JPH0142256B2 - - 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, a halogen atom or a nitro group, n represents 0, 1, 2 or 3, R represents a lower alkyl group having 2 or 3 carbon atoms, Y represents a furyl group, This invention provides a novel amide derivative of phenoxyalkanoic acid represented by a thienyl group, a pyridyl group, or a naphthyl group, and a herbicide containing this new amide derivative of phenoxyalkanoic acid as an active ingredient. be. Many herbicides containing phenoxy compounds as active ingredients have been proposed for a long time, and many 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 phenoxyalkanoic acid amide derivative, which is a new compound represented by the above-mentioned general formula [] and which has not been described in the literature, and this derivative occurs in rice fields, fields, other cultivated land, and non-cultivated land. This invention was completed based on the discovery that the present invention has the ability to selectively eliminate a wide range of weeds 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 conventional 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 amide derivative of phenoxyalkanoic acid in this invention can be synthesized, for example, by the following reaction. (However, X, Y, R and n in the formula have the same meanings as above. Z means a chlorine atom or a bromine atom.) The above reaction is carried out in the presence of an appropriate solvent, using pyridine,
This is preferably carried out by adding a weak alkali such as 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. The reaction temperature varies depending on the type of reagent and solvent used and is not particularly limited, but is usually 0°C to 30°C.
This is preferably carried out. 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 N-thienylmethyl-2-(4-chloro-3,
Synthesis of 5-dimethylphenoxy)-butyramide (Compound number 15 in Table 1 below) 1.6 g (0.014 mol) of 2-aminomethylthiophene and 1.4 g (0.014 mol) of triethylamine were dissolved in 50 ml of benzene, and the mixture was heated at room temperature. , 2-(4
-chloro-3,5-dimethylphenoxy)-butyroyl chloride 3.1 g (0.012 mol) of benzene
20ml solution was added dropwise. After stirring for 1 hour and standing overnight, 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 with ethanol to obtain 3.0 g of colorless acicular N-thienylmethyl-2-(4-chloro-3,5-dimethylphenoxy)-butyramide with a melting point of 105 to 107°C. Ta. Synthesis Example 2 Synthesis of N-(2-pyridylmethyl)-2-(3-chlorophenoxy)-butyramide (see Part 1 below)
Compound number 22 in the table) 2-aminomethylpyridine 1.6 g (0.012 mol)
and 1.2 g (0.012 mol) of triethylamine were dissolved in 50 ml of toluene, and 2.8 g of 2-(3-chlorophenoxy)-butyroyl chloride was added to the solution under stirring at room temperature.
(0.012 mol) in 20 ml of toluene solution was added dropwise. 4
After reacting for an hour, the reaction solution was washed with water, diluted caustic soda, and water in this order, and the toluene layer was dehydrated, and then the toluene was distilled off. The obtained oil was purified by column chromatography, and a pale yellow oily liquid with n ²⁶ _D 1.5610 was obtained.
(2-pyridylmethyl-2-(3-chlorophenoxy)-butyramide 2.3g Synthesis example 3 Synthesis of N-furifuryl-2-(4-chloro-3-methylphenoxy)-butyramide (compound No. 11 in Table 1 below) ) 1.5 g (0.015 mol) of frifurylamine and 4.0 g (0.051 mol) of pyridine were dissolved in 50 ml of benzene, and 3.0 g of 2-(4-chloro-3-methylphenoxy)-butyroyl chloride was dissolved in 50 ml of benzene at room temperature with stirring.
(0.012 mol) in benzene (20 ml) was added dropwise, and the mixture was further stirred for 5 hours. After treatment according to Synthesis Examples 1 and 2, the obtained crude crystals were recrystallized from ethanol to obtain N-furfuryl-2-(4-chloro-3-methylphenoxy) in the form of light brown needles with a melting point of 100-102°C. )-butyramide (1.0 g) was obtained. Table 1 lists examples of novel amide 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] When the amide derivative of phenoxyalkanoic acid in this invention is used as a herbicide, it can be formulated into granules, powders, etc. using inert solid carriers, liquid carriers, emulsifying dispersants, etc., in accordance with the practice of agricultural chemical formulations. It can be used in any dosage form, such as emulsion, wettable powder, tablet, aerosol, or smoke. Examples of these inert carriers include talc, clay, kaolin, diatomaceous earth, calcium carbonate, potassium chlorate, saltpetre, wood flour, nitrocellulose, starch, benzene, xylene, n-hexane, gum arabic, vinyl chloride, Examples include carbon dioxide gas, freon, propane, butane, etc. Further, auxiliary agents for formulation, such as spreading agents, diluents, surfactants, solvents, etc., may be appropriately added. Additionally, fungicides, insecticides and other pesticides, urea,
ammonium sulfate, ammonium phosphorous, potassium salts and other fertilizer substances,
It can be used by appropriately mixing it with a soil conditioner. The amount of herbicide used in this invention varies slightly depending on the method of use, place of use, type of target weed, etc., but the amount of the active ingredient, i.e., the amide derivative of phenoxyalkanoic acid, is 0.5 to 0.5 per are.
It is recommended to use 100 g, preferably 1 to 50 g. Next, examples of the herbicide of this invention will be given. Note that parts in each example indicate parts by weight. Example 1 50 parts of N-thienylmethyl-2-(3,4-dichlorophenoxy)-butyramide (compound No. 34), 40 parts of xylene, and 10 parts of Solpol 800 (surfactant, trade name) were mixed. An emulsion was obtained by melting. Example 2 50 parts of N-(2-pyridylmethyl)-2-(4-chloro-3,5-dimethylphenoxy)-butyramide (compound No. 16), 30 parts of kaolin,
15 parts bentonite, 5 parts sodium lignin sulfonate
A wettable powder was obtained by mixing and pulverizing a portion. Example 3 7 parts of N-furfuryl-2-(4-chloro-3-methylphenoxy)-butyramide (compound No. 11), 60 parts of bentonite, 30 parts of talc,
After mixing and pulverizing 3 parts of sodium naphthalene sulfonate, an appropriate amount of water was added and the mixture was 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. The test compound numbers in each example are the same as the compound numbers 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 japonica), firefly, and cypress are uniformly mixed and sown on the surface layer.
1. Transplant paddy rice seedlings at the 8-2 leaf stage, add water and
The water was flooded to a depth of cm. Then, three days later, at the beginning of the emergence of various weeds, a predetermined amount of diluted solutions 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: Complete withering 4: Severe damage 3: Medium damage 2: Small damage 1: Slight damage 0: No harm (normal growth) In addition, the upper row of each column in Table 2 indicates the active ingredient amount: 50 g/are, and the lower row: 25 g. / Shows the results of an experiment conducted with R.

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[Table] Anilide experiment example 2 Stalk and foliage spraying test Field soil (diluvial soil) in a 1/15500 are pot
After the filling, wheat, edible barnyard grass, crabgrass, and blueberry were sown. When each plant had grown to 2 to 3 leaves, each hydrating powder produced according to Example 2 was
0.50wt% and 0.25wt% aqueous solutions were sprayed using a pressure sprayer. Two weeks after the treatment, the herbicidal effects of each test compound were investigated. The results are shown in Table 3. The criteria for the herbicidal effect in Table 3 are the same as in Experimental Example 1. The upper row of each column in Table 3 shows the results of experiments conducted at an active ingredient concentration of 0.50 wt%, and the lower row shows the results of experiments conducted at 0.25 wt%.

[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, a halogen atom or a nitro group, n represents 0, 1, 2 or 3, R represents a lower alkyl group having 2 or 3 carbon atoms, Y represents a furyl group, An amide derivative of phenoxyalkanoic acid represented by a thienyl group, pyridyl group or naphthyl group. 2 General formula (However, in the formula, X represents a lower alkyl group or a halogen atom, and n represents 0, 1, 2 or 3,
R represents a lower alkyl group having 2 or 3 carbon atoms,
Y represents a furyl group, a thienyl group, a pyridyl group or a naphthyl group. A herbicide characterized by containing an amide derivative of phenoxyalkanoic acid represented by ) as an active ingredient.