Patent · US Expired

2-phenylbenzimidazole-5-sulphonic acid from isolated 3,4-diaminobenzenesulphonic acid and use thereof in cosmetic preparations

US6888005B2 · kind B2 · utility

0Cited by

9References

6Claims

0Family size

Assignee

BAYER HEALTHCARE LLC · DE

Inventors

Gunter Rauchschwalbe · Leverkusen, DE
Herbert Emde · Cologne, DE
Wolfram Kissener · Neunkirchen, DE
Klaus-Christian Paetz · Burscheid, DE

Key dates

Filing date	Sep 16, 2003
Grant date	May 3, 2005
Priority date	—
Expiry date	Sep 16, 2023

Classification

Technology area (CPC A)Human Necessities
CPC primaryA61Q17/04
WIPO fieldPharmaceuticals
WIPO sectorChemistry

Abstract

A process for the preparation of 2-phenylbenzimidazole-5-sulphonic acid, characterized in that 3,4-diaminobenzenesulphonic acid is reacted at a pH between 4 and 7 in aqueous solution with 0.9 to 1.5 mol of benzaldehyde per mole of 3,4-diaminobenzenesulphonic acid and with 1.0 to 3.0 mol of SO2 per mole of 3,4-diaminobenzenesulphonic acid, or an agent which comprises 1.0 to 3.0 mol of SO2 per mole of 3.4-diaminobenzenesulphonic acid, is described.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.