Application of pyrazolopyrimidine compound in preparation of medicine for preventing and treating nematodes

Abstract

The invention belongs to the technical field of plant protection, and particularly relates to application of pyrazolopyrimidine compounds in preparation of nematode prevention and treatment medicines.The pyrazolopyrimidine compounds have excellent insecticidal activity on aphelenchoides besseyi, sweet potato stem nematodes and pine wood nematodes, and the application of the pyrazolopyrimidine compounds in preparation of nematode prevention and treatment drugs is broad in application prospect. The compound can be used for preventing and treating aphelenchoides besseyi, sweet potato stem nematodes and pine wood nematodes, and can be used as a potential insecticide.

Description

Technical Field

[0001] The present invention belongs to the technical field of plant protection, and particularly relates to the application of a pyrazolopyrimidine compound in the preparation of a nematode control drug. Background Art

[0002] Pyrazolopyrimidine compounds are compounds with broad-spectrum biological activities. In terms of agricultural biological activities, they have insecticidal, herbicidal, antifungal, antibacterial and anti-plant virus activities. In terms of insecticidal activity, for example: in 2017, Zhang Wenming et al. (Bioorg. Med. Chem. Lett. 2017, 27 (1), 16-20) reported a new type of medium-ion pyrido [1,2-a] pyrimidone with special insecticidal activity to control a variety of insect species; in 2021, Li Guanglong et al. (Chinese Journal of Pesticide Science.2021, 23(5), 845-855) reported a series of phenylpyrazolopyrimidinamine and phenylpyrazolopyrimidone compounds. The insecticidal activity test showed that the compounds N-(1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-1H-pyrazolo[3,4-d]pyrimidin-4-yl)butanamide, 1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-5-methyl-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4-yl)butanamide, The mortality rates of [3,4-d]pyrimidin-4-one, 1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-5-isopropyl-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4-one and 2-(1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-4-oxo-1,4-dihydro-5H-pyrazolo[3,4-d]pyrimidin-5-yl)acetonitrile to diamondback moth at 500 mg / L were between 40% and 73%. In terms of herbicides, in 2019, Kang Qiongwen et al. (Chinese Journal of Synthetic Chemistry. 2019, 27(11), 856-861+866) reported a series of novel 5-arylcarboxamido-6-arylamino-pyrazolo[3,4-d]pyrimidin-4-one derivatives. Some of these compounds showed excellent herbicidal activity against monocotyledons and dicotyledons at a concentration of 100 mg / L. -1The inhibition rates of the compounds 5-(4-fluorobenzamide)-6-(4-chloroanilino)-3-methylthio-1-phenyl-1H-pyrazolo[3,4-d]-pyrimidin-4(5H)-one and 5-(4-pyridinylbenzamide)-6-(4-chloroanilino)-3-methylthio-1-phenyl-1H-pyrazolo[3,4-d]-pyrimidin-4(5H)-one on the stems and roots of rapeseed and barnyard grass were as high as 100%. In 2011, Lu Tao et al. (Journal of Jiangxi Normal University (Natural Science Edition). 2011, 35(01), 10-14) reported a series of 3,6-dialkylthio-1-phenyl-pyrazolo[3,4-d]pyrimidin-4-one derivatives. The preliminary herbicidal activity test results showed that at a mass fraction of 1×10 -4The compounds showed good inhibitory effects on the stems of barnyard grass and the rhizomes of rapeseed; in 2010, Wang Tao et al. (Chinese Journal of Organic Chemistry. 2010, 30(11), 1749-1753) reported a series of 3,6-dialkylthio-1-phenyl-pyrazolo[3,4-d]pyrimidin-4-one derivatives, some of which had excellent inhibitory effects on the growth of roots of monocotyledonous and dicotyledonous plants. In terms of bactericidal activity, in 2022, Li Sihui et al. (Journal of Shanxi Agricultural University (Natural Science Edition. 2022, 42(04), 37-45) reported a series of novel pyrazolo[1,5-a]pyrimidine-3-carbonitrile derivatives. Most of the compounds showed good inhibitory effects on Agrobacterium rhizogenes, with the best inhibitory effect at a concentration of 12 mmol / L. The compound 5-(4-(piperidin-1-yl)piperidinyl)-7-(3-cyano-4-fluorophenylamino)-pyrazolo[1,5-a]pyrimidine-3-carbonitrile had the best antibacterial effect, with an inhibition zone diameter of 42.7 mm. In 2012, Song Xinjian et al. (Chinese Journal of Organic Chemistry) reported a series of novel pyrazolo[1,5-a]pyrimidine-3-carbonitrile derivatives. Most of the compounds showed good inhibitory effects on Agrobacterium rhizogenes, with the best inhibitory effect at a concentration of 12 mmol / L. Chemistry. 2012, 32(04), 755-759) reported a series of 1,3,4-thiadiazole ring pyrazolo[3,4-d]pyrimidine compounds. At a concentration of 50 mg / L, most of the compounds showed good fungicidal activity against wheat blast fungus (Rhizoctonia cerealis); in 2006, Bantwar Shivarama Hola et al. (Bioorganic & Medicinal Chemistry. 2006, 14 (6), 2040-2047) reported a series of novel pyrazolo[3,4-d]pyrimidine derivatives. The compound 1-[8-(trifluoromethyl)quinolin-4-yl]-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4-one showed very good activity against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis. In 2002, Chiara B. Vicentini et al. (J. Agric. Food Chem. 2002, 50 (17) 4839–4845) reported the synthesis and evaluation of a series of pyrazolo[3,4-d]pyrimidine-4-(5H)-thione derivatives against Mycobacterium ash. Significant inhibition of fungal growth was found in the range of 10 to 200 μg / mL. It can be seen that pyrazolopyrimidine compounds play an important role in agricultural biological activity and are important scaffold structures.

[0003] At present, there are no research reports on the use of pyrazolopyrimidine compounds in preventing nematode diseases at home and abroad. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention proposes the use of a pyrazolopyrimidine compound in the preparation of a nematode control drug.

[0005] This is achieved specifically through the following technical solutions:

[0006] A pyrazolopyrimidine compound is used in the preparation of a drug for controlling nematodes. The general formula of the pyrazolopyrimidine compound is as follows:

[0007]

[0008] Among them, R 1 Any one selected from halogen, methyl, difluoromethyl; R 2 is selected from halogen; R 3 is selected from methyl; R 4 is selected from cyano, halogen, hydrogen, ethyl or isopropyl.

[0009] The halogen is any one of fluorine, chlorine, bromine and iodine, and is more preferably chlorine.

[0010] More specifically, the pyrazolopyrimidine compounds are as follows:

[0011] (A) 5,7-dichloropyrazolo[1,5-a]pyrimidine-3-carbonitrile, whose structure is as follows:

[0012]

[0013] (B) 3-bromo-5,7-dichloropyrazolo[1,5-a]pyrimidine, whose structure is as follows:

[0014]

[0015] (C) 5,7-dichloro-3-ethylpyrazolo[1,5-a]pyrimidine, whose structure is as follows:

[0016]

[0017] (D) 5,7-dichloro-3-iodopyrazolo[1,5-a]pyrimidine, whose structure is as follows:

[0018]

[0019] (E)5,7-dichloropyrazolo[1,5-a]pyrimidine, whose structure is as follows:

[0020]

[0021] (F) 5,7-dichloro-2-methylpyrazolo[1,5-a]pyrimidine, whose structure is as follows:

[0022]

[0023] (G) 5,7-dichloro-3-isopropylpyrazolo[1,5-a]pyrimidine, whose structure is as follows:

[0024]

[0025] (H)3,5,7-Trichloropyrazolo[1,5-a]pyrimidine, whose structure is as follows:

[0026]

[0027] (I) 7-chloro-5-(4-fluorophenyl)pyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester, the structure of which is as follows:

[0028]

[0029] (J) 7-chloro-5-(2,4,5-trifluorophenyl)pyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester, the structure of which is as follows:

[0030]

[0031] (K) 7-bromo-5-methylpyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester, the structure of which is as follows:

[0032]

[0033] (L) 7-chloro-5-(2,4-dichlorophenyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows:

[0034]

[0035] (M) 7-chloro-5-(2-fluorophenyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows:

[0036]

[0037] (N)7-(2,2-Difluoroethyl)amino)-5-(difluoromethyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile

[0038]

[0039] (O)7-(2,2-trifluoroethyl)amino)-5-(difluoromethyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows:

[0040]

[0041] (P) 5-(difluoromethyl)-7-((5-(trifluoromethyl)pyridin-2-yl)amino)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows:

[0042]

[0043] (Q) 5-(difluoromethyl)-7-((6-chloropyridin-2-yl)amino)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows:

[0044]

[0045] (R)7-((2-bromoethyl)amino)-5-(difluoromethyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, whose structure is as follows:

[0046]

[0047] (S)7-(4-chlorophenoxy)-5-(4-chlorophenyl)methyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows:

[0048]

[0049] (T)7-(4-fluoromethylphenoxy)-5-(4-chlorophenyl)methyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows:

[0050]

[0051] (U) 7-chloro-5-((4-(trifluoromethyl)phenyl)methyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows:

[0052]

[0053] (V) 7-methoxy-5-methylpyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows:

[0054]

[0055] The nematodes are rice stem nematode, sweet potato stem nematode and pine wood nematode.

[0056] Beneficial effects:

[0057] The pyrazolopyrimidine compound of the present invention shows excellent insecticidal activity against rice stem nematode, sweet potato stem nematode and pine wood nematode, can be used for the prevention and treatment of rice stem nematode, sweet potato stem nematode and pine wood nematode, and is used as a potential insecticide. DETAILED DESCRIPTION

[0058] The specific embodiments of the present invention are further described in detail below, but the present invention is not limited to these embodiments. Any improvement or replacement based on the basic spirit of the present embodiment still falls within the scope of protection required by the claims of the present invention.

[0059] The compound of Example 1 is as follows:

[0060] A: 5,7-dichloropyrazolo[1,5-a]pyrimidine-3-carbonitrile, its structure is as follows:

[0061]

[0062] B: 3-bromo-5,7-dichloropyrazolo[1,5-a]pyrimidine, whose structure is as follows:

[0063]

[0064] C: 5,7-dichloro-3-ethylpyrazolo[1,5-a]pyrimidine, its structure is as follows:

[0065]

[0066] D: 5,7-dichloro-3-iodopyrazolo[1,5-a]pyrimidine, whose structure is as follows:

[0067]

[0068] E: 5,7-dichloropyrazolo[1,5-a]pyrimidine, its structure is as follows:

[0069]

[0070] F: 5,7-dichloro-2-methylpyrazolo[1,5-a]pyrimidine, whose structure is as follows:

[0071]

[0072] G: 5,7-dichloro-3-isopropylpyrazolo[1,5-a]pyrimidine, its structure is as follows:

[0073]

[0074] H: 3,5,7-trichloropyrazolo[1,5-a]pyrimidine, its structure is as follows:

[0075]

[0076] I: 7-chloro-5-(4-fluorophenyl)pyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester, the structure of which is as follows:

[0077]

[0078] J: 7-chloro-5-(2,4,5-trifluorophenyl)pyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester, the structure of which is as follows:

[0079]

[0080] K: 7-bromo-5-methylpyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester, its structure is as follows:

[0081]

[0082] L: 7-chloro-5-(2,4-dichlorophenyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows:

[0083]

[0084] M: 7-chloro-5-(2-fluorophenyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows:

[0085]

[0086] N: 7-(2,2-difluoroethyl)amino)-5-(difluoromethyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile

[0087]

[0088] O: 7-(2,2-trifluoroethyl)amino)-5-(difluoromethyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows:

[0089]

[0090] P: 5-(difluoromethyl)-7-((5-(trifluoromethyl)pyridin-2-yl)amino)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows:

[0091]

[0092] Q: 5-(difluoromethyl)-7-((6-chloropyridin-2-yl)amino)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows:

[0093]

[0094] R: 7-((2-bromoethyl)amino)-5-(difluoromethyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows:

[0095]

[0096] S: 7-(4-chlorophenoxy)-5-(4-chlorophenyl)methyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows:

[0097]

[0098] T: 7-(4-fluoromethylphenoxy)-5-(4-chlorophenyl)methyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows:

[0099]

[0100] U: 7-chloro-5-((4-(trifluoromethyl)phenyl)methyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows:

[0101]

[0102] V: 7-methoxy-5-methylpyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows:

[0103]

[0104] Test Example 1:

[0105] The nematicidal activity of the compounds against pine wood nematode, rice stem nematode and sweet potato stem nematode was determined by the insect immersion method.

[0106] The rice stem nematode was inoculated onto a culture dish covered with Botrytis cinerea. After incubation in a 27°C intelligent biochemical incubator in the dark for 5-7 days, 1-2 culture dishes covered with rice stem nematodes were taken and the rice stem nematodes were flushed out with deionized water. The nematodes were then transferred to a 5mL centrifuge tube and centrifuged for 5 minutes (6000rpm / min). The supernatant was discarded. The concentrated rice stem nematodes were then inoculated onto a new Botrytis cinerea culture dish. After incubation for 24 hours, the rice stem nematodes and eggs in the culture medium were rinsed into a glass culture dish with deionized water. The dish was allowed to stand for 2 hours. The rice stem nematode eggs were adsorbed onto the glass culture dish. The water was then slowly poured out and the glass culture dish was slowly rinsed with deionized water 1-2 times. Deionized water was then added to completely immerse the eggs. The dish was placed in a 27°C intelligent biochemical incubator in the dark for 24 hours, and the second-instar larvae were collected. The same method was used to obtain the second-instar larvae of pine wood nematodes and sweet potato stem nematodes.

[0107] Eight test compounds, A, B, C, D, E, F, G, and H, were weighed and thoroughly dissolved in DMSO before being diluted with 1% Tween 80 aqueous solution to 50 mg / L and 100 mg / L test solutions. Fourteen test compounds, I, J, K, L, M, N, O, P, Q, R, S, T, U, and V, were diluted to 200 mg / L and 100 mg / L test solutions. Approximately 50 nematodes and 300 mL of test solution were added to each well of a 48-well cell culture plate. A test solution without compound was used as a negative control (CK). After 72 hours, the number of dead nematodes and the total number of nematodes in each well were recorded. Finally, the nematicidal activity of the corresponding compounds against the rice stem nematode, sweet potato stem nematode, and pine wood nematode was calculated (Table 1).

[0108] Table 1. Nematicidal activity of compound AH against Acanthodes oryzae, Ditylenchus serrata, and Pinewood nematode

[0109]

[0110] Note: Values are mean ± standard deviation.

[0111] As shown in Table 1, the results show that compounds B, E, F, and H had a 100% lethality against all three nematodes at 100 and 50 mg / L; compound C had a 100% lethality against rice stem nematodes and sweet potato stem nematodes at 100 and 50 mg / L; and compound A had a 100% lethality against sweet potato stems at 100 and 50 mg / L. At the test concentrations of 100 and 50 mg / L, the nematicidal activity of the above compounds was significantly better than that of the new nematicide Tioxazafen.

[0112] Table 2. Nematicidal activity of compound IV against pine wood nematodes

[0113]

[0114] Note: Values are mean ± standard deviation.

[0115] The results shown in Table 2 indicate that compound IV has a low mortality rate against pine wood nematodes. Among them, compound M exhibited the highest mortality rates against pine wood nematodes at 200 mg / L and 100 mg / L, which were 61% and 53.4%, respectively.

[0116] Test Example 2:

[0117] The compounds with a concentration of 100 and 50 mg / L and a lethality rate of 100% in Test Example 1 were further tested for their median lethal concentration (LC50). 50The same method as in Test Example 1 was used to obtain the second-instar larvae of the rice stem nematode, the sweet potato stem nematode, and the pine wood nematode. The same method was used to prepare 5-8 test solutions with different concentration gradients to test their median lethal concentrations. Finally, the LC values of the compound against the second-instar rice stem nematode, the sweet potato stem nematode, and the pine wood nematode were calculated. 50 Values (as shown in Table 3).

[0118] Table 3. LC values of pyrazolopyrimidine compounds against rice stem nematode, sweet potato stem nematode, and pine wood nematode 50 value

[0119]

[0120] Note: Values are mean ± standard deviation.

[0121] The results shown in Table 3 indicate that compounds E, F and H exhibited excellent nematicidal activity against rice stem nematode, sweet potato stem nematode and pine wood nematode. 50 The values were 0.8, 1.1 and 7.0 mg / L, respectively, which were significantly better than the nematicide Tioxazafen.

Claims

1. A pyrazolopyrimidine compound for use in the preparation of a nematode control drug, characterized in that: The general formula of the pyrazolopyrimidine compound is as follows: Among them, R 1 Any one selected from halogen, methyl, difluoromethyl; R 2 is selected from halogen; R 3 is selected from methyl; R 4 is selected from cyano, halogen, hydrogen, ethyl or isopropyl.

2. Use of a pyrazolopyrimidine compound according to claim 1 in the preparation of a drug for controlling nematodes, characterized in that: The halogen is any one of fluorine, chlorine, bromine and iodine.

3. Use of a pyrazolopyrimidine compound according to claim 2 in the preparation of a drug for controlling nematodes, characterized in that: The halogen is chlorine.

4. Use of a pyrazolopyrimidine compound according to claim 1 in the preparation of a drug for controlling nematodes, characterized in that: The pyrazolopyrimidine compounds are as follows: (A) 5,7-dichloropyrazolo[1,5-a]pyrimidine-3-carbonitrile, whose structure is as follows: (B) 3-bromo-5,7-dichloropyrazolo[1,5-a]pyrimidine, whose structure is as follows: (C) 5,7-dichloro-3-ethylpyrazolo[1,5-a]pyrimidine, whose structure is as follows: (D) 5,7-dichloro-3-iodopyrazolo[1,5-a]pyrimidine, whose structure is as follows: (E)5,7-dichloropyrazolo[1,5-a]pyrimidine, whose structure is as follows: (F) 5,7-dichloro-2-methylpyrazolo[1,5-a]pyrimidine, whose structure is as follows: (G) 5,7-dichloro-3-isopropylpyrazolo[1,5-a]pyrimidine, whose structure is as follows: (H)3,5,7-Trichloropyrazolo[1,5-a]pyrimidine, whose structure is as follows: (I) 7-chloro-5-(4-fluorophenyl)pyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester, the structure of which is as follows: (J) 7-chloro-5-(2,4,5-trifluorophenyl)pyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester, the structure of which is as follows: (K) 7-bromo-5-methylpyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester, the structure of which is as follows: (L) 7-chloro-5-(2,4-dichlorophenyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows: (M) 7-chloro-5-(2-fluorophenyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows: (N)7-(2,2-Difluoroethyl)amino)-5-(difluoromethyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile (O)7-(2,2-trifluoroethyl)amino)-5-(difluoromethyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows: (P) 5-(difluoromethyl)-7-((5-(trifluoromethyl)pyridin-2-yl)amino)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows: (Q) 5-(difluoromethyl)-7-((6-chloropyridin-2-yl)amino)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows: (R)7-((2-bromoethyl)amino)-5-(difluoromethyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, whose structure is as follows: (S)7-(4-chlorophenoxy)-5-(4-chlorophenyl)methyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows: (T)7-(4-fluoromethylphenoxy)-5-(4-chlorophenyl)methyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows: (U) 7-chloro-5-((4-(trifluoromethyl)phenyl)methyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows: (V) 7-methoxy-5-methylpyrazolo[1,5-a]pyrimidine-3-carbonitrile, the structure of which is as follows:

5. Use of a pyrazolopyrimidine compound according to any one of claims 1 to 4 in the preparation of a drug for controlling nematodes, characterized in that: The nematodes are rice stem nematode, sweet potato stem nematode and pine wood nematode.

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