JPS59167571A - Benzylsulfinylpyridin-n-oxide derivative, its preparation and herbicide containing it as active ingredient - Google Patents

Abstract

NEW MATERIAL:A benzylsulfinylpyridin-N-oxide derivative shown by the formula I (X is Cl or Br). EXAMPLE:5-Chloro-2-(2,6-difluorobenzylsulfinyl)pyridin-N-oxide. USE:A herbicide. Showing herbicidal effect on various kinds of weeds in paddy fields such as Echinochloa oryzicola Vasing, bulrush, slender spikerush, etc., not providing rice plant with phytotoxicity, exhibiting herbicidal effect on many weeds even by soil treatment before germination of plowed fields. An application amount is 0.1-200g/a, calculated as an amount of effective component. PREPARATION:A benzylthiopyridine derivative shown by the formula II is reacted with an oxidizing agent such as metachloroperbenzoic acid, H2O2, etc. optionally in a solvent at a temperature between a solidification point of the solvent and its boiling point for 30min-10hr, and oxidized to give a compound shown by the formula I .

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is based on the general formula [wherein X represents a chlorine atom or a bromine atom]. ] The present invention relates to a benzylsulfinylpyridine-N-oxide derivative (hereinafter referred to as the compound of the present invention) represented by the formula (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.

Certain pyridine-N-oxide derivatives, Example 1. ;l
', 2-(2,5-dimethylbenzylsulfonyl)pyridine-N-oxide, 5-bromo-2-(2,6-cyclopenzylsulfonyl)pyridine-N-oxide, 5
-Chloro-2-(2,5-dimethylbenzylsulfinyl)pyridine-N-oxide and the like are used as active ingredients of herbicides in U.S. Pat. No. 4,019,898, European Patent No. 86,688 and It is described in JP-A-57-1.81059. However, these compounds cannot always be said to be sufficient as active ingredients for herbicides.

The compound of the present invention can be applied to various weeds in paddy fields, such as Japanese millet, azalea, staghorn grass, Japanese grasshopper, firefly,
It has a herbicidal effect on rice plants, etc., and does not cause any harmful effects on rice. In addition, it has a herbicidal effect on many weeds even in pre-emergence soil treatment in fields.

The compound of the present invention has the general formula [wherein, X represents the same meaning as described above]. ] The benzylthiopyridine-N-oxide derivative represented by It can be produced by oxidation with a group peracid or the like. Although it is not necessary to use a solvent,
When used, it depends on the type of oxidizing agent, for example, for hydrogen peroxide, use water, glacial acetic acid, acetone, etc. For aromatic peracids, use chloroform, halogenated hydrocarbons such as methylene chloride, ethers such as diethyl ether, dioxane, etc. is preferred. In the case of aliphatic peracids, it is preferable to use the oxidizing agent itself in excess.

The oxidizing agent is usually used in an amount of 0.5 to 1.5 equivalents, preferably 0.95 to 1.2 equivalents, per equivalent of benzylthiopyridine-N-oxide derivative [■].

The reaction temperature is from the freezing point to the boiling point of the solvent, preferably 0°C.
to the boiling point of the solvent, and the reaction time is from 80 minutes to 1
It takes about 0 hours. After the reaction is completed, post-treatment is carried out according to a conventional method. If necessary, purify by recrystallization or column chromatography.

Benzylthiopyridine represented by the general formula r n']
N-oxide derivatives are described, for example, in European Patent No. 8
It can be obtained according to the method described in No. 6688.

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

Production Example 1 Production of Compound (1) of the Present Invention 1.5 g of tochloro-2-(2,6-cyfluoropendylthio)pyridine-N-oxide was dissolved in 50 tn of chloroform.
t, dissolved in metachloroperbenzoic acid (content 70%)
, a solution of ag dissolved in 30 ml of chloroform is 5 to 1
It was added dropwise over 10 minutes at 0°C, and after further stirring at 5-10°C for 2 hours, it was washed twice with an aqueous potassium carbonate solution, dried over magnesium sulfate, chloroform was distilled off, and the residue was diluted with benzene-hexane (1: 1) to give 5-chloro-2-(2°6-cyfluoropendylsulfinyl)pyridine-N-oxide (compound of the present invention (1) > 1.
5g was obtained. Yield 95%, melting point 156-157°C Proton NMR spectrum (shown as δ value in deuterated chloroform, based on tetramethylsilane) 8.8
(, m, L H), 7.6-6.7 (m, 5H)
, 4.8((1,2'H) Production Example 2 Compound of the present invention (2
) Production of 5-bromo-2-(2,6-cyfluoropendylthio)
2.5g of pyridine-N-oxide in 50ml of chloroform
A solution of 1°9f of metachloroperbenzoic acid (70% content) dissolved in 80ry+t of chloroform was added to
Drop it for 1 minute at 10℃, then add 2 drops at 5-10℃.
After stirring for 1 hour, it was washed twice with an aqueous potassium carbonate solution,
After drying over magnesium sulfate, chloroform was distilled off, and the residue was recrystallized from benzene to give 5-bromo-2-(2,
6-cyfluoropenzylsulfinyl)pyridine-N-
2.51 of oxide (invention compound (2)) was obtained.

Yield 95%, melting point 154-155°C Proton NMR spectrum C-weighted in loloform, expressed as δ value based on tetramethylsilane. ) 8. ．． 4
(Multiplet, IH), 7.7-6.7 (Multiplet, 5H), 4.8 (Quartet, 2H) The compounds of the present invention are shown in Table 1.

Table 1 When using the compound of the present invention with the general formula 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, powders, etc. The content of the compound of the invention as an active ingredient in the formulation is 0.5-90%, preferably 1-80%.

Examples of solid carriers include kaolin, bentonite,
Examples include talc, diatomaceous earth, gicrite, and synthetic hydrated silicon oxide. Examples of liquid carriers include aromatic hydrocarbons such as xylene and methylnaphthalene, cyclohexanone,
These include ketones such as isophorone, halogenated hydrocarbons such as chlorobenzene and dichloroethane, dimethylformamide, cellosolve, ethylene glycol, and water. Surfactants used for emulsification, dispersion, and expansion include polyoxyethylene alkyl ether, polyoxyethylene alkyl ether, polyoxyethylene styryl aryl ether, and polyoxyethylene fatty acid ester. , nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters, oxyethylene oxypropylene polymers, anionic surfactants such as alkyl sulfate salts, alkyl sulfonates, dialkyl sulfonates, and alkylaryl sulfonates. There are drugs etc.

As formulation aids, lignin sulfonate, alginate, polyvinyl alcohol, Cer+, +=+-S,
PAP (isopropyl acid phosphate), BHT (2,6-
Examples include di[-butyl-4-methylphenol).

Examples of formulations are shown below.

Formulation Example 1 80 parts of the compound of the present invention (1), 5 parts of polyoxyethylene alkylaryl ether, and 15 parts of synthetic hydrous silicon oxide
Thoroughly grind and mix the two parts to obtain a wettable powder.

Formulation Example 2 3 parts of the compound of the present invention (1), 10 parts of polyoxyethylene alkylaryl ether, 5 parts of alkylaryl sulfonate and 82 parts of isopolone are thoroughly mixed to obtain an emulsion.

Formulation Example 81% Granules 1 part of the compound of the present invention (2), 1 part of synthetic hydrous silicon oxide, 5 parts of sodium ligninsulfonate and 98 parts of kaolin were thoroughly ground and mixed, water was added and the mixture was thoroughly kneaded, followed by granulation. Dry to obtain granules.

Formulation Example 4 3 parts of the compound of the present invention (2), 0.0 parts of isopropyl acid phosphate.
5 parts of kaolin, 66.5 parts of kaolin, and 30 parts of talc are thoroughly ground and mixed to obtain a powder.

Formulation Example 5 20 parts of the compound of the present invention (1) was mixed with 60 parts of an aqueous solution containing 3% by weight of polyoxyethylene sorbitan monooleate, wet-pulverized until the particle size became 3μ or less, and a dispersion stabilizer was added to the mixture. A suspension is obtained by mixing 20 parts of an aqueous solution containing 3% by weight of sodium dithyalginate.

Emulsions, wettable powders, suspensions, etc. prepared in this way are
It is usually diluted with water and applied as is in granules, powders, etc., after treatment with foliage, soil treatment, or flooding. In addition, the compound of the present invention can be applied simultaneously with or without mixing with other herbicides in order to enhance its efficacy as a herbicide.
In some cases, synergistic effects can be expected.

Furthermore, it can be used in combination with insecticides, acaricides, nematicides, fungicides, plant growth regulators, fertilizers, soil conditioners, and the like.

When the compound of the present invention is used for either foliage treatment, soil treatment, or flooding treatment, the application rate can be varied over a fairly wide range, but usually the amount of active ingredient is 0.1 per are.
y~200g, preferably 0.2f~100g,
The application concentration is 0.0 for water diluents of emulsions, wettable powders, and suspensions.
It is 2% to 2%. These application amounts and concentrations can be increased or decreased depending on the type of preparation, application location, method, timing, crop, type of weed, degree of weed damage, weather conditions, etc. without being affected by the above range.

Next, test examples will be given to show that the compounds of the present invention are useful as active ingredients of herbicides. To determine chemical damage to crops and herbicidal efficacy against weeds, we measured the fresh weight of the stems and leaves of dead plants at the time of the survey, calculated the ratio (%) to that of the untreated area, and evaluated each from 0 to 5 according to the categories in Table 2. Shown in numerical value.

Table 2 Regarding the test compounds, the compounds of the present invention are shown by the compound numbers in Table 1, and the compounds used for comparison are shown by the compound symbols in Table 8.

Table 8 Test Example 1 Soil treatment test before germination in paddy fields A plastic port with an inner diameter of 8 crans and a height of 10 crns was filled with paddy soil, and seeds of Japanese millet, broad-leaved weeds (Azaena, Prunus japonicus), and firefly were sown, and then covered with soil. Water was poured until the water depth reached Bern. The sample was placed in a greenhouse for one day, and a predetermined amount of the emulsion prepared according to Formulation Example 2 was diluted with 5rrLt of water and dropped onto the water surface. The plants were placed in a greenhouse for an additional 20 days, and their herbicidal efficacy was investigated. The results are shown in Table 4.

Table 4 Test Example 2 Paddy foliage and soil treatment test A Wagner pot of 115,000 are was filled with paddy soil, and seeds of Japanese millet, bulrush, broad-leaved weeds (Azaena, Kikashigusa) and overwintering buds of Japanese grasshopper were mixed into the 3 cnt surface layer of the soil. . Furthermore, after adding water until the water level reached 4 (7), rice at the 3-leaf stage was transplanted. The weeds were grown in a greenhouse for 5 days, and when the weeds germinated, a predetermined amount of the emulsion prepared according to Formulation Example 2 was diluted with 10 rrLt of water and dropped onto the water surface.

Furthermore, after 20 days, the herbicidal efficacy and chemical damage to rice were investigated. The results are shown in Table 5.

Test Example 8 Upland pre-germination soil mixing treatment test diameter 10crn
Filled with field soil in a cylindrical plastic pot with a height of 10 crn, the seeds of barnyard millet, oat, mulva morning glory, and crocodile, as well as Cyperus esculentus
After sowing the tubers of P. lentus and covering the soil, dilute a prescribed amount of the emulsion prepared according to Formulation Example 2 with water and apply it to the soil surface with a small sprayer at a rate of 1°L per are. The soil surface layer up to 4 m was thoroughly mixed. After growing in a greenhouse for an additional 20 days, the herbicidal efficacy was investigated. The results are shown in Table 6.

Table 6 Test Example 4 Upland Soil Treatment Test Area: 8 x 28 cm, fl. It was covered with soil. The test compound was made into an emulsion according to Formulation Example 2, a predetermined amount of the emulsion was diluted with water, and the emulsion was applied to the soil surface at a rate of 10 liters per are 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 7.

Table 7 Table Test Example 5. Upland soil treatment test Pack field soil into a vat with an area of 88 x 28 cWl and a depth of 11 cr IK, and sow barley, barley, oat, black grass, and sycamore to a depth of 1 to 2 cm.
It was covered with soil to a thickness of . The test compound was made into an emulsion according to Formulation Example 2, and a quantitative amount of the emulsion was diluted with water and sprayed on the soil surface at a rate of 10 litres/are using a small sprayer. After treatment, the plants were grown in a greenhouse for 27 days, and their efficacy was investigated. The results are shown in Table 8) Table 8

Claims (3)

[Claims] (1) General formula [wherein, X represents a chlorine atom or a bromine atom]. ] A benzylsulfinylpyridine-N-oxide derivative represented by: (2) General formula [wherein, X represents a chlorine atom or a bromine atom]. ] A general formula characterized by oxidizing a benzylthiopyridine-N-oxide derivative represented by the formula [wherein, ] A method for producing a benzylsulfinylpyridine-N-oxide derivative. (3) General formula [wherein, X represents a chlorine atom or a bromine atom]. ] A herbicide characterized by containing a penzylsulfinylpyridine-N-oxide derivative represented by the following as an active ingredient.