Process for the preparation of benzimidazolones

US5003079A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Michael Meier · Frankfurt am Main, DE
• Gunther Semler · Kelkheim, DE

Key dates

• Filing date: Nov 24, 1989
• Grant date: Mar 26, 1991
• Expiry date: Nov 24, 2009

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D235/26
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Process for the preparation of benzimidazolones of the formula (1) ##STR1## in which R.sub.1 and R.sub.2 are identical or different and denote hydrogen or halogen atoms, or alkyl(C.sub.1 -C.sub.4), alkoxy(c.sub.1 -C.sub.4), trifluoromethyl, phenyl, phenoxy or nitro groups, by reacting o-phenylenediamines of the formula (2) ##STR2## in which R.sub.1 and R.sub.2 have the meaning given, with phosgene in water in the presence of an alkali metal base or alkaline earth metal base or a salt of an alkali metal hydroxide or alkaline earth metal hydroxide and a weakly inorganic or organic acid or a mixture of such salts or a suitable buffer system, at a pH of about 6 to about 12, and at a temperature of about 20.degree. to 100.degree. C.