KR900003396B1 - Dihalogen-substituted thiocyano pyrimidine derivatives,and agricultural and horticultural fungicidal compositions - Google Patents

Abstract

Dihalogenothiocyanopyrimidine derivs. of formual (I) are prepd. by reacting trihalogenopyrimidine derviv. with thiocyanate in an org. acid i.e. formic acid, acetic acid, propionic acid at 20-60 deg. C. In (I), X=Y=halogen. (I) are useful as an agricultural and horticultural fungicide.

Description

Dihalogen-substituted thiocyanopyrimidine derivatives, preparation method thereof and agrohorticultural fungicide

The present invention relates to a dihalogenothiocyanopyrimidine derivative represented by the following general formula (I), a preparation method thereof, and an agricultural and horticultural fungicide containing the derivative thereof as an active ingredient.

(X and Y represent a halogen atom.)

Conventionally, many studies have been conducted on pyrimidine derivatives, numerous compounds have been synthesized, and many compounds having characteristic physiological activities have been found in the agricultural medicine field. However, the practical use of a compound in which a thiocyano group is introduced into a pyrimidine nucleus is not yet known.

Very few are known about the synthesis examples of the pyrimidine derivatives having thiocyano groups, and little is known about their physiological activities.

Only in the pharmacy journal of Japan, 83,1086 (1963), the thiocyanopyrimidine derivatives and their in vitro are described as antimicrobial activity. This document describes 15 thiocanopyrimidine derivatives and their antimicrobial activity, with the highest active compounds being 2- (or 4) -chloro-6-methyl-4 (or 2) -thiocyano It is described that the antimicrobial activity of the thiocyanopyrimidine derivative which is pyrimidine and has a substituent at position 5 generally tends to be lower. Little is known about thiocyanopyrimidine derivatives having a halogen atom at position 5.

The present inventors have already filed a patent on the invention for thiocyanopyrimidine derivatives (Japanese Patent Publication No. 193,970 / 1985). More specifically, the present invention relates to 2,4-dihalogeno-5-alkylthio-6-thiocyanopyrimidine derivatives useful as agricultural and horticultural fungicides and have quite good effects. However, the sustainability of the effect is insufficient. In addition, the effect of plant pathogens on the horticultural production is extremely large, and in recent years, various kinds of fungicides are used against various plant diseases, but a certain amount of stable production is possible, but there are still many problems to be improved.

For example, in order to control late blight caused by phycomycetes and various diseases of various crops, existing fungicides must use a very large amount of drugs, and their effects depend on the time of use, weather, etc. Is difficult. In the case of gray fungal diseases (Botrytis Cinerea) and Sclerotinia Scleroiorum of various crops, the emergence of drug resistance is expected to have almost no control effect other than benzimidazole or dicarboxylic acid imide fungicides.

The present inventors conducted extensive research on pyrimidine derivatives focusing on the pyrimidine nucleus, which is thought to play a special role in interaction with a living body, in order to solve the above-mentioned problems. Although there are literatures that the antimicrobial activity of cyanopyrimidine derivatives is lowered, 2,5-dihalogeno-4-thiocyanopyrimidines having a halogen atom at the 5th position are caused by late blight and phytopathogens. It has a very strong control effect against crop diseases, and the halogen atom at 5th position strengthens the effect, and also has 4-thiocy having a methylthio group at 5th position as described in Japanese Patent Laid-Open No. 193,970 / 1985. The present invention was completed by discovering the long-term sustained action as compared to the anpyrimidine derivative.

Another object of the present invention is to provide a novel thiocyanpyrimidine derivative.

It is another object of the present invention to provide a method for preparing the thiocyanopyrimidine derivative described above.

Another object of the present invention is to control the composition according to the present invention to a wide range of plant diseases, including late blight, germ disease, gray mold disease, which is a major factor of economic losses, It is to provide a new agricultural and horticultural fungicide including a new treatment device because the effect of controlling against pathogens resistant to the fungicide is effective and their activity also lasts for a long time.

The above-mentioned objects of the present invention are dihalogenothiocyanopyrimidine derivatives of the following general stone (I) as novel compounds: trihalogenopyrimidine derivatives of the following general formula (II) and thiocia of the general formula (III) A process for preparing a dihalogenothiocyano pyrimidine derivative of the general formula (I) characterized by reacting a nate: and containing dihalogenothiocyanopyrimidine derivatives of a single type (I) as an active ingredient. By providing agrohorticultural fungicides.

In the above formulas, X and Y are halogen atoms: M is an alkali metal or ammonium.

Dihalogenothiocyanopyrimidine derivatives of the general formula (I) related to the present invention are exemplified by 2,5-difluoro-4-thiocyanopyrimidine and 5-chloro-2-fluoro-4. -Thiocyanopyrimidine, 5-bromo-2-fluoro-4-thiocyanopyrimidine, 2-fluoro-5-iodo-4-thiocyanopyrimidine, 2-chloro-5-fluoro Ro-4-thiocyanopyrimidine, 2,5-dichloro-4-thiocyanopyrimidine, 5-bromo-2-chloro-4-thiocyanopyrimidine, 2-chloro-5-iodo- 4-thiocyanopyrimidine, 2-bromo-5-fluoro-4-thiocyanopyrimidine, 2-bromo-5-chloro-4-thiocyanopyrimidine, 2,5-dibromo 4-thiocyanopyrimidine, 2-bromo-5-iodo-4-thiocyanopyrimidine, 5-fluoro-2-iodo-4-thiocyanopyrimidine, 5-chloro-2 Open urethodo-4-thiocyanopyrimidine, 5-bromo-2-iodo-4-thiocyanopyrimidine and 2,5-diiodo-4-thiocyanopyrimidine Can.

Dihalogenothiocyanopyrimidine derivatives of general formula (I) according to the present invention are novel compounds and control effects against a wide range of plant diseases including late blight, fungal disease, powdery mildew, gray mold disease and similar diseases of various crops. It is useful because it is excellent. In addition, the derivatives according to the invention are very stable to crops, for example, no harm to tomato, cucumber, potato, etc., furthermore, the toxicity to animals is also low.

Hereinafter, a method for preparing the dihalogenothiaminopyrimidine derivatives of the general formula (I) according to the present invention will be described in detail. Compounds according to the present invention can be prepared by the following reaction process formula:

In the above formulas, X and Y are halogen atoms: M is an alkali metal or ammonium.

Among the various trihalogeno compounds of general formula (II) useful as starting materials, the dichloro compounds in which X in the general formula (II) represents a chlorine atom are treated with phosphorus oxychloride of 5-halogenouracil in the presence of dimethylaniline. The dibromo compounds in which X represents a bromine atom in general formula (II) can be obtained by treating 5-halogenouracil with phosphorus oxybromide in the presence of dimethylaniline. Diiodo compounds in which X is iodo in general formula (II) can be obtained by treating dichloro compounds with concentrated iodide acid, and difluoro compounds in formula (II) are dichloro compounds. It can be obtained by treating with carbofluoride fluoride.

The manufacturing method of the 2, 5- dihalogeno-4- thio cyano pyrimidines of general formula (I) which concerns on this invention is demonstrated in detail. The present invention is a method characterized by reacting trihalogeno compound (II) and thiocyanate (III) in a solvent. Useful thiocyanates include potassium thiocyanate, sodium thiocyanate, ammonium thiocyanate, and the like, and any of these compounds can be used to obtain good results. As the solvent, a solvent having the greatest effect on the reaction is used in the present invention.

When the reaction is carried out in alcohols such as methanol and ethanol, the reaction rate is slow even under reflux conditions. In addition, the yield is extremely low because it is produced in the dendritic material as a by-product. This reaction is carried out in an aprotic solvent such as acetone, dimethyl sulfoxide, N, N-dimethylformamide, l, 3-dimethyl-2-imidazolinone, and the like. The desired product (I) is obtained only in low yield because by-products with nogi or isothiocyanate are by-products. However, the inventors have found that the reaction can be significantly improved by carrying out the reaction in an organic acid such as formic acid, acetic acid, propionic acid, etc., as opposed to the cases using the solvents described above. Reactivity is reduced in the order of formic acid, acetic acid and propionic acid, the effect of formic acid is particularly pronounced. For example, when the reaction is carried out in acetic acid at 50 ℃ takes 5 hours or more to terminate the reaction, when the reaction is carried out in formic acid of the same temperature is less than 1 hour to complete the reaction. The reaction temperature may vary from 10 ° C. to outside the boiling point of the solvent, but it is preferred to employ a reaction temperature of 20 to 60 ° C. to minimize the formation of by-products and to idealize the reaction time.

Therefore, in view of the selectivity of the reaction and the ease of reaction progress, formic acid in the reaction of the present invention can be said to have excellent properties significantly different from other organic solvents, especially other organic solvents having relatively good characteristics.

After the reaction is completed, the reaction mixture is discharged into a large amount of water. If the precipitate is a solid, it is filtered and dried. In this way, off-target crude crystals can be obtained with a yield of 90% or more. In the case where the precipitate is an oil phase, the resultant is extracted in an inert solvent such as ethyl acetate, benzene, toluene, washed with water, and then dehydrated to obtain an oily product of a crude product. Since the crude oil itself has a relatively high purity, it can be used as a fungicide without further purification. However, if necessary, it is possible to recrystallize in any of commonly used solvents such as isopropyl ether, chloroform, carbon tetrachloride, ethyl acetate, ethanol and methanol, or to obtain a purified product by column chromatography.

The compounds according to the invention show a strong control against a wide range of plant diseases, including late blight, mildew, powdery mildew, gray mold and similar diseases of various crops.

Compounds according to the present invention can be used by various methods such as seed disinfection, foliage spraying, and soil treatment, and can exhibit sufficient effects by using any method commonly used in the art.

The amount and concentration of the compound according to the present invention vary depending on the target crop, the target disease, the extent of the disease, the formulation of the compound, the method of use, and various environmental conditions. 5 to 100 g is preferred. The concentration of the suspension is suitably in the range of 100 to 1000 ppm, preferably 200 to 500 ppm.

Agrohorticultural fungicides according to the present invention may be mixed with other fungicides, insecticides, herbicides, plant growth regulators, pesticides, soil conditioners and / or fertilizers, as well as mixing aids thereof.

The compounds according to the invention can be used as such, but are preferably used in the form of a composition mixed with a carrier containing a solid or liquid diluent. As used herein, the term carrier means a synthetic or natural inorganic or organic material that can be formulated to help reach the active ingredient at the site to be treated or to facilitate storage, transport and handling of the active ingredient compound. do.

Suitable solid carriers include inorganic materials such as clays such as montmorillonite and kaolinite, diatomaceous earth, clay, talc, burmeculite, gypsum, calcium carbonate, silica gel and ammonium sulfate: vegetable organic substances such as soy flour, sawdust and wheat flour: Elements can be enumerated.

Suitable liquid carriers include aromatic hydrocarbons such as toluene, xylene and cumene, paraffinic hydrocarbons such as kerosene and mineral oil: halogenated hydrocarbons such as carbon tetrachloride, chloroform and dichloroethane: ketones such as acetone and methyl ethyl ketone: dioxane and tetra Ethers such as hydrofuran; alcohols such as methanol, propanol and ethylene glycol; dimethylformamide: dimethyl sulfoxide: water and the like.

In order to increase the potency of the compounds according to the present invention, the following auxiliaries may be used alone or in combination according to the purpose in consideration of the kind, application state, etc. of the preparation.

Water-soluble bases such as lignin sulfonic acid salts for the purpose of emulsification, dispersion, electrodeposition, infiltration, bonding, stabilization, etc. Anionic surfactants such as alkylbenzene sulfonates: alkyl sulfate esters, polyoxyalkylene alkyl ethers, polyoxyalkyl Ylene alkylaryl ethers, polyoxyalkylene alkylamines, polyoxyalkylene alkylamides, polyoxyalkylene alkylthio ethers, polyoxyalkylene fatty acid ethers, glycerol fatty acid esters, sorbitan fatty acid esters, Nonionic surfactants, such as polyoxyalkylene sorbitan fatty acid ester and polyoxypropylene-polyoxyethylene block copolymer, etc. Lubricants, such as calcium stearate and a wax, Stabilizers, such as isopropyl hydrogen phosphate: And methylcellulose And other auxiliaries such as carboxymethyl cellulose, casein and gum arabic.

However, useful adjuvants are not limited to those described above.

In the composition containing the compound according to the present invention, the content of the active ingredient is usually 0.5 to 20% by weight in the case of powder, 5 to 30% by weight in the emulsion stock solution, and 10 to 90% by weight in the case of a hydrating agent. In the case of granulation, it is 0.1 to 20% by weight, and in the case of a flow agent, it is 10 to 90% by weight.

Synthesis examples are listed below to more specifically describe the process for producing compounds according to the present invention.

Synthesis Example 1

Synthesis of 2-chloro-5-iodo-4-thiocyanopyrimidine (Compound No. 1):

Into a 300 ml four-necked flask equipped with a thermometer and a stirrer, 35.0 g of 2,4-dichloro-5-iodopyrimidine, 15.0 g of potassium thiocyanate and 150 ml of formic acid were added. The reaction mixture is stirred at room temperature (20 ° C.) for 3 hours. After the reaction is completed, the reaction mixture is discharged into a large amount of water, and the precipitates are filtered off and dried to obtain crude crystals.

These crystals are then recrystallized in toluene to give 28.5 g (yield 75.4%) of 2-chloro-5-iodo-4-thiocyanopyrimidine having a melting point of 185 to 186.5 占 폚.

NMR (CC ₁ 4): δ = 8.34 ppm (s)

IR (KBr): 2190 ^-1 (-SCN).

Synthesis Example 2

2-Chloro-5-fluoro-4-thiocyanopyrimidine (Synthesis of Compound No.2:

10.0 g of 2,4-dichloro-5-fluoropyrimidine and 5.8 g of potassium thiocyanate are reacted for 5 hours in 50 ml of formic acid at room temperature (20 ° C.) for 5 hours as in Synthesis Example 1. Next, the reaction mixture is carried out as in Synthesis Example 1 to obtain 2-chloro-5-fluoro-4-thiocyanopyrimidine (yield, 68.0%). Melting point, 103-104 캜

NMR (DMSO-d ₆ ): δ = 8.85 ppm (s).

IR (KBr): 2180 cm ^-1 (-SCN).

Synthesis Example 3

Synthesis of 2,5-dichloro-4-thiocyanopyrimidine (Compound NO.3):

17 g of 2,4,6-trichloropyrimidine and 9.7 g of potassium thiocyanate were reacted in 100 ml of formic acid at room temperature (20 ° C.) for 4 hours as in Synthesis Example 1. Next, the reaction mixture was treated as in Synthesis Example 1 to obtain 2,5-dichloro-4-thiocyanopyrimidine (yield, 65.0%) melting point, l60.5 to 161.5 ° C.

NMR (DMSO-d ₆ ): δ = 8.85 ppm (s).

IR (KBr): 2160 cm ^-1 (-SCN).

Synthesis Example 4

Synthesis of 5-bromo-2-chloro-4-thiocyanopyrimidine (Compound No. 4):

23.0 g of 5-bromo-2,4-dichloropyrimidine and 10.0 g of potassium thiocyanate were reacted in 100 ml of formic acid at room temperature (20 ° C.) for 4 hours in a similar manner as in Synthesis Example 1. Next, the reaction mixture was treated as in Synthesis Example 1 to obtain 5-bromo-2-chloro-4-thiocyanopyrimidine (yield 80.0%). Melting point, 166.5-170 ° C.

NMR (DMSO-d ₆ ): δ = 8.85 ppm (s).

IR (KBr): 2150 cm ^-1 (-SCN).

Synthesis Example 5

Synthesis of 5-chloro-2-iodo-4-thiocyanopyrimidine (Compound No. 5):

18.4 g of 5-chloro-2,4-diiodopyrimidine and 6.0 g of carium thiocyanate are reacted in 100 ml of formic acid at 60 ° C. for 1 hour as in Synthesis Example 1.

The reaction mixture was then treated as in Synthesis Example 1 to yield 5-chloro-2-iodo-4-thiocyanopyrimidine (yield, 62.5%). Melting point, 183-186 캜

IR (KBr): 2170 cm ^-1 (-SCN).

5-chloro-2,4-diiodopyrimidine used as starting material can be easily obtained by adding 2,4,5-trichloropyrimidine to hydroiodic acid and stirring at room temperature for 4 hours.

Synthesis Example 6

Synthesis of 5-bromo-2-iodo-4-thiocyanopyrimidine (Compound No. 6):

4.11 g of 5-bromo-2,4-diiodopyrimidine and 1.17 g of potassium thiocyanate are reacted for 5 hours in 30 ml of formic acid at room temperature (20 ° C.) as in Synthesis Example 1. The reaction mixture was then treated as in Synthesis Example 1 to yield 5-bromo-2-iodo-4-thiocyanopyrimidine (yield, 82.4%). Melting point, 199-202 캜

IR (KBr): 2180 cm ^-l (-SCN).

Synthesis Example 7

Synthesis of 2,5-diiodo-4-thiocyanopyrimidine (Compound No. 7):

19.0 g of 2,4,5-triiodopyrimidine and 5.0 g of potassium thiocyanate are reacted in 150 ml of formic acid at room temperature (20 ° C.) for 3 hours as in Synthesis Example 1. Next, the reaction mixture was treated as in Synthesis Example 1 to obtain 2,5-dioodo-4-thiocyanopyrimidine (yield, 84.7%). Melting point, 183-185 ° C

IR (KBr): 2160 cm ^-1 (-SCN).

Next, the preparation method of the agricultural and horticultural fungicides according to the present invention will be described in more detail with reference to the formulation examples. An active ingredient compound is represented by the compound number in the synthesis example mentioned above. All "parts" represent a "weight part."

Preparation Example 1 (Hydrating Agent)

30 parts of compound No. 1, 44 parts of diatomaceous earth, 20 parts of clay, 1 part of sodium lignin sulfonate, and 2 parts of sodium alkylbenzenesulfonate are uniformly ground and mixed to obtain 100 parts of a hydrate.

Preparation Example 2 (granulation)

7 parts of compound No. 1, 1 part of polyethylene glycol nonylphenyl ether, 3 parts of polyvinyl alcohol and 89 parts of clay are uniformly mixed, and after granulation, it is rolled to obtain 100 parts of granules.

Preparation Example 3 (Hydrating Agent)

50 parts of compound No. 1, talc 40 parts, sodium lauryl phosphate 5 parts and alkyl naphthalene sulfonic acid sodium 5 parts are mixed and 100 parts of hydrates are obtained.

Preparation Example 4 (Hydrating Agent)

Compound no. 2 50 parts, 10 parts of sodium lignin sulfonate, 5 parts of sodium alkyl natylene sulfonate, 10 parts of white carbon and 25 parts of diatomaceous earth are mixed and ground to obtain 100 parts of a hydrate.

Preparation Example 5 Fluidizing Agent

40 parts of compound No. 1, 3 parts of carboxymethyl cellulose, 2 parts of lignin sulfonic acid tartrum, 1 part of sodium dioctylsulfosuccinate salt and 54 parts of water are wet-pulverized with a sand grinder to obtain 100 parts of a fluidizing agent.

Next, the effect of the compound of this invention as an agricultural and horticultural fungicide is demonstrated by the following test example. In these test examples, the following compounds are used as controls.

A: 2-chloro-6-methyl-4-thiocyanopyrimidine.

B: tetrachloroisophthalonitrile (Daconil).

C: 1- (butylcarbamoyl) -2-benzimidazolylcarbamic acid methyl ester (Benlate). 2,4-dichloro-5-methylthio-6-thiocyanopyrimidine.

Control compound A is the base compound of the aforementioned Japanese Pharmacy Journal, 83, 1086 (1963), B is a commercially available disinfectant such as potato blight, cucumber, and mildew disease, and C is a commercially available disinfectant such as gray mold disease. Is a bactericide, and D is a compound described in Japanese Patent Laid-Open No. 193,970 / 1985.

[Test Example 1]

Potato Blight Control Test (by Phyto phthora infestans).

Potato plants (variety: baron) are grown in a pot until they are about 25 cm tall in a greenhouse. Next, a hydrating agent is prepared by the method of Formulation Example 3 described above and diluted with water to a predetermined concentration. A suspension of each of the disclosed compounds of the desired concentration is sprayed at a rate of 50 ml per three pots using a spray gun (1.0 kg / cm ² ) and air dried.The pots are kept in a greenhouse for five days and then Strainer suspensions are prepared from potato plague strains cultured on potato slices for 7 days and then sprayed onto potato plants treated with the respective compounds.

The contacting plants are kept at a temperature of 17-19 ° C. and a relative humidity of 95% or more for 6 days, and then the degree of formation of lesions is examined.

The area ratio of lesions is visually evaluated for each leaf, and the degree of morbidity index is determined by the following criteria.

Lee Byeong-Do Index 0: Disease area ratio 0%

Lee Byung-Do Index 1: lesion area ratio 1-5% Lee Byung-Do Index 2: lesion area ratio 6-25%

Byeongdo Lee Index 3: 25-50% lesion area ratio

Lee Byeong-do index 4: 51% ol phase lesion area ratio.

Using the obtained disease degree index, the disease degree of each test group is computed by the following formula.

n0: leaf number of Lee Byeong-do index 0

n1: leaf number of Lee Byeong-do index 1

n2: leaf number of Lee Byeong-do index 2

n3: leaf number of Lee Byeong-do index 3

n4: leaf number of Lee Byeong-do index 4

N = n0 + n1 + n2 + n3 + n4

These results are shown in Table 1.

TABLE 1

Potato Plague Control Test Results

[Test Example 2]

Pseudo peronospora Cubensis

Cucumber plants (varieties: epidermal white patches) are grown in a pot in a greenhouse until the development of two leaves. Next, a predetermined concentration prepared by formulating a hydrating agent by the method of Formulation Example 3 described above and diluting it to a predetermined concentration with water is prepared. A suspension of each of the disclosed compounds is sprayed at a rate of 30 ml for three pots using a spray gun (1.0 kg / cm ² ) and air dried.

After keeping the pot in the greenhouse for 5 days, the strain of the strain of young bacteria from the diseased area of the disease-infected cucumber leaves and suspended in demineralized water is sprayed onto the cucumber plants. Immediately after inoculation, the inoculated plants are maintained at a temperature of 18 to 20 ° C. and a relative humidity of 95% or more for 24 hours, and then transferred into a greenhouse (18 to 27 ° C.). After 7 days, the extent of lesion formation was examined and these results are shown in Table 2.

Evaluation criteria and the method of labeling diseases are the same as in Test Example 1.

TABLE 2

Cucumber downy mildew control test result

[Test Example 3]

Cucumber gray mold control test (by Botrytis Cinerea)

Cucumber plants (variety: white hairy white) are grown until the cotyledon stage is reached at the pot in the greenhouse. Next, a suspension of each of the compounds of a predetermined concentration prepared by formulating a hydrating agent by the method of Formulation Example 3, diluted with water to a predetermined concentration, and sprayed (1.0 kg / cm ² ) in 20 ml of three pots Spray in amounts and air dry. After the pot is kept in the greenhouse for 5 days, a strain of a strainer is prepared from gray mold germs previously incubated in PDA medium, and then sprayed on cucumber plants. Immediately after spraying, the inoculum plants were kept at 22-24 ° C. and 95% relative humidity for 5 days. Thereafter, the degree of lesion formation of cotyledons is examined and these results are shown in Table 3.

Evaluation criteria are as follows.

Incidence Index 0: Lesion Area Ratio 0%

Incidence index 1: lesion area ratio 1 to 10%

Incidence index 2: lesion area ratio 11-25%

Incidence Index 3: Lesion Area Ratio 26-50%

Incidence index 4: more than 51% lesion area ratio.

With respect to the whole cotyledons, the incidence index is obtained as described above, and the morbidity is calculated in each test group as in Test Example 1.

TABLE 3

Cucumber gray mold disease control test result

[Test Example 4]

Tomato Plague Control Test (by Phytophthora infestans)

They grow tomato plants (variety: world work) until they are about 25cm tall at the pot in the greenhouse. Next, a suspension of each compound of a predetermined concentration prepared by formulating a hydrating agent by the method of Formulation Example 3, diluted with water to a predetermined concentration, was sprayed (1.0 kg / cm ² ) with 50 ml of three pots. Spray in quantities and air dry.

Yuju suspension is prepared from tomato plague strains previously cultured on potato slices for 7 days, and then sprayed onto tomato plants treated with the respective compounds.

Inoculated plants are maintained at a temperature of 17-19 ° C. and a relative humidity of 95% or more for 6 days, and then the degree of lesion formation is examined.

Evaluation criteria and the method of labeling Byeongdo are the same as in Test Example 1. These results are shown in the 4th table.

TABLE 4

Tomato Plague Control Test Results

[Test Example 5]

Wheat leaf disease control test (by Puccinia recondit)

Growing wheat plants (variety: Norin No. 61) until 5 or 6 leaves develop in pots in the greenhouse. Next, a suspension of each of the compounds of a predetermined concentration prepared by formulating a hydrating agent by the method of Formulation Example 3, diluted with water to a predetermined concentration, and sprayed with a spray gun (1.0 kg / cm ² ) in 30 ml of three pots. Spray in quantities and air dry. These wheat plants are artificially inoculated with the resident of the wheat leaf subtilis strain. Inoculated plants are kept in a greenhouse for 10 days and then the extent of lesion formation is examined. Visually investigate the area ratio of lesions for each plant and determine the disease index. Next, the degree of morbidity of each test group was calculated as in Example 1, and these results are shown in the fifth table.

TABLE 5

Wheat leaf disease control test result

From the results of Test Examples 1 to 5, the compounds according to the present invention are far superior to commercially available fungicides which have conventionally been tolerated against very different kinds of plant diseases including potato blight, cucumber downy mildew, gray mold disease and wheat leaf downy mildew. It can be clearly seen that it has a strong control effect. In addition, it should be noted that the 2-chloro-6-methyl-4-thiocyanopyridine described in the above-mentioned document, which has a relatively chemical structure, has little effect of controlling the aforementioned plant diseases. Also, 2,4-dichloro-5-methylthio-6-thiocyanopyrimidine, which is one of the compounds described on the specification of the above-described patent application (Japanese Patent Publication No. 193,970 / 1985) of the present inventors ( As can be seen from the fact that compared to the control compound D), the compounds according to the present invention have a stronger control effect (an excellent control effect is observed even when inoculating pathogens after 5 days of treatment with other compounds of the present invention). Longer duration than

Therefore, it is clear that the compounds according to the present invention have excellent properties which cannot be predicted from any previous knowledge so far.

From the above description, the dihalogenothiocyanopyrimidine derivatives according to the present invention have a stronger control effect against a wide range of plant diseases, including all kinds of plant diseases, including potato blight, cucumber downy mildew, gray mold and leaf leaf fungus. It can be understood that their persistence also lasts much longer. Thus, it can be clearly seen that the derivatives according to the invention are useful as agrohorticultural fungicides.

In the method for producing a dihalogenothiocyanopyrimidine derivative of the present invention, the introduction of a thiocyano group by the use of an organic acid (particularly formic acid) as a reaction solvent can be obtained very easily and in high yield. It's a breakthrough technology.

Claims (4)

Dihalogenothiocyano pyrimidine derivative characterized by the following general formula (I).

(X and Y represent a halogen atom.) Preparation of the dihalogenothiocyano pyrimidine derivative of the following general formula (I) characterized by reacting the trihalogeno pyrimidine derivative of the following general formula (II) with the thiocyanate of the following general formula (III) Way.

In the above formulas, X and Y are halogen atoms: M is an alkali metal or ammonium. The process according to claim 2, wherein the reaction is carried out in an organic acid. An agricultural and horticultural fungicide comprising the dihalogenothiocyano pyrimidine derivative of the following general formula (I) as an active ingredient.

(X and Y represent a halogen atom.)