Pyridyl(oxy/thio)phenoxy compounds, herbicidal compositions and methods
申请人:The Dow Chemical Company
公开号:US04565568A1
公开(公告)日:1986-01-21
Certain novel pyridinyloxyphenoxy alkanoic acids, pyridinylthiophenoxy alkanoic acids, derivatives thereof and related compounds are described. More specifically, these novel compounds bear a fluorine substituent in the 3-position of the pyridinyl group and in the 5-position the substituent is selected from chlorine, CF.sub.3, CF.sub.2 Cl or CF.sub.2 H. These novel compounds exhibit surprising preemergent and postemergent activity in the control of grassy weeds.
Certain pyridyloxy or thio-phenoxy-propanoic acids or salts thereof
申请人:The Dow Chemical Company
公开号:US04678509A1
公开(公告)日:1987-07-07
Certain novel pyridinyloxyphenoxy alkanoic acids, pyridinylthiophenoxy alkanoic acids, derivatives thereof and related compounds are described. More specifically, these novel compounds bear a fluorine substituent in the 3-position of the pyridinyl group and in the 5-position the substituent is selected from chlorine, CF.sub.3, CF.sub.2 Cl or CF.sub.2 H. These novel compounds exhibit surprising preemergent and postemergent activity in the control of grassy weeds.
Process for the preparation of fluorinated pyridine derivatives
申请人:Ciba-Geigy Corporation
公开号:US04831148A1
公开(公告)日:1989-05-16
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.
2-Phenoxypropionic acid cyanamides of the formula ##STR1## have a useful selective herbicidal activity against weeds, preferably grass weeds, in crops of useful plants. In this formula R is hydrogen, C.sub.1 -C.sub.4 alkyl, C.sub.3 -C.sub.4 alkenyl, C.sub.3 -C.sub.4 alkynyl or C.sub.2 -C.sub.4 alkoxyalkyl, and T is a radical ##STR2## wherein A is oxygen or sulfur, X is fluorine, chlorine, bromine, iodine or trifluoromethyl, Y is hydrogen, fluorine, chlorine, bromine or trifluormethyl, and Z is nitrogen or the methine bridge.