Bactericides containing a pyrazine structure, and methods of making and using the same

Abstract

The present invention relates to fungicides containing a pyrazine structure, and methods of making and using the same. Specifically, the present invention provides a compound of Formula (I), wherein each substituent or group is as described in the specification or claims. The compounds of the present invention have significant fungicidal activity against eight plant pathogenic fungi, and some of the compounds have better fungicidal effects than tetraconazole and azoxystrobin.

Description

Technical Field

[0001] This invention belongs to the field of pesticides, specifically, it relates to fungicides containing pyrazine structures, their preparation methods, and uses. Background Technology

[0002] Fungal diseases are a major factor restricting global agricultural production and causing crop yield reduction and quality decline. Chemical control, as the most economical and effective means of controlling plant fungal diseases, plays an irreplaceable role in modern agriculture. However, with the long-term and singular use of fungicides, the problem of pathogen resistance has become increasingly prominent, and the potential risks of traditional pesticides to the environment and non-target organisms have also attracted widespread attention. Therefore, the development of novel fungicides with novel skeletons, high activity, and low toxicity has always been a research hotspot in the field of pesticide creation.

[0003] Strobilurins, a class of biomimetic pesticides derived from natural products, act as mitochondrial respiration inhibitors (QoIs) by blocking cytochrome P450. b.c. 1 (Cty) b.c. 1 Methoxyacrylates disrupt the energy cycle of fungi by utilizing electron transfer in their complexes. Representative fungicides such as azoxystrobin and pyraclostrobin are widely used for disease control in various crops. However, due to their single site of action, many plant pathogens have developed varying degrees of resistance over time, limiting their further application. Therefore, structural modification or skeleton replacement of the pharmacophores in methoxyacrylate molecules is a crucial strategy for overcoming resistance and developing next-generation ultra-efficient fungicides.

[0004] Nitrogen-containing heterocyclic compounds play a crucial role in pharmaceutical and pesticide molecular design. Among them, pyrazine structures, as important electron-deficient aromatic heterocycles, are widely found in many bioactive natural products and synthetic drugs. Studies have shown that introducing pyrazine structures often significantly improves the lipophilicity of molecules and enhances their binding ability to receptor proteins, thereby endowing compounds with excellent fungicidal, insecticidal, or herbicidal activities. For example, some compounds containing pyrazine skeletons have shown good inhibitory effects against various pathogens such as rice sheath blight and wheat scab. On the other hand, oxime ether structures possess good chemical stability and unique biological activity, making them classic linking groups in pesticide molecular design. Many commercially available methoxyacrylate fungicides (such as azoxystrobin and tebuconazole) contain oxime ether structures. This structure can not only regulate the spatial conformation of the molecule but also enhance the affinity between the molecule and the target site through hydrogen bonding and other mechanisms.

[0005] Therefore, there is an urgent need in the field to develop a class of methoxyacrylate derivatives containing pyrazine structures to improve antifungal activity against common fabric pathogens and overcome the shortcomings of existing technologies. Summary of the Invention

[0006] The main objective of this invention is to provide a series of novel methoxyacrylate derivatives containing pyrazine structures, which exhibit significant in vitro antibacterial activity against common plant pathogenic fungi such as rice sheath blight and rapeseed sclerotinia.

[0007] In a first aspect, the present invention provides a compound of formula I, or a pesticide-acceptable salt thereof. I in, S1 is selected from the following group: , , ; R1 is H or each of the following substituents independently is 1-3 selected from the group consisting of halogen, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 haloalkyl, and C1-C6 haloalkoxy; R2 is each of 0-3 substituents selected from the following group: -NH2, -NO2, -CN, halogen, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 haloalkyl, C1-C6 haloalkoxy, C3-C8 cycloalkyl, and C3-C8 heterocyclic alkyl containing 1-3 N, O or S atoms.

[0008] In another preferred embodiment, R2 is each independently one to three substituents selected from the group consisting of: -NH2, -NO2, -CN, halogen, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 haloalkyl, C1-C6 haloalkoxy, C3-C8 cycloalkyl, and C3-C8 heterocyclic alkyl containing one to three N, O, or S atoms.

[0009] In another preferred embodiment, R2 is each independently one or two substituents selected from the group consisting of halogen, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 haloalkyl, and C1-C6 haloalkoxy.

[0010] In another preferred embodiment, R2 is each independently one or two substituents selected from the group consisting of halogen, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 haloalkyl, and C1-C6 haloalkoxy.

[0011] In another preferred embodiment, R2 is a halogen or a C1-C3 alkyl group.

[0012] In another preferred embodiment, the compound is selected from the group consisting of: .

[0013] A second aspect of the present invention provides a method for preparing a compound as described in the first aspect of the present invention, comprising the following steps: When the compounds of formula I are III-5 to III-33, the synthesis is as follows: In an inert solvent, compound III-4a is coupled with compound III-1 to prepare III-5 to III-33. When the compound of formula I is III-34 to III-40, the synthesis is as follows: In an inert solvent, compound III-4a is coupled with compound III-2 to prepare III-34~III-40. When the compounds of formula I are III-41 to III-46, the synthesis is as follows: In an inert solvent, compound III-4a is coupled with compound III-3 to prepare III-41 to III-46. R1 and R2 are as defined in the first aspect of this invention.

[0014] A third aspect of the present invention provides a composition comprising: (i) the compound as described in the first aspect of the invention or a pharmaceutically acceptable salt thereof; and (ii) Pharmaceutically acceptable carriers.

[0015] A fourth aspect of the invention provides a use of the compound as described in the first aspect of the invention, the use comprising: (a) Used in the preparation of bactericides; (b) Used as a bactericide.

[0016] A fifth aspect of the present invention provides a method for sterilization, the method comprising contacting a crop with a fungal disease with an effective amount of a compound as described in the first aspect of the present invention or a composition as described in the third aspect of the present invention.

[0017] It should be understood that, within the scope of this invention, the above-described technical features of this invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here. Detailed Implementation

[0018] Through extensive and in-depth research, based on the drug design principle of substructure splicing, this invention retains the toxophore of methoxyacrylate fungicides and links it to a potentially biologically active pyrazine skeleton via an oxime ether bond, designing and synthesizing a series of novel methoxyacrylate derivatives containing pyrazine structures. The target compounds were tested for in vitro antifungal activity against common plant pathogenic fungi such as *Rhizoctonia solani* and *Sclerotinia sclerotiorum*, providing a theoretical basis and material foundation for the creation of novel fungicides with independent intellectual property rights. Based on this, this invention was completed.

[0019] the term In this invention, unless otherwise specified, the terms used have the general meanings known to those skilled in the art.

[0020] In this invention, the term "halogen" refers to F, Cl, Br, or I.

[0021] In this invention, "C1-C6 alkyl" refers to a straight-chain or branched alkyl group comprising 1-6 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, neopentyl, pteropentyl, or similar groups. The similar term "C1-C4 alkyl" has a similar definition.

[0022] In this invention, the term "C1-C6 alkoxy" refers to a straight-chain or branched alkoxy group having 1 to 6 carbon atoms, including but not limited to methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, tert-butoxy, etc. Similar terms such as "C1-C4 alkoxy" have similar definitions.

[0023] In this invention, the term "C3-C8 cycloalkyl" represents a cyclic aliphatic hydrocarbon group consisting of 3 to 8 cyclic carbon atoms, and so on. It should be understood that "cycloalkyl" as used in this invention includes not only monocyclic aliphatic hydrocarbon groups, but also fused ring, spiro ring, and bridged ring systems composed of multiple cyclic aliphatic hydrocarbons. "Cycloalkyl" as used in this invention includes not only aliphatic hydrocarbon groups with fully saturated carbon atoms, but also aliphatic hydrocarbon groups with some carbon atoms having unsaturated bonds. Examples of "cycloalkyl" as used in this invention include, but are not limited to: , , , , , , , When "cycloalkyl" is used as a substituent, the connection site with the main molecule can occur at any position allowed by the chemical bonds on the "cycloalkyl". Terms such as "C3-C6 cycloalkyl" have similar definitions.

[0024] In this invention, the term "heterocyclic alkyl" refers to a non-aromatic cyclic group that indicates a specific number of cyclic atoms, contains at least one cyclic heteroatom (N, O, or S), and is saturated or partially unsaturated. It should be understood that the "heterocyclic group" described in this invention includes not only monocyclic heterocyclic systems but also polycyclic heterocyclic systems, such as fused rings, spirocyclic rings, and bridged rings. When the "heterocyclic group" is a polycyclic system, at least one ring contains a cyclic heteroatom, and the other rings may contain cyclic heteroatoms or be cyclic alkyl groups. For example, the term "4-8 membered heterocyclic alkyl" refers to a monocyclic or polycyclic system having 4 to 8 cyclic atoms, at least one of which is a heteroatom, and is saturated or partially unsaturated. The definitions of other similar terms follow the same pattern. More preferably, the number of heteroatoms is 1 to 3. This includes (but is not limited to) the following groups: , , , , , , , , , , , It is important to understand that when a "heterocyclic group" is used as a substituent, the connection site with the main body of the molecule can occur at any position allowed by the chemical bonds on the "heterocyclic group".

[0025] In this invention, the term "halogenated" refers to being replaced by a halogen.

[0026] In this invention, the term "optionally" means that when there is a series of candidate groups to choose from, some of them can be selected, or none can be selected.

[0027] In this invention, "each independently" means that when several substituents defined at the same time are selected from the same series of candidate groups, they do not affect each other, and they may be the same or different.

[0028] In this invention, the term "substitution" refers to the replacement of one or more hydrogen atoms on a specific group by a specific substituent. The specific substituent is either the substituent described accordingly above or the substituent appearing in the various embodiments. Unless otherwise specified, a substituted group may have a substituent selected from a specific group at any substituted site of that group, and the substituents at each position may be the same or different. Those skilled in the art will understand that the combinations of substituents contemplated in this invention are those that are stable or chemically feasible.

[0029] In this invention, the term "1-6" refers to having 1, 2, 3, 4, 5 or 6, and other similar terms each have a similar meaning independently.

[0030] It should be understood that when a group exists simultaneously at multiple different positions in a compound, its definition at each position is independent and can be the same or different. That is, the term "selected from the following group:" and the term "each independently selected from the following group:" have the same meaning.

[0031] The compound represented by Formula I of this invention and its preparation method This invention provides a compound of formula I, or a pharmaceutically acceptable salt thereof. I in, S1 is selected from the following group: , , ; R1 is H or each of the following substituents independently is 1-3 selected from the group consisting of halogen, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 haloalkyl, and C1-C6 haloalkoxy; R2 is each of 0-3 substituents selected from the following group: -NH2, -NO2, -CN, halogen, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 haloalkyl, C1-C6 haloalkoxy, C3-C8 cycloalkyl, and C3-C8 heterocyclic alkyl containing 1-3 N, O or S atoms.

[0032] In another preferred embodiment, the number of R2 is 1-2, and R2 is a halogen or a C1-C3 alkyl group.

[0033] As used herein, the term "pesticide-acceptable salt" means that the anion of the salt is known and acceptable in forming an insecticide-pesticide-acceptable salt. Preferably, the salt is water-soluble. Suitable acid addition salts formed from compounds of formula (I) include salts formed from inorganic acids, such as hydrochlorides, phosphates, sulfates, and nitrates; and salts formed from organic acids, such as acetates, benzoates, etc.

[0034] The preparation methods of the compounds of Formula I of the present invention are described in more detail below, but these specific methods do not constitute any limitation on the present invention. The compounds of the present invention can also be conveniently prepared by optionally combining various synthetic methods described in this specification or known in the art, such combinations being readily performed by those skilled in the art.

[0035] Typically, the preparation process of the compounds of the present invention is as follows, wherein the raw materials and reagents used can be purchased commercially unless otherwise specified.

[0036] The general synthesis method is as follows: Combinations containing the compounds of the present invention and uses of the compounds and compositions thereof. The present invention provides compounds as shown in Formula I or agricultural compositions comprising compounds as shown in Formula I and their uses.

[0037] The compound represented by Formula I of this invention is also suitable for controlling at least one of the following plant diseases caused by infection with Rhizoctonia solani, Pseudomonas, Pseudomonas, Pseudomonas, Pseudomonas, Pythium, etc.: anthracnose, leaf spot, rust, powdery mildew, sheath blight, leaf blight, gray mold, white mold, damping-off, Fusarium head blight, take-all, and target spot. Examples of plants affected by the fungal diseases include soybean, corn, wheat, cucurbits, rice, strawberry, peanut, and cotton; examples of the fungal diseases include soybean rust, corn rust, wheat powdery mildew, cucurbit powdery mildew, rice sheath blight, wheat sheath blight, strawberry gray mold, peanut white mold, cotton damping-off, wheat Fusarium head blight, wheat take-all, and cucumber target spot, wherein the cucurbit powdery mildew includes cucumber powdery mildew, etc.; the pathogens include *Pseudomonas spp.* Phakopsora pachyrhizome syd .), Corn stalk rust fungus ( Powdery mildew sorghum Schw ), powdery mildew ( Flower shop grass ), Powdery mildew ( Erysipelas cucurbitaceae ), Powdery mildew ( Spheroid squash ), Cucurbita cylindrica ( Thanatephorus cucumber ), Rhizoctonia glutinum ( Rhizoctonia cerealis ), and Rhizoctonia solani ( Rhizoctonia solani ), Botrytis cinerea ( Botrytis gray Persian .), Grain Sickle Robe ( Fusarium grasses sw .), Oat Fusarium ( Fusarium oat grass ), Fusarium moniliforme ( Fusarium ring-shaped shield .), Monocellular rust fungi ( Uromyces Phytophthora () Phytophthora ), Pythium ( Pythium ).

[0038] The compounds of Formula I of this invention can be prepared into fungicide compositions using conventional methods. These active compounds can be formulated into conventional preparations, such as solutions, emulsions, suspensions, powders, foams, pastes, granules, aerosols, natural and synthetic materials impregnated with active substances, microcapsules in polymers, seed coating compounds, and preparations for use with combustion devices, such as fumigation cylinders, fumigation canisters and fumigation trays, as well as ULV cold mist and warm mist preparations.

[0039] These formulations can be produced using known methods, such as mixing the active compound with a expander, which can be a liquid, liquefied gas, or solid diluent or carrier, and can be any type of surfactant, i.e., emulsifier and / or dispersant and / or foaming agent. For example, when water is used as the expander, organic solvents can also be used as adjuvants.

[0040] Liquid solvents are generally suitable as diluents or carriers, such as: aromatic hydrocarbons, such as xylene, toluene, or alkylnaphthalene; chlorinated aromatic or chlorinated aliphatic hydrocarbons, such as chlorobenzene, vinyl chloride, or dichloromethane; aliphatic hydrocarbons, such as cyclohexane or paraffins, such as mineral oil fractions; alcohols, such as ethanol or ethylene glycol and their ethers and esters; ketones, such as acetone, methyl ethyl ketone, methyl isobutyl ketone, or cyclohexanone; or less commonly used polar solvents, such as dimethylformamide and dimethyl sulfoxide, and water.

[0041] A liquefied gas diluent or carrier refers to a liquid that will become a gas at normal temperature and pressure, such as aerosol propellants, halogenated hydrocarbons, and butane, propane, nitrogen, and carbon dioxide.

[0042] Solid carriers can be ground natural minerals such as kaolin, clay, talc, quartz, activated clay, montmorillonite, or diatomaceous earth; and ground synthetic minerals such as highly dispersed silica, alumina, and silicates. Solid carriers for granulation are crushed and graded natural zircon, such as calcite, marble, pumice, sepiolite, and dolomite, as well as granules synthesized from inorganic and organic coarse powders, and granules of organic materials such as sawdust, coconut husks, corncobs, and tobacco stalks.

[0043] Nonionic and anionic emulsifiers can be used as emulsifiers and / or foam forming agents. Examples include polyoxyethylene-fatty acid esters, polyoxyethylene-fatty alcohol ethers, such as alkylaryl polyethylene glycol ethers, alkyl sulfonates, alkyl sulfates, aryl sulfonates, and albumin hydrolysates. Dispersants include lignin sulfite waste and methylcellulose.

[0044] Binders, such as carboxymethyl cellulose, and natural and synthetic polymers in the form of powders, granules, or emulsions, such as gum arabic, polyvinyl alcohol, and polyvinyl acetate, can be used in the formulation.

[0045] Coloring agents such as inorganic dyes, like iron oxide, cobalt oxide, and Prussian blue; organic dyes, like azo dyes or metallic phthalocyanine dyes; and trace nutrients, such as salts of iron, manganese, boron, copper, cobalt, aluminum, and zinc, can be used.

[0046] The compounds of Formula I of this invention can be mixed with other active compounds and exist in their commercial formulations or in dosage forms prepared from these formulations. These other active compounds are insecticides, fungicides, herbicides, growth regulators, etc. Insecticides include, for example, phosphate esters, carbamates, chlorinated hydrocarbons, and substances produced by microorganisms, such as avermectin. Fungicides include methoxyacrylates, amides, triazoles, etc.

[0047] Furthermore, the compounds shown in Formula I of the present invention can also be mixed with synergists and exist in their commercial formulations or in dosage forms prepared from these formulations. These synergists are compounds that enhance the activity of the active compound. Since the active compound is active on its own, it is not necessary to add synergists.

[0048] These formulations typically contain 0.001-99.99% by weight, preferably 0.01-99.9% by weight, and more preferably 0.05-90% by weight of the active compound of the present invention, representing 0.001-99.9% by weight of the total weight of the bactericidal composition. The concentration of the active compound in commercial formulations or drug formulations can vary within a wide range. The concentration of the active compound in drug formulations can range from 0.0000001-100% (g / v), preferably between 0.0001 and 1% (g / v), and various variations and modifications can be made within the scope defined by the claims of the present invention.

[0049] Compared with the prior art, the advantages of the present invention are as follows: (a) The compound described in this invention is a novel bactericide with a simple and easy preparation route.

[0050] (b) The compounds of the present invention have significant inhibitory activity against apple rot fungus, rapeseed sclerotium rot fungus and tomato gray mold fungus.

[0051] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed according to the conditions described in the conventional conditions or according to the conditions recommended by the manufacturer. Unless otherwise stated, percentages and parts are weight percentages and parts by weight.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as are familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. The preferred embodiments and materials described herein are for illustrative purposes only.

[0053] intermediate preparation Synthesis of Compound III-1 At 0 °C, an aqueous solution of sodium bicarbonate (94.5 mmol, 7.9 g) was added dropwise to a DCM solution of compound ia-d (27 mmol), followed by the dropwise addition of a DCM solution of triphosgene (9.45 mmol) until no gas was produced, indicating that the reaction was complete. After the reaction was confirmed by TLC, the product was extracted with DCM (3 × 400 mL). The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and then distilled under reduced pressure to obtain the crude product. Separation by silica gel column chromatography (v / v: ethyl acetate / petroleum ether = 1 / 4) yielded compound iia-d.

[0054] Under ice bath conditions, compound iia-d (20 mmol) and trimethylsilane azide (60 mmol) were slowly added sequentially to a three-necked flask protected with N2. The reaction mixture was stirred in an oil bath at 100 °C for 6 h. After the reaction was complete as detected by TLC, the mixture was cooled to room temperature and extracted with ethyl acetate (3 × 300 mL). The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and distilled under reduced pressure to obtain the crude product. The crude product was then separated by silica gel column chromatography (v / v: ethyl acetate / petroleum ether = 1 / 4) to give product iiia-d.

[0055] Compound iiia-d (5 mmol) was dissolved in N,N-dimethylformamide (DMF, 100 mL), followed by the sequential addition of iodomethane (10 mmol) and cesium carbonate (10 mmol). The mixture was stirred at room temperature for 6–8 h. After the reaction was confirmed by TLC, saturated sodium chloride solution (200 mL) was added to the system, and the mixture was extracted with ethyl acetate (3 × 200 mL). The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and distilled under reduced pressure to obtain the crude product. The crude product, iva-d, was then separated by silica gel column chromatography (v / v: ethyl acetate / petroleum ether = 1 / 3).

[0056] Compound iva-d (3 mmol) was dissolved in carbon tetrachloride (100 mL), followed by the addition of NBS (3.3 mmol). The reaction system was heated in a 90°C oil bath, and then AIBN (0.3 mmol) and BPO (0.15 mmol) were added as initiators. The mixture was stirred for 6–8 hours. After the reaction was completed as detected by TLC, the mixture was cooled to room temperature, filtered, and the filtrate was washed successively with dichloromethane (DCM) and water to separate the organic phase. The organic phase was dried over anhydrous sodium sulfate, filtered, and then distilled under reduced pressure to obtain the crude product. The crude product was then separated by silica gel column chromatography (v / v: ethyl acetate / petroleum ether = 1 / 3) to obtain the target product III-1a–III-1d.

[0057] 4-methylquinoline- N -Oxide (5 mmol) was dissolved in THF (100 mL), followed by the addition of compound III-1d (1.25 mmol). The mixture was heated to 80 °C and refluxed, with stirring for 2 h. After the reaction was completed as detected by TLC, the mixture was cooled to room temperature and extracted with ethyl acetate (3 × 100 mL). The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and distilled under reduced pressure to give crude product v.

[0058] Under N2 protection, compound v (1 mmol), potassium carbonate (2 mmol), trimethylboroxy (2 mmol), Pd(dppf)cl2 (0.05 mmol), and 1,4-dioxane (100 mL) were added sequentially to a reaction flask. The mixture was heated to 100 °C and refluxed, and the reaction was stirred for 2 h. After the reaction was completed as detected by TLC, the mixture was cooled to room temperature, the pH was adjusted to 8, and the mixture was extracted with ethyl acetate (3 × 100 mL). The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and distilled under reduced pressure to obtain the crude product. The crude product vi was then separated by silica gel column chromatography (v / v: ethyl acetate / petroleum ether = 1 / 3) to obtain the target product vi.

[0059] Compound vi (1 mmol) was dissolved in methanol (50 mL), and sodium borohydride (2.0 mmol) was added in portions at 0 °C. The mixture was stirred at room temperature until the reactants were completely reacted. After the reaction was completed, saturated ammonium chloride solution was slowly added dropwise to quench the reaction. The mixture was extracted with ethyl acetate (3 × 100 mL), and the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and distilled under reduced pressure to obtain the target product vii.

[0060] Compound vii (0.5 mmol) was dissolved in dichloromethane (DCM, 10 mL), and PBr3 (0.5 mmol) was slowly added at 0 °C. After the addition was complete, the reaction was stirred at 0 °C for 30 min. After the reaction was confirmed by TLC, 10% sodium metabisulfite solution (1 mL) was added to quench the reaction, and the mixture was extracted with dichloromethane (3 × 100 mL). All organic phases were combined, dried over anhydrous sodium sulfate, filtered, and distilled under reduced pressure to obtain the crude product. The crude product was then separated by silica gel column chromatography (v / v: ethyl acetate / petroleum ether = 1 / 3) to obtain the target product III-1e.

[0061] Synthesis of Compound III-2 In a round-bottom flask, 10.0 g (0.067 mol) of o-tolueneacetic acid, 200 mL of water, and 0.1 mol of NaOH were added sequentially. Then, 5.0 g of KMnO4 was added in portions (adding more when the solution turned brown), for a total addition of 21.0 g (0.134 mol). After the addition was complete, the mixture was allowed to react at room temperature for 10 h. Saturated NaHSO3 aqueous solution was then added until the purple-red color disappeared. The mixture was filtered to remove solid impurities, and the pH of the solution was adjusted to 1 with 10% dilute hydrochloric acid. The solution was extracted with ethyl acetate, dried over anhydrous sodium sulfate, and distilled under reduced pressure to obtain a colorless liquid, which was the crude product of compound viiii.

[0062] Compound viiii (0.03 mol) was dissolved in 30 mL of methanol, and 2 mL of concentrated sulfuric acid was added dropwise as a catalyst. The mixture was heated under reflux for 2 h. After the reaction was completed as detected by TCL, the methanol was removed, and the product ix was obtained by column chromatography (v / v: ethyl acetate / petroleum ether = 1 / 10), which yielded a pale yellow oily product.

[0063] Compound ix (0.022 mol) was dissolved in 25 mL of methanol. After stirring at room temperature for 10 min, 3.7 g (0.044 mol) of methoxyamine hydrochloride was added. The mixture was refluxed at 80 °C for 2 h, followed by the addition of 1 mL of concentrated sulfuric acid, and the reaction was continued for 3 h. After the reaction was completed as detected by TCL, excess methanol was removed, 100 mL of water was added, and the mixture was extracted with ethyl acetate. The organic phase was dried over anhydrous sodium sulfate and then subjected to column chromatography (v / v: ethyl acetate / petroleum ether = 1 / 5) to give a white solid as x.

[0064] Compound x (0.01 mol) was dissolved in 20 mL of CCl4 and stirred at room temperature for 10 min. Then, 3.6 g (0.02 mol) of NBS and 0.24 g (0.001 mol) of BPO were added in portions as initiators, and the mixture was stirred at room temperature for 30 min. The mixture was then heated to 85 °C and refluxed for 3 h. After the reaction was completed as detected by TCL, the CCl4 was removed, 30 mL of water was added to the flask, and the mixture was extracted with ethyl acetate. The organic phase was dried over anhydrous sodium sulfate and then subjected to column chromatography (v / v: ethyl acetate / petroleum ether = 1 / 4) to obtain a colorless oily liquid, III-2.

[0065] Synthesis of Compound III-3 o-Nitrotoluene (5 mmol) and ammonium chloride (7 mmol) were dissolved in water, and then zinc powder (10 mmol) was slowly added. The reaction was carried out at 50–65 °C for half an hour. After the reaction was completed by TLC, the zinc powder was filtered off, and the product was extracted with ethyl acetate (3 × 400 mL). The organic phases were combined, dried over anhydrous sodium sulfate, and the solvent was removed by vacuum distillation to give compound xi.

[0066] Compound xi (4 mmol) and NaCO3 (6 mmol) were dissolved in dichloromethane, and then methyl chloroformate (4.8 mmol) was slowly added dropwise. The mixture was reacted at -10 °C for 3 h to obtain a solution of compound xii.

[0067] K2CO3 (6 mmol) was added to a solution of compound xii (4 mmol), followed by the slow addition of methyl sulfate (6 mmol). The mixture was refluxed for 24 h to obtain a solution of compound xiii.

[0068] NBS (3.6 mmol) and AIBN (0.3 mmol) were added to a solution (3 mmol) of compound xiii, and the mixture was refluxed for 8 h. After the reaction was completed as detected by TLC, the product was extracted with dichloromethane (3 × 400 mL). The organic phases were combined, dried over anhydrous sodium sulfate, and the solvent was removed by vacuum distillation to give compound III-3.

[0069] Compound preparation examples Example 1 III-5: Compound III-4a (0.5 mmol) and compound III-1 (0.6 mmol) were dissolved in 15 mL of acetonitrile, and then 0.05 mmol of potassium iodide and 1 mmol of cesium carbonate were added. The mixture was placed in an oil bath at 90 °C and reacted for 6-8 h. After the reaction was completed by TLC, the reaction solution was filtered and concentrated under reduced pressure. The crude product was purified by column chromatography (v / v: dichloromethane / =20 / 1) to obtain the target compound III-5.

[0070] Yield: 45.6%, yellow solid, mp: 126-128 ℃; 1 H NMR (400 MHz, CDCl3) δ8.56 – 8.52 (m, 1H), 8.52 – 8.49 (m, 1H), 8.48 (d, J = 2.5 Hz, 1H), 7.65 –7.59 (m, 1H), 7.57 – 7.42 (m, 3H), 5.38 (s, 2H), 3.70 (s, 3H), 2.24 (s, 3H);HRMS (ESI) calculated for C 15 H 16 N7O2 + [M+H] + , 326.1360; found, 326.1358. Following the preparation method of Example 1, the following compounds were synthesized: III-6: Yield: 32.6%, yellow solid, mp: 153-155 ℃; 1 H NMR (400 MHz, CDCl3) δ 8.45– 8.34 (m, 2H), 7.58 (d, 1H), 7.53 – 7.44 (m, 3H), 5.35 (s, 2H), 3.70 (s,3H), 2.49 – 2.46 (m, 3H), 2.21 (s, 3H); HRMS (ESI) calculated for C 16 H 18 N7O2 + [M+H] + , 340.1517; found, 340.1520. III-7: Yield: 41.8%, bright yellow liquid.1 H NMR (400 MHz, CDCl3) δ 8.38 – 8.27 (m,2H), 7.53 – 7.29 (m, 4H), 5.26 (s, 2H), 3.62 (s, 3H), 2.69 (d, J = 7.5 Hz,2H), 2.12 (s, 3H), 0.99 (t, J = 7.4 Hz, 3H). III-8: Yield: 56.0%, yellow solid, mp: 115-117 ℃; 1 H NMR (400 MHz, CDCl3) δ8.27 (d, J = 20.5 Hz, 1H), 7.58 (dd, J = 7.3, 1.9 Hz, 1H), 7.54 – 7.43 (m,3H), 5.34 (s, 2H), 3.70 (s, 3H), 2.53 (d, J = 13.5 Hz, 3H), 2.45 (d, J = 16.7Hz, 3H), 2.19 (s, 3H); 1 HRMS (ESI) calculated for C 17 H 20 N7O2 + [M+H] + , 354.1673;found, 354.1628. III-9: Yield: 32.0%, bright yellow liquid; 1 H NMR (400 MHz, CDCl3) δ 7.59 (d, J = 7.0Hz, 1H), 7.55 – 7.46 (m, 4H), 5.33 (s, 2H), 3.70 (s, 3H), 2.50 (s, 3H), 2.41(s, 3H), 2.19 (s, 3H); HRMS (ESI) calculated for C 17 H 20 N7O2 + [M+H]+ , 354.1673;found, 354.1690. III-10: Yield: 41.4%, bright yellow liquid. 1 H NMR (400 MHz, CDCl3) δ 8.69 (s, 1H), 7.65– 7.58 (m, 1H), 7.58 – 7.40 (m, 3H), 5.35 (s, 2H), 3.70 (s, 3H), 2.53 (d, J =3.1 Hz, 6H), 2.22 (s, 3H); HRMS (ESI) calculated for C 17 H 20 N7O2 + [M+H] + ,354.1673; found, 354.1699. III-11: Yield: 41.0%, yellow solid, mp: 94-96 ℃; 1 H NMR (400 MHz, CDCl3) δ 8.99(d, J = 1.4 Hz, 1H), 8.50 – 8.47 (m, 2H), 7.50 – 7.46 (m, 1H), 7.31 – 7.27(m, 1H), 7.25 (s, 1H), 5.45 (d, J = 1.4 Hz, 2H), 3.70 (s, 3H), 2.14 (s, 3H);HRMS (ESI) calculated for C 15 H 15 FN7O2 + [M+H] + , 344.1266; found, 344.1222. III-12: Yield: 59.1%, yellow solid, mp: 120-122 ℃; 1 H NMR (400 MHz, CDCl3) δ8.42 – 8.33 (m, 2H), 7.59 (dd, J= 8.1, 1.3 Hz, 1H), 7.43 (t, J = 8.0 Hz,1H), 7.37 – 7.33 (m, 1H), 5.53 (s, 2H), 3.68 (s, 3H), 2.46 (s, 3H), 2.12 (s,3H); HRMS (ESI) calculated for C 16 H 17 FN7O2 + [M+H] + , 358.1423; found, 358.1449. III-13: Yield: 66.3%, white solid, mp: 121-122 ℃; 1 H NMR (400 MHz, CDCl3) δ8.53 – 8.25 (m, 2H), 7.51 – 7.41 (m, 1H), 7.31 – 7.28 (m, 1H), 7.26 – 7.25(m, 1H), 5.45 (d, J = 1.4 Hz, 2H), 3.69 (s, 3H), 2.77 (q, J = 7.5 Hz, 2H),2.09 (s, 3H), 1.07 (t, J = 7.5 Hz, 3H). III-14: Yield: 34.6%, yellow solid, mp: 135-137 ℃; 1 H NMR (400 MHz, CDCl3) δ8.76 (d, J = 1.4 Hz, 1H), 8.48 (d, J = 1.4 Hz, 1H), 7.58 – 7.36 (m, 1H), 7.35– 7.22 (m, 2H), 5.43 (d, J = 1.5 Hz, 2H), 3.70 (s, 3H), 2.12 (s, 3H); HRMS(ESI) calculated for C 15 H 14 ClFN7O2 + [M+H] +, 378.0877; found, 378.0883. III-15: Yield: 35.6%, brown solid, mp: 102-104 ℃; 1 H NMR (400 MHz, CDCl3) δ8.24 (d, J = 6.8 Hz, 1H), 7.52 – 7.42 (m, 1H), 7.32 – 7.22 (m, 2H), 5.42 (s, 2H), 3.68 (s, 3H), 2.50 (d, J = 10.2 Hz, 3H), 2.40 (d, J = 14.2 Hz, 3H), 2.09(s, 3H); HRMS (ESI) calculated for C 17 H 19 FN7O2 + [M+H] + , 372.1579; found, 372.1505. III-16: Yield: 42.3%, yellow solid, mp: 76-78 ℃; 1 H NMR (400 MHz, CDCl3) δ 8.65(s, 1H), 7.52 – 7.42 (m, 1H), 7.32 – 7.20 (m, 2H), 5.42 (d, J = 1.5 Hz, 2H),3.69 (s, 3H), 2.52 (d, J = 8.3 Hz, 6H), 2.12 (s, 3H); HRMS (ESI) calculated for C 17 H 19 FN7O2 + [M+H] + , 372.1579; found, 372.1520. III-17: Yield: 42.2%, bright yellow liquid; 1H NMR (400 MHz, CDCl3) δ 7.52 – 7.41 (m,1H), 7.30 – 7.21 (m, 2H), 5.41 (s, 2H), 3.68 (s, 3H), 2.47 (d, J = 6.4 Hz,6H), 2.35 (s, 3H), 2.08 (s, 3H); HRMS (ESI) calculated for C 18 H 21 FN7O2 + [M+H] + ,386.1736; found, 386.1757. III-18: Yield: 45.1%, yellow solid, mp: 83-85 ℃; 1 H NMR (400 MHz, CDCl3) δ 8.94(d, J = 1.5 Hz, 1H), 8.44 – 8.38 (m, 2H), 7.54 (dd, J = 8.1, 1.3 Hz, 1H), 7.37 (t, J = 8.0 Hz, 1H), 7.27 (dd, J = 8.0, 1.3 Hz, 1H), 5.44 (s, 2H), 3.63(s, 3H), 2.09 (s, 3H); HRMS (ESI) calculated for C 15 H 15 ClN7O2 + [M+H] + , 360.0969;found, 360.0969. III-19: Yield: 44.2%, brown solid, mp: 119-121 ℃; 1 H NMR (400 MHz, CDCl3) δ8.44 – 8.33 (m, 2H), 7.79 (dd, J = 7.7, 1.7 Hz, 1H), 7.43 – 7.29 (m, 2H), 5.53 (s, 2H), 3.68 (s, 3H), 2.46 (d,J = 0.6 Hz, 3H), 2.13 (s, 3H); HRMS(ESI) calculated for C 16 H 17 ClN7O2 + [M+H] + , 374.1127; found, 374.1182. III-20: Yield: 32.9%, yellow solid, mp: 162-163 ℃; 1 H NMR (400 MHz, CDCl3) δ8.79 (d, J = 1.4 Hz, 1H), 8.47 (d, J = 1.4 Hz, 1H), 7.53 – 7.30 (m, 3H), 5.49(s, 2H), 3.71 (s, 3H), 2.14 (s, 3H); HRMS (ESI) calculated for C 15 H 14 C l2 N7O2 + [M+H] + , 394.0581; found, 394.0510. III-21: Yield: 50.1%, bright yellow liquid; 1 H NMR (400 MHz, CDCl3) δ 8.23 ​​(s, 1H), 7.77(dd, J = 7.7, 1.6 Hz, 1H), 7.42 – 7.30 (m, 2H), 5.51 (s, 2H), 3.68 (s, 3H), 2.50 (d, J = 7.6 Hz, 3H), 2.40 (d, J = 12.0 Hz, 3H), 2.11 (s, 3H); HRMS (ESI)calculated for C 17 H 19 ClN7O2 + [M+H] + , 388.1284; found, 388.1221. III-22: Yield: 38.1%, white solid, mp: 69-71 ℃; 1 H NMR (400 MHz, CDCl3) δ 8.67(s, 1H), 7.65 – 7.56 (m, 1H), 7.49 – 7.29 (m, 2H), 5.48 (s, 2H), 3.69 (s,3H), 2.52 (d, J = 7.9 Hz, 6H), 2.14 (s, 3H); HRMS (ESI) calculated forC 17 H 19 ClN7O2 + [M+H] + , 388.1284; found, 388.1240. III-23: Yield: 43.6%, bright yellow liquid; 1 H NMR (400 MHz, CDCl3) δ 7.60 (d, J = 8.6Hz, 1H), 7.39 (d, J = 8.1 Hz, 1H), 7.26 – 7.19 (m, 1H), 4.88 (s, 2H), 3.71(s, 3H), 2.60 (s, 3H), 2.47 (s, 9H); HRMS (ESI) calculated for C 18 H 21 ClN7O2 + [M+H] + , 402.1440; found, 402.1462. III-24: Yield: 44.1%, yellow solid, mp: 142-144 ℃; 1 H NMR (400 MHz, CDCl3) δ9.02 (s, 1H), 8.52 – 8.45 (m, 2H), 7.80 (ddf, J= 6.7, 2.6 Hz, 1H), 7.41 –7.32 (m, 2H), 5.52 (s, 2H), 3.70 (s, 3H), 2.17 (s, 3H); HRMS (ESI) calculatedfor C 15 H 15 BrN7O2 + [M+H] + , 404.0418; found, 404.0418. III-25: Yield: 55.2%, yellow solid, mp: 114-116 ℃; 1 H NMR (400 MHz, CDCl3) δ8.44 – 8.33 (m, 2H), 7.79 (dd, J = 7.7, 1.7 Hz, 1H), 7.43 – 7.29 (m, 2H),5.53 (s, 2H), 3.68 (s, 3H), 2.46 (s, 3H), 2.13 (s, 3H); HRMS (ESI) calculated for C 16 H 17 BrN7O2 + [M+H] + , 418.0622; found, 418.0620. III-26: Yield: 39.8%, yellow solid, mp: 190-192 ℃; 1 H NMR (400 MHz, CDCl3) δ8.80 (d, J = 1.4 Hz, 1H), 8.47 (d, J = 1.3 Hz, 1H), 7.79 (dd, J = 5.7, 3.6Hz, 1H), 7.43 – 7.32 (m, 2H), 5.49 (s, 2H), 3.71 (s, 3H), 2.15 (s, 3H); HRMS(ESI) calculated for C 15 H 14 BrClN7O2 + [M+H] +, 438.0076; found, 438.0087. III-27: Yield: 46.6%, yellow solid, mp: 71-73 ℃; 1 H NMR (400 MHz, CDCl3) δ 8.30– 8.21 (m, 1H), 7.78 (dd, J = 7.7, 1.7 Hz, 1H), 7.42 – 7.29 (m, 2H), 5.51 (s, 2H), 3.68 (s, 3H), 2.52 (d, J = 13.5 Hz, 3H), 2.42 (d, J = 14.2 Hz, 3H), 2.11(s, 3H); HRMS (ESI) calculated for C 17 H 19 BrN7O2 + [M+H] + , 432.0768; found,432.0768. III-28: Yield: 47.8%, bright yellow liquid; 1 H NMR (400 MHz, CDCl3) δ 8.23 ​​(s, 1H), 7.77(d, J = 7.4 Hz, 1H), 7.42 – 7.29 (m, 2H), 5.51 (s, 2H), 3.68 (s, 3H), 2.49(s, 3H), 2.39 (s, 3H), 2.11 (s, 3H); HRMS (ESI) calculated for C 17 H 19 BrN7O2 + [M+H] + , 432.0779; found, 432.0724. III-29: Yield: 32.1%, yellow solid, mp: 101-103 ℃; 1H NMR (400 MHz, CDCl3) δ9.07 – 9.02 (m, 1H), 8.52 – 8.44 (m, 2H), 7.44 – 7.34 (m, 2H), 7.24 (t, 1H),5.32 (s, 2H), 3.78 – 3.67 (m, 3H), 2.57 (s, 3H), 2.21 – 2.17 (m, 3H); HRMS(ESI) calculated for C 16 H 18 N7O2 + [M+H] + , 340.1517; found, 340.1527. III-30: Yield: 40.1%, yellow solid, mp: 118-120 °C; 1 H NMR (400 MHz, CDCl3) δ8.42 – 8.34 (m, 2H), 7.43 – 7.32 (m, 2H), 7.28 – 7.21 (m, 1H), 5.31 (s, 2H), 3.69 (s, 3H), 2.54 (s, 3H), 2.47 (s, 3H), 2.16 (s, 3H); HRMS (ESI) calculated for C 17 H 20 N7O2 + [M+H] + , 354.1673; found, 354.1646. III-31: Yield: 63.1%, yellow solid, mp: 119-120 °C; 1 H NMR (400 MHz, CDCl3) δ8.42 – 8.31 (m, 2H), 7.38 (d, J = 6.5 Hz, 2H), 7.30 – 7.22 (m, 1H), 5.31 (s,2H), 3.69 (s, 3H), 2.83 – 2.73 (m, 2H), 2.53 (s, 3H), 2.15 (s, 3H), 1.08 (t, J = 7.4 Hz, 3H). III-32: Yield: 32.1%, yellow solid, mp: 175-177 ℃; 1 H NMR (400 MHz, CDCl3) δ8.82 (d, J = 1.5 Hz, 1H), 8.48 (d, J = 1.5 Hz, 1H), 7.45 – 7.35 (m, 2H), 7.27– 7.19 (m, 1H), 5.30 (s, 2H), 3.72 (s, 3H), 2.56 (s, 3H), 2.16 (s, 3H); HRMS(ESI) calculated for C 16 H 17 ClN7O2 + [M+H] + , 374.1127; found, 374.1112. III-33: Yield: 48.8%, yellow solid, mp: 128-130 ℃; 1 H NMR (400 MHz, CDCl3) δ8.70 (s, 1H), 7.37 (d, J = 4.9 Hz, 2H), 7.22 (t, J = 4.6 Hz, 1H), 5.29 (s,2H), 3.70 (s, 3H), 2.65 – 2.40 (m, 9H), 2.17 (s, 3H); HRMS (ESI) calculated for C 18 H 22 N7O2 + [M+H] + , 368.1830; found, 368.1806. III-34: Yield: 45.6%, brown solid; mp: 109-111 ℃; 1H NMR (400 MHz, CDCl3) δ9.11 – 9.07 (m, 1H), 8.53 – 8.45 (m, 2H), 7.54 – 7.48 (m, 1H), 7.47 – 7.38(m, 2H), 7.24 – 7.17 (m, 1H), 5.18 (s, 2H), 4.05 (s, 3H), 3.85 (s, 3H), 2.27(s, 3H). III-35: Yield: 44.5%, yellow solid, mp: 109-111 ℃; 1 H NMR (400 MHz, CDCl3) δ8.45 – 8.34 (m, 2H), 7.51 – 7.33 (m, 3H), 7.23 – 7.17 (m, 1H), 5.13 (s, 2H), 4.04 (s, 3H), 3.83 (s, 3H), 2.55 (s, 3H), 2.27 (s, 3H); HRMS (ESI) calculated for C 18 H 21 N4O4 + [M+H] + , 357.1558; found, 357.1555. III-36: Yield: 37.6%, bright yellow liquid; 1 H NMR (400 MHz, CDCl3) δ 8.88 – 8.83 (m,1H), 8.52 – 8.47 (m, 1H), 7.53 – 7.36 (m, 3H), 7.23 – 7.16 (m, 1H), 5.17 (s,2H), 4.04 (s, 3H), 3.85 (s, 3H), 2.24 (s, 3H). III-37: Yield: 51.1%, yellow solid, mp: 75-77 ℃; 1 H NMR (400 MHz, CDCl3) δ 8.26(d, J= 13.1 Hz, 1H), 7.51 – 7.34 (m, 3H), 7.23 – 7.16 (m, 1H), 5.12 (s, 2H), 4.04 (s, 3H), 3.83 (s, 3H), 2.56 – 2.47 (m, 6H), 2.25 (s, 3H); HRMS (ESI)calculated for C 19 H 23 N4O4 + [M+H] + , 371.1714; found, 371.1790. III-38: Yield: 64.3%, yellow solid, mp: 74-76 ℃; 1 H NMR (400 MHz, CDCl3) δ 8.24(s, 1H), 7.51 – 7.34 (m, 3H), 7.19 (dd, J = 7.2, 1.8 Hz, 1H), 5.12 (s, 2H), 4.04 (s, 3H), 3.83 (s, 3H), 2.50 (d, J = 6.8 Hz, 6H), 2.25 (s, 3H); HRMS(ESI) calculated for C 19 H 23 N4O4 + [M+H] + , 371.1714; found, 371.1723. III-39: Yield: 32.3%, yellow solid, mp: 139-141 ℃; 1 H NMR (600 MHz, CDCl3) δ8.75 (s, 1H), 7.52 – 7.48 (m, 1H), 7.45 – 7.36 (m, 2H), 7.21 – 7.16 (m, 1H), 5.15 (s, 2H), 4.04 (s, 3H), 3.84 (s, 3H), 2.53 (d, J = 7.1 Hz, 6H), 2.25 (s,3H); HRMS (ESI) calculated for C 19H 23 N4O4 + [M+H] + , 371.1714; found, 371.17123. III-40: Yield: 55.1%, yellow solid, mp: 98-100 ℃; 1 H NMR (400 MHz, CDCl3) δ 7.51– 7.33 (m, 3H), 7.19 (d, J = 7.4 Hz, 1H), 5.11 (s, 2H), 4.04 (s, 3H), 3.83(s, 3H), 2.53 – 2.46 (m, 9H), 2.24 (s, 3H); HRMS (ESI) calculated forC 20 H 25 N4O4 + [M+H] + , 385.1817; found, 385.1880. III-41 Yield: 52.1%, yellow solid, mp: 69-71 ℃; 1 H NMR (400 MHz, CDCl3) δ 9.11(d, J = 1.5 Hz, 1H), 8.58 – 8.45 (m, 2H), 7.58 – 7.51 (m, 1H), 7.46 – 7.34(m, 3H), 5.35 (s, 2H), 3.80 (s, 3H), 3.77 (s, 3H), 2.35 (s, 3H); HRMS (ESI)calculated for C 16 H 19 N4O4 + [M+H] + , 331.1401; found, 331.1401. III-42 Yield: 64.5%, bright yellow liquid; 1H NMR (600 MHz, CDCl3) δ 7.74 – 7.71 (m,1H), 7.64 – 7.60 (m, 1H), 7.38 – 7.34 (m, 2H), 7.17 – 7.13 (m, 1H), 6.49 (s,1H), 5.27 (s, 2H), 4.98 (s, 3H), 3.84 – 3.81 (m, 3H), 3.72 – 3.69 (m, 3H),2.70 (s, 3H); HRMS (ESI) calculated for C 17 H 21 N4O4 + [M+H] + , 345.1588; found, 345.1555. III-43 Yield: 33.5%, white solid, mp: 106-108 °C; 1 H NMR (400 MHz, CDCl3) δ 8.91– 8.87 (m, 1H), 8.54 – 8.49 (m, 1H), 7.57 – 7.49 (m, 1H), 7.43 – 7.34 (m,3H), 5.34 (s, 2H), 3.78 (d, J = 14.9 Hz, 6H), 2.32 (s, 3H). III-44 Yield: 47.2%, yellow solid, mp: 76-78 ℃; 1 H NMR (400 MHz, CDCl3) δ 8.25(s, 1H), 7.58 – 7.49 (m, 1H), 7.42 – 7.31 (m, 3H), 5.29 (s, 2H), 3.76 (d, J =13.4 Hz, 6H), 2.52 (d, J = 3.0 Hz, 6H), 2.34 (s, 3H); HRMS (ESI) calculated for C 18 H 23 N4O4 + [M+H] + , 359.1714; found, 359.1722. III-45 Yield: 42.5%, yellow solid, mp: 80-82 ℃; 1 H NMR (600 MHz, CDCl3) δ 8.75(s, 1H), 7.54 (s, 1H), 7.39 – 7.31 (m, 3H), 5.31 (s, 2H), 3.79 (s, 3H), 3.76(s, 3H), 2.53 (s, 6H), 2.33 (s, 3H); HRMS (ESI) calculated for C 18 H 23 N4O4 + [M+H] + , 359.1714; found, 359.1712. III-46 Yield: 40.6%, yellow solid, mp: 69-71 ℃; 1 H NMR (400 MHz, CDCl3) δ 7.57– 7.49 (m, 1H), 7.41 – 7.32 (m, 3H), 5.28 (s, 2H), 3.76 (d, J = 14.1 Hz, 6H),2.56 – 2.48 (m, 9H), 2.33 (s, 3H); HRMS (ESI) calculated for C 19 H 25 N4O4 + [M+H] + ,373.1817; found, 373.1879. Biological test cases Test Example 1: Antifungal activity of the target compound against eight plant pathogenic fungi. Experimental materials: Test reagent: Compounds of this invention Positive controls: azoxystrobin, tetrazolium Test strain: Apple rot pathogen (Waltz of evil , Vm ), rapeseed sclerotium ( Sclerotinia skeletons , Ss ), tomato gray mold ( Botrytis cinerea , B,c ), wheat scab ( Fusarium grasses , Fg Rice curvularia ( ) Curvularia lunate , C.l ), Phytophthora capsici ( Phytophthora capsicum , PC Apple anthracnose bacteria ( Colletotrichum gloeosporioides , Cg ), tomato early blight pathogen ( Alternaria solani , As ).

[0071] Preparation of Potato Agar-Dextrose Medium (PDA): Weigh 1600 g of peeled potatoes, cut them into small pieces, add pure water and boil the potato pieces for about 30 min. Then, filter through eight layers of gauze, collect the filtrate, heat it, and add 120 g of agar and 200 g of glucose in sequence, stir well and let it dissolve completely. Add pure water to make up to 8000 mL, stir well and let it dissolve completely. Autoclave at 121 ℃ for 30 min.

[0072] Experimental methods: This experiment used the mycelial growth rate method to determine the antifungal activity of all target compounds against eight plant pathogenic fungi. The required amount of test compound was weighed and dissolved in DMSO (1 mL). The prepared solutions were then added to sterilized culture media, mixed thoroughly, and prepared into 20 mL solutions. g / mL of virus-containing medium. Prepare virus-containing medium at 15 mL per dish. Using a 6 mm inner diameter punch, punch the cultured pathogenic bacteria plate along the edge to create discs containing mycelia. Then, using aseptic technique, inoculate each mycelial disc upside down onto the corresponding drug-containing medium, placing one mycelial disc per dish. Seal the dishes with sealing film or plastic wrap and incubate them upside down in a 26 ± 1 ℃ biochemical incubator. When the control group reaches approximately two-thirds of the dish diameter, measure the diameter of each treated colony using the cross-sectional method. Perform three parallel experiments for each compound, and take the average value for statistical analysis.

[0073] Compounds with good initial screening activity were selected for EC determination. 50 Value. Based on the linear regression relationship between the probability value (y) and the logarithm of the mass concentration (x) of the mycelial growth inhibition rate, the toxicity regression equation of the agent was calculated as y = a + bx, and the inhibition median concentration (EC50) was determined. 50 ) and correlation coefficient (R2).

[0074] Experimental results: The results of the antibacterial activity of the compounds are shown in Table 1.

[0075] Table 1 shows the inhibitory activity of the compounds against eight plant pathogenic fungi at a concentration of 20 μg / mL. a The mean of three repeated measurements ± standard error; As shown in Table 1, the inhibitory activity of all target compounds against eight plant pathogenic fungi at 20 μg / mL was determined using the mycelial growth rate method. The results showed that many compounds exhibited significant inhibitory activity against *Pseudomonas aeruginosa*, *Pseudomonas sclerotiorum*, and *Botrytis cinerea*. The compounds showed 80% inhibitory activity against Sclerotinia sclerotiorum, the causal agent of rapeseed rot, with compounds III-8, III-10, III-14, III-16, III-18, III-24, III-29, III-30, III-33–III-37, III-39, III-41–III-43, and III-45 exhibiting 100% inhibitory activity against the causal agent.

[0076] For pyrazine derivatives III-5–III-33 containing a tetrazolone structure, except when R1 is Br, the target compounds exhibit the highest antifungal activity when R1 is H, F, Cl, or CH3. For example, III-8 (R1= H, R2=3,5-diCH3), III-10 (R1= H, R2= 5,6-diCH3), III-16 (R1= F, R2= 5,6-diCH3), and III-30 (R1=CH3, R2= 3-CH3) all showed 100% inhibition against *Sclerotinia sclerotiorum*, while III-21 (R1= Cl, R2= 3,6-diCH3) showed an inhibition rate of 89.3% against *Sclerotinia sclerotiorum*.

[0077] For the pyrazine derivatives III-34–III-46 that do not contain a tetrazolone structure, except for compounds III-37, III-38, III-39, and III-42, the other compounds all showed antifungal activity of more than 75% against *Agrostis chinensis* and *Sclerotium oxysporum*, especially most of the compounds showed 100% inhibitory activity against *Sclerotium oxysporum*, such as III-34–III-37, III-39, III-41–III-43, and III-45.

[0078] Table 2. EC50 of some compounds inhibiting plant pathogenic fungi 50 value a 95% confidence interval As shown in Table 2, to further evaluate the antifungal activity of the target compounds, compounds with an inhibition rate greater than 90% at 20 μg / mL were selected against specific pathogenic fungi.50 The measurements were taken.

[0079] Compound III-14 exhibits the best activity against *Sclerotinia sclerotiorum*, the causal agent of rapeseed sclerotiorum infection, with its EC50... 50 The concentration was 0.003 mg / L, significantly lower than that of tetrazolium (0.133 mg / L) and azoxystrobin (0.779 mg / L). The antifungal activity of compounds III-33 and III-36 was also significantly lower than that of tetrazolium (EC). 50 0.133 mg / L) and azoxystrobin (EC) 50 (0.779 mg / L), its EC 50 The concentrations were 0.039 mg / L and 0.024 mg / L, respectively. Other compounds, except for III-11, III-16, III-18, III-24, and III-30, exhibited activities comparable to tetrazolium and azoxystrobin. Some compounds also showed excellent antifungal activity against tomato gray mold.

[0080] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A compound of formula I, or a pesticide-acceptable salt thereof, I in, S1 is selected from the following group: , , ; R1 is H or each of the following substituents independently selected from: halogen, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 haloalkyl, C1-C6 haloalkoxy; R2 is each of 0-3 substituents selected from the following group: -NH2, -NO2, -CN, halogen, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 haloalkyl, C1-C6 haloalkoxy, C3-C8 cycloalkyl, and C3-C8 heterocyclic alkyl containing 1-3 N, O or S atoms.

2. The compound according to claim 1, characterized in that, R2 is each of 1-3 substituents selected from the following group: -NH2, -NO2, -CN, halogen, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 haloalkyl, C1-C6 haloalkoxy, C3-C8 cycloalkyl, and C3-C8 heterocyclic alkyl containing 1-3 N, O, or S atoms.

3. The compound according to claim 1, characterized in that, R2 is each of 1-2 substituents selected from the group consisting of halogen, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 haloalkyl, and C1-C6 haloalkoxy.

4. The compound according to claim 1, characterized in that, R2 is each of 1-2 substituents selected from the group consisting of halogen, C1-C6 alkyl, C1-C6 alkoxy, C1-C6 haloalkyl, and C1-C6 haloalkoxy.

5. The compound according to claim 1, characterized in that, R2 is a halogen or a C1-C3 alkyl group.

6. The compound according to claim 1, characterized in that, The compounds are selected from the group consisting of: 。 7. A method for preparing the compound as described in claim 1, characterized in that, Includes the following steps: When the compounds of formula I are III-5 to III-33, the synthesis is as follows: In an inert solvent, compound III-4a is coupled with compound III-1 to prepare III-5 to III-33. When the compound of formula I is III-34 to III-40, the synthesis is as follows: In an inert solvent, compound III-4a is coupled with compound III-2 to prepare III-34~III-40. When the compounds of formula I are III-41 to III-46, the synthesis is as follows: In an inert solvent, compound III-4a is coupled with compound III-3 to prepare III-41 to III-46. Wherein, R1 and R2 are as defined in claim 1.

8. A composition, characterized in that, Include: (i) the compound of claim 1 or a pharmaceutically acceptable salt thereof; and (ii) Pharmaceutically acceptable carriers.

9. Use of the compound as claimed in claim 1, characterized in that, The uses include: (a) Used in the preparation of bactericides; (b) Used as a bactericide.

10. A method for sterilization, characterized in that, The method comprises contacting crops with fungal diseases with an effective amount of the compound as claimed in claim 1 or the composition as claimed in claim 8.

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