Process for preparing 2,4-dichloro-3-alkyl-6-nitrophenols
US5136109A · kind A · utility
1Cited by
4References
21Claims
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Key dates
| Filing date | May 29, 1991 |
| Grant date | Aug 4, 1992 |
| Priority date | — |
| Expiry date | May 29, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C201/16
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
2-4-Dichloro-3-alkyl-6-nitrophenols which are useful as intermediate of cyan couplers in color photography are prepared by sulfonating 4-chloro-3-alkyl-phenols to obtain 5-chloro-4-alkylhydroxybenzenesulfonic acids, chlorinating the acids in an aqueous phase to obtain 3,5-dichloro-4-alkyl-2-hydroxybenzenesulfonic acids and nitrating the sulfonic acids.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.