Process for preparing 2-(4-aminophenyl)-5-amino-benzimidazole and substituted derivatives
US4417056A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 11, 1982 |
| Grant date | Nov 22, 1983 |
| Priority date | — |
| Expiry date | Mar 11, 2002 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D235/18
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.