JPH0480023B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to general formula (I) (In the formula, X represents a chlorine atom or a bromine atom, and R represents an alkyl group substituted with a halogen atom.) It is a herbicide that The present inventors have continued research into herbicides with highly selective herbicidal efficacy in order to protect important crops such as soybean, cotton, wheat, corn, and rice from weed damage and maintain high yields. Ta.
As a result, it was discovered that the tetrahydroisoindole derivative represented by the general formula (I) exhibits extremely high herbicidal efficacy, particularly in the post-emergence treatment of upland weeds, and has a high degree of selectivity for soybean. The invention has been completed. It is a well-known fact from numerous patents and literature that phenoxyacetic acid derivatives have strong herbicidal efficacy. However, some of these known phenoxyacetic acid derivatives have 4,5,6,7 on the phenyl nucleus.
- There is no one having a tetrahydroisoindole group, and no description regarding it has been made. On the other hand, it is described in Japanese Patent Publication No. 11940/1983 that 2-phenyl-4,5,6,7-tetrahydro-2H-isoindole derivatives have herbicidal activity. However, nothing is described regarding phenoxyacetic acid derivatives. As will be clear from the later examples, the compounds of the present invention are derived from conventionally known phenoxyacetic acid derivatives (for example, 2,4,5-T) and 2-phenyltetrahydro-2H-isoindole derivatives (such as 2-phenyltetrahydro-2H-isoindole derivatives). It has superior properties compared to compounds (A) and (B)).
The compounds of the present invention exhibit high herbicidal efficacy against upland weeds in pre- and post-emergence treatments, and have excellent properties that cause little harm to soybean, wheat, corn, etc. In particular, when the compound of the present invention is used as a post-emergence treatment, it is extremely effective against broad-leaved weeds such as morning glory, Japanese sagebrush, Japanese purslane, purslane, American hornwort, black-and-white weed, and blue-leaved weed, which are important weeds in soybean fields, and is effective against soybean. As is clear from the examples, it is characterized by being less harmful and exhibiting high soybean selectivity, and is expected to be used in soybean fields. The compound of the present invention can also be used in paddy fields, various grains, vegetables, orchards, lawns, pastures,
It is also useful as a herbicide for tea gardens, mulberry gardens, rubber gardens, forest land, non-agricultural land, etc. Next, a method for synthesizing the compound of the present invention will be described. The compound of the present invention can be obtained according to the following reaction formula. (In the formula, X and R are as described above, and Y represents a chlorine atom, a bromine atom, or an iodine atom.) In a solvent such as hexamethyltriamide, in the presence of a dehydrohalogenating agent, such as a salt such as sodium carbonate or potassium carbonate, a metallating agent such as sodium hydride or sodium aukoxide, or an organic base such as a tertiary amine, It can be synthesized by reacting with an α-haloacetic acid haloalkyl ester represented by the general formula () at 20 to 100°C, preferably 30 to 60°C. Next, Examples will be shown to provide a more detailed explanation of the compounds of the present invention. Example 1 2-{4-chloro-2-fluoro-5-(2-chloroethoxycarbonylmethoxy)phenyl}
-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione (compound number (2)) 2-(4-chloro-2-fluoro-5-hydroxyphenyl)-4,5, 6,7-tetrahydro-2H-isoindole-1,3-dione 3
g was dissolved in 20 ml of dimethylformamide, and 0.8 g of anhydrous potassium carbonate was added. Furthermore, 2.1 g of bromoacetic acid-2-chloroethyl ester was added,
Stirred at 40-50°C for 3 hours. After cooling, water was added, extracted with toluene, washed with water, dried over anhydrous magnesium sulfate, and concentrated. The residue was purified by silica gel column chromatography to obtain 1.4 g of colorless oil. The compounds shown in Table 1 were synthesized in the same manner as in Example 1.

[Table] When actually using the compound of the present invention, it is recommended to formulate it into an easy-to-use form such as an emulsion, wettable powder, suspension agent, granule, or powder according to the conventional method in the agricultural chemical formulation field. Common. In this case, the content of the compound of the present invention in each preparation is 0.1 to 90%, preferably 1 to 80%. Examples of solid carriers used in preparing these pharmaceutical products include kaolin, bentonite, talc, diatomaceous earth, ziecrite, and synthetic hydrous silicon oxide. Liquid carriers include aromatic hydrocarbons such as xylene and methylnaphthalene, cyclohexanone,
Examples include ketones such as isophorone, chlorobenzene, dimethylformamide, cellosolve, ethylene glycol, and water. Examples of surfactants used for purposes such as emulsification, dispersion, and spreading include polyoxyethylene alkyl ether, polyoxyethylene alkylaryl ether, polyoxyethylene styryl aryl ether, polyoxyethylene resin acid ester, and polyoxyethylene. Examples include nonionic surfactants such as sorbitan fatty acid esters and oxyethylene oxypropylene polymers, and anionic surfactants such as alkyl sulfate ester salts, alkyl sulfonates, dialkyl sulfosuccinates, and alkylaryl sulfonates. They may be used alone or in combination. Furthermore, if necessary, a lignin sulfonate, polyvinyl alcohol, or a cellulose derivative such as methyl cellulose can be used as an adjuvant. Of course, the carriers, surfactants, etc. that can be used are not limited to those shown here. Next, a detailed explanation will be given by giving a formulation example, but it goes without saying that the formulation ratio and carrier can be changed. Note that parts in each example indicate parts by weight. Formulation Example 1 80 parts of compound (7), 5 parts of polyoxyethylene alkylaryl ether, and 15 parts of synthetic hydrated silicon oxide are thoroughly ground and mixed to obtain a wettable powder. Formulation Example 2 10 parts of compound (4), 7 parts of polyoxyethylene alkylaryl ether, 3 parts of alkylaryl sulfonate and 80 parts of cyclohexanone are thoroughly mixed to obtain an emulsion. Compounding agent 3 1 part of compound (7), 1 part of synthetic hydrous silicon oxide, 5 parts of lignin sulfonate and 93 parts of clay are thoroughly ground and mixed, water is added and the mixture is thoroughly kneaded and then granulated and dried to obtain granules. . Formulation Example 4 3 parts of compound (3), 0.5 parts of isopropyl phosphate, 66.5 parts of clay and 30 parts of talc are thoroughly ground and mixed to obtain a powder. Formulation Example 5 20 parts of compound (5) was mixed with 60 parts of an aqueous solution containing 3% by weight of polyoxyethylene sorbitan monooleate, wet-pulverized until the particle size of the active ingredient was 3μ or less, and alginic acid was added as a dispersion stabilizer. A suspension preparation is obtained by mixing 20 parts of an aqueous solution containing 3% by weight of sodium. When the compound of the present invention is used either before or after germination, the application rate can vary over a fairly wide range, but is usually 0.01 to 100 g per are;
Preferably it is 0.1-30g. Furthermore, the compound of the present invention can be mixed with other herbicides in order to improve its effectiveness as a herbicide, and in some cases, a synergistic effect can be expected. Furthermore, the compound of the present invention can be mixed with insecticides, nematicides, plant growth regulators, fertilizers, etc., if necessary. Next, the compounds of the present invention will be explained in more detail by giving examples related to herbicidal efficacy. Note that control compounds in Examples are listed in Table-2. All evaluations of chemical damage to crops and efficacy against weeds in the following Examples were expressed as evaluation values using integers from 0 to 5 in accordance with the criteria described below. The dry weight of the above-ground parts of the plants that remained withered at the time of the survey was measured, and the ratio (%) compared to the untreated area was calculated. The chemical damage and herbicidal efficacy of crops and weeds are evaluated from 0 to 5 based on the criteria shown in the table below.
Evaluated by numbers up to.

[Table] Example 2 Field-like foliage treatment test A vat with an area of 33 x 23 cm ² was filled with field soil, and seeds of Aspergillus japonica, Ichibi, Japanese fir tree, and soybean were sown and allowed to grow for 18 days. Thereafter, each compound was formulated into an emulsion, a predetermined amount was diluted with water, and the mixture was uniformly applied from the top of the plant to the entire stem and leaf area using a small sprayer. The amount of water sprayed was set at a ratio of 10/a. The growth status of each weed at the time of treatment differed slightly depending on the grass species, but it was generally in the 2-4 leaf stage and the plant height was 2-12 cm. Twenty days after treatment, the herbicidal efficacy and crop damage of each compound were investigated. The results are shown in Table-3. This test was conducted in a greenhouse throughout the entire period.

【table】

[Table] Example 3 Field soil treatment test A 1/5000a Wagner pot was filled with field soil, and seeds of morning glory, Japanese crocodile, blueberry, soybean, and corn were sown and covered with soil to a thickness of 1 cm. Thereafter, a predetermined amount of the compound formulated into an emulsion was diluted in water and sprayed onto the soil surface using a small sprayer. The amount of water sprayed was set at a ratio of 10/a. After 3 weeks in the open air, the herbicidal efficacy and crop damage of each compound were investigated. The results are shown in Table 4.

【table】

【table】

Claims (1)

[Claims] 1. General formula (In the formula, X represents a chlorine atom or a bromine atom, and R represents an alkyl group substituted with a halogen atom.) N-phenyltetrahydro-2H-isoindole derivatives. 2 α-Haloacetic acid haloalkyl ester represented by the general formula YCH ₂ CO ₂ R (wherein Y represents a chlorine atom, bromine atom, or iodine atom, and R represents an alkyl group substituted with a halogen atom) and the general formula (In the formula, X represents a chlorine atom or a bromine atom.) A general formula characterized by reacting a phenol derivative represented by the following in the presence of a dehydrohalogenating agent: (In the formula, X and R are as described above.) A method for producing an N-phenyltetrahydro-2H-isoindole derivative represented by the following formula. 3 General formula (In the formula, X represents a chlorine atom or a bromine atom, and R represents an alkyl group substituted with a halogen atom.) herbicide. 4. The herbicide according to claim 3, wherein the herbicide is a soybean herbicide.