A thiophene-based agricultural fungicide

Abstract

The present application provides a novel structure of thiophene compound, the compound has significant inhibitory effect on spore germination and appressorium formation of various plant pathogenic fungi and oomycetes (such as Pyricularia oryzae, Colletotrichum gloeosporioides, Gibberella, Phytophthora, Phytophthora capsici), which can be used for preventing and treating plant diseases caused by fungi and / or oomycetes.

Description

Technical Field

[0001] This invention belongs to the field of fungicide technology, specifically relating to a thiophene-based agricultural fungicide. Background Technology

[0002] Most plant diseases are caused by fungi and oomycetes. A single plant may be affected by several or even dozens of different fungi and oomycetes causing diseases. For example, rice diseases such as sheath blight, rice blast, rice false smut, sesame leaf spot, and bakanae disease; wheat diseases such as Fusarium head blight, stripe rust, stem rust, leaf rust, and root rot; and corn diseases such as large leaf spot, small leaf spot, stem base rot, rust, sheath blight, Curvularia leaf spot, head smut, and powdery mildew are all caused by fungi. Potato late blight, soybean Phytophthora blight, pepper Phytophthora blight, grape downy mildew, and cucumber downy mildew are caused by oomycetes.

[0003] Chemical fungicides, characterized by their economy and high efficiency, have long been the preferred method for controlling crop diseases. Commonly used fungicides include cyazofamid, chlorothalonil, pyraclostrobin, chlorothalonil, thiophanate-methyl, carbendazim, azoxystrobin, boscalid, prochloraz, and mancozeb. However, these fungicides have exhibited a series of problems with increasing years of use. For example, they show varying degrees of toxicity to non-target organisms in the farmland environment; their similar and singular modes of action lead to field resistance; and cross-resistance among fungicides of the same class is a serious problem. Therefore, the development of novel, green, and safe fungicides is an urgent need for safe production.

[0004] Plant pathogens must spread to the plant body to cause primary infection, and secondary infection can only occur between plants through transmission. Asexual spore dispersal is the primary mode of transmission. For example, when *Pyrophyte oryzae* and *Anthracnose* infect plants, spores adhere to the plant surface and germinate into germ tubes. Appressoria then form at the tips of these germ tubes, and under significant turgor pressure, infection nails differentiate from the base of the appressoria, invading the plant tissue and causing disease. Currently, there are very few fungicides on the pesticide market that specifically inhibit spore germination and appressoria formation; only tricyclazole prevents disease by inhibiting the maturation of pathogen appressoria. Therefore, developing inhibitors targeting pathogen spore germination and appressoria formation could provide a new avenue for the development of novel fungicides. Summary of the Invention

[0005] This invention provides a novel thiophene compound that significantly inhibits the germination of conidia and appressorium formation of *Pyrrosia oryzae*, exhibiting significant preventative and curative effects against rice blast and other diseases. Furthermore, this compound also demonstrates significant control effects against various other plant pathogenic fungi and oomycetes.

[0006] This invention provides a compound of formula (I), its stereoisomers, racemates, tautomers, isotope-labeled compounds, nitrogen oxides, agriculturally acceptable salts or esters, solvates, or solvates of agriculturally acceptable salts:

[0007] Formula (I) Among them, R a They are either the same or different, and are independently selected from H and C. 1-10 Alkyl, Halogenated C 1-10 Alkyl, C 1-10 Alkoxy, halogenated C 1-10 Alkoxy, CN, halogen; n is selected from 0, 1, 2, 3, or 4; R1 is selected from: H, halogen, CN, C 1-10 Alkyl, Halogenated C 1-10 Alkyl, C 1-10 Alkoxy, halogenated C 1-10 Alkyl group, -(CH2) 1-10 -S-CH3, -(CH2) 1-10 -CONH2、-(CH2) 1-10 -COOH, -CH2-C 6-15 Aryl or -CH2-5-15 heteroaryl; the -CH2-C 6-15 C in aryl and -CH2-5-15 heteroaryl groups 6-15 The aryl group and the 5-15 heteroaryl group are independently unsubstituted, or optionally substituted by one, two or more R groups. b Replace; the C 1-10 Alkyl, Halogenated C 1-10 Alkyl, C 1-10 Alkoxy, halogenated C 1-10 The alkoxy groups are independently unsubstituted, or optionally substituted by one, two or more R groups. b replace; R b Selected from H, hydroxyl, halogen, C 1-6 Alkyl, CN; R2 is selected from H, halogens, CN, and C. 6-15 Aryl, C 1-10 Alkyl, Halogenated C 1-10 Alkyl, C 1-10 Alkoxy, halogenated C 1-10 Alkoxy; R3 is selected from H, halogens, CN, and C. 2-10 alkenyl, C 1-10 Alkyl, Halogenated C 1-10 Alkyl, C 1-10 Alkoxy, halogenated C 1-10Alkoxy, C 6-15 Aryl or 5-15 heteroaryl groups; R4 is selected from H, halogen, CN, C. 1-10 Alkyl, Halogenated C 1-10 Alkyl, C 1-10 Alkoxy, halogenated C 1-10 Alkoxy, C 6-15 Aryl or 5-15 heteroaryl groups; R5 is selected from H, CN, halogen, aldehyde, C. 1-10 Alkyl, Halogenated C 1-10 Alkyl, C 1-10 Alkoxy, halogenated C 1-10 Alkoxy, -N(C) 1-10 Alkyl)2, C 3-12 Cycloalkyl, 3-12 membered heterocycloalkyl, C 6-15 Aryl or 5-15 heteroaryl groups; R6 is selected from H, CN, halogens, and C. 1-10 Alkyl, Halogenated C 1-10 Alkyl, C 1-10 Alkoxy, halogenated C 1-10 Alkyl group.

[0008] According to an embodiment of the present invention, R a They are either the same or different, and are independently selected from H and C. 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 1-6 Alkoxy, halogenated C 1-6 Alkoxy, CN, halogen (e.g., F, Cl, Br, I); preferably, R a They are either the same or different, and are independently selected from H and C. 1-6 Alkyl, Halogenated C 1-4 Alkyl, C 1-4 Alkoxy, halogenated C 1-4 Alkyl groups, CN, halogens (e.g., F, Cl, Br, I); exemplarily, R a They may be the same or different, and are independently selected from H, methyl, methoxy, CN, and halogens (e.g., F, Cl, Br, I).

[0009] According to an embodiment of the present invention, n is selected from 0, 1, 2, or 3.

[0010] According to an embodiment of the present invention, R1 is selected from: H, C 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 1-6 Alkoxy, halogenated C 1-6 Alkyl group, -(CH2) 1-6 -S-CH3, -(CH2) 1-6 -CONH2、-(CH2)1-6 -COOH, -CH2-C 6-12 Aryl or -CH2-5-12 heteroaryl; the -CH2-C 6-12 C in aryl and -CH2-5-12 heteroaryl groups 6-12 The aryl and 5-12 heteroaryl groups are independently unsubstituted, or optionally substituted by one, two or more R groups. b Replace; the C 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 1-6 Alkoxy, halogenated C 1-6 The alkoxy groups are independently unsubstituted, or optionally substituted by one, two or more R groups. b replace; Preferably, R b Selected from H, hydroxyl, and halogen; Preferably, R1 is selected from: H, C 1-4 Alkyl, Halogenated C 1-4 Alkyl, C 1-4 Alkoxy, halogenated C 1-4 Alkyl group, -(CH2) 1-4 -S-CH3, -(CH2) 1-4 -CONH2、-(CH2) 1-4 -COOH, -CH2-C 6-10 Aryl or -CH2-5-10 heteroaryl; the -CH2-C 6-10 C in aryl and -CH2-5-10 heteroaryl groups 6-10 The aryl group and the 5-10 heteroaryl group are independently unsubstituted, or optionally substituted by one, two or more R groups. b Replace; the C 1-4 Alkyl, Halogenated C 1-4 Alkyl, C 1-4 Alkoxy, halogenated C 1-4 The alkoxy groups are independently unsubstituted, or optionally substituted by one, two or more R groups. b replace; For example, R1 is selected from: H, methyl, propyl (e.g., isopropyl) ), butyl (e.g., isobutyl) -CH2CH2-S-CH3 ( ), benzyl ( -CH(CH3)OH ), -CH2-phenyl-OH ( -CH2CH2-CONH2 ( -CH2CH2-COOH ), -CH2-imidazolium (e.g.) ), -CH2-indole (e.g.) ).

[0011] According to an embodiment of the present invention, R2 is selected from H, halogens, and C. 6-12 Aryl, C 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 1-6 Alkoxy, halogenated C 1-6 Alkoxy group; preferably, R2 is selected from H, halogen, C 6-10 Aryl, C 1-4 Alkyl, Halogenated C 1-4 Alkyl, C 1-4 Alkoxy, halogenated C 1-4 Alkoxy; for example, R2 is selected from: H, methyl, phenyl.

[0012] According to an embodiment of the present invention, R3 is selected from H, halogen, CN, and C. 2-6 alkenyl, C 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 1-6 Alkoxy, halogenated C 1-6 Alkoxy, C 6-12 Aryl or 5-12 heteroaryl; preferably, R3 is selected from H, halogen, CN, C. 2-4 alkenyl, C 1-4 Alkyl, Halogenated C 1-4 Alkyl, C 1-4 Alkoxy, halogenated C 1-4 Alkoxy, C 6-10 Aryl or 5-10 heteroaryl; exemplarily, R3 is selected from: H, CN, vinyl ( ), pyrazolyl (e.g.) ).

[0013] According to an embodiment of the present invention, R4 is selected from H, halogens, and C. 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 1-6 Alkoxy, halogenated C 1-6 Alkoxy, C 6-12 Aryl or 5-12 heteroaryl; preferably, R4 is selected from H, halogen, C 1-4 Alkyl, Halogenated C 1-4 Alkyl, C 1-4 Alkoxy, halogenated C 1-4 Alkoxy, C 6-10 Aryl or 5-10 heteroaryl; exemplarily, R4 is selected from: H, halogens (e.g., F, Cl, Br, I), pyridyl (e.g., ... ).

[0014] According to an embodiment of the present invention, R5 is selected from H, halogen, aldehyde, C.1-6 Alkyl, Halogenated C 1-6 Alkyl, C 1-6 Alkoxy, halogenated C 1-6 Alkoxy, -N(C) 1-6 Alkyl)2, C 3-10 Cycloalkyl, 3-10 membered heterocyclic alkyl, C 6-12 Aryl or 5-12 heteroaryl groups; preferably, R5 is selected from H, halogen, aldehyde, C. 1-4 Alkyl, Halogenated C 1-4 Alkyl, C 1-4 Alkoxy, halogenated C 1-4 Alkoxy, -N(C) 1-4 Alkyl)2, C 3-8 cycloalkyl, C 3-6 Cycloalkyl, 3-8 membered heterocycloalkyl, 3-6 membered heterocycloalkyl, C 6-10 Aryl, phenyl, or 5-10 heteroaryl, 5-6 heteroaryl; exemplary, R5 is selected from: H, aldehyde (-CHO), methoxy, halogen (e.g., F, Cl, Br, I), -N(Et)2 ( ), cyclopropyl (e.g.) ), tetrahydropyranyl (e.g.) ), phenyl.

[0015] According to an embodiment of the present invention, R6 is selected from H, halogens, and C. 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 1-6 Alkoxy, halogenated C 1-6 Alkyl group; preferably, R6 is selected from H, halogen, C 1-4 Alkyl, Halogenated C 1-4 Alkyl, C 1-4 Alkoxy, halogenated C 1-4 Alkyl group; for example, R6 is selected from: H, halogen.

[0016] According to an embodiment of the present invention, in formula (I), R a They are either the same or different, and are independently selected from H and C. 1-6 Alkyl, C 1-6 Alkoxy, CN, halogen; R1 is selected from: H, C 1-6 Alkyl group, -(CH2) 1-6 -S-CH3, -(CH2) 1-6 -CONH2、-(CH2) 1-6 -COOH, -CH2-C 6-10 Aryl or -CH2-5-10 heteroaryl; the -CH2-C 6-10 C in aryl and -CH2-5-10 heteroaryl groups 6-10The aryl and 5-10 heteroaryl groups are independently unsubstituted or optionally substituted by one, two or more R groups. b Replace; the C 1-6 Alkyl groups are unsubstituted or optionally substituted with one, two or more R groups. b Replace; R b Selected from H, hydroxyl, and halogen; R2 is selected from H, halogens, and C. 6-12 Aryl, C 1-6 alkyl; R3 is selected from H, halogens, CN, and C. 2-6 Alkenyl, 5-10 membered heteroaryl; R4 is selected from H, halogens, and 5-10 heteroaryl groups; R5 is selected from H, halogen, aldehyde, and C. 1-6 Alkyl, C 1-6 Alkoxy, -N(C) 1-6 Alkyl)2, C 3-8 Cycloalkyl, 3-8 membered heterocycloalkyl, C 6-10 Aryl; R6 is selected from H and halogens.

[0017] According to an embodiment of the present invention, in formula (I), R a They may be the same or different, and are independently selected from H, methyl, methoxy, CN, and halogens (e.g., F, Cl, Br, I). n is selected from 1 or 2; R1 is selected from: H, methyl, propyl (e.g., isopropyl). ), butyl (e.g., isobutyl) -CH2CH2-S-CH3 ( ), benzyl ( -CH(CH3)OH ), -CH2-phenyl-OH ( -CH2CH2-CONH2 ( -CH2CH2-COOH ), -CH2-imidazolium (e.g.) ), -CH2-indole (e.g.) ); R2 is selected from: H, methyl, phenyl; R3 is selected from: H, CN, vinyl ( ), pyrazolyl (e.g.) ); R4 is selected from: H, halogens (e.g., F, Cl, Br, I), pyridyl (e.g., ... ); R5 is selected from: H, aldehyde (-CHO), methoxy, halogen (e.g., F, Cl, Br, I), -N(Et)2 ( ), cyclopropyl (e.g.) ), tetrahydropyranyl (e.g.) ), phenyl; R6 is selected from: H, halogens (e.g., F, Cl, Br, I).

[0018] According to an embodiment of the present invention, the compound represented by formula (I) is selected from the compounds in Table 1 herein.

[0019] The present invention also provides a method for preparing the compound represented by formula (I) above, the method comprising the following steps: The compound shown in formula (Ia) is reacted with the compound shown in formula (Ib) and the compound shown in formula (Ic) to obtain the compound shown in formula (I); The reaction formula is as follows: ; Among them, R1, R2, R3, R4, R5, R6, R a , n has the definition as described above.

[0020] According to an embodiment of the present invention, the reaction is carried out in a solvent; the solvent is preferably water.

[0021] According to an embodiment of the present invention, after the reaction is completed, the reaction product may optionally be further separated and purified by means of extraction, column chromatography, or other methods. According to an embodiment of the present invention, extraction is, for example, ethyl acetate extraction.

[0022] The present invention also provides a pesticide composition comprising a compound of formula (I) above, its stereoisomers, racemates, tautomers, isotope labels, nitrogen oxides, agriculturally acceptable salts or esters, solvates, or solvates of agriculturally acceptable salts.

[0023] According to an embodiment of the invention, the pesticide composition is, for example, a fungicide.

[0024] According to embodiments of the present invention, the pesticide composition optionally further comprises an agriculturally acceptable carrier or excipient.

[0025] The present invention also provides the use of the compound represented by formula (I), its stereoisomers, racemates, tautomers, isotope labels, nitrogen oxides, agriculturally acceptable salts or esters, solvates or solvates of agriculturally acceptable salts, or the above-described pesticide compositions in the preparation of fungicides.

[0026] According to an embodiment of the present invention, the fungicide is used in the field of agronomy (agricultural fungicide) or horticulture (horticultural fungicide).

[0027] According to embodiments of the present invention, the fungicide can be used to control plant diseases caused by fungi and / or oomycetes. According to embodiments of the present invention, the fungicide can inhibit spore germination and appressorium formation of fungi and / or oomycetes.

[0028] According to an embodiment of the present invention, the fungicide prevents and controls plant diseases caused by fungi and / or oomycetes by inhibiting the germination of fungal and / or oomycete spores and the formation of appressoriums.

[0029] The present invention also provides the use of the compound represented by formula (I) above, its stereoisomers, racemates, tautomers, isotope markers, nitrogen oxides, agriculturally acceptable salts or esters, solvates or solvates of agriculturally acceptable salts, or the above pesticide compositions for the prevention and control of plant diseases caused by fungi and / or oomycetes.

[0030] According to an embodiment of the present invention, the fungus and / or oomycete is at least one of *Pyrophyte oryzae*, *Anthracis*, *Fusarium graminearum*, and *Phytophthora* (e.g., *Phytophthora pisicola*, *Phytophthora capsici*).

[0031] According to embodiments of the present invention, plants include crops such as potatoes, peppers, rice, wheat, mangoes, corn, soybeans, grapes, cucumbers, etc.

[0032] According to embodiments of the present invention, the plant diseases caused by the fungi and / or oomycetes are selected from the following: rice sheath blight, rice blast, rice false smut, sesame spot, and bakanae disease; wheat scab, stripe rust, stem rust, leaf rust, root rot, and sheath blight; maize large leaf spot, small leaf spot, anthracnose, stem base rot, rust, sheath blight, Curvularia leaf spot, common smut, and powdery mildew; mango anthracnose, potato late blight, soybean Phytophthora blight, pepper Phytophthora blight, grape downy mildew, and cucumber downy mildew.

[0033] According to embodiments of the present invention, the compound represented by formula (I), its stereoisomers, racemates, tautomers, isotope markers, nitrogen oxides, agriculturally acceptable salts or esters, solvates or solvates of agriculturally acceptable salts, or the above-described pesticide compositions, or the above-described fungicides, can inhibit the spore germination and appressorium formation of *Pyrrosia lingua*; for example, inhibiting the germination of conidia and the formation of appressorium of *Pyrrosia lingua*.

[0034] To achieve the desired effect, the amount of compound used varies depending on various factors, such as the compound used, the crop being protected, the type of pest, the degree of infection, climatic conditions, the application method, and the formulation used.

[0035] The selection of dosage forms or compositional components described herein should be consistent with the physical properties of the active ingredient, the method of application, and environmental factors such as soil type, humidity, and temperature.

[0036] The dosage forms of the compounds or compositions include liquids, such as solutions (including emulsifiable concentrates), suspensions, emulsions (including microemulsions and / or suspensions), etc., which may optionally be thickened into a gel. The dosage forms also include solid dosage forms, such as powders, granules, tablets, pills, films, etc., which may be water-dispersible (“wettable”) or water-soluble. The active ingredient may be microencapsulated and re-formed into a suspension or solid dosage form; alternatively, the entire dosage form of the active ingredient may be encapsulated. Encapsulation can control or delay the release of the active ingredient. Sprayable formulations can be diluted in a suitable medium, using a spray volume of approximately one hundred to several hundred liters per hectare. High-concentration compositions are primarily used as intermediates for further processing.

[0037] All formulations may contain small amounts of additives to reduce foaming, prevent clumping, prevent corrosion, and inhibit microbial growth, or thickeners to increase viscosity. Surfactants include, for example, polyethoxylated alcohols, polyethoxylated alkylphenols, polyethoxylated sorbitan fatty acid esters, sulfonated dialkyl succinates, alkyl sulfates, alkylbenzene sulfonates, organosilanes, N,N-dialkyl taurates, lignin sulfonates, naphthalene sulfonates with aldehyde condensates, polycarboxylate esters, and polyoxyethylene / polyoxypropylene block copolymers. Solid diluents include clays such as bentonite, montmorillonite, magnesia, and kaolin; starch; sugar; silica; talc; diatomaceous earth; urea; calcium carbonate; sodium carbonate; sodium bicarbonate; and sodium sulfate. Liquid diluents include water, N,N-dimethylformamide, dimethyl sulfone, N-alkylpyrrolidone, ethylene glycol, polypropylene glycol, paraffin wax, alkylbenzene, alkylnaphthalene, olive oil, castor oil, linseed oil, tung oil, sesame oil, corn oil, peanut oil, cottonseed oil, soybean oil, rapeseed oil, and cocoa butter; fatty acid esters; ketones such as cyclohexanone, 2-heptanone, isophorone, and 4-hydroxy-4-methyl-2-pentanone; and alcohols such as methanol, cyclohexanol, dodecyl alcohol, and tetrahydrofuranol. Solutions, including emulsifiable concentrates, can be prepared by simply mixing the components. Powders and fine powders can be prepared by mixing or, typically, by grinding in a hammer mill or hydraulic mill.

[0038] In this article, for certain applications of the composition, such as in agriculture, one, two or more other fungicides, insecticides, acaricides, herbicides, plant growth regulators or fertilizers may be added to the composition of the present invention, thereby producing additional advantages and effects.

[0039] Beneficial effects This invention provides a novel thiophene compound that significantly inhibits spore germination and appressorium formation of various plant pathogenic fungi and oomycetes (e.g., *Pseudomonas aeruginosa*, *Amycosis fungi*, *Fusarium graminearum*, *Phytophthora*, *Phytophthora capsici*). Furthermore, this invention demonstrates through indoor pot inoculation experiments that it can be used to control plant diseases caused by fungi and / or oomycetes.

[0040] Terminology Definitions and Explanations In partially substituents, " The "" indicates the connection point.

[0041] "More than" means three or more, such as 3, 4, 5 or 6.

[0042] In this document, the term "halogen" refers to fluorine, chlorine, bromine, and / or iodine. Correspondingly, the term "halogenated" refers to fluorination, chlorination, bromination, and / or iodination. Within the scope of this document, when an atom, residue, group, or part is halogenated, the atom at the halogenated position can be monosubstituted, disubstituted, or polysubstituted up to fully substituted by the halogen atom, for example, "halogenated C..." 1-12 Alkyl and Halogenated C 1-12 Alkoxy groups, etc.

[0043] Term "C" 1-10 "alkyl" should be understood to refer to a straight-chain or branched saturated monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably C14. 1-8 Alkyl or C 1-6 Alkyl or C 1-4 Alkyl group. "C" 1-6 "alkyl" should be understood to preferably represent a straight-chain or branched saturated monovalent hydrocarbon group having 1, 2, 3, 4, 5, or 6 carbon atoms. The alkyl group is, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, 2-methylbutyl, 1-methylbutyl, 1-ethylpropyl, 1,2-dimethylpropyl, neopentyl, 1,1-dimethylpropyl, 4-methylpentyl, 3-methylpentyl, 2-methylpentyl, 1-methylpentyl, 2-ethylbutyl, 1-ethylbutyl, 3,3-dimethylbutyl, 2,2-dimethylbutyl, 1,1-dimethylbutyl, 2,3-dimethylbutyl, 1,3-dimethylbutyl, or 1,2-dimethylbutyl, etc., or isomers thereof. In particular, the group has 1, 2, or 3 carbon atoms ("C..."). 1-3 Alkyl groups, such as methyl, ethyl, n-propyl, or isopropyl.

[0044] Term "C" 3-12 "Cycloalkyl" should be understood to refer to saturated monovalent monocyclic, bicyclic, or bridged cycloalkanes having 3 to 12 carbon atoms, preferably "C". 3-8 cycloalkyl. The term "C" 3-8"Cycloalkyl" should be understood to refer to saturated monovalent monocyclic, bicyclic, or bridged cycloalkanes having 3, 4, 5, 6, 7, or 8 carbon atoms. The C... 3-12 Cycloalkyl groups can be monocyclic hydrocarbon groups, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, or cyclodecyl, or bicyclic hydrocarbon groups such as decahydronaphthalene ring.

[0045] The term "3-12 membered heterocyclic alkyl" refers to a saturated or partially saturated monovalent monocyclic or bicyclic hydrocarbon ring containing 1-5, preferably 1-3, heteroatoms selected from N, O, and S. The heterocyclic alkyl group can be attached to the remainder of the molecule via any one of the carbon atoms or a nitrogen atom (if present). Specifically, the heterocyclic alkyl group can include, but is not limited to: 4-membered rings, such as azirrobutyl or oxobutyl; 5-membered rings, such as tetrahydrofuranyl, dioxacyclopentenyl, pyrrolyl, imidazoalkyl, pyrazolyl, or pyrrololinyl; or 6-membered rings, such as tetrahydropyranyl, piperidinyl, morpholinyl, dithiaalkyl, thiomorpholinyl, piperazinyl, or trithiaalkyl; or 7-membered rings, such as diazacycloheptyl. Optionally, the heterocyclic alkyl group can be benzofused. The heterocyclic alkyl group may be bicyclic, such as, but not limited to, a 5,5-membered ring, like a hexahydrocyclopentano[c]pyrrolo-2(1H)-yl ring, or a 5,6-membered bicyclic ring, like a hexahydropyrrolo[1,2-a]pyrazinolo-2(1H)-yl ring. The nitrogen-containing ring may be partially unsaturated, i.e., it may contain one or more double bonds, such as, but not limited to, 2,5-dihydro-1H-pyrroloyl, 4H-[1,3,4]thiadiazinyl, 4,5-dihydrooxazolyl, or 4H-[1,4]thiazinyl, or it may be benzofused, such as, but not limited to, dihydroisoquinolinyl.

[0046] The above refers to the term "C" 1-10 The definition of "alkyl" also applies to compounds containing "C". 1-10 Other terms for "alkyl", such as the term "halogenated C", 1-10 "alkyl" or "C" 1-10 "alkoxy" or "halogenated C" 1-10 "Alkyloxy" etc.

[0047] Term "C" 6-15 "Aryl" should be understood as referring to a monocyclic or bicyclic hydrocarbon ring with 6 to 15 carbon atoms, exhibiting monovalent aromaticity or partial aromaticity. The term "C"... 6-15 "Aryl" should be understood to preferably represent a monovalent aromatic or partially aromatic monocyclic or bicyclic hydrocarbon ring having 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 carbon atoms, particularly a ring with 6 carbon atoms ("C6 aryl"), such as phenyl; or a ring with 10 carbon atoms ("C6 aryl"). 10 Aryl groups, such as tetrahydronaphthyl, dihydronaphthyl, or naphthyl.

[0048] The term "5-15-membered heteroaryl" should be understood to include monovalent monocyclic and bicyclic aromatic ring systems having 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 ring atoms, particularly 5, 6, 9, or 10 carbon atoms, and containing 1-5, preferably 1-3, heteroatoms independently selected from N, O, and S, and in each case may be benzofused. Examples include pyridinyl, pyridazinyl, pyrazinyl, pyrimidinyl, indoleyl, pyrazolyl, etc.

[0049] "Stereoisomers" are compounds that have the same chemical structure but whose atoms or groups are arranged differently in space. Stereoisomers include enantiomers, diastereomers, conformational isomers (rotational isomers), geometric isomers (cis / trans) isomers, and hindered isomers, etc.

[0050] "Tautomers" refer 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 prototropic 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. A specific example of a keto-enol tautomer is the interconversion between pentane-2,4-dione and 4-hydroxypent-3-en-2-one. Another example of tautomerism is phenol-keto tautomerism. A specific example of a phenol-keto tautomer is the interconversion between pyridine-4-ol and pyridine-4(1H)-keto. Unless otherwise stated, all tautomer forms of the compounds of this invention are within the scope of this invention.

[0051] The term "nitrogen oxide" in this invention refers to an N-oxide formed by oxidizing one or more nitrogen atoms when the compound contains several amine functional groups. Specific examples of N-oxides are N-oxides of tertiary amines or N-oxides of nitrogen-containing heterocyclic nitrogen atoms. The corresponding amines can be treated with oxidizing agents such as hydrogen peroxide or peracids (e.g., peroxycarboxylic acids) to form N-oxides (see Advanced Organic Chemistry, Wiley Interscience, 4th edition, Jerry March, pages). In particular, N-oxides can be prepared using the LWDeady method (Syn.Comm. 1977, 7, 509-514), wherein the amine compound is reacted with m-chloroperoxybenzoic acid (MCPBA), for example in an inert solvent such as dichloromethane.

[0052] As used in this invention, the term "metabolite" refers to the product obtained in vivo through the metabolism of a specific compound or its salt. A metabolite of a compound can be identified using techniques known in the art, and its activity can be characterized by experimental methods as described in this invention. Such products can be obtained by administering the compound through oxidation, reduction, hydrolysis, acylation, deacylation, esterification, defatting, enzymatic cleavage, etc. Accordingly, this invention includes metabolites of compounds, including metabolites produced by sufficiently exposing the compounds of this invention to mammals for a period of time.

[0053] Agriculturally acceptable salts can be, for example, acid addition salts of compounds of the present invention having sufficient basicity and containing nitrogen atoms in the chain or ring, such as acid addition salts formed with inorganic acids including: hydrochloric acid, hydrofluoric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, pyrosulfuric acid, phosphoric acid or nitric acid, or bisulfate; or acid addition salts formed with organic acids including: formic acid, acetic acid, acetoacetic acid, pyruvic acid, trifluoroacetic acid, propionic acid, butyric acid, hexanoic acid, heptanoic acid, undecanoic acid, lauric acid, benzoic acid, salicylic acid, 2-(4-hydroxybenzoyl)benzoic acid, camphoric acid, cinnamic acid, cyclopentanepropionic acid, and diglucose. Gluconic acid, 3-hydroxy-2-naphtholic acid, nicotinic acid, pyruvic acid, pectinic acid, persulfate, 3-phenylpropionic acid, picric acid, pentyl acid, 2-hydroxyethanesulfonic acid, itaconic acid, aminosulfonic acid, trifluoromethanesulfonic acid, dodecyl sulfuric acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, methanesulfonic acid, 2-naphthalenesulfonic acid, naphthalenedisulfonic acid, camphorsulfonic acid, citric acid, tartaric acid, stearic acid, lactic acid, oxalic acid, malonic acid, succinic acid, malic acid, adipic acid, alginic acid, maleic acid, fumaric acid, D-gluconic acid, mandelic acid, ascorbic acid, glucohepanoic acid, glycerophosphate, aspartic acid, sulfosalicylic acid, hemisulfonic acid or thiocyanate.

[0054] Additionally, another suitable agriculturally acceptable salt of the compounds of the present invention having sufficient acidity is an alkali metal salt (e.g., sodium or potassium salt), an alkaline earth metal salt (e.g., calcium or magnesium salt), an ammonium salt, or a salt formed with an organic base that provides a physiologically acceptable cation, such as a salt formed with sodium ions, potassium ions, etc. NN-methylglucosamine, dimethylglucosamine, ethylglucosamine, lysine, dicyclohexylamine, 1,6-hexanediamine, ethanolamine, glucosamine, meglumine, sarcosine, serine, trihydroxymethylaminomethane, aminopropylene glycol, 1-amino-2,3,4-butanetriol. As examples, pharmaceutically acceptable salts include salts formed by the -COOH group with sodium, potassium, calcium, magnesium, N-methylglucosamine, dimethylglucosamine, ethylglucosamine, lysine, dicyclohexylamine, 1,6-hexanediamine, ethanolamine, glucosamine, meglumine, sarcosine, serine, trihydroxymethylaminomethane, aminopropylene glycol, 1-amino-2,3,4-butanetriol.

[0055] In addition, the basic nitrogen-containing group can be quaternized with the following reagents: lower alkyl halides, such as methyl, ethyl, propyl, and butyl chlorides, bromides, and iodides; dialkyl sulfates, such as dimethyl sulfate, diethyl sulfate, dibutyl sulfate, and dipentyl sulfate; long-chain halides, such as decyl, lauryl, myristyl, and stearyl chlorides, bromides, and iodides; aralkyl halides such as benzyl and phenethyl bromides, etc. As examples, pharmaceutically acceptable salts include hydrochlorides, sulfates, nitrates, hydrogen sulfates, hydrobromic acid salts, acetates, oxalates, citrates, methanesulfonates, formates, or meglumine salts, etc. Since the compounds of the present invention can have multiple salting sites, the pharmaceutically acceptable salts include not only salts formed at one salting site of the compounds of the present invention, but also salts formed at two, three, or all of the salting sites. Therefore, the molar ratio of the pharmaceutically acceptable salt of formula (I) compound to the anion of the acid or the cation of the base required for salt formation can vary over a wide range, for example, it can be 4:1 to 1:4, such as 3:1, 2:1, 1:1, 1:2, 1:3, etc.

[0056] In the conventional sense, the term "solvate" in this invention refers to a complex formed by a combination of a solute (such as an active compound or a salt of an active compound) and a solvent (such as water). The solvent refers to a solvent known or readily identifiable to those skilled in the art. If it is water, the solvate is generally referred to as a hydrate, such as a hemihydrate, monohydrate, dihydrate, trihydrate, or a substitute thereof. Detailed Implementation

[0057] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0058] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0059] Example 1: Preparation of the compound 1. Synthesis of compound A-038 first step:

[0060] 1.0 g of compound A38-1 was placed in a 50 mL round-bottom flask, and 10.0 mL of water was added. 94.0 mg of A38-2 and 54.0 mg of A38-3 were added with stirring, and the reaction was carried out at the response temperature. After the reaction was complete as detected by TLC, the mixture was diluted with water, extracted and concentrated with ethyl acetate, and purified by column chromatography to obtain compound A-038 as a yellow solid (330.2 mg). Characterization data of compound A-038: 1 ¹H NMR (500 MHz, deuterated dimethyl sulfoxide) δ 8.72 (s, ¹H), 8.08 – 8.00 (m, ¹H), 7.90 (dd, J = 34.5, 1.8 Hz, 1H), 7.66 – 7.62 (m, 1H), 7.51 (dd, J = 11.0, 1.8 Hz, 1H), 7.25 (td, J = 6.2, 2.7 Hz, 3H), 7.21 – 7.16 (m, 1H), 7.08 – 7.05 (m, 1H), 6.43(dt, J = 9.1, 2.4 Hz, 1H), 6.17 (dd, J = 6.3, 2.4 Hz, 1H), 4.77 (dd, J = 9.9, 5.2Hz, 2H), 3.43 (s, 4H), 2.08 (s, 1H), 1.11 (td, J = 6.1, 2.6 Hz, 6H).

[0061] Referring to the preparation method for the synthesis of compound A-038 mentioned above, the compounds shown in Table 1 below were prepared by replacing the raw materials.

[0062] Table 1 Structural formulas of compounds of formula (I)

[0063]

[0064]

[0065]

[0066] Table 2 shows the mass spectrometry data and / or data for the compounds listed in Table 1. 1 H-NMR data. Unless otherwise specified, deuterated dimethyl sulfoxide (DMSO) will be used. -d 6. Used as a test solvent.

[0067] In Table 2 and throughout the description below, “NMR” refers to nuclear magnetic resonance spectroscopy, and MS represents mass spectrometry. The following abbreviations are used: s = singlet, br = broad peak, d = doublet, dd = doubletuplet, t = triplet, td = tripletuplet, q = quartet, m = multiplet.

[0068] Table 2. Compound structure characterization data

[0069]

[0070]

[0071]

[0072] Note: “—” in Table 2 indicates that NMR data for this compound were not tested.

[0073] Example 2 Biological Experiment Given that *Pyrrosia lingua* infects plants via appressorium-mediated infection and can be cultured artificially indoors, *Pyrrosia lingua* can be used as a model pathogen to test the inhibitory effects of the compounds of this invention on conidium germination and appressorium formation. The relevant activities of the compounds of this invention are illustrated by the following examples.

[0074] Biological Experiment 1: Inhibitory Effect of Thiophene Compounds on Conidial Germination and Appressorium Formation of *Pyrrosia lingua* 1. Experimental material: P131 strain of *Pyrrosia lingua*.

[0075] 2. Experimental Method: The *Pyrrosia lingua* strain P131 was inoculated onto tomato-oat agar plates (OTA) and incubated at 28°C. After 3-5 days, the *Pyrrosia lingua* colonies on the OTA were completely broken up and then evenly spread onto new OTA plates, incubated at 28°C. When new mycelia appeared (generally 1-2 days), the mycelia were broken up with cotton swabs, rinsed with sterile water, and dried. The petri dishes were covered with a single layer of gauze and incubated at 28°C for 48 h, producing a large number of conidia on the OTA surface. The culture on the OTA was washed off with sterile water, filtered through three layers of lens paper, and the filtrate was the conidia solution. The conidia concentration was adjusted to 2 × 10⁻⁶. 5Add the sample solution of the target compound to the sample at a concentration of 6.25 ppm or 1.56 ppm to prepare working solutions. Spot the solutions sequentially onto hydrophobic glass slides. Place 9 spots on each slide and allow to dry in the dark. Observe and count the samples under a microscope after 12 hours.

[0076] 3. Statistical Analysis: Three inoculation sites were counted on each hydrophobic slide. At each inoculation site, the number of germinating conidia and the number of appressorium formations from 100 conidia at its center were counted. The average of the three sets of data was calculated to determine the conidia germination rate and appressorium formation rate. Parallel experiments using solvent were used as controls to calculate the inhibitory effect of the test compound on conidia germination and appressorium formation.

[0077] Table 3 shows the data from biological experiment 1 of the compounds of the present invention, where “+” represents an inhibition rate of less than or equal to 50% at a concentration of 6.25 ppm, “++” represents an inhibition rate of more than 50% at a concentration of 6.25 ppm, “+++” represents an inhibition rate of less than or equal to 50% at a concentration of 1.56 ppm, and “++++” represents an inhibition rate of more than 50% at a concentration of 1.56 ppm.

[0078] Experimental results show that the compounds of this invention have a good inhibitory effect on the germination of conidia and the formation of appressorium of *Pyrhodotorula oryzae*, and some compounds exhibit excellent inhibitory activity.

[0079] Table 3. Inhibitory effects of the compounds of this invention on conidial germination and appressorium formation of *Pyrrosia lingua*.

[0080] Biological Experiment 2: The Control Effect of Thiophene Compounds on Potted Rice Infected by Pyrethrum oryzae 1. Experimental materials: Pyridae bacillus strain 16-117, rice varieties CO39 and Xiangwanxian 11.

[0081] 2. Experimental Methods: Sporulation and spore preparation were the same as in Biological Experiment 1. The conidial concentration was adjusted to 5 × 10⁻⁶. 4 Add the test compound stock solution to the solution at a concentration of 100 ppm to prepare a 100 ppm working solution. Spray 15 mL of the working solution onto susceptible rice varieties Xiangwanxian 11 and CO39, spraying 10 seedlings of each treatment that are 2-3 weeks old. Incubate in the dark under moist conditions for 48 h, then proceed with normal culture. Seven days after inoculation, evaluate the control efficacy of the test compound against rice blast.

[0082] 3. Statistics and Analysis: Table 4 shows the data of biological experiment 2 of the compounds of the present invention (average values ​​of each treatment).

[0083] Rice blast leaf blast disease surveys were conducted in accordance with the agricultural industry standard "Technical Regulations for Field Monitoring of Rice Blast Resistance" (NY / T3685-2020). The specific standards are as follows: Grade 0: No disease on the entire leaf; Grade 1: Small brown necrotic spots on the leaf; Grade 2: Larger brown necrotic spots (1 mm-2 mm in diameter) on the leaf, but no typical lesions; Grade 3: Typical rice blast lesions, lesion area <2%; Grade 4: Typical rice blast lesions, 2% ≤ lesion area <5%; Grade 5: Typical rice blast lesions, 5% ≤ lesion area <10%; Grade 6: Typical rice blast lesions, 10% ≤ lesion area <25%; Grade 7: Typical rice blast lesions, 25% ≤ lesion area <50%; Grade 8: Typical rice blast lesions, 50% ≤ lesion area <75%; Grade 9: Typical rice blast lesions, lesion area ≥75%.

[0084] Experimental results show that the compounds of this invention have good control effects on potted rice infected with *Pyrhodotorula oryzae*, and some compounds show excellent control effects.

[0085] Table 4. Control effects of the compounds of this invention on potted rice infected with *Pyrethrum oryzae*.

[0086] Biological Experiment 3: The Control Effect of Thiophene Compounds on Anthracnose Infection of Exvial Mango Leaves 1. Experimental materials: Mango anthracnose strain SC2-1 and newly green 'Guifei' mango tender leaves were placed in an inoculation box for later use.

[0087] 2. Experimental Method: The anthrax strain SC2-1 was inoculated onto tomato-oat agar plates (OTA) and incubated at 25°C under constant temperature and light. After 5-7 days, the mycelia on the OTA were gently broken with a cotton swab, rinsed with sterile water, and air-dried. The petri dish was covered with a single layer of gauze and incubated at 25°C under light for 3-5 days, resulting in the production of a large number of spores on the OTA surface. The culture on the OTA was washed off with sterile water, filtered through three layers of lens paper, and the filtrate was the spore solution. The spore concentration was adjusted to 1×10⁻⁶. 6 Add the test compound stock solution to the solution at concentrations of 100 ppm, 100 ppm, or 50 ppm to prepare working solutions. Spot 10 µL of the working solution onto the surface of mango leaves, treat in the dark for 24 h, and then incubate normally. Evaluate the control effect of the test compound 7 days after inoculation.

[0088] 3. Statistics and Analysis: Five leaves were counted for each treatment, and one inoculation point was counted for each leaf. The lesion area at each inoculation point was recorded, and the average value was calculated to obtain the lesion area. The lesion area obtained from parallel experiments using solvent was used as a control to calculate the inhibitory effect of the test compound on anthracnose-infected mango leaves.

[0089] Table 5 shows the data from biological experiment 3 of the compounds of the present invention. "+" indicates an inhibition effect of less than or equal to 50% at 200 ppm, "++" indicates an inhibition effect of more than 50% at 200 ppm, "+++" indicates an inhibition effect of more than 50% at 100 ppm, and "++++" indicates an inhibition effect of more than 50% at 50 ppm.

[0090] Experimental results show that the compounds of this invention have good control effects against anthracnose infection of detached mango leaves, and some compounds show excellent control effects.

[0091] Table 5. The preventive and therapeutic effects of the compounds of this invention on anthracnose-infected detached mango leaves.

[0092] Biological Experiment 4: The Control Effect of Thiophene Compounds on Fusarium Head Blight Infection in Potted Wheat 1. Experimental materials: Fusarium graminearum strain Fg0609 and "Fielder" wheat cultured to the pre-ear and grain flowering stage.

[0093] 2. Experimental Method: The *Gibberellic acid* mycelial cake grown on PDA medium for 5 days was placed in CMC liquid medium and incubated at 28℃ and 180 rpm for 7 days. The mixture was filtered through three layers of lens paper, and the filtrate was used as the spore solution. The spore concentration was adjusted to 1×10⁻⁶. 5 Add the test compound stock solution to prepare a 100 ppm working solution. Using a pipette, inject 10 µL of the working solution into wheat ears before flowering, 5 ears per treatment. After 2 days of moistening, culture normally. Evaluate the control efficacy of the test compound 14 days after inoculation.

[0094] 3. Statistics and Analysis: Table 6 shows the data of biological experiment 4 of the compounds of the present invention (average values ​​of each treatment).

[0095] The wheat scab disease survey was conducted in accordance with the agricultural industry standard "Technical Regulations for Identification of Resistance to Fusarium Head Blight in Regional Wheat Trials" (NY / T2954-2016). The specific standards are as follows: Grade 0: No visible disease symptoms on inoculated spikelets; Grade 1: Disease only on inoculated spikelets; or disease on individual adjacent spikelets, but the lesions do not extend to the rachis; Grade 2: Disease on the rachis, with diseased spikelets accounting for less than 1 / 4 of the total spikelets; Grade 3: Disease on the rachis, with diseased spikelets accounting for 1 / 4 to 1 / 2 of the total spikelets; Grade 4: Disease on the rachis, with diseased spikelets accounting for more than 1 / 2 of the total spikelets.

[0096] Experimental results show that the compounds of this invention have good control effects against Fusarium wilt infection in potted wheat, and some compounds show excellent control effects.

[0097] Table 6. Control effects of the compounds of this invention on potted wheat infected with Fusarium graminearum.

[0098] Biological Experiment 5: The Control Effect of Thiophene Compounds on Potted Peppers Infected by Phytophthora capsici 1. Experimental materials: The *Phytophthora capsici* strain BYA5 and *Horn Pepper* seedlings were cultured normally for 2 weeks and then placed in an inoculation box for later use.

[0099] 2. Experimental Method: The strain was cultured on PDA medium for 10 days, then soaked in a small amount of sterile water and placed at 4°C in the dark for 3 hours before storage. o The prepared sporangia solution, adjusted with sterile water (C), was prepared to a concentration of 1×10⁻⁶. 5 A suspension of spores / mL was prepared. The stock solution of the test compound was diluted with water to a working concentration of 200 ppm. Five plants were treated per treatment, and each plant was sprayed with 20 mL of the working solution of the compound. After air drying, the plants were inoculated by drenching the roots with 10 mL of the prepared spore suspension. After 24 h of dark treatment, the plants were cultured under normal light (20℃, 18 h light / 6 h dark), and the disease development was observed at any time. The control effect of the test compound on pepper blight was evaluated after 5-7 days.

[0100] 3. Statistics and Analysis: Table 7 shows the data of biological experiment 5 of the compounds of the present invention (average values ​​of each treatment).

[0101] The investigation of pepper blight disease was conducted in accordance with the agricultural industry standard "Technical Specification for Identification of Pepper Disease Resistance Part 1: Technical Specification for Identification of Pepper Blight Disease" (NY / T2060.1-2011). The specific standards are as follows: Grade 0: No symptoms; Grade 1: Slight blackening of the seedling root and stem, leaves do not wilt or wilt reversibly; Grade 2: Blackening of the seedling root and stem up to 1-2 cm, irreversible wilting of leaves, and occasional shedding of lower leaves; Grade 3: Blackening of the seedling root and stem exceeding 2 cm, obvious wilting of leaves or obvious leaf drop; Grade 4: Blackening and constriction of the seedling root and stem, all leaves except the growing point fall off or the plant wilts; Grade 5: Plant dies.

[0102] Experimental results show that the compounds of this invention have good control effects on potted pepper plants infected with Phytophthora capsici, and some compounds show excellent control effects.

[0103] Table 7. Control effects of the compounds of this invention on potted pepper plants infected with Phytophthora capsici.

[0104] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A compound of formula (I) or an agriculturally acceptable salt thereof: ； Formula (I) in, R a Whether the two are the same or different, they are selected independently from H and C. 1-4 Alkyl, C 1-4 Alkoxy, CN, halogen; n is selected from 1 or 2; R1 is selected from: H, C 1-4 Alkyl, -CH2CH2-S-CH3, -CH(CH3)OH, -CH2CH2-CONH2, -CH2CH2-COOH, benzyl, -CH2-phenyl-OH, -CH2-imidazolyl, -CH2-indoleyl; R2 is selected from H and C. 1-4 Alkyl, phenyl; R3 is selected from H, CN, and C. 2-4 alkenyl, pyrazolyl; R4 is selected from H, halogen, or pyridyl; R5 is selected from H, halogen, aldehyde, and C. 1-4 Alkyl, C 1-4 Alkoxy, -N(C) 1-4 alkyl group, cyclopropyl group, tetrahydropyranyl group, phenyl group; R6 is selected from H and halogens.

2. The compound according to claim 1 or its agriculturally acceptable salt, characterized in that, In equation (I), R a They may be the same or different, and are independently selected from H, methyl, methoxy, CN, and halogen; And / or, R1 is selected from: H, methyl, propyl, butyl, -CH2CH2-S-CH3, benzyl, -CH(CH3)OH, -CH2-phenyl-OH, -CH2CH2-CONH2, -CH2CH2-COOH, - , ; And / or, R2 is selected from: H, methyl, phenyl; And / or, R3 is selected from: H, CN, vinyl, ; And / or, R4 is selected from: H, halogen, ; And / or, R5 is selected from: H, aldehyde, methoxy, halogen, -N(Et)2, cyclopropyl, , phenyl; And / or, R6 is selected from: H, halogen.

3. The compound according to claim 1 or its agriculturally acceptable salt, characterized in that, The compound represented by formula (I) is selected from the following compounds: ； ； ； 。 4. A method for preparing the compound of formula (I) according to claim 1 or an agriculturally acceptable salt thereof, comprising the following steps: The compound shown in formula (Ia) is reacted with the compound shown in formula (Ib) and the compound shown in formula (Ic) to obtain the compound shown in formula (I); The reaction formula is as follows: ； in, R1, R2, R3, R4, R5, R6, R a n has the definition in claim 1.

5. A pesticide composition comprising a compound of formula (I) as described in any one of claims 1-3 or an agriculturally acceptable salt thereof.

6. The use of the compound of formula (I) according to any one of claims 1-3 or an agriculturally acceptable salt thereof, or the pesticide composition according to claim 5, in the preparation of a fungicide.

7. The application according to claim 6, characterized in that, The fungicide is used to prevent and control plant diseases caused by fungi and / or oomycetes.

8. The application according to claim 6, characterized in that, The bactericide is used to inhibit spore germination and appressorium formation of fungi and / or oomycetes.

9. The application according to claim 7 or 8, characterized in that, The fungi and / or oomycetes are at least one of Pyridae, Anthrax, Fusarium head blight, and Phytophthora.

10. The application according to claim 7, characterized in that, The plant diseases caused by the fungi and / or oomycetes are selected from the following: rice blast, wheat scab, mango anthracnose, and pepper blight.

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