Acetohydroxy acid synthase inhibitor, preparation method thereof and application of acetohydroxy acid synthase inhibitor as herbicide

Abstract

The invention relates to an inhibitor compound, and aims to provide an acetohydroxy acid synthase inhibitor, a preparation method thereof and application of the acetohydroxy acid synthase inhibitor as a herbicide. The structural formula of the compound is as shown in formula (I), and the compound specifically inhibits the activity of p-acetohydroxyacid synthetase or a mutant W574L thereof in plants. The invention further provides an application method of the compound as an agricultural chemical herbicide. The compound has good enzyme inhibition activity on wild acetohydroxyacid synthetase and / or a mutant W574L thereof, so that the compound can be used as an agricultural chemical herbicide for preventing and treating various weeds in the agricultural field; the herbicide can be used as pre-emergence and post-emergence herbicides, can be used for preventing and treating various field weeds, and has a special effect on preventing and treating worst weeds, namely moleplant seeds; the weeding composition has the characteristics of low dosage, excellent weeding activity, wide weed control spectrum, good conductivity, wide use window period, safety to rice and the like.

Description

Technical Field

[0001] The present invention relates to an inhibitor compound, in particular to an acetohydroxyacid synthase inhibitor, a preparation method thereof and an application thereof as a herbicide. The target of the compound is acetohydroxyacid synthase or its mutant W574L, and it can be used as a herbicide for weed control in the agricultural field. The product has a special effect on controlling the malignant weed Leptochloa chinensis, and is superior to the commonly used commercial herbicides cyhalofop-butyl and penoxsulam in controlling resistant Leptochloa chinensis. Background Art

[0002] Leptochloa chinensis (L.) Nees. belongs to the grass family and is a worldwide malignant weed. Leptochloa chinensis has a large number of seeds (an average of 45,000 seeds per plant) and a strong tillering ability (the number of tillers can be as high as 48.2). In addition, its drought-tolerant and moisture-loving characteristics make it very suitable for Leptochloa chinensis to occur and spread rapidly in rice fields, evolving into the main weed population in rice fields, competing with rice and causing serious rice yield reductions. With the promotion and development of direct seeding and no-tillage technologies in rice fields, the damage caused by Leptochloa chinensis is becoming increasingly serious. Studies have shown that the density of Leptochloa chinensis can reach 21 plants / m 2 When the temperature is too high, the rice yield can be reduced by 44.36%.

[0003] In the prevention and control of Leptochloa chinensis, it is difficult to control it by time difference because Leptochloa chinensis and rice seedlings basically emerge simultaneously. In terms of chemical control, there are fewer herbicide options for Leptochloa chinensis. At present, aryloxyphenoxypropionate (APP) herbicides such as cyhalofop-butyl, fenoxaprop-butyl and oxadiazine are mainly used for farmland weed control. This type of herbicide is an acetyl-coenzyme A carboxylase (ACCase) inhibitor and can only be used for post-emergence control of Leptochloa chinensis.

[0004] Cyhalofop-butyl is the most widely used herbicide in rice fields, but long-term and excessive use of the same type of herbicide has also led to the rapid occurrence of resistant Leptochloa chinensis. The resistance coefficient of some Leptochloa chinensis populations resistant to cyhalofop-butyl has reached 191.6 times. In addition, in Southeast Asia, China and other regions, it has been found that Leptochloa chinensis resistant to ACCase inhibitor herbicides also has cross-resistance to inhibitors of other targets, such as propanil (photosynthetic system II inhibitor herbicide) and dichloroquine (growth hormone herbicide).

[0005] The mechanism of insecticide resistance in Leptochloa chinensis includes target resistance and non-target resistance. The target resistance of Leptochloa chinensis reported so far mainly comes from amino acid mutations at sites 1781, 1999 and 2027; the generation of non-target resistance may be related to the enhanced activity of glutathione S-transferase (GSTs), which can increase the metabolic decomposition rate of weeds to herbicides, thus making Leptochloa chinensis resistant to insecticides.

[0006] Acetohydroxyacid synthase (AHAS) is a key enzyme that catalyzes the first stage of the biosynthesis pathway of branched-chain amino acids - leucine, valine and isoleucine. Acetohydroxyacid synthase can catalyze two molecules of pyruvate to produce α-acetolactate, or one molecule of pyruvate and α-ketobutyric acid to produce 2-acetyl-2-hydroxybutyrate. Acetohydroxyacid synthase inhibitors inhibit the catalytic activity of AHAS in plants, thereby blocking the synthesis of branched-chain amino acids, affecting protein synthesis and further inhibiting cell division, thereby causing plant tissues to lose green and yellow, inhibiting plant growth, and ultimately leading to plant death. In addition, hydroxyacid synthase only exists in plants, fungi and bacteria, not in animals, and inhibitors designed with this as a target have extremely high biosafety for mammals. At the same time, this type of herbicide has a low application dose, has a broad spectrum of herbicidal activity, and is highly safe for crops. It is currently the most important type of herbicide.

[0007] However, the existing commercial herbicides targeting acetohydroxyacid synthase cannot effectively control resistant Leptochloa chinensis when used at the recommended field dose due to the special structure of their compound skeletons. In addition, there is no cross-resistance between herbicides targeting AHAS and ACCase inhibitor herbicides.

[0008] Based on the above reasons, it is urgent and of great significance to construct herbicides with skeleton structures different from existing acetohydroxyacid synthase inhibitors and use them to control resistant Leptochloa chinensis. Summary of the invention

[0009] The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and provide an acetohydroxyacid synthase inhibitor and a preparation method thereof and an application thereof as a herbicide.

[0010] To achieve the above object, the solution of the present invention is:

[0011] Provided is an acetohydroxyacid synthase inhibitor, the structural formula of the compound is shown in formula (I):

[0012]

[0013] The compound specifically inhibits the activity of acetohydroxy acid synthase or its mutant W574L in plants.

[0014] The present invention further provides a method for preparing the acetohydroxyacid synthase inhibitor, and the synthetic route of the preparation method is shown in the following formula:

[0015]

[0016]

[0017] As a preferred embodiment of the present invention, the preparation method specifically comprises the following steps:

[0018] (1) using methanol or ethanol as the solvent of the reaction system, reacting 4-(4-chlorophenoxy)aniline with salicylaldehyde to prepare the corresponding Schiff base; controlling the molar ratio of 4-(4-chlorophenoxy)aniline to salicylaldehyde to be 1:1.2, the reaction temperature to be room temperature, and the reaction time to be 2 hours;

[0019] (2) using sodium borohydride or potassium borohydride as a reducing agent and methanol or ethanol as a solvent of the reaction system to reduce a Schiff base to obtain a benzylamine compound; the molar ratio of the Schiff base to the reducing agent is controlled to be 1:1.5, the reaction temperature is room temperature, and the reaction time is 0.5 hours;

[0020] (3) The target product, acetohydroxyacid synthase inhibitor, is prepared by reacting a benzylamine compound with 2-methylsulfonyl-4,6-dimethoxypyrimidine; potassium carbonate or cesium carbonate is used as a base, and 1,4-dioxane is used as a reaction solvent; the molar ratio of the benzylamine compound, 2-methylsulfonyl-4,6-dimethoxypyrimidine and the base is controlled to be 1:1.2:1.2, the reaction temperature is the boiling point of the solvent, and the reaction time is 1 hour; the target product is finally obtained and purified by silica gel chromatography or recrystallization.

[0021] The present invention further provides a herbicidal composition comprising a herbicidally active amount of the acetohydroxyacid synthase inhibitor according to claim 1 and at least one formulation adjuvant.

[0022] The present invention further provides a method for preparing a herbicidally active composition, which comprises mixing a herbicidally active amount of the acetohydroxyacid synthase inhibitor according to claim 1 and at least one formulation adjuvant.

[0023] The present invention further provides the use of the aforementioned acetohydroxyacid synthase inhibitor as an agricultural chemical herbicide, wherein the compound specifically inhibits the activity of acetohydroxyacid synthase or its mutant W574L in plants.

[0024] The present invention further provides a method for using the aforementioned acetohydroxyacid synthase inhibitor as an agricultural chemical herbicide to control resistant Leptochloa chinensis, which comprises applying an herbicidally active amount of the acetohydroxyacid synthase inhibitor to the leaves of the resistant Leptochloa chinensis in the pre-bud or post-bud stage, and the compound specifically inhibits the activity of acetohydroxyacid synthase or its mutant W574L in the resistant Leptochloa chinensis plant.

[0025] The present invention further provides a method for using the above-mentioned acetohydroxyacid synthase inhibitor as an agricultural chemical herbicide, which is to apply a herbicidally active amount of the acetohydroxyacid synthase inhibitor to the leaves of weeds, and the compound specifically inhibits the activity of acetohydroxyacid synthase or its mutant W574L in the weed plant body; the weeds are any one of the following: Leptochloa chinensis, Echinochloa crusgalli, Digitaria sanguinalis, Amaranthus retroflexus, Goosegrass, Setaria viridis, Poa annua, Chenopodium album, Portulaca oleracea, Setaria viridis, Revolution grass, Brassica juncea, Polygonum syringae, Cyperus difformis, Achyranthes bidentata, Dalbergia vaginalis or Cyperus rotundus.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The acetohydroxyacid synthase inhibitor provided by the present invention has good enzyme inhibitory activity against wild-type acetohydroxyacid synthase and / or its mutant W574L, and can therefore be used as an agricultural chemical herbicide for the prevention and control of various weeds in the agricultural field.

[0028] 2. The acetohydroxyacid synthase inhibitor provided by the present invention can be used as a pre-emergence and post-emergence herbicide, and the objects of control include barnyard grass, crabgrass, Amaranthus retroflexus, Goosegrass, Setaria viridis, Poa annua, Chenopodium album, Purslane, Setaria officinalis, revolutionary grass, mustard, Polygonum syringae, Cyperus difformis, Amaranthus chinensis, Dalbergia tongue, Cyperus rotundus, etc.

[0029] 3. The acetohydroxyacid synthase inhibitor provided by the present invention is particularly effective in preventing and controlling the malignant weed Leptochloa chinensis, and its control effect on resistant Leptochloa chinensis is better than the commercial herbicides cyhalofop-butyl and penoxsulam.

[0030] 4. The acetohydroxyacid synthase inhibitor provided by the present invention is used as an agricultural chemical herbicide for weed control in the agricultural field, and has the characteristics of low dosage, excellent herbicidal activity, broad weed control spectrum, good conductivity, wide use window period, and safety to rice. In particular, it can effectively control Leptochloa chinensis, and has good effect and great potential in controlling resistant Leptochloa chinensis. DETAILED DESCRIPTION

[0031] The following specific examples are used to further illustrate the present invention, but the present invention is by no means limited to these examples.

[0032] Example 1: This example is used to illustrate the synthesis of the acetohydroxyacid synthase inhibitor (I) provided by the present invention.

[0033] The synthetic route of the preparation method is shown below:

[0034]

[0035] Salicylaldehyde (4.44 g, 36 mmol) was added dropwise to a solution of 4-(4-chlorophenoxy)aniline (6.61 g, 30 mmol) in anhydrous methanol (150 mL). After the reaction was stirred at room temperature for 2 hours, TLC was used to detect the disappearance of the raw material to obtain the corresponding Schiff base. Sodium borohydride (1.71 g, 45 mmol) was added to the above reaction system three times and reacted at room temperature for 0.5 hours. The solvent was removed under reduced pressure to obtain a crude product of the benzylamine compound. The crude product of the benzylamine compound was dissolved in 1,4-dioxane (150 mL), and anhydrous cesium carbonate (11.73 g, 36 mmol) and 2-methylsulfonyl-4,6-dimethoxypyrimidine (7.86 g, 36 mmol) were added. After the reaction was heated to reflux for 1 hour, TLC was used to detect the disappearance of the raw material, and the solvent 1,4-dioxane was removed under reduced pressure. Water was added to the crude residue and extracted with ethyl acetate (150 mL×3). The combined organic phases were washed with brine, dried over anhydrous sodium sulfate, and the solvent was removed under reduced pressure to obtain a crude product of compound (I). The crude product was recrystallized from ethyl acetate to obtain a white solid product, namely, an acetohydroxyacid synthase inhibitor (9.81 g, 70.3%).

[0036] The physicochemical properties of inhibitor (I) are as follows:

[0037] Solid; Melting point: 127.8-128.9℃; 1 H NMR (400MHz, DMSO-d6) δ7.43(dd,J=7.5Hz,1.4,1H),7.31(td,J=6.4Hz,5.9,2.3,3H),7.23(td,J=7.4Hz,1.2,1H),7.17(dd,J=7. 9Hz,1.2,1H),6.87-6.81(m,2H),6.80-6.75(m,2H),6.57-6.49(m,2H),6.18(s,1H),6.00(s,1H),4.15(s,2H),3.76(s,6H).HRMS m / z(ESI-TOF):calcd.for C 25 H 23 ClN3O4[M+H] + :464.1372,found 464.1372.

[0038] Example 2: This example is used to illustrate the inhibitory activity of the acetohydroxyacid synthase inhibitor (I) provided by the present invention on wild-type acetohydroxyacidase and its mutant W7574L.

[0039] The enzyme activity test was carried out according to the method described in the literature "Anal Biochem 1988, 171, 173-179", and it was found that the inhibitor (I) provided by the present invention has an activity against the wild type of acetohydroxyacid synthase (IC 50 and K i :μM) and its mutant W574L (IC 50 :μM) inhibitory activity. IC 50 : Half inhibitory concentration. K i : Inhibition constant, specific results are shown in Table 1.

[0040] The binding ability of inhibitor (I) to wild-type acetohydroxyacid synthase (K D :μM). K D : The equilibrium dissociation constant of the inhibitor (I) and the protein. The specific results are shown in Table 1.

[0041] Table 1

[0042] AHAS <![CDATA[IC 50 (μM)]]> <![CDATA[K i -Wild Type (μM)]]> <![CDATA[K D -Wild Type (μM)]]> wild type 75.4 39.4 3.8 W574L 72.8 - -

[0043] As can be seen from Table 1, inhibitor (I) has good inhibitory activity against wild-type AHAS, and its activity reaches the micromolar level, indicating that it is an acetohydroxyacid synthase inhibitor. Inhibitor (I) has comparable enzyme inhibitory activity against wild-type AHAS and its W574L mutant, indicating that the inhibitor also has good adaptability to its mutant.

[0044] Since the molecular skeleton structure of inhibitor (I) is different from all existing commercial acetohydroxyacid synthase inhibitors, it is a novel inhibitor with good adaptability to acetohydroxyacid synthase. It is important that Example 2 lays the molecular foundation for the development of inhibitor (I) into a new herbicide.

[0045] Example 3: This example is used to illustrate the post-emergence herbicidal activity test of the acetohydroxyacid synthase inhibitor (I) provided by the present invention on resistant Leptochloa chinensis.

[0046] Test agent: Inhibitor (I).

[0047] Control agent: cyhalofop-butyl.

[0048] Test target: ACCase-resistant Leptochloa chinensis.

[0049] Planting method: The test soil is sandy soil, silt soil and clay, which are prepared in a mass ratio of 1:1:1. After mixing and stirring evenly, they are used as special soil for the test. Take a flower pot with a diameter of 8 cm, fill the soil to 3 / 4 of the flower pot, place the flower pot in a large stainless steel pot with 5 cm deep water, and wait until the soil is completely moistened. Sow 10-15 target weed seeds mentioned above in the flower pot. After sowing, cover with 0.2-0.5 cm of soil, and then place it in a greenhouse for cultivation. Replenish water every day to keep the soil moisture at around 80% (relative humidity). The greenhouse temperature is 28±2℃, and the relative humidity is 60-80%.

[0050] Application method: Use the greenhouse potting method, wait until the weeds grow to the 2-leaf stage, and then spray the stems and leaves. Repeat twice for each treatment, set a blank control (distilled water as the blank control), and the treatment dosage is shown in Table 2. After spraying, let it stand indoors, and after the weed leaves absorb the liquid, move it into the greenhouse for cultivation, and the growth temperature is 28±2℃.

[0051] Investigation method: Regularly observe the growth and reaction symptoms of weeds after treatment. 21 days after the drug application, cut the above-ground part of the target weeds and weigh the fresh weight to calculate the fresh weight inhibition rate. The fresh weight inhibition rate is calculated according to the following formula. The specific test results are shown in Table 2.

[0052] F=(CT) / C×100

[0053] Where: F: fresh weight inhibition rate (%); C: fresh weight of the aboveground part of blank control plants (g); T: fresh weight of the aboveground part of treated plants (g).

[0054] Table 2

[0055]

[0056] As shown in Table 2, the control effect of cyhalofop-butyl on resistant Leptochloa chinensis at the recommended field dose (75 g ai / ha) was only 17.3%, while at a high dose (300 g ai / ha), the control effect on resistant Leptochloa chinensis was only 59.5%. At the same dose (75 g ai / ha), the control effect of inhibitor (I) was 86.2%, and even at a lower dose of 37.5 g ai / ha, it still had a control effect of 83.4%.

[0057] The results showed that the activity of inhibitor (I) against ACCase-resistant Leptochloa chinensis was significantly better than that of cyhalofop-butyl, and cyhalofop-butyl could no longer effectively control resistant Leptochloa chinensis at the recommended field dose. Therefore, inhibitor (I) targeting acetohydroxyacid synthase can replace cyhalofop-butyl for the control of ACCase-resistant Leptochloa chinensis.

[0058] Example 4: This example is used to illustrate the effect of the leaf age of Leptochloa chinensis on the herbicidal activity of the acetohydroxyacid synthase inhibitor (I) provided by the present invention.

[0059] Test agent: Inhibitor (I).

[0060] Control agent: cyhalofop-butyl.

[0061] Test target: Sensitive Leptochloa chinensis.

[0062] Planting method: Same as Example 3. Growth temperature 25±2°C.

[0063] Application method: Use the greenhouse pot method, wait for the weeds to grow to 0, 1, 2, 3, and 4 leaf stages, and then spray the stems and leaves. Each treatment is repeated 3 times, and a blank control (distilled water is used as the blank control) is set. The treatment dosage is shown in Table 3.

[0064] After spraying, leave the plants to stand still indoors until the weed leaves absorb the liquid, then move them into the greenhouse for cultivation at a growth temperature of 25±2℃.

[0065] Survey method: Regularly observe the growth and reaction symptoms of weeds after treatment. 21 days after the drug application, cut the above-ground part of the target weeds and weigh the fresh weight to calculate the fresh weight inhibition rate. The fresh weight inhibition rate is calculated according to the following formula. The specific test results are shown in Table 3.

[0066] F=(CT) / C×100

[0067] Where: F: fresh weight inhibition rate (%); C: fresh weight of the aboveground part of blank control plants (g); T: fresh weight of the aboveground part of treated plants (g).

[0068] Table 3

[0069]

[0070] As shown in Table 3, at the same dosage (75 g ai / ha), the inhibitor (I) had a control effect of 96.2-99.7% on the fresh weight of sensitive Leptochloa chinensis at the 0-1 leaf stage, which was better than the control agent cyhalofop-butyl.

[0071] For weeds in the 2-4 leaf stage, at a dosage of 75 g ai / ha, the fresh weight control effect of inhibitor (I) was 71.3-82.9%; when the dosage was increased to 300 g ai / h, the fresh weight control effect on weeds in the 2-4 leaf stage was 84.1-97.1%. Therefore, the dosage can be appropriately increased for older Leptochloa chinensis.

[0072] The results of Example 4 show that inhibitor (I) exhibits good herbicidal activity against weeds in the 0-4 leaf stage, and can be used as a pre-emergence herbicide (sprayed at the 0-1 leaf stage) or a post-emergence herbicide (sprayed at the 2-3 leaf stage). Therefore, inhibitor (I) is a pre-emergence and post-emergence herbicide with a wider application window than cyhalofop-butyl.

[0073] Example 5: This example is used to illustrate the effect of application temperature on the post-emergence herbicidal activity of the acetohydroxyacid synthase inhibitor (I) provided by the present invention.

[0074] Test agent: Inhibitor (I).

[0075] Control agent: cyhalofop-butyl.

[0076] Test target: Sensitive Leptochloa chinensis.

[0077] Planting method: Example 3.

[0078] Application method: Use the greenhouse pot method, wait until the weeds grow to the 3-4 leaf stage, and then spray the stems and leaves. Repeat 3 times for each treatment, and set a blank control (distilled water is used as the blank control). The treatment dosage is shown in Table 4.

[0079] After spraying, place the seeds in an artificial climate box for cultivation immediately. Set the cultivation temperature (L / D): 35°C / 30°C, 25°C / 20°C, 15°C / 10°C, relative humidity 60-80%, and light (L / D) 12 / 12 hours.

[0080] Investigation method: Regularly observe the growth and reaction symptoms of the treated weeds. 21 days after the drug application, cut the aboveground part of the target weeds and weigh the fresh weight to calculate the fresh weight inhibition rate. The calculation formula for the fresh weight inhibition rate is the same as that in Example 3. The specific test results are shown in Table 4.

[0081] Table 4

[0082]

[0083] As shown in Table 4, at 30-35°C, the inhibitor (I) at a dosage of 75 g ai / ha had a protective effect of 95.4% on Leptochloa chinensis at the 3-4 leaf stage, showing extremely high herbicidal activity. At the same dosage, the inhibitor (I)'s fresh weight inhibition rate on Leptochloa chinensis increased with increasing temperature, and the herbicidal activity on Leptochloa chinensis was positively correlated with temperature, indicating that the inhibitor (I) is a drug that is compatible with the rice growth period.

[0084] Example 6: This example is used to illustrate the absorption of the acetohydroxyacid synthase inhibitor (I) provided by the present invention by plants.

[0085] Test agent: Inhibitor (I).

[0086] Control agent: cyhalofop-butyl.

[0087] Test target: Sensitive Leptochloa chinensis.

[0088] Planting method: same as in Example 3.

[0089] Application method: Use the greenhouse pot method, wait until the weeds grow to the 3-4 leaf stage, and apply the pesticide by stem and leaf spray and root irrigation respectively. Each treatment is repeated 3 times, and a blank control (distilled water is used as the blank control) is set. The treatment dosage is shown in Table 5.

[0090] After the pesticide treatment, the plants were placed in a greenhouse for cultivation. During the test, the greenhouse temperature was 25°C ± 2°C and the relative humidity was 60% to 80%.

[0091] Investigation method: Regularly observe the growth and reaction symptoms of the treated weeds. 21 days after the drug application, cut the aboveground part of the target weeds and weigh the fresh weight to calculate the fresh weight inhibition rate. The calculation formula for the fresh weight inhibition rate is the same as in Example 3. The specific test results are shown in Table 5.

[0092] Table 5

[0093]

[0094] The test results of two application methods, stem and leaf spray treatment and root irrigation treatment, showed that inhibitor (I) and the control agent cyhalofop-butyl had serious inhibition on the fresh weight of the aboveground and underground parts of Leptochloa chinensis. Under the same dosage treatment, the inhibition rate of inhibitor (I) on the fresh weight of the underground part of Leptochloa chinensis was slightly higher than that of the aboveground part. The above results show that inhibitor (I) can be absorbed by plants through roots, stems and leaves.

[0095] Example 7: This example is used to illustrate the safety test of rice treated with the acetohydroxyacid synthase inhibitor provided by the present invention after post-emergence stem and leaf treatment.

[0096] Test agent: Inhibitor (I).

[0097] Test target: Rice (Japonica 9746).

[0098] Planting method: same as in Example 3.

[0099] Application method: Same as Example 3. When the rice grows to the 3-4 leaf stage, the stem and leaf spray treatment is carried out, and each treatment is repeated 3 times, and a blank control (distilled water is used as the blank control) is set. The treatment dosage is shown in Table 6.

[0100] After spraying, the rice is left to stand still indoors until the liquid on the rice leaves is dry, and then moved into a greenhouse for cultivation. The growth temperature is 25±8°C and the relative humidity is 60-80%.

[0101] Investigation method: Regularly observe the growth and reaction symptoms of the crops after treatment. 30 days after the drug application, measure the plant height and fresh weight of rice, and calculate the plant height and fresh weight inhibition rate. The fresh weight inhibition rate is calculated in the same way as in Example 3, and the plant height inhibition rate is calculated according to the following formula. The specific test results are shown in Table 6.

[0102] H=(CT) / C×100

[0103] Wherein: H: plant height inhibition rate (%); C: blank control plant height (cm); T: treated plant height (cm).

[0104] Table 6

[0105] Dosage (g ai / ha) Plant height inhibition rate (%) Fresh weight inhibition rate (%) 180 6.89 22.37 150 6.36 5.95 120 7.78 3.06 90 6.33 4.15 60 5.71 -19.49 30 -2.25 -38.42

[0106] As shown in Table 6, within the dosage range of 150 g ai / ha, the inhibitor (I) had an inhibition rate of less than 10% on the plant height and fresh weight of rice. This dosage was safe for rice seedlings at the 3-4 leaf stage. 10 The value was ≤150 g ai / ha. At low doses (≤60 g ai / ha), inhibitor (I) promoted rice growth.

[0107] Example 8: This example is used to illustrate the test of the acetohydroxyacid synthase inhibitor (I) provided by the present invention for controlling Leptochloa chinensis in the field.

[0108] Test agent: Inhibitor (I).

[0109] Control drugs: penoxsulam and cyhalofop-butyl.

[0110] Application method: spray the pesticide in the evening after rice grows to 3-4 leaves and Leptochloa chinensis grows to 2-3 leaves. The area of ​​each treatment plot is 27.5 square meters, and each treatment is repeated 3 times. A blank control (distilled water is used as the blank control) is set. The treatment dosage is shown in Table 7.

[0111] Investigation method: Regularly observe the growth and reaction symptoms of weeds after treatment, and investigate the plant control effect and fresh weight control effect 40 days after the drug application. Take samples at 3 points in each plot, 0.10 square meters per point, a total of 0.30 square meters, record the number of Leptochloa chinensis plants and fresh weight in the point, and calculate the plant control effect and fresh weight control effect. The plant control effect and fresh weight control effect are calculated according to the following formula. The specific test results are shown in Table 7.

[0112] Plant protection effect (%) = (N C –N T ) / N C ×100

[0113] Fresh weight protection effect (%) = (W C –W T ) / W C ×100

[0114] Where: N C : Number of weeds in the blank control area; N T : Number of weeds in the treatment area; W C : Fresh weight of weeds in blank control area; W T : Fresh weight of weeds in treatment area.

[0115] Table 7

[0116]

[0117] As shown in Table 7, the investigation 40 days after the application found that the inhibitor (I) had a very high control effect on Leptochloa chinensis at two different doses, which was significantly better than penoxsulam. When cyhalofop-butyl was used to control resistant Leptochloa chinensis in the field, its dosage had to be as high as 750 g ai. / ha, which was about 10 times the recommended dosage in the registration; while the inhibitor (I) had a plant control effect and fresh weight control effect of 100% at a dose of 150 g ai / ha 40 days after the application, which could effectively control the resistant Leptochloa chinensis.

[0118] The above results show that inhibitor (I) can effectively control resistant Leptochloa chinensis, and its efficacy is better than cyhalofop-butyl and penoxsulam.

[0119] Example 9: This example is used to illustrate the post-emergence weed control spectrum test of the acetohydroxyacid synthase inhibitor (I) provided by the present invention.

[0120] Test agent: Inhibitor (I).

[0121] Test targets: grass weeds, broadleaf weeds, and sedges.

[0122] Planting method: Same as Example 3. Sow the weed seeds in pots, ensuring that there are 20-30 seeds in each pot, and then place them in a greenhouse for cultivation. Add water every day to keep the soil moisture at about 80% (relative humidity), the growth temperature at 25±2°C, and the relative humidity at 60-80%.

[0123] Application method: Use the greenhouse potting method. When the grass weeds and sedges grow to the 1-1.5 leaf stage and the broadleaf weeds grow to the true leaf stage, spray the stems and leaves. Repeat 3 times for each weed, and set a blank control (distilled water as a blank control). The treatment dose is 75g ai / ha. After spraying, let it stand in the room. After the weed leaves absorb the liquid, move it into the greenhouse for cultivation. The growth temperature is 25±2℃.

[0124] Investigation method: Regularly observe the growth and reaction symptoms of the treated weeds. Twenty days after the application, the herbicidal activity of the inhibitor (I) against each target weed was evaluated by visual inspection. The evaluation criteria for the visual inspection of plant toxicity are shown in Table 8, and the specific test results are shown in Table 9.

[0125] Table 8

[0126]

[0127] Table 9

[0128]

[0129] As shown in Table 9, under the treatment of 75 g ai / ha, 6 weeds including bluegrass, goosegrass, quinoa, Amaranthus retroflexus, Cyperus dimorphus and Brassica juncea were highly sensitive to inhibitor (I) (90-95%); 7 weeds including purslane, crabgrass, golden foxtail, revolutionary grass, cyperus, barnyard grass and foxtail were moderately sensitive to it (80-85%); while champignon, ramie and cassia were less sensitive to it. The above results show that inhibitor (I) has a wide spectrum of weed control and has good herbicidal activity against the main weeds in rice fields.

[0130] The acetohydroxyacid synthase inhibitor of the present invention can be used as an active ingredient of a herbicide, and can be prepared into various emulsions, granules, etc. by using a pesticide preparation processing method, adding organic solvents, surfactants, carriers and other auxiliary agents for weed control of crops.

[0131] Example 10: Emulsion

[0132] Heat and stir 5% of inhibitor (I), 5% of Nongru No. 500 (calcium salt), 5% of Nongru No. 602, 5% of N-methyl-2-pyrrolidone and 80% of solvent oil No. 330 to obtain an emulsion.

[0133] When applied in the field, spraying operation is performed with reference to the dosage of the acetohydroxyacid synthase inhibitor in each example.

[0134] Example 11: Wettable powder

[0135] 10% of inhibitor (I), 5% of lignin sulfonate (Mg), 1% of lauryl alcohol polyoxyethylene ether (JFC), 40% of diatomaceous earth and 44% of light calcium carbonate are uniformly mixed and crushed to obtain a wettable powder.

[0136] When applied in the field, the broadcasting operation is carried out with reference to the dosage of the acetohydroxyacid synthase inhibitor in each example.

Claims

1. An acetohydroxyacid synthase inhibitor, characterized in that The structural formula of the compound is shown in formula (I): The compound specifically inhibits the activity of acetohydroxy acid synthase or its mutant W574L in plants.

2. The method for preparing the acetohydroxyacid synthase inhibitor according to claim 1, characterized in that: The synthetic route of the preparation method is shown below:

3. The method according to claim 2, characterized in that The specific steps include: (1) using methanol or ethanol as the solvent of the reaction system, reacting 4-(4-chlorophenoxy)aniline with salicylaldehyde to prepare the corresponding Schiff base; controlling the molar ratio of 4-(4-chlorophenoxy)aniline to salicylaldehyde to be 1:1.2, the reaction temperature to be room temperature, and the reaction time to be 2 hours; (2) using sodium borohydride or potassium borohydride as a reducing agent and methanol or ethanol as a solvent of the reaction system to reduce a Schiff base to obtain a benzylamine compound; the molar ratio of the Schiff base to the reducing agent is controlled to be 1:1.5, the reaction temperature is room temperature, and the reaction time is 0.5 hours; (3) The target product, acetohydroxyacid synthase inhibitor, is prepared by reacting a benzylamine compound with 2-methylsulfonyl-4,6-dimethoxypyrimidine; potassium carbonate or cesium carbonate is used as a base, and 1,4-dioxane is used as a reaction solvent; the molar ratio of the benzylamine compound, 2-methylsulfonyl-4,6-dimethoxypyrimidine and the base is controlled to be 1:1.2:1.2, the reaction temperature is the boiling point of the solvent, and the reaction time is 1 hour; the target product is finally obtained and purified by silica gel chromatography or recrystallization.

4. A herbicidal composition, characterized in that: The method comprises a herbicidally active amount of the acetohydroxyacid synthase inhibitor according to claim 1 and at least one formulation adjuvant.

5. A method for preparing a herbicidally active composition, characterized in that: The method comprises mixing a herbicidally active amount of the acetohydroxyacid synthase inhibitor according to claim 1 and at least one formulation auxiliary.

6. Use of the acetohydroxyacid synthase inhibitor as claimed in claim 1 as an agricultural chemical herbicide, characterized in that: The compound specifically inhibits the activity of acetohydroxy acid synthase or its mutant W574L in plants.

7. The method for using the acetohydroxyacid synthase inhibitor according to claim 1 as an agricultural chemical herbicide to control resistant Leptochloa chinensis, characterized in that: The invention relates to a method for treating a herbicidal amount of an acetohydroxyacid synthase inhibitor on leaves of resistant Leptochloa chinensis at the pre-bud or late-bud stage, and the compound specifically inhibits the activity of acetohydroxyacid synthase or its mutant W574L in the resistant Leptochloa chinensis plant body.

8. The method for using the acetohydroxyacid synthase inhibitor as an agricultural chemical herbicide according to claim 1, characterized in that: The method comprises applying a herbicidal amount of an acetohydroxyacid synthase inhibitor to the leaves of weeds, wherein the compound specifically inhibits the activity of acetohydroxyacid synthase or its mutant W574L in the weed plant body; The weeds are any one of the following: Leptochloa chinensis, Echinochloa crusgalli, Digitaria sanguinea, Amaranthus retroflexus, Goosegrass, Setaria viridis, Poa annua, Chenopodium album, Purslane, Setaria officinalis, Grass of Revolution, Brassica juncea, Polygonum syringae, Cyperus difformis, Sesamum indica, Dalbergia vaginalis, or Cyperus rotundus.

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