KR0131528B1 - Novel pyrimidine derivatives, process for preparation thereof and use thereof as herbicide - Google Patents

Abstract

2,6-di(4,6-dimethoxypyrimidin-2-yl)oxybenzoic acid ester derivative represented by the following general formula(I) is useful as herbicides wherein, R2 and R3, each independently of the other, are the same and different, hydrogen, C1-C4 alkyl, C3-C6 cycloalkyl, aryl, benzyl, C1-C4 alkylcarbonyl, arylcarbonyl, C1-C4 alkoxycarbonyl or benzyloxycarbonyl.

Description

Novel pyrimidine derivatives, their preparation and their use as herbicides

Novel herbicidal pyrimidine derivatives of the present invention, more specifically, novel 2,6-di (4,6-dimethoxypyrimidin-2-yl) oxybenzoic acid ester derivatives represented by the following general formula (I) , And a method for producing the same and its use for combating plants harmful to crops.

Wherein R ₁ and R ₂ are the same as or different from each other, and each independently hydrogen, C ₁ -C ₄ alkyl, C ₃ -C ₆ cycloalkyl, aryl, benzyl, C ₁ -C ₄ alkylcarbonyl, arylcar Carbonyl, C ₁ -C ₄ alkoxycarbonyl or benzyloxycarbonyl. In the above definition, the term alkyl, when used alone or when used in synthetic terms such as alkylcarbonyl, refers to straight or branched chain saturated hydrocarbon radicals such as methyl, ethyl, n-propyl, isopropyl or various butyl isomers and the like; The term alkoxy refers to straight or branched radicals, such as methoxy, ethoxy, n-propoxy, isopropoxy or various butoxy isomers, when used alone or when used in synthetic terms such as alcoholcicarbonyl. It is also well known in the art that 2-phenoxypyrimidine or (pyrimidin-2-yl) oxybenzene derivatives are useful as herbicides. See Agr. Biol. Chem. Vol. 30, P896 (1966), Japanese Patent Laid-Open Nos. 79-55729, United States Patent Nos. 4,248,619 and 4,427,437], and 2- (pyrimidine among compounds developed on the basis of 2-phenoxypyrimidine recently; It has been noted that the -2-yl) oxybenzoic acid derivative exhibits an excellent herbicidal effect. See European Patent Publications 223,406, 249,708, 287,072, 287,079, 315,889 and 321,846. No. 330,990, 335,409, 346,789, 363,040, 402,751, 435,170, 435,186, 457,505, 459,243, 468,690, British Patent Publication No. 2,237,570, Germany Federal Patent Publication No. 3,942,4762]. These known 2- (pyrimidin-2-yl) oxybenzoic acid derivative compounds have a mechanism of action similar to sulfonyl urea derivatives, imidazolinol derivatives and triazolepyrimidine derivatives which are well known as conventional amino acid biosynthesis inhibitory herbicides. As a herbicide with a novel structure of amino acid biosynthesis, which has the apex of easy synthesis, it is focused on this. The herbicidal activity and crop selectivity of these derivatives depend on which substituent is substituted on the benzene ring of 2- (pyrimidin-2-yl) oxybenzoic acid or on the form of the benzoic acid ester derivative. Therefore, the research and development direction of the new herbicides has also been focused on introducing new substituents on the benzene ring or developing ester derivatives of new structures. Extensive research has been conducted to develop ester derivatives of pyrimidin-2-yl) oxybenzoic acid. As a result, it was confirmed that the compound of the general formula (I) according to the present invention as described above shows an excellent herbicidal effect than the existing ester derivative, and completed the present invention.

The present invention relates to a novel 2,6-di (4,6-dimethoxypyrimidin-2-yl) oxybenzoic acid ester derivative represented by the following general formula (I).

Wherein R ₁ and R ₂ are as defined above. Among the novel compounds of the general formula (I) according to the present invention, preferred compounds are those in which R1 and R2 are the same as or different from each other, and are each independently hydrogen, methyl, ethyl, isopropyl, phenyl, benzyl, acetyl, phenylcarbonyl, Methoxycarbonyl, t-butoxycarbonyl or benzyloxycarbonyl. The target compound of the general formula (I) according to the present invention exhibits excellent herbicidal effects on the plant and weeds, broadleaf weeds or other ester derivatives known in the prior art against annual and perennial weeds, It does not express weakness against crops such as rice. In particular, even in extremely low concentrations in the direct growing rice plantation, which has difficulty in controlling weeds, the annual and perennial weeds, including blood, are completely controlled, and the stability of the direct rice in the effective amount of controlling these weeds is also excellent. Representative examples of the compound of general formula (I) according to the present invention are shown in Table 1 below.

Compounds in which the '2,6' position of the benzoic acid is substituted like the compound of the general formula (I) according to the present invention are sterically steeply steric carboxylic acids. Cannot be synthesized by Tetrahedron, Vol, 36, P 2409 (1980); J. Org. Chem., Vol 35, 1198 (1970). Moreover, the esterification of benzoic acid in the case of such steric erosion is generally not useful for the synthesis of the compound according to the present invention since the reaction should generally be carried out under strong acidic conditions. As a result of the study for overcoming this point, the present inventors have effectively prepared the compound of the general formula (I) according to the present invention by using the pyridinethioester compound represented by the following structural formula (II) as an intermediate.

The pyridine thioester compound represented by the above formula (II) is a compound developed by the present applicant and filed in Korean Patent Application No. 93-24099 (Nov. 13, 1993), which is a target compound of the present invention. In addition to the synthesis of the ester compound of I), it is also useful for synthesizing most ester compounds that are difficult to synthesize by a general method. The novel ester derivatives of the general formula (I) according to the present invention can be prepared by reacting the compound of the general formula (II) with a hydroxylamine compound represented by the following general formula (III) in a solvent in the presence of a metal salt.

Wherein R ₁ and R ₂ are as defined above. The method for preparing a compound of formula (I) according to the present invention can be represented by the following scheme A.

Scheme A

R ₁ and R ₂ in the scheme are as defined above. The reaction of Scheme A may be carried out in the presence of an organic solvent which is preferably reaction-inert. Suitable organic solvents for this purpose may be any organic solvent which does not adversely affect the reaction, preferably halogenated hydrocarbons such as dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane or acetonitrile, propio Nitriles such as nitrile and the like. In addition, as the metal salt in the present reaction, a cupric salt such as cupric chloride or cupric bromide may be preferably used, and the reaction may be performed at high temperature or room temperature. The pyridinethio ester compound of formula (II) used as starting material in the reaction of Scheme A is easily synthesized from known benzoic acid compound (IV) (European Patent Publication No. 321,846), as shown in Scheme B below. can do.

Scheme B

As shown in Scheme B, compound (II) can be obtained by reacting compound (IV) with an animal amount of 2,2'-dipyridyldisulfide and triphenylphosphine in a suitable solvent. Preferred solvents for this reaction are hydrocarbon solvents such as benzene, toluene, xylene, acetonitrile, dichloromethane and the like. The invention is illustrated in more detail by the following examples. However, these examples are only provided to aid the understanding of the present invention, and the present invention is not limited in any way by these examples.

[Production Example 1]

Synthesis of 2,6-di (4,6-dimethoxypyrimidin-2-yl) oxybenzoic acid 2-pyridinethio ester (II)

48.0 g of known compounds 2,6-di (4,6-dimethoxypyrimidin-2-yl) oxybenzoic acid (European Patent Publication No. 321,846), 22.0 g of 2,2'dipyridyldisulfide and triphenylphosph 26.2 g of pin was added to 250 ml of toluene and stirred vigorously at room temperature for 3 hours. After filtering the reaction mixture, the filtrate was distilled off under reduced pressure to remove toluene. The residue was subjected to column chromatography on silica gel (hexane: ethyl acetate = 2: 1) to give 42.0 g (yield: 90%) of the title compound (II) as a white solid.

¹ H NMR (CDCl ₃ , δ): 3.77 (s, 6H), 6.03 (s, 2H), 7.32-7.87 (m, 6H), 8.54-8.55 (d, 1H)

Example 1

Synthesis of Compound (3)

0.9 g of known compounds N, N-diethylhydroxylamine and 4.0 g of pyridinethio ester compound (II) synthesized in Preparation Example 1 were dissolved in 50 ml of dichloromethane and stirred at room temperature. After 5 minutes, 2.2 g of cupric bromide was added and further stirred for 1 hour. The reaction mixture was filtered to concentrate the filtrate, and column chromatography on silica gel (hexane: ethyl acetate = 2: 1) afforded 2.9 g (yield: 85%) of the title compound (3). By reacting the compound (II) prepared in Preparation Example 1 with the corresponding hydroxylamine in substantially the same manner as in Example 1, the target compounds of the general formula (I) described in Table 1 may be synthesized. The physical properties of the synthesized compounds are shown in Table 2 below.

The ester derivatives of the general formula (I) according to the present invention show excellent herbicidal activity against weeds without harm to crops, and thus can be used as effective herbicides in rice and wheat cultivation, especially in cultivated rice plants. When the compound according to the present invention is used as a herbicide, the active compound may be used as it is or with solid substances such as clay, talc, diatomaceous earth or liquid substances such as water, alcohol, benzene, toluene, ether, ketones, esters, acids and amides. It can be mixed and formulated into a conventional formulation in agriculture, such as liquids, emulsions, powders, granules, and the like. Such formulations are additionally added with emulsifiers, dispersants, penetrants, electrodeposition agents, stabilizers as needed. Some examples of the formulation of the herbicide containing the compound according to the present invention as an active ingredient are shown below, but the present invention is not limited in any way.

Formulation Example 1

(Field conditions, 500g / ㏊)

The desired compound was prepared by dissolving 160 mg of the compound according to the present invention in 640 ml of a soluble solvent (acetone) and diluting with 640 ml of distilled water containing 0.2% of a nonionic surfactant, Tween 20.

Formulation Example 2

(Field conditions, 250 g / ㏊)

The desired compound was prepared by dissolving 80 mg of the compound according to the present invention in 320 ml of a soluble solvent (acetone) and distilled with 320 ml of distilled water containing 0.2% of a nonionic surfactant, Tween 20.

In order to test the herbicidal efficacy of the novel herbicidal 2,6-di (4,6-dimethoxypyrimidin-2-yl) oxybenzoic acid ester derivative of the general formula (I) according to the present invention, Pot cultivation and treatment with the active compound of the present invention, the degree of damage of the treated plants was judged by moonshine evaluation to determine the efficacy according to the efficacy and weakness evaluation criteria shown in Table 3 below.

Field weeds for assaying the herbicidal efficacy of the compounds according to the present invention include Digitaria sanguinalis, Alopecurus aequallis, Setaria farberi, Echinochloa crus-galli var.caudata, Amaranthus retroflexus ), Aeschynomene indica, Solanum nigrum, Abutilon theophrasti, Xanthium strumarium, and Panicum dichotomiflorum, and Echinochloa crus-galli var. Oryzicola ), Eleocharis kuroguwai, Sagittaria trifolia, Olmi (Sagittaria pygmaea), etc. were selected, and wheat (Triticum aestivum) and rice (Oryza sativar) were selected as crops.

Experimental Example 1

[Test of herbicidal power before germination by soil treatment (field conditions)]

After filling the sterilized field soil (sand soil, pH 5.5-6.0) into a rectangular plastic container (20X15X10cm), six kinds of field weeds were sown in one container with a surface area of 300cm2, and the soil was 0.5cm. After 1 day of irrigation, the solution of Formulation Example 1 was uniformly sprayed onto the soil surface to apply the active ingredient corresponding to the treatment amount (500 g / ㏊). The plants were cultivated and observed for 30 days after the treatment, and the herbicidal power against weeds was assessed according to the evaluation criteria of Table 3 above, and the results are shown in Table 4 below.

Experimental Example 2

[Measurement of herbicidal power after germination by foliage treatment (field conditions)]

After seeding the assay plants in the same manner as in Experimental Example 1 and cultivating for 10 to 14 days, when the plants reach the 3 to 4 leaf stage, the solution of 1 is applied to the formulation to apply the active ingredient corresponding to the treatment amount (500 g / ㏊) Sprayed evenly on the foliage area of. After 30 days of treatment, the plants were grown and the condition of the plants was observed, and the herbicidal ability of the weeds was assessed according to the evaluation criteria, and the results are shown in Table 5 below.

Experimental Example 3

[Herbicidal Effect and Crop Harm Test in Germination]

The treatment dose was 250 g / dL or 125 g / dL, and the herbicidal power against weeds and the damage to wheat were tested in substantially the same manner as in Experimental Example 1, and the results are shown in Table 6 below.

Experimental Example 4

Experiments on Herbicidal Effect and Crop Studies in Post- Germination Treatments

The treatment dose was set at 63 g / dL or 32 g / dL, and the herbicidal force against weeds and the damage to wheat were tested in substantially the same manner as in Experimental Example 2, and the results are shown in Table 7 below.

[Experiment 5]

[Test of herbicidal efficacy before germination by soil treatment (field conditions)]

Sterilized paddy soil (plant soil, pH 5.5-6.0) was filled in a square pot (30 × 15 × 10 cm), and the weeds were sown in the state having a surface area of 450 cm 2 and incorporated into soil soil. After 1 day of irrigation at a depth of 4 cm, the solution of Formulation Example 2 was instilled in a pot so that an active ingredient corresponding to the amount of the treatment was applied. Plants were grown and observed for 4 weeks after treatment, and the herbicidal effects on weeds were assessed according to the criteria of Table 3 above, and the results are shown in Table 8 below.

Experimental Example 6

Experiments on Herbicidal Effect and Crop Harm after Germination by Foliar Leaves

Sterilized paddy soil (plant soil, pH 5.5-6.0) was filled in a square pot (30X15X10cm), and rice and paddyweed were sown in the state of the surface area of 450 cm <2>, and it was made up to 0.5cm. After cultivating at a temperature of 20 to 25 ° C. for 12 to 14 days, when plants reached 2-3 leaves, the solution of Formulation Example 1 was uniformly sprayed on the foliage of plants so that an active ingredient corresponding to the treatment amount was applied. Plants were cultivated and observed for 30 days after treatment, and the herbicidal power against the weeds and the damage to crops were assessed according to the evaluation criteria of Table 3 above, and the results are shown in Table 9 below.

Claims (7)

Novel 2,6-di (4,6-dimethoxypyrimidin-2-yl) oxybenzoic acid ester derivatives of the general formula (I) Wherein R ₁ and R ₂ are the same as or different from each other, and each independently hydrogen, C ₁ -C ₄ alkyl, C ₃ -C ₆ cycloalkyl, C ₁ -C ₄ alkylcarbonyl, C ₁ -C ₄ alkoxy Carbonyl or benzyloxycarbonyl. The compound of claim 1, wherein R ₁ and R ₂ are the same as or different from each other, and each independently hydrogen, methyl, ethyl, isopropyl, phenyl, benzyl, acetyl, phenylcarbonyl, methoxycarbonyl, t-butoxycarbon A compound of formula (I) representing carbonyl or benzyloxycarbonyl. A process for preparing a compound of formula (I), wherein the compound of formula (II) is reacted in addition to the hydroxylamine derivative of formula (III) in a solvent in the presence of a metal salt: Wherein R ₁ and R ₂ are the same as or different from each other, and are each independently hydrogen, C ₁ -C ₄ alkyl, C ₃ -C ₆ cycloalkyl, aryl, benzyl, C ₁ -C | ₄ alkylcarbonyl, C ₁ -C ₄ alkoxycarbonyl or benzyloxycarbonyl. 4. The method of claim 3 wherein the metal salt is a cupric salt selected from cupric chloride and cupric bromide. 4. A process according to claim 3, wherein the solvent is selected from the group consisting of dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, acetonitrile and propionitrile. A herbicide composition for controlling weeds in rice or wheat cultivation, comprising as an active ingredient at least one compound of formula (I) according to claim 1. 7. The herbicide composition according to claim 6, for controlling weeds in direct growing rice fields.