JPS61109702A - Imidazole based herbicide - Google Patents

Abstract

NEW MATERIAL:A compound expressed by formula I [R<1> represents H, CF3, pyridyl or (nitro-substituted)phenyl; R<2> represents H, CF3 or lower alkyl; m is 0 or 1; n is 1 or 2, provided that n=2 when m=0 and n=1 when m=1, R<1>=R<2>not equal to CF3]. EXAMPLE:4(5)-Nitro-2-trifluoromethylimidazole. USE:An active ingredient of herbicides harving immediate herbicidal effect on gramineous weeds such as barnyard grass and oats, broadleaf weeds such as Pharbitis purpurea Voigt and Indian mallow, commelinaceous weeds such as spiderwort, and used by soil treatment, foliar treatment or treatment under flooding condition as pre- or post-emergence treatment. It is useful as a herbicide for paddy field, upland field, orchard, pasture, turf non-cultivated land, etc. PREPARATION:An imidazole derivative expressed by formula II [R<3> represents H, CF3, pyridyl or (substituted)phenyl, provided that R<3>=R<2>not equal to CF3] is nitrated with fuming nitric acid or concn. nitric acid and concn. sulfuric acid for several min - 30hr at 30-150 deg.C to obtain the compound expressed by formula I.

Description

Detailed Description of the Invention The present invention is based on the general formula [wherein R represents a substituted or unsubstituted phenyl group which may be substituted with a hydrogen atom, a trifluoromethyl group, a pyridyl group, or a nitro group, and R2 is It represents a hydrogen atom, a trifluoromethyl group or a lower alkyl group, m represents 0 or 1, and n represents 1 or 2.

(However, when m is 0, n represents 2, and when m is 1,
n represents 1, and R and R do not represent a trifluoromethyl group at the same time. )] The present invention relates to a nitroimidazole derivative represented by (hereinafter referred to as the compound of the present invention), a method for producing the same, and a herbicide containing the same as an active ingredient.

The compounds of the present invention can be used to treat various weeds that are problematic in the treatment of foliage and earthen walls in fields, such as freckle grass, Japanese knotweed, purslane, chickweed, whiteweed, Japanese radish, Japanese radish, Japanese radish, shepherd's purse, American hornwort, Ebisu grass, Japanese commonweed, Broad-leaved weeds such as golden deer, field pansies, Japanese violets, morning glories, common morning glories, European bindweed, Japanese oatweeds, hotokenoza, Japanese morning glories, Japanese Physalis, Japanese dogfish, Japanese fir trees, sunflowers, dog mottles, corn marigolds, barnyard grass, and Japanese commonweeds. , weeds of the grass family such as foxtail grass, blackberry grass, sycamore, grasshopper, oat, oat, seiban sorghum, sorghum, grasshopper, and sorghum, and weeds of the family Asiatic family such as dayflower,
It has a herbicidal effect against weeds of the Cyperaceae family, such as Cyperus japonica and Cyperaceae. Moreover, its feature is that it is fast-acting.

The compound of the present invention has the general formula [1, where R8 represents a hydrogen atom, a trifluoromethyl group, a pyridyl group, or a substituted or unsubstituted phenyl group, and R2 and m have the same meanings as above. (however,
R and R do not simultaneously represent a trifluoromethyl group. )] imidazole derivative and fuming nitric acid,
Or add a mixed acid of concentrated nitric acid and concentrated sulfuric acid for several minutes to 80 hours.
React at 0 to 150°C, preferably 80 to 120°C,
It can be produced by nitration.

The reaction solution after the completion of the reaction can be subjected to the usual post-treatment for this type of nitration reaction to obtain the desired compound of the present invention. Further, if necessary, it is purified by operations such as chromatography and recrystallization.

In general formula [1[], the substituted phenyl group represented by R8 includes a halogen-substituted phenyl group, a lower alkylcarbonyl-substituted phenyl group, a nitro-substituted phenyl group, a carboxy-substituted phenyl group, a lower alkoxy-substituted phenyl group,
Examples include a lower alkyl-substituted phenyl group, a lower alkylamino-substituted phenyl group, a hydroxy-substituted phenyl group, a lower alkylthio-substituted phenyl group, an amino-substituted phenyl group, a phenoxy-substituted phenyl group, and the like.

In addition, in the nitration reaction of the imidazole derivative [II], when R8 is a substituted or unsubstituted p-nyl group, the phenyl nucleus may be nitrated by selecting the above reaction conditions.

Next, production examples of the compounds of the present invention will be shown.

Production example 1 2-trifluoromethylimidazole 1.091 to 94
The mixture was placed in a mixed acid consisting of 5% fuming nitric acid and 96% concentrated sulfuric acid and heated for 10 minutes until gently refluxed. The mixture was poured into ice-cold water, neutralized with a 20% aqueous sodium hydroxide solution (pH 5 to 6), and extracted eight times with ethyl acetate. After drying the extract over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure. The residue was separated by silica gel column chromatography (eluent: ether) and 2% nitro
Trifluoromethylimidazole 671 (yield 46.
8%, mp, 210-212 °C1 reconsolidation solvent: ether-benzene) and 4,5-dinitro-2-trifluoromethylimidazole 0.891 (yield 49.2%, m,
9.288-286”C decomposition, reconsolidation solvent: ethyl acetate
benzene) was obtained.

Production example 2 4(5”)-trifluoromethylimidazole 168f
was dissolved in a mixed acid consisting of 94% fuming nitric acid 10- and 96% concentrated sulfuric acid 10- and heated to gentle reflux for 24 hours.

After cooling, the mixture was poured into ice water and neutralized (pH 5 to 6) with a 20% aqueous sodium hydroxide solution. The white solid produced was filtered off, and the filtrate was extracted three times with ethyl acetate. After drying the extract,
The solvent was distilled off under reduced pressure. The resulting residue was combined with a white solid and recrystallized with an ether-ethyl acetate mixed solvent to obtain 0.78 da of 5(4)-nitro-4(5)-trifluoromethylimidazole (yield: 86 ．(M
J, m, 9.190-192°C) was obtained.

Table 1 shows some of the compounds of the present invention that can be produced by such a production method.

Table 1 *Fluorine X-19 nuclear magnetic resonance chemical shift values (acetone-d6 solution, trifluoroacetic acid as external reference, low magnetic field side (as advantage).

When using the compound of the present invention as an active ingredient of a herbicide,
It is usually mixed with solid carriers, liquid carriers, surfactants, and other formulation auxiliaries to formulate emulsions, wettable powders, suspensions, granules, etc.

These preparations contain the compound of the present invention as an active ingredient in a weight ratio of 1 to 90%, preferably 5 to 70%.

Examples of solid carriers include fine powders or granules such as kaolin clay, attapulgite clay, bentonite, acid clay, pyrophyllite, talc, diatomaceous earth, calcite, walnut powder, urea, ammonium sulfate, and synthetic hydrous silicon oxide. Liquid carriers include aromatic hydrocarbons such as xylene and methylnaphthalene, alcohols such as isopropanol, ethylene glycol, and cellosolve, ketones such as acetone, cyclohexanone, and isophorone, vegetable oils such as soybean oil and cottonseed oil, and dimethyl sulfoxide. , dimethylformamide, acetonitrile, water, etc.

Surfactants used for emulsification, dispersion, wetting layers, etc. include anionic surfactants such as alkyl sulfate salts, alkylaryl sulfonates, dialkyl sulfosuccinates, and polyoxyethylene alkylaryl ether phosphate salts. agent, polyoxyethylene alkyl ether, polyoxyethylene alkylaryl ether,
Examples include nonionic surfactants such as polyoxyethylene polyoxypropylene block copolymers, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters. As formulation aids, lignin sulfonate, alginate, polyvinyl alcohol, gum arabic, CMC (carboxymethyl cellulose), PA
Examples include P (isopropyl acid phosphate).

Examples of formulations are shown below. The compounds of the present invention are indicated by compound numbers in Table 1. Parts indicate parts by weight.

Formulation Example 1 1.50 parts of the compound of the present invention, 8 parts of calcium lignosulfonate, 2 parts of sodium lauryl sulfate, and 45 parts of synthetic hydrous silicon oxide are ground and mixed to obtain a wettable powder.

Formulation Example 2 2.10 parts of the compound of the present invention, 14 parts of polyoxyethylene styryl phenyl ether, 6 parts of calcium dodecylbenzenesulfonate, 40 parts of xylene and 80 parts of dimethylformamide are thoroughly mixed to obtain an emulsion.

Formulation Example 8 8.2 parts of the compound of the present invention, 1 part of synthetic hydrous silicon oxide, 2 parts of calcium lignosulfonate, 80 parts of bentonite, and 65 parts of kaolin clay were thoroughly ground and mixed, water was added, and the mixture was thoroughly kneaded. The granules are dried to obtain granules.

Formulation Example 4 4.25 parts of the compound of the present invention, 8 parts of polyoxyethylene sorbitan monooleate, 8 parts of CMC, and 69 parts of water are mixed and wet-pulverized until the particle size becomes 5 microns or less to obtain a suspension.

Formulation Example 5 5.10 parts of the compound of the present invention, 1 part of polyoxyethylene styrylphenyl ether, and 89 parts of water are mixed to obtain a liquid preparation.

The compound of the present invention thus formulated is treated with soil, foliage, or flooding before or after the emergence of weeds. Soil destruction treatments include soil surface treatments, soil wall mixing treatments, etc. Stalk and foliage treatments include treatments from above the plant body as well as local treatments that treat only weeds so that they do not attach to crops.

Furthermore, by mixing it with other herbicides, it can be expected to increase the herbicidal efficacy. Furthermore, it can be used in combination with insecticides, acaricides, nematicides, fungicides, plant growth regulators, fertilizers, soil conditioners, and the like.

The compound of the present invention can be used in rice fields, fields, orchards, pastures,
It can be used as an active ingredient in herbicides for lawns, forests, non-agricultural lands, etc.

When the compound of the present invention is used as an active ingredient of a herbicide, the amount to be treated will vary depending on weather conditions, formulation form, treatment time, method, location, target weeds, target crops, etc., but usually 1.
51 to 400 f per are, preferably 1 oy to
10Of, and emulsions, wetting agents, suspending agents, etc. are usually used in a specified amount of 1 liter to 10 liters per are (
If necessary, they are diluted with water (to which auxiliary agents such as spreading agents are added), and granules and the like are usually treated as they are without any dilution.

In addition to the above-mentioned surfactants, the spreading agents include polyoxyethylene resin acid (ester), lignin sulfonate,
Examples include abietate, dinaphthylmethane disulfonate, and paraffin.

Next, test examples demonstrate that the compounds of the present invention are useful as active ingredients of herbicides. The compounds of the present invention are indicated by the compound numbers in Table 1, and the compounds used for comparison are indicated by the compound symbols in Table 2.

Table 2 In addition, the herbicidal efficacy was determined by visually observing the degree of budding and growth inhibition of the test plants during the survey, and ``0'' indicates that there was no or almost no difference from the case where the compound was not tested. If the plant is withered or its growth is completely inhibited, it is evaluated as ``5'', and evaluated on a scale of θ to 5, 0.1, 2.
8.4.5.

Test Example 1 Upland Soil Mixture Treatment Test A cylindrical plastic pot with a diameter of 10 cM and a depth of 10 cIn was filled with upland soil, and millet, oat, Marupa morning glory, and Japanese croaker were sown and covered with soil.

Prepare the test compound into an emulsion according to Formulation Example 2, dilute the specified amount with water equivalent to 10 liters per are, and treat the soil surface with a small sprayer. Mixed. After treatment, the plants were grown in a greenhouse for 20 days and their herbicidal efficacy was investigated. The results are shown in Table 8.

Table 8 Test Example 2 Field field stem and leaf treatment test Filled with cylindrical plastic hot field soil of diameter 10 crn 1 depth 10 crl, millet, oat, radish,
Ichibi was sown and grown in a greenhouse for 10 days. after that,
The test compound was made into a hydrating powder according to Formulation Example 1, a predetermined amount of the hydrating powder was diluted with water containing a spreading agent equivalent to 10 liters per are, and the foliage was treated from above the plant using a small sprayer. After treatment, the plants were grown in a greenhouse for 20 days and their herbicidal efficacy was investigated. The results are shown in Table 4.

Table 4 Test Example 8 Field ground stem leaf treatment test area 88 x 28. ffl, filled with field soil in a vat with a depth of 11 cWI, soybean, cotton, sugar beet, morning glory, Japanese fir tree, Japanese crocus, corn, wheat,
Sowing golden millet, Seiban sorghum, and hackberry;
It was grown for 18 days. Thereafter, the test compound was made into a hydrating powder according to Formulation Example 1, a predetermined amount of the powder was diluted with water equivalent to 5 liters per are containing a spreading agent, and a small sprayer was used to spray the leaves and leaves from above the plant body. was uniformly processed. At this time, the growth conditions of weeds and crops vary depending on the grass species, but 1 to 4
At the leaf stage, the plant height was 2 to 123 cm. The herbicidal efficacy was investigated 20 days after the treatment. The results are shown in Table 5. This test was conducted outdoors throughout the period.

Claims (3)

[Claims] (1) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, R^1 is a hydrogen atom, a substituted or unsubstituted phenyl group that may be substituted with a trifluoromethyl group, a pyridyl group, or a nitro group. In the formula, R^2 represents a hydrogen atom, a trifluoromethyl group or a lower alkyl group, m represents 0 or 1, and n represents 1 or 2. (However, when m is 0, n represents 2, and when m is 1, n represents 1, and R^1 and R^2 do not represent a trifluoromethyl group at the same time.) Nitroimidazole derivatives shown. (2) General formula▲ Numerical formula, chemical formula, table, etc.▼ [In the formula, R^2 represents a hydrogen atom, a trifluoromethyl group, or a lower alkyl group, and R^3 represents a hydrogen atom, a trifluoromethyl group, or a pyridyl group. represents a group or a substituted or unsubstituted phenyl group, and m represents 0 or 1. (However, R^2 and R^3 do not represent a trifluoromethyl group at the same time.)] There are general formulas ▲ mathematical formulas, chemical formulas, tables, etc. that are characterized by nitrating the imidazole derivative shown by ▼ [In the formula, R^1 represents a hydrogen atom, a trifluoromethyl group, a pyridyl group, or a substituted or unsubstituted phenyl group which may be substituted with a nitro group, n represents 1 or 2, R^2 and m
has the same meaning as above. (However, when m is 0, n represents 2, and when m is 1, n represents 1, and R^1 and R^2 do not represent a trifluoromethyl group at the same time.) A method for producing the shown nitroimidazole derivatives. (3) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, R^1 is a hydrogen atom, a substituted or unsubstituted phenyl group which may be substituted with a trifluoromethyl group, a pyridyl group, or a nitro group. In the formula, R^2 represents a hydrogen atom, a trifluoromethyl group or a lower alkyl group, m represents 0 or 1, and n represents 1 or 2. (However, when m is 0, n represents 2, and when m is 1, n represents 1, and R^1 and R^2 do not represent a trifluoromethyl group at the same time.) A herbicide characterized by containing the shown nitroimidazole derivative as an active ingredient.