A coumarin derivative containing acylhydrazone sulfoxide, its synthesis method and application

Abstract

The present invention provides a coumarin derivative containing acylhydrazone sulfoxide, its synthesis method and application. The coumarin derivative containing acylhydrazone sulfoxide has a chemical structure as shown in Formula I. The synthesis route of the coumarin derivative containing acylhydrazone sulfoxide provided by the present invention can prepare the coumarin derivative containing acylhydrazone sulfoxide, which has excellent broad-spectrum antibacterial activity against phytopathogenic bacteria. Moreover, the raw materials for preparation are easily available, and the synthesis steps are simple and practical, providing a favorable lead compound for the creation of natural bionic antibacterial agents.

Description

Technical Field

[0001] The present invention relates to the technical field of the synthesis of coumarin derivatives, and particularly relates to a coumarin derivative containing acylhydrazone sulfoxide, a synthesis method thereof, and an application thereof. Background Art

[0002] The prevention and control of bacterial diseases of crops has always been a worldwide problem. Bacterial diseases caused by plant pathogenic bacteria cause a large reduction in crop yields, resulting in huge economic losses and seriously affecting the yield and quality of crops. At present, chemical control is the most effective method in production, but the number of existing bactericides does not meet the industrial demand. According to statistics, there are about 280 types of bactericides registered in China, accounting for only 2.6% of the total registered fungicides. The registered bactericides mainly include copper preparations, antibiotics, and thiazoles. Copper preparations are prone to phytotoxicity and excessive use is likely to cause a rampant mite infestation; thiazole agents have a great impact on non-target organisms; antibiotics are likely to cause environmental pollution. Therefore, it is imperative to develop new green, highly efficient, and low-risk bactericides with novel structures. Searching for lead compounds from natural products and designing and synthesizing natural bionic pesticides based on them is one of the effective ways to create new pesticides. Summary of the Invention

[0003] In view of this, in order to create a new type of green small molecule bactericide, the purpose of the present invention is to provide a coumarin derivative containing acylhydrazone sulfoxide, a synthesis method thereof, and an application thereof. The present invention designed and synthesized a series of novel coumarin-3-carboxylic acid compounds containing acylhydrazone sulfoxide groups, and found that the compounds of this skeleton not only have excellent broad-spectrum bactericidal activity against plant pathogenic bacteria, but also have easily available preparation raw materials and simple and practical synthesis steps, providing favorable lead compounds for the creation of natural bionic bactericides.

[0004] The technical solution of the present invention is realized as follows:

[0005] A coumarin derivative containing acylhydrazone sulfoxide, the coumarin derivative containing acylhydrazone sulfoxide has a chemical structure as shown in Formula I:

[0006]

[0007] In Formula I, R is selected from one of hydrogen, halogen, C1-C5 alkyl, C1-C2 haloalkyl, C1-C3 alkoxy, nitro, or cyano;

[0008] n is selected from 1-4;

[0009] R2 is selected from hydrogen, C1-C5 alkyl, C1-C2 haloalkyl, C2-C5 alkenyl, C2-C5 ester group, benzyl, or substituted benzyl.

[0010] Further, the halogen is selected from one of fluorine, chlorine, bromine or iodine;

[0011] The C1-C5 alkyl group is selected from one of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl or neopentyl;

[0012] The C1-C2 haloalkyl group is selected from one of trifluoromethane, difluorodichloromethane, trichloromethane, difluoromethane, dichloromethane, monofluoromethane, 1,2-difluoroethane, 1,2-methylfluoroethane, 1,2-dichloroethane or 1,2-tetrachloroethane;

[0013] The C1-C3 alkoxy group is selected from one of methoxy, ethoxy or n-propoxy;

[0014] The C2-C5 alkenyl group is selected from one of vinyl, propenyl, allyl, butenyl, isobutenyl, pentenyl, isopentenyl or neopentenyl;

[0015] The C2-C5 ester group is selected from one of methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate or propyl acetate;

[0016] The substituted benzyl group is selected from the group consisting of 4-methylbenzyl, 3-methylbenzyl, 2-methylbenzyl, 3,4-dimethylbenzyl, 2,4-dimethylbenzyl, 2,6-dimethylbenzyl, 4-fluorobenzyl, 3-fluorobenzyl, 2-fluorobenzyl, 3,4-difluorobenzyl, 2,4-difluorobenzyl, 2,6-difluorobenzyl, 4-chlorobenzyl, 3-chlorobenzyl, 2-chlorobenzyl, 3,4-dichlorobenzyl, 2,4-dichlorobenzyl, 2,6-dichlorobenzyl, 4-methoxybenzyl, 3-methoxybenzyl, 2-methoxybenzyl, 3,4-dimethoxybenzyl, 2,4-dimethoxybenzyl and 2,6-dimethoxybenzyl.

[0017] Furthermore, the present invention provides a method for synthesizing the above-mentioned coumarin derivatives containing acylhydrazone sulfoxide, comprising the following steps:

[0018] (1) Salicylaldehyde and diethyl malonate are used as raw materials, and piperidine is used for reflux reaction in an organic solvent, and the reaction is desolventized under reduced pressure and recrystallized to obtain coumarin-3-carboxylic acid ethyl ester;

[0019] (2) dissolving coumarin-3-carboxylic acid ethyl ester in an organic solvent, adding hydrazine hydrate, reacting at low temperature until completion, adding an extractant for extraction, drying, and desolventizing under reduced pressure to obtain coumarin-3-carboxylic acid hydrazone;

[0020] (3) taking coumarin-3-formylhydrazone, potassium hydroxide and carbon disulfide, adding an organic solvent, heating to a constant temperature for reaction, performing a reflux reaction, and filtering to obtain coumarin-3-formylhydrazone potassium dithioate;

[0021] (4) React coumarin-3-carbohydrazide dithioketone with halogenated hydrocarbon, precipitate solid, filter by suction, separate and purify to obtain coumarin-3-carbohydrazide-1-substituted dithioester;

[0022] (5) Dissolve coumarin-3-carbohydrazide-1-substituted dithioester in dichloromethane, add m-chloroperoxybenzoic acid for reaction. After the reaction ends, extract, wash, combine the organic layers, dry, remove the solvent under reduced pressure, separate and purify to obtain the coumarin derivative containing acylhydrazone sulfoxide.

[0023] Further, the preparation method of ethyl coumarin-3-carboxylate includes: dissolve salicylaldehyde and diethyl malonate in absolute ethanol under the catalysis of piperidine, heat under reflux for 10 - 14 h, cool, remove the solvent under pressure, add water and filter by suction, recrystallize to obtain ethyl coumarin-3-carboxylate;

[0024] The molar ratio of salicylaldehyde, diethyl malonate and piperidine is 1:1.2 - 1.3:0.2 - 0.3;

[0025] The preparation method of coumarin-3-carbohydrazide includes: dissolve ethyl coumarin-3-carboxylate in absolute ethanol, place it in a low-temperature constant-temperature stirring reaction bath, add hydrazine hydrate. After the reaction ends, add an extractant for extraction, dry, remove the solvent under reduced pressure to obtain coumarin-3-carbohydrazide;

[0026] The molar ratio of ethyl coumarin-3-carboxylate and hydrazine hydrate is 1:1.5 - 2.0;

[0027] The temperature of the low temperature is 0 - -5 °C;

[0028] The mass concentration of hydrazine hydrate is 80 - 85%;

[0029] The extractant is a mixed solution of dichloromethane and sodium chloride solution.

[0030] Further, the preparation method of coumarin-3-carbohydrazide dithioketone includes: add potassium hydroxide to absolute ethanol, after stirring until dissolved, add carbon disulfide, continue stirring until a pale yellow solid is formed, add coumarin-3-carbohydrazide, after heating and constant-temperature reaction, heat to the reflux temperature and continue the reaction for 10 - 12 h. After the reaction ends, filter by suction to obtain coumarin-3-carbohydrazide dithioketone;

[0031] The molar ratio of potassium hydroxide, carbon disulfide and coumarin-3-carbohydrazide is 1.1 - 1.3:1.4 - 1.6:1;

[0032] The conditions for the heating and constant-temperature reaction are: heat to a temperature of 40 - 45 °C and maintain the temperature at 40 - 45 °C for 2 - 2.5 h.

[0033] Furthermore, the preparation method of the coumarin-3-carbohydrazonyl-1-substituted dithioate includes: dissolving potassium coumarin-3-carbohydrazone dithiolate in N,N-dimethylformamide, adding potassium carbonate as an acid-binding agent, stirring, adding a halogenated hydrocarbon for reaction, after the reaction is completed, adding a saturated ammonium chloride aqueous solution, precipitating a solid, filtering by suction, separating and purifying to obtain coumarin-3-carbohydrazonyl-1-substituted dithioate;

[0034] The molar ratio of the potassium coumarin-3-carbohydrazone dithiolate, potassium carbonate and the halogenated hydrocarbon is 1:1.4 - 1.6:1.2 - 1.5.

[0035] Furthermore, the preparation method of the coumarin derivative containing acylhydrazone sulfoxide includes: dissolving the coumarin-3-carbohydrazonyl-1-substituted dithioate in dichloromethane, adding m-chloroperbenzoic acid for reaction, after the reaction is completed, extracting, washing, combining the organic layers, drying, evaporating under reduced pressure, separating and purifying to obtain the coumarin derivative containing acylhydrazone sulfoxide;

[0036] The molar ratio of the coumarin-3-carbohydrazonyl-1-substituted dithioate and m-chloroperbenzoic acid is 1:1.1 - 1.3.

[0037] Furthermore, the present invention also provides an application of the above-mentioned coumarin derivative containing acylhydrazone sulfoxide in inhibiting crop bacterial pathogens and / or preventing and controlling diseases caused by crop bacterial pathogens.

[0038] Furthermore, the bacterial pathogens include Xanthomonas, Pseudomonas, Pectobacterium, Ralstonia, Acidovorax, Dickeya, Clavibacter or Agrobacterium.

[0039] Furthermore, the diseases caused by the bacterial pathogens include the following:

[0040] Plant bacterial diseases caused by bacteria of the genus Xanthomonas include: rice bacterial blight, rice bacterial leaf streak, citrus canker, mango black spot, cotton angular leaf spot, cabbage black rot, pepper bacterial leaf spot or pepper scab;

[0041] Plant bacterial diseases caused by bacteria of the genus Pseudomonas include: rice bacterial brown spot, tomato bacterial speck, cucumber bacterial angular leaf spot or kiwifruit canker;

[0042] Plant bacterial diseases caused by bacteria of the genus Pectobacterium include: potato soft rot, Chinese cabbage soft rot or bacterial soft rot of solanaceous and cucurbitaceous crops;

[0043] Plant bacterial diseases caused by bacteria of the genus Ralstonia include: tobacco bacterial wilt, potato bacterial wilt, pepper bacterial wilt or tomato bacterial wilt;

[0044] Plant bacterial diseases caused by bacteria of the genus Acidiphilium include: bacterial fruit blotch of watermelon or bacterial fruit blotch of melon;

[0045] Plant bacterial diseases caused by bacteria of the genus Dickeya include: basal rot of rice or soft rot of banana;

[0046] Plant bacterial diseases caused by bacteria of the genus Clavibacter include: bacterial canker of tomato or ring rot of potato;

[0047] Plant bacterial diseases caused by bacteria of the genus Agrobacterium include: crown gall of fruit trees.

[0048] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0049] (1) The synthetic route of the coumarin derivatives containing acylhydrazone sulfoxide provided by the present invention, and the prepared coumarin derivatives containing acylhydrazone sulfoxide have high antibacterial activities against Xanthomonas oryzae pv. oryzae, Ralstonia solanacearum and Acidiphilium facilis, especially the compounds E1 and E2 provided by the present invention, whose antibacterial activities are better than those of the agricultural fungicide kasugamycin; in addition, for the compound E3 provided by the present invention, the bactericidal activity against Ralstonia solanacearum reaches more than 99.9%, and the effect is significantly better than that of the agricultural fungicide kasugamycin.

[0050] (2) For the compounds E1-E3 provided by the present invention, the EC 50 values against Xanthomonas oryzae pv. oryzae, Ralstonia solanacearum and Acidiphilium facilis are 2.97-4.49 μg / mL, 1.17-4.71 μg / mL and 1.23-7.30 μg / mL respectively.

[0051] (3) The pot experiment shows that the compound E2 provided by the present invention has excellent protective and therapeutic effects on bacterial wilt of tomato, and the effect is close to that of the agricultural fungicide kasugamycin.

[0052] (4) The synthetic route of the coumarin derivatives containing acylhydrazone sulfoxide provided by the present invention, and the prepared coumarin derivatives containing acylhydrazone sulfoxide have excellent broad-spectrum antibacterial activities against plant pathogenic bacteria, and the raw materials for preparation are easily available, and the synthesis steps are simple and practical, providing a favorable lead compound for the creation of natural bionic bactericides. Description of the Drawings

[0053] Figure 1 is the nuclear magnetic resonance hydrogen spectrum of the compound E1 of the present invention;

[0054] Figure 2 is the nuclear magnetic resonance carbon spectrum of the compound E1 of the present invention;

[0055] Figure 3Mass spectrum of Compound E1 of the present invention;

[0056] Figure 4 1H NMR spectrum of Compound E2 of the present invention;

[0057] Figure 5 13C NMR spectrum of Compound E2 of the present invention;

[0058] Figure 6 Mass spectrum of Compound E2 of the present invention;

[0059] Figure 7 1H NMR spectrum of Compound E3 of the present invention;

[0060] Figure 8 13C NMR spectrum of Compound E3 of the present invention;

[0061] Figure 9 Mass spectrum of Compound E3 of the present invention;

[0062] Figure 10 1H NMR spectrum of Compound E4 of the present invention;

[0063] Figure 11 1H NMR spectrum of Compound E5 of the present invention;

[0064] Figure 12 1H NMR spectrum of Compound E6 of the present invention;

[0065] Figure 13 1H NMR spectrum of Compound E7 of the present invention;

[0066] Figure 14 1H NMR spectrum of Compound E8 of the present invention;

[0067] Figure 15 1H NMR spectrum of Compound E9 of the present invention;

[0068] Figure 16 1H NMR spectrum of Compound E10 of the present invention;

[0069] Figure 17 1H NMR spectrum of Compound E11 of the present invention;

[0070] Figure 18 1H NMR spectrum of Compound E12 of the present invention;

[0071] Figure 19 1H NMR spectrum of Compound E13 of the present invention. Detailed implementation mode

[0072] To better understand the technical content of the present invention, specific embodiments are provided below to further illustrate the present invention.

[0073] Unless otherwise specified, the experimental methods used in the embodiments of the present invention are all conventional methods.

[0074] Unless otherwise specified, the materials, reagents, etc. used in the embodiments of the present invention can all be obtained from commercial channels.

[0075] Example 1 - Synthetic Route of Coumarin Derivatives Containing Acylhydrazone Sulfoxide

[0076] The synthetic route of coumarin derivatives containing acylhydrazone sulfoxide is as follows:

[0077]

[0078] Among them, the definitions of R, n, and R2 are as described below:

[0079] R is selected from hydrogen, halogen, C1-C5 alkyl, C1-C2 haloalkyl, C1-C3 alkoxy, nitro, or cyano;

[0080] n is selected from 1 - 4;

[0081] R2 is selected from hydrogen, C1-C5 alkyl, C1-C2 haloalkyl, C2-C5 alkenyl, C2-C5 ester group, benzyl, or substituted benzyl;

[0082] The halogen atom is fluorine, chlorine, bromine, or iodine, and the C1-C5 alkyl is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, or neopentyl;

[0083] The C1-C2 haloalkyl is trifluoromethyl, dichlorodifluoromethane, trichloromethane, difluoromethane, dichloromethane, fluoromethane, 1,2-difluoroethyl, 1,2-methfluoroethyl, 1,2-dichloroethyl, or 1,2-tetrachloroethyl;

[0084] The C1-C3 alkoxy is methoxy, ethoxy, or n-propoxy;

[0085] The C2-C5 alkenyl refers to vinyl, propenyl, allyl, butenyl, isobutenyl, pentenyl, isopentenyl, or neopentenyl;

[0086] The C2-C5 ester group is methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate or propyl acetate, and the substituted benzyl group is 4-methylbenzyl, 3-methylbenzyl, 2-methylbenzyl, 3,4-dimethylbenzyl, 2,4-dimethylbenzyl, 2,6-dimethylbenzyl, 4-fluorobenzyl, 3-fluorobenzyl, 2-fluorobenzyl, 3,4-difluorobenzyl, 2,4-difluorobenzyl, 2,6-difluorobenzyl, 4-chlorobenzyl, 3-chlorobenzyl, 2-chlorobenzyl, 3,4-dichlorobenzyl, 2,4-dichlorobenzyl, 2,6-dichlorobenzyl, 4-methoxybenzyl, 3-methoxybenzyl, 2-methoxybenzyl, 3,4-dimethoxybenzyl, 2,4-dimethoxybenzyl, 2,6-dimethoxybenzyl.

[0087] Preparation of Example 2-(E)-(methylsulfinyl)-N-coumaroylhydrazone thioate

[0088] (1) Preparation of ethyl coumarin-3-carboxylate intermediate

[0089] Salicylaldehyde (1.0 eq) and diethyl malonate (1.2 eq) were dissolved in absolute ethanol under the catalysis of piperidine (0.2 eq) and heated to reflux for 10 - 14 h. After cooling, part of the solvent was removed under reduced pressure, water was added and filtered by suction, and the intermediate ethyl coumarin-3-carboxylate was purified by recrystallization.

[0090] (2) Preparation of coumarin-3-carbohydrazone intermediate

[0091] The intermediate ethyl coumarin-3-carboxylate (1.0 eq) was added to a round-bottomed flask, dissolved in absolute ethanol, placed in a low-temperature constant-temperature stirring reaction bath, the temperature of the system was controlled below 0 - -5 °C, 80% hydrazine hydrate (1.5 - 2.0 eq) was added, and after monitoring by TLC until the reaction was complete, appropriate dichloromethane and saturated sodium chloride solution were added for extraction to obtain a dichloromethane solution containing the intermediate coumarin-3-carbohydrazone, which was dried with anhydrous sodium sulfate and the solvent was removed under reduced pressure to obtain the intermediate coumarin-3-carbohydrazone.

[0092] (3) Preparation of potassium coumarin-3-carbohydrazone dithiocarbonate intermediate

[0093] Potassium hydroxide (1.2 eq) was added to absolute ethanol, and after stirring until dissolved, carbon disulfide (1.5 eq) was added, and stirring was continued until a pale yellow solid was formed. Subsequently, the intermediate coumarin-3-carbohydrazone (1.0 eq) was added, heated to 40 °C, and the temperature was maintained for 2 h. Subsequently, it was heated to the reflux temperature and the reaction was continued for 10 - 12 h. Detection by TLC was carried out until the intermediate reaction was complete, and filtration by suction was carried out while it was hot to obtain the intermediate potassium coumarin-3-carbohydrazone dithiocarbonate.

[0094] (4) Preparation of Coumarin-3-carbohydrazonyl-1-substituted dithioesters

[0095] The intermediate potassium coumarin-3-carbohydrazone dithioate (1.0 eq) was dissolved in N,N-dimethylformamide (DMF), potassium carbonate (1.5 eq) was added as an acid-binding agent, and the mixture was stirred at room temperature for about 10 mins. Then various halogenated hydrocarbons (1.2 - 1.5 eq) were added, and the reaction was continued at room temperature for 5 - 10 h. After detecting the reaction completion by TLC, saturated ammonium chloride aqueous solution was added to the system. After the solid was precipitated, it was filtered by suction to obtain the crude product, which was separated and purified by recrystallization or column chromatography to obtain the target compound coumarin-3-carbohydrazonyl-1-substituted dithioesters.

[0096] (5) Preparation of (E)-(Methylsulfinyl)-N-coumarinylcarbohydrazonethioate

[0097] The target compound coumarin-3-carbohydrazonyl-1-substituted dithioesters (1.0 eq) was dissolved in dichloromethane, and m-chloroperoxybenzoic acid (1.2 eq) was added. The reaction was carried out for 10 - 30 mins. After detecting the reaction completion by TLC, extraction was carried out, and it was washed with saturated sodium chloride aqueous solution, saturated sodium bicarbonate aqueous solution and saturated sodium sulfite aqueous solution. The organic layers were combined, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to obtain the crude product of the target compound, which was separated and purified by recrystallization or column chromatography to obtain the target compound (E)-(methylsulfinyl)-N-coumarinylcarbohydrazonethioate.

[0098] Example 3 - Structural Characterization of Coumarin Derivatives Containing Hydrazone Sulfoxide

[0099] (E)-(Methylsulfinyl)-N-(2-oxo-2H-chromene-3-carbonyl)carbohydrazonethioate methyl ester (E1), yield: 38.65%, pale yellow solid, melting point: 171.5–172.9 °C. 1 H NMR(400MHz,CDCl3)δ12.41(s,H),9.06(s,H),7.77–7.72(m,2H),7.47–7.42(m,2H),2.83(s,3H)2.67(s,3H). 13 C NMR(101MHz,CDCl3)δ161.26,158.77,158.51,154.72,150.85,135.25,130.29,125.79,118.41,117.09,116.92,39.97,16.00.HRMS(ESI)m / z for C 13 H 12 N2O4NaS2[M+H] + calcd:347.01307,found:347.01239.

[0100] (E)-(Ethylsulfinyl)-N-(2-oxo-2H-chromene-3-carbonyl)carbohydrazonethioate (E2), Yield: 27.93%, Melting point: 168.5–169.0 °C. 1 H NMR (400 MHz, CDCl3) δ 12.58 (s, 1H), 9.08 (s, 1H), 7.79–7.74 (m, 2H), 7.50–7.42 (m, 2H), 3.39–3.30 (m, 1H), 3.23–3.01 (m, 3H), 1.42 (t, J = 7.4 Hz, 3H), 1.35 (t, J = 7.5 Hz, 3H). 13 C NMR (101 MHz, CDCl3) δ 161.19, 158.40, 157.63, 154.71, 150.81, 135.21, 130.27, 125.77, 118.41, 117.17, 116.90, 47.70, 28.99, 16.05, 6.89. HRMS (ESI) m / z for C 15 H 16 O4N2NaS2 [M + H] + calcd: 375.04437, found: 375.04309.

[0101] (E)-N-(2-Oxo-2H-chromene-3-carbonyl)(propylsulfinyl)carbohydrazonethioate propyl ester (E3), Yield: 25.16%, Pale yellow solid, Melting point: 167.0–169.3 °C. 1 H NMR (400 MHz, CDCl3) δ 14.28 (s, 1H), 8.97 (s, 1H), 7.74 (t, J = 7.8 Hz, 2H), 7.42 (t, J = 7.8 Hz, 2H), 3.57–3.50 (m, 1H), 3.46–3.39 (m, 2H), 3.37–3.29 (m, 1H), 2.30–2.19 (m, 1H), 2.01–1.95 (m, 2H), 1.94–1.89 (m, 1H), 1.18–1.11 (m, 6H). 13 C NMR (101 MHz, CDCl3) δ 159.95, 158.78, 155.00, 151.17, 146.94, 135.36, 130.31, 125.59, 118.26, 117.00, 55.99, 55.35, 16.41, 16.06, 13.04. HRMS (ESI) m / z for C 17 H 20 O4N2NaS2 [M + H] +calcd: 403..07567, found: 403.07449.

[0102] Isopropyl (E)-(isopropylsulfinyl)-N-(2-oxo-2H-chromene-3-carbonyl) carbazate thioate (E4), yield: 30.47%, pale yellow solid, melting point: 168.7–169.8 °C. 1 H NMR (400 MHz, CDCl3) δ 12.62 (s, 1H), 9.01 (s, 1H), 7.70 (dd, J = 15.8, 7.8 Hz, 2H), 7.4 (t, J = 7.8 Hz, 2H), 3.97–3.90 (m, 1H), 3.20–3.13 (m, 1H), 1.35 (t, J = 8.8 Hz, 6H), 1.28 (d, J = 6.8 Hz, 3H), 1.20 (d, J = 7.2 Hz, 3H). 13 C NMR (101 MHz, CDCl3) δ 161.13, 158.33, 157.27, 154.65, 150.83, 135.23, 130.29, 125.77, 118.37, 117.13, 116.82, 53.26, 41.23, 24.43, 24.11, 16.59, 14.80. HRMS (ESI) m / z for C 17 H 20 O4N2NaS2 [M + H] + calcd: 347.01307, found: 347.01239.

[0103] 2-Methylbenzyl (E)-((2-methylbenzyl)sulfinyl)-N-(2-oxo-2H-chromene-3-carbonyl) carbazate thioate (E5), yield: 18.84%, pale yellow solid, melting point: 183.6–185.1 °C. 1 H NMR (400 MHz, CDCl3) δ 12.18 (s, 1H), 8.89 (s, 1H), 7.70–7.65 (m, 2H), 7.41–7.34 (m, 2H), 7.20–7.18 (m, 2H), 7.13–7.12 (m, 3H), 7.09–6.96 (m, 4H), 4.41 (d, J = 12.0 Hz, 1H), 4.27–4.13 (m, 3H), 2.42 (s, 3H), 2.36 (s, 3H). 1313C NMR (101 MHz, CDCl3) δ 160.79, 158.10, 156.46, 154.73, 150.53, 137.96, 137.22, 135.14, 134.17, 131.56, 130.80, 130.66, 130.22, 130.17, 128.78, 128.40, 127.98, 126.40, 125.72, 118.38, 117.11, 116.90, 58.10, 37.55, 20.02, 19.29. HRMS (ESI) m / z for C 27 H 24 O4N2NaS2 [M+H] + calcd: 527.10697, found: 527.10565.

[0104] (E)-(Ethylsulfinyl)-N-(7-methoxy-2-oxo-2H-chromene-3-carbonyl)formohydrazonethioic acid ethyl ester (E6), Yield: 28.31%, pale yellow solid, Melting point: 176.2–177.7 °C. 1 1H NMR (400 MHz, CDCl3) δ 12.46 (s, 1H), 8.91 (s, 1H), 7.58 (d, J = 8.8 Hz, 1H), 6.92 (dd, J = 9.2, 2.4 Hz, 1H), 6.83 (d, J = 2.0 Hz, 1H), 3.88 (s, 3H), 3.22–3.15 (m, 1H), 3.05–2.96 (m, 2H), 2.88–2.83 (m, 1H), 1.80–1.64 (m, 4H), 1.02 (t, J = 7.4 Hz, 3H), 0.96 (t, J = 7.4 Hz, 3H). 13 13C NMR (101 MHz, CDCl3) δ 165.84, 161.55, 158.99, 157.36, 157.13, 150.57, 131.49, 114.60, 113.08, 112.29, 100.47, 56.23, 55.70, 36.22, 24.32, 16.24, 13.31, 13.10. HRMS (ESI) m / z for C 16 H 18 O5N2NaS2 [M+H] + calcd: 405.05493, found: 405.05411.

[0105] (E)-N-(7-Methoxy-2-oxo-2H-chromene-3-carbonyl)(propylsulfinyl)methoxy thiophosphate (E7), yield: 23.64%, light yellow solid, melting point: 161.7–163.2 °C. 1 H NMR (400 MHz, CDCl3) δ 12.46 (s, 1H), 8.91 (s, 1H), 7.58 (d, J = 8.8 Hz, 1H), 6.92 (dd, J = 8.8, 2.4 Hz, 1H), 6.83 (d, J = 2.0 Hz, 1H), 3.88 (s, 3H), 3.24–3.12 (m, 1H), 3.05–2.96 (m, 2H), 2.88–2.83 (m, 1H), 1.80–1.64 (m, 4H), 1.02 (t, J = 7.4 Hz, 3H), 0.96 (t, J = 7.4 Hz, 3H). 13 C NMR (101 MHz, CDCl3) δ 165.84, 161.55, 158.99, 157.36, 157.13, 150.57, 131.49, 114.60, 113.08, 112.29, 100.47, 56.23, 55.70, 36.22, 24.32, 16.24, 13.31, 13.10. HRMS (ESI) m / z for C 16 H 18 O5N2NaS2 [M + H] + calcd: 433.08623, found: 433.08560.

[0106] Isopropyl (E)-(isopropylsulfinyl)-N-(7-methoxy-2-oxo-2H-chromene-3-carbonyl) formylhydrazone thiocarboxylate (E8), yield: 39.72%, light yellow solid, melting point: 168.3–169.7 °C. 1 H NMR (400 MHz, CDCl3) δ 12.59 (s, 1H), 8.92 (s, 1H), 7.59 (d, J = 8.8 Hz, 1H), 6.92 (dd, J = 8.8, 2.4 Hz, 1H), 6.83 (d, J = 2.0 Hz, 1H), 3.97–3.88 (m, 1H), 3.88 (s, 3H), 3.19–3.12 (m, 1H), 1.35 (dd, J = 8.8, 6.4 Hz, 6H), 1.29 (d, J = 6.8 Hz, 3H), 1.19 (d, J = 6.8 Hz, 3H). 1313C NMR (101 MHz, CDCl3) δ 165.84, 161.57, 158.93, 157.15, 156.70, 150.60, 131.49, 114.59, 113.18, 112.31, 100.48, 56.23, 53.33, 41.15, 24.45, 24.12, 16.56, 14.92. HRMS (ESI) m / z for C 16 H 18 O5N2NaS2 [M+H] + calcd: 433.08623, found: 433.08548.

[0107] (E)-(Ethylsulfinyl)-N-(6-fluoro-2-oxo-2H-chromene-3-carbonyl)methanehydrazonothioate (E9), yield: 43.91%, pale yellow solid, melting point: 167.1–168.3 °C. 1 1H NMR (400 MHz, CDCl3) δ 12.46 (s, 1H), 8.96 (s, 1H), 7.40 (d, J = 6.4 Hz, 3H), 3.31–3.22 (m, 1H), 3.15–2.94 (m, 1H), 1.34 (t, J = 7.4 Hz, 3H), 1.28 (t, J = 7.4 Hz, 3H). 13 13C NMR (101 MHz, CDCl3) δ 160.79, 159.21 (d, J = 247.4 Hz), 158.14, 150.89, 149.78 (d, J = 3.1 Hz), 122.97, 122.72, 119.05 (d, J = 9.5 Hz), 118.67 (d, J = 8.5 Hz), 118.30, 115.10 (d, J = 24.0 Hz), 47.76, 29.03, 16.08, 6.88. HRMS (ESI) m / z for C 15 H 15 O4N2FNaS2 [M+H] + calcd: 393.03495, found: 393.03406.

[0108] (E)-N-(6-Fluoro-2-oxo-2H-chromene-3-carbonyl)(propylsulfinyl)formohydrazonothioate (E10), yield: 34.88%, pale yellow solid, melting point: 165.5–166.1 °C. 11H NMR (400 MHz, CDCl3) δ 12.45 (s, 1H), 8.96 (s, 1H), 7.40–7.38 (m, 3H), 3.26–3.19 (m, 1H), 3.08–2.99 (m, 2H), 2.91–2.84 (m, 1H), 1.80–1.66 (m, 4H), 1.04 (t, J = 7.4 Hz, 3H), 0.97 (t, J = 7.4 Hz, 3H). 13 13C NMR (101 MHz, CDCl3) δ 160.77, 159.22 (d, J = 244.9 Hz), 158.90, 150.91, 149.74 (d, J = 2.9 Hz), 122.95, 122.70, 119.06 (d, J = 9.4 Hz), 118.66 (d, J = 8.3 Hz), 118.32, 115.08 (d, J = 23.8 Hz), 55.87, 36.33, 24.38, 16.27, 13.32, 13.01. HRMS (ESI) m / z for C 17 H 19 O4N2FNaS2 [M + H] + calcd: 421.06625, found: 421.06543.

[0109] Isopropyl (E)-N-(6-fluoro-2-oxo-2H-chromene-3-carbonyl)(isopropylsulfinyl)methanethioate (E11), yield: 24.36%, pale yellow solid, melting point: 159.3–160.7 °C. 1 1H NMR (400 MHz, CDCl3) δ 14.30 (s, 1H), 8.83 (s, 1H), 7.37–7.32 (m, 3H), 3.75–3.68 (m, 1H), 3.35–3.29 (m, 1H), 1.55 (d, J = 6.8 Hz, 3H), 1.43 (dd, J = 8.0, 4.2 Hz, 6H), 1.36 (d, J = 7.2 Hz, 3H). 13 13C NMR (101 MHz, CDCl3) δ 160.76, 159.16 (d, J = 249.2 Hz), 150.87 (d, J = 1.6 Hz), 149.81 (d, J = 2.9 Hz), 122.95, 122.70, 119.06 (d, J = 9.3 Hz), 118.63 (d, J = 8.2 Hz), 118.31, 115.24, 115.01, 53.40, 41.36, 24.50, 24.10, 16.60, 14.79. HRMS (ESI) m / z for C 17 H 19O4N2FNaS2[M+H] + Calculated: 421.06625, Found: 421.06549.

[0110] (E)-N-(6-chloro-2-oxo-2H-chromene-3-carbonyl)(ethylsulfinyl)formohydrazonethioic acid ethyl ester (E12), Yield: 22.81%, pale yellow solid, Melting point: 156.3–157.0 °C. 1 H NMR (400 MHz, CDCl3) δ 12.42 (s, 1H), 8.93 (s, 1H), 7.68 (d, J = 2.4 Hz, 1H), 7.61 (dd, J = 8.8, 2.4 Hz, 1H), 7.35 (d, J = 9.2 Hz, 1H), 3.32–3.22 (m, 1H), 3.15–2.93 (m, 3H), 1.31 (dt, J = 23.6, 7.6 Hz, 6H). 13 C NMR (101 MHz, CDCl3) δ 160.61, 158.07, 157.91, 153.00, 149.50, 135.04, 131.19, 129.16, 119.33, 118.37, 118.31, 47.72, 29.02, 16.08, 6.86. HRMS (ESI) m / z for C 15 H 15 O4N2ClNaS2[M+H] + Calculated: 409.00540, Found: 409.00427.

[0111] (E)-N-(6-chloro-2-oxo-2H-chromene-3-carbonyl)(propylsulfinyl)methanethioate propyl ester (E13), Yield: 23.66%, pale yellow solid, Melting point: 154.2–156.1 °C. 1 H NMR (400 MHz, CDCl3) δ 12.52 (s, 1H), 9.02 (s, 1H), 7.76 (d, J = 1.6 Hz, 1H), 7.70 (d, J = 8.8 Hz, 1H), 7.44 (d, J = 8.8 Hz, 1H), 3.33–3.27 (m, 1H), 3.16–3.07 (m, 2H), 2.99–2.92 (m, 1H), 1.94–1.73 (m, 6H), 1.12 (t, J = 7.4 Hz, 3H),

[0112] 1.05 (t, J = 7.2 Hz, 3H). 13 C NMR (101 MHz, CDCl3) δ 160.60, 158.97, 157.94, 153.01, 149.47,

[0113] 135.03, 131.21, 129.14, 119.34, 118.37, 55.89, 36.36, 29.71, 24.40, 16.27, 13.33, 13.11. HRMS(ESI) m / z for C 17 H 19 O4N2ClNaS2 [M + H] + calcd: 437.03670, found: 437.03613.

[0114] Example 4 - Bactericidal Activity of Coumarin Derivatives Containing Acylhydrazone Sulfoxide

[0115] The turbidimetry method was used to test the in vitro activities of the synthesized target compounds E1 - E13 and the commercial control agent kasugamycin against three kinds of bacteria, namely Xanthomonas oryzae pv. oryzae, Ralstonia solanacearum, and Acidovorax citrulli. The test compounds were dissolved in DMSO to prepare a stock solution of 10000 μg / mL, and then diluted with liquid medium to prepare a drug - containing medium with a final concentration of 50 and 25 μg / mL. After adding 190 μL of the drug - containing medium to a 96 - well plate, 10 μL of a 0.6 A bacterial suspension was added. The treatment containing drug but no bacteria was used as the background control, kasugamycin was used as the positive agent control, the treatment without drug was used as the negative control, and 1% DMSO was used as the solvent control. After sealing the 96 - well plate with a sealing film, it was placed in a shaker at 180 rpm and 28 °C for cultivation. When the bacterial suspension in the negative control group became completely turbid after 12 h of cultivation, the OD600nm value of the bacterial suspension was measured with a fully automatic microplate reader, and the inhibition rate of each compound against the test strains was calculated. Each test treatment was repeated 3 times.

[0116] The increased value of light absorption ΔOD = OD600nm of the treatment - OD600nm of the background control (1)

[0117]

[0118] P is the inhibition rate, A0 is the increased value of the OD value of the negative control, and A1 is the increased value of the OD value of the compound.

[0119] Table 1 Bactericidal Activity of Target Compounds

[0120]

[0121]

[0122] Note: 3-CCA is Coumarin-3-carboxylic acid.

[0123] The bactericidal activities of coumarin derivatives containing acylhydrazone sulfoxide against Xanthomonas oryzae pv. oryzae, Ralstonia solanacearum, and Acidovorax avenae subsp. citrulli were tested. The results showed that at a test concentration of 50 μg / mL, the bactericidal activities of compounds E1 and E2 against Xanthomonas oryzae pv. oryzae, Ralstonia solanacearum, and Acidovorax avenae subsp. citrulli were 92.93%, 99.06%, 99.97% and 96.21%, 95.94%, 99.75% respectively. Their bactericidal activities were higher than that of the lead compound coumarin-3-carboxylic acid and showed no significant difference from the positive control agent kasugamycin. Compounds E6-E8 also had strong bactericidal activities and could effectively control Xanthomonas oryzae pv. oryzae, Ralstonia solanacearum, and Acidovorax avenae subsp. citrulli at a test concentration of 50 μg / mL, with the inhibition rates ranging from 60.10% to 98.55%. Compounds E9, E11, E12, and E13 obtained by modifying fluorine and chlorine at the 6-position of the coumarin benzene ring had strong selective antibacterial activities against Xanthomonas oryzae pv. oryzae, and the inhibition rates at a test concentration of 50 μg / mL were 71.82%, 86.48%, 92.69% and 80.61% respectively.

[0124] Example 5 - Toxicity determination of coumarin derivatives containing acylhydrazone sulfoxide against Xanthomonas oryzae pv. oryzae, Ralstonia solanacearum, and Acidovorax avenae subsp. citrulli

[0125] The test method was the same as that in Example 4. According to the preliminary test results, 5-7 concentrations were selected to test their toxicity against 3 plant pathogenic bacteria.

[0126] Table 2 EC 50 values

[0127]

[0128] Compound E2 had the highest bactericidal activities against Xanthomonas oryzae pv. oryzae, Ralstonia solanacearum, and Acidovorax avenae subsp. citrulli, and its EC 50 values were 2.97, 1.17, and 1.23 μg / mL respectively; other modified coumarin compounds also had certain bactericidal activities, and their EC 50 values against the three tested pathogens ranged from 3 to 8 μg / mL.

[0129] Example 6 - Pot experiment of compound E2 against Ralstonia solanacearum

[0130] (1) Seedling preparation: Tomato seeds (Zhongshu No. 4, provided by Zhongshu Seed Industry Technology (Beijing) Co., Ltd.) were soaked in hot water at 55 °C for 30 minutes for surface disinfection, then rinsed 3 times with sterilized distilled water, placed in an incubator at 28 °C for germination. After the seeds showed white tips, they were sown in plastic pots filled with planting soil and grown until the tomato plants had 4 - 5 true leaves for in vivo pot experiments.

[0131] (2) Inoculum preparation: Tomato bacterial wilt pathogen was inoculated onto TTC medium and cultured for 48 hours. Then, single colonies with strong virulence were picked out and transferred to 100 mL of LB medium, and then cultured at 28 °C and 180 rpm for 24 hours to obtain a bacterial suspension. Then, 10 mL of the stock suspension was added to 1 L of NB medium and cultured for another 24 hours. The bacterial cells were centrifuged at 4000 rpm for 15 minutes, and then adjusted to 1×10 8 CFU / mL with sterile distilled water.

[0132] (3) Experimental treatment: The tomato roots were damaged by cutting two or three times with a knife. Before or 24 hours after inoculation, 20 mL of different concentrations of the agent was poured into the soil around the tomato roots to evaluate the protective and therapeutic control effects. Each treatment was repeated 3 times, with 5 pots per repetition and 3 plants per pot. A 2% kasugamycin aqueous solution was used as the agent control, and deionized water without the agent was used as the blank control. The bacterial treatment without compound treatment was set as the negative control.

[0133] (4) Disease investigation: The disease incidence of tomato plants was investigated 21 days after the experimental treatment, and the disease incidence was observed and counted regularly.

[0134] Table 3 Disease severity grading standard for tomato bacterial wilt pathogen

[0135]

[0136] The formula for calculating the disease index of each treatment is:

[0137]

[0138] The formula for calculating the inhibition rate of each treatment is:

[0139]

[0140] Table 4 Protective and therapeutic effects of compound E2 against tomato bacterial wilt pathogen

[0141]

[0142]

[0143] The pot experiment results of compound E2 against Ralstonia solanacearum are shown in Table 4. The results indicate that compound E2 has excellent protective effects against tomato bacterial wilt (Table 4). When the tested concentration is 100 μg / mL, the protective efficacy is 63.90%, showing no significant difference from the control agent, 2% kasugamycin aqueous solution. Meanwhile, this compound also has strong therapeutic effects (55.55%) on tomato bacterial wilt.

[0144] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A coumarin derivative containing acylhydrazone sulfoxide, characterized in that, The coumarin derivative containing acylhydrazone sulfoxide has a chemical structure as shown in Formula I: In Formula I, R is selected from one of hydrogen, halogen, or C1-C3 alkoxy; n is selected from 1 - 4; R2 is selected from hydrogen, C1-C5 alkyl, C2-C5 alkenyl, or benzyl.

2. The coumarin derivative containing acylhydrazone sulfoxide according to claim 1, characterized in that, The halogen is selected from one of fluorine, chlorine, bromine, or iodine; The C1-C5 alkyl is selected from one of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, or neopentyl; The C1-C3 alkoxy is selected from one of methoxy, ethoxy, or n-propoxy; The C2-C5 alkenyl is selected from one of vinyl, propenyl, allyl, butenyl, isobutenyl, pentenyl, isopentenyl, or neopentenyl.

3. The synthesis method of the coumarin derivative containing acylhydrazone sulfoxide according to claim 1 or 2, characterized in that, It includes the following steps: (1) Using salicylaldehyde and diethyl malonate as raw materials, under the condition of an organic solvent, carrying out a piperidine-catalyzed reflux reaction, decompressing and desolvating, and recrystallizing to obtain ethyl coumarin-3-carboxylate; (2) Dissolving ethyl coumarin-3-carboxylate in an organic solvent, adding hydrazine hydrate, reacting until the end under low-temperature conditions, adding an extractant for extraction, drying, decompressing and desolvating to obtain coumarin-3-carbohydrazide; (3) Taking coumarin-3-carbohydrazide, potassium hydroxide, and carbon disulfide, adding an organic solvent, heating and reacting at a constant temperature, then carrying out a reflux reaction, filtering by suction to obtain potassium dithiocarbonate of coumarin-3-carbohydrazide; (4) Reacting potassium dithiocarbonate of coumarin-3-carbohydrazide with a halogenated hydrocarbon, precipitating a solid, filtering by suction, separating and purifying to obtain coumarin-3-carbohydrazide-1-substituted dithioester; (5) Dissolving coumarin-3-carbohydrazide-1-substituted dithioester in dichloromethane, adding m-chloroperoxybenzoic acid for reaction, after the reaction ends, extracting, washing, combining the organic layers, drying, decompressing and desolvating, separating and purifying to obtain the coumarin derivative containing acylhydrazone sulfoxide.

4. The synthesis method of the coumarin derivative containing acylhydrazone sulfoxide according to claim 3, characterized in that, The preparation method of the ethyl coumarin-3-carboxylate includes: dissolving salicylaldehyde and diethyl malonate in anhydrous ethanol under the catalysis of piperidine, carrying out heating reflux for 10 - 14 h, cooling, decompressing and desolvating, adding water and filtering by suction, and recrystallizing to obtain ethyl coumarin-3-carboxylate; The molar ratio of salicylaldehyde, diethyl malonate, and piperidine is 1:1.2 - 1.3:0.2 - 0.3; The preparation method of the coumarin-3-carbohydrazide includes: dissolving ethyl coumarin-3-carboxylate in anhydrous ethanol, placing it in a low-temperature constant-temperature stirring reaction bath, adding hydrazine hydrate, after the reaction ends, adding an extractant for extraction, drying, decompressing and desolvating to obtain coumarin-3-carbohydrazide; The molar ratio of ethyl coumarin-3-carboxylate and hydrazine hydrate is 1:1.5 - 2.0; The temperature of the low temperature is 0 - -5°C; The mass concentration of the hydrazine hydrate is 80 - 85%; The extractant is a mixed solution of dichloromethane and sodium chloride solution.

5. The synthesis method of the coumarin derivative containing acylhydrazone sulfoxide according to claim 3, characterized in that, The preparation method of potassium coumarin-3-carbohydrazone dithiocarbonate includes: adding potassium hydroxide into absolute ethanol, adding carbon disulfide after stirring until dissolved, continuing to stir until a pale yellow solid is formed, adding coumarin-3-carbohydrazone, reacting at a constant temperature after heating, heating to the reflux temperature and continuing to react for 10-12 h. After the reaction is completed, perform suction filtration to obtain potassium coumarin-3-carbohydrazone dithiocarbonate; The molar ratio of the potassium hydroxide, carbon disulfide and coumarin-3-carbohydrazone is 1.1-1.3:1.4-1.6:1; The conditions for the constant temperature reaction by heating are: heating to a temperature of 40-45 °C and maintaining the temperature at 40-45 °C for reaction for 2-2.5 h.

6. The synthesis method of the coumarin derivative containing acylhydrazone sulfoxide according to claim 3, characterized in that, The preparation method of coumarin-3-carbohydrazone-1-substituted dithioester includes: dissolving potassium coumarin-3-carbohydrazone dithiocarbonate in N,N-dimethylformamide, adding potassium carbonate as an acid-binding agent, stirring, adding a halogenated hydrocarbon for reaction. After the reaction is completed, add a saturated ammonium chloride aqueous solution, precipitate a solid, perform suction filtration, separate and purify to obtain coumarin-3-carbohydrazone-1-substituted dithioester; The molar ratio of the potassium coumarin-3-carbohydrazone dithiocarbonate, potassium carbonate and the halogenated hydrocarbon is 1:1.4-1.6:1.2-1.

5.

7. The synthesis method of the coumarin derivative containing acylhydrazone sulfoxide according to claim 3, characterized in that The preparation method of the coumarin derivative containing acylhydrazone sulfoxide includes: dissolving the coumarin-3-carbohydrazone-1-substituted dithioester in dichloromethane, adding m-chloroperbenzoic acid for reaction. After the reaction is completed, perform extraction, washing, combine the organic layers, dry, remove the solvent under reduced pressure, separate and purify to obtain the coumarin derivative containing acylhydrazone sulfoxide; The molar ratio of the coumarin-3-carbohydrazone-1-substituted dithioester and m-chloroperbenzoic acid is 1:1.1-1.

3.

8. Use of the coumarin derivative containing acylhydrazone sulfoxide according to claim 1 or 2, characterized in that, The application of the coumarin derivative containing acylhydrazone sulfoxide in inhibiting crop bacterial pathogens and / or preventing diseases caused by crop bacterial pathogens. The diseases caused by the bacterial pathogens are as follows: The plant bacterial diseases caused by bacteria of the genus Xanthomonas are: rice bacterial blight; The plant bacterial diseases caused by bacteria of the genus Ralstonia are: tobacco bacterial wilt, potato bacterial wilt, pepper bacterial wilt or tomato bacterial wilt; The plant bacterial diseases caused by bacteria of the genus Acidovorax are: watermelon bacterial fruit blotch or melon bacterial fruit blotch.

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