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:
Nov. 22, 1983
Filed:
Mar. 11, 1982
Jean-Marie Cognion, Saint-Genis-Laval, FR;
Pierre Durual, Vernaison, FR;
P.C.U.K. Produits Chimiques Ugine Kuhlmann, Courbevoie, FR;
Abstract
The invention concerns a process for the preparation of 2-(4-aminophenyl)-5-aminobenzimidazole and substituted derivatives by catalytic cycloreduction of starting material N-(4-nitrobenzoyl)-2,4-dinitroaniline or a substituted derivative by hydrogen gas. According to the invention, the starting material is treated in suspension in an aqueous solution of hydrochloric or phosphoric acid, the content (C) of starting material in said suspension ranging from 0.15 to 1.5 mole per liter and the molar ratio (A): acid/starting material being from 2 to 20. The process is carried out at a hydrogen pressure from 5 to 100 bars and a temperature (T) from 20.degree. to 150.degree. C. selected so that the product T.times.A.times.C is equal to or greater than 25. There is thereby obtained a product of excellent purity with very good yields.