JPS6254281B2 - - Google Patents

Description

[Detailed description of the invention]

[1] Background Technical Field of the Invention The present invention relates to a plant disease control agent containing a 1-oxoisoindoline derivative as an active ingredient. Antibiotics, which are currently widely used to control sheath blight, are said to lack efficacy due to their low residual efficacy, and there are concerns about the emergence of resistant bacteria.
On the other hand, organic arsenic agents are also used as sheath blight control agents, but because the active ingredients contain heavy metal compounds, there are problems with toxicity to humans and livestock as well as environmental pollution. However, there are many drawbacks to this, and there is a strong demand from various fields for the development of new types of pesticides. [] Summary of the Invention The present invention aims to solve the above-mentioned problems by providing a plant disease control agent containing a 1-oxoisoindoline derivative as an active ingredient. Therefore, the plant disease control agent according to the present invention has the general formula The active ingredient is a 1-oxoisoindoline derivative represented by the formula (wherein R represents an ethyl group or an isopropyl group, respectively). Effects The compound which is the active ingredient of the plant disease control agent according to the present invention generally exhibits control activity against a wide range of agricultural and horticultural crop diseases, but is particularly effective against rice sheath blight, tomato and cucumber seedling blight, and rice leaf blight. It has an excellent pest control effect. This new compound is an extremely low-toxic synthetic compound that does not contain heavy metals, has no practical toxicity to humans, livestock, or fish, and has no phytotoxicity to crops. Therefore, this compound is considered to have sufficient activity to compensate for the drawbacks of the existing drugs mentioned above. [] Detailed Description of the Invention 1 Compound The compound which is the active ingredient of the plant disease control agent according to the present invention is a 2-(2′,
6'-Dialkylphenyl)-1-oxoisoindoline. (In the formula, each R represents an ethyl group or an isopropyl group. The same applies to each of the following formulas.) Among the compounds of general formula (), those in which R is both an ethyl group and an isopropyl group, that is, the following compounds ( 1) and (2) are typical. Compound (1) 2-(2',6'-diethylphenyl)-1-oxoisoindoline compound (2) 2-(2',6'-diisopropylphenyl)-1
-Oxoisoindoline 2 Manufacture of compound The compound which is the active ingredient of the plant disease control agent according to the present invention can be synthesized by any method suitable for introducing or forming the desired substituent or bond in formula (). can do. Some suitable synthetic methods are as follows. (A) N-(2,6-
dialkyl phenyl) phthalimide, as described in the literature (Ann, 247 , 306 or J.Pharmacy).
and Pharmacology 18 , 65-80 (1966) or J.Am.Chem.Soc., 78 , 2349 (1956), a method of synthesis by subjecting to chemical reduction or catalytic reduction reaction (reaction formula A) (B) Method of reacting phthalaldehyde and 2,6-dialkylaniline according to the literature (Ann., 369 , 297) (reaction formula B) (C) A method in which a reactive derivative such as 2-(halomethyl)-benzoic acid or its ester, acid halide, such as chloride, is condensed with 2,6-dialkylaniline by a conventional method (reaction formula C) Y = hydroxyl group, lower alkoxy group, halogen, etc. X = halogen, organic sulfonyloxy group, etc. Specific reaction conditions and others when performing these reactions are determined as appropriate according to the description of the experimental examples below and the method of the above-mentioned literature. Just choose. 3. Usefulness of Compound - Plant Disease Control Agent The plant disease control agent according to the present invention is employed as an agricultural and horticultural agent, especially a fungicide, except that the active ingredient is the above-mentioned compound (). It can take any possible form or usage mode. Specifically, for example, the above-mentioned compound can be used as it is, diluted with a solid powder or other suitable carrier, and used with the addition of an auxiliary agent such as a spreading agent if necessary, or used in the production of agricultural chemicals. Mix various liquid or solid carriers according to commonly used methods, add auxiliary agents such as wetting agents, spreading agents, dispersing agents, emulsifying agents, fixing agents, etc., if necessary, to achieve hydration. It can be used in the form of formulations such as tablets, liquids, emulsions, powders, and granules. In producing these preparations, the liquid carrier used is one that serves as a solvent for the above-mentioned compound or one that can be dispersed or dissolved with the aid of an auxiliary agent. For example, kerosene, dioxane, acetone, dimethyl sulfoxide, animal and vegetable oils, and surfactants, and solid carriers such as clay, kaolin, talc, diatomaceous earth, silica, calcium carbonate, calcium bicarbonate, and the like are used. The content of active ingredient in the preparations thus obtained can be varied within a wide range. For example, when used as a liquid agent, the concentration in the liquid is
Approximately 10 ppm to 500 ppm is appropriate, and in the case of powders or granules, it is desirable to contain the above-mentioned compounds in a range of about 1% to 20%. It goes without saying that the formulation can be formulated at a higher concentration than this and diluted before use. In addition, if circumstances permit, other compatible agricultural and horticultural chemicals or fertilizers may be mixed into the formulation. The pesticidal agent according to the present invention can be used by spraying on the buds of crops, and can also be applied to water surfaces, water, soil surfaces, and soil.
In this case, compatible agricultural and horticultural chemicals or fertilizers may be used. Such agricultural and horticultural chemicals include, for example, fungicides, insecticides, herbicides, and plant growth regulators. The amount of application varies depending on the type and severity of the target disease, the type of target crop, the mode of application, etc., but an example when applying to soil is 0.1 kg per 10 ares.
Application rates of ~10Kg are generally appropriate. 4 Experimental Example 1 Synthesis of Compound Synthesis Example 1 Synthesis of Compound (1) A mixture of 5 g of phthalic anhydride and 5 g of 2,6-diethylaniline was heated to 160° C. and reacted.
Once dissolved, it became a clear liquid, but it completely solidified. The contents were thoroughly crushed, washed with dilute caustic soda solution and dilute hydrochloric acid, and finally washed with water, filtered, and N-(2,
10.7 g of 6-diethylphenyl)phthalimide was obtained. 3 g of this was dissolved in 20 ml of acetic acid, 4 ml of concentrated hydrochloric acid and 3 g of granular tin were added thereto, and the mixture was stirred under heating under reflux for 5 hours. The solvent was distilled off, and the oily residue was washed several times with water and finally washed with an aqueous N-caustic soda solution to crystallize the oil. Immediately diluted with water, thoroughly ground, filtered and washed with water. Dissolve this in 10 ml of methanol, remove insoluble matter by filtration, and concentrate to dryness. Dissolve this again in 10 ml of methanol, remove a small amount of insoluble matter,
When the liquid was concentrated, the residual oil crystallized. 1.6 g of compound (1) was obtained as white crystals. Melting point 108-112℃ (recrystallized from hydrous isopropyl alcohol) Elemental analysis value (%) C ₁₈ H ₁₉ NO (265.36) Calculated value C81.48, H7.22, N5.28 Analytical value C80.52, H7.10, N5.28 NMR (DMSO-d6-TMS) δ; 8.13-7.09
(7H, m, aromatic ring proton); 4.69 (2H,
s, -C H ₂ -N〓); 2.41 (4H, q, 2×
-C H ₂ CH ₃ , J = 7.5Hz); 1.09 (6H, t,
2×-CH ₂ CH ₃ , J=7.5Hz) IR spectrum (Nujol) cm ^-1 : 1675 (C=O),
1615, 1590, 1390, 1337, 1305, 1218,
1171, 1118, 1097, 1063, 885, 820, 800,
780, 740 Mass spectrum (m/e): 265 (M ⁺ ) Synthesis example 2 Synthesis of compound (2) N- synthesized from phthalic anhydride and 2,6-diisopropylaniline in the same manner as in Example 1
1 g of (2,6-diisopropylphenyl)phthalimide was dissolved in 20 ml of acetic acid, 4 ml of concentrated hydrochloric acid and 1.5 g of powdered tin were added, and the mixture was heated under reflux for 3 hours with stirring. The solution was concentrated to dryness, washed thoroughly with water, and the resulting oil was left to stand overnight to crystallize. This was crushed well, washed with dilute hydrochloric acid, filtered and washed with water. Compound (2) as a white crystalline powder
0.86g was obtained. Melting point 154-155℃ (recrystallized from aqueous methanol) Elemental analysis value (%) C ₂₀ H ₂₃ NO (293.41) Calculated value C81.87, H7.90, N4.77 Analytical value C79.40, H7.68, N4 .58 NMR spectrum (CDCl ₃ -TMS) δ; 7.98~
7.03 (7H, m, aromatic proton); 4.50
(2H, s, -CH ₂ -N〓); 2.68 (2H, q,
-CH (CH ₃ ) ₂ × 2, J = 5.0Hz); 1.17
(12H, d, -CH(CH ₃ ) ₂ × 2, J=5.0Hz) Mass spectrum (m/e): 293 (M ⁺ ) IR spectrum (Nujol) cm ^-1 : 1690 (C=O),
1620, 1590, 1390, 1300, 1218, 1165,
810, 753, 733, 723 2 Formulation Example 1 Wettable powder Compound No. (1) 20 parts by weight Clay 10 Diatomaceous earth 65 parts by weight Lignosulfonic acid 3 Polyoxyethylene alkyl allyl ether
2〃 The above component substances are uniformly mixed and pulverized to make a wettable powder composition, and at a predetermined concentration, 100 ~
Spread 150 liters. Formulation Example 2 Powder Compound No. (2) Compound 3 parts by weight Calcium stearate 1 Silicic anhydride powder 1 Clay 48 Talc 47 A powder composition prepared by mixing and grinding the above, 10 parts by weight
Spread 4 kg per area. Formulation Example 3 Granules Compound No. (1) 8 parts by weight Clay 89 Carboxymethyl cellulose 3 Granules obtained by mixing the above ingredients, adding an appropriate amount of water, kneading, and drying. composition, 10
3Kg of granules are dispersed per area. 3 Medicinal Efficacy Test Test Example 1 Antibacterial test against plant pathogenic bacteria The growth of hyphae on an agar plate was investigated using the plant pathogenic bacteria shown in the table below as test bacteria. That is, the compound of the present invention is mixed into a potato agar medium at a concentration of 100 ppm, poured into a shear dish and solidified, and the test bacteria (punched with a cork borer with a diameter of 7 mm) separately cultured on an agar plate is placed in the center of the medium. ) was inoculated. At 28°C (Botrytis
cinerea (botrytis fungus) and Pythium sp.
(Wheat brown snow rot fungus) after culturing for 72 hours at 10°C.
By measuring the diameter of growing hyphae,
The degree of antibacterial properties was compared.

【table】

[Table] Test Example 2 Control effect test on rice sheath blight A predetermined concentration of the hydrating powder produced in Formulation Example 1 was applied to paddy rice (variety Jukoku) at the heading stage cultivated in a 1/5000 are Wagner pot. The prepared spray liquid was prepared using a chemical dispersion equipment spray gun (3 kg/
cm ² ) at a rate of 70 ml/3 pots. On the day of the inoculation, immediately after air-drying, the sheath blight bacteria obtained by flat culture on a peptone-added potato decoction agar medium for 48 hours were punched out using a cork borer with a diameter of 0.5 cm. The vaccine was inserted 15 cm from the tube and inoculated. It was also conducted to see the effectiveness in preventing invasion. On the 7th day after spraying, the inoculated plots were left standing in a glass greenhouse for 7 days after spraying with the chemical solution and air-dried, and then inoculated in the same manner as the inoculated plots on the same day. After inoculation, each pot was covered with a vinyl cylinder and kept at 30°C during the day and at night in both the same-day and 7-day post-inoculation areas to encourage the invasion of sheath blight bacteria.
Leave it in a glass greenhouse at 24℃ to develop the disease, and then inoculate it.
After 10 days, the lesion length of the diseased pods was measured, and the control value was calculated according to the following formula. At the same time, the occurrence of drug damage was also visually observed.

【table】

[Table] Test Example 3 Seedling damping-off control test A seedling damping-off bacterium (Rhizoctonia type A bacterium) was cultured on a potato decoction agar medium, mixed with 3 times the amount of rice sugar and ground to prepare an inoculum. did. Using tomatoes (variety Hikari) and cucumbers (variety Satsuki Midori) as test crops, 20 germinated seeds per pot were sown and covered with soil in 1/5000 Ahl Wagner pots filled with sterilized field soil, and the above-mentioned inoculum and A mixture of equal amounts of sterilized field soil was uniformly sprayed and inoculated onto the soil. After inoculation, let stand in a constant temperature room at 28°C for 48 hours, then prepare the compound of the present invention in Formulation Example 1 to a predetermined concentration to make an irrigation solution, and uniformly pour 100ml of the drug solution per pot onto the ground surface with a pipette. Applied. Thereafter, in order to facilitate the progress of invasion of the inoculated bacteria, the plants were transported to a glass greenhouse at a temperature of 30°C to 28°C, and the soil in the pot was kept in a slightly dry condition to develop the disease. The investigation is
The number of germination and the number of healthy seedlings up to 3 weeks after sowing were investigated, and the germination rate relative to the number of sown grains and the percentage of healthy seedlings relative to the number of germination were calculated and described.

[Table] Test Example 4 Test for control effect on rice leaf blight Paddy rice (variety Tokoku) was grown in a 1/5000 are Wagner pot, and a predetermined amount of the granules produced in Formulation Example 3 was applied to the water surface of the pot. . Inoculation with rice bacterial leaf blight was carried out by inoculating 10 ⁸ bacteria/ml with a single needle 10 days after application. In the investigation, on the 10th day after inoculation, the lesion length was measured on a total of 50 inoculated leaves in 3 pots in each group, the control value was calculated using the formula in Test Example 1, and chemical damage was also observed and investigated at the same time.

【table】

Claims (1)

[Claims] 1. General formula A plant disease control agent containing a 1-oxoisoindoline derivative represented by the formula (wherein R represents an ethyl group or an isopropyl group, respectively) as an active ingredient.