The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 16, 1989
Filed:
Oct. 04, 1985
Rolf Schurter, Binningen, CH;
Urs Siegrist, Mohlin, CH;
Hermann Rempfler, Ettingen, CH;
Peter Baumeister, Fluh, CH;
Ciba-Geigy Corporation, Ardsley, NY (US);
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.