Crystal form of dihydroisoxazole compound and preparation method and application thereof

Abstract

The invention 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. In an X-ray powder diffraction pattern obtained by measuring the crystal form S by using Cu-K alpha rays at 25 DEG C, only one characteristic diffraction peak exists when a diffraction angle 2 theta is between 17.5 degrees and 18.5 degrees. The preparation method comprises the following steps: adding a dihydroisoxazole compound into N, N-dimethylacetamide, and heating until the dihydroisoxazole compound is completely dissolved to obtain hot liquid; pouring the hot liquid into a poor solvent, and separating out crystals; and filtering, drying and keeping the weight constant to obtain the crystal form S of the dihydroisoxazole compound. The crystal form S powder of the dihydroisoxazole compound provided by the invention is good in flowability and convenient to extrude and process into water dispersible granules; the crystal form is stable under the conditions of high temperature, high humidity and illumination, crystal transformation is not easy to occur, and the purity is kept stable.

Description

Technical Field

[0001] The present invention relates to the field of crystallization technology, and in particular to a crystal form of a dihydroisoxazole compound, a preparation method and an application thereof. Background Art

[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, particularly effective against grass and Chenopodiaceae weeds. Originally disclosed by Kumihiko Chemical Co., Ltd. in patent US7238689, it was developed by converting the benzylbenzene ring into various heterocyclic structures and optimizing the substituents. Compared to the commonly used isopropylamine and acetochlor herbicides on the market, the dihydroisoxazole compound represented by Formula I exhibits superior herbicidal efficacy and requires a lower dosage. .

[0003] Polymorphism is a common phenomenon in chemistry. Essentially, it occurs when the same chemical substance forms different crystal structures due to differences in molecular arrangement or conformation. These different crystal forms often exhibit distinct physical, chemical, or biological properties. Identifying pesticide crystal forms with superior physical and chemical properties and high economic benefits can bring significant economic and social benefits.

[0004] The currently known crystalline forms of the dihydroisoxazole compounds represented by formula I are as follows: In patent CN112969697A, Japan Combinatorial Chemistry disclosed a crystal form with a macroscopic morphology of needles or short columns, which was obtained by using metal-catalyzed oxidation in alcohol, nitrile, and carboxylic acid ester solvents. Its X-ray powder diffraction characteristic peaks are 17.8°, 18.0°, and 19.9°, of which 19.9° is the main peak. The needle-shaped morphology has poor fluidity, which is not conducive to the processing operation of downstream preparations.

[0005] Patent CN114213402A protects the metastable and stable crystal forms of the dihydroisoxazole compound represented by Formula I, respectively. The metastable crystal form is needle-shaped, has poor stability, and is prone to moisture absorption, hardening, and powdering. The stable crystal form is columnar and has high stability, but requires preparation under high temperature, high pressure, and nitrogen protection. The process is complex and costly, making it difficult to industrialize on a large scale.

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

[0007] The purpose of the present invention is to overcome the problems existing in the prior art and provide a crystalline form of a dihydroisoxazole compound and a preparation method and application thereof.

[0008] To achieve the above objectives, the present invention provides, in a first aspect, a crystalline form S of a dihydroisoxazole compound represented by formula I, wherein the crystalline form S has an X-ray powder diffraction pattern measured at 25°C using Cu-Kα radiation, and has only one characteristic diffraction peak at a diffraction angle 2θ between 17.5° and 18.5°. .

[0009] The second aspect of the present invention provides a method for preparing the crystalline form S of the dihydroisoxazole compound represented by formula I according to the first aspect, wherein the method comprises the following steps: 1) adding the dihydroisoxazole compound represented by formula I to N,N-dimethylacetamide and heating until completely dissolved to obtain a hot liquid; 2) Pour the hot liquid from step 1) into a poor solvent to precipitate crystals; 3) Filtering, drying, and maintaining constant weight to obtain the crystalline form S of the dihydroisoxazole compound represented by Formula I.

[0010] The third aspect of the present invention provides a crystalline form S of a dihydroisoxazole compound represented by formula I obtained according to the preparation method described in the second aspect.

[0011] The fourth aspect of the present invention provides a pesticide composition comprising the crystalline form S of the dihydroisoxazole compound represented by formula I according to the first aspect or the third aspect, and at least one pesticide-acceptable excipient.

[0012] The fifth aspect of the present invention provides use of the crystalline form S of the dihydroisoxazole compound represented by formula I according to the first aspect or the third aspect or the pesticide composition according to the fourth aspect in preparing a herbicide formulation.

[0013] Through the above technical solution, the beneficial technical effects achieved by the present invention are as follows: (1) The crystalline form S powder of the dihydroisoxazole compound represented by formula I provided by the present invention has good fluidity and is easy to be extruded into water-dispersible granules. The crystalline form is stable and not easily transformed 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 the operation process and improve safety; at the same time, the water-dispersible granules prepared by this crystal form have a high suspension rate, a small contact angle, and a large adhesion force, which can increase the coverage rate and contact area of the drug solution and more effectively exert the drug efficacy. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0018] Figure 4 This is the XRD diffraction pattern of Form A prepared in Comparative Example 1 under the same detection conditions. DETAILED DESCRIPTION

[0019] The endpoints of the ranges and any values 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 endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0020] In a first aspect, the present invention provides a crystalline form S of a dihydroisoxazole compound represented by formula I, wherein the crystalline form S has an X-ray powder diffraction pattern measured at 25°C using Cu-Kα radiation, and has a single characteristic diffraction peak at a diffraction angle 2θ between 17.5° and 18.5°. .

[0021] In some embodiments of the present invention, the crystalline form S has a diffraction peak at least at the following diffraction angles 2θ in the X-ray powder diffraction pattern measured at 25°C using Cu-Kα rays: 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 crystalline form S measured at 25°C using Cu-Kα rays further includes the following diffraction peaks at diffraction angles 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 crystalline form S measured at 25°C using Cu-Kα radiation includes the following diffraction peaks at 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°, 20.18±0.2°, 20.63±0.2°, 22.01±0.2°, 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°, and 45.10±0.2°.

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

[0025] In some embodiments of the present invention, the differential scanning calorimetry analysis diagram of the crystalline form S at a heating rate of 10°C / min has two characteristic endothermic peaks between 100°C and 180°C.

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

[0027] In some embodiments of the present invention, the crystalline form S has the following Figure 2 The differential scanning calorimetry analysis diagram is shown.

[0028] The second aspect of the present invention provides a method for preparing the crystalline form S of the dihydroisoxazole compound represented by formula I according to the first aspect, wherein the method comprises the following steps: 1) adding the dihydroisoxazole compound represented by formula I to N,N-dimethylacetamide (DMAc) and heating until completely dissolved to obtain a hot liquid; 2) Pour the hot liquid from step 1) into a poor solvent to precipitate crystals; 3) Filtering, drying, and maintaining constant weight to obtain the crystalline form S of the dihydroisoxazole compound represented by Formula I.

[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 consisting of any two of the above values, preferably 1:1-4, more preferably 1:2, wherein the mass is measured in g and the volume is measured 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, more preferably 70°C.

[0031] In some embodiments of the present invention, in step 2), the poor 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 poor 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] The third aspect of the present invention provides a crystalline form S of a dihydroisoxazole compound represented by formula I obtained according to the preparation method described in the second aspect.

[0034] The fourth aspect of the present invention provides a pesticide composition comprising the crystalline form S of the dihydroisoxazole compound represented by formula I according to the first aspect or the third aspect, and at least one pesticide-acceptable excipient.

[0035] The fifth aspect of the present invention provides use of the crystalline form S of the dihydroisoxazole compound represented by formula I according to the first aspect or the third aspect or the pesticide composition according to the fourth aspect in preparing a herbicide formulation.

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

[0037] In the following examples and comparative examples, if no specific conditions are specified, the experiments were carried out under conventional conditions or those recommended by the manufacturer. All reagents and instruments used, if no manufacturer is specified, are commercially available conventional products.

[0038] Sources: The dihydroisoxazole compound represented by formula I is prepared by the following method: To a 1000mL three-necked reaction flask, 400mL of dichloromethane was added, followed by the addition of the compound of formula II (71.8g, 0.2mol, 1eq). After stirring and dissolving, sodium tungstate dihydrate (0.32g, 1.0mmol, 0.005eq) and tetrabutylammonium chloride (0.28g, 1.0mmol, 0.005eq) were added in sequence. The system temperature was controlled at 35°C, and hydrogen peroxide (50.70g, 27.5%, 0.41mol, 2.05eq) was added dropwise. After the addition was complete, stirring was continued at the same temperature for 3h. The reaction was detected to be complete by liquid chromatography.

[0039] After the reaction is complete, 10% sodium sulfite solution is added dropwise to the system to quench the excess hydrogen peroxide. The addition is stopped when the starch potassium iodide test paper does not turn blue. After thorough stirring, the mixture is allowed to stand for separation. The organic phase is washed with water (200 mL x 3 to remove water-soluble impurities such as sodium tungstate and phase transfer catalyst), and then the organic phase is desolventized to obtain 76.73 g of white powder. After testing, the white powder is the compound of Formula I, with a yield of 98.1%. .

[0040] Example 1 This example is used to illustrate the preparation method of the crystalline form S of the dihydroisoxazole compound represented by Formula I, which comprises the following steps: 1) Add 10 g of the white powder of the dihydroisoxazole compound of formula I to 20 mL of DMAc and heat to 70°C until the solid completely dissolves to obtain a hot liquid; 2) Pour the hot liquid from step 1) into 300 mL of 25°C water to precipitate crystals; 3) Filter, dry, and weigh to obtain 9.8 g of white crystals.

[0041] Example 2

[0042] This example is used to illustrate the preparation method of the crystalline form S of the dihydroisoxazole compound represented by Formula I, which comprises the following steps: 1) Add 10 g of white powder of the dihydroisoxazole compound of formula I to 10 mL of DMAc and heat to 60°C until the solid completely dissolves to obtain a hot liquid; 2) Pour the hot liquid from step 1) into 200 mL of 10°C methanol to precipitate crystals; 3) Filter, dry, and weigh to obtain 9.9 g of white crystals.

[0043] Example 3

[0044] This example is used to illustrate the preparation method of the crystalline form S of the dihydroisoxazole compound represented by Formula I, which comprises the following steps: 1) Add 10 g of white powder of the dihydroisoxazole compound of formula I to 15 mL of DMAc and heat to 80°C until the solid completely dissolves to obtain a hot liquid; 2) Pour the hot liquid from step 1) into 100 mL of 10°C isopropanol to precipitate crystals; 3) Filter, dry, and weigh to obtain 9.7 g of white crystals.

[0045] Example 4

[0046] This example is used to illustrate the preparation method of the crystalline form S of the dihydroisoxazole compound represented by Formula I, which comprises the following steps: 1) Add 10 g of white powder of the dihydroisoxazole compound of formula I to 30 mL of DMAc and heat to 40°C until the solid completely dissolves to obtain a hot liquid; 2) Pour the hot liquid from step 1) into 300 mL of room temperature isopropanol to precipitate crystals; 3) Filter, dry, and weigh to obtain 9.8 g of white crystals.

[0047] Example 5

[0048] This example is used to illustrate the preparation method of the crystalline form S of the dihydroisoxazole compound represented by Formula I, which comprises the following steps: 1) Add 10 g of white powder of the dihydroisoxazole compound of formula I to 40 mL of DMAc and heat to 40°C until the solid completely dissolves to obtain a hot liquid; 2) Pour the hot liquid from step 1) into 300 mL of 5°C water to precipitate crystals; 3) Filter, dry, and weigh to obtain 9.8 g of white crystals.

[0049] Example 6

[0050] This example is used to illustrate the preparation method of the crystalline form S of the dihydroisoxazole compound represented by Formula I, which comprises the following steps: 1) Add 10 g of white powder of the dihydroisoxazole compound of formula I to 15 mL of DMAc and heat to 60°C until the solid completely dissolves to obtain a hot liquid; 2) Pour the hot liquid from step 1) into 150 mL of 5°C methanol to precipitate crystals; 3) Filter, dry, and weigh to obtain 9.9 g of white crystals.

[0051] Comparative Example 1 This comparative example is used to illustrate the preparation method of the crystalline form A of the dihydroisoxazole compound represented by Formula I, which comprises the following steps: 1) Add 10 g of white powder of the dihydroisoxazole compound of formula I to 20 mL of DMAc and heat to 50°C until the solid completely dissolves to obtain a hot liquid; 2) Cooling the hot liquid from step 1) at 4°C to precipitate crystals; 3) Filter, dry, and weigh to constant value to obtain 9.1 g of white crystals, which are recorded as crystals A.

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

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

[0054] In addition, the same XRD detection conditions as in Example 1 were used to detect the XRD pattern of the crystal A obtained in Comparative Example 1, confirming that the crystal form A of the comparative example was consistent with the crystal form disclosed in CN112969697A, as shown in FIG. Figure 4 shown.

[0055] (2) The white crystals obtained in Example 1 were subjected to differential scanning calorimetry (DSC) under the following conditions: TA (DSC25) instrument, indium as the temperature / heat calibrant, under nitrogen protection, heating rate of 10°C / min, temperature range of 40-150°C (313.15-423.15K); the DSC analysis diagram is shown as follows: Figure 2 As shown. Figure 2 It can be seen that the differential scanning calorimetry analysis of Form S at a heating rate of 10°C / min shows two characteristic endothermic peaks between 100°C and 180°C, at 107±3°C and 128±3°C, respectively. The white crystals obtained in Examples 2-6 had the same test results under the same test conditions.

[0056] (3) The white crystals obtained in Example 1 were subjected to thermogravimetric (TGA) analysis under the following conditions: a TA (TGA55) instrument, nickel as the temperature calibrant, a nitrogen atmosphere, a heating rate of 10°C / min, a temperature range of 20-290°C (293.15-563.15K); the TGA diagram is shown in FIG. Figure 3 The white crystals obtained in Examples 2-6 had the same test results under the same test conditions.

[0057] Test Example 2: Crystal Stability Study (1) High temperature stability The samples were placed at 50°C ± 2.0°C for 30 days. Samples were taken for testing on the 0th, 5th, 10th, and 30th days. The results are shown in Table 2.

[0058] Table 2 ; (2) High humidity stability study The samples were placed in a constant temperature and humidity chamber at 25°C and 90%±5% for 30 days. Samples were taken for testing on the 0th, 5th, 10th, and 30th days. The results are shown in Table 3.

[0059] Table 3 ; (3) Light stability study The samples were placed at 4500±500lx for 30 days, and samples were taken for testing on the 0th, 5th, 10th and 30th days. The results are shown in Table 4.

[0060] Table 4 ; It can be seen from the results in Tables 2-4 that the crystal form S of the dihydroisoxazole compound represented by Formula I prepared in Example 1-2 of the present invention has a significant advantage over the existing crystal forms in that its purity remains stable under high temperature, high humidity and light conditions.

[0061] Test Example 3: Fluidity 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. The results are shown in Table 5.

[0062] Table 5 ; From the results in Table 5, it can be seen that the crystal form S of the dihydroisoxazole compound represented by Formula I prepared in the present invention has better fluidity than the existing crystal forms and is easy to be extruded into water-dispersible granules.

[0063] Test Example 4: Preparation 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% alkylnaphthalenesulfonate wetting agent GEROPON L-WET / R, and 100% naphthalenesulfonate dispersant SUPRAGIL MNS / 90. The components were weighed and mixed uniformly according to the above proportions, and then pulverized in a jet mill to a particle size of 75 μm with a wet sieve pass rate of ≥98%. The qualified powder was then added with 10% water, kneaded uniformly, and granulated in a laboratory extrusion granulator. The granules were then dried in a laboratory fluidized bed dryer at 45°C for 30 minutes to control the moisture content to ≤2.0%. The water-dispersible granule samples prepared using the crystals from Example 1 and Comparative Example as the active ingredients were designated WDG1 and WDG2, respectively.

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

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

[0066] (2) After WDG1 and WDG2 were diluted 1000 times with tap water, the static surface tension, contact angle (on the leaves of Pothos radish) and adhesion (on the leaves of Pothos radish) were tested using the fully automatic adhesion tester SCI300M. The results are shown in Table 7.

[0067] Table 7 ; The above results show that, at the same dilution multiple, 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 contact angle of the drug solution, indicating that it is easier to wet the target surface and form a uniform drug film, which helps to improve the coverage rate; at the same time, the adhesion is strong, which can reduce the loss of drug solution caused by rain erosion or environmental factors, and prolong the contact time between the drug and the target, so that it can better demonstrate stable and good drug efficacy.

[0068] (3) Field efficacy test 1 Test agents: WDG1 and WDG2.

[0069] Targets of prevention and control: Alopecurus mume, Bromus striata, Lolium multiflorum, Artemisia selengensis, and Chenopodium album (all common annual weeds in wheat fields).

[0070] Seed source: See the wheatgrass Alopecurus aequalis ), collected from Shandong Academy of Agricultural Sciences; Brome ( Bromus japonicus ), collected from Liwang Village, Dianzi Town, Boxing County, Binzhou City, Shandong Province; Lolium multiflorum ( Lolium multiflorum ), collected from Xingken Village, Sheyang County, Yancheng City, Jiangsu Province; Artemisia selengensis Descurainia sophia ), collected from Dawang Village, Dianzi Town, Boxing County, Binzhou City, Shandong Province; Quinoa ( Chenopodium album ), collected from Caoying Village, Caowang Town, Boxing County, Binzhou City, Shandong Province.

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

[0072] Test method: Fill plastic pots (7 × 7 × 10 cm) with a soil mixture (a 1:2 ratio of substrate nutrient soil to field soil). Select plump weed seeds and sow 20 seeds per pot of Alopecurus striata, Bromus gracilis, Lolium multiflorum, Artemisia selengensis, and Chenopodium album. Cover with a layer of fine soil and water to maintain a moisture layer. After sowing, cultivate in a lighted greenhouse. The greenhouse temperature is approximately 25°C during the day and 15°C at night, under natural light conditions. 24 hours after sowing, seal the soil of the weed pots with a soil spray according to the above-sprayed dosage. An equal amount of water is used as a control. Each treatment consists of 30 pots, replicated four times. Spraying was performed using a bioassay spray tower (model: NJ22-3WPSH-500D) purchased from Beijing Haifuda Technology Co., Ltd., with a rotation speed of 6 rpm, a spray height of 25 cm, an effective spray width of 30 cm, and a flow rate of 210 mL / min. The spray volume for each treatment (30 pots) was 40 mL (Note: Normal field soil spray application rate is 30-45 L of water / mu). Cultivation was continued after application.

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

[0074] Table 8 ; 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 weed emergence rate and plant height inhibition rate of each test case are shown in Table 9.

[0075] Table 9 ; Table 9 shows that 85% sulfonepyraclostrobin WDG1 (Crystal Form S) was more effective as a herbicide than 85% sulfonepyraclostrobin WDG2 (Crystal Form A). Application of WDG1 resulted in lower seedling emergence rates for Alopecurus australis, Bromus striata, Lolium multiflorum, Artemisia selengensis, and Chenopodium album on days 2, 4, and 6 compared to WDG2. Plant height inhibition rates for Alopecurus australis, Bromus striata, Lolium multiflorum, Artemisia selengensis, and Chenopodium album were also lower on days 10 and 20.

[0076] It can be seen that 85% sulfonepyraclostrobin WDG1 (crystal form S) has a faster sealing effect and longer-lasting weed control.

[0077] (4) Field efficacy test 2 Purpose of the experiment: To conduct a comparative test on the weed control efficacy of different crystalline sulfonepyraclostrobin preparations under simulated precipitation weather, to compare the effects of the two preparations under precipitation conditions, and to provide a theoretical basis for further practical application in the field.

[0078] Test materials: Test agents, control objects, and test locations are the same as above Test method: Fill plastic pots (7 × 7 × 10 cm) with a soil mixture (a 1:2 ratio of substrate nutrient soil to field soil). Select plump weed seeds and sow 20 seeds per pot of Alopecurus striata, Bromus gracilis, Lolium multiflorum, Artemisia selengensis, and Chenopodium album. Cover with a layer of fine soil and water to maintain a moisture layer. After sowing, cultivate in a lighted greenhouse. The greenhouse temperature is approximately 25°C during the day and 15°C at night, under natural light conditions. 24 hours after sowing, seal the soil of the weed pots with a soil spray according to the above-sprayed dosage. An equal amount of water is used as a control. Each treatment consists of 30 pots, replicated four times. Spraying was performed using a bioassay spray tower (model: NJ22-3WPSH-500D) purchased from Beijing Haifuda Technology Co., Ltd., with a rotation speed of 6 rpm, a spray height of 25 cm, an effective spray width of 30 cm, and a flow rate of 210 mL / min. The spray volume for each treatment (30 pots) was 40 mL (Note: Normal field soil spray application rate is 30-45 L of water / mu). Cultivation was continued after application.

[0079] Precipitation conditions: On the second day after application, simulate precipitation by spraying all potted plants with a fine mist spray for 0.5 h at a nozzle flow rate of 300 mL / min. After spraying, continue cultivation and observation in the greenhouse. Continue management under normal conditions and temperature conditions as above.

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

[0081] Statistics: Statistics of weed emergence rate 7 days after application: Germination rate = number of germinations / number of seeds × 100% The statistics of weed emergence rate of each test case are shown in Table 10.

[0082] Table 10 ; The test results in Table 10 show that under simulated precipitation conditions, the emergence rate of 85% sulfonepyraclostrobin WDG2 (Crystal Form A) for the five weed species was 10-15% higher than that of 85% sulfonepyraclostrobin WDG1 (Crystal Form S). 85% sulfonepyraclostrobin WDG1 (Crystal Form S) demonstrated better weed control and a lower emergence rate. 85% sulfonepyraclostrobin WDG1 (Crystal Form S) maintained better efficacy under rainfall conditions and exhibited superior resistance to rainwater washout.

[0083] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A crystalline form S of a dihydroisoxazole compound represented by formula I, characterized in that: The X-ray powder diffraction pattern of the crystal form S measured at 25°C using Cu-Kα radiation has only one characteristic diffraction peak at a diffraction angle 2θ between 17.5° and 18.5°. 。 2. The crystal form S according to claim 1, characterized in that The crystalline form S has diffraction peaks at least at the following diffraction angles 2θ in the X-ray powder diffraction pattern measured at 25°C using Cu-Kα rays: 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°.

3. The crystal form S according to claim 2, characterized in that The X-ray powder diffraction pattern of the crystalline form S measured at 25°C using Cu-Kα rays also includes diffraction peaks at the following diffraction angles 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°.

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

5. A method for preparing the crystalline form S of the dihydroisoxazole compound represented by formula I according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: 1) adding the dihydroisoxazole compound represented by formula I to N,N-dimethylacetamide and heating until completely dissolved to obtain a hot liquid; 2) Pour the hot liquid from step 1) into a poor solvent to precipitate crystals; 3) Filtering, drying, and maintaining constant weight to obtain the crystalline form S of the dihydroisoxazole compound represented by Formula I.

6. The preparation method according to claim 5, 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 expressed in g and the volume is expressed in mL.

7. The preparation method according to claim 5 or 6, characterized in that: In step 2), the poor solvent is selected from at least one of water, methanol, ethanol and isopropanol.

8. A crystalline 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 5 to 7.

9. A pesticide composition, characterized in that The invention comprises the crystal form S of the dihydroisoxazole compound represented by formula I according to any one of claims 1 to 4 and 8, and at least one excipient acceptable for pesticides.

10. Use of the crystalline form S of the dihydroisoxazole compound represented by formula I according to any one of claims 1 to 4 and 8 or the pesticide composition according to claim 9, characterized in that: The application is application in preparing herbicide formulations.

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