JPH0143732B2 - - Google Patents

Description

[Detailed description of the invention]

This invention is based on the general formula (However, in the formula, X represents a lower alkyl group or a chlorine atom, n represents 0, 1, 2, or 3, and R ₁
represents a lower alkyl group having 2 or 3 carbon atoms,
R ₂ represents a hydrogen atom, a lower alkyl group, a lower alkenyl group, or a methoxy group, R ₃ represents a hydrogen atom or a lower alkyl group, Y represents a lower alkyl group, a chlorine atom, or a lower alkoxy group, m
indicates 0, 1 or 2. ) A novel benzylamide derivative of phenoxyalkanoic acid,
The present invention also provides a herbicide containing this new benzylamide derivative of phenoxyalkanoic acid as an active ingredient. Many herbicides containing phenoxy compounds as active ingredients have been proposed for a long time, and few are commercially available. Examples include 2,4-D [active ingredient 2,4-dichlorophenoxyacetic acid], 2 ,4
-DP [active ingredient 2-(2,4-dichlorophenoxy)propionic acid] MCP [active ingredient 2-methyl-
4-chlorophenoxyacetic acid] or MCPCA
Examples include herbicides such as [active ingredient N-(2-chlorophenyl)-2-methyl-4-chlorophenoxyacetamide]. These conventionally known phenoxy herbicides generally have extremely superior herbicidal effects against a wide range of broad-leaved weeds compared to other herbicides, but they suppress tillering due to auxin action on grass crops. They have a common characteristic of being associated with drug damage such as malformations. The inventors aimed to find a compound among phenoxy compounds that has excellent herbicidal activity and is not harmful to crops, and synthesized various compounds of this family and searched for their plant activities. . As a result, we succeeded in synthesizing a benzylamide derivative of phenoxyalkanoic acid, which is a new compound represented by the above-mentioned general formula (1) and which has not been reported in the literature. The present invention was completed based on the discovery that the present invention has the ability to selectively eliminate a wide range of weeds that occur in cultivated land without causing any chemical damage to crops. In other words, the herbicide of the present invention not only has an excellent herbicidal effect on broad-leaved weeds but also other weeds through its bleaching action, and is effective against grasses and other crops compared to conventionally known phenoxy herbicides. There is almost no drug damage due to the auxin effect, and there is no toxicity to humans, livestock, fish or shellfish, and there is no off-odor. The benzylamide derivative of phenoxyalkanoic acid in this invention is, for example, the following (1) or
It can be synthesized by reaction (2). (However, X, Y, R ₁ , R ₂ , R ₃ and n in the formula,
m has the same meaning as above. Z means a chlorine atom or a bromine atom. ) The above reactions (1) and (2) are carried out in the presence of a suitable solvent,
This is preferably carried out by adding a weak alkali such as pyridine, triethylamine, sodium carbonate or potassium carbonate. Examples of the solvent used in the reaction include aromatic hydrocarbons such as benzene, toluene, and xylene, ethers such as diethyl ether, tetrahydrofuran, and dioxane, and ketones such as methyl ethyl ketone and dimethyl ketone. In particular, ethers or ketones are preferably used in reaction (2). The reaction temperature varies depending on the type of reagent and solvent used and is not particularly limited, but it is 0°C to 30°C for reaction (1) and 50°C for reaction (2).
Preferably carried out at ~130°C. Reaction time is approximately 1 to 10 hours. Next, specific synthesis examples of the present invention will be given. Next, an example of its synthesis will be shown. Synthesis Example 1 Synthesis of N-benzyl-2-(3,5-dimethylphenoxy)-butyramide (compound No. 30 in Table 1 below) 1.8 g (0.017 mol) of benzylamine and pyridine
Dissolve 1.2g (0.015mol) in 30ml of benzene,
3.0 g (0.013 mol) of 2-(3,5-dimethylphenoxy)-butyroyl chloride under stirring at room temperature.
Appropriately. After reacting for 5 hours, the reaction solution was washed with water, diluted hydrochloric acid, diluted caustic soda, and water in this order, the benzene layer was dehydrated, and then the benzene was distilled off. The obtained crude crystals were recrystallized from n-hexane, and the melting point was 93-94℃.
Colorless acicular N-benzyl-2-(3,5-
2.4 g of dimethylphenoxy)-butyramide was obtained. Synthesis example 2 N-(2-methylbenzyl)-2-(3,5-
Synthesis of dichlorophenoxy)-butyramide (compound number 116 in Table 1 below) 2-methylbenzylamine 1.5 g (0.012 mol)
and triethylamine (1.0 g (0.01 mol)) were dissolved in 30 ml of benzene, and 2-(3,5
-dichlorophenoxy)-butyroyl chloride
A solution of 2.8 g (0.01 mol) in 20 ml of benzene was added dropwise. After reacting for 2 hours, the reaction solution was washed with dilute hydrochloric acid, diluted caustic soda, and water in this order, and the benzene layer was dehydrated, and then the benzene was distilled off. The obtained crude crystals were recrystallized with ethanol, and the melting point was
2.3 g of colorless prismatic N-2-methylbenzyl)-2-(3,5-dichlorophenoxy)-butyramide was obtained, exhibiting a temperature of 135 to 137°C. Synthesis Example 3 Synthesis of N-benzyl-2-(4-chloro-3-methylphenoxy)-valeramide (see Part 1 below)
Compound No. 54 in the table) 3.5 g of N-benzyl-α-bromvaleramide
(0.013 mol) and 6.3 g (0.040 mol) of 4-chloro-3-methylphenol were dissolved in 60 ml of acetone, and 6.9 g (0.050 mol) of anhydrous potassium carbonate was dissolved in this.
was added, and the mixture was boiled and refluxed while stirring for 10 hours. After cooling, distill off the acetone and add 100ml of water to the residue.
was added, and the precipitated oil was extracted with benzene. The benzene layer was washed with dilute hydrochloric acid, dilute caustic soda, and water in this order, dehydrated, and then benzene was distilled off. The residue was applied to a silica gel column to obtain 3.0 g of N-benzyl-2-(4-chloro-3-methylphenoxy)-valeramide as a colorless oil. When left at room temperature, it crystallized and had a melting point of 75-78°C. Table 1 lists examples of the novel benzylamide derivatives of phenoxyalkanoic acid according to the present invention, which were produced according to the above synthesis examples. In addition, the upper row of elemental analysis values in Table 1 shows theoretical values, and the lower row shows actual measured values.

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[Table] In this invention, when the benzylamide derivative of phenoxyalkanoic acid is used as a herbicide, an inert solid carrier,
Using liquid carriers and emulsifying dispersants, granules,
It can be used in any dosage form such as powder, emulsion, wettable powder, tablet, aerosol, and smoke.
Examples of these inert carriers include talc,
Clay, kaolin, diatomaceous earth, calcium carbonate, potassium chlorate, saltpeter, wood flour, nitrocellulose, starch, benzene, xylene, n-hexane, gum arabic, vinyl chloride, carbon dioxide gas,
Freon, propane, butane, etc. may be mentioned. Further, auxiliary agents for formulation, such as spreading agents, diluents, surfactants, solvents, etc., may be appropriately added. Furthermore, it can be used by appropriately mixing with fungicides, insecticides, other agricultural chemicals, urea, ammonium sulfate, ammonium phosphorous, potassium salts and other fertilizer substances, soil improvers, and the like. Next, examples of the herbicide of this invention will be given. Note that parts in each example indicate parts by weight. Example 1 N-benzyl-2-(3,5-dimethylphenoxy)-butyramide (compound No. 30)
50 parts of xylene, and 10 parts of Solpol 800 (surfactant, trade name) were mixed and dissolved to obtain an emulsion. Example 2 N-(2-methylbenzyl)-2-(3,5-
A wettable powder was obtained by mixing and pulverizing 50 parts of dichlorophenoxy)-butylamide (compound No. 116), 30 parts of kaolin, 15 parts of bentonite, and 5 parts of sodium ligninsulfonate. Example 3 N-benzyl-2-(3-chlorophenoxy)
-7 parts of butyramide (compound number 67),
After mixing and pulverizing 60 parts of bentonite, 30 parts of talc, and 3 parts of sodium naphthalene sulfonate, an appropriate amount of water was added and kneaded, followed by granulation using a granulator to obtain granules. Next, the effects of the herbicide of the present invention will be specifically explained using experimental examples. In addition, the test compound number in each experimental example is the same as the compound number in Table 1. Experimental example 1 Soil treatment test Paddy soil (diluvial soil) in a 1/9000 are pot
The seeds of various weeds such as wild grass, broad-leaved weeds (kikashigusa, azalea, and cypress), bulrushes, and cypress were uniformly mixed and sown on the surface layer.
Urikawa tubers and paddy rice seedlings at the three-leaf stage were transplanted, and water was added to make them submerged to a depth of 3 cm. then 3
A day later, at the beginning of the emergence of various weeds, a predetermined amount of the diluted solution of each wettable powder produced according to Example 2 was uniformly sprayed on the flooded surface. Four weeks after spraying, the herbicidal effects of each test compound were investigated. The results are shown in Table 2. 5: Completely dried grass 4: Severe damage 3: Medium damage 2: Minor damage 1: Slight damage 0: No harm (normal growth) In addition, the upper row of each column in Table 2 shows the amount of active ingredient 50g/are, and the lower row shows 25g. / Shows the results of an experiment conducted with R.

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[Table] Experimental example 2 Upland soil treatment test A 1/5000 are pot was filled with upland soil (diluvial soil), and seeds of corn, soybean, millet, crabgrass, clover, purslane, and white grass were sown, and after covering with soil, A predetermined amount of each diluted wettable powder produced according to Example 2 was uniformly sprayed using a pressure sprayer. Three weeks after the chemical treatment, the herbicidal effects of each test compound were investigated. The result is the third
Shown in the table. The criteria for the herbicidal effect in Table 3 are the same as in Experimental Example 1. Note that the upper row of each column in Table 3 shows the results of experiments conducted using an active ingredient amount of 50 g/are, and the lower row shows the results of experiments conducted with an amount of 25 g/are.

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[Table] From the above experimental results, it was found that the herbicide of this invention is highly safe for crops and has excellent herbicidal effects against various weeds. It is recognized that it is a drug.

Claims (1)

[Claims] 1. General formula (However, in the formula, X represents a lower alkyl group or a chlorine atom, n represents 0, 1, 2, or 3, and R ₁
represents a lower alkyl group having 2 or 3 carbon atoms,
R ₂ represents a hydrogen atom, a lower alkyl group, a lower alkenyl group, or a methoxy group, R ₃ represents a hydrogen atom or a lower alkyl group, Y represents a lower alkyl group, a chlorine atom, or a lower alkoxy group, m
indicates 0, 1 or 2. ), a benzylamide derivative of phenoxyalkanoic acid. 2 General formula (However, in the formula, X represents a lower alkyl group or a chlorine atom, n represents 0, 1, 2, or 3, and R ₁
represents a lower alkyl group having 2 or 3 carbon atoms,
R ₂ represents a hydrogen atom, a lower alkyl group, a lower alkenyl group, or a methoxy group, R ₃ represents a hydrogen atom or a lower alkyl group, Y represents a lower alkyl group, a chlorine atom, or a lower alkoxy group, m
indicates 0, 1 or 2. ) A herbicide characterized by containing a benzylamide derivative of phenoxyalkanoic acid as an active ingredient.