Process for removing sulfonyl groups from benzimidazole isomers
US4463181A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 21, 1983 |
| Grant date | Jul 31, 1984 |
| Priority date | — |
| Expiry date | Mar 21, 2003 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D235/30
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
This invention discloses a process for removing a sulfonyl group from the 1-position of a benzimidazole to allow conversion of 2-amino-1,5-substituted-benzimidazole compounds into 2-amino-1,6-substituted-benzimidazole compounds. The 5-isomer is reacted with an alkali metal hydroxide or carbonate in an inert aqueous organic solvent system. The reaction is acidified to precipitate the base and form the intermediate benzimidazole tautomer. The intermediate is then reacted with a sulfonyl acylating agent or a haloalkyl isothiocyanate to form a mixture of 2-amino-1,5(6)-substituted-benzimidazole compounds. This invention also discloses the same process for removing a sulfonyl group from the 1-position of a benzimidazole to allow conversion of 2-amino-1,6-substituted-benzimidazole compounds into 2-amino-1,5-substituted-benzimidazole compounds.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.