Azacyclo-alkaloid and application of azacyclo-alkaloid in prevention and treatment of plant viruses

Abstract

The invention relates to the technical field of nitrogen heterocyclic compounds, in particular to nitrogen heterocyclic alkaloid and application thereof in preventing and treating plant viruses. The structural formula of the nitrogen heterocyclic alkaloid is shown in the specification, wherein X is selected from any one of-OCH3,-OCH2CH3 and-O (CH2) 2CH3. An antiviral activity test result shows that the azacyclo-alkaloid series compounds provided by the invention have antiviral activity, and the antiviral activity level of part of azacyclo-alkaloid reaches or even exceeds that of a positive control drug. Therefore, the azacyclo-alkaloid is expected to be applied to prevention and treatment of plant viruses.

Description

[0001] This application is a divisional application of Chinese invention patent application No. 202511213258.4, filed on August 28, 2025, entitled "A nitrogen heterocyclic alkaloid and its application in the prevention and control of plant viruses". Technical Field

[0002] This invention relates to the field of nitrogen heterocyclic compounds, and in particular to a nitrogen heterocyclic alkaloid and its application in the prevention and control of plant viruses. Background Technology

[0003] The control of plant viruses is a crucial issue in global agricultural production. However, due to the complexity of viruses and the diversity of their transmission mechanisms, control faces numerous challenges. Currently, methods for controlling plant viral diseases include agricultural control, biological control, chemical control, and genetic engineering. Chemical control is widely used in agricultural production due to its advantages such as ease of operation and rapid effectiveness.

[0004] Currently, the chemical agents registered on the market for the control of plant viral diseases mainly include ribavirin, morpholine guanidine hydrochloride, chlorobromoisocyanuric acid, cymoxanil, lentinan, and some copper-based preparations. These agents have shown some control effects in practical applications, but their effectiveness is severely hampered by the development of resistance.

[0005] Nitrogen heterocyclic alkaloids are a class of nitrogen-containing secondary metabolites formed by plants during long-term evolution. Due to their unique chemical structure and biological activity, they possess a wide range of antitumor, antibacterial, and immunosuppressive activities. However, research on the biological activity of these compounds has mainly focused on their medicinal activities, with relatively few reports on their applications in the agricultural field, especially in plant antiviral applications. Summary of the Invention

[0006] The present invention aims to at least solve one of the technical problems existing in the related art. Therefore, the first objective of the present invention is to provide a nitrogen heterocyclic alkaloid; the second objective of the present invention is to provide an application of a nitrogen heterocyclic alkaloid in the prevention and control of plant viruses.

[0007] To achieve the first objective, the technical solution adopted by this invention is as follows: A nitrogen-containing heterocyclic alkaloid, the structural formula of which is shown below: ; Wherein, X is selected from any one of -OCH3, -OCH2CH3 and -O(CH2)2CH3; R is selected from any of the following groups: , , ; -(CH2) n CH3, where n is any integer from 1 to 17; -(CH2) m CH(CH3)2, m is selected from 1 or 2; -CH2C(CH3)3, -CH(CH2CH3)(CH2CH2CH3); , where 'a' is any integer from 1 to 8; b is selected from any integer from 1 to 3; R1 is selected from H, halogens and -C(CH3)3; R2 is selected from H, -CH3, halogens, -C(CH3)3, -CF3 or -OCH3.

[0008] Preferably, X is selected from -OCH3; and R is selected from -(CH2). n CH3, where n is selected from 1, 3, 7, 11 or 17.

[0009] Preferably, X is selected from -OCH3, and R is selected from... .

[0010] Preferably, X is selected from -OCH3, and R is selected from... .

[0011] Preferably, X is selected from -OCH3; and R is selected from... R1 is selected from the halogen elements Cl or Br.

[0012] Preferably, X is selected from -OCH3; and R is selected from... R2 is selected from the halogen elements F, Cl or Br.

[0013] To achieve the second objective, the technical solution adopted by this invention is as follows: The application of a nitrogen heterocyclic alkaloid in the control of plant viruses, as described in any of the above-mentioned nitrogen heterocyclic alkaloids.

[0014] Preferably, the virus is selected from tobacco mosaic virus.

[0015] Preferably, the plant is selected from one or more of the Solanaceae, Brassicaceae, Chenopodiaceae, Cucurbitaceae, and Fabaceae families.

[0016] Preferably, the Solanaceae plant is selected from one or more of tobacco, tomato, pepper and eggplant; the Cruciferae plant is selected from one or more of Chinese cabbage, kale and rapeseed; the Chenopodiaceae plant is selected from one or two of spinach and amaranth; the Cucurbitaceae plant is selected from cucumber; and the Leguminosae plant is selected from one or two of green beans and cowpeas.

[0017] The above-described one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects: This invention provides a nitrogen-containing heterocyclic alkaloid. Antiviral activity tests show that all compounds in the series possess antiviral activity, with some nitrogen-containing heterocyclic alkaloids exhibiting antiviral activity levels reaching or even exceeding those of the positive control drug. Therefore, this nitrogen-containing heterocyclic alkaloid shows promise for application in the control of plant viruses.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. The following embodiments are used to illustrate this invention, but cannot be used to limit the scope of this invention.

[0020] A nitrogen-containing heterocyclic alkaloid, the structural formula of which is shown below: In the following embodiments, unless otherwise specified, the experimental methods used are conventional methods, and the materials and reagents used are commercially available, unless otherwise specified, and are carried out in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions.

[0021] Example 1 The synthetic routes for nitrogen heterocyclic alkaloids (a, b, c, and d) are shown below: ; Its preparation process is as follows: I. Preparation of intermediate I.

[0022] Under ice-water bath conditions, diethylformamide (5.9 mL, 53.1 mmol) and chloroform (5 mL) were added to a 100 mL round-bottom flask, followed by the slow addition of phosphorus tribromooxyphosphorus (POBr3) (12.7 g, 44.3 mmol). The reaction was allowed to proceed for 30 min, and then the solvent in the reaction mixture was removed under reduced pressure to obtain a white complex. After cooling to room temperature, chloroform (10 mL) was added, and 4-methoxy-3-pyrrolin-2-one (2 g, 17.7 mmol) was slowly added to the reaction system under ice-water bath conditions to dissolve it. The temperature was then raised to 60 °C, and the reaction was allowed to proceed for 5 h. Thin-layer chromatography (TLC) was used for monitoring. After the reaction was complete, 50 mL of ice water was added to the reaction mixture, and the pH was adjusted to neutral with a 2 mol / L NaOH solution. The mixture separated into two layers. The organic phase was collected, and the aqueous layer was extracted with ethyl acetate. After being combined with the aforementioned organic phase, the aqueous layer was washed with saturated brine, dried over anhydrous Na2SO4, filtered, and the filtrate was concentrated. Then, column chromatography was performed using a mixed solvent of petroleum ether (PE) and ethyl acetate (EA) (PE to EA volume ratio of 5:1) as the eluent to give a yellow solid intermediate I with a yield of 76% and a melting point of 38–40 °C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 6.98(s, 1H), 5.56(s, 1H), 4.08(q, J =7.1Hz, 2H), 3.73(s, 3H), 3.36(q, J =7.2Hz, 2H), 1.26(td, J =7.2, 4.9 Hz, 6H); 13 C NMR (100MHz, CDCl3) d 165.3, 138.7, 133.5, 120.7, 96.4, 58.0, 51.2, 44.6, 14.7, 12.5; HRMS (ESI) m / z: [M+H] ＋ C 10 H 16 BrN2O + The calculated value is 259.0440, and the actual value is 259.0443.

[0023] II. Preparation of intermediate II.

[0024] At room temperature, 1-Boc-pyrrole-2-boronic acid (6.27 g, 29.7 mmol), Na₂CO₃ (6.3 g, 59.4 mmol), and Pd(PPh₃)₄ (2.29 g, 1.98 mmol) were sequentially added to a round-bottom flask containing intermediate I (5.12 g, 19.8 mmol). Then, a 10 wt% aqueous solution of dioxane (70 mL) was added, and the mixture was stirred to dissolve. The mixture was heated to 100 °C and reacted for 3 h. After cooling to room temperature, sodium methoxide (3.21 g, 59.4 mmol) was slowly added to the reaction system. The mixture was then heated to 100 °C and reacted for 2.5 h, with TLC monitoring of the reaction. After the reaction was complete, the pH of the solution was adjusted to neutral with 2 mol / L HCl, and the reaction was allowed to proceed for 15 min. The mixture was then filtered, and the filter cake was washed with water and acetone, dried, and intermediate II was obtained with a yield of 70% and a melting point of 224–227 °C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, DMSO-) d 6) d 11.39(s, 1H), 11.28(s, 1H), 9.31(s, 1H), 6.91(s, 1H), 6.75(d, J =2.1Hz, 1H), 6.27 (s, 1H), 6.16–6.03 (m, 1H), 3.84 (s, 3H); 13 C NMR (100MHz, DMSO-) d 6) d 172.1, 159.1, 133.7, 123.9, 120.8, 117.9, 109.8, 108.8, 91.4, 58.2; HRMS (ESI) m / z: [MH] － C 10 H9N2O2 - The calculated value is 189.0670; the actual value is 189.0669.

[0025] III. Preparation of nitrogen heterocyclic alkaloids a .

[0026] At room temperature, intermediate II (0.1 g, 0.52 mmol) was added to a 25 mL reaction vessel, followed by the addition of 1,2-dichloroethane (10 mL) to dissolve intermediate II. Then, isobutylamine (0.52 mL, 5.2 mmol) and glacial acetic acid (0.3 mL, 5.2 mmol) were added sequentially. The reaction was carried out at 25 °C for 6 h, monitored by TLC. After the reaction was complete, water was added to quench the reaction, and the mixture was extracted with dichloromethane. The organic phase was collected, and the aqueous phase was extracted with dichloromethane. The resulting organic phase was combined with the previously collected organic phase, washed with saturated brine, dried over anhydrous Na₂SO₄, filtered, and the filtrate was concentrated. Column chromatography was then performed using a mixed solvent of PE and EA (PE to EA volume ratio 2:1) as the eluent to obtain a yellow oily nitrogen-containing heterocyclic alkaloid a, with a yield of 75%. 1 H NMR and 13 The spectral data of C NMR are as follows: 1 H NMR (400MHz, CDCl3) d 10.72(s, 1H), 7.30(s, 1H), 7.04(s, 1H), 6.77(s, 1H), 6.27(s, 1H), 5.98(s, 1H), 3.91(s, 3H), 3.29(d, J =6.7Hz, 2H), 2.02(dt, J =13.3, 6.7Hz, 1H), 1.02(d, J =6.7Hz, 6H); 13 C NMR (100MHz, CDCl3) d 163.9, 142.3, 140.7, 124.0, 122.7, 113.2, 110.7, 110.7, 91.2, 58.6, 29.5, 19.8.

[0027] IV. Preparation of nitrogen heterocyclic alkaloids b .

[0028] At room temperature, intermediate II (0.1 g, 0.52 mmol) was added to a 25 mL reaction vessel, followed by the addition of 1,2-dichloroethane (10 mL) to dissolve intermediate II. Then, ethylamine (0.3 mL, 5.2 mmol) and glacial acetic acid (0.3 mL, 5.2 mmol) were added sequentially, and the mixture was heated to 50 °C and reacted for 6 h, monitored by TLC. After the reaction was completed, the reaction was quenched with water, extracted with dichloromethane, and the organic phase was collected. The aqueous phase was extracted with dichloromethane, and the resulting organic phase was combined with the aforementioned organic phase. The mixture was washed with saturated brine, dried over anhydrous Na₂SO₄, filtered, and the filtrate was concentrated. Column chromatography was then performed using a mixed solvent of PE and EA (PE to EA volume ratio 2:1) as the eluent to obtain a yellow oily nitrogen-containing heterocyclic alkaloid b in 85% yield. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 7.51(s, 1H), 7.37–7.30(m, 1H), 7.08–7.02(m, 1H), 6.22(s, 1H), 6.08(s, 1H), 3.86(s, 3H), 3.54(q, J =7.3Hz, 2H), 1.53(s, 9H), 1.37(t, J =7.3Hz, 3H); 13 C NMR (100MHz, CDCl3) d 162.1, 148.4, 142.6, 140.3, 126.1, 124.7, 119.8, 111.9, 110.6, 96.5, 84.9, 58.3, 45.9, 27.9, 15.2; HRMS (ESI) m / z: [M+H] ＋ C 12 H 16 N3O + The calculated value is 218.1288; the actual value is 218.1285.

[0029] V. Preparation of nitrogen heterocyclic alkaloids c .

[0030] At room temperature, intermediate II (0.1 g, 0.52 mmol) was added to a 25 mL reaction vessel, followed by the addition of 1,2-dichloroethane (10 mL) to dissolve intermediate II. Then, phenethylamine (0.6 mL, 5.2 mmol) and glacial acetic acid (0.3 mL, 5.2 mmol) were added sequentially, and the mixture was heated to 50 °C and reacted for 6 h, monitored by TLC. After the reaction was completed, the reaction was quenched with water, extracted with dichloromethane, and the organic phase was collected. The aqueous phase was extracted with dichloromethane, and the resulting organic phase was combined with the aforementioned organic phase. The mixture was washed with saturated brine, dried over anhydrous Na₂SO₄, filtered, and the filtrate was concentrated. Column chromatography was then performed using a mixed solvent of PE and EA (PE to EA volume ratio of 1:2) as the eluent to obtain a yellow oily nitrogen-containing heterocyclic alkaloid b in 85% yield. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 10.61 (s, 1H), 9.56 (s, 1H), 7.29 (m, 5H), 7.16–6.99 (m, 2H), 6.75 (s, 1H), 6.29 (s, 1H), 5.92 (s, 1H), 3.88 (s, 3H), 3.80–3.62 (m, 2H), 3.07 (t, J =7.3Hz, 2H); 13 C NMR (100MHz, CDCl3) d 163.9, 142.5, 140.2, 137.1, 129.0, 128.9, 127.0, 124.3, 122.7, 113.4, 110.8, 91.2, 58.5, 52.4, 36.6, 29.7; HRMS (ESI) m / z: [M+H] ＋ H 20 N3O + The calculated value is 294.1601; the actual value is 294.1602.

[0031] VI. Preparation of nitrogen heterocyclic alkaloids d .

[0032] At room temperature, intermediate II (0.1 g, 0.52 mmol) was added to a 25 mL reaction vessel, followed by the addition of 1,2-dichloroethane (10 mL) to dissolve intermediate II. Then, dodecylamine (0.96 g, 5.2 mmol) and glacial acetic acid (0.3 mL, 5.2 mmol) were added sequentially. The mixture was heated to 50 °C and reacted for 6 h, monitored by TLC. After the reaction was complete, water was added to quench the reaction, followed by extraction with dichloromethane. The organic phase was collected, and the aqueous phase was extracted with dichloromethane. The resulting organic phase was combined with the previously collected organic phase, washed with saturated brine, dried over anhydrous Na₂SO₄, filtered, and the filtrate was concentrated. Column chromatography was then performed using a mixed solvent of PE and EA (PE to EA volume ratio 1:2) as the eluent to obtain a yellow oily nitrogen-containing heterocyclic alkaloid b, with a yield of 54%. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 10.69(s, 1H), 7.31(s, 1H), 7.03(s, 1H), 6.72(d, J =2.8Hz, 1H), 6.31–6.20(m, 1H), 5.93(s, 1H), 3.89(s, 3H), 3.45(t, J =7.2Hz, 2H), 1.84–1.64(m, 2H), 1.52–1.25(m, 18H), 0.86(t, J =6.8Hz, 3H); 13 C NMR (100MHz, CDCl3) d 163.7, 142.2, 140.3, 124.0, 122.7, 113.1, 110.8, 110.7, 91.1, 58.5, 51.0, 31.9, 30.3, 29.6, 29.6, 29.4, 29.4, 29.1, 26.5, 22.7, 14.1; HRMS (ESI) m / z: [M+H] ＋ C 22 H 36 N3O + The calculated value is 358.2853; the actual value is 358.2853.

[0033] Example 2 The synthetic routes for nitrogen-containing heterocyclic alkaloids 3a–3z are shown below: .

[0034] I. Preparation of nitrogen heterocyclic alkaloid 3a .

[0035] At room temperature, intermediate II (0.2 g, 1.04 mmol) and n-butylamine (206 μL, 2.08 mmol) were placed in a 30 mL reaction vessel, followed by the addition of methanol (10 mL) to dissolve them. Finally, 2 mol / L HCl (60 μL) was added, and the mixture was heated to 60 °C and reacted for 7 h. The reaction was monitored by TLC. After the reaction was complete, the solvent was removed under reduced pressure, and the mixture was extracted with ethyl acetate and water. The organic phase was collected, washed with saturated brine, dried over anhydrous Na₂SO₄, filtered, and the filtrate was concentrated. Column chromatography was then performed using a mixture of PE, EA, and acetone (ACE) (PE, EA, and ACE in a volume ratio of 2.5:1:1) as the eluent to obtain a yellow solid nitrogen-containing heterocyclic alkaloid 3a, with a yield of 62% and a melting point of 112–114 °C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 7.31 (s, 1H), 6.98 (dd, J =2.2, 1.2Hz, 1H), 6.76–6.59(m, 1H), 6.24(dd, J =3.6, 2.7Hz, 1H), 5.94(s, 1H), 3.88(s, 3H), 3.41(t, J =7.61Hz, 2H), 1.75–1.61(m, 2H), 1.39(m, 2H), 0.92(t, J =7.4Hz, 3H); 13 C NMR (100MHz, CDCl3) d 163.5, 142.4, 140.5, 123.5, 123.2, 112.5, 111.5, 110.5, 91.3, 58.4, 50.8, 32.3, 19.7, 13.6; HRMS (ESI) m / z: [M+H] ＋ C 14 H 20 N3O + The calculated value is 246.1601; the actual value is 246.1600.

[0036] II. Preparation of nitrogen heterocyclic alkaloids 3b .

[0037] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 62%. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 7.22(m, 1H), 7.01(s, 1H), 6.72(s, 1H), 6.24(dt, J =4.8, 2.4Hz, 1H), 5.93(s, 1H), 3.87(s, 3H), 3.19(d, J =6.4Hz, 2H), 1.01(s, 9H); 13 C NMR (100MHz, CDCl3) d 164.0, 142.5, 141.0, 124.1, 122.7, 113.2, 110.7, 110.7, 91.2, 63.3, 58.5, 32.8, 27.1; HRMS (ESI) m / z: [M+H] ＋ C 15 H 22 N3O + The calculated value is 260.1757; the actual value is 260.1755.

[0038] III. Preparation of nitrogen heterocyclic alkaloids 3c .

[0039] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 55% and a melting point of 121–123 °C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 7.30(s, 1H), 6.98(s, 1H), 6.76–6.62(m, 1H), 6.41–6.16(m, 1H), 5.94(s, 1H), 3.87(d, J =3.7Hz, 3H), 3.43 (dd, J =9.9, 4.8Hz, 2H), 1.75–1.63(m, 1H), 1.59(dd, J =13.6, 7.8Hz, 2H), 0.91(dd, J =6.1, 2.5Hz, 6H); 13 C NMR (100MHz, CDCl3) d 163.5, 142.4, 140.4, 123.7, 123.0, 112.7, 111.3, 110.6, 91.2, 58.4, 49.3, 39.0, 25.5, 22.3; HRMS (ESI) m / z: [M+H] ＋ C 15 H 22 N3O + The calculated value is 260.1757; the actual value is 260.1756.

[0040] IV. Preparation of nitrogen heterocyclic alkaloids (3 days) .

[0041] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 58% and a melting point of 146–148 °C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 7.29(s, 1H), 7.04(s, 1H), 6.84–6.68(m, 1H), 6.27(d, J =2.6Hz, 1H), 5.97(s, 1H), 3.91(s, 3H), 3.55–3.32(m, 2H), 1.67(d, J =5.7Hz, 1H), 1.50–1.17(m, 8H), 0.93(dt, J =14.6, 4.6 Hz, 6H); 13 C NMR (100MHz, CDCl3) d 163.8, 142.3, 140.7, 124.0, 122.7, 113.1, 110.7, 110.7, 91.1, 58.5, 54.3, 40.2, 30.3, 28.6, 23.6, 22.9, 14.1, 10.7; HRMS (ESI) m / z: [M+H] ＋ C 18 H 28 N3O + The calculated value is 302.2227; the actual value is 302.2223.

[0042] V. Preparation of nitrogen heterocyclic alkaloid 3e .

[0043] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 68% and a melting point of 133–135 °C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 7.29 (s, 1H), 6.96 (d, J =0.9Hz, 1H), 6.70(d, J =2.7Hz, 1H), 6.23 (dd, J =3.4, 2.8Hz, 1H), 5.95(s, 1H), 3.86(s, 3H), 3.39(t, J =7.2Hz, 2H), 1.77–1.60(m, 2H), 1.44–1.14(m, 12H), 0.84(t, J =6.8Hz, 3H); 13 C NMR (100MHz, CDCl3) d 163.5, 142.3, 140.5, 123.6, 123.1, 112.6, 110.6, 91.3, 58.4, 51.1, 31.8, 30.4, 29.1, 26.5, 22.6, 14.1; HRMS (ESI) m / z: [M+H] ＋ C 18 H 28 N3O + The calculated value is 302.2227; the actual value is 302.2222.

[0044] VI. Preparation of nitrogen heterocyclic alkaloids 3f .

[0045] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 43% and a melting point of 142–144 °C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 7.31(d, J =10.7Hz, 1H), 7.00(s, 1H), 6.74(d,J =3.4Hz, 1H), 6.32–6.19(m, 1H), 5.97(s, 1H), 3.89(s, 3H), 3.43(t, J =7.2Hz, 2H), 1.79–1.62(m, 2H), 1.25(s, 30H), 0.88(t, J =6.7Hz, 3H); 13 C NMR (100MHz, CDCl3) d 163.5, 142.2, 140.5, 123.5, 123.0, 112.7, 111.2, 110.6, 91.2, 58.4, 51.1, 31.9, 30.4, 29.7, 29.7, 29.6, 29.6, 29.5, 29.4, 29.1, 26.5, 22.7, 14.1; HRMS (ESI) m / z: [M+H] ＋ C 28 H 48 N3O + The calculated value is 442.3792; the actual value is 442.3788.

[0046] VII. Preparation of 3g of nitrogen heterocyclic alkaloids .

[0047] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 43% and a melting point of 129–131°C. 1 H NMR and 13 The spectral data of C NMR are as follows: 1 H NMR (400MHz, CDCl3) d 8.52(d, J =4.9Hz, 2H), 7.64 (d, J =7.8Hz, 1H), 7.55(s, 1H), 7.31–7.17(m, 1H), 6.88(s, 1H), 6.61(dd, J =3.6, 1.1Hz, 1H), 6.32–6.17 (m, 1H), 5.95 (s, 1H), 4.53 (s, 2H), 3.87 (s, 3H); 13 C NMR (100MHz, CDCl3) d163.5, 149.4, 148.8, 140.7, 135.7, 132.2, 123.9, 123.7, 123.4, 122.8, 113.0, 111.9, 110.7, 91.6, 58.4, 52.0.

[0048] 8. Preparation of nitrogen heterocyclic alkaloids (3 hours) .

[0049] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 43% and a melting point of 115–117°C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 7.96 (s, 1H), 7.30 (t, J =7.8Hz, 2H), 7.15(d, J =7.7Hz, 2H), 7.09(t, J =7.3Hz, 1H), 6.85(s, 1H), 6.60(d, J =2.6Hz, 1H), 6.29–6.18 (m, 1H), 6.01 (s, 1H), 3.90 (s, 3H); 13 C NMR (100MHz, CDCl3) d 159.9, 138.7, 132.3, 132.2, 129.3, 128.7, 128.6, 128.6, 124.3, 121.0, 119.1, 110.0, 109.4, 92.3, 58.2; HRMS (ESI) m / z: [M+H] ＋ C 16 H 16 N3O + The calculated value is 266.1288; the actual value is 266.1286.

[0050] IX. Preparation of nitrogen heterocyclic alkaloids 3i .

[0051] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 40% and a melting point of 122–124 °C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 7.92 (s, 1H), 7.41 (d, J =8.5Hz, 2H), 7.05 (d, J =8.3Hz, 2H), 6.92(s, 1H), 6.64(d, J =2.8Hz, 1H), 6.33–6.22 (m, 1H), 6.00 (s, 1H), 3.91 (s, 3H); 13 C NMR (100MHz, CDCl3) d 159.2, 139.5, 132.2, 132.2, 132.2, 132.1, 131.4, 128.7, 128.6, 121.2, 121.0, 117.2, 110.2, 109.6, 91.9, 58.2; HRMS (ESI) m / z: [M+H] ＋ C 16 H 15 BrN3O + The calculated value is 344.0393; the actual value is 344.0388.

[0052] 10. Preparation of nitrogen heterocyclic alkaloids 3j .

[0053] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 44% and a melting point of 127–128 °C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 7.98 (s, 1H), 7.20 (d, J =8.2Hz, 2H), 6.99 (d, J =7.7Hz, 2H), 6.76(s, 1H), 6.55(d, J =2.7Hz, 1H), 6.35–6.17(m, 1H), 6.00(s, 1H), 3.88(s, 3H); 13 C NMR (100MHz, CDCl3) d158.7, 140.3, 132.2, 132.2, 132.1, 131.3, 129.4, 129.1, 128.7, 128.6, 124.6, 120.8, 110.1, 109.1, 91.9, 58.2; HRMS (ESI) m / z: [M+H] ＋ C 16 H 15 ClN3O + The calculated value is 300.0898; the actual value is 300.0897.

[0054] XI. Preparation of 3k nitrogen heterocyclic alkaloids .

[0055] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 39% and a melting point of 122–124 °C. 1 H NMR and 13 The spectral data of C NMR are as follows: 1 H NMR (400MHz, CDCl3) d 7.70 (s, 1H), 7.37 (d, J =8.4Hz, 2H), 7.23 (d, J =8.4Hz, 2H), 7.07(s, 1H), 6.74(d, J =3.0Hz, 1H), 6.25(s, 1H), 5.93(s, 1H), 3.87(s, 3H), 1.31(s, 9H); 13 C NMR (100MHz, CDCl3) d 164.7, 148.6, 144.6, 137.6, 131.3, 128.6, 128.5, 126.6, 124.9, 122.9, 117.3, 114.2, 113.8, 110.7, 92.1, 58.4, 31.3.

[0056] 12. Preparation of 3l of nitrogen heterocyclic alkaloids .

[0057] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 51% and a melting point of 157–159 °C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1H NMR (400MHz, CDCl3) d 7.37(s, 1H), 7.32–7.19(m, 5H), 6.81(s, 1H), 6.62(d, J =2.7Hz, 1H), 6.23–6.16 (m, 1H), 5.94 (s, 1H), 4.42 (s, 2H), 3.80 (s, 3H); 13 C NMR (100MHz, CDCl3) d 162.5, 141.7, 136.8, 128.9, 128.0, 127.8, 124.3, 122.4, 111.2, 110.2, 91.8, 58.3, 55.2; HRMS (ESI) m / z: [M+H] ＋ C 17 H 17 FN3O + The calculated value is 298.1350; the actual value is 298.1349.

[0058] 13. Preparation of nitrogen heterocyclic alkaloids 3m .

[0059] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 56% and a melting point of 136–138 °C. 1 H NMR, 13 C NMR and 19 The spectral data of F NMR are as follows: 1 H NMR (400 MHz, CDCl3) d 7.36–7.27(m, 3H), 7.01(dd, J =14.5, 5.5Hz, 3H), 6.75(d, J =3.0Hz, 1H), 6.26–6.20 (m, 1H), 5.93 (s, 1H), 4.54 (s, 2H), 3.82 (s, 3H); 13 C NMR (100MHz, CDCl3) d 164.2, 163.9, 161.4, 143.0, 139.7, 131.4, 131.4, 129.8, 129.7, 124.3, 122.6, 116.2, 116.0, 113.7, 111.4, 110.9, 91.4, 58.5, 53.0; 19F NMR (376MHz, CDCl3) d -113.25(s).

[0060] XIV. Preparation of nitrogen heterocyclic alkaloids 3n .

[0061] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 63% and a melting point of 128–130°C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 7.35 (s, 1H), 7.19 (d, J =8.3Hz, 2H), 7.04 (d, J =8.2Hz, 2H), 6.68(s, 1H), 6.53(d, J =2.7Hz, 1H), 6.22–6.10 (m, 1H), 5.90 (s, 1H), 4.25 (s, 2H), 3.82 (s, 3H); 13 C NMR (100MHz, CDCl3) d 162.0, 142.3, 136.2, 133.3, 128.9, 128.8, 125.6, 121.4, 109.9, 92.2, 58.2, 55.3; HRMS (ESI) m / z: [M+H] ＋ C 17 H 17 ClN3O + The calculated value is 314.1055; the actual value is 314.1051.

[0062] XV. Preparation of nitrogen heterocyclic alkaloids 3o .

[0063] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 70% and a melting point of 150–152°C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 7.36 (m, 3H), 7.04 (d, J=8.2Hz, 2H), 6.68(s, 1H), 6.53(d, J =2.7Hz, 1H), 6.27–6.10 (m, 1H), 5.90 (s, 1H), 4.25 (s, 2H), 3.82 (s, 3H); 13 C NMR (100MHz, CDCl3) d 162.0, 142.2, 136.5, 131.8, 129.3, 124.9, 121.9, 121.6, 110.5, 110.1, 92.0, 58.2, 55.3; HRMS (ESI) m / z: [M+H] ＋ C 17 H 17 BrN3O + The calculated value is 358.0550; the actual value is 358.0548.

[0064] XVI. Preparation of nitrogen heterocyclic alkaloids 3p .

[0065] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 60% and a melting point of 142–144 °C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 7.36(s, 1H), 7.07(s, 4H), 6.74(s, 1H), 6.57(d, J =2.7Hz, 1H), 6.23–6.14(m, 1H), 5.94(s, 1H), 4.33(s, 2H), 3.81(s, 3H), 2.30(s, 3H); 13 C NMR (100MHz, CDCl3) d 162.3, 141.9, 137.5, 134.1, 129.5, 127.7, 125.2, 121.8, 110.3, 110.0, 92.0, 58.2, 55.1, 31.0, 21.1; HRMS (ESI) m / z: [M+H] ＋ C 18 H 20 N3O + The calculated value is 294.1601; the actual value is 294.1598.

[0066] 17. Preparation of nitrogen heterocyclic alkaloid 3q .

[0067] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 43% and a melting point of 142–144 °C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 7.35 (s, 1H), 7.12 (d, J =8.1Hz, 2H), 6.80(d, J =7.9Hz, 3H), 6.60 (dd, J =3.5, 1.0Hz, 1H), 6.19(t, J =2.9Hz, 1H), 5.93 (s, 1H), 4.35 (s, 2H), 3.80 (s, 3H), 3.74 (s, 3H); 13 C NMR (100MHz, CDCl3) d 162.4, 159.3, 141.6, 129.2, 128.8, 124.7, 122.2, 114.2, 110.8, 110.1, 91.9, 58.2, 55.3, 54.7; HRMS (ESI) m / z: [M+H] ＋ C 18 H 20 N3O2 + The calculated value is 310.1550; the actual value is 310.1546.

[0068] 18. Preparation of nitrogen heterocyclic alkaloids 3r .

[0069] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 62% and a melting point of 133–135°C. 1 H NMR, 13 C NMR, 19 The spectral data of F NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 7.50(d, J=7.9Hz, 2H), 7.43(s, 1H), 7.32–7.23(m, 2H), 6.78(s, 1H), 6.59(d, J =2.9Hz, 1H), 6.23–6.15 (m, 1H), 5.92 (s, 1H), 4.44 (s, 2H), 3.84 (s, 3H); 13 C NMR (100MHz, CDCl3) d 161.8, 142.5, 141.5, 130.0, 129.7, 127.8, 125.7, 125.6, 125.4, 124.5, 122.7, 122.1, 114.7, 110.9, 110.3, 91.9, 58.2, 55.7; 19 F NMR (376MHz, CDCl3) d -62.55; HRMS (ESI) m / z: [M+H] ＋ C 18 H 17 F3N3O + The calculated value is 348.1318; the actual value is 348.1314.

[0070] 19. Preparation of nitrogen heterocyclic alkaloids 3s .

[0071] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 45% and a melting point of 122–124 °C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 7.38(s, 1H), 7.17(s, 4H), 6.84(s, 1H), 6.65(d, J =2.9Hz, 1H), 6.26–6.14(m, 1H), 5.95(s, 1H), 4.41(s, 2H), 3.79(s, 3H), 2.87(dt, J =13.8, 6.9Hz, 1H), 1.21(d, J =6.9Hz, 6H); 13 C NMR (100MHz, CDCl3) d162.5, 148.7, 141.6, 134.1, 127.9, 127.0, 126.6, 122.5, 113.5, 111.4, 110.2, 91.7, 58.3, 54.9, 33.8, 24.0; HRMS (ESI) m / z: [M+H] ＋ The calculated value is C 20 H 24 N3O ＋ 322.1914; the actual value is 322.1917.

[0072] 20. Preparation of 3 tons of nitrogen heterocyclic alkaloids .

[0073] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 54% and a melting point of 133–135 °C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 7.36(s, 1H), 6.93(s, 1H), 6.64(d, J =2.6Hz, 1H), 6.29–6.06(m, 1H), 5.94(s, 1H), 3.87(s, 3H), 3.81(dd, J =12.7, 6.5Hz, 1H), 1.98(dt, J =11.9, 9.2Hz, 2H), 1.78(ddd, J =18.7, 10.5, 6.0Hz, 4H), 1.61(dt, J =8.4, 6.7 Hz, 2H); 13 C NMR (100MHz, CDCl3) d 163.2, 142.4, 139.1, 122.9, 111.9, 110.3, 91.3, 62.3, 58.3, 33.6, 29.7, 23.7; HRMS (ESI) m / z: [M+H] ＋ C 15 H 20 N3O ＋ The calculated value is 258.1601; the actual value is 258.1600.

[0074] 21. Preparation of nitrogen heterocyclic alkaloids 3u .

[0075] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 54% and a melting point of 112–114 °C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 7.38(d, J =12.3Hz, 1H), 7.03 (d, J =1.1Hz, 1H), 6.71(d, J =1.4Hz, 1H), 6.25 (dd, J =3.5, 2.0Hz, 1H), 5.93 (s, 1H), 3.89 (s, 3H), 3.51–3.18 (m, 1H), 2.07–1.99 (m, 2H), 1.92–1.74 (m, 2H), 1.70–1.50 (m, 3H), 1.44–1.18 (m, 3H); 13 C NMR (100MHz, CDCl3) d 163.6, 142.1, 138.4, 124.0, 122.8, 112.9, 110.8, 110.6, 91.1, 59.6, 58.4, 33.2, 24.8, 24.5; HRMS (ESI) m / z: [M+H] ＋ C 16 H 22 N3O + The calculated value is 272.1757; the actual value is 272.1756.

[0076] 22. Preparation of nitrogen heterocyclic alkaloids 3v .

[0077] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 45% and a melting point of 122–124 °C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 7.34(s, 1H), 6.95(s, 1H), 6.69(d, J=3.0Hz, 1H), 6.28–6.15(m, 1H), 5.95(s, 1H), 3.85(s, 3H), 3.57–3.40(m, 1H), 1.99(d, J =5.8Hz, 2H), 1.76(dd, J =21.1, 9.4Hz, 4H), 1.54 (s, 4H), 1.43 (s, 2H); 13 C NMR (100MHz, CDCl3) d 163.4, 142.2, 138.6, 123.4, 123.1, 112.4, 111.3, 110.5, 91.3, 62.3, 58.4, 35.5, 27.8, 23.7; HRMS (ESI) m / z: [M+H] ＋ C 18 H 26 N3O ＋ The calculated value is 300.2070; the actual value is 300.2070.

[0078] 23. Preparation of nitrogen heterocyclic alkaloids (3w) .

[0079] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 54% and a melting point of 132–134 °C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d 7.33(s, 1H), 6.92(s, 1H), 6.65(d, J =2.4Hz, 1H), 6.30–6.10 (m, 1H), 5.94 (s, 1H), 3.86 (s, 3H), 3.59–3.41 (m, 1H), 1.97–1.86 (m, 2H), 1.77 (ddd, J =23.3, 15.1, 6.4Hz, 4H), 1.63–1.40 (m, 8H); 13 C NMR (100 MHz, CDCl3) d 163.3, 142.7, 138.7, 123.9, 122.8, 111.7, 110.2, 91.4, 61.5, 58.3, 32.6, 29.7, 27.0, 25.3, 23.4; HRMS (ESI) m / z: [M+H] ＋ C 17 H 24 N3O ＋ The calculated value is 286.1914; the actual value is 286.1912.

[0080] 24. Preparation of 3x nitrogen heterocyclic alkaloids .

[0081] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen-containing heterocyclic alkaloid 3a, with a yield of 55% and a melting point of 165–167°C. Due to the presence of sterically hindered groups, rotational isomers exist, resulting in a slight variation in the yield of the main product. 1 H NMR, 13 The C NMR and HRMS spectral data are as follows: 1 H NMR (400MHz, CDCl3) δ 7.40 (s, 1H), 6.98 (s, 1H), 6.65 (d, J =3.0Hz, 1H), 6.29–6.15(m, 1H), 5.91(s, 1H), 3.87(s, 3H), 2.16(s, 3H), 1.97(m, 6H), 1.75–1.47(m, 6H); 13 C NMR (100MHz, CDCl3) δ 163.7, 135.3, 132.1, 124.4, 122.4, 113.3, 110.7, 110.5, 91.5, 58.3, 55.9, 42.4, 35.7, 29.7, 29.3; HRMS (ESI) m / z: [M+H] ＋ The calculated value is C 20 H 26 N3O ＋ 324.2070; the actual value is 324.2067.

[0082] 25. Preparation of nitrogen heterocyclic alkaloids 3y .

[0083] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 65% and a melting point of 141–143 °C. 1 H NMR, 13 The spectral data of C NMR and HRMS are as follows: 1 H NMR (400MHz, CDCl3) d7.33(s, 1H), 6.94(s, 1H), 6.69(d, J =2.8Hz, 1H), 6.21(s, 1H), 5.98(s, 1H), 3.88(s, 3H), 3.60–3.30(m, 1H), 1.81(m, 2H), 1.55(m, 2H), 1.45–1.21(m, 18H); 13 C NMR (100MHz, CDCl3) d 163.4, 142.5, 139.1, 123.5, 123.3, 112.2, 111.8, 110.4, 91.3, 58.4, 30.7, 23.6, 23.4, 21.4; HRMS (ESI) m / z: [M+H] ＋ C 22 H 34 N3O ＋ The calculated value is 356.2696; the actual value is 356.2693.

[0084] 26. Preparation of nitrogen heterocyclic alkaloids 3z .

[0085] Besides replacing n-butylamine with The remaining preparation process is the same as that for nitrogen heterocyclic alkaloid 3a, with a yield of 45% and a melting point of 131–133 °C. 1 H NMR and 13 The spectral data of C NMR are as follows: 1 H NMR (400MHz, CDCl3) d 7.10(s, 1H), 6.78(s, 1H), 6.31(s, 1H), 6.03(d, J =1.5Hz, 1H), 5.29(s, 1H), 4.12(q, J =7.2Hz, 1H), 3.91(s, 3H), 1.37–1.18(m, 2H), 0.87(dt, J =6.1, 5.4 Hz, 4H); 13 C NMR (100MHz, CDCl3) d 163.2, 142.8, 124.3, 122.9, 117.2, 113.9, 111.0, 109.2, 92.3, 58.3, 31.6, 29.7, 22.7, 14.1.

[0086] Detection Example 1 The detection process for anti-tobacco mosaic virus activity is as follows: I. Virus purification and concentration determination.

[0087] 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 Elementsology, 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.

[0088] II. Solution preparation, the process is as follows: After weighing, the nitrogen heterocyclic alkaloids and ribavirin technical grade were dissolved in DMF to prepare 1×10 5 The stock solution was diluted to the required concentration with an aqueous solution containing 1‰ Tween 80 at a concentration of µg / mL.

[0089] III. The detection process for in vivo protective effect is as follows: Selected red-flowered tobacco plants with uniform growth at the 3-5 leaf stage. The entire plant was sprayed with the pesticide, with each treatment replicated three times. A 1‰ Tween 80 aqueous solution was used as a control. 24 hours later, 500-mesh emery was sprinkled on the leaves. A brush was used to apply the virus solution lightly along the veins twice across the entire leaf surface, with the palm supporting the underside of the leaf. The virus concentration was 10 µg / mL. After inoculation, the leaves were rinsed with running water. The number of lesions was recorded after 3 days, and the control effect was calculated.

[0090] IV. The detection process for in vivo therapeutic effects is as follows: Select 3-5 leaf stage red-flowered tobacco plants with uniform growth and 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 used as a control. Record the number of lesions after 3 days and calculate the control effect.

[0091] V. Detection of in vivo passivation effect, the process is as follows: Select 3-5 leaf stage tobacco plants with uniform growth. Mix the agent with an equal volume of virus sap and inactivate for 30 minutes. Then, inoculate by friction with the mixture. The virus concentration is 20 µg / mL. Rinse with running water immediately after inoculation. Repeat 3 times. Set up a 1‰ Tween 80 aqueous solution as a control. Count the number of lesions after 3 days and calculate the results.

[0092] The inhibition rate (%) is calculated as follows: [(Number of control necrotic spots - Number of treated necrotic spots) / Number of control necrotic spots] × 100%.

[0093] At a treatment dose of 500 µg / mL, the in vivo passivation, in vivo therapeutic, and protective activities against tobacco mosaic virus were tested for all test substances, and the results are shown in Table 1.

[0094] Table 1. Results of anti-tobacco mosaic virus activity tests of nitrogen heterocyclic alkaloids.

[0095] As shown in Table 1, under the condition of 500 mg / L, all nitrogen heterocyclic alkaloids 3a to 3z have antiviral activity. Among them, the antiviral activity levels of 3b, 3c, a, and d are comparable to those of the positive control drug. The in vivo inactivation, in vivo therapeutic, and in vivo protective activities of nitrogen heterocyclic alkaloids 3d, 3e, 3k, 3v, and 3z are all higher than those of the positive control drug ribavirin. In particular, the relative inhibition rate of in vivo inactivation of nitrogen heterocyclic alkaloid 3z is as high as 53.7±2.4%, the relative inhibition rate of in vivo therapeutic is as high as 51.0±3.8%, and the relative inhibition rate of in vivo protective is as high as 50.6±1.9%.

[0096] In conclusion, under the condition of 500 mg / L, the series of nitrogen heterocyclic alkaloids have inhibitory activity against tobacco mosaic virus and are expected to be applied to the prevention and control of plant viral diseases.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A nitrogen-containing heterocyclic alkaloid, characterized in that, Its structural formula is shown below: ； Wherein, X is selected from -OCH3; R is selected from R1 is selected from any one of H, Cl, Br and -C(CH3)3.

2. The application of a nitrogen heterocyclic alkaloid in the control of plant viruses, characterized in that, The nitrogen heterocyclic alkaloid as described in claim 1, wherein the virus is selected from tobacco mosaic virus.

3. The application of the nitrogen heterocyclic alkaloids as described in claim 2 in the control of plant viruses, characterized in that, The plants are selected from one or more of the Solanaceae, Brassicaceae, Chenopodiaceae, Cucurbitaceae, and Fabaceae families.

4. The application of the nitrogen heterocyclic alkaloids as described in claim 3 in the control of plant viruses, characterized in that, The Solanaceae plants are selected from one or more of tobacco, tomato, pepper and eggplant; the Brassicaceae plants are selected from one or more of Chinese cabbage, kale and rapeseed; the Chenopodiaceae plants are selected from one or two of spinach and amaranth; the Cucurbitaceae plants are selected from cucumber; and the Leguminosae plants are selected from one or two of green beans and cowpeas.

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