The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 26, 1991
Filed:
Nov. 24, 1989
Michael Meier, Frankfurt am Main, DE;
Gunther Semler, Kelkheim, DE;
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
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.