JPS5814402B2 - old man - Google Patents

Description

[Detailed description of the invention] The present invention relates to a novel herbicide useful in agriculture and horticulture.

More specifically, the present invention relates to phenoxyphenoxyalkanecarboxylic acids represented by the general formula (wherein X is a hydrogen atom or a methyl group, and Y is a chlorine atom, a bromine atom, or a cyano group), and its alkali metal Or, it is a herbicide characterized by containing an alkaline earth metal salt or a lower alkyl ester as an active ingredient.

Examples of the salts of the phenoxyphenoxyalkane carboxylic acids include salts such as sodium salts, potassium salts, and calcium salts of the alkane carboxylic acids;
Examples of the lower alkyl ester of the phenoxyphenoxyalkane carboxylic acid include a wide range of esters such as methyl ester, ethyl ester, iso-propyl ester, and n-butyl ester.

The main effects brought about by the herbicide of the present invention are as follows.

That is, when used in fields, (1) foliage treatment can kill harmful weeds even at low concentrations.

(2) The growth inhibitory effect on broad-leaved plants is stronger than that on grasses, and therefore broad-leaved noxious weeds can be selectively controlled in areas where grasses such as wheat and rice are cultivated.

(3) In soil treatment, it is not inferior to conventional herbicides of the same chemical structure.

Shows excellent weed control effect.

In addition, when used in paddy fields, (4) it exhibits sufficient control effects against harmful weeds that have begun to proliferate in recent years, such as Japanese grasshopper and Japanese firefly (5) it does not substantially harm rice plants; It has intergeneric selectivity to control grasses.

The herbicidal compound of the present invention is generally produced by the following method.

(1) 2-chloro or bromo or 2-cyano-5-(2-chloro-4-trifluoromethylphenoxy)phenol is added with monohaloacetic acid ester or α-halopropionic acid ester in the presence of an alkali to a concentration of 30 to 15
The reaction is carried out at 0° C. for 0.5 to 7 hours to obtain an ester of 2-chloro or bromo or 2-cyano-5-(2-chloro-4-trifluoromethylphenoxy)phenoxyalkanecarboxylic acid.

(2) 2-halo 5-(2-chloro-4-trifluoromethylphenoxy) phenoxyalkanecarboxylic acid ester is reacted with cuprous cyanide at 120 to 170°C for 1 to 5 hours, 2-cyano-5-(2-chloro-4-trifluoromethylphenoxy)phenoxyalkanecarboxylic acid ester is obtained.

(3) 2-Amino-5-(2-chloro-4-trifluoromethylphenoxy)phenoxyalkanecarboxylic acid ester is diazotized to obtain a diazonium salt, which is then treated with cuprous chloride-containing hydrochloric acid or dichloromethane. 1 copper-containing hydrobromic acid from 20 to
React at 100°C for 0.5 to 2 hours to obtain 2-chloro or bromo 5-(2-chloro-4-trifluoromethylphenoxy)phenoxyalkanecarboxylic acid ester, or to the diazonium salt. Alkali cyanide and copper sulfate are reacted at 20 to 100°C for 0.5 to 2 hours to obtain 2-cyano-5-(2-chloro-4-trifluoromethylphenoxy)phenoxyalkanecarboxylic acid ester. .

(4) Although the above-mentioned production methods are for esters, these methods can also be applied almost directly to the production of acids and salts.

Furthermore, compounds of the above general formula can also be obtained by converting the acids, esters, and salts thus obtained into other acids, esters, and salts according to conventional methods.

Next, a specific synthesis example of the herbicidal compound of the present invention will be described.

Synthesis Example l Synthesis of α-{2-bromo-5-(2-chloro-4-to-2-trifluoromethylphenoxy)phenoxy}furopionic acid methyl ester 187 (enoxy)phenol and 12.5 g of α-bromopropionic acid methyl ester were dissolved in 40 ml of methyl ethyl ketone, 77 g of anhydrous potassium carbonate was added thereto, and the mixture was reacted under reflux with stirring for 2 hours.

The product was poured into water to obtain a precipitate, which was extracted with chloroform.

The extract was washed with water, dried, and further distilled under reduced pressure after distilling off chloroform, b, p, 185-186°C/2.
17 g of the target product was obtained at 5 mmHg.

Synthesis Example 2 Synthesis of α-{2-cyano-5-(2-chloro-4-trifluoromethylphenoxy)phenoxy}propionic acid methyl ester α-{2-bromo-5-(2-chloro-
4-Trifluoromethylphenoxy)phenoxy}propionic acid methyl ester 107 was dissolved in 15 ml of dimethylformamide, 2.47 ml of cuprous cyanide was added, and the mixture was reacted under reflux for 5 hours with stirring.

The reaction product is poured into an aqueous ferric chloride solution to obtain a precipitate,
This was extracted with chloroform.

The extract was dried, chloroform was distilled off, and then distilled under reduced pressure to obtain b, p. 1 8 9-192°C/1.5 mmHg target product 7.57 was obtained.

Next, specific examples of the herbicidal compound of the present invention will be described.

2-Bromo 5-(2-chloro-4-trifluoromethylphenoxy)phenoxyacetic acid methyl ester b,p,1 8 5-190℃/2mmHgα-{2-
Bromo 5-(2-chloro-4-trifluoromethylphenoxy)phenoxy}propionic acid m. p, IO 9 ~1 20°C α-{2-bromo5-(2-chloro4-trifluoromethylphenoxy)phenoxy}propionic acid methyl ester b. p. 185-186°c/2. 5mmHg
2-cyano 5-(2-chloro-4-trifluoromethylphenoxy) phenoxyacetic acid methyl ester m, p, 137 to 140°C α-{2-cyano 5-(2-chloro-4-trifluoromethylphenoxy) enoxy)phenoxy}propionic acid m, p, 128-133℃ α-{2-cyano5-(2-chloro-4-trifluoromethylphenoxy)phenoxy}propionic acid sodium salt α-{2-cyano5 -(2-chloro4-trifluoromethylphenoxy)phenoxy}propionic acid methyl ester b, p, 1 8 9-192℃/1.5mmHgα
-{2-cyano-5-(2-chloro-4-trifluoromethylphenoxy)phenoxy}prohyonic acid ethyl ester b, p. 200-205°C/3mmHg2-chloro5-(2-chloro4-trifluoromethylphenoxy)phenoxyacetic acid methyl ester m. p, 106-108°C α-{2-chloro-5-(2-chloro-4-trifluoromethylphenoxy)phenoxy} propionic acid methyl ester b, p, 1 6 7-170°C/2mmHgα-{
2-bromo 5-(2-chloro-4-trifluoromethylphenoxy)phenoxy}propionic acid ethyl ester b, p, 200-205℃/3mm Hg2-bromo 5-(2-chloro-4-trifluoromethylphenoxy) phenoxy) phenoxyacetic acid m. p, 83-89°C 2-cyano-5-(2-chloro-4-trifluoromethylphenoxy) phenoxyacetic acid m, p. 9 1 to 97°C Considering its effectiveness, the herbicide of the present invention is suitable for selectively killing broad-leaved weeds, especially in fields where grass crops are cultivated. Because it has an excellent weeding effect, it can be applied to a wide range of fields, including fields, orchards, mulberry orchards, rice fields, forests, farm roads, grounds, and factory grounds, and the application method can be selected as appropriate from foliage treatment to soil treatment. .

In addition, depending on the application method, it can be used by dispersing in water, or by adding various auxiliary agents such as diluents, solvents, emulsifiers, and spreading agents to form emulsions, solutions, wettable powders, powders, granules, etc. It can be formulated and used.

In addition to using the herbicide of the present invention alone, it can also be used with other herbicides,
It can be used in combination with agricultural chemicals such as insecticides and fungicides, as well as fertilizers and soil, and in some cases even better effects can be obtained by using these in combination.

The appropriate amount of the herbicide of the present invention to be applied cannot be determined unconditionally due to differences in weather conditions, soil conditions, drug formulation, application timing, application method, type of target weed, etc., but in general, the amount of active ingredient applied per are is 0. .1~100I? , preferably 0.5 to 707.

Next, examples of herbicidal tests and formulations according to the present invention will be described, but of course the present invention is not limited only to these descriptions.

Test Example 1 Soil was placed in a 1/3000 Arubat, and a certain amount of barnyard grass and radish seeds were sown as a field condition, and on top of that, soil containing seeds of common weeds such as crabgrass, cane millet, chickweed, and flea bran was added to the soil. It was covered with soil to a thickness of 1 cm.

An aqueous dispersion of the active ingredient was sprayed on the third day after sowing.

The growth state of the weeds was visually observed on the 20th day after the chemical treatment, and the results shown in Table 1 were obtained.

A value of 10 in the table indicates that growth was completely inhibited, and the degree of growth inhibition was divided into 10 levels below.

Test Example 2 Soil was placed in a 1/10,000 are pot to prepare a field, and a certain amount of barnyard grass, radish, and soybean seeds were sown there and covered with soil to a thickness of about 1 cm.

Thereafter, when the barnyard grass reached the two-leaf stage, an aqueous dispersion of the active ingredient at a predetermined concentration was sprayed so as to uniformly cover the stems and leaves.

The growth condition of each plant was visually observed on the 20th day after the chemical solution treatment, and the degree of growth inhibition was expressed using the same criteria as in Test Example 1 to obtain the results shown in Table 2.

Test Example 3 Soil was placed in a 1/10,000 are pot, impregnated with water to a supersaturated state, and the soil was lightly covered with soil containing a certain amount of weed seeds.

Thereafter, the area was flooded and the water depth was maintained at 3 cm, and on the 7th day, when all weeds had emerged, a predetermined amount of an aqueous dispersion of the active ingredient was sprayed.

The growth state of the weeds was visually observed on the 14th day after the chemical solution treatment, and the results shown in Table 3 were obtained.

A value of 5 in the table indicates that growth was completely inhibited, and the degree of growth inhibition was divided into five levels below.

Example 1 (1) α-{2-cyano-5-(220 parts by weight 1-chloro-4-trifluoromethylphenoxy)phenoxy} Propionate methyl ester (2) Xylene 60〃(3)
Solpol 2806B 20 (trade name: manufactured by Toho Chemical Industry Co., Ltd.) The above components were uniformly mixed to obtain a herbicide (emulsion) of the present invention.

Example 2 (1) Zeeklite 78 parts by weight (2) Labelin S 2 parts by weight (Product name: Daiichi Kogyo Seiyaku Co., Ltd.) (3) Solpol 5039 5// (Product name: Toho Chemical Co., Ltd.) (4) Carplex ■5 〃(
Product name: Shionogi Pharmaceutical Separation) A mixture of the above components (1) to (4) and methyl α-{2-bromo5-(2-chloro-4-trifluoromethylphenoxy)phenoxy}propionate The herbicide (wettable powder) of the present invention was obtained by mixing the esters in a weight ratio of 4:1.

Claims (1)

[Claims] 1 Phenoxyphenoxyalkanecarboxylic acid represented by the general formula (wherein X is a hydrogen atom or a methyl group, and Y is a salt, a hydrogen atom, a bromine atom, or a cyano group); A herbicide characterized by containing an alkali metal or alkaline earth metal salt, or a lower alkyl ester as an active ingredient.