Herbicidally active pyridine sulfonyl urea derivatives

Details Herbicidally active pyridine sulfonyl urea derivatives Herbicidally active pyridine sulfonyl urea derivatives

2003-12-05

2004-07-13

Rao, Debrak (Department: 1624)

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

Reexamination Certificate

active

06762305

ABSTRACT:

TECHNICAL FIELD
The present invention relates to pyridine sulfonyl urea derivatives represented by the following formula (1):
in which
n denotes an integer of from 1 to 3,
R represents H or C
1
-C
4
-alkyl,
R′ represents H, C
1
-C
4
-alkyl, C
1
-C
3
-haloalkyl, halogen, or C
1
-C
2
-alkoxy, and
X and Y independently of one another represent C
1
-C
2
-alkyl, C
1
-C
2
-alkoxy, C
1
-C
2
-haloalkoxy, or halogen, salts or stereochemical isomers thereof showing an effective herbicidal activity in pre- and/or post-emergence treatment in rice farming, or to a method to use thereof, a method for the preparation thereof, an intermediate used for the preparation thereof, and a herbicidal composition comprising same.
BACKGROUND ART
Hitherto, there have been reported a lot of sulfonyl urea derivatives having a herbicidal activity in rice farming. For example, JP 61/191602 discloses a compound represented by the following formula (2):
which has been commercialized as a herbicide for rice farming in the name of Pyrazosulfuron-ethyl.
Korean Patent No. 70675 discloses a compound represented by the following formula (3):
in which
R represents haloalkyl,
X and Y independently of one another represent CH
3
, OCH
3
, Cl, etc., and
Z represents CH or N.
Korean Patent Application No. 91-3014 discloses a herbicidally active sulfonyl urea derivative represented by the following formula (4):
in which
R, X, Y and Z are defined as the above formula (3),
R′ represents H or CH
3
, and
P and Q independently of one another represent CH or N, but where the aromatic ring including P and Q is benzene or pyridine.
Korean Patent Application No. 93-6915 discloses a herbicidally active pyridine sulfonyl urea derivative represented by the following formula (5):
in which
P, Q, R′, X and Y are defined as in the above formula (4),
R represents H, R
a
—(C═O)— or R
a
—X
a
—(C═O)—, wherein R
a
represents C
1
~C
4
-alkyl, C
1
~C
3
-haloalkyl, C
2
~C
4
-alkenyl or C
2
~C
4
-alkynyl, and X
a
represents O, S, NH or NR
a
.
The existing sulfonyl urea-based herbicidal compounds as explained above show an excellent herbicidal activity against annual and perennial weeds in rice, but have weak activity to barnyardgrass which is the most problematic weed in rice, or cause some phytotoxicity to rice plant. The present inventors claim new pyridine sulfonyl urea derivatives having improved rice safety and superior herbicidal activity against barnyardgrass to the earlier herbicidal compounds, and find great advantages of these new compounds when used as a rice herbicide.
Therefore, one object of the present invention is to provide the pyridine sulfonyl urea derivatives of the above formula (1), salts or stereochemical isomers thereof.
It is another object of the present invention to provide a process for the preparation of the compound of formula (1).
It is further object of the present invention to provide a novel intermediate which is used for the preparation of the compound of formula (1).
It is further object of the present invention to provide a method to use the compound of formula (1) as a herbicide for paddy rice, and a herbicidal composition comprising same.
The present invention will be explained in more detail hereinafter.
DISCLOSURE OF INVENTION
The present invention relates to a compound of the following formula (1):
in which
n denotes an integer of from 1 to 3,
R represents H or C
1
-C
4
-alkyl,
R′ represents H, C
1
-C
4
-alkyl, C
1
-C
3
-haloalkyl, halogen, or C
1
-C
2
-alkoxy, and
X and Y independently of one another represent C
1
-C
2
-alkyl, C
1
-C
2
-alkoxy, C
1
-C
2
-haloalkoxy, or halogen.
Among the compound of formula (1) which shows an excellent selectivity to rice plant and herbicidal activity to barnyardgrass and thus, can be advantageously used as a herbicide for rice farming, the preferred compounds include those wherein n denotes an integer of 1 or 2, R represents H or methyl, R′ represents H, halogen or methyl, and X and Y each represents methoxy.
Particularly preferred compounds include those wherein n denotes an integer of 1 or 2, R represents methyl, R′ represents H, Cl, Br or methyl, and X and Y each represents methoxy.
Typical examples of the compound of formula (1) according to the present invention are exemplified as follows:
N-[(4,6-dimethoxypyrimidin-2-yl)aminocarbonyl]-2-(2-fluoro-1-methoxy acetoxy-n-propyl)pyridine-3-sulfonamide.
N-[(4,6-dimethoxypyrimidin-2-yl)aminocarbonyl]-2-(2-fluoro-1-hydroxy acetoxy-n-propyl)pyridine-3-sulfonamide.
N-[(4,6-dimethoxypyrimidin-2-yl)aminocarbonyl]-2-(2-fluoro-1-(3-hydroxy propion)oxy-n-propyl)pyridine-3-sulfonamide.
N-[(4,6-dimethoxypyrimidin-2-yl)aminocarbonyl]-2-(2-fluoro-1-(3-methoxypropion)oxy-n-propyl)pyridine-3-sulfonamide.
N-[(4,6-dimethoxypyrimidin-2-yl)aminocarbonyl]-4-methyl-2-(2-fluoro-1-methoxyacetoxy-n-propyl)pyridine-3-sulfonamide.
N-[(4,6-dimethoxypyrimidin-2-yl)aminocarbonyl]-4-chloro-2-(2-fluoro-1-methoxyacetoxy-n-propyl)pyridine-3-sulfonamide.
N-[(4,6-dimethoxypyrimidin-2-yl)aminocarbonyl]-4-bromo-2-(2-fluoro-1-methoxyacetoxy-n-propyl)pyridine-3-sulfonamide.
Since the compound of formula (1) has two asymmetric carbons therein, they can exist as an erythro or threo isomer, or mixtures thereof. The compound of the present invention shows a stronger activity in the erythro form, but the mixtures thereof in a suitable mixing ratio also exhibit a sufficient activity.
The compound of formula (1) according to the present invention can be prepared by a process characterized in that a compound represented by the following formula (6):
in which
n, R and R′ are defined as in the above formula (1), is reacted in a solvent optionally in the presence of a base with a compound represented by the following formula (7):
 in which
X and Y are defined as in the above formula (1). Therefore, it is another object of the present invention to provide such a preparation process.
The compound of formula (6) used as a starting material in the process according to the present invention can exist as an erythro isomer, threo isomer, or mixtures thereof. The stereo-chemical configuration of the desired compound of formula (1) may be determined in line with the configuration of compound (6).
Any solvent which does not adversely affect the reaction can be used in the above process, but preferably tetrahydrofuran, acetone, acetonitrile, dioxane, methylene chloride, toluene, butanol, pyridine, dimethylformamide, etc. can be used. The above process is carried out preferably in the presence of a small amount of strong base, such as for example, triethylamine, hexamethylenetetramine, pyridine, DBU or DABCO (wherein DBU means 1,8-diazabicyclo[5,4,0]undec-7-ene and DABCO means 1,4-diazabicyclo[2,2,2]octane, and they have the same meaning throughout the present specification), etc., and the reaction temperature may be preferably maintained in the range of 10~80° C. The specific reaction conditions can be referred to U.S. Pat. No. 4,443,245 which discusses similar reactions, and after the reaction is completed, the desired compound can be obtained through the acid-treatment procedure as described in EP 044,807. If a highly pure compound is required, it is desirable to use HPLC technique.
The compound of formula (7) was known and can be easily prepared according to the process described in Korean Patent No. 70,675.
The compound of formula (6) is a novel intermediate which is provided first by the present invention. Therefore, it is another subject matter to be provided by the present invention. The compound of formula (6) can be prepared by treating a compound represented by the following formula (8):
in which, n, R and R′ are defined as formula (1), with trifluoroacetic acid (TFA) to eliminate the t-butyl group therefrom.
If the compound of formula (8) is stirred in the solvent of trifluoroacetic acid(TFA) at 0~80° C., the t-butyl group is eliminated to give the sulfonamide compound of formula (6). When the compound of fo

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