Herbicidal 2-aryloxy-or 2-arylthio-6-arylpyrimidines

Details Herbicidal 2-aryloxy-or 2-arylthio-6-arylpyrimidines Herbicidal 2-aryloxy-or 2-arylthio-6-arylpyrimidines

1999-02-18

2001-11-06

Ford, John M. (Department: 1624)

Plant protecting and regulating compositions

Plant growth regulating compositions

Organic active compound containing

C504S243000, C504S238000, C504S235000, C504S229000, C504S230000, C504S221000, C544S295000, C544S296000, C544S182000, C544S219000, C544S055000, C544S003000, C544S309000, C544S310000, C544S316000, C544S313000, C544S314000, C544S315000, C544S317000, C544S318000

Reexamination Certificate

active

06313072

ABSTRACT:

BACKGROUND OF THE INVENTION
Pyrimidines 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 European patent application EP 0 723 960 A discloses for example herbicidal 2-aryl-6-aryloxypyrimidines.
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
The present invention provides novel 2-aryloxy- or 2-arylthio-6-arylpyrimidines of formula I
wherein
A represents an optionally substituted aryl group or an optionally substituted 5- or 6-membered heteroaromatic group or a difluorobenzodioxolyl group;
B represents a phenyl, pyridyl or thienyl group;
m represents an integer from 0 to 5;
R
1
represents a halogen atom or a cyano group or an optionally substituted alkyl, alkenyl, alkynyl, alkoxyalkyl, haloalkyl, alkoxy, haloalkoxy, alkylthio, alkylamino or dialkylamino group;
R
2
represents a hydrogen or halogen atom or a cyano group or an optionally substituted alkyl, alkoxy, haloalkyl or haloalkoxy group;
R
3
(or each R
3
) independently represents a halogen atom, an optionally substituted alkyl, alkenyl, alkynyl, alkoxy, alkoxyalkyl, alkoxyalkoxy, alkylthio, alkylsulphinyl, alkylsulphonyl group or a nitro, cyano, haloalkyl, haloalkoxy, haloalkylthio or SF
5
group, and X represents an oxygen or sulfur atom.
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.
These and other objects and features of the invention will be more apparent from the detailed description set forth hereinbelow, and from the appended claims.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
It has surprisingly been found that the novel 2-aryloxy- or 2-arylthio-6-arylpyrimidines of formula I
show considerable activity and high selectivity in certain crops, such as, in pre- and post-emergence applications on both broadleaf and grassy weed species.
In the definitions of the new compounds, an aryl group is suitably an optionally substituted phenyl or naphthyl 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, thienyl, pyridyl, pyrazinyl, pyrimidyl, pyridazinyl, isoxazolyl, isothiazolyl and triazinyl groups. A also includes bicyclic systems which consist of a benzene ring fused with a 5- or 6-membered heterocyclic ring as defined above. Another preferred embodiment of A is a difluorobenzodioxolyl group of formula
A preferably represents a phenyl, pyridyl, thienyl 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 chlorine atom, or a trifluoromethyl, trifluoromethoxy or difluoromethoxy group.
The definition of ring B includes phenyl, 2-, 3- and 4-pyridyl and 2- and 3-thienyl groups, the phenyl, the 3-pyridyl and the 2-thienyl group are preferred, in particular the phenyl group. In a most preferred embodiment B represents a phenyl group, to which one of the substituents R
3
is attached in the 4-position.
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 fluorinated alkyl, fluorinated alkoxy and fluorinated alkylthio groups, especially trifluoromethyl, trifluoromethoxy, difluoromethoxy, difluoromethylthio, trifluoromethylthio, pentafluoroethyl 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, hydroxyl, C
1-4
-alkyl, C
1-4
-alkoxy, C
1-4
-haloalkyl, C
1-4
-haloalkenyl, C
1-4
-haloalkoxy, C
1-4
-haloalkylthio and halosulfanyl groups such as SF
5
. 1 to 5 substituents may suitably be employed, 1 to 2 substituents being preferred.
Typically haloalkyl, haloalkoxy and haloalkylthio groups are trifluoromethyl, trifluoromethoxy, difluoromethoxy, trifluoroethoxy and trifluoromethylthio groups.
m represents an integer from 0 to 5, if ring B represents a phenyl group, and an integer from 0 to 3, if ring B represents a thienyl group. Preferably m is 0, 1, 2 or 3, in particular 1 or 2, most preferred 1.
In formula I A preferably represents a group of formula a, b, c or d:
wherein
R
5
is C
1-3
alkyl and R
4
is C
1-4
alkyl, C
1-3
haloalkyl, a halogen atom, cyano, C
1-3
haloalkoxy or C
1-3
haloalkylthio; while
R
1
is hydrogen, fluorine, chlorine, alkyl, alkoxy or alkylthio, R
2
is hydrogen or halogen, and R
3
is C
1-4
alkyl, chlorine, fluorine, trifluoromethyl, difluoromethoxy or trifluoromethoxy.
Preferred compounds of formula I are those:
wherein A represents a phenyl, pyridyl, thienyl or pyrazolyl group being substituted by one or more of the same or different substituents selected from halogen atoms, alkyl groups, alkoxy groups, haloalkyl groups, haloalkoxy groups, alkylthio groups, haloalkylthio groups and SF
5
groups;
wherein A has a substituent in the meta-position relati

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