2-arylisoquinoline salt type compounds and their use for the preparation of an antifungal fungicide against plant pathogens

Abstract

The present application relates to 2-aryl isoquinoline salt type compound and its application as preparation anti-phytopathogenic fungi fungicide. Its structure is as formula I-III: wherein, R1, R2 selected from hydrogen, halogen, hydroxyl, trifluoromethyl, C1-C6 alkyl and C1-C6 alkoxy;R3 selected from C1-C6 alkyl;X selected from F, Cl and Br;M and n are the integer of 1-4. The compound of the present application has significant inhibitory activity to a variety of plant pathogenic fungi, and can be used for preparing fungicide to prevent and treat crop diseases.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of pesticide fungicides, in particular to 2-aryl isoquinoline salt type compounds and their application as fungicides against plant pathogenic fungi. BACKGROUND

[0002] Isoquinoline alkaloids are common nitrogen-containing heterocyclic natural products in nature, mainly distributed in plants of Papaveraceae, Amaryllidaceae, and Stephania. Berberine, sanguinarine, and cherythrine are very special among isoquinoline alkaloids, containing a quaternary ammonium salt type structure (C=N + ), also known as quaternary ammonium salt type isoquinoline alkaloids, which have significant antibacterial, anti-inflammatory, and antioxidant biological activities, and their development and application have attracted much attention. Natural insecticide 1% sanguinarine wettable powder, feed antibiotic meiyouzhuang, and antibacterial and anti-inflammatory drug berberine hydrochloride have been marketed. The applicant reported two types of 3-aryl isoquinoline compounds and their application as fungicides against plant pathogenic fungi using quaternary ammonium isoquinoline alkaloids: sanguinarine, cherythrine, and berbine as leads. Studies have shown that the isoquinoline skeleton is a potential antibacterial nucleus, which lays an experimental foundation for the creation of natural source fungicides against plant pathogenic fungi (CN115353488B).

[0003] Based on the results of previous studies, the applicant used the quaternary ammonium salt type isoquinoline alkaloid as a lead, adopted the biomimetic pesticide design strategy, simplified the structure of the lead, and combined the use of pharmacophore splicing principle to design and synthesize a series of novel 2-aryl isoquinoline salt type compounds. The biological activity test results prove that the isoquinoline salt type derivatives involved in the present application have antibacterial activity against a variety of plant pathogenic fungi.

[0004] The 2-aryl isoquinoline salt type compounds involved in the present application are new compounds that have not been reported in the literature. Although similar molecules have been reported in the literature, the molecules and their physicochemical data protected by the present application have not been explicitly listed. SUMMARY

[0005] The present application aims to provide 2-aryl isoquinoline salt type compounds and their application as fungicides against plant pathogenic fungi.

[0006] The 2-aryl isoquinoline salt type compounds described in the present application have the structure as shown in formula I-III,

[0007]

[0008] In the formula I-III, R1, R2 are selected from hydrogen, halogen, hydroxyl, trifluoromethyl, C1-C6 alkyl and C1-C6 alkoxy; R3 is selected from C1-C6 alkyl; X is F, Cl and Br; m and n are integers from 1 to 4.

[0009] The present application provides a general preparation method of the 2-aryl isoquinoline salt type compounds I-III, and a typical synthetic route is shown in the following reaction formula 1.

[0010]

[0011] Reaction formula 1

[0012] The compounds I-III have significant inhibitory activity on Rhizotonia cerealis, Physalospora piricola, Fusarium graminearum, Ustilago hordei, Ustilago nuda and Alternaria alternata, etc.

[0013] Compared with the prior art, the present application has the following advantages and effects:

[0014] Based on the natural quaternary ammonium salt type isoquinoline alkaloid as a lead, the strategy of biomimetic design is adopted, the unified biomimetic skeleton--isoquinoline is used as a mother nucleus, the key pharmacophore of amide, succinate dehydrogenase inhibitor and biphenyl fungicide is introduced, a series of novel 2-aryl isoquinoline salt type compounds are designed and synthesized. Through the in vitro antibacterial activity test, it is proved that the plant pathogenic fungal activity of the compounds is significant, and some target compounds are equivalent to the commercial fungicides chlorothalonil and carbendazim, which provides basic data for the synthesis and biological activity research of 2-aryl isoquinoline salt type derivatives. DETAILED DESCRIPTION

[0015] In the present application, the structural general formula of the 2-aryl isoquinoline salt type compounds designed and synthesized is as follows:

[0016] In the formula I-III, R1, R2 are selected from hydrogen, halogen, hydroxyl, trifluoromethyl, C1-C6 alkyl and C1-C6 alkoxy; R3 is selected from C1-C6 alkyl; X is F, Cl and Br; m and n are integers from 1 to 4.

[0017] 2-Arylisochinoline salt compounds for use in the preparation of fungicides against plant pathogenic fungi. It is known that isochinoline compounds have significant inhibitory activity against a variety of plant pathogenic fungi such as Rhizotonia cerealis, Physalospora piricola, Fusarium graminearum, Ustilago hordei, Ustilago nuda, and Alternaria alternata, etc.

[0018] The general synthesis of 2-arylisochinoline salt compounds I-III according to the present application is shown in Reaction Scheme 1. Compound I-1 is shown as an example.

[0019]

[0020] Example 1, synthesis of compound I-1.

[0021] The synthesis route of compound I-1 is shown in Reaction Scheme 2.

[0022]

[0023] Reaction Scheme 2

[0024] Synthesis of intermediate 2a: isochroman 1a (0.05 mol, 6.71 g) and copper bromide (0.06 mol, 13.4 g) were dissolved in 80 mL of acetonitrile and heated to reflux, and thin layer chromatography (TLC) was used to monitor the reaction until it was complete. After cooling, the solvent was removed under reduced pressure, 100 mL of ethyl acetate was added to the residue, and it was washed with saturated brine until it was neutral, dried over anhydrous sodium sulfate, and column chromatography was used to isolate the colorless liquid, which had a yield of 92.6%.

[0025] Synthesis of target compound I-1: 1.0 mmol of 2-amino-5-methylbenzoate 3a was dissolved in 10 mL of acetonitrile, and a solution of intermediate 2a (1.2 mmol) in 5 mL of acetonitrile was added dropwise, and it was stirred overnight. The solvent was removed under reduced pressure, 10 mL of ethyl acetate was added to the residue, it was stirred well, suction filtered, the solid was washed with ethyl acetate, and it was air-dried to obtain the target compound I-1.

[0026] Compound I-1: yellow solid, yield 81.4%; m.p. 166-168°C. 1H NMR (400 MHz, CDC13) δ 9.99 (s, 1H), 8.61 (dd, J = 8.7, 4.7 Hz, 1H), 8.33 (d, J = 7.5 Hz, 1H), 7.86 (dd, J = 8.4, 2.8 Hz, 1H), 7.77 (t, J = 7.5 Hz, 1H), 7.52 - 7.40 (m, 3H), 4.44 (br, 2H), 3.92 (s, 3H), 3.63 (t, J = 7.3 Hz, 2H). 13 C NMR (100 MHz, CDC13) δ 169.26, 163.21, 162.98 (d, J = 255.0 Hz), 138.98, 138.42, 138.39, 136.64, 130.56 (d, J = 8.6 Hz), 128.63, 128.29, 126.43 (d, J = 8.0 Hz), 125.19, 122.04 (d, J = 22.6 Hz), 119.31 (d, J = 22.6 Hz), 54.06, 53.00, 26.21, 21.29.

[0027] The synthesis method of the rest of the target compounds I-III is the same as I-1, and the structural formula of some representative compounds is shown in Table 1.

[0028] The physicochemical data of some representative compounds are as follows:

[0029] Compound I-2: yellow solid, yield 58.7%; mp 154-155°C. 1 H NMR (400 MHz, CDC13) δ 9.99 (s, 1H), 8.61 (dd, J = 8.7, 4.7 Hz, 1H), 8.33 (d, J = 7.5 Hz, 1H), 7.86 (dd, J = 8.4, 2.8 Hz, 1H), 7.77 (t, J = 7.5 Hz, 1H), 7.52 - 7.40 (m, 3H), 4.44 (br, 2H), 3.92 (s, 3H), 3.63 (t, J = 7.3 Hz, 2H). 13 C NMR (100 MHz, CDC13) δ 169.26, 163.21, 162.98 (d, J = 255.0 Hz), 138.98, 138.42, 138.39, 136.64, 130.56 (d, J = 8.6 Hz), 128.63, 128.29, 126.43 (d, J = 8.0 Hz), 125.19, 122.04 (d, J = 22.6 Hz), 119.31 (d, J = 22.6 Hz), 54.06, 53.00, 26.21, 21.29. 1 J CF = 255.0 Hz), 138.98, 138.42, 138.39, 136.64, 130.56 (d, 3 J CF = 8.6 Hz), 128.63, 128.29, 126.43 (d, 3 J CF = 8.0 Hz), 125.19, 122.04 (d, 2 J CF = 22.6 Hz), 119.31 (d, 2 J CF= 25.4 Hz), 54.11, 53.39, 26.15.

[0030] Compound I-3: yellow solid, yield 75.2%; mp 180-182 °C. 1 H NMR (400 MHz, CDC13) δ 10.02 (s, 1H), 8.62 (d, J = 8.5 Hz, 1H), 8.34 (d, J = 7.5 Hz, 1H), 8.15 (d, J = 2.4 Hz, 1H), 7.76 (dd, J = 10.9, 4.2 Hz, 1H), 7.71 (dd, J = 8.5, 2.4 Hz, 1H), 7.47 (t, J = 7.6 Hz, 1H), 7.41 (d, J = 7.6 Hz, 1H), 4.43 (t, J = 7.7 Hz, 3H), 3.92 (s, 3H), 3.62 (t, J = 7.7 Hz, 2H). 13 C NMR (100 MHz, CDC13) δ 169.14, 163.33, 140.74, 139.02, 137.63, 136.82, 136.65, 135.12, 132.21, 129.68, 128.73, 128.30, 125.68, 125.30, 54.03, 53.42, 26.19.

[0031] Compound I-4: yellow solid, yield 74.6%; mp 179-181 °C. 1 H NMR (400 MHz, CDC13) δ 10.03 (s, 1H), 8.54 (d, J = 8.5 Hz, 1H), 8.34 (d, J = 7.6 Hz, 1H), 8.31 (d, J = 2.2 Hz, 1H), 7.86 (dd, J = 8.5, 2.2 Hz, 1H), 7.77 (t, J = 7.6 Hz, 1H), 7.47 (t, J = 7.6 Hz, 1H), 7.41 (d, J = 7.6 Hz, 1H), 4.44 (br, 2H), 3.92 (s, 3H), 3.62 (t, J = 7.8 Hz, 2H). 13 C NMR (100 MHz, CDC13) δ 169.06, 163.21, 141.23, 139.03, 138.13, 136.81, 136.65, 135.13, 129.76, 128.72, 128.30, 125.76, 125.59, 125.28, 53.97, 53.42, 26.18.

[0032] Compound I-5: yellow solid, yield 61.3%; mp 159-161 °C. 1H NMR (400 MHz, CDC13) δ 9.93 (s, 1H), 8.47 (dd, J = 8.2, 2.3 Hz, 1H), 8.31 (d, J = 7.5 Hz, 1H), 8.22 (dd, J = 8.9, 5.7 Hz, 1H), 7.74 (t, J = 7.5 Hz, 1H), 7.39 (s, 1H), 7.36 - 7.30 (m, 1H), 4.44 (br, 2H), 3.87 (s, 3H), 3.62 (br, 2H), 2.62 (s, 3H). 13 C NMR (100 MHz, CDC13) δ 168.96, 165.28 (d, 1 J CF = 261.3 Hz), 163.52, 144.14 (d, 3 J CF = 10.6 Hz), 138.93, 136.78, 136.56, 134.57 (d, 3 J CF = 9.8 Hz), 128.67, 128.26, 125.31, 120.63, 118.63 (d, 2 J CF = 21.2 Hz), 116.25 (d, 2 J CF = 26.3 Hz), 53.87, 53.11, 26.15.

[0033] Compound I-6: yellow solid, yield 81.2%; mp 182-184 °C. 1 H NMR (400 MHz, CDC13) δ 9.98 (s, 1H), 8.61 (d, J = 1.9 Hz, 1H), 8.34 (d, J = 7.6 Hz, 1H), 8.13 (d, J = 8.5 Hz, 1H), 7.74 (d, J = 7.6 Hz, 1H), 7.46 (s, 1H), 7.39 (d, J = 7.6 Hz, 1H), 4.40 (br, 2H), 3.88 (s, 3H), 3.61 (br, 2H). 13 C NMR (100 MHz, CDC13) δ 169.01, 163.62, 143.10, 141.23, 138.98, 136.87, 136.53, 133.26, 131.75, 128.74, 128.26, 128.06, 125.32, 124.67 ( 1 J CF = 241.3 Hz), 122.73, 53.88, 53.22, 26.16.

[0034] Compound II-1 : yellow solid, yield 67.8%; mp 205-207 °C. 1 H NMR (400 MHz, CDC13) δ 9.94 (s, 1H), 8.54 (d, J = 7.7 Hz, 1H), 8.43 (d, J = 7.4 Hz, 1H), 8.08 (d, J = 7.6 Hz, 1H), 7.80 (td, J = 7.6, 0.9 Hz, 1H), 7.56 - 7.50 (m, 2H), 7.45 (d, J = 7.6 Hz, 1H), 4.39 (br, 2H), 3.96 (s, 3H), 3.59 (br, 2H), 2.63 (s, 3H). 13 C NMR (100 MHz, CDC13) δ 169.41, 166.63, 143.28, 139.14, 136.78, 136.23, 133.39, 133.06, 132.35, 129.42, 128.86, 128.41, 127.88, 125.30, 53.26, 52.56, 25.90, 15.94.

[0035] Compound II-2: yellow solid, yield 83.1 %; mp 189-191 °C. 1 H NMR (400 MHz, CDC13) δ 9.77 (s, 1H), 8.63 (d, J = 6.0 Hz, 1H), 8.26 (s, 1H), 8.05 (d, J = 7.3 Hz, 1H), 7.95 (t, J = 7.3 Hz, 1H), 7.79 (t, J = 9.5 Hz, 1H), 7.64 (dd, J = 15.8, 7.7 Hz, 1H), 4.53 (t, J = 7.0 Hz, 2H), 3.92 (s, 2H), 3.43 (t, J = 7.3 Hz, 2H). 13 C NMR (150 MHz, DMSO-d6) δ 172.02, 164.79, 158.03( 1 J FC = 260.0), 139.69, 138.16, 135.80, 134.36( 3 J FC = 9.7), 118.60( 3 J FC = 11.3), 128.82( 2 J FC = 17.2), 128.88, 128.76, 127.60, 125.81, 118.60( 2 J FC = 20.1), 53.28, 52.11, 25.35.

[0036] Compound II-3: yellow solid, yield 58.4%; mp 177-179 °C. 1 H NMR (400 MHz, CDC13) δ 10.14 (s, 1H), 9.07 (d, J = 1.7 Hz, 1H), 8.43 (d, J = 7.5 Hz, 1H), 8.18 (dd, J = 8.4, 1.7 Hz, 1H), 7.81 (t, J = 7.3 Hz, 1H), 7.71 (d, J = 8.4 Hz, 1H), 7.54 (t, J = 7.6 Hz, 1H), 7.47 (d, J = 7.6 Hz, 1H), 4.45 (t, J = 7.3 Hz, 2H), 3.92 (s, 3H), 3.60 (t, J = 7.7 Hz, 2H). 13 C NMR (100 MHz, CDC13) δ 169.95, 164.63, 140.24, 139.44, 137.28, 136.53, 133.25, 133.05, 131.36, 131.20, 129.12, 128.53, 128.47, 125.73, 53.09, 53.02, 26.11.

[0037] Compound II-4: yellow solid, yield 68.1%; mp 191-193 °C. 1 H NMR (400 MHz, CDC13) δ 10.07 (s, 1H), 9.04 (d, J = 1.8 Hz, 1H), 8.40 (d, J = 7.6 Hz, 1H), 8.08 (dd, J = 8.4, 1.8 Hz, 1H), 7.85 (d, J = 8.4 Hz, 1H), 7.78 (t, J = 7.5 Hz, 1H), 7.52 (t, J = 7.6 Hz, 1H), 7.44 (d, J = 7.6 Hz, 1H), 4.41 (br, 2H), 3.90 (s, 3H), 3.60 (t, J = 7.8 Hz, 2H). 13 C NMR (100 MHz, CDC13) δ 169.60, 164.77, 141.96, 139.35, 137.31, 136.30, 134.34, 133.37, 132.18, 129.19, 128.50, 128.44, 125.83, 122.95, 53.15, 53.08, 26.22.

[0038] Compound II-5: yellow solid, yield 58.7%; mp 136-138 °C. 1H NMR (400 MHz, CDC13) δ 10.33 (s, 1H), 8.43 (d, J = 7.4 Hz, 1H), 8.36 (dd, J = 8.3, 2.7 Hz, 1H), 8.29 (d, J = 2.6 Hz, 1H), 7.74 (td, J = 7.6, 1.0 Hz, 1H), 7.52 - 7.36 (m, 3H), 4.61 (t, J = 7.9 Hz, 2H), 3.93 (s, 3H), 3.57 - 3.54 (m, 4H), 1.79 (dt, J = 14.4, 6.8 Hz, 2H), 1.49 (dq, J = 14.7, 7.4 Hz, 2H), 0.99 (t, J = 7.4 Hz, 3H). 13 C NMR (100 MHz, CDC13) δ 166.24, 166.02, 143.75, 140.07, 138.97, 136.73, 136.34, 134.08, 131.10, 128.87, 128.16, 126.45, 125.62, 124.08, 52.57, 51.71, 30.72, 26.23, 25.94, 19.32, 13.83.

[0039] Compound II-6: yellow solid, yield 84.7%; mp 178-180 °C. 1 H NMR (400 MHz, CDC13) δ 10.33 (s, 1H), 8.43 (d, J = 7.4 Hz, 1H), 8.36 (dd, J = 8.3, 2.7 Hz, 1H), 8.29 (d, J = 2.6 Hz, 1H), 7.74 (td, J = 7.6, 1.0 Hz, 1H), 7.52 - 7.36 (m, 3H), 4.61 (t, J = 7.9 Hz, 2H), 3.93 (s, 3H), 3.57 - 3.54 (m, 4H), 1.79 (dt, J = 14.4, 6.8 Hz, 2H), 1.49 (dq, J = 14.7, 7.4 Hz, 2H), 0.99 (t, J = 7.4 Hz, 3H). 13 C NMR (100 MHz, CDC13) δ 166.24, 166.02, 143.75, 140.07, 138.97, 136.73, 136.34, 134.08, 131.10, 128.87, 128.16, 126.45, 125.62, 124.08, 52.57, 51.71, 30.72, 26.23, 25.94, 19.32, 13.83.

[0040] Compound II-7: yellow solid, yield 81.4%; mp 176-178 °C. 1H NMR (400 MHz, DMSO-d6) δ 9.77 (s, 1H), 8.32 (s, 1H), 8.16 - 7.96 (m, 3H), 7.91 (t, J = 7.3 Hz, 1H), 7.65 - 7.60 (m, 2H), 4.58 (t, J = 7.0 Hz, 2H), 3.93 (s, 3H), 3.43 (t, J = 7.0 Hz, 2H). 13 C NMR (100 MHz, DMSO-d6) δ 168.61, 165.65, 142.54, 139.22, 139.20, 137.75, 135.86, 135.57, 134.12, 128.80, 127.70, 125.96, 125.85, 122.62, 53.57, 51.17, 25.30.

[0041] Compound III-1 : yellow solid, yield 61.2%; mp 185-187 °C. 1 H NMR (400 MHz, CDCl3) δ 10.15 (s, 1H), 8.42 (d, J = 7.5 Hz, 1H), 8.19 (d, J = 8.3 Hz, 1H), 8.03 (s, 1H), 7.96 (d, J = 8.2 Hz, 1H), 7.78 (t, J = 7.2 Hz, 1H), 7.49 - 7.49 (m, 7.6 Hz, 2H), 4.43 (t, J = 7.8 Hz, 2H), 3.95 (s, 3H), 3.58 (t, J = 7.8 Hz, 2H), 2.52 (s, 3H). 13 C NMR (100 MHz, CDCl3) δ 169.26, 165.53, 145.11, 139.29, 136.88, 136.40, 133.31, 132.43, 132.32, 129.26, 128.91, 128.43, 125.80, 125.25, 52.89, 52.68, 26.01, 18.30.

[0042] Compound III-2: yellow solid, yield 79.3%; mp 162-164 °C. 1 H NMR (400 MHz, CDCl3) δ 10.27 (s, 1H), 8.80 (t, J = 7.8 Hz, 1H), 8.44 (d, J = 7.5 Hz, 1H), 8.01 (d, J = 8.1 Hz, 1H), 7.94 (d, 3 J HFH NMR (400 MHz, CDC13) δ 10.06 (s, 1H), 8.87 (d, J = 8.3 Hz, 1H), 8.41 (d, J = 7.5 Hz, 1H), 8.23 (d, J = 1.6 Hz, 1H), 8.12 (dd, J = 8.3, 1.6 Hz, 1H), 7.81 (t, J = 7.5 Hz, 1H), 7.52 (t, J = 7.6 Hz, 1H), 7.45 (d, J = 7.6 Hz, 1H), 4.48 (t, J = 7.4 Hz, 2H), 3.98 (s, 3H), 3.60 (t, J = 7.8 Hz, 2H). 13 C NMR (100 MHz, CDC13) δ 169.78, 164.41, 143.20, 139.43, 137.31, 136.64, 133.96, 131.77, 130.30, 129.01, 128.46, 128.43, 125.66, 53.08, 52.94, 26.05. 1 J CF = 254.1 Hz), 139.43, 137.26, 136.79, 134.17 (d, J = 3.6 Hz), 131.74, 130.30, 129.10, 128.34, 127.71, 127.36, 125.98, 118.31, 118.11, 53.08, 52.79, 26.04. 2 J CF = 61.4 Hz), 129.10, 128.34, 127.71, 127.36, 125.98, 118.31, 118.11, 53.08, 52.79, 26.04.

[0043] Compound III-3: yellow solid, yield 64.1%; mp 192-194 °C. 1 H NMR (400 MHz, CDC13) δ 10.06 (s, 1H), 8.87 (d, J = 8.3 Hz, 1H), 8.41 (d, J = 7.5 Hz, 1H), 8.23 (d, J = 1.6 Hz, 1H), 8.12 (dd, J = 8.3, 1.6 Hz, 1H), 7.81 (t, J = 7.5 Hz, 1H), 7.52 (t, J = 7.6 Hz, 1H), 7.45 (d, J = 7.6 Hz, 1H), 4.48 (t, J = 7.4 Hz, 2H), 3.98 (s, 3H), 3.60 (t, J = 7.8 Hz, 2H). 13 C NMR (100 MHz, CDC13) δ 169.78, 164.41, 143.20, 139.43, 137.31, 136.64, 133.96, 131.77, 130.30, 129.01, 128.46, 128.43, 125.66, 53.08, 52.94, 26.05.

[0044] Compound III-4: yellow solid, yield 65.0%; mp 206-208 °C. 1H NMR (600 MHz, DMSO-d6) δ 9.78 (s, 1H), 8.41 (d, J = 1.3 Hz, 1H), 8.25 (dd, J = 8.2, 1.4 Hz, 1H), 8.16 (d, J = 8.2 Hz, 1H), 8.06 (d, J = 7.4 Hz, 1H), 7.98 (t, J = 7.4 Hz, 1H), 7.67 (t, J = 7.4 Hz, 2H), 4.47 (t, J = 7.5 Hz, 2H), 3.93 (s, 3H), 3.51 (t, J = 7.8 Hz, 2H). 13 C NMR (151 MHz, DMSO) δ 172.24, 164.55, 145.42, 140.14, 137.93, 136.02, 134.59, 133.74, 130.57, 129.24, 129.08, 128.60, 125.34, 118.68, 53.51, 52.45, 25.44.

[0045] Compound III-5: yellow solid, yield 73.3%; mp 192-194 °C. 1 H NMR (600 MHz, DMSO-d6) δ 9.78 (s, 1H), 8.41 (d, J = 1.3 Hz, 1H), 8.25 (dd, J = 8.2, 1.4 Hz, 1H), 8.16 (d, J = 8.2 Hz, 1H), 8.06 (d, J = 7.4 Hz, 1H), 7.98 (t, J = 7.4 Hz, 1H), 7.67 (t, J = 7.4 Hz, 2H), 4.47 (t, J = 7.5 Hz, 2H), 3.93 (s, 3H), 3.51 (t, J = 7.8 Hz, 2H). 13 C NMR (151 MHz, DMSO-d6) δ 168.14, 166.78, 145.31, 141.58, 139.19, 137.85, 135.61, 132.02, 131.80, 128.79, 126.09, 125.97, 120.75, 52.89, 50.93, 36.14, 25.30.

[0046] Compound III-6: yellow solid, yield 67.2%; mp 181-182 °C. 1 H NMR (600 MHz, DMSO-d6) δ 9.78 (s, 1H), 8.41 (d, J = 1.3 Hz, 1H), 8.25 (dd, J = 8.2, 1.4 Hz, 1H), 8.16 (d, J = 8.2 Hz, 1H), 8.06 (d, J = 7.4 Hz, 1H), 7.98 (t, J = 7.4 Hz, 1H), 7.67 (t, J = 7.4 Hz, 2H), 4.47 (t, J = 7.5 Hz, 2H), 3.93 (s, 3H), 3.51 (t, J = 7.8 Hz, 2H). 13CNMR (151 MHz, DMSO-d6) δ 169.16, 165.08, 145.81, 139.48, 137.98, 135.82, 133.23, 132.72, 132.19, 128.84, 125.87, 122.41, 53.50, 51.04, 25.27.

[0047] Compound III-7: yellow solid, yield 82.5%; mp 182-184°C. 1 H NMR (600 MHz, DMSO-d6) δ 9.78 (s, 1H), 8.38 (s, 1H), 7.95-7.92 (m, 2H), 6.82 (s, 1H), 6.72 (s, 1H), 4.59 (br, 2H), 3.91 (s, 6H), 3.51 (s, 3H), 3.42 (br, 2H). 13 C NMR (151 MHz, DMSO-d6) δ 169.17, 165.83, 145.61, 139.47, 137.94, 135.78, 135.71, 134.61, 132.35, 128.83, 128.67, 125.87, 122.83, 121.31, 56.10, 53.51, 51.07, 25.27.

[0048] Experimental method and results of anti-phytopathogenic fungi activity of target compounds I-III in Example 2.

[0049] The present application tested the in vitro activity of some target compounds I-III on six common crop pathogenic fungi, including Rhizotonia cerealis (RC), Physalospora piricola (PP), Fusarium graminearum (FG), Ustilago hordei (UH), Ustilago nuda (UN) and Alternaria alternata (AA), by mycelial growth rate method, with Quinclorac and Carbendazim as positive control drugs. The compounds were dissolved in dimethyl sulfoxide to prepare a stock solution with a concentration of 10 mg·L -1 , which was diluted with Tween solution to a test solution with a concentration of 50 mg·L -1 . 1 mL of the above solution was added to 9 mL of potato dextrose agar (PDA) medium, and the medium was completely solidified before the test fungi were inoculated. Dimethyl sulfoxide was used as a blank control, and the experiment was repeated three times. After 3-4 days of incubation at 25°C in the dark, the culture dishes were removed, and the colony diameters were measured by cross method. The results of the anti-phytopathogenic fungi test are shown in Table 2.

[0050] The results show that the 2-arylisoquinoline salt type compounds have moderate to significant in vitro fungistatic activity against six plant pathogenic fungi, which is equivalent to that of the commercial drugs chlorothalonil and boscalid. Therefore, the 2-arylisoquinoline salt type compounds of the present application can be used for preparing fungicides against plant pathogenic fungi.

[0051] Table 1 Structural formulas of target compounds I-III

[0052]

[0053]

[0054] Table 2 Anti-plant pathogenic fungal activity (50 mg·L-1, %) of target compounds I-III -1

[0055] ​

Claims

1. The application of a class of 2-arylisoquinoline salt compounds in the preparation of drugs against plant pathogenic fungi, wherein the plant pathogenic fungi are *Ustilago hordei*, *Ustilago nuda*, and *Alternaria alternata*, and the specific structural formula of the 2-arylisoquinoline salt compounds is as follows:

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