N-(1-Arylpyrazolylmethyl-substituted pyridin-2-ylidene) amide compounds, preparation methods and applications thereof

Abstract

The present invention discloses N-(1-arylpyrazolylmethyl-substituted pyridin-2-ylidene)amide compounds, a preparation method thereof and an application thereof. The general structural formula of the compounds is shown in Formula I, wherein R 1 is hydrogen, a C1-C5 saturated or unsaturated aliphatic hydrocarbon group, a halogen, a haloalkyl group, a cyano group or a nitro group, etc. R 2 is hydrogen, a halogen mono-substituted or multi-substituted at the 1, 2 or 3 position, a hydroxyl group, a methoxy group, a haloalkyl group, a cyano group or a nitro group, etc. R 3 is a haloalkyl group, a C1-C5 alkyl group, a C1-C5 alkoxymethyl group, an aryl group or a substituted aryl group, etc. Insecticidal activity experiments show that the arylpyrazole compounds shown in Formula (I) have high control efficacy against crop pests such as planthoppers and diamondback moths, and can be used as plant insecticides.

Description

Technical Field

[0001] The present invention belongs to the technical field of pesticides, and particularly relates to N-(1-arylpyrazolylmethyl-substituted pyridin-2-ylidene) amide compounds, a preparation method thereof, and an application thereof. Background Art

[0002] Neonicotinoid insecticides are one of the most influential types of agricultural insecticides in the past 30 years and have played an important role in crop protection. However, the safety issues of traditional neonicotinoid insecticides for bees have attracted increasing attention. The replacement of these varieties is inevitable, and it is urgent to develop new insecticides that are safe for environmental organisms such as bees. In recent years, the successive market launches of flupyradifurone, triflumezopyrim, flupyrimin, etc. have proved the practical feasibility of developing neonicotinoid insecticides that are safe for bees.

[0003] Arylpyrazole is a structural unit widely present in many pesticide varieties, especially insecticides. Therefore, in the present invention, an arylpyrazole unit is introduced into amido pyridine to synthesize a series of compounds of general formula I, which have good insecticidal activity and are expected to be used in the field as agricultural insecticides. Summary of the Invention

[0004] The object of the present invention is to provide a class of N-(1-arylpyrazolylmethyl-substituted pyridin-2-ylidene) amide compounds, a preparation method thereof, and an application as an insecticide.

[0005] A class of N-(1-arylpyrazolylmethyl-substituted pyridin-2-ylidene) amide compounds or a pharmaceutically acceptable salt thereof provided by the present invention has a structural general formula as shown in formula I:

[0006]

[0007] Wherein:

[0008] R 1 is hydrogen, a C1-C5 saturated or unsaturated aliphatic hydrocarbon group, a halogen, a haloalkyl group, a cyano group, a nitro group, etc.

[0009] R 2 is hydrogen, a single-substituted or polysubstituted halogen, a hydroxyl group, a methoxy group, a haloalkyl group, a cyano group, a nitro group, etc. at the 1, 2, or 3 position.

[0010] R 3 is a haloalkyl group, a C1-C5 alkyl group, a C1-C5 alkoxymethyl group, an aryl group (such as: phenyl, pyridyl, imidazolyl, oxazolyl, thiazolyl, pyrazolyl), a substituted aryl group, etc., and the substituents in the substituted aryl group may be a halogen, a C1-C5 alkyl group, a C1-C5 alkoxy group, an aryloxy group (such as: phenoxy, pyridyloxy), etc.

[0011] Further, the R 1 is allyl, propargyl, or monofluoromethyl, difluoromethyl, trifluoromethyl.

[0012] Preferably, the R 1 is hydrogen, trifluoromethyl, difluoromethyl.

[0013] Preferably, the R 2 is hydrogen or halogen.

[0014] Preferably, the R 3 is trifluoromethyl, difluoromethyl, pentafluoroethyl, pyrazolyl, methoxymethyl.

[0015] More preferably, the R 1 is trifluoromethyl, more preferably the R 2 is halogen, and more preferably the R 3 is methoxymethyl.

[0016] The preparation method of the arylpyrazole compound represented by the general formula of the formula I provided by the present invention includes the following steps:

[0017] 1) Pyrazole acyl chloride reacts with ethanol to form a pyrazole acid ester represented by the formula II;

[0018]

[0019] 2) The pyrazole acid ester represented by the formula II is reduced to obtain a compound represented by the general formula of the formula III;

[0020]

[0021] 3) The compound represented by the general formula of the formula III is reacted under the action of a chlorinating reagent to form a compound represented by the general formula of the formula IV;

[0022]

[0023] 4) 2-Aminopyridine reacts with acyl chloride or acid anhydride to form a compound represented by the general formula of the formula V.

[0024]

[0025]

[0026] 5) The compound represented by the general formula of the formula V and the compound represented by the general formula of the formula IV are reacted under the catalysis of a base to form a compound represented by the general formula of the formula I;

[0027] Among them, the R in the formula II, the formula III and the formula IV 1 is hydrogen, C1-C5 saturated or unsaturated aliphatic hydrocarbon group, halogen, haloalkyl, cyano, nitro, etc.

[0028] R2 is hydrogen, halogen mono- or poly-substituted at the 1, 2, or 3 positions, hydroxy, methoxy, haloalkyl, cyano, nitro, etc.

[0029] R in formula V 3 is trifluoromethyl, trichloromethyl, chloromethyl, C1-C5 alkyl, C1-C5 alkoxymethyl, aryl (such as phenyl, pyridyl, imidazolyl, oxazolyl, thiazolyl, pyrazolyl), substituted aryl, etc. The substituents in the substituted aryl can be halogen, C1-C5 alkyl, C1-C5 alkoxy, aryloxy (such as phenoxy, pyridyloxy), etc.

[0030] Preferred R 1 is hydrogen, trifluoromethyl, difluoromethyl. Preferred R 2 is hydrogen or halogen; Preferred R 3 is trifluoromethyl, difluoromethyl, pyrazolyl, methoxymethyl.

[0031] More preferred R 1 is trifluoromethyl. More preferred R 2 is halogen. More preferred R 3 is methoxymethyl.

[0032] The reaction in step 1) is carried out in a solvent, and the solvent can be anhydrous ethanol; the reaction temperature of the reaction is room temperature (25 °C). The anhydrous ethanol in step 1) is in excess.

[0033] The reaction in step 2) is carried out in a solvent, and the solvent can be anhydrous tetrahydrofuran; the reaction temperature of the reaction is 0 °C; the molar ratio of the pyrazolecarboxylate shown in formula II to the reducing agent lithium aluminum hydride in step 2) is (1:1)-(1:2).

[0034] The reaction in step 3) is carried out in a solvent, and the solvent can be dichloromethane; the reaction temperature of the reaction is 40 °C; the molar ratio of the compound shown in the general formula of formula III to the chlorinating reagent in step 3) is (1:1.2)-(1:2.5).

[0035] The reaction in step 4) is carried out in a solvent, and the solvent can be dichloromethane; the reaction temperature of the reaction is room temperature (25 °C); the molar ratio of 2-aminopyridine to the carboxylic acid in step 4) is (1:1)-(1:1.1).

[0036] The reaction in step 5) is carried out in a solvent, and the solvent can be acetonitrile. The reaction temperature of the reaction is 80 °C; the base used in the reaction can specifically be potassium carbonate. The molar ratio of the compound shown in the general formula of formula V to the compound shown in the general formula of formula IV in step 5) is (1:1)-(1:1.1).

[0037] Another object of the present invention is to provide the use of the arylpyrazole compounds represented by the general formula of Formula I.

[0038] The use of the arylpyrazole compounds represented by the general formula of Formula I provided by the present invention is that the compounds represented by the general formula of Formula I or their pharmaceutically acceptable salts or pharmaceutical compositions containing any one of them can be used to prepare plant insecticides. The plant insecticides are insecticides for killing homopterous pests and / or lepidopterous pests.

[0039] Another object of the present invention is to provide a plant insecticidal drug or preparation.

[0040] The plant insecticidal drug or preparation provided by the present invention has an active ingredient which is an arylpyrazole compound represented by the general formula of Formula I or its pharmaceutically acceptable salt.

[0041] The mass percentage content of the active ingredient in the insecticidal drug or preparation is 0.01% - 99.99%.

[0042] The insecticide can be processed into any acceptable dosage form as needed. For example, it can be a suspension, an emulsion, an aerosol, a wettable powder, an emulsifiable concentrate, a granule.

[0043] Examples of the preparation methods of the dosage forms are as follows:

[0044] Preparation of suspension: In a common formulation, the content of the active component is 5% - 35%. Using water as the medium, the technical material, a water dispersant, a suspending agent, an antifreezing agent, etc. are added to a grinding machine and ground to prepare a suspension.

[0045] Preparation of wettable powder: According to the formulation requirements, the technical material, various surfactants and solid diluents, etc. are fully mixed and then superfine pulverized to obtain a wettable powder product with a predetermined content. To prepare a wettable powder suitable for spraying, a mixture can also be composed of the technical material and a finely ground solid powder such as clay, inorganic silicate, carbonate, as well as a wetting agent, a binder and / or a dispersant.

[0046] Preparation of emulsifiable concentrate: According to the formulation requirements, the active ingredient is dissolved in an organic solvent, and an emulsifier and other auxiliaries are added for processing. The solvent can be toluene, xylene, methanol, etc., and a cosolvent is also contained when needed; other auxiliaries include stabilizers, penetrants and corrosion inhibitors, etc.

[0047] The compounds represented by the general formula of Formula I provided by the present invention and the insecticidal drugs or preparations with this compound as the active ingredient can control and eliminate a wide range of pests, including sucking insects, biting insects and other plant pests, pests in stored grains, and sanitary pests causing health hazards, etc.

[0048] Examples of pests are as follows:

[0049] Homoptera pests include pests of Aphididae, Aleyrodidae, Delphacidae, Psyllidae, Cicadellidae and Coccidae. Specific examples of Aphididae pests can be Aphis gossypii, Aphis craccivora, Myzus persicae, Hyalopterus amygdali, Lipaphis erysimi, Brevicoryne brassicae; specific examples of Delphacidae pests can be Nilaparvata lugens, Sogatella furcifera; specific examples of Aleyrodidae pests can be Bemisia tabaci; specific examples of Cicadellidae pests can be Nephotettix cincticeps; specific examples of Coccidae pests can be Unaspis yanonensis.

[0050] Lepidoptera pests include pests of Noctuidae and Plutellidae. Specific examples of Noctuidae pests can be Spodoptera exigua, Spodoptera litura, Helicoverpa armigera; specific examples of Plutellidae pests can be Plutella xylostella.

[0051] The plant insecticidal drug or preparation provided by the present invention can be used to control plant pests. It has a special effect on piercing-sucking pests and scraping-sucking mouthpart pests, such as various aphids, planthoppers, leafhoppers, whiteflies, thrips, and is highly effective against Helicoverpa armigera and Spodoptera exigua.

[0052] Another object of the present invention is to provide a method for controlling plant pests.

[0053] The method for controlling plant pests provided by the present invention is to apply the plant insecticidal drug or preparation provided by the present invention on plant leaves and / or fruits and / or seeds, and in the environment where the plant leaves and / or fruits and / or seeds are growing or expected to grow; the mass percentage content of the active ingredient in the plant insecticidal drug or preparation is 0.01%-99.99%. The application concentration of the active ingredient of the plant insecticidal drug or preparation is 1-600 mg / L, preferably 3-50 mg / L.

[0054] Advantages of the present invention

[0055] The present invention provides arylpyrazole compounds with the structural general formula shown in Formula I, and their preparation methods and applications. The compounds have high insecticidal activity, and the preparation methods are simple, with good safety and low cost, greatly improving the practical application value of the compounds. Insecticidal activity experiments show that the arylpyrazole compounds shown in Formula (I) have high control effects on crop pests such as Nilaparvata lugens and Plutella xylostella, and can be used as plant insecticides. Specific embodiments

[0056] The arylpyrazole compounds of the present invention can be synthesized through the following reaction steps:

[0057]

[0058] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. The experimental methods without specific implementation conditions in the following embodiments are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer. Unless otherwise specified, percentages and parts are calculated by mass.

[0059] Taking (E)-N-(1-((1-phenyl-5-(trifluoromethyl)-1H-pyrazol-4-yl)methyl)pyridin-2(1H)-ylidene)trifluoroacetamide as an example, the preparation method of the arylpyrazole compound shown in formula (I) provided by the present invention will be illustrated.

[0060] Example 1 Synthesis of (E)-N-(1-((1-phenyl-5-(trifluoromethyl)-1H-pyrazol-4-yl)methyl)pyridin-2(1H)-ylidene)trifluoroacetamide (the compound in formula I where R 1 is trifluoromethyl, R 2 is H, and R 3 is trifluoromethyl):

[0061] (1) Synthesis of ethyl 1-phenyl-5-(trifluoromethyl)-1H-pyrazole-4-carboxylate

[0062] A magnetic stir bar was placed in a 100 mL round-bottom flask, and 0.023 mol of 1-phenyl-5-(trifluoromethyl)-1H-pyrazole-4-carboxylic acid and 20 mL of thionyl chloride (0.276 mol) were added. After addition, a reflux condenser was installed, and the mixture was heated to reflux for three hours until no white mist was generated at the reflux condenser outlet. Heating was stopped, and after cooling to room temperature, the excess thionyl chloride was removed by rotary evaporation to obtain a dark brown oily liquid, which was diluted with 20 mL of dichloromethane and reserved for use.

[0063] 30 mL (in excess) of absolute ethanol was added to a 250 mL round-bottom flask, and the dichloromethane solution of the product from the previous step was slowly added dropwise to the round-bottom flask through a dropping funnel. After the addition, the mixture was stirred at room temperature for 30 min. The solvent was removed by rotary evaporation, and the residue was purified by column chromatography to obtain ethyl 1-phenyl-5-(trifluoromethyl)-1H-pyrazole-4-carboxylate.

[0064] (2) Synthesis of (1-phenyl-5-(trifluoromethyl)-1H-pyrazol-4-yl)methanol

[0065] Place a magnetic stir bar in a 100 mL round-bottom flask, add 0.013 mol of ethyl 1-phenyl-5-(trifluoromethyl)-1H-pyrazole-4-carboxylate, and 30 mL of anhydrous tetrahydrofuran. Cool the mixture in an ice bath to below 5 °C, and add 578 mg of lithium aluminum hydride (0.0156 mol) to the round-bottom flask in portions. A large amount of gas is generated after the addition, and the solution becomes grayish-black and turbid. React the mixture in the ice bath for 1 hour, and then stop the reaction. Pour the reaction solution into water to quench the reaction, and extract it with a separatory funnel using ethyl acetate as the extractant, 30 mL each time, for three times. Combine the organic phases, and obtain the product (1-phenyl-5-(trifluoromethyl)-1H-pyrazol-4-yl)methanol by column chromatography.

[0066] (3) Synthesis of 4-(chloromethyl)-1-phenyl-5-(trifluoromethyl)-1H-pyrazole

[0067] Place a magnetic stir bar in a 100 mL round-bottom flask, add 0.01 mol of (1-phenyl-5-(trifluoromethyl)-1H-pyrazol-4-yl)methanol and 20 mL of dichloromethane. While stirring, add 0.87 mL of thionyl chloride (0.012 mol) and 1 drop of DMF to the round-bottom flask. Heat the mixture under reflux for two hours, and then stop heating. Rotate the evaporator to remove the solvent, and extract the residue with a separatory funnel using ethyl acetate as the extractant, 30 mL each time, for three times. Combine the organic phases, and obtain a yellow oily liquid by column chromatography with a yield of 82%.

[0068] The structure characterization data are as follows:

[0069] 1 H NMR (500 MHz, CDCl3) δ 7.77 (s, 1H), 7.52–7.38 (m, 5H), 4.65 (s, 2H)

[0070] (4) Synthesis of N-(pyridin-2-yl)trifluoroacetamide

[0071] Place a stirring device in a 100 mL round-bottom flask, add 2.82 g of 2-aminopyridine (0.03 mol) and 30 mL of dichloromethane. Add 2 drops of triethylamine to the flask, and slowly add 0.03 mol of trifluoroacetic anhydride dropwise under an ice bath. Remove the ice bath, and react the mixture at room temperature for 20 min, and then stop the reaction. Rotate the evaporator to remove the solvent, and extract the residue with a separatory funnel using ethyl acetate as the extractant, 30 mL each time, for three times. Combine the organic phases, and obtain a white solid by column chromatography with a yield of 44% and a melting point of 68-69 °C.

[0072] The structure characterization data are as follows:

[0073] 11H NMR (500 MHz, CDCl3) δ 9.87 (s, 1H), 8.34 (d, J = 4.9 Hz, 1H), 8.20 (d, J = 8.3 Hz, 1H), 7.82 (t, 1H), 7.24–7.17 (m, 1H)

[0074] (5) Synthesis of (E)-N-(1-((1-phenyl-5-(trifluoromethyl)-1H-pyrazol-4-yl)methyl)pyridin-2(1H)-ylidene)trifluoroacetamide

[0075] A stir bar was placed in a 100 mL round-bottom flask, 30 mL of the solvent acetonitrile was added, 0.002 mol of N-(pyridin-2-yl)trifluoroacetamide, 552 mg of anhydrous potassium carbonate (0.004 mol) and 0.002 mol of 4-(chloromethyl)-1-phenyl-5-(trifluoromethyl)-1H-pyrazole were added. The mixture was heated under reflux for 5 h and the reaction was stopped. The solvent was rotary evaporated, and the residue was extracted with a separatory funnel using ethyl acetate as the extractant, 30 mL each time, for three times. The organic phases were combined and purified by column chromatography to obtain a white solid with a yield of 70% and a melting point of 168 - 169 °C.

[0076] The structure characterization data are as follows:

[0077] 1 1H NMR (500 MHz, CDCl3) δ 8.56 (dd, J = 9.1, 1.4 Hz, 1H), 7.97 (s, 1H), 7.85 (dd, J = 6.7, 1.8 Hz, 1H), 7.79 (ddd, J = 9.0, 6.9, 1.8 Hz, 1H), 7.51–7.45 (m, 3H), 7.43–7.37 (m, 2H), 6.88 (td, J = 6.8, 1.4 Hz, 1H), 5.62 (s, 2H).

[0078] Example 2. Insecticidal activity test of the compounds of the present invention

[0079] Planthoppers belong to the pests of the order Hemiptera and have piercing-sucking mouthparts. Taking the brown planthopper (Nilaparvata lugens) as the test object, the spray method was used for the test.

[0080] Operation process: Weigh a certain mass of the technical material with an analytical balance (0.001 g), prepare a 1% stock solution with DMF, and then dilute it with distilled water containing 0.1% Tween-80 to the corresponding concentration for standby. Place the seedlings with two leaves and one heart in a petri dish with a bottom diameter of 3 cm, cover with white sand, stun the 3rd instar nymphs of brown planthoppers with CO2, and then place about 15 nymphs in each dish. Place them under the Potter spray tower for spraying, with 3 replicates for each concentration and a spraying volume of 2.5 mL. Investigate the mortality of brown planthoppers 1 day after treatment. Use the DMF solution without the agent as the blank control.

[0081] The diamondback moth belongs to the pests of Lepidoptera. The larvae have chewing mouthparts. Taking Plutella xylostella as the test object, the dipping method was used for the test.

[0082] Operation process: Weigh a certain mass of the technical material with an analytical balance (0.001 g), prepare a 1% mother liquor with DMF, and then dilute it with distilled water containing 0.1% Tween-80 to the corresponding concentration for standby. Take an appropriate amount of radish leaves, immerse them in the medicine for 10 s, then place them in a plastic petri dish lined with filter paper and let them dry naturally in the shade. Put 10 second-instar diamondback moth larvae in each dish and place them in an observation room at 22 °C with light (16 / 8 h). Observe after 2 days. Gently touch the insect body with a writing brush. If there is no response, it is regarded as a dead insect. Repeat 3 times, and use the DMF solution without the medicine as the blank control.

[0083] The results are shown in the table:

[0084]

[0085]

[0086]

[0087] The above embodiments have described the technical solutions of the present invention in detail. Obviously, the present invention is not limited to the described embodiments. Based on the embodiments of the present invention, those skilled in the art can also make various changes accordingly, but any changes equivalent or similar to the present invention fall within the protection scope of the present invention.

Claims

1. A compound represented by formula I, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition containing any one of them: Wherein: R 1 is hydrogen, a C1-C5 saturated or unsaturated aliphatic hydrocarbon group, a halogen, a haloalkyl group, a cyano group or a nitro group; R 2 is hydrogen, halogen, hydroxyl, methoxy, haloalkyl, cyano or nitro; wherein, when R 2 is hydrogen, halogen, hydroxyl, methoxy, haloalkyl, cyano or nitro, it is mono-substituted or multi-substituted at the 1, 2, and 3 positions of the benzene ring; R 3 is a haloalkyl group, a C1-C5 alkyl group, a C1-C5 alkoxymethyl group, a phenyl group, a pyridyl group, an imidazolyl group, an oxazolyl group, a thiazolyl group or a pyrazolyl group, wherein the phenyl group, pyridyl group, imidazolyl group, oxazolyl group, thiazolyl group and pyrazolyl group are optionally substituted by a halogen, a C1-C5 alkyl group, a C1-C5 alkoxy group or an aryloxy group.

2. The compound according to claim 1, wherein The R 1 is allyl, propargyl, or monofluoromethyl, difluoromethyl, or trifluoromethyl.

3. The compound according to claim 1, characterized in that, The R 2 is fluorine, chlorine, bromine, trifluoromethyl or difluoromethyl which is mono-substituted or multi-substituted at the 1, 2, and 3 positions of the benzene ring.

4. The compound according to claim 1, wherein The R 3 haloalkyl groups are trifluoromethyl, difluoromethyl, and pentafluoroethyl.

5. A method for preparing the compound according to claim 1, characterized in that, Comprising the following steps: 1) Pyrazole acyl chloride reacts with absolute ethanol to form a pyrazole acid ester represented by formula II; 2) The pyrazole acid ester represented by formula II is reduced to form a compound represented by the general formula of formula III; 3) The compound represented by the general formula of formula III reacts with a chlorinating reagent to form a compound represented by the general formula of formula IV; 4) 2-Aminopyridine reacts with an acyl chloride or an acid anhydride to form a compound represented by the general formula of formula V; 5) The compound represented by the general formula of formula V reacts with the compound represented by the general formula of formula IV under the catalysis of a base to form a compound represented by the general formula of formula I; Among them, R in Formula II, Formula III and Formula IV 1 is hydrogen, a C1-C5 saturated or unsaturated aliphatic hydrocarbon group, halogen, haloalkyl, cyano or nitro; R 2 is hydrogen, halogen, hydroxyl, methoxy, haloalkyl, cyano or nitro, and R 2 is halogen, hydroxyl, methoxy, haloalkyl, cyano or nitro, and is mono-substituted or multi-substituted at the 1, 2, 3 positions of the benzene ring; R in formula V 3 is trifluoromethyl, trichloromethyl, chloromethyl, C1-C5 alkyl, C1-C5 alkoxymethyl, phenyl, pyridyl, imidazolyl, oxazolyl, thiazolyl or pyrazolyl, wherein phenyl, pyridyl, imidazolyl, oxazolyl, thiazolyl, pyrazolyl are optionally substituted by halogen, C1-C5 alkyl, C1-C5 alkoxy or aryloxy.

6. The method according to claim 5, wherein The halogen is chlorine, bromine or fluorine.

7. The method according to claim 5, characterized in that, The haloalkyl is trifluoromethyl or difluoromethyl.

8. The method according to claim 5, characterized in that In step 1), the reaction is carried out in a solvent, and the solvent is absolute ethanol; the reaction temperature of the reaction is 25 °C.

9. The method according to claim 8, characterized in that, The absolute ethanol is in excess.

10. The method according to claim 5, characterized in that, In step 2), the reaction is carried out in a solvent, and the solvent is tetrahydrofuran; the reaction temperature of the reaction is 0 °C; the molar ratio of the pyrazole acid ester represented by formula II to the reducing agent in step 2) is (1:1)-(1:2).

11. The method according to claim 10, wherein The reducing agent is lithium aluminum hydride.

12. The method according to claim 5, wherein In step 3), the reaction is carried out in a solvent, and the solvent is dichloromethane; the reaction temperature of the reaction is 40 °C; the molar ratio of the compound represented by the general formula of formula III to the chlorinating reagent in step 3) is (1:1.2)-(1:2.5).

13. The method according to claim 5, wherein In step 4), the reaction is carried out in a solvent, and the solvent is dichloromethane; the reaction temperature of the reaction is room temperature; the molar ratio of 2-aminopyridine to the acyl chloride or acid anhydride in step 4) is (1:1)-(1:1.1).

14. The method according to claim 5, wherein In step 5), the reaction is carried out in a solvent, and the solvent is acetonitrile; the reaction temperature of the reaction is 80 °C; the base used in the reaction is potassium carbonate; the molar ratio of the compound represented by the general formula of formula V to the compound represented by the general formula of formula IV in step 5) is (1:1)-(1:1.1).

15. Use of the compound according to any one of claims 1-4, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition containing any one of them, in the preparation of a plant insecticide.

16. The application according to claim 15, characterized in that, The plant insecticide is an insecticide for killing homopterous pests and lepidopterous pests.

17. The application according to claim 16, wherein The homopterous pests are at least one of the following six families: Aphididae, Aleyrodidae, Delphacidae, Psyllidae, Cicadellidae and Coccidae; the lepidopterous pests are Noctuidae and Plutellidae.

18. A plant insecticidal drug or preparation, characterized in that, Its active ingredient is the compound according to any one of claims 1-4, or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition containing any one of them.

19. The plant insecticidal drug or preparation according to claim 18, characterized in that, The mass percentage content of the active ingredient in the plant insecticidal drug or preparation is 0.01%-99.99%.

20. The plant insecticidal drug or preparation according to claim 18, characterized in that, The plant insecticidal drug or preparation is a drug or preparation for killing homopterous pests and lepidopterous pests.

21. The pesticidal plant drug or preparation according to claim 20, characterized in that, The homopterous pests are at least one of the following six families: Aphididae, Aleyrodidae, Delphacidae, Psyllidae, Cicadellidae and Coccidae; the lepidopterous pests are Noctuidae and Plutellidae.

22. Use of the plant insecticidal drug or preparation according to claim 18 in controlling plant pests.

23. A method for controlling plant pests, characterized in that, Apply the plant insecticidal drug or preparation according to any one of claims 18-22 on plant leaves and / or fruits and / or seeds, and in the environment where the plant leaves and / or fruits and / or seeds are growing or expected to grow; the application concentration of the active ingredient of the plant insecticidal drug or preparation is 1-600 mg / L.

24. The method according to claim 23, wherein The application concentration of the active ingredient of the plant insecticidal drug or preparation is 3-50 mg / L.

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