Eugenol derivative and application thereof in prevention and treatment of animal parasitic diseases

Abstract

The invention belongs to the technical field of veterinary drugs, and particularly relates to eugenol derivatives and application thereof in preventing and treating parasitic diseases of animals, the eugenol derivatives have remarkably improved acaricidal activity, show an excellent killing effect on various livestock and poultry mites, have low toxicity, do not have obvious harm to livestock and poultry and the environment, and can be applied to prevention and treatment of parasitic diseases of animals. The requirements of green veterinary drug development are met, and high stability is shown under the environmental conditions of illumination, temperature change and the like; the preparation method of the eugenol derivative is green and environment-friendly, is simple and convenient to operate, can be used for large-scale preparation, and has relatively high industrial application potential.

Description

Technical Field

[0001] The invention belongs to the technical field of veterinary medicines, and particularly relates to eugenol derivatives and applications thereof in preventing and treating animal parasitic diseases. Background Art

[0002] Animal acariasis is a type of ectoparasitic disease caused by mites such as scabies, itch mites, Demodex, cutaneous mites, and chiggers that live on the skin or body surfaces of animals. It is highly contagious through contact, but can also be transmitted indirectly, such as through contact with mite-contaminated bedding, utensils, and pens. It affects a wide range of animals, including pigs, sheep, rabbits, and dogs. Affected animals typically exhibit clinical symptoms such as severe itching, skin inflammation, and hair loss. These diseases not only severely damage animal health and production performance, but can also lead to mass mortality and pose a potential threat to human health.

[0003] Currently, the control of animal mite diseases relies primarily on pharmaceuticals, biological control, and immunotherapy. Chemicals are widely used due to their remarkable efficacy, rapid onset, and ease of use. However, while traditional chemical acaricides such as organophosphates, macrolides, and pyrethroids can quickly and effectively kill mites, they are becoming a major global challenge due to their high toxicity, drug residues, environmental pollution, and drug resistance. Therefore, the development of safer, more effective, and environmentally friendly alternatives has become a research hotspot.

[0004] In recent years, active ingredients derived from natural plants have gradually become important in the development of acaricides due to their low toxicity and environmental friendliness, providing a new approach to solving the dilemma of mite prevention and treatment. Among them, eugenol is a natural phenolic compound derived from the plant Eugenia caryophyllata, which has multiple biological activities such as antibacterial, insecticide, and antioxidant. For example, previous research by the inventor's research group found that eugenol and ivermectin can be used to prevent and treat animal mite diseases (see invention patent CN115887479A). However, the inventors discovered that the direct use of eugenol to treat mite diseases has limitations such as insufficient acaricidal activity, high volatility, and poor stability.

[0005] In order to solve the above technical problems, the inventors chemically modified eugenol to prepare its derivatives, which can significantly enhance its acaricidal activity and improve its stability. It is expected to be further developed into a new veterinary drug against animal external parasites with better activity and higher safety, which has important application value. Summary of the Invention

[0006] To achieve the above object, the present invention is implemented according to the following technical solutions:

[0007] A eugenol derivative having acaricidal activity, wherein the general structural formula of the eugenol derivative is as shown in formula (I):

[0008]

[0009] Wherein, R1 is selected from H, C1-C 10 Alkyl, C3-C6 cycloalkyl, substituted aryl, R a -(CH2) n -, one of substituted acyl groups;

[0010] Wherein, R2 is selected from -OR b 、-CH2NHR c 、-CH2OR b One of the following;

[0011] Among them, R a One selected from substituted aryl, 5-6 membered heterocyclic molecule, and C3-C6 cycloalkyl;

[0012] Among them, R b Selected from H, C1-C 10 Alkyl, C3-C6 cycloalkyl, R a -(CH2) n -, one of substituted acyl groups;

[0013] Among them, R c Selected from substituted aryl, C1-C 10 Alkyl, C3-C6 cycloalkyl, R a -(CH2) n - one of;

[0014] Among them, the C 1-10 The alkyl group is an alkyl substituent having 1 to 10 carbon atoms, including any one of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, isopentyl, hexyl, and isohexyl, and alkyl derivatives substituted with different functional groups, wherein the functional group is selected from one of cyano, halo, alkenyl, alkynyl, trifluoromethyl, hydroxyl, carboxyl, and amino;

[0015] Among them, the C 3-6 The cycloalkyl group is one of cyclopropane, cyclobutane, cyclopentane and cyclohexane, and derivatives substituted with different functional groups, wherein the functional group is selected from one or more of cyano, halo, alkenyl, alkynyl, trifluoromethyl, hydroxyl, carboxyl, amino and substituted aryl groups;

[0016] wherein the substituted aryl group is one of 2-monosubstituted, 3-monosubstituted, 4-monosubstituted, 2,4-disubstituted, 3,4-disubstituted, 3,5-disubstituted, 2,6-disubstituted, and 2,4,6-trisubstituted; wherein the substituent on the aryl group is one or more of hydroxyl, methyl, methoxy, cyano, nitro, trifluoromethyl, halogen F, Cl, Br, and I;

[0017] Wherein, the substituted acyl group is C 1-6 Alkyl-substituted acyl, C 3-6 Cycloalkyl-substituted acyl, aryl-substituted benzoyl, Ph-(CH2) n -substituted acyl (n = 1-4); wherein the C 1-6 The alkyl group is an alkyl substituent having 1 to 6 carbon atoms, including one of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, isopentyl, hexyl, isohexyl, and alkyl derivatives substituted with different functional groups, wherein the functional groups are selected from one of cyano, halo, alkenyl, alkynyl, trifluoromethyl, hydroxyl, carboxyl, and amino groups; wherein the cycloalkyl group is one of cyclopropane, cyclobutane, cyclopentane, and cyclohexane, and derivatives substituted with different functional groups, wherein the functional groups are selected from one of One of cyano, halo, alkenyl, alkynyl, trifluoromethyl, hydroxyl, carboxyl, amino, and substituted aryl; wherein the aryl is one of 2-monosubstituted, 3-monosubstituted, 4-monosubstituted, 2,4-disubstituted, 3,4-disubstituted, 3,5-disubstituted, 2,6-disubstituted, and 2,4,6-trisubstituted; wherein the substituent on the aryl is one or more of hydroxyl, methyl, methoxy, cyano, nitro, trifluoromethyl, halogen F, Cl, Br, and I;

[0018] The 5-6 membered heterocyclic molecule is a monocyclic or cyclic molecule containing one or two of the three heteroatoms of nitrogen, sulfur and oxygen;

[0019] Among them, the R a -(CH2) n -The number of CH2 in n, n = 1-6.

[0020] Preferably, the eugenol derivative is any one or more of compounds Eug-01 to Eug-117; the structural formulas of the compounds Eug-01 to Eug-117 are as follows:

[0021]

[0022]

[0023] The second object of the present invention is to provide the use of the eugenol derivative or a pharmaceutically acceptable salt thereof in the preparation of a drug for treating animal parasitic diseases.

[0024] Preferably, the animal parasitic disease is an animal ectoparasitic disease.

[0025] Preferably, the animal external parasites are animal mites.

[0026] Preferably, the animal mites include itch mites, scabies mites or demodex mites.

[0027] The third object of the present invention is to provide a pharmaceutical composition comprising an effective amount of the compound or a pharmaceutically acceptable salt, tautomer, isotopomer or stereoisomer thereof, and at least one pharmaceutically acceptable carrier, excipient or vehicle.

[0028] The fourth object of the present invention is to provide a method for treating animal acariasis, which comprises administering an effective amount of the compound or its pharmaceutically acceptable salt, tautomer, isotopomer or stereoisomer to a subject in need.

[0029] A fifth object of the present invention is to provide a method for inhibiting parasites or parasitic activity in a subject, the method comprising administering to a subject in need thereof an effective amount of the compound or a pharmaceutically acceptable salt, tautomer, isotopomer or stereoisomer thereof.

[0030] The beneficial effects of the present invention are as follows: the present invention provides a eugenol derivative with acaricidal activity, the eugenol derivative has significantly improved acaricidal activity, exhibits excellent killing effects on a variety of livestock and poultry mites, has low toxicity, has no obvious harm to livestock and poultry and the environment, meets the requirements for the development of green veterinary drugs, and exhibits high stability under environmental conditions such as light and temperature changes; the preparation method of the eugenol derivative is green and environmentally friendly, simple to operate, and can be prepared on a large scale, and has high potential for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 For the preparation of Eug-23, the imine compound 1 H NMR spectrum

[0032] Figure 2 For Eug-23 1 H NMR spectrum

[0033] Figure 3 For Eug-53 1 H NMR spectrum

[0034] Figure 4 For Eug-62 1 H NMR spectrum

[0035] Figure 5 For Eug-68 1 H NMR spectrum

[0036] Figure 6 For Eug-70 1 H NMR spectrum

[0037] Figure 7 For Eug-72 1 H NMR spectrum

[0038] Figure 8 For Eug-92 1 H NMR spectrum

[0039] Figure 9 For Eug-104 1 H NMR spectrum DETAILED DESCRIPTION

[0040] The following examples may help those skilled in the art better understand the present invention, but are not intended to limit the present invention in any way. The starting materials used in the present invention are all known compounds, which can be purchased from the market or prepared by methods known in the art.

[0041] In the following examples, the methods used are all conventional methods, and the reagents used are all commercially available.

[0042] It should be noted that the inventors synthesized a total of 117 compounds in this invention. To make the patent scheme more concise and clear, the following preparation examples only provide the preparation methods of some compounds, and detailed preparation methods for other compounds are not provided. However, those skilled in the art can obtain other compounds by slightly modifying the parameters based on the provided preparation methods. Alternatively, the compounds can be prepared by other methods in the art. Alternatively, the inventors can be asked to provide specific preparation methods, and the inventors will provide them in detail.

[0043] Example 1. Preparation of compound Eug-23

[0044] Step 1: Add magnesium sulfate (1.81 g, 15 mmol) and 20 mL of anhydrous ethanol to a dry flask, followed by addition of ethanolamine (0.6 g, 10 mmol) under argon protection. After stirring for 10 minutes, add 5-allyl-3-methoxysalicylaldehyde (1.92 g, 10 mmol). The reaction mixture was stirred at room temperature overnight. After the reaction was completed, the reaction mixture was filtered through a diatomaceous earth layer, and the solvent of the filtrate was evaporated to dryness under reduced pressure. The product was purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 8:1) to finally obtain an imine compound as a yellow solid with a yield of 1.99 g and a yield of 85%. 1 H NMR spectrum Figure 1 As shown, the details are as follows: 1 H NMR(500MHz,Chloroform-d)δ8.33(d,J=1.3Hz,1H),6.74(d,J=2.1Hz,1H),6.68(d,J=2.0Hz,1H),5.99–5. 88(m,1H),5.07(ddt,J=14.0,3.1,1.6Hz,2H),3.89(d,J=9.9Hz,5H),3.76–3.71(m,2H),3.33–3.29(m,2H).

[0045] Step 2: In a dry 25 ml round-bottom flask, the imine compound (0.1 g, 0.43 mmol) obtained in the first step was dissolved in 3 mL of methanol and stirred in an ice bath for 10 minutes. Sodium cyanoborohydride (22 mg, 0.52 mmol) was subsequently added. The reaction progress was monitored by thin layer chromatography (TLC) until the substrate was completely reacted. Water (10 mL) was added to terminate the reaction. The mixture was then extracted with ethyl acetate (3 × 25 mL). After combining the organic layers, they were dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The product was purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 4 / 1) to obtain the target compound Eug-23 as a colorless oil with a yield of 89.80 mg and a yield of 88%.

[0046] The target compound Eug-23 1 H NMR spectrum Figure 2 As shown, the details are as follows 1 H NMR(500MHz,Chloroform-d)δ6.61(d,J=2.0Hz,1H),6.45(d,J=1.9Hz,1H),5.93(ddt,J=16.8,10.0,6.7Hz,1H), 5.08–5.01(m,2H),3.96(s,2H),3.84(s,3H),3.75–3.71(m,2H),3.27(dt,J=6.8,1.6Hz,2H),2.81–2.75(m,2H).

[0047] Example 2. Preparation of Compound Eug-40

[0048] In a 75 ml dry round-bottom flask, compound Eug-23 (0.237 g, 1 mmol) and K2CO3 (1.14 g, 8 mmol) were dissolved in 18 mL of acetone and placed in an oil bath and stirred at room temperature for 10 minutes. Dimethyl sulfate (0.51 mL, 5.2 mmol) was then added dropwise quickly, and the reaction system was heated to 60°C and refluxed for 6 hours. After confirming that the substrate was completely reacted by thin layer chromatography (TLC), ammonia water (15 mL) was added dropwise to quench the reaction. After the reaction was cooled to room temperature, it was filtered through a sand core funnel to remove residual potassium carbonate. The filtrate was extracted with ethyl acetate (3 × 25 mL), and the organic phase was dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The resulting product was purified by silica gel column chromatography (petroleum ether / ethyl acetate 8 / 1) to obtain compound Eug-40 as a yellow oil with a yield of 0.22 g and a yield of 88%.

[0049] 1 H NMR(500MHz,Chloroform-d)δ6.61(d,J=2.0Hz,1H),6.45(d,J=1.9Hz,1H),5.93(ddt,J=16.8,10.0,6.7Hz,1H),5.08– 5.01(m,2H),3.96(s,2H),3.86(s,3H),3.84(s,3H),3.75–3.71(m,2H),3.27(dt,J=6.8,1.6Hz,2H),2.81–2.75(m,2H).

[0050] Example 3. Preparation of Compound Eug-41

[0051] Step 1: Magnesium sulfate (1.81 g, 15 mmol) and 20 mL of anhydrous ethanol were added to a dry flask, followed by the addition of 3-aminopentane (0.87 g, 10 mmol) under argon. After stirring for 10 minutes, 5-allyl-3-methoxysalicylaldehyde (1.92 g, 10 mmol) was added. The reaction mixture was stirred at room temperature overnight. After completion of the reaction, the reaction mixture was filtered through a pad of celite, and the solvent of the filtrate was evaporated to dryness under reduced pressure. The resulting product was purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 8:1) to obtain the imine compound as a yellow solid. The imine compound (0.11 g, 0.43 mmol) was dissolved in 3 mL of methanol and stirred in an ice bath for 10 minutes. Sodium cyanoborohydride (22 mg, 0.52 mmol) was then added. The reaction progress was monitored by thin-layer chromatography (TLC) until the substrate was completely reacted. Water (10 mL) was added to terminate the reaction. The mixture was then extracted with ethyl acetate (3×25 mL). The combined organic layers were dried over anhydrous NaSO, filtered, and concentrated under reduced pressure. The resulting product was purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 4 / 1) to obtain the reduced product Eug-25 as a colorless oil in an amount of 96.20 mg (yield: 85%).

[0052] 1 H NMR(500MHz,Chloroform-d)δ6.55(d,J=2.0Hz,1H),6.37(d,J=1.9Hz,1H),5.93–5.81(m,1H),5.04–4.94(m,2H),3.85(s,2H) ,3.80(d,J=1.2Hz,1H),3.79(s,3H),3.23–3.19(m,2H),2.47(p,J=5.8Hz,1H),1.49–1.39(m,4H),0.84(td,J=7.4,1.1Hz,6H).

[0053] Step 2: In a 75 ml dry round-bottom flask, compound Eug-25 (0.26 g, 1 mmol) and K2CO3 (1.14 g, 8 mmol) were dissolved in 18 mL of acetone and placed in an oil bath and stirred at room temperature for 10 minutes. Dimethyl sulfate (0.51 mL, 5.2 mmol) was then added dropwise rapidly, and the reaction system was heated to 60°C and refluxed for 6 hours. After confirming complete reaction of the substrate by thin-layer chromatography (TLC), aqueous ammonia (15 mL) was added dropwise to quench the reaction. After the reaction was cooled to room temperature, it was filtered through a fritted funnel to remove residual potassium carbonate. The filtrate was extracted with ethyl acetate (3 × 25 mL), and the organic phase was dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The resulting product was purified by silica gel column chromatography (petroleum ether / ethyl acetate 8 / 1) to obtain compound Eug-41 as a yellow oil with a yield of 0.247 g and a yield of 90%.

[0054] 1 H NMR (500 MHz, Chloroform-d) δ 6.55 (d, J = 2.0 Hz, 1H), 6.37 (d, J = 1.9 Hz, 1H), 5.93–5.81 (m, 1H), 5.04–4.94 (m, 2H), 3.85 (s, 2H), 3.85 (s, 3H), 3.80 (d, J = 1.2 Hz, 1H), 3.79 (s, 3H), 3.23–3.19 (m, 2H), 2.47 (p, J = 5.8 Hz, 1H), 1.49–1.39 (m, 4H), 0.84 (td, J = 7.4, 1.1 Hz, 6H). Example 4 Preparation of Compound Eug-42

[0055] In a dry 50ml round-bottom flask, Eug-25 (0.068g, 0.26mmol) was dissolved in 2mL of dichloromethane and triethylamine (0.11mL, 0.78mmol) and 4-dimethylaminopyridine (16mg, 0.13mmol) were added sequentially with stirring. After the mixture was cooled to 0°C, acetic anhydride (0.04mL, 0.42mmol) was slowly added dropwise. The mixture was then allowed to warm to room temperature and stirred for 30 minutes. After confirming that the substrate had reacted completely by thin-layer chromatography (TLC), the mixture was extracted with dichloromethane, washed with saturated brine, dried over anhydrous Na2SO4, and evaporated to remove the solvent. Finally, the target product Eug-42 was purified by column chromatography (petroleum ether / ethyl acetate, 16 / 1 to 8 / 1 gradient elution) to obtain the target product Eug-42 as a yellow oil with a yield of 72.21mg and a yield of 91%.

[0056] 1H NMR (500 MHz, Chloroform-d) δ 6.55 (d, J = 2.0 Hz, 1H), 6.37 (d, J = 1.9 Hz, 1H), 5.93–5.81 (m, 1H), 5.04–4.94 (m, 2H), 3.85 (s, 2H), 3.80 (d, J = 1.2 Hz, 1H), 3.79 (s, 3H), 3.23–3.19 (m, 2H), 2.47 (p, J = 5.8 Hz, 1H), 2.33 (s, 3H), 1.49–1.39 (m, 4H), 0.84 (td, J = 7.4, 1.1 Hz, 6H). Example 5. Preparation of Compound Eug-48

[0057] In a 75 ml dry round-bottom flask, compound Eug-26 (0.30 g, 1 mmol) and K2CO3 (1.14 g, 8 mmol) were dissolved in 18 mL of acetone and placed in an oil bath and stirred at room temperature for 10 minutes. Dimethyl sulfate (0.51 mL, 5.2 mmol) was then added dropwise quickly, and the reaction system was heated to 60°C and refluxed for 6 hours. After confirming that the substrate was completely reacted by thin layer chromatography (TLC), ammonia water (15 mL) was added dropwise to quench the reaction. After the reaction was cooled to room temperature, it was filtered through a sand core funnel to remove residual potassium carbonate. The filtrate was extracted with ethyl acetate (3 × 25 mL), and the organic phase was dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The resulting product was purified by silica gel column chromatography (petroleum ether / ethyl acetate 8 / 1) to obtain compound Eug-48 as a yellow oil with a yield of 0.264 g and a yield of 84%.

[0058] 1 H NMR(500MHz,Chloroform-d)δ6.73(d,J=1.9Hz,1H),6.65(d,J=2.0Hz,1H),5.95(ddt,J=16.9 ,10.3,6.7Hz,1H),5.47(dt,J=4.4,2.2Hz,1H),5.11–5.04(m,2H),3.88(s,3H),3.76(d,J=6. 6Hz,2H),3.68(s,3H),3.65(td,J=7.0,1.1Hz,2H),3.32(d,J=6.6Hz,2H),2.29(t,J=7.0Hz,2 H),1.97(qd,J=8.0,7.4,3.6Hz,4H),1.61(pd,J=6.1,3.6Hz,2H),1.54(pd,J=6.5,4.0Hz,2H).

[0059] Example 6. Preparation of Compound Eug-53

[0060] Step 1: In a 100 mL dry round-bottom flask, 2,6-dimethoxyphenol (0.93 g, 6.0 mmol) was dissolved in 30 mL of acetone. K₂CO₃ (3.76 g, 27.0 mmol) was added and stirred in an oil bath at room temperature for 10 min. 3-Propylene bromide (1.09 g, 9.0 mmol) was then slowly added dropwise. After the addition was complete, the reaction system was heated to 60°C and refluxed for 16 h. After confirming complete reaction of the substrate by thin-layer chromatography (TLC), the reaction mixture was cooled to room temperature and filtered through a fritted funnel to remove residual potassium carbonate. The mixture was then extracted with ethyl acetate (3 x 25 mL). The resulting organic layer was dried over anhydrous Na₂SO₄, filtered, and concentrated under reduced pressure. The target compound, 2,6-dimethoxy-1-(allyloxy)phenol, was purified by silica gel column chromatography (petroleum ether / ethyl acetate = 16 / 1 to 4 / 1) to obtain 1.12 g of the target compound, 2,6-dimethoxy-1-(allyloxy)phenol, as a colorless oil in a yield of 96%.

[0061] Step 2: Dissolve 2,6-dimethoxy-1-(allyloxy)phenol (1.00 g, 5.15 mmol) in 8 mL of N,N-diethylaniline in a microwave digestion tube. Use a vacuum pump and double-row manifold for approximately 40 minutes to ensure that the gas in the tube is completely replaced with argon. The digestion tube is then placed in a microwave digester set to 700 W. The temperature is ramped to 220°C over 15 minutes and maintained at this temperature for 3 hours. After the reaction is complete, the reaction solution is slowly poured into water and extracted with ethyl acetate (3 × 25 mL). The combined organic phases are then washed three times with 2N HCl (3 × 10 mL) and then with saturated brine (3 × 10 mL). The resulting organic phase is dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (eluted with petroleum ether / ethyl acetate = 32 / 1-16 / 1) to obtain the target compound Eug-53 as a colorless oil with a yield of 0.79 g and a yield of 79%.

[0062] Compound Eug-53 1 H NMR spectrum Figure 3 As shown, the details are as follows: 1 H NMR (500MHz, Chloroform-d) δ6.41(s,2H),5.95(ddt,J=16.8,10.0,6.7Hz,1H),5.39(s,1H),5.12–5.04(m,2H),3.87(s,6H),3.32(dt,J=6.7,1.5Hz,2H).

[0063] Example 7. Preparation of Compound Eug-62

[0064] In a 50 ml dry round-bottom flask, Eug-53 (0.1 g, 0.51 mmol) and K2CO3 (0.21 g, 1.53 mmol) were dissolved in 8 mL of acetone and placed in an oil bath and stirred at room temperature for 10 minutes. Dimethyl sulfate (0.07 mL, 0.76 mmol) was then added dropwise quickly, and the reaction system was heated to 60°C and refluxed for 6 hours. After confirming that the substrate was completely reacted by thin layer chromatography (TLC), ammonia water (15 mL) was added dropwise to quench the reaction. After the reaction was cooled to room temperature, it was filtered through a sand core funnel to remove residual potassium carbonate. The filtrate was extracted with ethyl acetate (3×25 mL), and the organic phase was dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The resulting product was purified by silica gel column chromatography (petroleum ether / ethyl acetate 8 / 1) to obtain the target compound Eug-62 as a yellow oil with a yield of 0.19 g and a yield of 90%.

[0065] Compound Eug-62 1 H NMR spectrum Figure 4 As shown, the details are as follows: 1 H NMR (500MHz, Chloroform-d) δ6.41(s,2H),5.96(ddt,J=16.8,10.0,6.7Hz,1H),5.15–5.05(m,2H),3.85(s,6H),3.82(s,3H),3.33(dt,J=6.7,1.5Hz,2H).

[0066] Example 8. Preparation of Compound Eug-68

[0067] In a 50 ml dry round-bottom flask, Eug-53 (0.05 g, 0.26 mmol) and K2CO3 (0.11 g, 0.78 mmol) were dissolved in 3 mL of N,N-dimethylformamide. After stirring at room temperature in an oil bath for 10 minutes, bromomethylcyclopropane (0.05 g, 0.39 mmol) was slowly added dropwise. After the addition was complete, the reaction system was heated to 80°C and allowed to react for 12 hours. After confirming complete reaction of the substrate by thin-layer chromatography (TLC), the reaction mixture was cooled to room temperature. The remaining potassium carbonate was then removed by filtration through a fritted funnel, and the filtrate was extracted with ethyl acetate (3 × 25 mL). The resulting organic phase was dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. Finally, the product was purified by silica gel column chromatography (petroleum ether / ethyl acetate 8 / 1) to obtain compound Eug-68. It was a yellow oil with a yield of 54.11 mg and a yield of 90%.

[0068] Compound Eug-68 1 H NMR spectrum Figure 5 As shown, the details are as follows: 1H NMR(500MHz,Chloroform-d)δ6.39(s,2H),5.96(ddt,J=16.8,10.0,6.7Hz,1H),5.14–5.04(m,2H),3.82(s,6H),3. 76(d,J=7.1Hz,2H),3.33(dt,J=6.7,1.5Hz,2H),1.34–1.22(m,1H),0.56–0.51(m,2H),0.26(dt,J=6.0,4.5Hz,2H).

[0069] Example 9. Preparation of Compound Eug-70

[0070] In a 50 ml dry round-bottom flask, Eug-53 (0.1 g, 0.51 mmol) and K2CO3 (0.21 g, 1.53 mmol) were dissolved in 8 mL of acetone and placed in an oil bath and stirred at room temperature for 10 minutes. 2-Bromopropane (0.09 g, 0.76 mmol) was slowly added dropwise to the reaction, and the reaction system was heated to 60°C and refluxed for 6 hours. After confirming that the substrate was completely reacted by thin layer chromatography (TLC), ammonia water (15 mL) was added dropwise to quench the reaction. After the reaction was cooled to room temperature, it was filtered through a fritted funnel to remove residual potassium carbonate. The filtrate was extracted with ethyl acetate (3 × 25 mL), and the organic phase was dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The resulting product was purified by silica gel column chromatography (petroleum ether / ethyl acetate 8 / 1) to obtain the target compound Eug-70 as a yellow oil with a yield of 0.11 g and a yield of 92%.

[0071] Compound Eug-70 1 H NMR spectrum Figure 6 As shown, the details are as follows: 1 H NMR(500MHz,Chloroform-d)δ6.40(s,2H),5.97(ddt,J=16.9,10.1,6.8Hz,1H),5.15–5.05(m, 2H), 4.30 (hept, J=6.2Hz, 1H), 3.81 (s, 6H), 3.33 (dd, J=6.8, 1.5Hz, 2H), 1.29 (d, J=6.2Hz, 6H).

[0072] Example 10. Preparation of Compound Eug-72

[0073] In a dry 50 ml round-bottom flask, Eug-53 (0.05 g, 0.28 mmol) and dimethylcarbamoyl chloride (0.09 g, 0.84 mmol) were dissolved in 1 mL of 1% TfOH-CH3CN solution at room temperature. The reaction mixture was stirred at room temperature for 1 hour. The reaction progress was monitored by thin-layer chromatography (TLC). After confirming complete reaction of the substrate, the mixture was extracted with ethyl acetate (3 × 25 mL). The combined organic phases were washed with saturated brine (3 × 10 mL). The mixture was then dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure to obtain the target compound Eug-72 as a colorless oil in a yield of 0.06 g (86%).

[0074] Compound Eug-72 1 H NMR spectrum Figure 7 As shown, the details are as follows: 1 H NMR(500MHz,Chloroform-d)δ6.42(s,2H),5.95(ddt,J=16.8,9.7,6.6Hz,1H),5 .14–5.05(m,2H),3.80(s,6H),3.35(d,J=6.8Hz,2H),3.13(s,3H),3.00(s,3H).

[0075] Example 11. Preparation of Compound Eug-81

[0076] In a dry 50 ml round-bottom flask, Eug-53 (0.05 g, 0.28 mmol) and trifluoropropionyl chloride (0.12 g, 0.84 mmol) were dissolved in 1 mL of 1% TfOH-CH3CN solution at room temperature. The reaction mixture was stirred at room temperature for 1 hour. The reaction progress was monitored by thin-layer chromatography (TLC). After confirming complete reaction of the substrate, the mixture was extracted with ethyl acetate (3 × 25 mL). The combined organic phases were washed with saturated brine (3 × 10 mL). The mixture was then dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure to obtain the target compound Eug-81 as a colorless oil in a yield of 76.61 mg, for a yield of 90%.

[0077] 1H NMR (500MHz, Chloroform-d) δ6.42(s,2H),5.95(ddt,J=16.8,9.7,6.6Hz,1H),5.14–5.05(m,2H),3.80(s,6H),3.35(d,J=6.8Hz,2H),2.99(s,2H).

[0078] Example 12. Preparation of Compound Eug-92

[0079] In a dry 25ml round-bottom flask, 5-allyl-3-methoxy salicylaldehyde (0.1g, 0.48mmol) was dissolved in 3mL of methanol and stirred in an ice bath for 10 minutes. Sodium borohydride (22mg, 0.58mmol) was subsequently added. The reaction progress was monitored by thin layer chromatography (TLC) until the substrate was completely reacted. Water (10mL) was added to terminate the reaction. It was then extracted with ethyl acetate (3×25mL), and after combining the organic layers, they were dried over anhydrous Na2SO4, filtered and concentrated under reduced pressure. The resulting product was purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate = 4 / 1) to obtain the target compound Eug-92 as a colorless oil with an output of 0.09g and a yield of 86%.

[0080] Compound Eug-92 1 H NMR spectrum Figure 8 As shown, the details are as follows: 1 H NMR(500MHz,Chloroform-d)δ6.68(d,J=2.0Hz,1H),6.65(d,J=2.0Hz,1H),6.10(s,1H),5.94(ddt, J=16.8,10.0,6.7Hz,2H),5.12–5.02(m,2H),4.71(s,2H),3.87(s,3H),3.31(dd,J=6.7,1.6Hz,2H).

[0081] Example 13. Preparation of Compound Eug-104

[0082] Step 1: In a 75 mL dry round-bottom flask, compound Eug-92 (0.2 g, 1 mmol) and K2CO3 (1.14 g, 8 mmol) were dissolved in 18 mL of acetone and stirred in an oil bath at room temperature for 10 minutes. Dimethyl sulfate (0.51 mL, 5.2 mmol) was then added dropwise, and the reaction system was heated to 60°C and refluxed for 6 hours. After confirming complete reaction of the substrate by thin-layer chromatography (TLC), aqueous ammonia (15 mL) was added dropwise to quench the reaction. After cooling to room temperature, the reaction mixture was filtered through a fritted funnel to remove residual potassium carbonate. The filtrate was extracted with ethyl acetate (3 × 25 mL), and the organic phase was dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The resulting product was purified by silica gel column chromatography (petroleum ether / ethyl acetate 8 / 1) to obtain the intermediate compound (5-allyl-2,3-dimethoxyphenyl)methanol as a yellow oil in a yield of 0.19 g (91%).

[0083] 1H NMR(500MHz,Chloroform-d)δ6.75(d,J=2.0Hz,1H),6.70(d,J=2.0Hz,1H),5.95(ddt,J=16.8,10. 0,6.8Hz,1H),5.14–5.04(m,2H),4.67(s,2H),3.86(d,J=1.2Hz,6H),3.34(dt,J=6.7,1.5Hz,2H).

[0084] Step 2: In a 25 ml dry round-bottom flask, sodium hydride (44 mg, 1.85 mmol) was dissolved in 3 mL of anhydrous dimethylformamide, and the intermediate compound (5-allyl-2,3-dimethoxyphenyl)methanol (0.32 g, 1.54 mmol) was slowly added at 0 ° C under an argon atmosphere. After addition, the mixture was stirred at the same temperature for 1 hour. Then, allyl bromide (0.28 g, 2.31 mmol) was added dropwise to the reaction system and stirred at room temperature for 1.5 hours. After the reaction was completed, the solvent was removed under reduced pressure and 30 mL of ethyl acetate was added to the mixture. The organic layer was washed with brine (100 mL), dried, filtered, and concentrated under reduced pressure. The obtained product was purified by silica gel column chromatography (petroleum ether / ethyl acetate 32 / 1) to obtain the target compound Eug-104 as a yellow oil with a yield of 0.28 g and a yield of 76%.

[0085] Compound Eug-104 1 H NMR spectrum Figure 9 As shown, the details are as follows: 1 H NMR(400MHz,Chloroform-d)δ6.84(d,J=2.0Hz,1H),6.69(d,J=2.1Hz,1H),6.13–5.8 0(m,2H),5.35–5.29(m,1H),5.22–5.18(m,1H),5.15–5.02(m,2H),4.55(s,2H),4.08 -4.06(m,2H),3.85(s,3H),3.81(s,3H),3.35(d,J=6.7Hz,2H).

[0086] Example 14. Preparation of Compound Eug-105

[0087] In a 50 mL dry round-bottom flask, Eug-95 (0.06 g, 0.26 mmol) and K2CO3 (0.11 g, 0.78 mmol) were dissolved in 3 mL of N,N-dimethylformamide. After stirring at room temperature in an oil bath for 10 minutes, bromomethylcyclopropane (0.05 g, 0.39 mmol) was slowly added dropwise. After the addition was complete, the reaction system was heated to 80°C and allowed to react for 12 hours. After confirming complete reaction of the substrate by thin-layer chromatography (TLC), the mixture was cooled to room temperature. The remaining potassium carbonate was then removed by filtration through a fritted funnel, and the filtrate was extracted with ethyl acetate (3 × 25 mL). The resulting organic phase was dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. Compound Eug-105 was purified by silica gel column chromatography (petroleum ether / ethyl acetate 8 / 1) to afford 61.4 mg of a yellow oil (yield: 82%).

[0088] 1 H NMR(400MHz,Chloroform-d)δ6.84(d,J=2.0Hz,1H),6.69(d,J=2.1Hz,1H),6.1 3–5.80(m,2H),5.35–5.29(m,1H),5.22–5.18(m,1H),5.15–5.02(m,2H),4.55( s,2H),4.08-4.06(m,2H),3.85(s,3H),3.83(d,J=6.7Hz,2H),3.33(dt,J=6.7, 1.5Hz,2H),1.34–1.22(m,1H),0.56–0.51(m,2H),0.26(dt,J=6.0,4.5Hz,2H).

[0089] Example 15. Preparation of Compound Eug-108

[0090] In a dry 50 ml round-bottom flask, Eug-95 (0.08 g, 0.28 mmol) and dimethylcarbamoyl chloride (0.09 g, 0.84 mmol) were dissolved in 1 mL of 1% TfOH-CH3CN solution at room temperature. The reaction mixture was stirred at room temperature for 1 hour. The reaction progress was monitored by thin-layer chromatography (TLC). After confirming complete reaction of the substrate, the mixture was extracted with ethyl acetate (3 × 25 mL). The combined organic phases were washed with saturated brine (3 × 10 mL). The mixture was then dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure to obtain the target compound Eug-108 as a colorless oil in a yield of 69.17 mg, for a yield of 81%.

[0091] 1H NMR(400MHz,Chloroform-d)δ6.84(d,J=2.0Hz,1H),6.69(d,J=2.1Hz,1H),6.13–5.80(m,2H),5.35–5.29(m,1H),5.22–5.1 8(m,1H),5.15–5.02(m,2H),4.55(s,2H),4.08-4.06(m,2H),3.85(s,3H),3.83(d,J=6.7Hz,2H),3.13(s,3H),3.00(s,3H).

[0092] Example 16. Preparation of Compound Eug-117

[0093] In a dry 50ml round-bottom flask, Eug-95 (0.08g, 0.28mmol) and trifluoropropionyl chloride (0.12g, 0.84mmol) were dissolved in 1mL of 1% TfOH-CH3CN solution at room temperature. The reaction mixture was stirred at room temperature for 1 hour. The reaction progress was monitored by thin-layer chromatography (TLC). After confirming complete reaction of the substrate, the mixture was extracted with ethyl acetate (3×25mL). The combined organic phases were washed with saturated brine (3×10mL). The mixture was then dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure to obtain the target compound Eug-117 as a colorless oil in a yield of 86.62mg, a 92% yield.

[0094] 1H NMR(400MHz,Chloroform-d)δ6.84(d,J=2.0Hz,1H),6.69(d,J=2.1Hz,1H),6.13–5.80(m,2H),5.35–5.29(m,1H),5. 22–5.18(m,1H),5.15–5.02(m,2H),4.55(s,2H),4.08-4.06(m,2H),3.85(s,3H),3.83(d,J=6.7Hz,2H),2.99(s,2H).

[0095] Example 17: Determination of the in vitro activity of compounds against itch mites

[0096] 1. Source of parasites

[0097] Natural mites were collected from the ears of New Zealand rabbits with mite disease as test subjects;

[0098] Rabbits naturally infected with scabies display obvious clinical symptoms of scabies. Scabs were removed from severely infected areas (including the ears, toes, nose, tail, and other areas of the body) and placed in a 9cm disposable Petri dish. The dish was then placed in a constant temperature and humidity incubator at 25°C and 70% humidity for a period of time. Once scabies mites were observed to emerge from the scabs and move to an empty area of the dish, active mites were removed using a picker for subsequent experiments.

[0099] 2. Compound Sample Processing

[0100] The compound was weighed and prepared into a 1 mg / mL stock solution with DMSO, which was then diluted with distilled water to 50 μg / mL and 25 μg / mL solutions;

[0101] 3. Determination method

[0102] (1) Pruritic mites: Place a 0.45 μm, 50 mm diameter microporous filter membrane in a 60 mm dish and add 400 μL of the drug solution. Pick 30 mites per dish with a needle, with three replicates per group. Place the mites in the dish containing the drug solution and incubate at 28°C for 24 hours. Record the number of dead mites in each dish and calculate the mortality rate.

[0103] (2) Scabies: Place a 0.45 μm microporous filter membrane with a diameter of 50 mm on a 60 mm dish and add 400 μL of the drug solution. Pick 30 scabies mites per dish with a needle, and repeat three times per group. Place the mites in the dish containing the drug solution and incubate at a constant temperature and humidity of 25°C and 70% for 24 hours. Observe and record the number of dead scabies mites in each dish under a stereomicroscope to calculate the mortality rate.

[0104] At the same time, a blank control group and a positive control group were set up, that is, 1% DMSO, eugenol solution and ivermectin solution were added respectively.

[0105] Mortality rate = number of dead mites / total number of mites × 100%

[0106] Corrected mortality rate = (mortality rate of mites in the compound group - mortality rate of mites in the blank control) / (1 - mortality rate of mites in the blank control) × 100% 4. Results

[0107] Table 1 Mite mortality rate

[0108]

[0109]

[0110]

[0111] Example 18. Evaluation of the Effect of Compounds on Treating Rabbit Ear Mites

[0112] 1. Evaluation criteria for sick rabbits and the degree and scoring criteria for rabbit itch mite infection

[0113] The rabbits were diagnosed with rabbit ear mites based on clinical symptoms, autopsy changes, and microscopic examination of mites. On the 0th, 3rd, and 7th days of the experiment, the ears were examined for inflammatory exudates and scabs, and the presence of mites was examined microscopically. The degree of infection was scored as follows: no exudate or mites (0 point); ear canal exudate but no mites (0.5 point); ear canal with a small amount of scabs and mites (1 point); external auditory canal full of scabs and mites (2 points); ear canal and proximal 1 / 4 of the auricle with scabs and mites (3 points); auricle 1 / 2 full of scabs and mites (4 points); auricle 3 / 4 full of scabs and mites (5 points); the entire auricle full of scabs and mites (6 points).

[0114] 2. Methods

[0115] Compounds Eug-104 and Eug-105 were prepared into a stock solution using DMSO and then diluted with distilled water to a concentration of 2500 μg / mL for treatment. Ivermectin was used as a positive control, and an aqueous solution containing 0.1% DMSO was used as a blank control. The solution was placed in an 80 mL spray bottle and sprayed evenly onto the affected area every other day. The presence of inflammatory exudate and crusting in the ear was recorded, and the presence of mites was examined microscopically after one week.

[0116] 3. Results

[0117] After 5 days of use, Eug-104 and Eug-105 significantly alleviated the clinical symptoms of the diseased rabbits, and some of the scabs fell off. After one week, all the scabs fell off, and there was no inflammatory exudate in the ears. Microscopic examination showed no insects, and the clinically diseased rabbits were cured of ear scabies. Example 19: Evaluation of the efficacy of the compounds in treating clinical canine scabies

[0118] 1. Evaluation criteria for sick dogs

[0119] Use a blunt surgical blade to scrape the skin at the junction of the affected area and the healthy skin until bleeding occurs. Place the scrapings on a clean glass slide and examine under a low-power microscope. If live mites are found, canine scabies is confirmed.

[0120] 2. Methods

[0121] Compound Eug-104 was prepared with DMSO to form a stock solution, which was then diluted with distilled water to a concentration of 2500 μg / mL for treatment. Ivermectin was used as a positive control, and an aqueous solution containing 0.1% DMSO was used as a blank control. The solution was placed in an 80 mL spray bottle and sprayed evenly onto the affected area every other day. Scabbing and hair growth were recorded, and the presence of mites was examined microscopically after 10 days.

[0122] 3. Results

[0123] After 6 days of use, Eug-104 greatly alleviated the clinical symptoms of the sick dogs, and some scabs fell off; after 12 days, all the scabs of the sick dogs fell off, and no insects were found under microscopic examination; after two weeks, the hair of the sick dogs grew normally, and the canine scabies in the clinically sick dogs had been cured.

[0124] In summary, the present invention provides a eugenol derivative with acaricidal activity. The eugenol derivative has significantly improved acaricidal activity, exhibits excellent killing effects on a variety of livestock and poultry mites, has low toxicity, has no obvious harm to livestock and poultry and the environment, meets the requirements for the development of green veterinary drugs, and exhibits high stability under environmental conditions such as light and temperature changes. The preparation method of the eugenol derivative is green and environmentally friendly, simple to operate, and can be prepared on a large scale, and has high potential for industrial application.

[0125] It should be noted that in the above animal experiments, the inventors selected rabbits and dogs for the experiments. However, the compounds of the present invention are essentially effective against mites and can treat any animal that has mites, without being limited to specific animals.

[0126] The present invention is not limited to the above embodiments. Any simple or equivalent changes or modifications made to the above embodiments based on the technical essence of the present invention are within the technical scope of the present invention.

Claims

1. A eugenol derivative having acaricidal activity, characterized in that: The general structural formula of the eugenol derivative is shown in formula (I), Wherein, R1 is selected from H, C1-C 10 Alkyl, C3-C6 cycloalkyl, substituted aryl, R a -(CH2) n -, one of substituted acyl groups; Wherein, R2 is selected from -OR b 、-CH2NHR c 、-CH2OR b One of the following; Among them, R a One selected from substituted aryl, 5-6 membered heterocyclic molecule, and C3-C6 cycloalkyl; Among them, R b Selected from H, C1-C 10 Alkyl, C3-C6 cycloalkyl, R a -(CH2) n -, one of substituted acyl groups; Among them, R c Selected from substituted aryl, C1-C 10 Alkyl, C3-C6 cycloalkyl, R a -(CH2) n - one of; Among them, the C 1-10 The alkyl group is an alkyl substituent having 1 to 10 carbon atoms, including any one of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, isopentyl, hexyl, and isohexyl, and alkyl derivatives substituted with different functional groups, wherein the functional group is selected from one of cyano, halo, alkenyl, alkynyl, trifluoromethyl, hydroxyl, carboxyl, and amino; Among them, the C 3-6 The cycloalkyl group is one of cyclopropane, cyclobutane, cyclopentane and cyclohexane, and derivatives substituted with different functional groups, wherein the functional group is selected from one or more of cyano, halo, alkenyl, alkynyl, trifluoromethyl, hydroxyl, carboxyl, amino and substituted aryl groups; wherein the substituted aryl group is one of 2-monosubstituted, 3-monosubstituted, 4-monosubstituted, 2,4-disubstituted, 3,4-disubstituted, 3,5-disubstituted, 2,6-disubstituted, and 2,4,6-trisubstituted; wherein the substituent on the aryl group is one or more of hydroxyl, methyl, methoxy, cyano, nitro, trifluoromethyl, halogen F, Cl, Br, and I; Wherein, the substituted acyl group is C 1-6 Alkyl-substituted acyl, C 3-6 Cycloalkyl-substituted acyl, aryl-substituted benzoyl, Ph-(CH2) n -substituted acyl (n = 1-4); wherein the C 1-6 The alkyl group is an alkyl substituent having 1 to 6 carbon atoms, including one of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, isopentyl, hexyl, isohexyl, and alkyl derivatives substituted with different functional groups, wherein the functional groups are selected from one of cyano, halo, alkenyl, alkynyl, trifluoromethyl, hydroxyl, carboxyl, and amino groups; wherein the cycloalkyl group is one of cyclopropane, cyclobutane, cyclopentane, and cyclohexane, and derivatives substituted with different functional groups, wherein the functional groups are selected from one of One of cyano, halo, alkenyl, alkynyl, trifluoromethyl, hydroxyl, carboxyl, amino, and substituted aryl; wherein the aryl is one of 2-monosubstituted, 3-monosubstituted, 4-monosubstituted, 2,4-disubstituted, 3,4-disubstituted, 3,5-disubstituted, 2,6-disubstituted, and 2,4,6-trisubstituted; wherein the substituent on the aryl is one or more of hydroxyl, methyl, methoxy, cyano, nitro, trifluoromethyl, halogen F, Cl, Br, and I; The 5-6 membered heterocyclic molecule is a monocyclic or cyclic molecule containing one or two of the three heteroatoms of nitrogen, sulfur and oxygen; Among them, the R a -(CH2) n -The number of CH2 in n, n = 1-6.

2. The eugenol derivative according to claim 1, wherein The eugenol derivative is any one or more of compounds Eug-01 to Eug-117; the structural formulas of the compounds Eug-01 to Eug-117 are as follows:

3. Use of the eugenol derivative or pharmaceutically acceptable salt thereof according to claim 1 or 2 in the preparation of a medicament for treating animal parasitic diseases.

4. The use according to claim 3, characterized in that The animal parasitic diseases are animal external parasitic diseases.

5. The use according to claim 4, characterized in that The animal external parasites are animal mites.

6. The use according to claim 5, characterized in that The animal mites include itch mites, scabies mites or demodex mites.

7. A pharmaceutical composition, characterized in that The pharmaceutical composition comprises an effective amount of the compound according to any one of claims 1 to 2 or a pharmaceutically acceptable salt, tautomer, isotopomer or stereoisomer thereof, and at least one pharmaceutically acceptable carrier, excipient or vehicle.

8. A method for treating animal acariasis, comprising administering to a subject in need thereof an effective amount of the compound according to claim 1 or 2 or a pharmaceutically acceptable salt, tautomer, isotopomer or stereoisomer thereof.

9. A method for inhibiting parasites or parasitic activity in a subject, the method comprising administering to a subject in need thereof an effective amount of the compound according to claim 1 or 2 or a pharmaceutically acceptable salt, tautomer, isotopomer or stereoisomer thereof.

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