Pleuromutilin derivative containing thioether side chain and application of pleuromutilin derivative in prevention and treatment of plant diseases

Abstract

The invention provides a pleuromutilin derivative containing a thioether side chain and application of the pleuromutilin derivative in prevention and treatment of plant diseases. The pleuromutilin derivative is a compound represented by a formula I, or a stereoisomer, a tautomer, an isotope derivative and a pesticide acceptable salt thereof. The pleuromutilin derivative disclosed by the invention shows excellent bacteriostatic activity on phytopathogens such as pathogenic bacteria, and particularly shows a remarkable inhibition effect on xanthomonas pathogenic bacteria and Releiella pathogenic bacteria, and particularly on Xanthomonas oryzae pv. Oryzae, Xanthomonas citri pv. Citri and Pseudomonas solanacearum pv. Lanceolatifolia pv. Lanceolatifolia pv. Lanceolatifolia pv. Lanceolatifolia. The pleuromutilin derivative is low in preparation difficulty, and raw materials are cheap and easy to obtain. Therefore, the compound has further development value and is expected to be developed into a novel agricultural bactericide. Formula I.

Description

Technical Field

[0001] This invention belongs to the field of agriculture, specifically relating to a truncated pleurotin derivative containing a sulfide side chain and its application in the prevention and control of plant diseases. Background Technology

[0002] Plant pathogens are one of the main causes of crop diseases. These pathogens can invade tissues through plant wounds or natural openings, leading to local or systemic infections and posing a serious threat to agricultural production. Their transmission routes include rainwater splashing, insect vectors, and agricultural operations, often causing various diseases such as bacterial wilt, soft rot, and citrus Huanglongbing (HLB), resulting in yield reductions of 20%–70%, and in severe cases, even total crop failure. Currently, conventional chemical fungicides can inhibit the spread of pathogens to some extent, but they suffer from high toxicity, significant environmental residues, and potential harm to the ecosystem and human and animal health. Therefore, developing new, highly efficient, low-toxicity, and low-residue green pesticides has become an urgent need for plant disease control.

[0003] Natural products, due to their good environmental compatibility, low residue, and renewability, are gradually becoming an important source for pesticide research and development in the context of green agriculture. Terpenoids, as a class of natural metabolites widely found in plants and fungi, possess diverse structures, broad biological activities, and good environmental compatibility. They also typically exhibit low toxicity or easy degradation, significantly reducing the negative impacts of chemical pesticides on ecosystems. Pleuromutilin, a natural terpenoid derived from fungi, has shown great potential in agricultural antifungal applications due to its unique mechanism of action, providing important insights for the development of novel, green, and efficient biological pesticides.

[0004] The present invention aims to modify the structure of truncated pleurotin side chains to provide derivatives with excellent inhibitory activity against plant pathogens and with the potential to be developed into novel anti-plant pathogen drugs. Summary of the Invention

[0005] The purpose of this invention is to obtain a truncated pleurotin derivative that has excellent inhibitory activity against plant pathogens and can be used to prevent and control plant diseases.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a truncated pleurotin derivative containing a sulfide side chain, characterized in that the truncated pleurotin derivative is a compound represented by Formula I as shown below, or a stereoisomer, tautomer, isotopic derivative thereof, or a pesticide-acceptable salt thereof:

[0007] Formula I, Wherein, R is an optionally substituted alkyl, optionally substituted aryl, or optionally substituted heteroaryl; the substituent on the aryl or heteroaryl is selected from one or more of halogen, amino, hydroxyl, nitro, cyano, mercapto, optionally substituted alkyl, optionally substituted alkyloxy, optionally substituted alkylthio, or optionally substituted alkylamino. The optionally substituted alkyl, optionally substituted alkyloxy, optionally substituted alkylthio, or optionally substituted alkylamine substituents may be selected from one or more of the following groups: halogen, amino, hydroxyl, nitro, cyano, mercapto.

[0008] In some embodiments, the alkyl group is a C1-10 alkyl group, preferably a C1-8 alkyl group, a C1-6 alkyl group, a C1-4 alkyl group, a C2-C6 alkyl group, or a C3-C6 alkyl group.

[0009] In some embodiments, the aryl group is a C6-10 aryl group, preferably phenyl or naphthyl (such as 1-naphthyl or 2-naphthyl).

[0010] In some embodiments, the heteroaryl group is a 5-10 member heteroaryl group.

[0011] In some embodiments, the heteroaryl group contains 1-3 heteroatoms selected from N, O, and S.

[0012] In some embodiments, the heteroaryl group is a 5-10 member heteroaryl group containing 1-3 heteroatoms selected from N, O, and S; preferably, it is a 5-6 member heteroaryl group containing 1-2 heteroatoms selected from N, O, and S (such as furanyl, thiophene, pyrrole, thiazolyl, oxazolyl, isoxazolyl, pyrazolyl, imidazole, pyridinyl, pyranyl, pyrazinyl, pyrimidinyl, etc.), or a 9-10 member heteroaryl group containing 1-2 heteroatoms selected from N, O, and S (such as indolyl, benzothiazolyl, benzoxazolyl, benzimidazolyl, benzofuranyl, benzothiophene, quinolinyl, isoquinolinyl, purinyl, pteridinyl, etc.); more preferably, it is 2-thiophene, 2-pyridinyl, 2-benzimidazolyl, 2-benzothiazolyl, or 2-benzoxazolyl.

[0013] In some embodiments, R is a C1-10 alkyl, optionally substituted C6-10 aryl, or optionally substituted 5-10 heteroaryl. Preferably, R is an aryl or heteroaryl group optionally substituted with a halogen, amino, hydroxyl, nitro, cyano, mercapto, C1-6 alkyl, C1-6 haloalkyl, hydroxy-substituted C1-6 alkyl, C1-6 alkyloxy, C1-6 alkylthio, or C1-6 alkylamino.

[0014] In some embodiments, R is a C1-8 alkyl group, an optionally substituted phenyl group, an optionally substituted naphthyl group, or an optionally substituted 5-10 heteroaryl group containing 1-3 heteroatoms selected from N, O, and S.

[0015] In some embodiments, R is a C3-6 alkyl group, optionally substituted phenyl group, optionally substituted thiophene group, optionally substituted pyridyl group, optionally substituted benzimidazolyl group, optionally substituted benzothiazolyl group, optionally substituted benzoxazolyl group.

[0016] In some embodiments, R is n-pentyl, n-hexyl, or optionally phenyl, thiophene, pyridyl, benzimidazolyl, benzothiazolyl, or benzoxazolyl substituted with halogen, amino, or C1-6 alkyl.

[0017] In some embodiments, the halogen is F, Cl, or Br.

[0018] Specifically, the compound represented by Formula I is one of the following compounds JD-S-1 to JD-S-16: .

[0019] In a second aspect, this application provides a method for preparing the truncated pleurotin derivative, as shown in reaction formula 1: .

[0020] In some embodiments, the first step involves reacting p-toluenesulfonyl chloride in the presence of a base, such as an organic base (e.g., triethylamine, diisopropylethylamine), in an organic solvent at room temperature.

[0021] In some embodiments, the second step is carried out in the presence of a base, such as a reflux reaction in an organic solvent in the presence of an inorganic base (e.g., sodium hydroxide, potassium hydroxide).

[0022] In a third aspect, this application also provides a bactericidal composition comprising at least one of the truncated pleurotin derivatives described in the first aspect of this application as an active ingredient; and optionally a pesticide-acceptable carrier and / or adjuvant.

[0023] The bactericidal composition of this application can be applied in the form of a formulation, wherein the truncated pleurotin derivative is dissolved or dispersed in a carrier as an active component or formulated into a formulation for easier dispersion when used as a bactericidal composition. The bactericidal composition can be formulated into various liquid formulations, such as soluble powders, dispersible liquids, emulsifiable concentrates, suspensions, aqueous suspensions, microemulsions, emulsions, water-in-oil emulsions, and water-dispersible granules.

[0024] The bactericidal composition of this application may contain one or more other insecticides, fungicides, herbicides, plant growth regulators or fertilizers.

[0025] This application also discloses the application of the truncated pleurotin derivatives described in the first aspect or the bactericidal composition described in the third aspect in the prevention and control of plant diseases, for controlling plant diseases caused by plant pathogens; preferably for use in agriculture, forestry, horticulture and health fields.

[0026] In one set of embodiments, an effective amount of the truncated pleurotin derivative as described above, or the fungicide composition as described above, is applied to plants, plant propagation materials, or subsequently grown plant organs and cultivation media, cultivation materials, or cultivation spaces; or an effective amount of the truncated pleurotin derivative as described above, or the fungicide composition as described above, is used to prevent or control pathogens on wood roots.

[0027] Preferably, an effective amount of the truncated pleurotin derivative as described above or the bactericidal composition as described above is applied to the leaves, stems, roots, seeds, or soil.

[0028] In one set of embodiments, the plant pathogen is preferably a pathogenic bacterium, including but not limited to xanthomonas and Ralstonia species. Preferably, the plant pathogen is rice bacterial blight fungus, rice bacterial leaf streak fungus, citrus canker fungus, cruciferous black rot fungus, or bacterial wilt fungus (also known as Ralstonia solanacearum).

[0029] The truncated pleurotin derivatives described in the first aspect of this application or the bactericidal compositions described in the third aspect can be used in conjunction with one or more other insecticides, fungicides, herbicides, plant growth regulators, or fertilizers.

[0030] The beneficial effects of this invention are as follows: This invention synthesizes a class of truncated pleurotin derivatives containing thioether side chains and systematically evaluates their inhibitory activity against a variety of plant pathogens.

[0031] Experimental results show that the truncated pleurotin derivatives described in this application exhibit excellent antibacterial activity against plant pathogens, such as pathogenic bacteria, especially against Xanthomonas and Ralstonia species, and particularly against rice bacterial blight, citrus canker, and Ralstonia solanacearum.

[0032] Analysis showed that some compounds in this application exhibited inhibition rates of over 95% against rice bacterial blight, citrus canker, and Ralstonia solanacearum at a concentration of 100 μg / mL, which was significantly better than the inhibitory activity of truncated pleurotin (MIC=25 μg / mL).

[0033] The truncated pleurotin derivatives described in this application are easy to prepare, and the raw materials are inexpensive and readily available. Therefore, these compounds have value for further development and are expected to be developed into novel agricultural fungicides. Detailed Implementation

[0034] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0035] 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.

[0036] Before describing the invention in detail, it should be understood that the terminology used herein is for describing particular embodiments only and is not intended to limit the scope of the invention, which is defined only by the appended claims. For a more complete understanding of the invention described herein, the following terms are used, and their definitions are as follows. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0037] Features described or illustrated as part of one or more embodiments may be used in another or more embodiments to produce further embodiments.

[0038] The “truncated pleurotin derivative” described in this application includes compounds represented by Formula I, or their stereoisomers, tautomers, isotopic compounds, and pesticide-acceptable salts; and the preferred embodiments specifically described. The stereoisomers, tautomers, isotopic compounds, or pesticide-acceptable salts of the compounds are obtained by conventional techniques in the art and exert the same or similar effects in vitro and in vivo through substantially the same mechanism of action as the compounds.

[0039] Unless otherwise stated, “optional substitution” means that the hydrogen on the substituted group is not substituted or that one or more substituted sites of the substituted group are independently substituted by a substituent, which is independently selected from one or more of deuterium, halogen, amino, hydroxyl, nitro, cyano, mercapto, oxo, optionally substituted alkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted cycloalkyl, optionally substituted heterocycloalkyl, optionally substituted alkyloxy, optionally substituted alkylthio, optionally substituted alkylamine; the substituent on the aryl, heteroaryl, cycloalkyl, and heterocycloalkyl groups may be one or more of deuterium, halogen, amino, hydroxyl, nitro, cyano, mercapto, oxo, optionally substituted alkyl, optionally substituted alkyloxy, optionally substituted alkylthio, optionally substituted alkylamine; the substituent on the alkyl group is selected from one or more of deuterium, halogen, amino, hydroxyl, nitro, cyano, and mercapto; when the substituent is selected as “oxo”, it means that two hydrogen atoms at the same substitution position are replaced by an oxygen atom.

[0040] The terms “alkyloxy”, “alkylthio”, and “alkylamine” refer to -O-alkyl, -S-alkyl, -NH-alkyl, or dialkylamine, respectively.

[0041] The terms "alkyloxy", "alkylthio", "alkylamine", "hydroxy-substituted alkyl", "halogenated alkyl", and "alkyl" refer to a monovalent saturated aliphatic hydrocarbon group, preferably containing 1-20, 1-18, 1-16, 1-12, or 1-10 carbon atoms, more preferably 1-8 carbon atoms (C1-8 alkyl) straight-chain or branched groups (the number of carbon atoms is between 1 and 8, specifically 1, 2, 3, 4, 5, 6, 7, or 8), more preferably containing 1-6 carbon atoms (i.e., C1-6 alkyl, the number of carbon atoms is between 1 and 6, specifically 1, 2, 3, 4, 5, or 6). Examples include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, neopentyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, 1-ethylpropyl, 2-methylbutyl, 3-methylbutyl, n-hexyl, n-heptyl, n-octyl, etc. The term "aryl" refers to a monocyclic or bicyclic aromatic carbocyclic system containing 6-10 carbon atoms. Examples of aryl groups include phenyl and naphthyl groups, such as 1-naphthyl, 2-naphthyl, 3-naphthyl, and 4-naphthyl.

[0042] The term "heteroaryl" refers to an aromatic monocyclic or polycyclic system containing a 5-14 member structure, preferably a 5-10 member structure or a 6-10 member structure, more preferably a 5-6 member structure, wherein one, two, three, four or more ring atoms are heteroatoms and the remaining atoms are carbon atoms, the heteroatoms being independently selected from O, N or S, and the number of heteroatoms is preferably one, two, three or four. A heteroaryl group can be an aromatic monocyclic group containing one or two 5-6 member structures selected from N, S, or O, or an aromatic bicyclic group containing one or two 9-10 member structures selected from N, S, or O. Examples of heteroaryl groups include, but are not limited to, furanyl, thiophene, oxazolyl, thiazolyl, isoxazolyl, oxadiazolyl, thiazolyl, pyrroloyl, pyrazolyl, imidazoleyl, triazolyl, tetrazolyl, pyridyl, pyranyl, pyrimidinyl, pyrazinyl, pyridazinyl, morpholinyl, thiodiazolyl, triazinyl, phthalazinyl, quinolinyl, isoquinolinyl, pteridinyl, purine, indoleyl, isoindoleyl, indazoleyl, benzofuranyl, benzothiophene, benzopyridyl, benzopyrimidinyl, benzopyrazinyl, benzoimidazolyl, benzophthalazinyl, pyrrolo[2,3-b]pyridyl, imidazo[1,2-a]pyridyl, pyrazolo[1,5-a]pyridyl, pyrazolo[1,5-a]pyrimidinyl, imidazo[1,2-b]pyridazinyl, [1 [2,4]triazolo[4,3-b]pyridazinyl, [1,2,4]triazolo[1,5-a]pyrimidinyl, [1,2,4]triazolo[1,5-a]pyridinyl, pyridin-1-yl, pyridin-2-yl, pyridin-3-yl, pyridin-4-yl, quinoline-2-yl, quinoline-3-yl, quinoline-4-yl, quinoline-5-yl, quinoline-6-yl, quinoline-7-yl, quinoline-8-yl, etc.

[0043] The term "cycloalkyl" refers to a saturated monocyclic, bicyclic, or tricyclic system containing 3-12 carbon atoms, wherein the monocyclic, bicyclic, or tricyclic ring does not contain an aromatic ring, including bridged cycloalkyl, spirocyclic, and fused cycloalkyl groups. Preferably, it contains 3-10 carbon atoms (C3-10 cycloalkyl), more preferably 3-8 carbon atoms (C3-8 cycloalkyl), 3-6 carbon atoms (C3-6 cycloalkyl), 4-6 carbon atoms (C4-6 cycloalkyl), or 5-6 carbon atoms (C5-6 cycloalkyl). Examples include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.

[0044] The term "heterocyclic alkyl" refers to a saturated monocyclic, bicyclic, or polycyclic cyclic hydrocarbon group, preferably containing 3-12 ring atoms, wherein one, two, three, or more ring atoms are selected from N, O, or S, and the remaining ring atoms are C, including bridged cyclic groups, spirocyclic groups, fused cyclic groups, etc. Preferably, it contains 3-10 ring atoms (3-10 membered heterocyclic alkyl), or 3-8 ring atoms (3-8 membered heterocyclic alkyl), or 3-6 ring atoms (3-6 membered heterocyclic alkyl), or 4-6 ring atoms (4-6 membered heterocyclic alkyl), or 5-6 ring atoms (5-6 membered heterocyclic alkyl). The number of heteroatoms is preferably 1-4, more preferably 1-3 (i.e., 1, 2, or 3). The heterocyclic alkyl group may be a 5-6 membered monocyclic heterocyclic alkyl group containing 1-2 N or O atoms. Examples of heterocyclic alkyl groups include pyrrolidinyl, imidazoalkyl, tetrahydrofuranyl, piperidinyl, piperazinyl, tetrahydropyranyl, azircyclopropane, oxacyclopropane, thiohexacyclopropane, azircyclobutane, oxacyclobutane, thiohexacyclobutane, oxacyclohexane, morpholinyl, thiomorpholinyl, dioxane, dithiohexyl, oxazolyl, thiazoalkyl, pyrazolyl, imidazolinidine, tetrahydrofuran-1-yl, tetrahydrofuran-2-yl, tetrahydrofuran-3-yl, tetrahydropyran-1-yl, tetrahydropyran-2-yl, tetrahydropyran-3-yl, tetrahydropyran-4-yl, piperidin-1-yl, piperidin-4-yl, etc.

[0045] The term "halogen" refers to F, Cl, Br, and I. The term "stereoisomer" refers to isomers resulting from different spatial arrangements of atoms in a molecule, including configurational isomers and conformational isomers. Configurational isomers include geometric isomers (or cis-trans isomers) and optical isomers (including enantiomers and diastereomers). Geometric isomers may be present in this compound. Optical isomers refer to substances with identical molecular structures and similar physicochemical properties, but different optical rotations. The compounds of this invention may contain asymmetrically substituted carbon atoms in the R or S configuration, wherein the terms "R" and "S" are as defined in IUPAC 1974 Recommendations for Section E, Fundamental Stereochemistry, Pure Appl. Chem. (1976) 45, 13-10. Compounds with asymmetrically substituted carbon atoms (having equal numbers of R and S configurations) are racemic at those carbon atoms. Having an excess of atoms in one configuration (relative to another) results in a higher quantity of that configuration, preferably an excess of about 85%-90%, more preferably an excess of about 95%-99%, and even more preferably an excess greater than about 99%. Accordingly, the present invention includes racemic mixtures, relative and absolute optical isomers, and mixtures of relative and absolute optical isomers.

[0046] The term "tautomer" refers to structural isomers with different energies that can interconvert through a low energy barrier. If tautomerism is possible (e.g., in solution), chemical equilibrium can be achieved for the tautomers. For example, proton tautomers (also called proton transfer tautomers) involve interconversions via proton migration, such as keto-enol isomerization and imine-enamine isomerization. Valence tautomers involve interconversions via the rearrangement of some bonding electrons.

[0047] The term "isotope derivative" refers to compounds of the present invention that can exist in an isotopically traced or enriched form, containing one or more atoms whose atomic weights or mass numbers differ from the atomic weights or mass numbers of the most abundant atoms found in nature. Isotopes can be radioactive or non-radioactive. Isotopes of atoms such as hydrogen, carbon, phosphorus, sulfur, fluorine, chlorine, bromine, and iodine include, but are not limited to: 2 H, 3 H, 13 C, 14 C, 15 N, 18 O, 32 P, 35 S, 18 F, 36 Cl, 80 Br and 125 I. Compounds containing these and / or other isotopes are within the scope of this invention. The isotopically labeled compounds of this invention can be prepared using general methods well known to those skilled in the art.

[0048] The term "pesticide-acceptable salt" refers to a salt obtained by reacting the truncated pleurotin derivative of this application with a chemically acceptable acid, wherein the chemically acceptable acid can be an inorganic acid or an organic acid; the pesticide-acceptable salt can also be a salt obtained by reacting the truncated pleurotin derivative of this application with a chemically acceptable base, wherein the chemically acceptable base can be an inorganic base or an organic base.

[0049] The term "pesticide-acceptable carrier" includes, but is not limited to, surfactants, including ionic and nonionic surfactants. The surfactants include emulsifiers, dispersants, or wetting agents. Specifically, the emulsifiers may be polyoxyethylene fatty acid esters, polyoxyethylene fatty alcohol ethers, polyoxyethylene fatty amines, and commercially available emulsifiers; the dispersants include sodium lignosulfonate, dispersing agents, calcium lignosulfonate, or methylnaphthalenesulfonate formaldehyde condensate, etc.; the wetting agents include sodium lauryl sulfate, sodium dodecylbenzenesulfonate, or alkylnaphthalenesulfonate, etc. The pesticide-acceptable carrier includes solid carriers and / or liquid carriers. Preferably, the solid carrier includes natural or synthetic clays and silicates, such as natural silica and diatomaceous earth; magnesium silicate, such as talc; magnesium aluminum silicate, such as kaolinite, montmorillonite, and mica; white carbon black, calcium carbonate, light calcium carbonate; calcium sulfate; limestone; sodium sulfate; and amine salts such as ammonium sulfate and hexamethylenediamine. Preferably, the liquid carrier comprises water and an organic solvent; when water is used as a solvent or diluent, the organic solvent can be used as an auxiliary agent or antifreeze additive. Preferably, the organic solvent includes aromatic hydrocarbons (e.g., benzene, xylene, or toluene), chlorinated hydrocarbons (e.g., chlorobenzene, vinyl chloride, chloroform, or dichloromethane), aliphatic hydrocarbons (e.g., petroleum fractions, cyclohexane, or light mineral oil), alcohol solvents (e.g., isopropanol, butanol, ethylene glycol, glycerol, or cyclohexanol), ether solvents, ester solvents, ketone solvents (e.g., acetone, cyclohexanone, or N-methylpyrrolidone), or dimethylformamide, etc.

[0050] The bactericide composition can be formulated by mixing the active component with a liquid carrier and / or a solid carrier, and by adding surfactants (such as emulsifiers, dispersants, stabilizers, and wetting agents), as well as other additives (such as adhesives, defoamers, and oxidants).

[0051] The present invention will be further illustrated below with reference to specific embodiments; however, these embodiments do not limit the scope of the invention. Unless otherwise stated, all reactants used in the embodiments are commercially available or can be prepared by methods known in the literature or as detailed in the description; the instruments and equipment used in the synthesis experiments and product analysis are all conventional instruments and equipment commonly used in organic synthesis. Unless otherwise specified, the experimental methods described in the following embodiments are conventional methods.

[0052] Example 1: Preparation of compounds JD-S-1~JD-S-16

[0053] Synthesis of Intermediate I: Triethylamine (7.3 mL, 53.6 mmol) was slowly added to a mixture of truncated pleurotin (10 g, 26.4 mmol), p-toluenesulfonyl chloride (5.5 g, 29.1 mmol), and dichloromethane (40 mL). The mixture was stirred at room temperature for 24 h. The reaction mixture was extracted with dichloromethane, the organic phases were combined, dried over sodium sulfate, and concentrated under vacuum. The crude mixture was purified by silica gel column chromatography to give Intermediate 1 as a white solid.

[0054] Synthesis of compounds JD-S-1 to JD-S-16: Intermediate 1 (1.1 g, 2.06 mmol) was dissolved in 15 mL of ethyl acetate, and thiol HS-R (2.48 mmol) and 5 mL of 20% sodium hydroxide solution were added. The mixture was heated to reflux at 70°C for 3 h. The mixture was extracted with ethyl acetate, and the combined organic phases were dried over anhydrous Na₂SO₄ and concentrated. The resulting product was purified by silica gel column chromatography to obtain the target compounds.

[0055] Structural characterization parameters of compounds JD-S-1 to JD-S-16 are shown in Table 1. Table 1. Structural characterization parameters of compounds JD-S-1 to JD-S-16

[0056] Example 2: Determination of the anti-agricultural pathogenic bacteria activity of truncated pleurotin derivatives and its results 1) Test reagents: truncated pleurotin derivatives JD-S-1~JD-S-16.

[0057] 2) Test strains: PXO99A, pathogen of rice bacterial blight, and pathogen of citrus canker. Xanthomonas axonopodis pv. Citri and bacterial wilt pathogen Pseudomonas solanacearum Provided by Gansu Academy of Agricultural Sciences.

[0058] 3) Antibacterial activity test: The bacterial strains used in this experiment were cryopreserved in the laboratory at -80℃ with 30% glycerol. The cryopreserved strains were removed and streaked onto NB solid medium (beef extract: 3 g, peptone: 5 g, yeast extract: 1 g, sucrose: 10 g, agar: 15 g, distilled water: 1 L, pH 7.0; sterilized at 121℃ for 20 min), and incubated at 28℃ until single colonies appeared. Single colonies from the solid medium were transferred to NB liquid medium (beef extract: 3 g, peptone: 5 g, yeast extract: 1 g, sucrose: 10 g, distilled water: 1 L; sterilized at 121℃ for 20 min) and cultured on a shaker at 28℃ and 180 rpm until the logarithmic growth phase. The strains in the logarithmic growth phase were diluted with NB liquid medium to approximately 10... 6 CFU / mL was prepared for use. The compounds were dissolved separately in DMSO, added to liquid culture medium, and mixed thoroughly to prepare a drug-containing liquid culture medium with a concentration of 200 μg / mL. 50 μL of the drug-containing culture medium and the same volume of approximately 10... 6 CFU / mL bacterial culture was added to the wells of a 96-well plate, resulting in a final drug concentration of 100 μg / mL. A control of 100 μL of bacterial culture containing an equal amount of DMSO was used. The 96-well plates were incubated at 28℃ for 24–48 h until bacterial growth was observed in the control group. The OD value (OD) of the bacterial culture in each well was measured using a microplate reader. 600 In addition, the OD values ​​of 100 μL of liquid culture medium and a 100 μg / mL drug concentration were measured to correct for the OD values ​​caused by the culture medium and the drug itself. The formulas for calculating the corrected OD value and inhibition rate are as follows: Corrected OD value = OD value of bacterial culture medium - OD value of sterile culture medium; Inhibition rate = (OD value of bacterial suspension in control medium after correction - OD value of bacterial suspension in drug-containing medium after correction) / OD value of bacterial suspension in control medium after correction × 100% The drug-containing liquid culture medium was diluted in 96-well plates using a two-fold dilution method to obtain a series of 50 μL drug-containing media. The inhibition rates corresponding to these concentrations were then determined using the same experimental method described above. All experiments were performed in triplicate, and the MIC values ​​of the compound were measured. The inhibitory effect data of the truncated pleurotin derivative described in this application are shown in Table 2.

[0059] Table 2. In vitro antibacterial activity of truncated pleurotin derivatives JD-S-1~JD-S-16 against plant pathogenic bacteria.

[0060] As shown in Table 2, the truncated pleurotin derivatives JD-S-1 to JD-S-16 prepared in this application exhibited varying degrees of inhibitory activity against three plant pathogenic bacteria. This series of derivatives generally showed inhibitory effects against *Rhizoctonia solani* (bacterial blight of rice) and *Rhizoctonia solani* (citrus canker). JD-S-12 and JD-S-16 showed particularly good inhibitory effects against all three plant pathogenic bacteria. JD-S-5, JD-S-7, and JD-S-12 achieved inhibition rates exceeding 95% against *Rhizoctonia solani*, while JD-S-1, JD-S-7, JD-S-11, JD-S-12, and JD-S-16 achieved inhibition rates exceeding 95% against *Rhizoctonia solani*. JD-S-12 and JD-S-16 also achieved inhibition rates exceeding 95% against *Rhizoctonia solani*. JD-S-12 and JD-S-16 showed MIC values ​​of 1.56–3.12 μg / mL against rice bacterial blight and citrus canker, which were significantly better than the inhibitory activity of truncated pleurotin (MIC=25 μg / mL). Therefore, these compounds have the potential for further development and are expected to be developed into novel agricultural antibacterial agents.

[0061] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0062] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this invention will not describe the various possible combinations separately. As long as they do not violate the spirit of this invention, they should also be regarded as the content disclosed by this invention.

Claims

1. A truncated pleurotin derivative containing a sulfide side chain, characterized in that, The truncated pleurotin derivative is a compound represented by Formula I as shown below, or its stereoisomers, tautomers, isotopic derivatives, and pesticide-acceptable salts: Formula I, Wherein, R is an optionally substituted alkyl, optionally substituted aryl, or optionally substituted heteroaryl; the substituent on the aryl or heteroaryl is selected from one or more of halogen, amino, hydroxyl, nitro, cyano, mercapto, optionally substituted alkyl, optionally substituted alkyloxy, optionally substituted alkylthio, or optionally substituted alkylamino. The optionally substituted alkyl, optionally substituted alkyloxy, optionally substituted alkylthio, or optionally substituted alkylamine substituents may be selected from one or more of the following groups: halogen, amino, hydroxyl, nitro, cyano, mercapto.

2. The truncated pleurotin derivative according to claim 1, characterized in that, R is a C1-10 alkyl, optionally substituted C6-10 aryl, optionally substituted 5-10 heteroaryl; preferably, R is an aryl or heteroaryl group optionally substituted with halogen, amino, hydroxyl, nitro, cyano, mercapto, C1-6 alkyl, C1-6 haloalkyl, hydroxy-substituted C1-6 alkyl, C1-6 alkyloxy, C1-6 alkylthio, or C1-6 alkylamino.

3. The truncated pleurotin derivative according to claim 2, characterized in that, R is a C1-8 alkyl group, optionally substituted phenyl group, optionally substituted naphthyl group, optionally substituted 5-10 heteroaryl group containing 1-3 heteroatoms selected from N, O, S; preferably, R is a C3-6 alkyl group, optionally substituted phenyl group, optionally substituted thiophene group, optionally substituted pyridyl group, optionally substituted benzimidazolyl group, optionally substituted benzothiazolyl group, optionally substituted benzoxazolyl group.

4. The truncated pleurotin derivative according to claim 3, characterized in that, R is n-pentyl, n-hexyl, or optionally substituted with halogen, amino, C1-6 alkyl, phenyl, thiophene, pyridyl, benzimidazolyl, benzothiazolyl, or benzoxazolyl.

5. The truncated pleurotin derivative according to any one of claims 1-4, characterized in that, The halogens are F, Cl, and Br.

6. The truncated pleurotin derivative according to claim 1, characterized in that, The compound represented by Formula I is one of the following compounds JD-S-1 to JD-S-16: 。 7. A bactericidal composition, characterized in that, It contains at least one of the truncated pleurotin derivatives as described in any one of claims 1-6 as an active ingredient; and optionally a pesticide-acceptable carrier and / or adjuvant.

8. The use of the truncated pleurotin derivative according to any one of claims 1-6 or the fungicidal composition according to claim 7 in the prevention and control of plant diseases, characterized in that, It is used to control plant diseases caused by plant pathogens.

9. The application according to claim 8, characterized in that, The plant pathogens mentioned are pathogenic bacteria.

10. The application according to claim 9, characterized in that, The plant pathogens are pathogenic bacteria of the genera Xanthomonas and Ralstonia; preferably, the plant pathogens are rice bacterial blight pathogens, rice bacterial leaf streak pathogens, citrus canker pathogens, cruciferous black rot pathogens, and bacterial wilt pathogens.

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