Dihydromaleimide as well as preparation method and application thereof

Abstract

The invention discloses dihydromaleimide and a preparation method and application thereof, a CBT adduct of the dihydromaleimide is extracted from peas, the structural formula of the dihydromaleimide is speculated, and the compound is artificially prepared. Further research shows that the dihydromaleimide has relatively strong insecticidal activity and antifeedant activity, can be used as an active ingredient of a botanical pesticide and an antifeedant to be widely applied to preparation of the pesticide and the antifeedant, solves the bottleneck problem that the botanical pesticide is difficult to prepare in a large scale, and has a wide application prospect. And new strategies and ideas are provided for green prevention and control of crop insect pests and quality safety guarantee of agricultural products.

Description

Technical Field

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

[0002] With the increase of agricultural product quality safety and environmental safety caused by pesticide residues and increased resistance, the research and development of new botanical insecticides with good environmental compatibility has become more and more popular. Mining and discovering biologically active natural products with novel structures from plant resources is the source and hot research field of new pesticide creation, and it is also one of the effective ways to develop green and environmentally friendly pesticides. At present, a series of botanical insecticide products have been developed with pyrethrin, azadirachtin, rotenone and other active ingredients. However, there are only more than ten kinds of registered botanical insecticide active ingredients. 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 commercialization; another reason is that it is difficult to artificially synthesize plant-derived insecticidal active ingredients. Therefore, it is of great significance to provide a botanical insecticide 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 defects and shortcomings in the prior art and provide a dihydromaleimide.

[0004] The second object of the present invention is to provide a method for preparing the above dihydromaleimide.

[0005] The third object of the present invention is to provide the use of the above dihydromaleimide in controlling pests.

[0006] The fourth object of the present invention is to provide the use of the above dihydromaleimide in the preparation of insecticides or antifeedants.

[0007] The above-mentioned object of the present invention is achieved through the following technical solutions: The present invention provides a dihydromaleimide, wherein the dihydromaleimide is (R)-dihydromaleimide, and its structural formula is shown in the following formula (I): .

[0008] pea( Pisum sativumL.), is an annual climbing herb of the genus pea in the leguminous family. It has a cultivation history of more than 6,000 years and is cultivated all over the world. It is the fourth largest soybean crop in the world; it is cultivated in most parts of China. Peas prefer cool and humid climates, are light-loving, cold-resistant, and drought-resistant. They have strong adaptability to soil and can grow well in relatively poor 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 are mainly eaten as fresh seeds, young pods or young stem tips. The annual planting area of ​​vegetable peas in my country is about 20 million mu, and the cultivated area and output account for more than 50% of the world's total. The present invention separates and identifies a small molecule compound from peas. The small molecule compound is an amide small molecule compound produced by the decomposition of glycoside compounds in peas, which is identified as (R)-dihydromaleimide, and the structural formula is shown in the above formula (I).

[0009] The present invention infers the structural formula of dihydromaleimide based on the structural formula of the CBT adduct of dihydromaleimide. When the structural formula of dihydromaleimide is known, those skilled in the art can use maleimide, sodium borohydride and cerium chloride to perform Luche reduction method to synthesize the amide compound. The circular dichroism spectra of the CBT adduct of dihydromaleimide obtained from peas and the CBT adduct of the artificially synthesized dihydromaleimide enantiomer are measured by circular dichroism spectrometer. The results show that the (R) configuration of dihydromaleimide matches well with the spectrum of dihydromaleimide in peas.

[0010] Specifically, the present invention also provides a method for preparing dihydromaleimide, comprising the following steps: S1. Dissolving maleimide and cerium chloride heptahydrate, and then adding sodium borohydride solution for reduction reaction; S2. The solution in step S1 is mixed with silica gel powder and dried into a powder; S3. Separate and purify by column chromatography to obtain dihydromaleimide, and then separate its enantiomers to obtain R-configuration dihydromaleimide shown in formula (I).

[0011] Furthermore, in step S1, the mass ratio of maleimide, cerium chloride heptahydrate and sodium borohydride is 5:18-20:1.8-2.

[0012] Preferably, in step S1, the mass ratio of maleimide, cerium chloride heptahydrate and sodium borohydride is 5:19.185:1.9.

[0013] Furthermore, the reduction reaction in step S1 is carried out at 0°C to 5°C for more than 1.5 h.

[0014] Furthermore, the eluent used in the column chromatography method in step S3 is dichloromethane / methanol=9:1.

[0015] Furthermore, the enantiomer separation in step S3 is carried out by supercritical fluid chromatography.

[0016] Furthermore, the supercritical fluid chromatography method used a ChiralPak IH column (40 mm×250 mm, 10 μm) with a flow rate of 120 mL / min and a supercritical CO 2 The solution is the mobile phase.

[0017] Therefore, the dihydromaleimide of the present invention can be separated from pea plants or artificially synthesized, and the synthesis route is simple and can be produced in large quantities, thus laying a foundation for the development and application of dihydromaleimide.

[0018] Further research of the present invention found that the dihydromaleimide prepared by the present invention is extremely water-soluble. After dissolving it in water and soaking leaves, it has strong insecticidal activity against Lepidoptera pests represented by the fall armyworm and underground pests (Coleoptera) represented by white grubs, and has strong antifeedant activity against the fall armyworm; but has weak insecticidal activity against Hemiptera represented by the bee-edge bug.

[0019] Therefore, the present invention provides the use of the dihydromaleimide in controlling pests.

[0020] Furthermore, the method of controlling pests is killing insects or refusing to feed.

[0021] Furthermore, the pests are pests of the order Lepidoptera, Coleoptera or Hemiptera.

[0022] Furthermore, the pest is fall armyworm, white grub or bee stink bug. The 24 h LC of dihydromaleimide against fall armyworm is 50 The LC value of 3.417 mg / mL at 48 h 50 2.600 mg / mL; 24 h LC value for grubs 50 LC value of 1.788 mg / g at 48 h 50 The LC value of the stink bug for 72 h is 1.721 mg / g. 50 It is 27.030 mg / mL.

[0023] The present invention also provides the use of the dihydromaleimide in preparing insecticides or antifeedants.

[0024] Furthermore, the dosage form of the insecticide or antifeedant is emulsifiable concentrate, suspension concentrate, suspoemulsion, microemulsion, aqueous emulsion, wettable powder, soluble powder, granule or capsule.

[0025] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a dihydromaleimide and a preparation method and application thereof. The present invention extracts a CBT adduct of dihydromaleimide from peas, infers the structural formula of dihydromaleimide, and artificially prepares the compound. Further studies have shown that the dihydromaleimide has strong insecticidal activity and antifeedant activity, and can be widely used in the preparation of insecticides and antifeedants as an active ingredient of botanical insecticides and antifeedants, solving the bottleneck problem of the difficulty in mass preparation of botanical pesticides, and also providing new strategies and ideas for green prevention and control of crop pests and quality and safety assurance of agricultural products. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The structural identification of dihydromaleimide and its glycosides in snow peas. Figure 1 A and B are the high-resolution mass spectra and isotope distribution data of compounds 1 and 2; C is the structural formulas of compounds 1 and 2; D is the single crystal X-ray diffraction analysis showing that compound 2 is the glucoside form of compound 1; E is the structural formula of (R)-dihydromaleimide (DHM) and (R)-dihydromaleimide β-D-glucoside (DHMG).

[0027] Figure 2 The insecticidal activity of dihydromaleimide against fall armyworm.

[0028] Figure 3 The insecticidal activity of dihydromaleimide against grubs.

[0029] Figure 4 The insecticidal activity of dihydromaleimide against the bee-margin stink bug.

[0030] Figure 5 The antifeedant activity of dihydromaleimide against fall armyworm.

[0031] Figure 6 is the absolute dose of dihydromaleimide as a stomach toxicant to fall armyworm. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with the accompanying drawings and specific examples, but the examples 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 art.

[0033] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0034] Example 1 Identification of the structures of dihydromaleimide and its glycosides from pea 1. Experimental Methods (1) Take 100 g of fresh snow peas (tender peas), wash them clean, put them into a juicer, add appropriate amount of deionized water, and finally obtain 300 mL of solution; (2) After shaking for 5 h, place in a water bath at 80 °C for 0.5 h; (3) Filter the juice and concentrate it to 15 mL using a rotary evaporator; (4) Addition reaction with 4-chlorobenzenethiol (CBT, CAS No.: 106-54-7): 15 mL of snow pea concentrate + 20 mL of methanol (analytical grade) + 2 mL of 4-chlorobenzenethiol (0.2 g / mL) DMSO solution + 4 mL of phosphate buffer (pH = 7.3) solution; (5) After 12 h of reaction, filter the mixture using an organic filter (0.45 μm); (6) Using a preparative liquid chromatograph to collect the CBT adduct of dihydromaleimide 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 UV detector signal wavelength is 254 nm, the retention times of the CBT adduct of dihydromaleimide and its glycoside are 38 min and 36 min, respectively, and the fractions are collected; Table 1 Collection parameters of liquid chromatography

[0035] (7) Concentrating the collected liquid using a rotary evaporator and then using a freeze dryer to obtain a dry solid; (8) The exact structures of the CBT adduct of dihydromaleimide and its glycoside were identified by high-resolution MS / MS spectral analysis combined with nuclear magnetic resonance technology and single crystal X-ray diffraction technology, and the chemical formula and structure of dihydromaleimide extracted by this method were deduced.

[0036] 2. Experimental Results In the CBT reaction product of the methanol extract of snow pea, two high-abundance molecular ions, m / z 244.0195 (compound 1) with retention times of 3.10 and 3.22 min and m / z 406.0729 (compound 2) with retention time of 2.72 min, were detected by high-resolution mass spectrometry ( Figure 1 A and Figure 1 B in Figure 1). Based on the isotope distribution data, both compounds are predicted to contain one Cl atom and one S atom. Then, by using C 0-100 H 0-100 O 0-20 N 0-10 C1S +The elemental composition of the compound 1 and 2 was predicted to be C 10 H 11 O 2 NClS + (0.79 ppm) and C 16 H 21 O 7 NClS + (1.87ppm) Figure 1 A and Figure 1 Then, the two compounds were separated by preparative liquid chromatography and characterized by nuclear magnetic resonance spectroscopy. 1 H NMR (CD 3 OD, 600 MHz) spectrum chemical shift δ (ppm) is 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 C 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 was determined to be (5R)-4-((4-chlorophenyl)thio)-5-hydroxypyrrolidin-2-one ( Figure 1 C in the above). 1 H NMR (CD 3OD, 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 the figure), 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.

[0037] The structures of the original thiol-reactive compounds from the snow pea extract were further identified. Based on the structure of the CBT adduct, it was inferred that the original thiol-reactive compounds were α, β-unsaturated carbonyl compounds, which reacted with the sulfhydryl groups in CBT through the Michael addition reaction. Therefore, the structures of the original thiol-reactive compounds were inferred to be (R)-dihydromaleimide (DHM) and (R)-dihydromaleimide β-D-glucoside (DHMG) ( Figure 1 E in the figure). The water-soluble subfractions in the methanol extract of snow peas were separated by preparative liquid chromatography guided by high-resolution mass spectrometry, 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 H NMR (D 2O, 600 MHz) spectrum δ (ppm) showed 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 C NMR (CD 3 OD, 150 MHz) spectrum δ (ppm) showed 174.9, 148.4, 128.8, 103.3, 88.3,78.4, 77.9, 74.8, 71.4, 62.7, confirming that the compound structure was DHMG. An ion of m / z 100.0392 was also detected in the water-soluble subfraction, which was 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 the retention time and MS / MS spectrum of the m / z 100.0392 ion in the snow pea methanol extract. Figure 1 The results showed that DHM existed in snow pea extract. 1 H NMR (D 2 O, 600 MHz) spectrum δ (ppm) showed 7.15 (1H, d, J = 5.8 Hz), 6.17 (1H, d, J = 5.8 Hz), 5.76 (1H, s); 13 C NMR (CD 3 OD, 150 MHz) spectrum δ (ppm) showed 174.5, 150.7, 128.2, 82.0.

[0038] Example 2 Synthesis of dihydromaleimide 1. Synthesis method (Luche reduction method) (1) Add cerium chloride heptahydrate (19.185 g) to a methanol solution (50 mL, AR grade) of maleimide (5 g) and stir thoroughly to dissolve. (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; (3) Remove the stirring bar, add 30 g of silica gel powder, and drop an appropriate amount of methanol (AR grade) to mix the sample and silica gel powder thoroughly. Then spin dry to make the mixture into dry powder; (4) Use column chromatography (the chromatography column is self-filled with 300 mesh silica gel powder, which is about 1 / 3 of the height of the chromatography column, and the eluent is 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); (5) Concentrating the collected liquid and freeze-drying it into a solid powder; (6) Supercritical fluid chromatography was used to separate the product enantiomers to obtain two enantiomers with different configurations. The chromatographic column was ChiralPak IH (40 mm × 250 mm, 10 μm), the flow rate was 120 mL / min, and the supercritical CO was used with 25% methanol. 2 The solution is the mobile phase.

[0039] 2. Synthesis Results In order to confirm which enantiomer is consistent with dihydromaleimide in peas, CBT adducts of two enantiomeric compounds were prepared respectively, and the circular dichroism spectra of the CBT adduct and enantiomeric adduct of dihydromaleimide in peas were obtained using a circular dichroism spectrometer. The enantiomer with a good spectrum match is the (R) configuration consistent with dihydromaleimide in peas.

[0040] Example 3 Determination of the insecticidal activity of dihydromaleimide against fall armyworm 1. Experimental Methods According to the "Guidelines for Indoor Bioassay Tests for Pesticides - Part 14: Leaf Dip Method", the fall armyworm ( Spodoptera frugiperda ) were used as test pests, and the stomach poison activity of dihydromaleimide was tested.

[0041] In this example, the insecticidal activity of the (R)-configuration dihydromaleimide prepared in Example 2 against fall armyworm was tested in the following steps: Dihydromaleimide was dissolved in deionized water to obtain aqueous solutions of 12 mg / mL, 8 mg / mL, 5 mg / mL, 2.5 mg / mL, and 1.25 mg / mL (containing 0.1% Tween 80). Corn round leaves with a diameter of about 1 cm were immersed in the solution of each concentration for 0.5 h, slightly dried in the shade at room temperature, and a healthy 4-instar fall armyworm that had been starved for 24 h was placed in it. There were 3 replicates in each group, and 1 replicate had 15 fall armyworms. At the same time, a blank control without dihydromaleimide (containing 0.1% Tween 80) and a reference agent control (2 mL of 0.5% azadirachtin emulsifiable concentrate + 8 mL deionized water) were set up. The mortality of fall armyworms at 24 h and 48 h was counted.

[0042] 2. Experimental Results The results are as follows Figure 2 The results showed that the mortality rate of fall armyworm larvae increased with the increase of dihydromaleimide concentration after eating corn leaves soaked in dihydromaleimide solution. The 24 h LC value of dihydromaleimide on fall armyworm was 50 The LC value of 3.417 mg / mL at 48 h 50 It is 2.600 mg / mL.

[0043] Example 4 Determination of the insecticidal activity of dihydromaleimide against white grubs 1. Experimental Methods According to the "Guidelines for Indoor Bioassay Tests of Pesticides - Part 10: Artificial Diet Mixing Method", the larvae of the white-flowered scarab beetle (grub) ( Protaetia brevitarsis ) were used as test pests, and the stomach poison activity of dihydromaleimide was tested.

[0044] In this example, the insecticidal activity of the (R)-configuration dihydromaleimide prepared in Example 2 against white grubs was tested, and the steps were as follows: Dissolve it in 10 mL of deionized water and mix it 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 dry it in the shade; put 15 healthy 3-year-old grubs into the soil of each treatment concentration, with 3 replicates in each group; set up a blank control without dihydromaleimide and a reference agent control (using 0.5% azadirachtin emulsifiable concentrate to make the azadirachtin concentration in the fermented cow dung soil 1.67 mg / g). Count the death of grubs at 24 h and 48 h.

[0045] 2. Experimental Results The results are as follows Figure 3The results showed that the insecticidal activity of the amide compounds against grubs was comparable to that of azadirachtin emulsifiable concentrate, and the 24 h LC value of dihydromaleimide against grubs was 50 LC value of 1.788 mg / g at 48 h 50 It is 1.721 mg / g.

[0046] Example 5 Determination of the insecticidal activity of dihydromaleimide against the bee stink bug 1. Experimental Methods According to the Guidelines for Indoor Bioassay Tests of Pesticides - Part 14: Leaf Dip Method, the bee stink bug ( Riptortus pedestris ) were used as test pests, and the stomach poison activity of dihydromaleimide was tested.

[0047] In this example, the insecticidal activity of the (R)-configuration dihydromaleimide prepared in Example 2 against the bee stink bug was tested in the following steps: The amide compound was prepared with deionized water to obtain 20 mg / mL, 10 mg / mL, 5 mg / mL, 2.5 mg / mL, and 1.25 mg / mL aqueous solutions (containing 0.1% Tween 80); 3 fresh 7 cm long green beans were soaked in the solution for about 12 h, then properly dried in the shade, and fed to 10 healthy 3-year-old bee-margin bugs in a breeding box, with 4 replicates for each concentration; at the same time, a blank control without dihydromaleimide (containing 0.1% Tween 80) and a reference agent control group (7.5 mL of 0.5% azadirachtin emulsifiable concentrate + 22.5 mL deionized water) were set up; the mortality of bee-margin bugs after 72 h was counted.

[0048] 2. Experimental Results The results are as follows Figure 4 The results showed that the mortality rate of the bee-edge bug after consuming green beans soaked in a solution of extremely high concentration (20 mg / mL) of dihydromaleimide was still less than 50%, which was significantly lower than the insecticidal activity against the first two pests. The LC value at 72h was 50 It is 27.030 mg / mL.

[0049] The larvae and grubs of the fall armyworm both have chewing mouthparts, and they can indiscriminately eat dihydromaleimide into their bodies when feeding. The bee stink bug sucks the juice inside the green beans, and most of the dihydromaleimide remains on the epidermis of the green beans, making it difficult to penetrate into the internal juice of the green beans. This may be the reason why it exhibits lower insecticidal activity against the bee stink bug.

[0050] Example 6 Determination of the antifeedant activity of dihydromaleimide against fall armyworm 1. Experimental Methods According to the "Guidelines for Indoor Bioassay Tests for Pesticides - Part 14: Leaf Dip Method", the fall armyworm ( Spodoptera frugiperda ) were used as the test pests, and the antifeedant activity of dihydromaleimide was tested. In this example, the (R)-configuration dihydromaleimide prepared in Example 2 was tested for its antifeedant activity against fall armyworm, and the steps were as follows: The amide compound was taken and deionized to obtain 3 mg / mL, 1.5 mg / mL, 0.75 mg / mL, 0.375 mg / mL, and 0.1875 mg / mL aqueous solutions (containing 0.1% Tween 80); a circular corn leaf with a vertical area of ​​about 1.5 cm was soaked for 0.5 h, slightly dried in the shade at room temperature, and placed in a feeding cup containing a wet cotton ball; then a healthy 4-instar fall armyworm that had been starved for 6 h was placed, with 5 replicates in each group; at the same time, a blank control without dihydromaleimide 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 was 0.5 mg / mL) were set up; the corn leaf area of ​​​​the surviving individuals after 24 h was counted and photographed, and the feeding refusal rate was calculated.

[0051] 2. Experimental Results The results are as follows Figure 5 It showed that there was no obvious antifeedant activity at low concentrations (dihydromaleimide solution concentrations were 0.1875 mg / mL, 0.375 mg / mL, and 0.75 mg / mL), but when the concentration exceeded 1.5 mg / mL, it showed an increase in concentration, and the antifeedant activity of AFC at medium concentrations 50 Approximately 1.903 mg / mL.

[0052] Example 7 Determination of the absolute dose of dihydromaleimide stomach toxicity to fall armyworm 1. Experimental Methods According to the "Standard Operating Procedures for Pesticide Biological Activity Tests - Insecticide Volume", the fall armyworm ( Spodoptera frugiperda ) were used as the test pests, and the absolute dose value of stomach toxicity of dihydromaleimide was tested.

[0053] In this example, the absolute dose determination of the stomach toxicity of the (R)-configured dihydromaleimide prepared in Example 2 on the fall armyworm was tested, and the steps were as follows: an aqueous solution of the amide compound with a concentration of 32 mg / mL, 16 mg / mL, 8 mg / mL, 4 mg / mL, and 2 mg / mL was prepared; 1 μL of the drug solution was dripped on a small piece of feed, and then fed to a 5-instar fall armyworm that had been starved for 12 hours, with 3 replicates for each concentration and 20 insects in each replicate. After the feed was eaten up, fresh feed without drug solution was supplemented, and a blank control group was set up; the mortality rate of each treatment group was counted every day.

[0054] 2. Experimental Results The results are as follows Figure 6 The results showed that when fall armyworm larvae ate artificial diet containing 32 μg of dihydromaleimide, the mortality rate was close to 100% within 1 day, and the mortality rate at other doses remained almost unchanged, LD 50 The value is approximately 19.058 μg.

Claims

1. A dihydromaleimide, characterized in that The structural formula of the dihydromaleimide is shown in the following formula (I): 。 2. The method for preparing dihydromaleimide according to claim 1, characterized in that: The following steps are involved: S1. Dissolving maleimide and cerium chloride heptahydrate, and then adding sodium borohydride solution for reduction reaction; S2. The solution in step S1 is mixed with silica gel powder and dried into a powder; S3. Separate and purify by column chromatography to obtain dihydromaleimide, and then separate its enantiomers to obtain R-configuration dihydromaleimide shown in formula (I).

3. The preparation method according to claim 2, characterized in that: In the step S1, the mass ratio of maleimide, cerium chloride heptahydrate and sodium borohydride is 5:18-20:1.8-2.

4. The preparation method according to claim 2, characterized in that: The reduction reaction in step S1 is carried out at 0°C to 5°C for more than 1.5 h.

5. The preparation method according to claim 2, characterized in that: The enantiomer separation in step S3 is carried out by supercritical fluid chromatography.

6. Use of the dihydromaleimide according to claim 1 in controlling pests.

7. The use according to claim 6, characterized in that: The method of controlling the pests is to kill the pests or to refuse feeding.

8. The use according to claim 6, characterized in that: The pests are Lepidoptera, Coleoptera or Hemiptera pests.

9. Use of the dihydromaleimide according to claim 1 in the preparation of insecticides or antifeedants.

10. The use according to claim 9, 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.

Images