Process for preparing 5,6-dihydroxyindole
US4595765A · kind A · utility
7Cited by
5References
8Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Oct 18, 1985 |
| Grant date | Jun 17, 1986 |
| Priority date | — |
| Expiry date | Oct 18, 2005 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D209/08
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
5,6-Dihydroxyindole is prepared by the catalytic reductive cyclization of 4,5-dihydroxy-2,.beta.-dinitrostyrene in a single step using hydrogen with a palladium, platinum or rhodium catalyst in a polar hydroxylic reaction system. No reaction byproducts or only a single reaction byproduct are produced. The 4,5-dihydroxy-2,.beta.-dinitrostyrene intermediate can be prepared by the chemoselective debenzylation of 4,5-dibenzyloxy-2,.beta.-dinitrostyrene using trifluoroacetic acid. 5,6-Dihydroxyindole is a useful component in hair dye formulations and as an intermediate in the synthesis of melanin.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.