JPH032153B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a 2,3-dichloro-N-phenylmaleimide derivative represented by the following general formula and an agricultural and horticultural fungicide containing the compound as an active ingredient. (In the formula, R ₁ represents a difluoromethoxy group or a difluoromethylthio group; R ₂ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, or a difluoromethoxy group.) It can be manufactured by. However, in the following formula, each substituent is as described above. When carrying out the above reaction, it is desirable to use an appropriate solvent.Solvents include aromatic hydrocarbons such as benzene, toluene, and xylene, chlorinated alkanes such as chloroform and carbon tetrachloride, and ketones such as acetone and methyl ethyl ketone. Lower fatty acids such as acetic acid and various other solvents such as dioxane can be used. The amount of nuclear substituted aniline is 2,3-
It may be used in an equimolar amount to dichloromaleic anhydride, but the amount may be adjusted slightly as necessary.
The reaction temperature is preferably selected from the range of 40 to 120°C. The reaction time may generally be 1 to 3 hours. After the reaction, if the solvent used is water-soluble, the reactant is poured into water. Alternatively, if the solvent is insoluble in water, crystals may be precipitated by distilling off the solvent under reduced pressure. If the crude crystals thus obtained are recrystallized from an organic solvent such as acetonitrile, the desired compound can be obtained in good yield. Next, the method of the present invention will be explained in more detail using synthesis examples. Synthesis Example 1 N-(3-chloro-4difluformethoxy)-
Production of 2,3-dichloromaleimide 2,3-dichloromaleic anhydride 83.5g (0.5
mol) in 1000 ml of toluene and heated to reflux while stirring. A solution of 96.5 g (0.5 mol) of 3-chloro-4-difluoromethoxyaniline in 300 ml of toluene was added dropwise thereto. After dropping, heating was continued until water was no longer distilled off by azeotropy, and then heated for another 30 min.
After stirring for several minutes, the solvent was distilled off under reduced pressure. If the precipitated crystals are recrystallized with ethanol, the melting point will be 141.5-142.5.
157 g of N-(4-chloro-3-difluoromethoxyphenyl)-2,3 dichloromaleimide are obtained as pale yellow plate-like crystals. (Yield 92%) Synthesis Example 2 Production of 2,3-dichloro-N-(difluoromethoxy-3-methyl)maleimide 83.5 g (0.5 g) of 2,3-dichloromaleic anhydride
mol) in 1000 ml of toluene and heated to reflux while stirring. -4-difluoromethoxy-
3-Methylaniline 86.5g (0.5mol) Toluene
Add 300ml solution dropwise. After the dropwise addition, the reaction was continued until water was no longer distilled off by azeotropy, and after stirring for an additional 30 minutes, the solvent was distilled off under reduced pressure. When the precipitated crystals are recrystallized with aqueous methanol, the melting point is 133-134.5.
2,3-Dichloro-N-(4-difluoromethoxy-3-methylphenyl)maleimide at °C 149.7
g is obtained as yellow crystals (yield 93%). Example 3 Production of 2-3-dichloro-N[3.4-bis-(difluoromethoxy)phenyl]maleimide 16.7 g (0.1
mol) in 200 ml of toluene and heated to reflux while stirring. 22.5 g (0.1 mol) of 3,4-bisdifluoromethoxyaniline in 50 ml of toluene
Drop the solution. After the dropwise addition, heating is continued until no water is distilled off by azeotropy, and after further stirring for 30 minutes, the solvent is distilled off under reduced pressure. When the precipitated crystals are recrystallized with aqueous ethanol, 2,3
32.1 g of -dichloro-N-[3,4-bis(difluoromethoxy)phenyl]maleimide are obtained. (Yield 86%) Example 4 Production of 2,3-dichloro-N-(4-difluoromethylthiophenyl)maleimide 16.7 g (0.1
mol) in 200 ml of toluene and heated to reflux while stirring. A solution of 17.5 g (10.1 mol) of 4-difluoromethylthioaniline in 50 ml of toluene is added dropwise thereto. After the dropwise addition, heating is continued until no water is distilled off by azeotropy, and after further stirring for 30 minutes, the solvent is distilled off under reduced pressure. When the precipitated crystals are recrystallized from methanol, 2,3-
30.7 g of dichloro-N-(4-difluoromethylthiophenyl)maleimide was obtained as plate-like crystals (yield 95%). The compound has been produced.

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[Table] The compounds of the present invention are effective in controlling a wide range of diseases in agricultural and horticultural crops, and the following are the main examples. Paddy rice, blast disease; beans, sclerotia, brown spot; fruit trees, citrus, black spot, scab; apples, scab, monilia, leaf spot; pears, sclerotia, scab; peach , black spot, gray rot, homopress rot; grapes, downy mildew, late rot, black pox; vegetables,
Cucumber, sclerotia, botrytis, downy mildew, black spot, anthracnose, powdery mildew, vine crack; tomato, late blight, leaf mold ring spot; melon, anthracnose, vine blight; , blight, sclerotia; konjac, root rot; beet, brown spot, etc. There are no restrictions on the amount of spraying, but usually 50-1000g/10a of active ingredient compound (AI) when spraying on fields where crops grow, and 2-8kgA.I when using in soil. /10a is appropriate. Of course, this is just a guideline, and it may be adjusted as necessary, taking into account factors such as the type of crop, the type and degree of damage, the season, the weather, and the dosage form of the drug. As mentioned above, the compound of the present invention is used as a fungicide for agricultural and horticultural purposes, and it can be used as it is or mixed with a carrier (diluent) to form powders, granules, wettable powders, emulsions, oils, and other suitable agents commonly used in agrochemical preparations. It is used as an agent. In this case, spreading agents, emulsifiers, wetting agents, unique agents, etc. are used as necessary.
Further, other types of fungicides, insecticides, herbicides, fertilizers, etc. can also be used or mixed. Example 1 Powder Compounds listed in the table as active ingredients 3 parts Clay 40 parts Talc 57 parts Example 2 Wettable powder Compounds listed in the table 75 parts Polyoxyethylene alkyl allyl ether 9 parts White carbon 16 parts The effects of the compounds of the present invention will be described below. For concrete explanation, typical test examples are shown. However, these are merely examples, and it goes without saying that the application examples of the present invention are not limited to these. Test Example 1 Pear Black Spot Disease Control Test Method A hydrating agent of the compound of the present invention is added to the developed leaves of a potted pear seedling (variety: Nijusseiki) with water at a predetermined concentration (500 ppm).
After air-drying, a conidial suspension of pear black spot fungus cultured in apricot medium was spray inoculated. After inoculation, the plants were kept in a humid room at 27°C for 2 days, and then left in a greenhouse, and disease onset was investigated 6 days after inoculation. The average lesion rate of five expanded leaves in each pot was determined. Each test was repeated 4 times, and the average lesion rate for 20 leaves was determined.

[Table] Test Example 2 Citrus black spot control test Method Immediately after the new leaves of potted citrus seedlings (variety: Ordinary Satsuma) develop, a hydrating powder of the compound of the present invention is diluted to a predetermined concentration (500 ppm) and applied to one pot. A spore suspension of citrus black spot fungus cultured on tangerine branches was sprayed and inoculated one day later. After inoculation, the plants were kept in a humid room at 25°C for 2 days, and then left in a greenhouse. Thirty days after inoculation, the disease development was investigated as follows.

[Table] Test Example 3 Spore germination inhibition test against citrus black spot fungus <Test method> Diaporthe citri conidia cultured on dead citrus branches and a chemical solution were mixed and adjusted so that the number of conidia was approximately 20 per field of view under a microscope at 100x magnification. do. Place 0.02ml of this mixed suspension on a glass slide.
After dropping it and keeping it at a temperature of 27℃ and humidity of 100% for 20 hours, it is examined for spore germination by microscopic examination. Each test was repeated twice, and the presence or absence of germination of approximately 200 spores was examined.

[Table] Test Example 4 Spore germination inhibition test against pear spot fungus <Test method> Alternaria cultured on apricot medium for 7 to 10 days
Mix the conidia of kikuchiana with the drug solution and microscopy.
Adjust so that there are approximately 20 pieces per 100x field of view. Place 0.02ml of this mixed suspension on a glass slide.
After dropping the solution and keeping it at 27℃ and 100% humidity for 20 hours, examine it under a microscope to see if spores have germinated. Each test was repeated twice, and the presence or absence of germination of approximately 200 spores was examined.

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Claims (1)

[Claims] 1. General formula (In the formula, R ₁ represents a difluoromethoxy group or a difluoromethylthio group; R ₂ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, or a difluoromethoxy group.)
Dichloro-N-phenylmailemide derivative. 2 General formula (In the formula, R ₁ represents a difluoromethoxy group or a difluoromethylthio group; R ₂ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, or a difluoromethoxy group.)
An agricultural and horticultural fungicide containing a dichloro-N-phenylmaleimide derivative as an active ingredient.