A Dihydro Maleimide and Its Preparation Method and Application

Abstract

The present invention discloses a dihydro maleimide, its preparation method and application. The present invention extracts a CBT adduct of dihydro maleimide from peas, deduces the structural formula of dihydro maleimide, and artificially prepares this compound. Further research shows that this dihydro maleimide has strong insecticidal activity and antifeedant activity, and can be widely used as an active ingredient of plant-derived insecticides and antifeedants in the preparation of insecticides and antifeedants, solving the bottleneck problem of difficult large-scale preparation of plant-derived pesticides, and also providing new strategies and ideas for the green prevention and control of crop pests and the guarantee of agricultural product quality and safety.

Description

Technical Field

[0001] The present invention belongs to the technical field of pesticides. Specifically, the present invention relates to a dihydromaleimide, a preparation method thereof, and an application thereof. Background Art

[0002] With the increasing problems of agricultural product quality safety and environmental safety caused by pesticide residues and enhanced drug resistance, the research and development of new botanical pesticides with better environmental compatibility have been increasingly favored. Exploring and discovering bioactive natural products with novel structures from plant resources is the source and hot research field of the creation of new pesticides, and it is also one of the effective ways to develop green and environmentally friendly pesticides. Currently, a series of botanical pesticide products have been developed with pyrethrins, azadirachtin, rotenone, etc. as the active ingredients. However, there are only more than a dozen registered active ingredients of botanical pesticides at present. One of the more important reasons is that most plants containing insecticidal active ingredients are difficult to grow on a large scale, and it is difficult to obtain sufficient high-quality materials for separating active substances during the commercialization process; there are also some reasons that the artificial synthesis of insecticidal active ingredients from plants is relatively difficult. Therefore, it is of great significance to provide a botanical pesticide that can be extracted and artificially synthesized from plants grown on a large scale. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above-mentioned defects and deficiencies existing in the prior art and provide a dihydromaleimide.

[0004] The second purpose of the present invention is to provide a preparation method of the above-mentioned dihydromaleimide.

[0005] The third purpose of the present invention is to provide an application of the above-mentioned dihydromaleimide in pest control.

[0006] The fourth purpose of the present invention is to provide an application of the above-mentioned dihydromaleimide in the preparation of pesticides or antifeedants.

[0007] The above-mentioned purposes of the present invention are achieved by the following technical solutions:

[0008] The present invention provides a dihydromaleimide, and the dihydromaleimide is (R)-dihydromaleimide, and its structural formula is shown as the following formula (Ⅰ):

[0009] .

[0010] Pea ( Pisum sativumL.), is an annual climbing herbaceous plant of the genus Pisum in the legume family. It has a cultivation history of more than 6,000 years and is cultivated all over the world. It is the fourth largest legume crop globally; it is cultivated in most parts of China. Peas prefer a cool and humid climate, are light-loving, cold-tolerant, drought-tolerant, and have extremely strong adaptability to the soil. They can grow well in relatively barren land. Edible peas can be divided into grain peas and vegetable peas. Grain peas are harvested after the seeds mature, and the seeds are used as a food source; vegetable peas mainly eat fresh seeds, tender pods, or tender shoot tips, etc. The annual planting area of vegetable peas in China is about 20 million mu, and the cultivation area and output account for more than 50% of the world's total. In the present invention, a small molecule compound is isolated and identified from peas. This small molecule compound is an amide small molecule compound produced after the decomposition of glycoside compounds in peas and is identified as (R)-dihydro maleimide. The structural formula is as shown in the above formula (Ⅰ).

[0011] Based on the CBT adduct structural formula of dihydro maleimide, the present invention infers the structural formula of dihydro maleimide. When the structural formula of dihydro maleimide is known, those skilled in the art can use maleimide, sodium borohydride, and cerium chloride to synthesize this amide compound by the Luche reduction method. By measuring the circular dichroism spectra of the CBT adduct of dihydro maleimide obtained from peas and the CBT adduct of the enantiomer of synthetic dihydro maleimide with a circular dichroism spectrometer, the results show that the spectrum of (R)-configured dihydro maleimide matches well with that of dihydro maleimide in peas.

[0012] Specifically, the present invention also provides a preparation method of dihydro maleimide, including the following steps:

[0013] S1. Mix and dissolve maleimide and cerium chloride heptahydrate, and then add a sodium borohydride solution for a reduction reaction;

[0014] S2. Mix the solution in step S1 with silica gel powder and dry it into a powder;

[0015] S3. Separate and purify by column chromatography to obtain dihydro maleimide, and then separate its enantiomer to obtain the R-configured dihydro maleimide shown in formula (Ⅰ).

[0016] Furthermore, in step S1, the mass ratio of maleimide, cerium chloride heptahydrate, and sodium borohydride is 5:18 - 20:1.8 - 2.

[0017] Preferably, in step S1, the mass ratio of maleimide, cerium chloride heptahydrate, and sodium borohydride is 5:19.185:1.9.

[0018] Furthermore, the reduction reaction in step S1 is carried out at 0°C - 5°C for more than 1.5 h.

[0019] Furthermore, the eluent used in the column chromatography in step S3 is dichloromethane / methanol = 9:1.

[0020] Furthermore, the enantiomer separation in step S3 is carried out by supercritical fluid chromatography.

[0021] Furthermore, the chromatographic column used in the supercritical fluid chromatography is ChiralPak IH (40 mm×250 mm, 10 μm), the flow rate is 120 mL / min, and the supercritical CO 2 solution with 25% methanol is used as the mobile phase.

[0022] Therefore, the dihydromaleimide involved in the present invention can be separated from pea plants or synthesized artificially, and the synthesis route is simple and can be mass-produced, laying a foundation for the development and application of dihydromaleimide.

[0023] The present invention further studies and finds that the dihydromaleimide prepared by the present invention has extremely strong water solubility. After dissolving it in water and soaking the leaves, it has strong insecticidal activity against Lepidoptera pests represented by Spodoptera frugiperda and underground pests (Coleoptera) represented by Holotrichia parallela, and has strong antifeedant activity against Spodoptera frugiperda; but has weak insecticidal activity against Hemiptera pests represented by Riptortus pedestris.

[0024] Therefore, the present invention provides the application of the above dihydromaleimide in pest control.

[0025] Furthermore, the method of pest control is insecticidal or antifeedant.

[0026] Furthermore, the pests are Lepidoptera, Coleoptera or Hemiptera pests.

[0027] Furthermore, the pests are Spodoptera frugiperda, Holotrichia parallela or Riptortus pedestris. The LC 50 of dihydromaleimide against Spodoptera frugiperda at 24 h is 3.417 mg / mL, and the LC 50 at 48 h is 2.600 mg / mL; the LC 50 of dihydromaleimide against Holotrichia parallela at 24 h is 1.788 mg / g, and the LC 50 at 48 h is 1.721 mg / g; the LC 50 of dihydromaleimide against Riptortus pedestris at 72 h is 27.030 mg / mL.

[0028] The present invention also provides the application of the above dihydromaleimide in the preparation of insecticides or antifeedants.

[0029] Furthermore, the dosage forms of the insecticides or antifeedants are emulsifiable concentrates, suspensions, suspoemulsions, microemulsions, emulsifiable water concentrates, wettable powders, soluble powders, granules or capsules.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention discloses a dihydro maleimide and its preparation method and application. The present invention extracts a CBT adduct of dihydro maleimide from peas, speculates the structural formula of dihydro maleimide, and artificially prepares the compound. Further research shows that the dihydro maleimide has strong insecticidal activity and antifeedant activity, and can be widely used as an active ingredient of plant-derived insecticides and antifeedants in the preparation of insecticides and antifeedants, solving the bottleneck problem of difficult large-scale preparation of plant-derived pesticides, and also providing new strategies and ideas for the green prevention and control of crop pests and the guarantee of agricultural product quality and safety. Description of the Drawings

[0032] Figure 1 For the structural identification of dihydro maleimide and its glycosides in snow peas. Among them, Figure 1 A and B in are the high-resolution mass spectrometry and isotope distribution data of Compound 1 and Compound 2; C is the structural formula of Compound 1 and Compound 2; D shows that Compound 2 is the glucoside form of Compound 1 by single crystal X-ray diffraction analysis; E is the structural formula of (R)-dihydro maleimide (DHM) and (R)-dihydro maleimide β-D-glucoside (DHMG).

[0033] Figure 2 For the insecticidal activity of dihydro maleimide against Spodoptera frugiperda.

[0034] Figure 3 For the insecticidal activity of dihydro maleimide against white grubs.

[0035] Figure 4 For the insecticidal activity of dihydro maleimide against Riptortus pedestris.

[0036] Figure 5 For the antifeedant activity of dihydro maleimide against Spodoptera frugiperda.

[0037] Figure 6 For the absolute gastric toxicity dose of dihydro maleimide against Spodoptera frugiperda. Detailed Embodiments

[0038] The following further illustrates the present invention in conjunction with the accompanying drawings of the specification and specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the technical field.

[0039] Unless otherwise specified, the reagents and materials used in the following examples are all commercially available.

[0040] Example 1 Identification of the Structures of Dihydro Maleimide and Its Glycosides Derived from Peas

[0041] I. Experimental Methods

[0042] (1) Take 100 g of fresh snow peas (tender pod peas), wash them slightly, put them into a juicer, and add an appropriate amount of deionized water to finally obtain 300 mL of solution;

[0043] (2) After shaking for 5 h, place it in a water bath at 80 °C for 0.5 h;

[0044] (3) Filter out the juice and concentrate it to 15 mL using a rotary evaporator;

[0045] (4) Carry out an adduct reaction with 4-chlorothiophenol (CBT, CAS No.: 106 - 54 - 7): 15 mL of concentrated snow pea liquid + 20 mL of methanol (analytical grade) + 2 mL of DMSO solution of 4-chlorothiophenol (0.2 g / mL) + 4 mL of phosphate buffer solution (pH = 7.3);

[0046] (5) After reacting for 12 h, filter the mixture using an organic filter head (0.45 μm);

[0047] (6) Use a preparative liquid chromatograph to collect the CBT adduct of maleimide and its glycoside. The collection parameters of the liquid chromatography are as follows: The mobile phase is deionized water (phase A) and methanol (phase B). The specific gradient is shown in Table 1. The signal wavelength of the ultraviolet detector is 254 nm. The retention times of the CBT adduct of maleimide and its glycoside are 38 min and 36 min respectively. Collect the fractions;

[0048] Table 1 Collection Parameters of Liquid Chromatography

[0049]

[0050] (7) Concentrate the collected liquid using a rotary evaporator, and then obtain a dry solid using a freeze dryer;

[0051] (8) Identify the accurate structures of the CBT adduct of maleimide and its glycoside through high-resolution MS / MS spectral analysis, combined with nuclear magnetic resonance technology and single-crystal X-ray diffraction technology, and then infer the chemical formula and structure of maleimide extracted by this method.

[0052] II. Experimental Results

[0053] In the CBT reaction products of the methanol extract of snow peas, two high-abundance molecular ions with m / z 244.0195 (Compound 1) with retention times of 3.10 and 3.22 min and m / z 406.0729 (Compound 2) with a retention time of 2.72 min were detected by high-resolution mass spectrometryFigure 1 A in Figure 1 and B in 0-100 H 0-100 O 0-20 N 0-10 ClS + With the elemental composition of, mass accuracy <2 ppm, the predicted molecular formulas of Compounds 1 and 2 are C 10 H 11 O 2 NClS + (0.79 ppm) and C 16 H 21 O 7 NClS + (1.87 ppm) ( Figure 1 A in Figure 1 and B in 1 1H NMR (CD 3 OD, 600 MHz) spectrum chemical shifts δ (ppm) are as follows: 7.43 (2H, m), 7.36 (2H, m), 5.05 (1H, d, J = 0.78 Hz), 3.75 (1H, ddd, J = 8.15, 2.51, 1.04 Hz), 3.05 (1H, dd, J = 17.9, 8.1 Hz), 2.1 (1H, dd, J = 17.9, 2.6 Hz). 13 13C NMR (CD 3 OD, 150 MHz) spectrum δ (ppm) are as follows: 178.2, 133.4, 130.4, 85.6, 50.9, 36.4. Therefore, the structure of Compound 1 is determined to be (5R)-4-((4-chlorophenyl)thio)-5-hydroxypyrrolidin-2-one ( Figure 1 C in 1 1H NMR (CD 3The (¹H, NMR, 600 MHz) spectrum δ (ppm) is as follows: 7.48 (2H, m), 7.39 (2H, m), 5.11 (1H, s), 4.21 (1H, d, J = 7.8 Hz), 4.06 (1H, dd, J = 8.2, 1.5 Hz), 3.86 (1H, dd, J = 12.0, 1.8 Hz), 3.64 (1H, dd, J = 12.0, 6.0 Hz), 3.33 (1H, m), 3.11 (1H, t, J = 9.0 Hz), 3.25 (1H, t, J = 7.8 Hz), 3.21 (1H, t, J = 7.2 Hz), 3.18 (1H, dd, J = 9.8, 2.3 Hz), 3.11 (1H, dd, J = 18.1, 8.4 Hz), 2.1 (1H, dd, J = 18.1, 2.0 Hz). Further single-crystal X-ray diffraction analysis showed that Compound 2 is the glucoside form of Compound 1 ( Figure 1 D in), so the structure of Compound 2 was unambiguously identified as (5R)-4-((4-chlorophenyl)thio)-5-(((2R,3R,4R,5R,6S)-3,4,5-trihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yl)oxy)pyrrolidin-2-one ( Figure 1 C in).

[0054] Continue to identify the structure of the original thiol-reactive compounds from the pea extract. Based on the structure of the CBT adducts, it was deduced that the original thiol-reactive compounds are α,β-unsaturated carbonyl compounds, which react with the thiol groups in CBT through Michael addition reactions. Therefore, the structures of the original thiol-reactive compounds were speculated to be (R)-dihydromaleimide (DHM) and (R)-dihydromaleimide β-D-glucoside (DHMG) ( Figure 1 E in). Guided by high-resolution mass spectrometry, the water-soluble sub-fraction in the methanol extract of peas was separated using preparative liquid chromatography, and a purified product with a quasi-molecular ion of m / z 262.0921 was successfully obtained, which is the same as the m / z of the DHMG proton adduct. In addition, 1 ¹H NMR (D 2The \(^1H\) NMR (\(D_2O\), 600 MHz) spectrum shows \(\delta\) (ppm): 7.24 (1H, dd, \(J = 5.8, 1.5\) Hz), 6.21 (1H, d, \(J = 5.8\) Hz), 5.87 (1H, s), 4.62 (1H, d, \(J = 7.9\) Hz), 3.93 (1H, dd, \(J = 12.5, 1.9\) Hz), 3.73 (1H, dd, \(J = 12.5, 5.9\) Hz), 3.51 (1H, t, \(J = 9.2\) Hz), 3.46 (1H, ddd, \(J = 9.9, 5.8, 1.9\) Hz), 3.40 (1H, t, \(J = 9.4\) Hz), 3.32 (1H, t, \(J = 8.7\) Hz); 13 \(^{13}\)C NMR (\(CD\) 3 \(OD\), 150 MHz) spectrum shows \(\delta\) (ppm): 174.9, 148.4, 128.8, 103.3, 88.3, 78.4, 77.9, 74.8, 71.4, 62.7, confirming that the structure of the compound is DHMG. An ion with \(m / z\) 100.0392 was also detected in the water-soluble subfraction, which is the same as the \(m / z\) of the DHM proton adduct. Due to the presence of impurities, the structure of the compound could not be confirmed by NMR. Therefore, DHM was subsequently synthesized by the Luche reduction method (Example 2), and its retention time and MS / MS spectrum were consistent with those of the ion with \(m / z\) 100.0392 in the methanol extract of snow pea, Figure 1 confirming the presence of DHM in the snow pea extract. The 1 \(^1H\) NMR (\(D\) 2 \(_2O\), 600 MHz) spectrum shows \(\delta\) (ppm): 7.15 (1H, d, \(J = 5.8\) Hz), 6.17 (1H, d, \(J = 5.8\) Hz), 5.76 (1H, s); 13 \(^{13}\)C NMR (\(CD\) 3 \(OD\), 150 MHz) spectrum shows \(\delta\) (ppm): 174.5, 150.7, 128.2, 82.0.

[0055] Example 2 Synthesis of Dihydromaleimide

[0056] I. Synthesis method (Luche reduction method)

[0057] (1) Cerium(III) chloride heptahydrate (19.185 g) was added to a methanol solution (50 mL, AR grade) of maleimide (5 g), and stirred well to dissolve it;

[0058] (2) Slowly pour sodium borohydride (1.9 g) into the mixed solution in (1) in an ice-water bath, and stir for more than 1.5 h;

[0059] (3) Take out the stir bar, add 30 g of silica gel powder, dropwise add an appropriate amount of methanol (AR grade) to fully mix the sample and silica gel powder, and then rotary evaporate to make the mixture into a dry powder;

[0060] (4) Use column chromatography (the chromatography column is self-packed 300-mesh silica gel powder, about 1 / 3 of the height of the chromatography column, eluent: dichloromethane / methanol, 9:1) to separate and collect the synthesized dihydromaleimide (stop collecting when the yellow liquid in the silica gel column is about to rush out);

[0061] (5) Concentrate the collected liquid and freeze-dry it into a solid powder;

[0062] (6) Use supercritical fluid chromatography to separate the enantiomers of the product to obtain two enantiomers with different configurations. The chromatography column is ChiralPak IH (40 mm×250 mm, 10 μm), the flow rate is 120 mL / min, and the supercritical CO 2 solution with 25% methanol is used as the mobile phase.

[0063] II. Synthesis Results

[0064] In order to confirm which enantiomer is consistent with dihydromaleimide in peas, CBT adducts of the two enantiomer compounds were prepared respectively, and the circular dichroism spectra of the CBT adducts of dihydromaleimide in peas and the enantiomer adducts were measured using a circular dichroism spectrometer. The enantiomer with a good spectral match is the (R) configuration consistent with dihydromaleimide in peas.

[0065] Example 3 Determination of Insecticidal Activity of Dihydromaleimide against Spodoptera frugiperda

[0066] I. Experimental Method

[0067] According to the "Guidelines for Indoor Bioassay of Pesticides - Part 14: Leaf-dipping Method for Insecticides", the stomach toxicity of dihydromaleimide was tested using Spodoptera frugiperda ( Spodoptera frugiperda ) as the test pest.

[0068] In this example, the insecticidal activity of the (R)-configuration dihydromaleimide prepared in Example 2 against Spodoptera frugiperda was experimented as follows:

[0069] Dissolve dihydro maleimide in deionized water to obtain aqueous solutions (containing 0.1% Tween 80) with concentrations of 12 mg / mL, 8 mg / mL, 5 mg / mL, 2.5 mg / mL, and 1.25 mg / mL; immerse corn round leaves with a diameter of about 1 cm in the medicinal liquid of each concentration for 0.5 h, air-dry them slightly at room temperature, and place 1 healthy 4th-instar Spodoptera frugiperda larva that has been starved for 24 h into each sample. There are 3 replicates in each group, and 15 Spodoptera frugiperda larvae in each replicate; at the same time, set up a blank control without dihydro maleimide (containing 0.1% Tween 80) and a reference medicament control (2 mL of 0.5% azadirachtin emulsifiable concentrate + 8 mL of deionized water); count the mortality of Spodoptera frugiperda at 24 h and 48 h.

[0070] II. Experimental Results

[0071] The results are as Figure 2 shown. After the Spodoptera frugiperda larvae ate the corn leaves soaked in the dihydro maleimide medicinal liquid, the mortality rate showed a trend of increasing with the increase of concentration. The LC 50 of dihydro maleimide against Spodoptera frugiperda at 24 h was 3.417 mg / mL, and the LC 50 at 48 h was 2.600 mg / mL.

[0072] Example 4 Determination of Insecticidal Activity of Dihydro Maleimide against White Grubs

[0073] I. Experimental Method

[0074] According to the "Pesticide Bioassay Guidelines for Laboratory Tests - Insecticides - Part 10: Method of Mixing Drugs in Artificial Diet", the gastric toxicity activity of dihydro maleimide was tested using the larvae of Potosia brevitarsis Lewis (white grubs) ( Protaetia brevitarsis ).

[0075] In this example, the insecticidal activity of the (R)-configuration dihydro maleimide prepared in Example 2 against white grubs was experimentally tested, and the steps are as follows:

[0076] Take 10 mL of deionized water, dissolve it and mix it evenly with 15 g of fermented cow dung soil to prepare fermented cow dung soil with concentrations of 5 mg / g, 3.34 mg / g, 2.5 mg / g, 1.67 mg / g, 1.25 mg / g, and 0.625 mg / g, and air-dry it appropriately; put 15 healthy 3rd-instar white grubs into the soil of each treatment concentration, with 3 replicates in each group; at the same time, set up a blank control without dihydro maleimide and a reference medicament control (using 0.5% azadirachtin emulsifiable concentrate to make the concentration of azadirachtin in the fermented cow dung soil 1.67 mg / g). Count the mortality of white grubs at 24 h and 48 h.

[0077] II. Experimental Results

[0078] The results are as follows Figure 3 shown that the insecticidal activity of this amide compound against white grubs is comparable to that of azadirachtin emulsifiable concentrate. The LC 50 of maleic diimide against white grubs at 24 h is 1.788 mg / g, and the LC 50 at 48 h is 1.721 mg / g.

[0079] Example 5 Determination of Insecticidal Activity of Maleic Diimide Against Riptortus pedestris

[0080] I. Experimental Method

[0081] According to the "Guidelines for Indoor Bioassay of Pesticides - Part 14: Leaf-dipping Method for Insecticides", with Riptortus pedestris ( Riptortus pedestris ) as the test pest, the stomach toxicity activity of maleic diimide was tested.

[0082] In this example, the insecticidal activity of the (R)-configuration maleic diimide prepared in Example 2 against Riptortus pedestris was experimented as follows:

[0083] Take this amide compound and prepare aqueous solutions of 20 mg / mL, 10 mg / mL, 5 mg / mL, 2.5 mg / mL, and 1.25 mg / mL (containing 0.1% Tween 80) with deionized water; 3 fresh 7-cm-long string beans are soaked in the liquid medicine for about 12 h, then properly air-dried, and fed into the rearing boxes of 10 healthy 3rd-instar Riptortus pedestris. There are 4 replicates for each concentration; at the same time, a blank control without maleic diimide (containing 0.1% Tween 80) and a reference medicament control group (7.5 mL of 0.5% azadirachtin emulsifiable concentrate + 22.5 mL of deionized water) are set; the mortality of Riptortus pedestris after 72 h is counted.

[0084] II. Experimental Results

[0085] The results are as follows Figure 4 shown that after Riptortus pedestris fed on string beans soaked in the liquid medicine of maleic diimide at an extremely high concentration (20 mg / mL), the mortality rate did not exceed 50%. Compared with the insecticidal activity against the previous two pests, it was significantly lower. The LC 50 at 72 h was 27.030 mg / mL.

[0086] Both Spodoptera frugiperda larvae and white grubs belong to chewing mouthparts. When feeding on food, they can eat maleic diimide into their bodies without selectivity. However, Riptortus pedestris sucks the internal juice of string beans, while most of the maleic diimide remains on the epidermis of string beans and is difficult to penetrate into the internal juice of string beans, which may therefore show lower insecticidal activity against Riptortus pedestris.

[0087] Example 6 Determination of Antifeedant Activity of Dihydro Maleimide against Spodoptera frugiperda

[0088] I. Experimental Method

[0089] According to the "Guidelines for Indoor Bioassay of Pesticides - Part 14: Leaf-dipping Method for Insecticides", using Spodoptera frugiperda ( Spodoptera frugiperda ) as the test pest, the antifeedant activity of dihydro maleimide was tested

[0090] In this example, the antifeedant activity of the (R)-configuration dihydro maleimide prepared in Example 2 against Spodoptera frugiperda was experimented, and the steps are as follows:

[0091] Take this amide compound and obtain aqueous solutions of 3 mg / mL, 1.5 mg / mL, 0.75 mg / mL, 0.375 mg / mL, and 0.1875 mg / mL (containing 0.1% Tween 80) with deionized water; soak corn circular leaves with a direct area of about 1.5 cm for 0.5 h, slightly air-dry at room temperature, and place them into a feeding cup containing wet absorbent cotton balls; then put in 1 healthy 4th-instar Spodoptera frugiperda that has been starved for 6 h, with 5 replicates in each group; at the same time, set a blank control without dihydro maleimide and a reference agent control (1 mL of 0.5% azadirachtin emulsifiable concentrate + 9 mL of deionized water (containing 0.1% Tween 80), so that the azadirachtin concentration is 0.5 mg / mL); count and photograph the area of corn leaves of the surviving individuals after 24 h, and calculate the antifeedant rate.

[0092] II. Experimental Results

[0093] The results are as Figure 5 shown. At low concentrations (the concentration of dihydro maleimide liquid medicine is 0.1875 mg / mL, 0.375 mg / mL, 0.75 mg / mL), there is no obvious antifeedant activity, but after the concentration exceeds 1.5 mg / mL, it shows a phenomenon of increasing with the increase of concentration, and the median antifeedant concentration AFC 50 is about 1.903 mg / mL.

[0094] Example 7 Determination of the Absolute Gastric Toxic Dose of Dihydro Maleimide against Spodoptera frugiperda

[0095] I. Experimental Method

[0096] According to the "Standard Operating Procedure for Pesticide Bioactivity Testing - Insecticide Volume", using Spodoptera frugiperda ( Spodoptera frugiperda ) as the test pest, the absolute gastric toxic dose value of dihydro maleimide was tested.

[0097] In this example, experiments were conducted on the determination of the absolute gastric toxicity dose of the (R)-configured dihydro maleimide prepared in Example 2 against Spodoptera frugiperda, and the steps were as follows: An aqueous solution of this amide compound with concentrations of 32 mg / mL, 16 mg / mL, 8 mg / mL, 4 mg / mL, and 2 mg / mL was prepared; 1 μL of the liquid medicine was dropped on a small piece of feed, and then fed to a 5th-instar Spodoptera frugiperda that had been starved for 12 h. There were 3 replicates for each concentration, and 20 insects for each replicate. After observing that the feed was eaten up, fresh feed without the dropped liquid medicine was supplemented, and a blank control group was set up at the same time; The mortality rate of each treatment group was statistically counted every day.

[0098] II. Experimental Results

[0099] The results are as Figure 6 shown. When Spodoptera frugiperda larvae fed on the artificial feed containing 32 μg of dihydro maleimide, the mortality rate was close to 100% within 1 day, and then the mortality rate remained almost unchanged at other doses. The LD 50 value was approximately 19.058 μg.

Claims

1. Use of dihydromaleimide in the preparation of pest insecticides or antifeedants, characterized in that: The pest is a Lepidoptera, Coleoptera or Hemiptera pest; the structural formula of the dihydromaleimide is shown in the following formula (I): 。 2. The application according to claim 1, characterized in that: The dosage form of the insecticide or antifeedant is emulsifiable concentrate, suspension, suspoemulsion, microemulsion, aqueous emulsion, wettable powder, soluble powder, granule or capsule.

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