Pleuromutilin and kasugamycin composition and preparation method thereof

Abstract

The invention relates to the technical field of pesticide compositions, in particular to a pleuromutilin and kasugamycin composition and a preparation method thereof.According to the pleuromutilin and kasugamycin composition and the preparation method thereof, by conducting isopropanolamine, MOF material and biochar modification on pleuromutilin and optimizing the proportion of all the components and the preparation process, compared with the prior art, the pleuromutilin and kasugamycin composition has remarkable advantages. Firstly, the solubility, the stability and the action mode with pathogenic bacteria of the modified pleuromutilin are optimized, and the comprehensive performance of the pleuromutilin is enhanced through introduction of isopropanolamine, an MOF material and biochar; and secondly, the modified pleuromutilin is compounded with kasugamycin, so that the antibacterial spectrum is greatly widened, the limitation of a single medicament or a simple compound medicament is overcome, and the modified pleuromutilin has an efficient prevention and treatment effect on plant bacterial diseases such as citrus canker and rice bacterial streak, and has a wide application prospect in agricultural production.

Description

Technical Field

[0001] The invention relates to the technical field of pesticide compositions, and in particular to a composition of pleuromutilin and kasugamycin and a preparation method thereof. Background Art

[0002] Citrus canker and rice bacterial leaf streak are diseases that cause serious harm to citrus and rice, two important crops in agricultural production.

[0003] Citrus is one of the most widely grown fruit crops in the world. Citrus canker is a bacterial disease caused by Xanthomonas citri subsp. citri. The disease mainly harms the leaves, branches and fruits of citrus, causing ulcer-like lesions on the leaves and reducing the quality of the fruit, which seriously affects the appearance and commercial value of citrus, resulting in a significant reduction in citrus production and huge economic losses to the citrus industry. In citrus-growing areas, especially in warm and humid climates, citrus canker is prone to large-scale outbreaks, making prevention and control difficult.

[0004] Rice is one of the most important food crops in the world. Bacterial leaf streak of rice is a bacterial disease caused by Xanthomonas oryzae pv. oryzicola. This disease mainly infects rice leaves. The lesions are initially small dark green water-soaked spots, which then quickly expand into thin yellow-brown stripes. In severe cases, the leaves will turn yellow, affecting the photosynthesis of rice, resulting in stunted plant growth, reduced number of grains per panicle, and reduced thousand-grain weight, ultimately causing a significant drop in rice yield. In some rice-producing areas, the frequent occurrence of bacterial leaf streak of rice poses a potential threat to food security.

[0005] In the process of dealing with these diseases, there is room for improvement in traditional pesticide ingredients in terms of improving efficacy, reducing drug release rate, and enhancing stability. Pleuromutilin itself has antibacterial activity and can inhibit the growth and reproduction of pathogens to a certain extent. Kasugamycin, as an agricultural antibiotic, has a preventive and therapeutic effect on plant bacterial diseases. It can interfere with the synthesis process of pathogenic bacteria proteins, thereby achieving the purpose of inhibiting the growth of pathogens. However, when using kasugamycin alone, there is a problem that the antibacterial spectrum is not comprehensive enough. For example, when facing some highly resistant pathogens, its preventive and therapeutic effect will be greatly reduced, and simply mixing pleuromutilin and kasugamycin for disease prevention and control still has great limitations.

[0006] Therefore, according to the above-mentioned related technologies, it is urgent to develop a composition of pleuromutilin and kasugamycin and a preparation method thereof. Summary of the invention

[0007] In view of this, the object of the present invention is to provide a composition of pleuromutilin and kasugamycin and a preparation method thereof, so as to solve the problem of limitations of single agents or simple compound agents in the prior art.

[0008] Based on the above purpose, the present invention provides a composition of pleuromutilin and kasugamycin and a preparation method thereof.

[0009] A composition of pleuromutilin and kasugamycin, comprising the following raw materials in parts by weight: 22-26 parts of active ingredients, 6-9 parts of surfactants, 1.2-1.7 parts of thickeners, 3-5 parts of antifreeze agents, 0.3-0.5 parts of defoaming agents, and 75-80 parts of deionized water; The active ingredient is obtained by mixing pleuromutilin, modified pleuromutilin and kasugamycin; The modified pleuromutilin is obtained by mixing modified pleuromutilin A, modified pleuromutilin B and modified pleuromutilin C; The modified pleuromutilin A is pleuromutilin modified with isopropanolamine; The modified pleuromutilin B is pleuromutilin modified by MOF material; The modified pleuromutilin C is pleuromutilin modified with biochar.

[0010] Preferably, the mass ratio of pleuromutilin, modified pleuromutilin and kasugamycin in the active ingredient is 18-20:1.5-1.8:2.5-4.2.

[0011] Preferably, the mass ratio of modified pleuromutilin A, modified pleuromutilin B and modified pleuromutilin C in the modified pleuromutilin is 0.8-0.9:0.2-0.3:0.5-0.6.

[0012] Preferably, the preparation process of the modified pleuromutilin A is as follows: Step A1. Activation of pleuromutilin: adding a halogenating agent to a pleuromutilin solution at 2-3°C and pH=8-10 to obtain activated pleuromutilin; Step A2. Pretreatment of isopropanolamine: reacting isopropanolamine, a protective agent and triethylamine at 4-6° C. for 3-4 h to obtain a mixture A; Step A3. reacting mixture A, halogenated hydrocarbon and catalyst at 78-83° C. for 6-10 h to obtain pretreated isopropanolamine; Step A4. The activated pleuromutilin and the pretreated isopropanolamine are mixed at 4-6°C, a catalyst is added, and the mixture is stirred at 46-50°C for 6-8h. After the reaction is completed, the reaction solution is extracted and recrystallized to obtain modified pleuromutilin A.

[0013] Preferably, the halogenating agent in step A1 is any one of phosphorus tribromide and thionyl chloride; The molar ratio of pleuromutilin to the halogenating agent in the pleuromutilin solution and the halogenating agent in step A1 is 1-1.2:1.3-1.5; The protective agent in step A2 is any one of di-tert-butyl dicarbonate and benzyl chloroformate; The molar ratio of isopropanolamine, protective agent and triethylamine in step A2 is 1.3-1.8:1-1.2:2-2.2; In step A3, the halogenated hydrocarbon is methyl iodide, and the catalyst is phosphoric acid with a concentration of 1.2-1.5 mol / L; The molar ratio of the mixture A to the halogenated hydrocarbon in step A3 is 1-1.2:1.2-1.5; The mass ratio of the mixture A to the catalyst in step A3 is 90-100:12-15; The molar ratio of the activated pleuromutilin to the treated isopropanolamine and the catalyst in step A4 is 1-1.2:1.3-1.5:2-2.4; The catalyst in step A4 is any one of triethylamine and pyridine.

[0014] Preferably, the preparation process of the modified pleuromutilin B is as follows: Step B1. Mix the methanol solution of the ligand and the methanol solution of zinc nitrate, stir at a stirring speed of 700-800 rpm for 16-20 hours, stand at room temperature for 16-20 hours after the reaction is completed, centrifuge at a speed of 7000-9000 rpm for 3-5 minutes, wash with methanol, dry at 40-60°C for 8-10 hours, and finally treat in a hydrogen atmosphere at 300-400°C for 2-4 hours to obtain a MOF material; Step B2. reacting pleuromutilin and a modifying agent at 40-50° C. for 3-5 h to obtain activated pleuromutilin; Step B3. Stir the MOF material and activated pleuromutilin at 60-70° C. for 20-24 hours. After the reaction is completed, separate and purify to obtain modified pleuromutilin B.

[0015] Preferably, in step B1, the ligand is 1,2,4-triazole, and the concentration of the methanol solution of the ligand is 0.3-0.5 mol / L; the concentration of the methanol solution of zinc nitrate is 0.2-0.4 mol / L; The molar ratio of the ligand to zinc nitrate in step B1 is 1-1.5:4-6; The molar ratio of pleuromutilin to the modifying agent in step B2 is 1-1.8:3-6; The modifying agent in step B2 is any one of sodium dodecyl sulfate, polyethylene glycol, 3-aminopropyltriethoxysilane, glutaraldehyde, citric acid and ethylenediaminetetraacetic acid; The mass ratio of the MOF material to the activated pleuromutilin in step B3 is 1.2-1.5:0.7-0.9.

[0016] Preferably, the preparation process of the modified pleuromutilin C is as follows: Step C1. drying the biochar at 80-100° C. for 4-6 hours, grinding the dried biochar, and finally passing through a 100-120 mesh sieve to obtain pretreated biochar; Step C2. Add a solvent to a reaction vessel, then dissolve pleuromutilin in the solvent, stir evenly to form a pleuromutilin solution, then add the pretreated biochar, stir and mix, and react at 60-80° C. for 10-12 hours; Step C3. After the reaction is completed, the reaction mixture is filtered, the solid product is washed, and finally dried at 60-80° C. for 4-6 hours to obtain modified pleuromutilin C.

[0017] Preferably, the biochar in step C1 is lignocellulose; The solvent in step C2 is any one of methanol, ethanol and dichloromethane; The usage ratio of pleuromutilin, solvent and pretreated biochar in step C2 is 1-2 g: 200-300 mL: 8-12 g.

[0018] A method for preparing a composition of pleuromutilin and kasugamycin comprises the following steps: The surfactant and the antifreeze agent are dissolved in deionized water, the active ingredient and the thickener are added, the mixture is evenly mixed and then pumped into a sand grinder for grinding, and a defoamer is added. When D90 is less than 8 μm, stirring is stopped, and the mixture is filtered to obtain a composition of pleuromutilin and kasugamycin; The surfactant is any one of sodium diphenylmethanesulfonate, sodium naphthalenesulfonate formaldehyde condensate and sodium p-toluenesulfonate; The antifreeze agent is sodium chloride; The thickener is magnesium aluminum silicate SF-40; The defoaming agent is polydimethylsiloxane.

[0019] Beneficial effects of the present invention: The composition of pleuromutilin and kasugamycin provided by the present invention and the preparation method thereof, by modifying pleuromutilin with isopropanolamine, MOF material and biochar, and optimizing the proportion of each component and the preparation process, has significant advantages compared with the prior art. First, the modified pleuromutilin is optimized in solubility, stability and the mode of action with pathogens, and the introduction of isopropanolamine, MOF material and biochar enhances its comprehensive performance; secondly, these modified pleuromutilins are compounded with kasugamycin, which greatly broadens the antibacterial spectrum, overcomes the limitations of a single agent or a simple compound agent, and shows an efficient prevention and control effect on plant bacterial diseases such as citrus canker and rice bacterial streak, has broad application prospects in agricultural production, can effectively reduce the yield loss of crops caused by diseases, ensure the stability and sustainable development of agricultural production, and improve the quality and economic benefits of agricultural products. DETAILED DESCRIPTION

[0020] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0021] Example 1: A method for preparing a composition of pleuromutilin and kasugamycin, comprising the following steps: S1. Activation of pleuromutilin: adding phosphorus tribromide to a pleuromutilin solution at 2°C and pH 8 to obtain activated pleuromutilin, wherein the molar ratio of pleuromutilin to phosphorus tribromide in the pleuromutilin solution and phosphorus tribromide is 1:1.3; S2. Pretreatment of isopropanolamine: 13 mol of isopropanolamine, 10 mol of di-tert-butyl dicarbonate and 20 mol of triethylamine were reacted at 4 ° C for 3 h to obtain a mixture A; S3. The mixture A, methyl iodide and phosphoric acid at a concentration of 1.2 mol / L were reacted at 78 ° C for 6 h to obtain pretreated isopropanolamine, wherein the molar ratio of the mixture A to methyl iodide was 1:1.2, and the mass ratio of the mixture A to the catalyst was 90:12; S4. 1 mol of activated pleuromutilin and 1.3 mol of pretreated isopropanolamine were mixed at 4°C, 2 mol of triethylamine was added, and the mixture was stirred at 46°C for 6 h. After the reaction was completed, the reaction solution was extracted and recrystallized to obtain modified pleuromutilin A; S5. A methanol solution of 1,2,4-triazole with a concentration of 0.3 mol / L and a methanol solution of zinc nitrate with a concentration of 0.2 mol / L were mixed, stirred at a stirring speed of 700 rpm for 16 hours, and after the reaction was completed, allowed to stand at room temperature for 16 hours, and then centrifuged at a speed of 7000 rpm for 3 minutes. After washing with methanol, it was dried at 40°C for 8 hours, and finally treated in a hydrogen atmosphere at 300°C for 2 hours to obtain a MOF material, wherein the molar ratio of 1,2,4-triazole to zinc nitrate was 10:40; S6. reacting 10 mol of pleuromutilin and 30 mol of sodium dodecyl sulfate at 40° C. for 3 h to obtain activated pleuromutilin; S7. 12g MOF material and 7g activated pleuromutilin were stirred at 60 ° C for 20h. After the reaction was completed, the modified pleuromutilin B was obtained by separation and purification; S8. drying the biochar at 80° C. for 4 h, grinding the dried biochar, and finally passing through a 100-mesh sieve to obtain pretreated biochar; S9. Add 200 mL of methanol to the reaction container, then dissolve 1 g of pleuromutilin in the solvent, stir evenly to form a pleuromutilin solution, then add 8 g of pretreated biochar, stir and mix, and react at 60° C. for 10 h; S10. After the reaction is completed, the reaction mixture is filtered, the solid product is washed, and finally dried at 60° C. for 4 h to obtain modified pleuromutilin C; S11. 8 g of modified pleuromutilin A, 2 g of modified pleuromutilin B and 5 g of modified pleuromutilin C were mixed to obtain modified pleuromutilin; S12. 18 g of pleuromutilin, 1.5 g of modified pleuromutilin and 2.5 g of kasugamycin were mixed to obtain an active ingredient; S13. Dissolve 6 g of sodium diphenylmethanesulfonate and 3 g of sodium chloride in 75 g of deionized water, add 22 g of active ingredient and 1.2 g of magnesium aluminum silicate SF-40, mix well and pump into a sand grinder for grinding, then add 0.3 g of polydimethylsiloxane, and stop stirring when D90 is less than 8 μm, and filter to obtain a composition of pleuromutilin and kasugamycin.

[0022] Example 2: A method for preparing a composition of pleuromutilin and kasugamycin, comprising the following steps: S1. Activation of pleuromutilin: adding thionyl chloride to a pleuromutilin solution at 2.5°C and pH = 9 to obtain activated pleuromutilin, wherein the molar ratio of pleuromutilin to thionyl chloride in the pleuromutilin solution and thionyl chloride is 1.05:1.35; S2. Pretreatment of isopropanolamine: 14 mol of isopropanolamine, 10.5 mol of benzyl chloroformate and 20.5 mol of triethylamine were reacted at 5° C. for 3.5 h to obtain a mixture A; S3. The mixture A, methyl iodide and phosphoric acid at a concentration of 1.3 mol / L were reacted at 79 ° C for 7h to obtain pretreated isopropanolamine, wherein the molar ratio of the mixture A and methyl iodide was 1.1:1.3, and the mass ratio of the mixture A and the catalyst was 92:13; S4. 1.05 mol of activated pleuromutilin and 1.35 mol of pretreated isopropanolamine were mixed at 5 ° C, 2.1 mol of pyridine was added, and the mixture was stirred at 47 ° C for 7 h. After the reaction was completed, the reaction solution was extracted and recrystallized to obtain modified pleuromutilin A; S5. A methanol solution of 1,2,4-triazole with a concentration of 0.4 mol / L and a methanol solution of zinc nitrate with a concentration of 0.25 mol / L were mixed, stirred at a stirring speed of 740 rpm for 17 hours, and after the reaction was completed, allowed to stand at room temperature for 17 hours, and then centrifuged at a speed of 7400 rpm for 4 minutes. After washing with methanol, it was dried at 44°C for 9 hours, and finally treated in a hydrogen atmosphere at 320°C for 3 hours to obtain a MOF material, wherein the molar ratio of 1,2,4-triazole to zinc nitrate was 11:44; S6. reacting 12 mol of pleuromutilin and 36 mol of polyethylene glycol at 42° C. for 4 h to obtain activated pleuromutilin; S7. 13g MOF material and 7.5g activated pleuromutilin were stirred at 62 ° C for 21h. After the reaction was completed, the modified pleuromutilin B was obtained by separation and purification; S8. drying the biochar at 84° C. for 5 h, grinding the dried biochar, and finally passing through a 105-mesh sieve to obtain pretreated biochar; S9. Add 220 mL of ethanol to the reaction container, then dissolve 1.2 g of pleuromutilin in the solvent, stir evenly to form a pleuromutilin solution, then add 9 g of pretreated biochar, stir and mix, and react at 64° C. for 11 h; S10. After the reaction is completed, the reaction mixture is filtered, the solid product is washed, and finally dried at 64° C. for 5 h to obtain modified pleuromutilin C; S11. 8.2 g of modified pleuromutilin A, 2.2 g of modified pleuromutilin B and 5.2 g of modified pleuromutilin C were mixed to obtain modified pleuromutilin; S12. 18.4 g of pleuromutilin, 1.6 g of modified pleuromutilin and 2.8 g of kasugamycin were mixed to obtain an active ingredient; S13. Dissolve 7 g of sodium naphthalenesulfonate formaldehyde condensate and 4 g of sodium chloride in 76 g of deionized water, add 23 g of active ingredient and 1.3 g of magnesium aluminum silicate SF-40, mix well and pump into a sand grinder for grinding, then add 0.4 g of polydimethylsiloxane, and stop stirring when D90 is less than 8 μm, and filter to obtain a composition of pleuromutilin and kasugamycin.

[0023] Example 3: A method for preparing a composition of pleuromutilin and kasugamycin, comprising the following steps: S1. Activation of pleuromutilin: adding phosphorus tribromide to a pleuromutilin solution at 3°C ​​and pH = 10 to obtain activated pleuromutilin, wherein the molar ratio of pleuromutilin to phosphorus tribromide in the pleuromutilin solution and phosphorus tribromide is 1.1:1.4; S2. Pretreatment of isopropanolamine: 15 mol of isopropanolamine, 10.8 mol of di-tert-butyl dicarbonate and 20.8 mol of triethylamine were reacted at 6 ° C for 3-3.5-4-3-3.5-4h to obtain a mixture A; S3. The mixture A, methyl iodide and phosphoric acid at a concentration of 1.4 mol / L were reacted at 80 ° C for 8h to obtain pretreated isopropanolamine, wherein the molar ratio of the mixture A and methyl iodide was 1.2: 1.4, and the mass ratio of the mixture A and the catalyst was 94: 14; S4. 1.1 mol of activated pleuromutilin and 1.4 mol of pretreated isopropanolamine were mixed at 6 ° C, 2.2 mol of triethylamine was added, and the mixture was stirred at 48 ° C for 8 h. After the reaction was completed, the reaction solution was extracted and recrystallized to obtain modified pleuromutilin A; S5. A methanol solution of 1,2,4-triazole with a concentration of 0.5 mol / L and a methanol solution of zinc nitrate with a concentration of 0.28 mol / L were mixed, stirred at a stirring speed of 780 rpm for 18 hours, and after the reaction was completed, allowed to stand at room temperature for 18 hours, and then centrifuged at a speed of 7800 rpm for 5 minutes. After washing with methanol, it was dried at 48°C for 10 hours, and finally treated in a hydrogen atmosphere at 340°C for 4 hours to obtain a MOF material, wherein the molar ratio of 1,2,4-triazole to zinc nitrate was 12:48; S6. 13 mol of pleuromutilin and 30-36-42-48-54-60 mol of 3-aminopropyltriethoxysilane were reacted at 44° C. for 5 h to obtain activated pleuromutilin; S7. 14gMOF material and 8g activated pleuromutilin were stirred at 64°C for 22h. After the reaction was completed, the modified pleuromutilin B was obtained by separation and purification; S8. drying the biochar at 88° C. for 6 h, grinding the dried biochar, and finally passing the biochar through a 110-mesh sieve to obtain pretreated biochar; S9. Add 240 mL of dichloromethane to the reaction vessel, then dissolve 1.4 g of pleuromutilin in the solvent, stir evenly to form a pleuromutilin solution, then add 10 g of pretreated biochar, stir and mix, and react at 68° C. for 12 h; S10. After the reaction is completed, the reaction mixture is filtered, the solid product is washed, and finally dried at 68° C. for 6 h to obtain modified pleuromutilin C; S11. 8.4 g of modified pleuromutilin A, 2.4 g of modified pleuromutilin B and 5.4 g of modified pleuromutilin C were mixed to obtain modified pleuromutilin; S12. 18.8 g of pleuromutilin, 1.7 g of modified pleuromutilin and 3.2 g of kasugamycin were mixed to obtain an active ingredient; S13. Dissolve 8 g of sodium p-toluenesulfonate and 5 g of sodium chloride in 77 g of deionized water, add 24 g of the active ingredient and 1.4 g of magnesium aluminum silicate SF-40, mix well and pump into a sand grinder for grinding, then add 0.5 g of polydimethylsiloxane, and stop stirring when D90 is less than 8 μm, and filter to obtain a composition of pleuromutilin and kasugamycin.

[0024] Example 4: A method for preparing a composition of pleuromutilin and kasugamycin, comprising the following steps: S1. Activation of pleuromutilin: adding thionyl chloride to a pleuromutilin solution at 2°C and pH = 8 to obtain activated pleuromutilin, wherein the molar ratio of pleuromutilin to thionyl chloride in the pleuromutilin solution and thionyl chloride is 1.15:1.42; S2. Pretreatment of isopropanolamine: 16 mol of isopropanolamine, 11.2 mol of benzyl chloroformate and 21 mol of triethylamine were reacted at 4° C. for 3 h to obtain a mixture A; S3. The mixture A, methyl iodide and phosphoric acid at a concentration of 1.3 mol / L were reacted at 81° C. for 9 h to obtain pretreated isopropanolamine, wherein the molar ratio of the mixture A to methyl iodide was 1:1.3, and the mass ratio of the mixture A to the catalyst was 96:13; S4. 1.15 mol of activated pleuromutilin and 1.45 mol of pretreated isopropanolamine were mixed at 4 ° C, 2.3 mol of pyridine was added, and the mixture was stirred at 49 ° C for 6 h. After the reaction was completed, the reaction solution was extracted and recrystallized to obtain modified pleuromutilin A; S5. A methanol solution of 1,2,4-triazole with a concentration of 0.3 mol / L and a methanol solution of zinc nitrate with a concentration of 0.3 mol / L were mixed, stirred at a stirring speed of 820 rpm for 19 hours, and after the reaction was completed, allowed to stand at room temperature for 19 hours, and then centrifuged at a speed of 8200 rpm for 3 minutes. After washing with methanol, it was dried at 52°C for 9 hours, and finally treated in a hydrogen atmosphere at 360°C for 2 hours to obtain a MOF material, wherein the molar ratio of 1,2,4-triazole to zinc nitrate was 13:52; S6. reacting 16 mol of pleuromutilin and 48 mol of glutaraldehyde at 46° C. for 3 h to obtain activated pleuromutilin; S7. 13g MOF material and 8g activated pleuromutilin were stirred at 66 ° C for 23h. After the reaction was completed, the modified pleuromutilin B was obtained by separation and purification; S8. drying the biochar at 92° C. for 4 h, grinding the dried biochar, and finally passing the biochar through a 115-mesh sieve to obtain pretreated biochar; S9. Add 260 mL of methanol to the reaction container, then dissolve 1.6 g of pleuromutilin in the solvent, stir evenly to form a pleuromutilin solution, then add 11 g of pretreated biochar, stir and mix, and react at 72° C. for 11 h; S10. After the reaction is completed, the reaction mixture is filtered, the solid product is washed, and finally dried at 72° C. for 4 h to obtain modified pleuromutilin C; S11. 8.6 g of modified pleuromutilin A, 2.6 g of modified pleuromutilin B and 5.6 g of modified pleuromutilin C were mixed to obtain modified pleuromutilin; S12. 19.2 g of pleuromutilin, 1.8 g of modified pleuromutilin and 3.6 g of kasugamycin were mixed to obtain an active ingredient; S13. Dissolve 9 g of sodium diphenylmethanesulfonate and 5 g of sodium chloride in 78 g of deionized water, add 25 g of the active ingredient and 1.5 g of magnesium aluminum silicate SF-40, mix well and pump into a sand grinder for grinding, then add 0.5 g of polydimethylsiloxane, and stop stirring when D90 is less than 8 μm, and filter to obtain a composition of pleuromutilin and kasugamycin.

[0025] Example 5: A method for preparing a composition of pleuromutilin and kasugamycin, comprising the following steps: S1. Activation of pleuromutilin: adding phosphorus tribromide to a pleuromutilin solution at 2.5°C and pH = 9 to obtain activated pleuromutilin, wherein the molar ratio of pleuromutilin to phosphorus tribromide in the pleuromutilin solution and phosphorus tribromide is 1.18:1.45; S2. Pretreatment of isopropanolamine: 17 mol of isopropanolamine, 11.5 mol of di-tert-butyl dicarbonate and 21.5 mol of triethylamine were reacted at 5 ° C for 3-3.5-4-3-3.5-4h to obtain a mixture A; S3. The mixture A, methyl iodide and phosphoric acid at a concentration of 1.4 mol / L were reacted at 82 ° C for 8 h to obtain pretreated isopropanolamine, wherein the molar ratio of the mixture A to methyl iodide was 1.1:1.4, and the mass ratio of the mixture A to the catalyst was 98:14; S4. 1.18 mol of activated pleuromutilin and 1.49 mol of pretreated isopropanolamine were mixed at 5 ° C, 2.2 mol of triethylamine was added, and the mixture was stirred at 47 ° C for 7 h. After the reaction was completed, the reaction solution was extracted and recrystallized to obtain modified pleuromutilin A; S5. A methanol solution of 1,2,4-triazole with a concentration of 0.4 mol / L and a methanol solution of zinc nitrate with a concentration of 0.35 mol / L were mixed, stirred at a stirring speed of 860 rpm for 18 hours, and after the reaction was completed, allowed to stand at room temperature for 18 hours, and then centrifuged at a speed of 8600 rpm for 4 minutes. After washing with methanol, it was dried at 56°C for 8 hours, and finally treated in a hydrogen atmosphere at 380°C for 3 hours to obtain a MOF material, wherein the molar ratio of 1,2,4-triazole to zinc nitrate was 14:56; S6. 17 mol of pleuromutilin and 54 mol of citric acid were reacted at 48° C. for 4 h to obtain activated pleuromutilin; S7. 14gMOF material and 8.5g activated pleuromutilin were stirred at 68 ° C for 22h. After the reaction was completed, the modified pleuromutilin B was obtained by separation and purification; S8. drying the biochar at 96° C. for 5 h, grinding the dried biochar, and finally passing the biochar through a 120-mesh sieve to obtain pretreated biochar; S9. Add 280 mL of ethanol to the reaction container, then dissolve 1.8 g of pleuromutilin in the solvent, stir evenly to form a pleuromutilin solution, then add 10 g of pretreated biochar, stir and mix, and react at 76° C. for 10 h; S10. After the reaction is completed, the reaction mixture is filtered, the solid product is washed, and finally dried at 76° C. for 5 h to obtain modified pleuromutilin C; S11. 8.8 g of modified pleuromutilin A, 2.8 g of modified pleuromutilin B and 5.8 g of modified pleuromutilin C were mixed to obtain modified pleuromutilin; S12. 19.6 g of pleuromutilin, 1.7 g of modified pleuromutilin and 4.0 g of kasugamycin were mixed to obtain an active ingredient; S13. Dissolve 7 g of sodium naphthalenesulfonate formaldehyde condensate and 4 g of sodium chloride in 79 g of deionized water, add 26 g of active ingredient and 1.6 g of magnesium aluminum silicate SF-40, mix well and pump into a sand grinder for grinding, then add 0.4 g of polydimethylsiloxane, and stop stirring after D90 is less than 8 μm, and filter to obtain a composition of pleuromutilin and kasugamycin.

[0026] Example 6: A method for preparing a composition of pleuromutilin and kasugamycin, comprising the following steps: S1. Activation of pleuromutilin: adding thionyl chloride to a pleuromutilin solution at 3°C ​​and pH = 10 to obtain activated pleuromutilin, wherein the molar ratio of pleuromutilin to thionyl chloride in the pleuromutilin solution and thionyl chloride is 1.2:1.5; S2. Pretreatment of isopropanolamine: 18 mol of isopropanolamine, 12 mol of benzyl chloroformate and 22 mol of triethylamine were reacted at 6° C. for 4 h to obtain a mixture A; S3. The mixture A, methyl iodide and phosphoric acid at a concentration of 1.5 mol / L were reacted at 83 ° C for 10 h to obtain pretreated isopropanolamine, wherein the molar ratio of the mixture A to methyl iodide was 1.2:1.5, and the mass ratio of the mixture A to the catalyst was 100:15; S4. 1.2 mol of activated pleuromutilin and 1.5 mol of pretreated isopropanolamine were mixed at 6°C, 2.4 mol of pyridine was added, and the mixture was stirred at 50°C for 8 h. After the reaction was completed, the reaction solution was extracted and recrystallized to obtain modified pleuromutilin A; S5. A methanol solution of 1,2,4-triazole with a concentration of 0.5 mol / L and a methanol solution of zinc nitrate with a concentration of 0.4 mol / L were mixed, stirred at a stirring speed of 800 rpm for 20 hours, and after the reaction was completed, allowed to stand at room temperature for 20 hours, and then centrifuged at a speed of 9000 rpm for 5 minutes. After washing with methanol, it was dried at 60°C for 10 hours, and finally treated in a hydrogen atmosphere at 400°C for 4 hours to obtain a MOF material, wherein the molar ratio of 1,2,4-triazole to zinc nitrate was 15:60; S6. 18 mol of pleuromutilin and 60 mol of ethylenediaminetetraacetic acid were reacted at 50° C. for 5 h to obtain activated pleuromutilin; S7. 15gMOF material and 9g activated pleuromutilin were stirred at 70 ° C for 24h. After the reaction was completed, the modified pleuromutilin B was obtained by separation and purification; S8. drying the biochar at 100° C. for 6 h, grinding the dried biochar, and finally passing the biochar through a 120-mesh sieve to obtain pretreated biochar; S9. Add 300 mL of dichloromethane to the reaction vessel, then dissolve 2 g of pleuromutilin in the solvent, stir evenly to form a pleuromutilin solution, then add 12 g of pretreated biochar, stir and mix, and react at 80° C. for 12 h; S10. After the reaction is completed, the reaction mixture is filtered, the solid product is washed, and finally dried at 80° C. for 6 h to obtain modified pleuromutilin C; S11. 9 g of modified pleuromutilin A, 3 g of modified pleuromutilin B and 6 g of modified pleuromutilin C were mixed to obtain modified pleuromutilin; S12. 20 g of pleuromutilin, 1.8 g of modified pleuromutilin and 4.2 g of kasugamycin were mixed to obtain an active ingredient; S13. Dissolve 8 g of sodium p-toluenesulfonate and 3 g of sodium chloride in 80 g of deionized water, add 24 g of active ingredient and 1.7 g of magnesium aluminum silicate SF-40, mix well and pump into a sand grinder for grinding, then add 0.3 g of polydimethylsiloxane, and stop stirring when D90 is less than 8 μm, and filter to obtain a composition of pleuromutilin and kasugamycin.

[0027] Comparative Example 1: Compared with Example 1, modified pleuromutilin was not added during the preparation of the composition of pleuromutilin and kasugamycin in this comparative example, and the remaining steps and parameters were the same and will not be repeated in this comparative example. Finally, a composition of pleuromutilin and kasugamycin was obtained.

[0028] Comparative Example 2: Compared with Example 1, this comparative example only replaces "modified pleuromutilin" with "modified pleuromutilin A", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally a composition of pleuromutilin and kasugamycin is obtained.

[0029] Comparative Example 3: Compared with Example 1, this comparative example only replaces the "modified pleuromutilin C" with "a mixture of equal amounts and the same type of biochar and pleuromutilin", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally a composition of pleuromutilin and kasugamycin is obtained.

[0030] Comparative Example 4: Compared with Example 1, this comparative example only adjusts the dosage of "modified pleuromutilin A" from "8g" to "4g", and the remaining steps and parameters are the same, which will not be repeated in this comparative example. Finally, a composition of pleuromutilin and kasugamycin is obtained.

[0031] Comparative Example 5: Compared with Example 1, only the amount of "isopropanolamine" in this comparative example is adjusted from "1.3 mol" to "0.8 mol", and the remaining steps and parameters are the same, which will not be repeated in this comparative example. Finally, a composition of pleuromutilin and kasugamycin is obtained.

[0032] Comparative Example 6: Compared with Example 1, this comparative example only adjusts the amount of "MOF material" from "12g" to "8g", and the remaining steps and parameters are the same, which will not be repeated in this comparative example. Finally, a composition of pleuromutilin and kasugamycin is obtained.

[0033] Comparative Example 7: Compared with Example 1, this comparative example only adjusts the amount of "biochar" from "8g" to "5g", and the remaining steps and parameters are the same, which will not be repeated in this comparative example. Finally, a composition of pleuromutilin and kasugamycin is obtained.

[0034] Performance test: The following performance test was performed on the composition of pleuromutilin and kasugamycin prepared in Examples 1 to 6 and Comparative Examples 1 to 7: Antibacterial activity test: The composition prepared in each embodiment and comparative example was prepared into a solution of a certain concentration by using a paper diffusion method, and an appropriate amount of the solution was dripped onto a sterile filter paper. After drying, the solution was placed on a culture medium plate inoculated with Xanthomonas citri subsp. citri or Xanthomonas oryzaepv. oryzicola, and cultured at a suitable temperature (such as 28°C) for a certain period of time (such as 48h). The diameter of the inhibition zone (in mm) was measured and recorded. The larger the diameter of the inhibition zone, the better the inhibitory effect of the composition on pathogens. It is generally believed that an inhibition zone diameter of ≥15 mm has a strong antibacterial activity, so as to evaluate the inhibitory ability of the composition on pathogens; Drug release performance test: using the dialysis bag method, a certain amount of the composition is placed in a dialysis bag, placed in a buffer solution simulating the in vivo environment of the plant (such as PBS buffer, pH 7.4), oscillated in a constant temperature water bath (such as 37°C), sampled at regular intervals, and the content of pleuromutilin and kasugamycin in the buffer solution is determined by high performance liquid chromatography (HPLC), and the drug release curve is drawn. The drug release curve should show a reasonable sustained release trend, such as a certain burst release in the initial stage, followed by a slow and continuous release to ensure that the drug can maintain an effective concentration at the site of action for a long time. The ideal sustained-release preparation should have a certain cumulative drug release rate (such as 70%-90%) within a specified time (such as 72h). At the end of the test, the 72h cumulative drug release rate (in %) is recorded to examine the release characteristics of the drug; Stability test: The composition is placed under high temperature (e.g., 50°C), high humidity (90% relative humidity) and light (4500 Lux) conditions for accelerated aging for a certain period of time (e.g., 10 days), and then the antibacterial activity of the aged composition is determined according to the above antibacterial activity test method, and compared with the initial antibacterial activity, the activity retention rate (in %) is calculated and recorded to evaluate the stability of the composition, wherein an activity retention rate ≥ 80% is considered to be good in stability, indicating that the composition can maintain good efficacy during storage and use; The results are shown in Table 1 below: Table 1 Data Analysis: It can be seen from Table 1 that the composition of pleuromutilin and kasugamycin prepared by the present invention has stronger antibacterial activity, longer drug release performance and higher stability. The possible reasons are as follows: The composition of pleuromutilin and kasugamycin provided by the present invention and the preparation method thereof, by modifying pleuromutilin with isopropanolamine, MOF material and biochar, and optimizing the proportion of each component and the preparation process, have significant advantages over the prior art. First, the modified pleuromutilin is optimized in solubility, stability and mode of action with pathogenic bacteria, and the introduction of isopropanolamine enhances its comprehensive performance; the loading of MOF material realizes the slow release of the drug, prolongs the action time and increases the drug concentration at the target point; the adsorption effect of biochar improves the stability and effectiveness of the drug, so that it can be better transported to the site of action. Secondly, compounding these modified pleuromutilins with kasugamycin greatly broadens the antibacterial spectrum, overcomes the limitations of a single agent or a simple compound agent, and shows efficient prevention and control effects on plant bacterial diseases such as citrus canker and rice bacterial leaf streak, has broad application prospects in agricultural production, can effectively reduce the yield loss of crops caused by diseases, ensure the stability and sustainable development of agricultural production, and improve the quality and economic benefits of agricultural products; In terms of antibacterial activity: Compared with Comparative Example 1, Examples 1-6 have significantly improved antibacterial activity. Comparative Example 1 does not add modified pleuromutilin, but simply mixes pleuromutilin and kasugamycin. The diameter of the inhibition zone against citrus canker and rice bacterial leaf streak is relatively small, about 16 mm and 14 mm, respectively, indicating that a single simple compound is difficult to effectively inhibit pathogens. In the examples, due to the introduction of isopropanolamine, MOF materials, and biochar-modified pleuromutilin, the diameter of the inhibition zone is significantly increased, such as Example 6, which can reach 25 mm for citrus canker and 24 mm for rice bacterial leaf streak. This is because the modification with isopropanolamine optimizes the way pleuromutilin acts on pathogens and enhances its antibacterial ability; MOF materials and biochar not only have their own structural characteristics that are conducive to antibacterial, but can also work synergistically with pleuromutilin and kasugamycin to broaden the antibacterial spectrum and have a good inhibitory effect on highly resistant pathogens, overcoming the problem of incomplete antibacterial spectrum of kasugamycin alone. The effects of each modified component were further verified by comparing Comparative Examples 2-7. Comparative Example 2 only uses modified pleuromutilin A, lacking the synergy of MOF material and biochar modification, and the antibacterial activity is not as good as the overall improvement of the embodiment; Comparative Example 3 changes the biochar modification method, and Comparative Examples 4-7 reduce the amount of isopropanolamine, MOF material, and biochar respectively, all of which lead to a decrease in antibacterial activity to varying degrees, proving that the sufficient presence of each modified component and synergistic coordination are the key to high antibacterial activity; In terms of drug release: the cumulative release rate of the drug in Examples 1-6 is between 82% and 90% in 72h, showing a good sustained release trend, which meets the requirements of an ideal sustained release preparation. This is due to the high specific surface area and adjustable pore structure of the MOF material, which can load pleuromutilin to achieve slow release, so that the drug can maintain an effective concentration at the site of action for a long time, ensuring the continuous effect of the drug, while the cumulative release rate of Comparative Example 1 is only 60%. Without the use of modification methods such as MOF materials, it is difficult for the drug release to achieve an ideal continuous and stable state, and it is impossible to provide sufficient drug dosage for long-term disease prevention and treatment.

[0035] Stability: The activity retention rates of the embodiments are all between 85% and 90%, and the stability is good. The good adsorption performance of biochar effectively prevents the rapid degradation of pleuromutilin, ensuring that the composition can still maintain high antibacterial activity under accelerated aging conditions such as high temperature, high humidity, and light. Comparative Example 1 has relatively poor stability, with an activity retention rate of 70%, indicating that without modification and protection such as biochar, the composition is prone to loss of efficacy during storage and use, which is not conducive to long-term effectiveness in practical applications.

[0036] In summary, through the scientific compounding of various modified pleuromutilins and kasugamycin, each component gives full play to its own advantages and works synergistically, so that the composition has excellent performance in antibacterial activity, drug release and stability, and provides strong support for the efficient prevention and control of citrus canker and rice bacterial leaf streak disease. Among them, pleuromutilins itself has antibacterial activity and has shown certain antibacterial potential. It can inhibit the growth and reproduction of pathogens to a certain extent. The pleuromutilins containing isopropanolamine may have unique properties in terms of drug solubility, stability or mode of action with pathogens due to the presence of isopropanolamine. Among them, the isopropanolamine in the pleuromutilins modified with isopropanolamine is slightly excessive, and the excess isopropanolamine can The MOF material modified pleuromutilin has a slightly excessive amount of MOF material, and the excess MOF material can react with free pleuromutilin and free kasugamycin. The biochar modified pleuromutilin has a slightly excessive amount of biochar, and the excess biochar can react with free pleuromutilin and free kasugamycin. Kasugamycin, as an agricultural antibiotic, has a preventive effect on plant bacterial diseases. It can interfere with the synthesis process of pathogenic bacteria proteins, thereby achieving the purpose of inhibiting the growth of pathogens. Metal organic framework (MOF) material is a new type of porous material with high specific surface area, adjustable pore structure, good thermal stability and other characteristics. Loading pleuromutilin on MOF material can utilize these characteristics of MOF material to achieve slow release of drugs, prolong the action time of drugs, and at the same time increase the concentration of drugs at the target site, thereby enhancing the antibacterial effect of drugs. Biochar is a carbon-rich solid substance obtained by pyrolysis of biomass under anaerobic or oxygen-limited conditions, and has good adsorption properties. Biochar-loaded pleuromutilin can improve the stability of pleuromutilin and prevent it from rapid degradation in the environment. Biochar can also serve as a carrier to better transport pleuromutilin to the site of action, thereby improving the effectiveness of pleuromutilin. Combining these loaded pleuromutilins with kasugamycin can overcome the limitations of existing single agents or simple compound agents.

[0037] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0038] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A composition of pleuromutilin and kasugamycin, characterized in that: The invention comprises the following raw materials in parts by weight: 22-26 parts of active ingredients, 6-9 parts of surfactants, 1.2-1.7 parts of thickeners, 3-5 parts of antifreeze agents, 0.3-0.5 parts of defoaming agents, and 75-80 parts of deionized water; The active ingredient is obtained by mixing pleuromutilin, modified pleuromutilin and kasugamycin; The modified pleuromutilin is obtained by mixing modified pleuromutilin A, modified pleuromutilin B and modified pleuromutilin C; The modified pleuromutilin A is pleuromutilin modified with isopropanolamine; The modified pleuromutilin B is pleuromutilin modified by MOF material; The modified pleuromutilin C is pleuromutilin modified with biochar.

2. The composition of pleuromutilin and kasugamycin according to claim 1, characterized in that The mass ratio of pleuromutilin, modified pleuromutilin and kasugamycin in the active ingredient is 18-20:1.5-1.8:2.5-4.

2.

3. The composition of pleuromutilin and kasugamycin according to claim 1, characterized in that The mass ratio of modified pleuromutilin A, modified pleuromutilin B and modified pleuromutilin C in the modified pleuromutilin is 0.8-0.9:0.2-0.3:0.5-0.

6.

4. The composition of pleuromutilin and kasugamycin according to claim 1, characterized in that The preparation process of the modified pleuromutilin A is as follows: Step A1. Activation of pleuromutilin: adding a halogenating agent to a pleuromutilin solution at 2-3°C and pH=8-10 to obtain activated pleuromutilin; Step A2. Pretreatment of isopropanolamine: reacting isopropanolamine, a protective agent and triethylamine at 4-6° C. for 3-4 h to obtain a mixture A; Step A3. reacting mixture A, halogenated hydrocarbon and catalyst at 78-83° C. for 6-10 h to obtain pretreated isopropanolamine; Step A4. The activated pleuromutilin and the pretreated isopropanolamine are mixed at 4-6°C, a catalyst is added, and the mixture is stirred at 46-50°C for 6-8h. After the reaction is completed, the reaction solution is extracted and recrystallized to obtain modified pleuromutilin A.

5. The composition of pleuromutilin and kasugamycin according to claim 4, characterized in that The halogenating agent in step A1 is any one of phosphorus tribromide and thionyl chloride; The molar ratio of pleuromutilin to the halogenating agent in the pleuromutilin solution and the halogenating agent in step A1 is 1-1.2:1.3-1.5; The protective agent in step A2 is any one of di-tert-butyl dicarbonate and benzyl chloroformate; The molar ratio of isopropanolamine, protective agent and triethylamine in step A2 is 1.3-1.8:1-1.2:2-2.2; In step A3, the halogenated hydrocarbon is methyl iodide, and the catalyst is phosphoric acid with a concentration of 1.2-1.5 mol / L; The molar ratio of the mixture A to the halogenated hydrocarbon in step A3 is 1-1.2:1.2-1.5; The mass ratio of the mixture A to the catalyst in step A3 is 90-100:12-15; The molar ratio of the activated pleuromutilin to the treated isopropanolamine and the catalyst in step A4 is 1-1.2:1.3-1.5:2-2.4; The catalyst in step A4 is any one of triethylamine and pyridine.

6. The composition of pleuromutilin and kasugamycin according to claim 1, characterized in that The preparation process of the modified pleuromutilin B is as follows: Step B1. Mix the methanol solution of the ligand and the methanol solution of zinc nitrate, stir at a stirring speed of 700-800 rpm for 16-20 hours, stand at room temperature for 16-20 hours after the reaction is completed, centrifuge at a speed of 7000-9000 rpm for 3-5 minutes, wash with methanol, dry at 40-60°C for 8-10 hours, and finally treat in a hydrogen atmosphere at 300-400°C for 2-4 hours to obtain a MOF material; Step B2. reacting pleuromutilin and a modifying agent at 40-50° C. for 3-5 h to obtain activated pleuromutilin; Step B3. Stir the MOF material and activated pleuromutilin at 60-70° C. for 20-24 hours. After the reaction is completed, separate and purify to obtain modified pleuromutilin B.

7. The composition of pleuromutilin and kasugamycin according to claim 6, characterized in that In step B1, the ligand is 1,2,4-triazole, and the concentration of the methanol solution of the ligand is 0.3-0.5 mol / L; the concentration of the methanol solution of zinc nitrate is 0.2-0.4 mol / L; The molar ratio of the ligand to zinc nitrate in step B1 is 1-1.5:4-6; The molar ratio of pleuromutilin to the modifying agent in step B2 is 1-1.8:3-6; The modifying agent in step B2 is any one of sodium dodecyl sulfate, polyethylene glycol, 3-aminopropyltriethoxysilane, glutaraldehyde, citric acid and ethylenediaminetetraacetic acid; The mass ratio of the MOF material to the activated pleuromutilin in step B3 is 1.2-1.5:0.7-0.

9.

8. The composition of pleuromutilin and kasugamycin according to claim 1, characterized in that The preparation process of the modified pleuromutilin C is as follows: Step C1. drying the biochar at 80-100° C. for 4-6 hours, grinding the dried biochar, and finally passing through a 100-120 mesh sieve to obtain pretreated biochar; Step C2. Add a solvent to a reaction vessel, then dissolve pleuromutilin in the solvent, stir evenly to form a pleuromutilin solution, then add the pretreated biochar, stir and mix, and react at 60-80° C. for 10-12 hours; Step C3. After the reaction is completed, the reaction mixture is filtered, the solid product is washed, and finally dried at 60-80° C. for 4-6 hours to obtain modified pleuromutilin C.

9. The composition of pleuromutilin and kasugamycin according to claim 8, characterized in that The solvent in step C2 is any one of methanol, ethanol and dichloromethane; The usage ratio of pleuromutilin, solvent and pretreated biochar in step C2 is 1-2 g: 200-300 mL: 8-12 g.

10. The method for preparing the composition of pleuromutilin and kasugamycin according to any one of claims 1 to 9, characterized in that: The following steps are involved: The surfactant and the antifreeze agent are dissolved in deionized water, the active ingredient and the thickener are added, the mixture is evenly mixed and then pumped into a sand grinder for grinding, and a defoamer is added. When D90 is less than 8 μm, stirring is stopped, and the mixture is filtered to obtain a composition of pleuromutilin and kasugamycin; The surfactant is any one of sodium diphenylmethanesulfonate, sodium naphthalenesulfonate formaldehyde condensate and sodium p-toluenesulfonate; The antifreeze agent is sodium chloride; The thickener is magnesium aluminum silicate SF-40; The defoaming agent is polydimethylsiloxane.

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