Use of naphthoquinone compounds in treating plant pests and diseases

Abstract

The application relates to application of naphthoquinone compounds in treatment of plant virus diseases and pest diseases, and discloses that naphthoquinone compounds I-1 to I-8 and II-1 to II-3 exhibit good anti-plant virus disease activity, can well inhibit 14 kinds of plant diseases of tobacco mosaic virus (TMV) and cucumber fusarium, peanut brown spot, apple ring, wheat sharp eyespot, corn small spot, watermelon anthracnose, rice false smut, tomato early blight, wheat scab, rice blast, pepper pythium, rape sclerotinia, cucumber botrytis and the like, and exhibit good killing activity on eight kinds of plant pests of armyworm, cotton bollworm, corn borer, spodoptera exigua, mosquito larvae, aphids, Tetranychus cinnabarinus and diamondback moth.

Description

Technical Field

[0001] This invention relates to the application of naphthoquinone compounds in the treatment of plant diseases and pests, belonging to the field of agricultural protection technology. Background Technology

[0002] Naphthoquinones are natural pigments found in various higher plants and microorganisms, attracting widespread attention due to their unique and excellent pharmacological activities. 1,4-Naphthoquinones, as the most widely distributed class of these pigments, possess antibacterial, antiviral, antitumor, and antimalarial biological activities. Their structures are abundant in various natural products and synthetic drugs, and they have been widely used in pharmaceutical research. For example, plants containing naphthoquinones are widely used in Southeast Asia and South America to treat malignant tumors and parasitic diseases. Juglone and nifedipine are special classes of 1,4-naphthoquinone natural products found in herbaceous plants such as walnut husks and plumeria, and also have wide applications. They have received increasing attention in recent years, but currently lack systematic research in the pesticide field. Juglone and nifedipine have advantages such as simple structure, good water solubility, and simple and low-cost synthesis processes. Their application in the pesticide field would improve the current situation where poor water solubility of pesticides affects their efficacy. Summary of the Invention

[0003] This invention provides the application of naphthoquinone compounds in the control of plant diseases and pests. The naphthoquinone compounds of this patent have excellent activity against plant viral pathogens and insecticides.

[0004] The naphthoquinone compounds of this invention are specifically I-1 to I-8, and II-1 to II-3. R 1 R 2 , R 3 represents the functional groups shown in the structures I-1 to I-8 and II-1 to II-3.

[0005]

[0006] Compared with existing technologies, this invention is the first to discover that naphthoquinone derivatives I-1 to I-8 and II-1 to II-3 exhibit excellent antiviral and antifungal activity against plant viruses and pathogens. They can effectively inhibit 14 plant pathogens, including tobacco mosaic virus (TMV), cucumber wilt, peanut brown spot, apple ring rot, wheat sheath rot, corn small spot, watermelon anthracnose, rice seedling blight, tomato early blight, wheat scab, rice blast, pepper phytosis, rapeseed sclerotium, cucumber gray mold, and rice sheath rot. They also exhibit good activity against eight plant pests, including armyworm, cotton bollworm, corn borer, cabbage moth, mosquito larvae, aphids, carmine spider mite, and diamondback moth. Detailed Implementation

[0007] In the embodiments of the present invention, compounds I-1 and II-1 were prepared according to the following reference: J. Org. Chem., 2021, 86(3): 2602-2620. Compound II-2 was prepared according to the following reference: Bioorg. Med. Chem. Lett., 2013, 23(4): 1032-1035. Compounds I-2 to I-3 were prepared according to the following reference: J. Labelled. Comp. Radiopham., 1982, XIX: 6. Compound I-4 was prepared according to the following reference: J. Org. Chem., 1996, 61: 3031-3033. Compound I-5 was prepared according to the following reference: J. Med. Chem., 2015, 58(16): 6422-34. Compound I-6 was prepared according to the following reference: Eur. J. Med. Chem., 2015, 96: 458-66. Compound I-7 was prepared according to the following reference: Chemistry., 2019, 25(12): 2949-2961. Juglone I-8 and lansaurin II-3 were prepared according to the following reference: Eur. J. Org. Chem., 2018, 2018(19): 2254-2258.

[0008] Example 1: Experimental data of naphthoquinone compounds I-1 to I-8, II-1 to II-3

[0009] I-1: Reddish-brown solid, melting point 148-150℃. 1 H NMR (400MHz, CDCl3) δ8.25 (d, J=7.5Hz, 2H), 8.11 (d, J=7.7Hz, 1H), 7.78 (t, J=7.9Hz, 1H), 7.66 (t, J=7.4Hz, 1H), 7.58-7.47 (m, 3H), 6.68 (d, J=1.1Hz, 1H), 2.16 (d, J=0.8Hz, 3H). 13 C NMR (100MHz, CDCl3) δ184.9, 183.5, 165.1, 149.5, 146.9, 136.9, 134.4, 133.9, 133.7, 130.4, 129.7, 129.4, 128.6, 125.2, 123.7, 16.1.

[0010] I-2: Yellow crystals, melting point 149-151℃. 1H NMR (400MHz, CDCl3) δ8.12-8.05 (m, 1H), 7.89 (dd, J=8.0, 4.7Hz, 2H), 7.74 (td, J=7.9, 4.7Hz, 1H), 7.57 (dd, J=7.1, 4.5Hz, 1H), 7.36 (d, J= 7.8Hz, 2H), 6.92 (dd, J=10.3, 4.6Hz, 1H), 6.83 (dd, J=10.3, 4.6Hz, 1H), 2.47 (d, J=4.5Hz, 3H). 13 C NMR (100MHz, CDCl3) δ 183.8, 182.4, 147.0, 145.8, 140.1, 136.9, 134.5, 133.9, 132.6, 130.0, 129.8, 128.8, 125.8, 124.5, 21.8.

[0011] I-3: Pale yellow solid, melting point 189-191℃. 1 H NMR (400MHz, CDCl3) δ7.78 (d, J=7.6Hz, 1H), 7.68 (t, J=8.0Hz, 1H), 7.31 (d, J=8.4Hz, 1H), 6.76 (d, J=1.3Hz, 1H), 4.02 (s, 3H), 2.16 (d, J= 1.2Hz, 3H). 13 C NMR (100MHz, CDCl3) δ 185.8, 184.58, 159.48, 145.4, 137.9, 134.69, 134.49, 120.09, 119.4, 117.7, 56.5, 15.8.

[0012] I-4: Pale yellow solid, melting point 52-54℃. 1 H NMR (400MHz, CDCl3) δ8.91 (d, J=10.1Hz, 1H), 7.93 (dd, J=7.6, 1.2Hz, 1H), 7.58 (t, J=8.0Hz, 1H), 7.51 (d, J=8.2Hz, 1H), 6.53 (d, J=10.1 Hz, 1H), 4.37 (t, J=6.7Hz, 2H), 1.84-1.75 (m, 2H), 1.49-1.32 (m, 6H), 0.91 (t, J=7.0Hz, 3H). 13 HRMS C16 H 19 O3 + [M+H] + cald.259.1329, found 259.1327.

[0013] I-5: Reddish-brown solid, melting point 108-110℃. 1 H NMR (400MHz, CDCl3) δ8.91 (d, J=10.1Hz, 1H), 7.97 (dd, J=7.5, 0.9Hz, 1H), 7.47 (ddt, J=18.1, 16.7, 5.3Hz, 7H), 6.51 (d, J=10.1Hz, 1H), 5.40 (s, 2H). 13 C NMR (100MHz, CDCl3) δ 165.4, 159.6, 154.8, 141.1, 135.3, 130.8, 128.8, 128.6, 128.4, 127.6, 127.3, 121.4, 118.7, 118.1, 67.5.

[0014] I-6: Reddish-brown solid, melting point 172-174℃. 1 H NMR (400MHz, CDCl3) δ11.72 (s, 1H), 7.69-7.61 (m, 2H), 7.48 (s, 1H), 7.30 (dd, J=8.0, 1.4Hz, 1H). 13 C NMR (100MHz, CDCl3) δ182.9, 181.6, 162.1, 141.2, 139.3, 137.2, 131.7, 124.8, 120.0, 114.0.

[0015] I-7: Reddish-brown oily substance. 1 H NMR (400MHz, CDCl3) δ11.80 (s, 1H), 7.62 (dd, J=16.3, 7.5Hz, 2H), 7.48 (t, J=7.7Hz, 2H), 7.36-7.28 (m, 2H), 7.14 (d, J=7.9Hz, 2H), 5.94 (s, 1H). 13 C NMR (100MHz, CDCl3) δ213.9, 219.4, 184.9, 162.0, 160.2, 152.6, 137.3, 132.0, 130.5, 126.8, 124.1, 121.0, 119.0, 114.0.

[0016] I-8: Orange-yellow crystals, melting point 155-157℃. 1H NMR (400MHz, CDCl3) δ11.88 (s, 1H), 7.62 (d, J=7.6Hz, 2H), 7.27 (dd, J=7.3, 2.1Hz, 1H), 6.93 (s, 2H). 13 C NMR (100MHz, CDCl3) δ190.3, 184.3, 168.4, 139.6, 138.7, 136.6, 124.5, 119.2, 117.7.

[0017] II-1: Brown oily substance. 1 H NMR (400MHz, DMSO-d6) δ11.98 (s, 1H), 9.65 (s, 2H), 7.79-7.30 (m, 3H), 7.05 (s, 1H), 7.02 (s, 1H), 6.48-6.28 (m, 2H). 13 C NMR (100MHz, DMSO-d6) δl89.7, 184.5, 161.0, 160.5, 157.3, 147.5, 137.0, 136.4, 132.6, 132.4, 124.3, 118.3, 115.7, 111.7, 107.1, 103.2.

[0018] II-2: Orange-yellow oily substance, yield 11%. 1 H NMR (400MHz, CDCl3) δ12.18 (s, 1H), 7.65 (d, J=4.8 Hz, 2H), 7.47 (d, J=7.9Hz, 2H), 7.30 (d, J=7.2Hz, 3H), 7.01 (s, 1H), 2.43 (s, 3H). 13 CNMR (100MHz, CDCl3) δ190.1, 184.4, 162.0, 148.3, 140.7, 136.6, 135.7, 132.2, 129.8, 129.4, 129.3, 124.6, 118.7, 110.0, 21.5.

[0019] II-3: Orange needle-like crystal product, melting point 77-79℃. 1 H NMR (400MHz, CDCl3) δ11.98 (s, 1H), 7.63 (dd, J=8.5Hz, 7.5Hz, 1H), 7.61 (dd, J=7.5Hz, 2.5Hz, 1H), 7.25 (dd, J=8.5Hz, 2.5Hz, 1H), 6.82(s,1H),2.21(s,3H). 13C NMR (100MHz, CDCl3) δ190.2, 184.7, 161.1, 149.6, 136.1, 135.4, 131.9, 124.1, 119.2, 115.0, 16.5; HRMS C 11 H9O3 + [M+H] + cald.189.0545, found 189.0552.

[0020] Example 2: Determination of activity against tobacco mosaic virus, the determination procedure is as follows:

[0021] 1. Virus purification and concentration determination:

[0022] Virus purification and concentration determination were performed in accordance with the SOP (Standard Operating Procedure) for tobacco mosaic virus prepared by the Bioassay Laboratory of the Institute of Elementochemistry, Nankai University. The crude virus extract was centrifuged twice with polyethylene glycol, and the concentration was determined. It was then stored at 4°C for later use.

[0023] 2. Preparation of compound solutions:

[0024] After weighing, the original drug was dissolved in DMF to obtain 1×10 5 The stock solution was diluted to μg / mL with an aqueous solution containing 1‰ Tween 80 to the required concentration; the Ningnanmycin preparation was diluted directly with water.

[0025] 3. In vivo protection:

[0026] Select uniformly growing *Nicotiana santalinus* plants at the 3-5 leaf stage and spray the entire plant with the pesticide. Each treatment was replicated three times, with a 1‰ Tween 80 aqueous solution as a control. 24 hours later, sprinkle emery (500 mesh) on the leaves, then use a brush to apply the virus solution lightly twice along the veins on the entire leaf surface, supporting the underside of the leaf with the palm of the hand. The virus concentration was 10 μg / mL. Rinse with running water after inoculation. Record the number of lesions after 3 days and calculate the control efficacy.

[0027] 4. In vivo therapeutic effects:

[0028] Select uniformly growing *Nicotiana sambac* plants at the 3-5 leaf stage. Inoculate the entire leaf with the virus using a paintbrush at a concentration of 10 μg / mL. Rinse with running water after inoculation. After the leaves have dried, spray the entire plant with the pesticide. Each treatment is replicated three times, with a 1‰ Tween 80 aqueous solution as a control. Record the number of lesions after 3 days and calculate the control efficacy.

[0029] 5. In vivo passivation effect:

[0030] Select uniformly growing 3-5 leaf stage *Nicotiana sambac* plants. Mix the pesticide with an equal volume of virus sap, inactivate for 30 minutes, and then inoculate by friction. The virus concentration is 20 μg / mL. Rinse immediately with running water after inoculation. Repeat 3 times. Include a 1‰ Tween 80 aqueous solution as a control. Count the number of lesions after 3 days and calculate the results.

[0031] Inhibition rate (%) = [(Number of control necrotic spots - Number of treated necrotic spots) / Number of control necrotic spots] × 100%

[0032] First, the in vivo inactivation activity against tobacco mosaic virus (TMV) of all compounds was tested at a treatment dose of 500 μg / mL. Compounds with a relative inhibition rate greater than 40% were further tested for in vivo therapeutic and protective activity at a treatment dose of 500 μg / mL, and for in vivo inactivation, therapeutic, and protective activity against TMV at a treatment dose of 100 μg / mL. Positive controls were the commercially available antiviral agents ribavirin and ningnanmycin.

[0033] Table 1. Results of anti-Tobacco Mosaic Virus (TMV) activity tests of naphthoquinone compounds I-1~I-8, II-1~II-3

[0034]

[0035] As can be seen from the data in Table 1, naphthoquinone compounds I-1 to I-8 and II-1 to II-3 all exhibited good anti-TMV activity. Among them, at 500 μg / mL, I-1 showed better activity than ribavirin and has great development value.

[0036] Example 3: Antibacterial activity test, the determination procedure is as follows:

[0037] In vitro sterilization test, bacterial growth rate determination method (plate method):

[0038] A certain amount of the drug was dissolved in an appropriate amount of acetone, and then diluted to the required concentration with an aqueous solution containing 200 μg / mL emulsifier. 1 mL of the drug solution was then injected into each petri dish, followed by 9 mL of culture medium. After mixing, a 50 μg / mL drug-containing plate was prepared. A plate with 1 mL of sterile water added served as a blank control. Mycelial discs were cut along the outer edge of the hyphae using a 4 mm diameter punch and transferred to the drug-containing plate. Each treatment was repeated three times. The petri dishes were incubated in a constant temperature incubator at 24 ± 1℃. After 48 hours, the diameter of the mycelial discs in each treatment was observed, and the average value was calculated. The relative inhibition rate was then compared with the blank control.

[0039]

[0040] Table 2. Results of in vitro bactericidal activity tests of juglone and lansevione derivatives I-1~I-8, II-1~II-3:

[0041]

[0042] At a test concentration of 50 μg / mL, all compounds exhibited broad-spectrum inhibitory activity against 14 tested bacteria. The best inhibitory activity was observed against peanut brown spot, *Phytophthora capsici*, *Rhizoctonia solani*, and apple ring rot. Compound II-3 showed 100% inhibition against peanut brown spot, *Phytophthora capsici*, and *Rhizoctonia solani*, and 85% inhibition against apple ring rot. Furthermore, compound I-2 showed 89% inhibition against apple ring rot, and compound I-7 showed 85% inhibition. Some compounds showed superior inhibitory activity against certain strains compared to the commercially available chlorothalonil, indicating significant development potential.

[0043] Example 4: Insecticidal Activity Test Method

[0044] 1. Activity test against armyworm (Mythimna separata Walker), cotton bollworm (Helicoverpa armigera), fall armyworm (Spodoptera frugiperda), and corn borer (Ostrinia nubilalis Hubner): All insects were normal populations reared indoors. The leaf-dip method was used. The active ingredient was dissolved in acetone to prepare a stock solution. Corn leaves were immersed in the acetone-prepared stock solution. After the solution dried, 10 third-instar larvae were introduced. The main effects were stomach poison and contact killing. Larval feeding was observed. Mortality was checked after three days. Each experiment was repeated two or three times, and the average value was taken.

[0045] 2. Mosquito larval activity test: The mosquito larvae were Culex pipiens pallens,

[0046] The larvae were a normal population raised indoors. The original drug was dissolved in acetone to prepare a stock solution, which was then diluted with water to a specific concentration to prepare a rearing solution. Ten third-instar Culex mosquito larvae were placed in the rearing solution, and the mortality rate was checked after three days. An aqueous solution containing 1 mL of the test solvent was used as a blank control. Each experiment was repeated three times, and the average value was taken.

[0047] Table 3. Insecticidal activity test results of juglone-lansine derivatives I-1~I-8, II-1~II-3:

[0048]

[0049]

[0050] Lanseione II-3 exhibited excellent insecticidal activity; II-2, I-2, and I-3 showed good activity against the spider mite *Tetranychus carmine* at specific concentrations (600 μg / mL or 200 μg / mL); most compounds showed excellent activity against the diamondback moth at a concentration of 600 μg / mL, with half of the compounds showing good activity at a concentration of 200 μg / mL, such as compounds I-2 and I-8. Some compounds showed superior activity against certain pests compared to commercially available varieties, indicating significant development potential.

Claims

1. Application of naphthoquinone compound I-1 in the control of tobacco mosaic virus disease.

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