Crystalline form of dihydroisoxazole compound and preparation method and application thereof

Abstract

The application relates to the technical field of crystallization, and discloses a crystal form of a dihydroisoxazole compound as well as a preparation method and application of the crystal form. The X-ray powder diffraction pattern of the crystal form S measured at 25 DEG C using Cu-K alpha rays has only one characteristic diffraction peak between 17.5 DEG and 18.5 DEG in the diffraction angle 2 theta. The dihydroisoxazole compound is added into N, N-dimethylacetamide, heated to completely dissolve, a hot liquid is obtained, the hot liquid is poured into a poor solvent, crystals are precipitated, filtration, drying and constant weight are carried out, and the crystal form S of the dihydroisoxazole compound is obtained. The crystal form S of the dihydroisoxazole compound provided by the application has good powder flowability, is convenient for extrusion processing into water dispersible granules, is stable in the crystal form under high temperature, high humidity and light conditions, is not prone to crystal transformation, and maintains stable purity.

Description

Technical Field

[0001] This invention relates to the field of crystallization technology, specifically to a crystal form of a dihydroisoxazole compound, its preparation method, and its application. Background Technology

[0002] The dihydroisoxazole compound represented by Formula I, chemically named [3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylsulfonyl]-4,5-dihydro-5,5-dimethyl-1,2-oxazole], is a broad-spectrum herbicide, showing significant inhibitory effects, particularly against grasses and lambsquarters weeds. It was initially disclosed by Japan's Combinatorial Chemicals Co., Ltd. in patent US7238689, and was developed by converting the benzylbenzene ring into various heterocyclic structures and optimizing the substituents. Compared to commonly available herbicides like metolachlor and acetochlor, the dihydroisoxazole compound represented by Formula I exhibits superior weed control with lower dosage requirements. .

[0003] Polymorphism is a common phenomenon in chemistry. Essentially, it refers to the different crystal structures formed by the same chemical substance due to differences in molecular arrangement or conformation. Substances with different crystal forms often possess different physical, chemical, or biological properties. Screening for pesticide crystal forms with excellent physicochemical properties and high economic benefits can bring significant economic and social benefits.

[0004] The known crystal forms of dihydroisoxazole compounds represented by Formula I are as follows: In patent CN112969697A, Japanese combinatorial chemistry disclosed a macroscopically needle-like or short columnar crystal form obtained by metal-catalyzed oxidation in solvents such as alcohols, nitriles, and carboxylic esters. Its X-ray powder diffraction characteristic peaks are 17.8°, 18.0°, and 19.9°, with 19.9° being the main peak. The needle-like morphology has poor flowability, which is not conducive to the processing of downstream formulations.

[0005] Patent CN114213402A protects the metastable and stable crystal forms of dihydroisoxazole compounds represented by Formula I. The metastable crystal form is needle-shaped, with poor stability, and is prone to moisture absorption, caking, and powdering. The stable crystal form is columnar, with high stability, but it needs to be prepared under high temperature, high pressure, and nitrogen protection, which is complex and costly, making it difficult to scale up for industrial production.

[0006] Therefore, there is an urgent need to develop a new crystal form of the dihydroisoxazole compound shown in Formula I. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems existing in the prior art and provide a crystal form of dihydroisoxazole compounds, their preparation method, and applications.

[0008] To achieve the above objectives, a first aspect of the present invention provides a crystal form S of a dihydroisoxazole compound represented by Formula I, wherein the crystal form S has a single characteristic diffraction peak in the X-ray powder diffraction pattern obtained by measuring Cu-Kα rays at 25°C, with a diffraction angle 2θ between 17.5° and 18.5°. .

[0009] A second aspect of the present invention provides a method for preparing crystal form S of a dihydroisoxazole compound represented by Formula I according to the first aspect, wherein the method comprises the following steps: 1) Add the dihydroisoxazole compound shown in Formula I to N,N-dimethylacetamide and heat until completely dissolved to obtain a hot liquid; 2) Pour the hot liquid from step 1) into a poor solvent to precipitate crystals; 3) After filtration, drying, and constant weight, the crystal form S of the dihydroisoxazole compound shown in Formula I is obtained.

[0010] A third aspect of the present invention provides a crystal form S of a dihydroisoxazole compound of formula I obtained by the preparation method described in the second aspect.

[0011] A fourth aspect of the present invention provides a pesticide composition comprising crystal form S of a dihydroisoxazole compound of formula I as described in the first or third aspect, and at least one pesticide-acceptable excipient.

[0012] The fifth aspect of the present invention provides the use of the crystal form S of the dihydroisoxazole compound represented by Formula I according to the first or third aspect, or the pesticide composition of the fourth aspect, in the preparation of herbicide formulations.

[0013] The beneficial technical effects achieved by the present invention through the above technical solution are as follows: (1) The crystal form S powder of the dihydroisoxazole compound shown in Formula I provided by the present invention has good flowability and is easy to extrude into water-dispersible granules; the crystal form is stable and does not easily transform under high temperature, high humidity and light conditions, and the purity remains stable.

[0014] (2) After the crystal form S provided by the present invention is prepared into water-dispersible granules, it has good wear resistance and low dust, which can reduce dust pollution during operation and improve safety. At the same time, the water-dispersible granules prepared by this crystal form have high suspension rate, small contact angle and large adhesion, which can improve the coverage and contact area of ​​the drug solution and more effectively exert the drug effect. Attached Figure Description

[0015] Figure 1 This is the XRD diffraction pattern of crystal form S prepared in Example 1 of this invention.

[0016] Figure 2 This is a differential scanning calorimetry (DSC) analysis diagram of crystal form S prepared in Example 1 of the present invention.

[0017] Figure 3 This is the thermogravimetric (TGA) diagram of crystal form S prepared in Example 1 of the present invention.

[0018] Figure 4 This is the XRD diffraction pattern of crystal form A prepared in Comparative Example 1 under the same detection conditions. Detailed Implementation

[0019] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0020] The first aspect of this invention provides a crystal form S of a dihydroisoxazole compound represented by Formula I, wherein the crystal form S has a single characteristic diffraction peak in the X-ray powder diffraction pattern obtained by measuring Cu-Kα rays at 25°C, with a diffraction angle 2θ between 17.5° and 18.5°. .

[0021] In some embodiments of the present invention, the crystal form S has diffraction peaks at at least the following diffraction angles 2θ in the X-ray powder diffraction pattern obtained by measuring Cu-Kα rays at 25°C: 5.23±0.2°, 9.76±0.2°, 10.19±0.2°, 14.62±0.2°, 17.95±0.2°, and 19.75±0.2°.

[0022] In some embodiments of the present invention, the X-ray powder diffraction pattern of the crystal form S obtained by measuring Cu-Kα rays at 25°C also includes the following diffraction peaks at diffraction angle 2θ: 20.18±0.2°, 20.63±0.2°, 22.01±0.2°, 22.54±0.2°, 22.92±0.2°, 24.57±0.2°, 25.31±0.2°, 25.65±0.2°, 27.19±0.2°, 28.68±0.2°, 30.06±0.2°, 30.36±0.2°, 31.68±0.2°, 32.60±0.2°, 34.82±0.2°, and 35.65±0.2°.

[0023] In some embodiments of the present invention, the X-ray powder diffraction pattern of the crystal form S, measured using Cu-Kα rays at 25°C, includes the following diffraction peaks at diffraction angles of 2θ: 5.23±0.2°, 9.76±0.2°, 10.19±0.2°, 14.62±0.2°, 17.95±0.2°, 19.75±0.2°, 20.18±0.2°, 20.63±0.2°, 22.01±0.2°, and 22.54±0.2°. 2°, 22.92±0.2°, 24.57±0.2°, 25.31±0.2°, 25.65±0.2°, 27.19±0.2°, 28.68±0.2°, 30.06±0.2°, 30.36±0.2°, 31.68±0.2°, 32.60±0.2°, 34.82±0.2°, 35.65±0.2°, 36.8±0.2°, 37.42±0.2°, 45.10±0.2°.

[0024] In some embodiments of the present invention, the crystal form S has the following characteristics: Figure 1 The X-ray powder diffraction pattern shown.

[0025] In some embodiments of the present invention, the differential scanning calorimetry (DSC) plot of the crystal form S at a heating rate of 10 °C / min shows two characteristic endothermic peaks between 100 and 180 °C.

[0026] In some embodiments of the present invention, the crystal form S has characteristic endothermic peaks at 107±3℃ and 128±3℃.

[0027] In some embodiments of the present invention, the crystal form S has the following characteristics: Figure 2 The differential scanning calorimetry (DSC) graph is shown.

[0028] A second aspect of the present invention provides a method for preparing crystal form S of a dihydroisoxazole compound represented by Formula I according to the first aspect, wherein the method comprises the following steps: 1) Add the dihydroisoxazole compound shown in Formula I to N,N-dimethylacetamide (DMAc) and heat until completely dissolved to obtain a hot liquid; 2) Pour the hot liquid from step 1) into a poor solvent to precipitate crystals; 3) After filtration, drying, and constant weight, the crystal form S of the dihydroisoxazole compound shown in Formula I is obtained.

[0029] In some embodiments of the present invention, in step 1), the mass-to-volume ratio of the dihydroisoxazole compound represented by Formula I to N,N-dimethylacetamide is 1:0.5-10, for example 1:0.5, 1:1, 1:1.5, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, and any value within the range of any two of the above values, preferably 1:1-4, more preferably 1:2, wherein the mass is in g and the volume is in mL.

[0030] In some embodiments of the present invention, in step 1), the heating temperature is 40-100°C, for example 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, and any value within the range of any two of the above values, preferably 50-80°C, and more preferably 70°C.

[0031] In some embodiments of the present invention, in step 2), the unsuitable solvent is selected from at least one of water, methanol, ethanol and isopropanol, preferably water.

[0032] In some embodiments of the present invention, the temperature of the undesirable solvent is 0-35°C, for example 0°C, 5°C, 10°C, 25°C, 30°C, 35°C, and any value within the range of any two of the above values, preferably 5-30°C, and more preferably 25°C.

[0033] A third aspect of the present invention provides a crystal form S of a dihydroisoxazole compound of formula I obtained by the preparation method described in the second aspect.

[0034] A fourth aspect of the present invention provides a pesticide composition comprising crystal form S of a dihydroisoxazole compound of formula I as described in the first or third aspect, and at least one pesticide-acceptable excipient.

[0035] The fifth aspect of the present invention provides the use of the crystal form S of the dihydroisoxazole compound represented by Formula I according to the first or third aspect, or the pesticide composition of the fourth aspect, in the preparation of herbicide formulations.

[0036] The present invention will be described in detail below through embodiments.

[0037] Unless otherwise specified in the following examples and comparative examples, all conditions were performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available products.

[0038] Source of materials: The dihydroisoxazole compounds represented by Formula I are prepared by the following method: Add 400 mL of dichloromethane to a 1000 mL three-necked reaction flask, then add compound II (71.8 g, 0.2 mol, 1 eq). After stirring to dissolve, add sodium tungstate dihydrate (0.32 g, 1.0 mmol, 0.005 eq) and tetrabutylammonium chloride (0.28 g, 1.0 mmol, 0.005 eq) sequentially. Control the system temperature at 35 °C, and begin adding hydrogen peroxide (50.70 g, 27.5%, 0.41 mol, 2.05 eq) dropwise to the system. After the addition is complete, continue stirring at this temperature for 3 h. The reaction is confirmed to be complete by liquid chromatography.

[0039] After the reaction was complete, excess hydrogen peroxide was quenched by adding 10% sodium sulfite solution dropwise until the starch-potassium iodide test paper no longer turned blue. The addition was then stopped. After thorough stirring, the mixture was allowed to stand and separated. The organic phase was washed with water (200 mL × 3 times to remove water-soluble impurities such as sodium tungstate and phase transfer catalyst), followed by solvent removal to obtain 76.73 g of white powder. Analysis confirmed that this white powder was the compound shown in Formula I, with a yield of 98.1%. .

[0040] Example 1 This embodiment illustrates a method for preparing crystal form S of the dihydroisoxazole compound shown in Formula I, including the following steps: 1) Add 10g of the white powder of the dihydroisoxazole compound shown in Formula I to 20mL of DMAc, heat to 70℃, and the solid will completely dissolve to obtain a hot liquid; 2) Pour the hot liquid from step 1) into 300 mL of 25°C water to precipitate crystals; 3) After filtration, drying and constant weight, 9.8g of white crystals were obtained.

[0041] Example 2

[0042] This embodiment illustrates a method for preparing crystal form S of the dihydroisoxazole compound shown in Formula I, including the following steps: 1) Add 10g of the white powder of the dihydroisoxazole compound shown in Formula I to 10mL of DMAc, heat to 60℃, and the solid will completely dissolve to obtain a hot liquid; 2) Pour the hot liquid from step 1) into 200 mL of methanol at 10 °C to precipitate crystals; 3) After filtration, drying and constant weight, 9.9g of white crystals were obtained.

[0043] Example 3

[0044] This embodiment illustrates a method for preparing crystal form S of the dihydroisoxazole compound shown in Formula I, including the following steps: 1) Add 10g of the white powder of the dihydroisoxazole compound shown in Formula I to 15mL of DMAc, heat to 80℃, and the solid will completely dissolve to obtain a hot liquid; 2) Pour the hot liquid from step 1) into 100 mL of isopropanol at 10°C, and crystals will precipitate. 3) After filtration, drying and constant weight, 9.7g of white crystals were obtained.

[0045] Example 4

[0046] This embodiment illustrates a method for preparing crystal form S of the dihydroisoxazole compound shown in Formula I, including the following steps: 1) Add 10g of the white powder of the dihydroisoxazole compound shown in Formula I to 30mL of DMAc, heat to 40℃, and the solid will completely dissolve to obtain a hot liquid; 2) Pour the hot liquid from step 1) into 300 mL of room temperature isopropanol to precipitate crystals; 3) After filtration, drying and constant weight, 9.8g of white crystals were obtained.

[0047] Example 5

[0048] This embodiment illustrates a method for preparing crystal form S of the dihydroisoxazole compound shown in Formula I, including the following steps: 1) Add 10g of the white powder of the dihydroisoxazole compound shown in Formula I to 40mL of DMAc, heat to 40℃, and the solid will completely dissolve to obtain a hot liquid; 2) Pour the hot liquid from step 1) into 300 mL of water at 5°C to precipitate crystals; 3) After filtration, drying and constant weight, 9.8g of white crystals were obtained.

[0049] Example 6

[0050] This embodiment illustrates a method for preparing crystal form S of the dihydroisoxazole compound shown in Formula I, including the following steps: 1) Add 10g of the white powder of the dihydroisoxazole compound shown in Formula I to 15mL of DMAc, heat to 60℃, and the solid will completely dissolve to obtain a hot liquid; 2) Pour the hot liquid from step 1) into 150 mL of methanol at 5 °C to precipitate crystals; 3) After filtration, drying and constant weight, 9.9g of white crystals were obtained.

[0051] Comparative Example 1 This comparative example illustrates the method for preparing crystal form A of the dihydroisoxazole compound shown in Formula I, including the following steps: 1) Add 10g of the white powder of the dihydroisoxazole compound shown in Formula I to 20mL of DMAc, heat to 50℃, and the solid will completely dissolve to obtain a hot liquid; 2) Cool the hot liquid from step 1) at 4°C to allow crystals to precipitate; 3) After filtration, drying and constant weight, 9.1g of white crystals were obtained, which were denoted as crystal A.

[0052] Test Example 1 (1) The white crystals obtained in Example 1 were subjected to X-ray powder diffraction pattern analysis under the following conditions: Rigaku (Miniflex 600 type); copper target; tube voltage 40 kV, tube current 15 mA, scanning angle range 3°-50°, scanning speed 20° / min, scanning step size 0.01°; its XRD pattern is shown below. Figure 1 As shown, the characteristic peaks are shown in Table 1. Figure 1 Therefore, the crystal obtained in Example 1 is the crystal form S of the present invention.

[0053] Table 1 ; Using the same XRD detection conditions as in Example 1, the white crystals obtained in Examples 2-6 were subjected to XRD pattern detection, confirming that they were all crystal form S of the present invention.

[0054] Furthermore, using the same XRD detection conditions as in Example 1, the crystal A obtained in Comparative Example 1 was subjected to XRD pattern detection, confirming that the crystal form A of the comparative example is consistent with the crystal form disclosed in CN112969697A. Figure 4 As shown.

[0055] (2) The white crystals obtained in Example 1 were subjected to differential scanning calorimetry (DSC) analysis under the following conditions: TA (DSC25 type) instrument, with indium as the temperature / thermal calibrator, under nitrogen protection, with a heating rate of 10℃ / min, and a temperature range of 40-150℃ (313.15-423.15K); the DSC analysis chromatogram is shown below. Figure 2 As shown. From Figure 2 It can be seen that in the differential scanning calorimetry (DSC) graph of crystal form S at a heating rate of 10℃ / min, there are two characteristic endothermic peaks between 100-180℃, located at 107±3℃ and 128±3℃ respectively. The white crystals obtained in Examples 2-6 showed the same detection results under the same detection conditions.

[0056] (3) The white crystals obtained in Example 1 were subjected to thermogravimetric analysis (TGA) under the following conditions: TA (TGA55) instrument, using nickel as the temperature calibrator, under nitrogen atmosphere, with a heating rate of 10℃ / min and a temperature range of 20-290℃ (293.15-563.15K); the TGA graph is shown below. Figure 3 As shown. The white crystals obtained in Examples 2-6 showed the same detection results under the same detection conditions.

[0057] Test Example 2: Study on Crystal Form Stability (1) High temperature stability The samples were placed in an environment of 50℃±2.0℃ for 30 days, and samples were taken and tested on day 0, day 5, day 10 and day 30. The results are shown in Table 2.

[0058] Table 2 ; (2) Study on high humidity stability The samples were placed in a constant temperature and humidity chamber at 25℃ and 90%±5% for 30 days. Samples were taken and tested on day 0, day 5, day 10 and day 30. The results are shown in Table 3.

[0059] Table 3 ; (3) Study on light stability The samples were placed at 4500±500 lx for 30 days, and samples were taken and tested on day 0, day 5, day 10 and day 30. The results are shown in Table 4.

[0060] Table 4 ; As can be seen from the results in Tables 2-4, the crystal form S of the dihydroisoxazole compound of Formula I prepared in Examples 1-2 of the present invention maintains stable purity under high temperature, high humidity and light conditions, which is a significant advantage compared with the existing crystal forms.

[0061] Test Example 3: Flowability Measurement The angles of repose of the samples obtained in Examples 1-6 of the present invention and the sample obtained in Comparative Example 1 were measured respectively, and the results are shown in Table 5.

[0062] Table 5 ; As can be seen from the results in Table 5, the crystal form S of the dihydroisoxazole compound of Formula I prepared in this invention has better flowability than existing crystal forms, making it easier to extrude and process into water-dispersible granules.

[0063] Test Example 4: Formulation Performance Test Water-dispersible granules were prepared using the white powder obtained in Example 1 or Comparative Example 1 as the active ingredient: 85% active ingredient, 5% polycarboxylate dispersant GY-D800, 2% alkyl naphthalene sulfonate wetting agent GEROPON L-WET / R, and 100% naphthalene sulfonate dispersant SUPRAGIL MNS / 90. The components were weighed according to the above proportions and mixed evenly. The mixture was then pulverized using an air jet mill until the particle size reached ≥98% passing through a 75μm wet sieve. After obtaining the qualified powder, 10% water was added, kneaded evenly, and then granulated using a laboratory extrusion granulator. The granules were then dried using a laboratory fluidized bed dryer at 45°C for 30 minutes, with the moisture content controlled to ≤2.0%. The water-dispersible granule samples prepared using the crystals from Example 1 and the Comparative Example as the active ingredient were designated WDG1 and WDG2, respectively.

[0064] (1) Based on the methods for determining the abrasion resistance of water-dispersible granules of pesticides (GB / T 33031-2016), the methods for determining the dust of granular pesticides (GB / T 30360-2013), the methods for determining the suspension rate of pesticides (GB / T 14825-2023), the methods for determining the dispersibility of pesticides (GB / T 32775-2016), the methods for determining the persistent foaming property of pesticides (GB / T 28137-2011), and the methods for determining the moisture content of pesticides (GB / T 1600-2021), the two samples were tested for abrasion resistance, dust content, moisture content, suspension rate, dispersibility, and persistent foaming property. The results are shown in Table 6.

[0065] Table 6 ; The results above show that, compared with the water-dispersible granules WDG2 prepared from crystal form A, the water-dispersible granules WDG1 prepared from crystal form S produce significantly less dust, have stronger wear resistance, and are superior in reducing dust pollution and improving safety during operation.

[0066] (2) After diluting WDG1 and WDG2 with tap water by 1000 times, the static surface tension, contact angle (green ivy leaf) and adhesion force (green ivy leaf) were tested using a fully automatic adhesion tester SCI300M. The results are shown in Table 7.

[0067] Table 7 ; The results above show that, at the same dilution factor, compared with the water-dispersible granules WDG2 prepared from crystal form A, the water-dispersible granules WDG1 prepared from crystal form S have lower surface tension and smaller contact angle, indicating that they are more likely to wet the target surface and form a uniform drug film, which helps to improve coverage. At the same time, the strong adhesion can reduce the loss of drug solution caused by rain or environmental factors, prolong the contact time between the drug and the target, thus exhibiting more stable and better efficacy.

[0068] (3) Field efficacy trial Test reagents: WDG1 and WDG2.

[0069] Target weeds: Alopecurus aequalis, Broccoli, Lorrae polyflora, Desmodium styracifolium, and Lamb's quarters (all common annual weeds in wheat fields).

[0070] Seed source: Watching the wheatgrass ( Alopecurus aequalis (), collected from Shandong Academy of Agricultural Sciences; Brome ( Bromus japonicus (The samples were collected from Liwang Village, Dianzi Town, Boxing County, Binzhou City, Shandong Province.) Multiflora ryegrass ( Lolium multiflorum (The samples were collected from Xingken Village, Sheyang County, Yancheng City, Jiangsu Province.) Sow thistle ( Descurainia sophia (The samples were collected from Dawang Village, Dianzi Town, Boxing County, Binzhou City, Shandong Province.) quinoa ( Chenopodium album (The sample was collected from Caoying Village, Caowang Town, Boxing County, Binzhou City, Shandong Province.)

[0071] Experimental location: Greenhouse at the agricultural cooperative base in Boxing County, Binzhou City, Shandong Province.

[0072] Test method: Fill plastic pots (7×7×10cm) with a mixture of substrate and field soil (1:2). Select plump weed seeds and sow 20 seeds each of *Alopecurus aequalis*, *Brassica rapa*, *Lolium floribunda*, *Lactuca indica*, and *Chenopodium album*. Cover with a layer of fine soil, water, and maintain a moisture level. Place the pots in a greenhouse with natural light. The greenhouse temperature is approximately 25°C during the day and 15°C at night. 24 hours after sowing, apply a soil sealant using a soil spray method according to the dosage settings described above. A control group with an equal amount of water is included. Each treatment consists of 30 pots, and the treatment is repeated four times. Spraying was performed using a bioassay spray tower (model: NJ22-3WPSH-500D) purchased from Beijing Haifuda Technology Co., Ltd. The rotation speed was 6 r / min, the spray height was 25 cm, the effective spray width was 30 cm, and the flow rate was 210 mL / min. Each treatment (30 pots) received 40 mL of pesticide solution (Note: Normal field soil spraying uses 30-45 L of water per acre). After application, cultivation continued.

[0073] Weed emergence rate was observed and recorded on days 2, 4, and 6 after application of the herbicide. Weed height (height of the above-ground portion of the weed) was measured on days 10 and 20 in each experimental case, and the height inhibition rate was calculated. The results for each experimental case are shown in Table 8.

[0074] Table 8 ; Data statistics: Germination rate = (Number of germinations / Number of seeds) × 100% Plant height inhibition rate: Plant height inhibition rate (%) = (average plant height of control group - average plant height of treatment group) / average plant height of control group × 100% The emergence rate and plant height inhibition rate of weeds in each experimental case are shown in Table 9.

[0075] Table 9 ; Table 9 shows that using 85% sulfonylpyrazole WDG1 (crystal form S) as a top dressing herbicide is more effective than using 85% sulfonylpyrazole WDG2 (crystal form A). Compared with WDG2, the emergence rates of *Alopecurus aequalis*, *Oryza sativa*, *Lolium floribunda*, *Desmodium styracifolium*, and *Chenopodium album* were generally lower on days 2, 4, and 6 after applying WDG1; the plant height inhibition rates of *Alopecurus aequalis*, *Oryza sativa*, *Lolium floribunda*, *Desmodium styracifolium*, and *Chenopodium album* were generally lower on days 10 and 20.

[0076] This demonstrates that 85% sulfonylpyrazole WDG1 (crystal form S) has a faster and longer-lasting weed control effect when applied to the ground.

[0077] (4) Field efficacy trial II Experimental objective: To conduct a comparative experiment on the efficacy of different crystal forms of sulfopyrazole formulations in controlling weeds under simulated precipitation conditions, and to compare the effects of the two formulations under precipitation conditions, so as to provide a theoretical basis for further field application.

[0078] Experimental materials: The experimental agent, target pests, and experimental location are the same as above. Test method: Fill plastic pots (7×7×10cm) with a mixture of substrate and field soil (1:2). Select plump weed seeds and sow 20 seeds each of *Alopecurus aequalis*, *Brassica rapa*, *Lolium floribunda*, *Lactuca indica*, and *Chenopodium album*. Cover with a layer of fine soil, water, and maintain a moisture level. Place the pots in a greenhouse with natural light. The greenhouse temperature is approximately 25°C during the day and 15°C at night. 24 hours after sowing, apply a soil sealant using a soil spray method according to the dosage settings described above. A control group with an equal amount of water is included. Each treatment consists of 30 pots, and the treatment is repeated four times. Spraying was performed using a bioassay spray tower (model: NJ22-3WPSH-500D) purchased from Beijing Haifuda Technology Co., Ltd. The rotation speed was 6 r / min, the spray height was 25 cm, the effective spray width was 30 cm, and the flow rate was 210 mL / min. Each treatment (30 pots) received 40 mL of pesticide solution (Note: Normal field soil spraying uses 30-45 L of water per acre). After application, cultivation continued.

[0079] Rainfall conditions: On the second day after application of the pesticide, simulated rainfall was applied to all potted plants with a fine mist spray for 0.5 hours at a nozzle flow rate of 300 mL / min. After spraying, the plants were continued to be cultivated and observed in the greenhouse. Later, they were managed under normal conditions, including the same temperature conditions as above.

[0080] The test reagents and dosages are the same as in Table 8.

[0081] Data statistics: Data on weed emergence rate 7 days after pesticide application: Germination rate = (Number of germinations / Number of seeds) × 100% The weed emergence rate statistics for each experimental case are shown in Table 10.

[0082] Table 10 ; As shown in Table 10, under simulated rainfall conditions, for the five weeds mentioned above, the emergence rate of 85% sulfonylpyrazole WDG2 (crystal form A) was 10-15% higher than that of 85% sulfonylpyrazole WDG1 (crystal form S). 85% sulfonylpyrazole WDG1 (crystal form S) showed better weed control but a lower emergence rate. 85% sulfonylpyrazole WDG1 (crystal form S) maintained better efficacy and exhibited better resistance to rain washout under rainfall conditions.

[0083] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A crystal form S of a dihydroisoxazole compound represented by Formula I, characterized in that, The X-ray powder diffraction pattern of crystal form S, measured using Cu-Kα rays at 25°C, shows a single characteristic diffraction peak between 17.5° and 18.5° at a diffraction angle 2θ. Formula I; Wherein, the crystal form S, in the X-ray powder diffraction pattern obtained by measuring Cu-Kα rays at 25°C, has diffraction peaks at at least the following diffraction angles 2θ: 5.23±0.2°, 9.76±0.2°, 10.19±0.2°, 14.62±0.2°, 17.95±0.2°, 19.75±0.2°; The X-ray powder diffraction pattern of crystal form S, measured using Cu-Kα rays at 25°C, also includes the following diffraction peaks at diffraction angle 2θ: 20.18±0.2°, 20.63±0.2°, 22.01±0.2°, 22.54±0.2°, 22.92±0.2°, 24.57±0.2°, 25.31±0.2°, 25.65±0.2°, 27.19±0.2°, 28.68±0.2°, 30.06±0.2°, 30.36±0.2°, 31.68±0.2°, 32.60±0.2°, 34.82±0.2°, and 35.65±0.2°.

2. The crystal form S according to claim 1, characterized in that, In the differential scanning calorimetry (DSC) plot of the crystal form S at a heating rate of 10 °C / min, there are two characteristic endothermic peaks between 100 and 180 °C.

3. A method for preparing crystal form S of the dihydroisoxazole compound represented by formula I according to claim 1 or 2, characterized in that, The method includes the following steps: 1) Add the dihydroisoxazole compound shown in Formula I to N,N-dimethylacetamide and heat until completely dissolved to obtain a hot liquid; 2) Pour the hot liquid from step 1) into a poor solvent to precipitate crystals; 3) After filtration, drying, and constant weight, the crystal form S of the dihydroisoxazole compound shown in Formula I is obtained.

4. The preparation method according to claim 3, characterized in that, In step 1), the mass-to-volume ratio of the dihydroisoxazole compound represented by formula I to N,N-dimethylacetamide is 1:0.5-10, where the mass is in g and the volume is in mL.

5. The preparation method according to claim 3 or 4, characterized in that, In step 2), the unsuitable solvent is selected from at least one of water, methanol, ethanol and isopropanol.

6. A crystal form S of a dihydroisoxazole compound represented by Formula I, characterized in that, The crystal form S is obtained by the preparation method according to any one of claims 3-5.

7. A pesticide composition, characterized in that, It includes the crystal form S of the dihydroisoxazole compound of formula I as described in any one of claims 1-2 and 6, and at least one pesticide-acceptable excipient.

8. The application of crystal form S of the dihydroisoxazole compound of formula I according to any one of claims 1-2 and 6, or the pesticide composition according to claim 7, characterized in that, The application is in the preparation of herbicide formulations.

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