Plant protecting and regulating compositions – Plant growth regulating compositions – Organic active compound containing
Reexamination Certificate
1998-05-13
2001-10-30
Rotman, Alan L. (Department: 1612)
Plant protecting and regulating compositions
Plant growth regulating compositions
Organic active compound containing
C546S288000, C546S301000, C546S303000, C546S275400
Reexamination Certificate
active
06310006
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to certain novel trisubstituted 3,5-difluoropyridines, to the preparation of such compounds, to herbicidal compositions containing such compounds, and to a method of combating undesired plant growth using such compounds.
Pyridines and their derivatives have many uses in the pharmaceutical area as well as in agriculture (herbicides, fungicides, acaricides, anthelmintics, bird repellents), as reagents, intermediates and chemicals for the polymer and textile industry.
The broad generic formula of the International patent application WO 96/06096 embraces fluorinated 2-azolyl-5-aryloxypyridines.
Similar 2-aryl-5-aryloxypyridines are disclosed by EP 0 723 960. The co-pending U.S. patent application Ser. No. 08/680,193 (Case 33,272) discloses 2-thienyl-5-aryloxypyridines. However, there is no hint to 3,5-difluoropyridines in any of these documents.
The co-pending U.S. patent application Ser. No. 08/688,591 (Case 33,273) discloses 2,6-bisaryloxy-3,5-difluoropyridines.
Although many of the known compounds show considerable activity against various weeds, they are not completely satisfying with regard to their selectivity or because of their persistence.
The compounds according to the present invention combine high herbicidal activity with the necessary selectivity and enhanced soil degradation.
SUMMARY OF THE INVENTION
We have now found that, surprisingly, 2-aryloxy-6-aryl-3,5-difluoropyridines show excellent herbicidal activity at low dosages combined with higher selectivity in crops than those disclosed in the aforementioned patent applications.
Accordingly, the present invention provides novel compounds of the general formula I
wherein
A represents an optionally substituted aryl group or an optionally substituted 5- or 6-membered nitrogen-containing heteroaromatic group or a difluorobenzodioxolyl group;
B represents an optionally substituted phenyl or thienyl group;
R represents a halogen atom or an optionally substituted alkyl, alkenyl, alkinyl, alkoxy, alkoxyalkyl, alkylthio, alkylamino, dialkylamino, alkylsulphinyl, alkylsulphonyl group or a nitro, cyano, hydroxy, amino, haloalkyl, haloalkoxy, haloalkylthio or SF
5
group, and,
X represents an oxygen or a sulfur atom;
and the agronomically acceptable salts or N-oxides thereof.
The new compounds show an excellent selective herbicidal activity in certain crops, such as maize and rice, and enhanced soil degradation.
It is another object of the invention to provide methods for controlling undesired plant growth by contacting said plants with a herbicidally effective amount of the new compounds.
It is another object of the invention to provide selective herbicidal compositions containing the new compounds as active ingredients.
It is another object of the invention to provide new processes for the preparation of the new compounds.
Those and other objects and features of the invention will become more apparent from the detailed description set forth hereinbelow.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
It has surprisingly been found that the novel compounds of formula I in which R, A, B and X have the meaning given above for formula I, and the agronomically acceptable salts or N-oxides thereof, show an excellent herbicidal activity against a broad range of weeds.
An aryl group as substituent or part of other substituents or in the definition of A is suitably an optionally substituted phenyl group. Within the definition of A the 5- or 6-membered heteroaryl group comprises optionally substituted 5- or 6-membered heterocycles containing one or more nitrogen and/or oxygen and/or sulfur atoms, 1 to 3 nitrogen atoms being preferred. Examples of such groups are pyrazolyl, imidazolyl, triazolyl, tetrazolyl, pyridyl, pyrazinyl, pyrimidyl, pyridazinyl, isoxazolyl, isothiazolyl and triazinyl groups. As far as A is concerned the definition “aryl” does also include bicyclic systems which consist of a benzene ring fused with a 5- or 6-membered heterocyclic ring as defined above and in turn the 5- or 6-membered heterocycles may be fused with a benzene ring. Another preferred embodiment of A is a difluorobenzodioxolyl group of formula
A preferably represents a phenyl, pyridyl or pyrazolyl group being substituted by one or more of the same or different substituents selected from halogen atoms, alkyl groups, alkoxy groups, cyano groups, haloalkyl groups, haloalkoxy groups, alkylthio groups, haloalkylthio groups and SF
5
groups, in particular wherein A has a substituent in the meta-position relative to the point of attachment. Most preferred wherein A is meta-substituted by a fluorine or chlorine atom, or a trifluoromethyl, trifluoromethoxy or difluoromethoxy group.
B preferably represents a phenyl or thienyl group being substituted by one or more of the same or different substituents selected from halogen atoms, alkyl groups, alkoxy groups, cyano groups, haloalkyl groups, haloalkoxy groups, alkylthio groups, haloalkylthio groups, alkylsulfonyl and SF
5
groups, in particular wherein if B is a phenyl group it has a substituent in the para-position relative to the point of attachment. Most preferred wherein B is a phenyl group being para-substituted by a fluorine or chlorine atom, or a trifluoromethyl, trifluoromethoxy or difluoromethoxy group.
R represents preferably a halogen atom or an optionally substituted alkyl, alkenyl, alkoxy, alkoxyalkyl, alkylthio group or a nitro or cyano group.
X is preferably an oxygen atom.
Generally, if any of the above mentioned moieties comprises an alkyl, alkenyl or alkynyl group, such groups, unless otherwise specified, may be linear or branched and may contain 1 to 6, preferably 1 to 4, carbon atoms. Examples of such groups are methyl, ethyl, propyl, vinyl, allyl, propargyl, isopropyl, butyl, isobutyl and tertiary-butyl groups. The alkyl portion of a haloalkyl, haloalkoxy, haloalkylthio, alkylthio or alkoxy group suitably has from 1 to 4 carbon atoms, preferably 1 or 2 carbon atoms. The number of carbon atoms in the alkoxyalkyl, alkoxyalkoxy or dialkoxyalkyl groups is up to 6, preferably up to 4, e.g. methoxymethyl, methoxymethoxy, methoxyethyl, ethoxymethyl, ethoxyethoxy, dimethoxymethyl.
“Halogen” means a fluorine, chlorine, bromine or iodine atom, preferably fluorine, chlorine or bromine. Haloalkyl moieties of any groups within the definitions used herein and as such can contain one or more halogen atoms. Haloalkyl, haloalkoxy and haloalkylthio are preferably mono-, di-, tri- or perfluoroalkyl, -alkoxy and -alkylthio, especially trifluoromethyl, pentafluoroethyl, trifluoromethoxy, difluoromethoxy, difluoromethylthio, trifluoromethylthio or 2,2,2-trifluoroethoxy groups.
When any groups are designated as being optionally substituted, the substituent groups which are optionally present may be any of those customarily employed in the modification and/or development of pesticidal compounds and are especially substituents that maintain or enhance the herbicidal activity associated with the compounds of the present invention, or influence persistence of action, soil or plant penetration, or any other desirable property of such herbicidal compounds.
There may be one or more of the same or different substituents present in each part of the molecules. In relation to moieties defined above as comprising an optionally substituted alkyl group, including alkyl parts of haloalkyl, alkoxy, alkylthio, haloalkoxy, alkylamino and dialkylamino groups, specific examples of such substituents include phenyl, halogen atoms, nitro, cyano, hydroxyl, C
1-4
-alkoxy, C
1-4
-haloalkoxy and C
1-4
-alkoxycarbonyl groups.
In relation to moieties defined above as comprising an optionally substituted aryl or heteroaryl group, optional substituents include halogen, especially fluorine, chlorine and bromine atoms, and nitro, cyano, amino, hydroxy, phenoxy, C
1-4
-alkyl, C
1-4
-alkoxy, C
1-4
-haloalkyl, C
1-4
-haloalkenyl, C
1-4
-haloalkoxy, C
1-4
-haloalkylthio, C
1-4
-alkylsulfonyl and halosulfanyl groups such as SF
5
. In the case of phenyl-groups 1 to 5 substituents may suitably be empl
Baltruschat Helmut S.
Maier Thomas
Scheiblich Stefan
American Cyanamid Company
Costello, Jr. Charles F.
Rotman Alan L.
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