JP2006225357A - 2-(2,6-dihalogenopyridin-4-ylmethyl)benzisothiazoline derivative and agricultural and horticultural plant disease controlling agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a 2-(2,6-dihalogenopyridin-4-ylmethyl)benzisothiazoline derivative or its salt capable of producing a remarkable controlling effect on agricultural and horticultural plant disease, and to provide an agricultural and horticultural plant disease controlling agent containing the derivative or its salt as an active ingredient. <P>SOLUTION: This 2-(2,6-dihalogenopyridin-4-ylmethyl)benzisothiazoline derivative is expressed by general formula [I] (Y is O or S; and R<SP>1</SP>and R<SP>2</SP>are each Cl or Br). The agricultural and horticultural plant disease controlling agent contains the benzoisothiazoline derivative or its salt as the active ingredient. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a 2- (2,6-dihalogenopyridin-4-ylmethyl) benzisothiazoline derivative or a salt thereof, and an agricultural and horticultural plant disease control agent comprising the derivative or a salt thereof as an active ingredient.

  In the cultivation of agricultural and horticultural crops, many control agents are used against crop diseases, but conventional control agents are used due to insufficient control efficacy or emergence of pathogenic bacteria with drug resistance. However, there are few things that are not necessarily satisfactory control agents from the viewpoint of causing phytotoxicity and pollution to plants, or toxic to human livestock and impact on the environment. Absent. Accordingly, there is a strong demand for the emergence of a control agent that can be safely used with few such drawbacks.

  Non-Patent Document 1 describes 2- (pyridylmethyl) -benzisothiazoline and the like similar to the 2- (2,6-dihalogenopyridin-4-ylmethyl) benzisothiazoline derivative which is the compound of the present invention. A compound in which the 2-position of the benzoisothiazoline ring is substituted with a 2,6-dihalogenopyridin-4-ylmethyl group is not described, and there is no description about a plant disease control agent for agriculture and horticulture.

  Patent Document 1 describes a compound in which the 2-position of the benzoisothiazoline ring is substituted with 2-pyridylethyl or 4-pyridylethyl group as a specific example, but 2,6-dihalogenopyridin-4-ylmethyl is described. Compounds substituted with groups are not described. Furthermore, in this patent document, the benzoisothiazoline derivative is described as a plant disease control agent, but in order to obtain a sufficient disease control effect, a high dose is required, so that it is not always satisfactory. I can't say that.

Journal of the Korean Chemical Society, 41, 666 (1997) JP-A-48-10228

  An object of the present invention is to solve the above-mentioned problems of conventional plant disease control agents, and to provide a plant disease control agent excellent in control effect, residual effect and the like.

  In order to achieve the above object, the present inventors have synthesized a large number of benzoisothiazoline derivatives that have not been known to have plant disease control activity so far, and have intensively studied their plant disease control activity and usefulness. As a result, the 2- (2,6-dihalogenopyridin-4-ylmethyl) benzisothiazoline derivative of the present invention (hereinafter referred to as the present compound) or a salt thereof is applied to a plant for a long period of time. The present inventors have found that a plant disease is controlled and a remarkable plant disease control effect is exhibited without causing any phytotoxicity to the plant, and the present invention has been completed.

  That is, the present invention relates to the following (1) or (2).

(1) General formula [I]

[Wherein Y represents an oxygen atom or a sulfur atom, and R ¹ and R ² each independently represent a chlorine atom or a bromine atom. ]
A 2- (2,6-dihalogenopyridin-4-ylmethyl) benzisothiazoline derivative or a salt thereof represented by the formula:

  (2) A plant disease control agent for agricultural and horticultural use comprising the 2- (2,6-dihalogenopyridin-4-ylmethyl) benzisothiazoline derivative or a salt thereof according to (1) as an active ingredient.

  Next, Table 1 shows specific examples of the compound of the present invention represented by the general formula [I]. However, the compound of the present invention is not limited to these compounds. The compound number is referred to in the following description.

Although the typical manufacturing method of this invention compound is illustrated below, the manufacturing method of this invention compound is not limited to these methods.
<Manufacturing method>

(In the formula, M represents an alkali metal such as a hydrogen atom or a sodium atom, R ¹ and R ² have the same meaning as described above, and X represents a halogen atom such as a chlorine atom or a bromine atom, or a methanesulfonyloxy group, A sulfonic acid ester such as a paratoluenesulfonyloxy group is shown.)

(Process 1)
The compound of the present invention represented by the general formula [Ia] is prepared by combining a saccharin or saccharin salt represented by the general formula [II] with a compound represented by the general formula [III] in the presence or absence of a base. It can be produced by reacting in the absence of a solvent. Hereinafter, for example, “a compound represented by the general formula [III]” and “compound [III]” are agreed.

  Compound [III] used in this step can be produced from 2,6-dihalogenoisonicotinic acid via an acid chloride or hydroxymethyl compound according to a conventional method. What is necessary is just to select the usage-amount of compound [III] from the range of 0.5-10 mol suitably with respect to 1 mol of compound [II], Preferably it is 0.8-1.2 mol.

  Examples of the base that can be used in this step include metal carbonates such as sodium carbonate and potassium carbonate, metal hydrogen carbonates such as sodium hydrogen carbonate and potassium hydrogen carbonate, carboxylates such as sodium acetate and potassium acetate, sodium methoxide, Metal alkoxides such as sodium ethoxide and potassium t-butoxide, metal hydroxides such as sodium hydroxide, potassium hydroxide and calcium hydroxide, metal hydrides such as sodium hydride, potassium hydride and calcium hydride, triethylamine, N, N-diisopropylethylamine, pyridine, 1,8-diazabicyclo [5.4.0. ] Organic bases such as -7-undecene (DBU).

  What is necessary is just to select the usage-amount of a base suitably from the range of 0-10 mol with respect to 1 mol of compound [II], Preferably it is 0-1.2 mol.

  The solvent that can be used in this reaction is not particularly limited as long as it does not inhibit the progress of this reaction, and examples thereof include ethers such as diethyl ether, tetrahydrofuran, dioxane, monoglyme, diglyme, dichloromethane, chloroform, carbon tetrachloride, dichloroethane, and the like. Halogenated hydrocarbons, aromatic hydrocarbons such as benzene, chlorobenzene, nitrobenzene, toluene, amides such as N, N-dimethylformamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone And the like, sulfur compounds such as dimethyl sulfoxide, nitriles such as acetonitrile, and the like, and a mixed solvent thereof can also be used.

  What is necessary is just to select reaction temperature from the range of the boiling point range of the inert solvent used from -20 degreeC, It is good to carry out in the range of 0 to 100 degreeC preferably.

  The reaction time varies depending on the reaction temperature, reaction substrate, reaction amount and the like, but is usually 30 minutes to 48 hours.

  The compound of the present invention represented by the general formula [Ia], which is the target of the reaction, is collected from the reaction system by a conventional method after completion of the reaction. The obtained target product can be purified by operations such as column chromatography and recrystallization as necessary.

(Process 2)
The compound of the present invention represented by the general formula [Ib] is prepared by a generally known method [for example, Journal of Organic Chemistry, Vol. 16, p. 1582 (1951). In accordance with the method described in Indian Journal of Chemistry Section B, Vol. 27, page 109 (1988)], compound [Ia] and a thiocarbonylating agent are It can manufacture by making it react in a solvent or under non-solvent.

  What is necessary is just to select the usage-amount of the thiocarbonylating agent used at this process suitably from the range of 0.5-10 mol with respect to 1 mol of compound [Ia], Preferably it is 1.0-2.0 mol. .

  Examples of the thiocarbonylating agent that can be used in this step include phosphorus pentasulfide and Lawesson's reagent (2,4-bis (4-methoxyphenyl) -1,3-dithia-2,4-diphosphetane-2,4-disulfide). Etc.

  The solvent that can be used in this reaction is not particularly limited as long as it does not inhibit the progress of this reaction, and examples thereof include ethers such as diethyl ether, tetrahydrofuran, dioxane, monoglyme, diglyme, dichloromethane, chloroform, carbon tetrachloride, dichloroethane, and the like. Halogenated hydrocarbons, aromatic hydrocarbons such as benzene, chlorobenzene, nitrobenzene, toluene, xylene, amides such as N, N-dimethylformamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazo Ureas such as lizinone, sulfur compounds such as dimethyl sulfoxide, nitriles such as acetonitrile, pyridine and the like can be used, and a mixed solvent thereof can also be used.

  What is necessary is just to select reaction temperature from the range of the boiling point range of the inert solvent used from -20 degreeC, Preferably it is good to carry out in 0-150 degreeC.

  The reaction time varies depending on the reaction temperature, reaction substrate, reaction amount and the like, but is generally 30 minutes to 48 hours.

  The agricultural and horticultural plant disease control agent of the present invention comprises a 2- (2,6-dihalogenopyridin-4-ylmethyl) benzisothiazoline derivative represented by the general formula [I] or a salt thereof as an active ingredient.

  When the compound of the present invention is used as an agricultural / horticultural plant disease control agent, it may be used alone, but the active ingredient can be used in an appropriate dosage form depending on the purpose.

  Usually, the active ingredient is diluted with an inert liquid or solid carrier, and if necessary, a surfactant or the like is added thereto, and it can be used in the form of a powder, wettable powder, emulsion, granule or the like. The blending ratio of the active ingredient is appropriately selected as necessary, but 0.1 to 50% (weight) when used as a powder and granule, and 5 to 80% (weight) when used as an emulsion and wettable powder. Is appropriate.

  Examples of carriers used for formulation include talc, bentonite, clay, kaolin, diatomaceous earth, white carbon, vermiculite, calcium carbonate, slaked lime, silica sand, ammonium sulfate, urea and other solid carriers, isopropyl alcohol, xylene, cyclohexane, methylnaphthalene, etc. Liquid carriers and the like.

  Surfactants and dispersants include, for example, alkylbenzene sulfonic acid metal salts, dinaphthylmethane disulfonic acid metal salts, alcohol sulfate esters, alkylaryl sulfonates, lignin sulfonates, polyoxyethylene glycol ethers, polyoxyethylene alkyls. Examples thereof include aryl ethers and polyoxyethylene sorbitan monoalkylates.

  Examples of the auxiliary agent include carboxymethyl cellulose, polyethylene glycol, gum arabic and the like.

  Furthermore, the plant disease control agent for agricultural and horticultural use of the present invention includes other known active compounds as necessary in addition to the compound of the present invention which is an active ingredient in the above various preparation forms, for example, insecticides, acaricides, You may mix with an insect growth regulator, a nematicide, a fungicide, a plant disease control agent, a herbicide, a plant growth regulator, a fertilizer, a soil conditioner, etc.

  The plant disease control agent for agricultural and horticultural use according to the present invention can be used by spraying these leaves as they are or by diluting them, spraying seeds, applying seeds, applying soil, applying water or raising seedling boxes. These application rates vary depending on the type of compound used, target disease, occurrence tendency, degree of damage, environmental conditions, dosage form used, and the like.

  For example, when using it as it is like a powder agent and a granule, it is good to select suitably from the range of 0.1g-5kg per 10 are, preferably 1g-1kg with an active ingredient.

  Further, when used in a liquid form such as an emulsion and a wettable powder, it is suitably selected from the range of 0.1 ppm to 10,000 ppm, preferably 10 to 3,000 ppm.

  Furthermore, when used by raising a seedling box, it is possible to provide a long-term effect by preparing a formulation with controlled dissolution of the compound.

  The plant disease control agent for agricultural and horticultural use of the present invention can control plant diseases caused by filamentous fungi, bacteria and viruses by the above-mentioned application form.

Next, specific diseases are given as non-limiting examples.
Cucumber downy mildew (Pseudoperonospora cubensis), apple black spot disease (Venturia inaequalis), cucumber powdery mildew (Sphaerotheca cucurbitae), wheat powdery mildew (Erysiphe graminis), wheat blight fungus (Septoria nodorum), rice blast ore yz (Pyricularia) ), Cucumber gray mold (Botrytis cinerea), rice rot (Rhizoctonia solani), wheat rust (Puccinia recondita), cucumber spot bacterial disease (Pseudomonas syringe), rice white leaf blight (Xanthomonas oryzae), rice blast Disease (Burkholderia glumae), rice seedling bacterial disease (Burkholderia plantarii), rice brown disease (Acidovorax avenae), inner bud browning disease (Erwinia ananas)

  The plant disease control agent for agricultural and horticultural use according to the present invention also has a feature of having a high control effect on rice blast disease and the like without causing phytotoxicity to crops. Useful as an agent.

  Hereinafter, the production method, formulation method and use of the derivative of the general formula [I] used in the agricultural and horticultural plant disease control agent of the present invention will be described in detail in the following examples, but the present invention is not limited to these examples. Is not to be done. In the following description, “%” represents a weight percentage.

Preparation of 2- (2,6-dichloropyridin-4-ylmethyl) -1,2-benzisothiazolin-3-one 1,1-dioxide (Compound No. 1)
1.49 g (8.2 mmol) of saccharin and 1.64 g (6.8 mmol) of 4-bromomethyl-2,6-dichloropyridine are dissolved in 20 ml of tetrahydrofuran, and 1.14 g (8.6 mmol) of N, N-diisopropylethylamine is dissolved. And stirred at room temperature for 15 hours. After completion of the reaction, ethyl acetate was added, washed with water, dried over anhydrous magnesium sulfate and concentrated. The obtained crystals were washed with ethyl acetate, and colorless crystals (melting point: 176-178 ° C.) 2- (2,6-dichloropyridin-4-ylmethyl) -1,2-benzisothiazolin-3-one-1,1 1.62 g (yield 69%) of the dioxide was obtained.
¹ H-NMR (CDCl ₃ ) δ: 4.85 (2H, s), 7.36 (2H, s), 7.87-8.00 (3H, m), 8.11 (1H, d, 6.8Hz) ppm

Preparation of 2- (2,6-dichloropyridin-4-ylmethyl) -1,2-benzisothiazoline-3-thione 1,1-dioxide (Compound No. 2)
2- (2,6-dichloropyridin-4-ylmethyl) -1,2-benzisothiazolin-3-one 1,1-dioxide 0.40 g (1.17 mmol), phosphorus pentasulfide 0.78 g (3.5 mmol) And 10 ml of chlorobenzene were heated and stirred at 110 ° C. for 3 hours. After completion of the reaction, ethyl acetate was added, insoluble matter was filtered off, and the solvent was concentrated under reduced pressure. The residue was purified by silica gel column chromatography, and 2- (2,6-dichloropyridin-4-ylmethyl) -1,2-benzisothiazoline-3-thione-1,1- in the form of yellow crystals (melting point 187-188 ° C.) 0.25 g (yield 60%) of the dioxide was obtained.
¹ H-NMR (CDCl ₃ ) δ: 5.18 (2H, s), 7.34 (2H, s), 7.83-7.93 (3H, m), 8.29 (1H, d, 7.8Hz) ppm

Preparation of 2- (2,6-dibromopyridin-4-ylmethyl) -1,2-benzisothiazolin-3-one 1,1-dioxide (Compound No. 3)
In the same manner as in Example 1, 2- (2,6-dibromopyridin-4-ylmethyl) -1,2-benzisothiazolin-3-one 1,1-dioxide of colorless crystals (melting point: 172-174 ° C.) ( Yield 51%).
¹ H-NMR (CDCl ₃ ) δ: 4.81 (2H, s), 7.55 (2H, s), 7.83-8.00 (3H, m), 8.11 (1H, d, 7.6Hz) ppm

Reference example 1
Preparation of (2,6-dichloropyridin-4-yl) methanol 18.0 g (475 mmol) of sodium borohydride was suspended in 250 ml of water and 50.0 g (238 mmol) of 2,6-dichloroisonicotinic acid chloride in tetrahydrofuran. A 50 ml solution was added dropwise at 5-10 ° C. After completion of dropping, the mixture was stirred at 10 ° C. for 10 minutes, and 500 ml of ethyl acetate was added. The mixture was acidified with 20% hydrochloric acid, and the organic layer was washed with water, dried and concentrated. The precipitated solid was washed with isopropyl ether to obtain 40.2 g (yield 95%) of (2,6-dichloropyridin-4-yl) methanol as a colorless powder (melting point 130-131 ° C.).
¹ H-NMR data (CDCl ₃ / TMS δ (ppm)): 4.65 (2H, d, J = 5.8Hz), 4.96 (1H, t, J = 5.8Hz), 7.29 (2H, s)

Reference example 2
Preparation of 4-bromomethyl-2,6-dichloropyridine 30.0 g (169 mmol) of (2,6-dichloropyridin-4-yl) methanol was dissolved in 1 L of ether, and 50.2 g (185 mmol) of phosphorus tribromide was added. And stirred at room temperature for 15 hours. After completion of the reaction, water was added and the mixture was stirred for 1 hour. The organic layer was washed with water, dried and concentrated to dryness, and 28.4 g of 4-bromomethyl-2,6-dichloropyridine as colorless crystals (melting point: 38-40 ° C.) 70%).
¹ H-NMR data (CDCl ₃ / TMS δ (ppm)): 4.33 (2H, s), 7.29 (2H, s)

Note that this compound is used in the manufacturing method of the present invention compounds of the general formula [III] a compound represented by, R ¹ and R ² is a chlorine atom, X is a compound of a bromine atom.

Powder A compound of Compound No. 1 2%, diatomaceous earth 5% and clay 93% were mixed and ground uniformly to obtain a powder. Moreover, it can replace with the compound number 1 and can obtain a dust similarly using each compound of Table 1.

Wettable powder 50% of Compound No. 2, 45% diatomaceous earth, 2% sodium dinaphthylmethane disulfonate and 3% sodium ligninsulfonate were uniformly mixed and ground to obtain a wettable powder. Further, a wettable powder can be similarly obtained using each of the compounds shown in Table 1 instead of Compound No. 2.

Emulsion 30% of compound No. 3, 20% cyclohexanone, 11% polyoxyethylene alkylaryl ether, 4% calcium alkylbenzenesulfonate and 35% methylnaphthalene were uniformly dissolved to prepare an emulsion. Further, an emulsion can be obtained in the same manner using each of the compounds shown in Table 1 instead of Compound No. 3.

Granules Compound 24 of Compound No. 1, 2% sodium salt of lauryl alcohol sulfate, 5% sodium lignin sulfonate, 2% carboxymethyl cellulose and 67% clay are mixed and ground uniformly. The mixture was kneaded by adding an amount equivalent to 20% of water, processed into 14-32 mesh granules using an extrusion granulator, and dried to give granules. Moreover, it can replace with the compound number 1 and can obtain a granule similarly using each compound of Table 1.

  Next, the effects of the agricultural / horticultural plant disease control agent of the present invention will be specifically described with reference to test examples.

Test Example 1 Rice Blast Disease Water Surface Application Test Three 1.5-stem paddy rice seedlings (variety: Aichi Asahi) seedlings were transplanted in four places at 9 locations in a white ceramic pot of 9 cm in diameter and grown in a greenhouse. At the 2.5 leaf stage, the wettable powder prepared according to Example 5 was applied to the pot with water so that the active ingredient concentration was 100 g per 10 ares. Ten days after the treatment, a conidial spore suspension of rice blast fungus (Pyricularia oryzae) was spray-inoculated and immediately placed in a humid chamber at 25 ° C. for 24 hours. Then, it moved to the greenhouse and investigated the number of lesions of the highest leaf at the time of inoculation 5 days after the inoculation. The control value was determined by the following formula, and the results are shown in Table 2.

  Moreover, using each of the comparative compounds shown below, a wettable powder was prepared according to Example 5 and the control value was determined in the same manner as in this test example. The results are shown in Table 2.

Claims (2)

Formula [I]

[Wherein Y represents an oxygen atom or a sulfur atom, and R ¹ and R ² each independently represent a chlorine atom or a bromine atom. ]
A 2- (2,6-dihalogenopyridin-4-ylmethyl) benzisothiazoline derivative or a salt thereof represented by the formula: A plant disease control agent for agricultural and horticultural use comprising the 2- (2,6-dihalogenopyridin-4-ylmethyl) benzisothiazoline derivative or a salt thereof according to claim 1 as an active ingredient.