Process for preparing 1-amino-2-naphthol-4-sulphonic acid (amidol acid)

US4427601A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Erich Hammerschmidt · Bensberg, DE
• Horst Behre · Odenthal, DE
• Heinz U. Blank · Odenthal, DE
• Otto Lindner · Bensberg, DE

Key dates

• Filing date: Nov 5, 1982
• Grant date: Jan 24, 1984
• Expiry date: Nov 5, 2002

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C303/22
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The process for preparing 1-amino-2-naphthol-4-sulphonic acid by acidifying 3-oxo-4-hydroxyimino-1,2,3,4-tetrahydronaphthalene-1-sulphonic acid or its alkali metal salt in the presence of hydrogen sulphite is carried out in the presence of iron ions.