Process for the preparation of UV filter substances

US6593476B2 · kind B2 · utility

Assignee

• MERCK PATENT GESELLSCHAFT MIT BESHRANK TER HAFTUNG · DE

Inventors

• Ulrich Heywang · Darmstadt, DE
• Michael Schwarz · Pocking, DE
• Frank Pflucker · Darmstadt, DE

Key dates

• Filing date: Jun 25, 2001
• Grant date: Jul 15, 2003
• Expiry date: Jun 25, 2021

Classification

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

Abstract

The present invention relates to a preparation process for 2-arylbenzimidazolesulfonic acids of the formula I: Ar is a substituted or unsubstituted phenyl or naphthyl radical and R is a C1-8-alkyl or C1-8-alkoxy radical. n is 1-4, m is 1-3 and o is 0-2. o-phenylenediamine is reacted in the presence of oleum with an arylcarboxylic acid or an arylcarboxylic acid derivative. Compounds prepared in this way can be used as UV filters, and as components in cosmetic compositions.