JPH0142257B2 - - Google Patents

Description

[Detailed description of the invention]

This invention is based on the general formula [] (However _, in _the formula, represents an alkoxy group, R ₃ represents a hydrogen atom or a lower alkyl group, Y represents a phenyl group, thienyl group, pyridyl group, or furyl group; the hydrogen atom of the phenyl group is a lower alkyl group, a lower alkoxy group,
It may be substituted with a 3,4-methylenedioxy group or a halogen atom. ), and a herbicide containing this novel amide derivative of phenoxyalkanoic acid as an active ingredient. Herbicides containing phenoxy compounds as active ingredients were the first of today's full-scale herbicides, and have been widely used around the world to this day. It has greatly contributed to labor saving. However, this drug is effective against not only annual weeds (e.g. barnyard grass, broad-leaved weeds) in paddy fields, but also perennial weeds (e.g. Japanese snail, Japanese cypress, firefly).
Although it is highly effective and has a wide herbicidal spectrum as a herbicide, it has the common drawback of causing rice damage such as inhibiting tillering and growth due to its auxin action. 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 an amide derivative of phenoxyalkanoic acid, which is a new compound represented by the above-mentioned general formula [] and which has not been described in the literature. This type of compound exhibits a completely new effect called chlorosis, and can eliminate a wide range of weeds that occur in rice fields, fields, other cultivated land, and non-cultivated land without causing any chemical damage to crops. discovered that it has the ability to selectively kill weeds, and completed this invention. In other words, the herbicide of the present invention not only has an excellent herbicidal effect on various weeds such as Poaceae weeds such as Japanese grasshopper and Japanese grasshopper, and broad-leaved weeds such as Aobifolia and Shiroza, but also has an excellent herbicidal effect on crops such as rice, soybeans, and wheat. is an extremely selective herbicide that has almost no phytotoxicity due to auxin action, which is seen in conventionally known phenoxy herbicides, and is completely free from toxicity to humans, fish and shellfish, and odor. The amide derivative of phenoxyalkanoic acid in this invention can be synthesized, for example, by the following reaction. (However, in the formula, X, Y, R ₁ , R ₂ and R ₃ have the same meanings as above. Z means a chlorine atom or a bromine atom.) The above reaction is carried out using pyridine in the presence of an appropriate solvent. ,
This is preferably carried out by adding a weak alkali such as triethylamine, sodium carbonate or potassium carbonate. Solvents used in the reaction include aromatic carbons such as benzene, toluene, and xylene, ethers such as diethyl ether, tetrahydrofuran, and dioxane, and methyl ethyl ketone.
Examples include ketones such as dimethyl ketone. The reaction temperature varies depending on the type of reagent and solvent used, and is preferably carried out at 0°C to 30°C, although it is not particularly limited. The reaction is completed in about 1 to 10 hours. Next, an example of its synthesis will be shown. Synthesis Example 1 Synthesis of N-(2-chlorobenzyl)2-(3-trifluoromethylphenoxy)-butyramide (compound No. 29 in Table 1 below) 2-chlorobenzylamine 1.6 g (0.011 mol)
and 1.0 g (0.013 mol) of pyridine were dissolved in 50 ml of toluene, and 2.5 g of 2-(3-trifluoromethylphenoxy)-butyroyl chloride was dissolved in 50 ml of toluene at room temperature with stirring.
A solution of 0.009 mol) in 20 ml of toluene 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 toluene layer was dehydrated, and then the toluene was distilled off. The obtained crude crystals were recrystallized with ethanol, and the melting point was
1.7 g of colorless acicular N-(2-chlorobenzyl)-2-(3-trifluoromethylphenoxy)-butyramide exhibiting a temperature of 66 to 68°C was obtained. Synthesis Example 2 Synthesis of N-benzyl-2-(4-chloro-3-trifluoromethylphenoxy)-butyramide (compound No. 46 in Table 1 below) 1.6 g (0.015 mol) of benzylamine and pyridine
Dissolve 2.4g (0.030mol) in 50ml of toluene,
According to Synthesis Example 1, a solution of 3.0 g (0.010 mol) of 2-(4-chloro-3-trifluoromethylphenoxy)-butyroyl chloride in 30 ml of toluene was added dropwise and treated. The obtained crude crystals were recrystallized with ethanol, and the melting point was
Colorless acicular N-benzyl-2- exhibiting temperature of 93-95℃
1.6 g of (4-chloro-3-trifluoromethylphenoxy)-butyramide was obtained. Synthesis Example 3 Synthesis of N-(4-pyridylmethyl)-2-(4-chloro-3-trifluoromethylphenoxy)-butyramide (compound No. 67 in Table 1 below) 4-(aminomethyl) 1.3 g (0.012 mol) of pyridine and 1.0 g (0.010 mol) of triethylamine were dissolved in 50 ml of toluene, and 2-(4-
Chlor-3-trifluoromethylphenoxy)-
A solution of 3.0 g (0.010 mol) of butyroyl chloride in 30 ml of toluene was added dropwise, and the mixture was treated in accordance with Synthesis Example 1. The obtained oil was purified using a silica gel column by eluting with toluene. 1.6 g of N-(4-pyridylmethyl)-2-(4-chloro-3-trifluoromethylphenoxy)-butyramide was obtained as a pale yellow oil having an n ¹⁹ _D of 1.5228. 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. These inert carriers include talc, clay, kaolin, diatomaceous earth, calcium carbonate, potassium chlorate, saltpeter, wood flour, nitrocellulose, starch,
Examples include benzene, xylene, n-hexane, gum arabic, vinyl chloride, carbon dioxide, freon, propane, and butane. 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. 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-benzyl-2-(3-trifluoromethylphenoxy)-butylamide, 40 parts of xylene,
An emulsion was obtained by mixing and melting 10 parts of Solpol 800 (surfactant, trade name). Example 2 50 parts of N-benzyl-2-(4-chloro-3-trifluoromethylphenoxy)-butyramide,
A wettable powder was obtained by mixing and pulverizing 30 parts of kaolin, 15 parts of bentonite, and 5 parts of sodium ligninsulfonate. Example 3 7 parts of N-furfuryl-2-(4-chloro-3-trifluoromethylphenoxy)-butyramide,
After mixing and pulverizing 60 parts of bentonite, 30 parts of talc, and 3 parts of sodium naphthalene sulfonate, the mixture was mixed with an appropriate amount of water and granulated 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 Flooded soil treatment test A 1/9000 are pot was filled with paddy soil (diluvial soil), and the seeds of various weeds such as grasshopper, broadleaf (kikashigusa, azalea, and cypress), scallops, and cypress were evenly distributed on the surface layer. Mix and sow the
Cyperus tubers were planted and paddy rice seedlings at the 1.8 to 2 leaf stage were transplanted. Thereafter, the area was flooded to a depth of about 2 cm, and at the beginning of weed germination (3rd day after sowing), a predetermined amount of a diluted wettable powder solution of each compound 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 amount of active ingredient.
The results of the experiment were conducted at 25 g/are, and the lower row shows the results at 12.5 g/are.

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[Table] Experimental example 2 Field soil treatment test Field soil (diluvial soil) in a 1/5000 are pot
Filled with soybeans, wheat, wild grass, crabgrass,
After sowing and covering with soil, a predetermined amount of a diluted solution of each 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 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 using an active ingredient amount of 25 g/are, and the lower row shows the results of experiments conducted with an amount of 12.5 g/are.

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

Claims (1)

[Claims] 1. General formula (However _, in _the formula, group, R ₃ represents a hydrogen atom or a lower alkyl group, Y represents a phenyl group, a thienyl group,
Indicates a pyridyl group, a furyl group, and the hydrogen atom of the phenyl group is a lower alkyl group, a lower alkoxy group, 3,
It may be substituted with a 4-methylenedioxy group or a halogen atom. ) Amide derivative of phenoxyalkanoic acid. 2 General formula (However _, in _the formula, represents an alkoxy group, R ₃ represents a hydrogen atom or a lower alkyl group, Y represents a phenyl group, thienyl group, pyridyl group, or furyl group; the hydrogen atom of the phenyl group is a lower alkyl group, a lower alkoxy group,
It may be substituted with a 3,4-methylenedioxy group or a halogen atom. A herbicide characterized by containing an amide derivative of phenoxyalkanoic acid represented by ) as an active ingredient.