Process for the preparation of fluorinated pyridine derivatives
US4831148A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 4, 1985 |
| Grant date | May 16, 1989 |
| Priority date | — |
| Expiry date | Oct 4, 2005 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D213/73
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
In accordance with a novel process, 2,3-difluoropyridines of formula I ##STR1## wherein X is halogen or trifluoromethyl, are prepared by diazotising a 3-amino-2-halopyridine of formula II ##STR2## wherein X is as defined for formula I and Y is bromine, chlorine or fluorine, in the presence of hydrogen fluroide, to give a 3-fluoro-2-halopyridine of formula III ##STR3## wherein X and Y are as defined for formula II, and treating resultant 3-fluoro-2-halopyridines of formula III, wherein Y is bromine or chlorine, with a fluorinating agent. The 2,3-difluoropyridines prepared by the novel process are valuable intermediates for the preparation of 2-[4-(3-fluoropyridin-2-yloxy)-phenoxy]propionic acid derivatives which are known as herbicides.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.