Process for the preparation of phenylene-bis-benzimidazole-tetrasulfonic acid disodium salt

US6730795B2 · kind B2 · utility

Assignee

• Symrise GmbH & Co. KG · DE

Inventors

• Ralf Bertram · Holzminden, DE
• Stephan Hillers · Holzminden, DE
• Oskar Koch · Oebisfelde, DE
• Harry Erfurt · Uslar, DE
• Gerald Reinders · Rinteln, DE

Key dates

• Filing date: Nov 27, 2001
• Grant date: May 4, 2004
• Expiry date: Nov 27, 2021

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D235/20
• WIPO field: Pharmaceuticals
• WIPO sector: Chemistry

Abstract

Phenylene-bis-benzimidazole-tetrasulfonic acid disodium salt which is largely free from impurities can be prepared by reacting o-phenylenediamine with terephthalic acid and chlorosulfonic acid in the presence of strong acids with a reaction time of 10 to 15 hours.