4-aminopicolinates and their use as herbicides

Details 4-aminopicolinates and their use as herbicides 4-aminopicolinates and their use as herbicides

2001-01-12

2001-10-02

Davis, Zinna Northington (Department: 1625)

Plant protecting and regulating compositions

Plant growth regulating compositions

Organic active compound containing

C504S244000, C504S255000, C546S296000, C546S297000, C546S306000, C546S311000, C546S312000

Reexamination Certificate

active

06297197

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to certain novel 4-aminopicolinates and their derivatives and to the use of these compounds as herbicides.
A number of picolinic acids and their pesticidal properties have been described in the art. For example, U.S. Pat. No. 3,285,925 discloses 4-amino-3,5,6-trichloropicolinic acid derivatives and their use as plant growth control agents and herbicides. U.S. Pat. No. 3,325,272 discloses 4-amino-3,5-dichloropicolinic acid derivatives and their use for the control of plant growth. U.S. Pat. No. 3,317,549 discloses 3,6-dichloropicolinic acid derivatives and their use as plant growth control agents. U.S. Patent 3,334,108 discloses chlorinated dithiopicolinic acid derivatives and their use as parasiticides. U.S. Pat. No. 3,234,229 discloses 4-amino-polychloro-2-trichloromethylpyridines and their use as herbicides. In
Applied and Environmental Microbiology
, Vol. 59, No. 7, July 1993, pp. 2251-2256, 4-amino-3,6-dichloropicolinic acid is identified as a product of the anaerobic degradation of 4-amino-3,5,6-trichloropicolinic acid, the commercially available herbicide picloram.
While picloram is recommended for the control of woody plants and broadleaf weeds in certain applications, its properties are not ideal. It would be highly desirable to discover related compounds that are more potent, more selective or of broader spectrum in their herbicidal activity and/or that have improved toxicological or environmental properties.
SUMMARY OF THE INVENTION
It has now been found that certain 4-aminopicolinic acids and their derivatives having selected substituents in the 3-, 5-, and 6-positions are potent herbicides with a broad spectrum of weed control and excellent crop selectivity. The compounds further possess excellent toxicological or environmental profiles.
The invention includes compounds of Formula I:
wherein
X represents H, halogen, C
1
-C
6
alkoxy, C
1
-C
6
alkylthio, aryloxy, nitro or trifluoromethyl;
Y represents halogen, C
1
-C
6
alkoxy, C
1
-C
6
alkylthio, aryloxy, heteroaryloxy or trifluoromethyl;
Z represents halogen, C
1
-C
6
alkoxy, C
1
-C
6
alkylthio, aryloxy or nitro; and
W represents —NO
2
, —N
3
, —NR
1
R
2
, —N═CR
3
R
4
or —NHN═CR
3
R
4
where
R
1
and R
2
independently represent H, C
1
-C
6
alkyl, C
3
-C
6
alkenyl, C
3
-C
6
alkynyl, aryl, heteroaryl, hydroxy, C
1
-C
6
alkoxy, amino, C
1
-C
6
acyl, C
1
-C
6
carboalkoxy, C
1
-C
6
alkylcarbamyl, C
1
-C
6
alkylsulfonyl, C
1
-C
6
trialkylsilyl or C
1
-C
6
dialkyl phosphonyl or R
1
and R
2
taken together with N represent a 5- or 6-membered saturated or unsaturated ring which may contain additional O, S or N heteroatoms; and
R
3
and R
4
independently represent H, C
1
-C
6
alkyl, C
3
-C
6
alkenyl, C
3
-C
6
alkynyl, aryl or heteroaryl or R
3
and R
4
taken together with ═C represent a 5- or 6-membered saturated ring; and
agriculturally acceptable derivatives of the carboxylic acid, with the proviso that when X represents H or Cl, then Y and Z are not both Cl.
Compounds of Formula I wherein X represents H or F, wherein Y represents F, Cl, Br or aryloxy, wherein Z represents Cl and wherein R
1
and R
2
represent H are independently preferred.
The invention includes herbicidal compositions comprising a herbicidally effective amount of a 4-amino-picolinate of Formula I:
wherein
X represents H, halogen, C
1
-C
6
alkoxy, C
1
-C
6
alkylthio, aryloxy, nitro or trifluoromethyl;
Y represents halogen, C
1
-C
6
alkoxy, C
1
-C
6
alkylthio, aryloxy, heteroaryloxy or trifluoromethyl;
Z represents halogen, C
1
-C
6
alkoxy, C
1
-C
6
alkylthio, aryloxy or nitro; and
W represents —NO
2
, —N
3
, —NR
1
R
2
, —N═CR
3
R
4
or —NHN═CR
3
R
4
where
R
1
and R
2
independently represent H, C
1
-C
6
alkyl, C
3
-C
6
alkenyl, C
3
-C
6
alkynyl, aryl, heteroaryl, hydroxy, C
1
-C
6
alkoxy, amino, C
1
-C
6
acyl, C
1
-C
6
carboalkoxy, C
1
-C
6
alkylcarbamyl, C
1
-C
6
alkylsulfonyl, C
1
-C
6
trialkylsilyl or C
l
-C
6
dialkyl phosphonyl or R
1
and R
2
taken together with N represent a 5- or 6-membered saturated or unsaturated ring which may contain additional O, S or N heteroatoms; and
R
3
and R
4
independently represent H, C
1
-C
6
alkyl, C
3
-C
6
alkenyl, C
3
-C
6
alkynyl, aryl or heteroaryl or R
3
and R
4
taken together with =C represent a 5- or 6-membered saturated ring; and
agriculturally acceptable derivatives of the carboxylic acid, with the proviso that when X represents Cl, then Y and Z are not both Cl in admixture with an agriculturally acceptable adjuvant or carrier. The invention also includes a method of use of the compounds and compositions of the present invention to kill or control undesirable vegetation by application of an herbicidal amount of the compound to the vegetation or to the locus of the vegetation as well as to the soil prior to emergence of the vegetation. The use of the compounds to kill or control woody plants and broadleaf weeds in grass crops is a preferred utility and post-emergent application of the compounds to the undesirable vegetation is a preferred method of application.
DETAILED DESCRIPTION OF THE INVENTION
The herbicidal compounds of the present invention are derivatives of 4-aminopicolinic acids:
These compounds are characterized by possessing halogen, C
1
-C
6
alkoxy, C
1
-C
6
alkylthio, aryloxy or nitro substituents in the 3-position with halogen being preferred and chlorine being most preferred; by possessing hydrogen, halogen, C
1
-C
6
alkoxy, C
1
-C
6
alkylthio, aryloxy, nitro or trifluoromethyl substituents in the 5-position with hydrogen and fluorine being preferred; and by possessing halogen, C
1
-C
6
alkoxy, C
1
-C
6
alkylthio, aryloxy, heteroaryloxy or trifluoromethyl substituents in the 6-position with fluorine, chlorine, bromine or aryloxy being preferred. Preferred aryloxy groups in the 6-position are 3-substituted phenoxy groups, most preferably phenoxy groups substituted with halogen or C
1
-C
4
alkyl groups in the 3-position.
The amino group at the 4-position can be unsubstituted or substituted with one or more C
1
-C
6
alkyl, C
3
-C
6
alkenyl, C
3
-C
6
alkynyl, aryl, heteroaryl, hydroxy, C
1
-C
6
alkoxy or amino substituents. The amino group can be further derivatized as an amide, a carbamate, a urea, a sulfonamide, a silylamine, a phosphoramidate, an imine or a hydrazone. Such derivatives are capable of breaking down into the amine. An unsubstituted amino group or one substituted with one or more alkyl substituents is preferred.
The carboxylic acids of Formula I are believed to be the compounds that actually kill or control undesirable vegetation and are typically preferred. Analogs of these compounds in which the acid or amine group of the picolinic acid is derivatized to form a related substituent that can be transformed within plants or the environment to a acid group possess essentially the same herbicidal effect and are within the scope of the invention. Therefore, an “agriculturally acceptable derivative”, when used to describe the carboxylic acid functionality at the 2-position, is defined as any salt, ester, acylhydrazide, imidate, thioimidate, amidine, amide, orthoester, acylcyanide, acyl halide, thioester, thioester, dithiolester, nitrile or any other acid derivative well known in the art which (a) does not substantially affect the herbicidal activity of the active ingredient, i.e., the 4-aminopicolinic acid, and (b) is or can be hydrolyzed in plants or soil to the picolinic acid of Formula I that, depending upon the pH, is in the dissociated or the undissociated form. Likewise, an “agriculturally acceptable derivative”, when used to describe the amine functionality at the 4-position, is defined as any salt, silylamine, phosphorylamine, phosphinimine, phosphoramidate, sulfonamide, sulfinimine, sulfoximine, aminal, hemiaminal, amide, thioamide, carbamate, thiocarbamate, amidine, urea, imine, nitro, nitroso, azide, or any other nitrogen containing derivative well known in the art which (a) does not substantially affect the herbicidal activity of

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