbenzene With hydrogenchloride; sodium nitrite in water T=10°C; 1 h; 2: 1-(N-phenylcarbamyl)propan-2-one With sodium hydroxide; sodium acetate; acetic acid in water T=25 - 90°C; pH=6; 2.5 h;

sulfuric acid T=105°C; man reduziert die entstandene Nitrosulfonsaeure elektrolytisch zur Hydrazo-sulfonsaeure und lagert diese mittels verd. Schwefelsaeure um;

sodium hydroxide; zinc man filtriert in Salzsaeure;