Benzα-pyrone derivatives, process for their preparation and use thereof

Abstract

The application discloses a benzene-alpha-pyrone derivative, a preparation method and application thereof. The benzene-alpha-pyrone derivative is selected from a compound shown in a formula (A-A); wherein R1 is selected from a group shown in the formula, H or C1-C10 alkyl, wherein R 1′ is selected from a substituted or unsubstituted aryl, R 1″ is selected from H or C1-C10 ester group; R2 is selected from a group shown in the formula, H or hydroxyl, wherein R 2′ is selected from a substituted or unsubstituted heteroaryl, a substituted or unsubstituted aryl; R3 is selected from H, a substituted or unsubstituted C1-C10 alkyl; R4 is selected from a group shown in the formula or H, wherein R 4′ is selected from a substituted or unsubstituted aryl, alkoxy. The benzene-alpha-pyrone derivative has simple structure, small molecular weight and good biological activity, can inhibit the tested bacteria in different degrees, and can be used as a potential new antibacterial agent.

Description

Technical Field

[0001] This invention relates to the technical field of plant antibacterial agents, and more specifically, to benzo-α-pyranone derivatives, their preparation methods, and applications. Background Technology

[0002] Using natural active products as lead compounds and modifying their structures to obtain substances with superior properties has become a research hotspot worldwide. Coumarin, scientifically known as benzo-α-pyranone, is an oxygen-containing heterocyclic compound. Coumarin and its derivatives are widely distributed in nature, existing as secondary metabolites in the roots, flowers, leaves, bark, seeds, and fruits of many plants. These compounds possess advantages such as small molecular weight, relatively simple synthesis, broad pharmacological effects, and low toxicity, attracting widespread attention from scholars both domestically and internationally.

[0003] Many reported coumarin-based natural and synthetic compounds possess a wide range of pharmacological activities, such as antibacterial, antioxidant, anticancer, antituberculosis, antiproliferative, and enzyme-inhibiting activities. Currently, drugs containing effective coumarin derivatives are available on the market, such as leucin (antibiotic), warfarin (anticoagulant), phenylpropanol (anticoagulant), cyclosporine (anticholinergic and anticonvulsant), and methoxsalen (anti-psoriasis).

[0004] Plant diseases are a global threat to crop growth and the ecological environment. Crops are susceptible to many fungal infections, leading to reduced yields and significant economic losses. Therefore, developing new antifungal drugs is one way to address this problem and improve crop productivity. To date, no reports have been published regarding coumarin compounds identical to those in this patent and their antifungal applications against plant-derived fungi. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention proposes benzo-α-pyranone derivatives, their preparation methods, and applications. The benzo-α-pyranone derivatives of this invention have simple structures and small molecular weights; they possess good biological activity, exhibiting varying degrees of inhibition against all tested bacteria, and can serve as potential novel antibacterial agents.

[0006] One object of the present invention is to provide a benzo-α-pyranone derivative, wherein the benzo-α-pyranone derivative is selected from compounds represented by formula (AA);

[0007]

[0008] Wherein, R1 is selected from The indicated group, H or C1-C10 alkyl, wherein R 1′ Selected from substituted or unsubstituted aryl groups, R1″ Selected from H or C1-C10 ester groups;

[0009] R2 is selected from The indicated group, H or hydroxyl group, wherein R2′ is selected from substituted or unsubstituted heteroaryl, substituted or unsubstituted aryl;

[0010] The R3 is selected from H, substituted or unsubstituted C1-C10 alkyl groups;

[0011] R4 is selected from The indicated group or H, wherein R4′ is selected from substituted or unsubstituted aryl or alkoxy groups.

[0012] In the benzo-α-pyranone derivatives described in this invention, preferably:

[0013] R1 is selected from The indicated group or C1-C5 alkyl group, wherein R1′ is selected from substituted or unsubstituted phenyl groups, R 1″ Selected from H or C1-C5 ester groups; and / or,

[0014] R2 is selected from The group shown, wherein R 2′ Selected from substituted or unsubstituted indolyl groups of C8-C14, substituted or unsubstituted phenyl groups of C6-C10; and / or,

[0015] The R3 is selected from H, substituted or unsubstituted C1-C5 alkyl groups; and / or

[0016] R4 is selected from The group shown, wherein R 4′ Selected from substituted or unsubstituted phenyl, C1-C10 alkoxy groups.

[0017] In the benzo-α-pyranone derivatives described in this invention, preferably:

[0018] R1 is selected from The indicated group or C1-C3 alkyl group, wherein R 1′ Selected from phenyl, alkoxy and / or hydroxy-substituted phenyl groups, R 1″ Selected from H or C1-C4 ester groups; and / or,

[0019] R2 is selected from The group shown, wherein R 2′ Selected from C8-C10 substituted or unsubstituted indolyl, hydroxyl, and / or C1-C5 alkyl-substituted phenyl groups; and / or,

[0020] The R3 is selected from substituted or unsubstituted C1-C3 alkyl groups; and / or,

[0021] R4 is selected from The group shown, wherein R 4′ Selected from phenyl, C1-C5 alkyl-substituted phenyl, and C1-C5 alkoxy.

[0022] In the benzo-α-pyranone derivatives described in this invention, preferably:

[0023] R1 is selected from The indicated group or C1-C2 alkyl group, wherein R 1′ Selected from phenyl, C1-C5 alkoxy-substituted and hydroxyl-substituted phenyl groups, preferably with the C1-C5 alkoxy and hydroxyl groups in the ortho position on the benzene ring, R 1″ Selected from H or C1-C3 straight-chain ester groups; and / or,

[0024] R2 is selected from The group shown, wherein R 2′ Selected from indole, hydroxyl, and / or C1-C3 alkyl-substituted phenyl groups; and / or,

[0025] The R3 is selected from substituted or unsubstituted C1-C2 alkyl groups; and / or,

[0026] R4 is selected from The group shown, wherein R 4′ Selected from C1-C3 alkyl-substituted phenyl C1-C3 straight-chain alkoxy groups.

[0027] In the benzo-α-pyranone derivatives described in this invention, preferably:

[0028] The benzo-α-pyranone derivatives are selected from compounds represented by formula (I), formula (II), and formula (III);

[0029]

[0030] Among them, R1, R 1′ R 1″ R 2′ R3, R 4′ R1, R2 of any of the benzo-α-pyranone derivatives described above in this invention 1′ R 1″ R 2′ R3, R 4′ The correspondence is the same.

[0031] This invention relates to a class of compounds called Schiff bases, which are obtained by condensing primary amine compounds with simple aldehydes and ketones. These compounds contain an imine group (-RC=N-) in their molecular structure. The presence of the imine in the Schiff base structure gives them high biological activity, including antiviral and antibacterial activities. Furthermore, by combining these with other substituents on the coumarin backbone, a series of compounds with potentially superior biological activity and properties can be obtained.

[0032] In the benzo-α-pyranone derivatives described in this invention, preferably:

[0033] The benzo-α-pyranone derivatives are selected from the compounds shown below;

[0034]

[0035]

[0036] A second objective of this invention is to provide a method for preparing the benzo-α-pyranone derivatives described in one objective of this invention, wherein the derivative is selected from at least one of the following methods:

[0037] Method (1): The compound shown in formula A and R 4′ -NH2·HCl, a weak base or a weak acid, react in a solvent upon heating to produce a compound of formula (AA);

[0038] The structure of the compound shown in Formula A is as follows:

[0039]

[0040] R 4′ R in -NH2·HCl 4′ R in any of the benzo-α-pyranone derivatives described above in this invention 4′ The corresponding ones are the same;

[0041] Method (2): The compound shown in formula D, The compound is reacted by heating with either p-toluenesulfonic acid or glacial acetic acid, optionally in a solvent, to produce the compound shown in formula (AA).

[0042] The structure of the compound shown in formula D is as follows:

[0043]

[0044] R in 1′、 R 1″ R in any of the benzo-α-pyranone derivatives described above in this invention 1′、 R 1″ The corresponding ones are the same;

[0045] R3 in the compound shown in Formula D corresponds to the same R3 in the benzo-α-pyranone derivatives described in any of the above claims of the present invention;

[0046] Method (3): Compounds shown in Formula F, An organic weak acid reacts with heat in a solvent to produce a compound shown in formula (AA);

[0047] The structure of the compound shown in formula F is as follows:

[0048]

[0049] Wherein R1 corresponds to the same R1 in any of the benzo-α-pyranone derivatives described above in this invention; preferably, R1 is methyl.

[0050] R in 2′ R in any of the benzo-α-pyranone derivatives described above in this invention 2’ The correspondence is the same.

[0051] In the preparation method of benzo-α-pyranone derivatives described in this invention, preferably,

[0052] In method (1), the solvent is selected from methanol or ethanol; and / or,

[0053] The weak base is selected from at least one of pyridine or triethylamine; the weak acid is selected from glacial acetic acid; and / or,

[0054] The heating temperature is 75-100℃; and / or,

[0055] The heating time is 3-6 hours; and / or,

[0056] The compound shown in Formula A and R 4′ The molar ratio of -NH2·HCl is 1:(0.8~1.4); and / or,

[0057] The molar volume ratio of the compound shown in Formula A to the solvent is 1 mmol:(5–8) mL; and / or,

[0058] When reacting with a weak base, the molar ratio of the compound shown in Formula A to the weak base is 1:(1–1.35); or,

[0059] When reacting with a weak acid, the molar volume ratio of the compound shown in Formula A to the weak acid is 1 mmol:(1-3) mL.

[0060] In the preparation method of benzo-α-pyranone derivatives described in this invention, preferably,

[0061] In method (2), when reacting with p-toluenesulfonic acid, the following steps are included:

[0062] Will Grind and mix p-toluenesulfonic acid until homogeneous, add the compound shown in formula D and continue grinding. After thorough grinding, heat to react and generate the compound shown in formula (AA).

[0063] Preferably,

[0064] The molar ratio of the compound to that shown in formula D is 1:(0.9-1.2); and / or,

[0065] The molar ratio of the compound shown in Formula D to p-toluenesulfonic acid is 1:(0.15-0.4); and / or,

[0066] The temperature of the heating reaction is 60-100℃; and / or,

[0067] The heating reaction time is 3-6 hours; and / or,

[0068] In method (2), when reacting with glacial acetic acid, the following steps are included:

[0069] The compound shown in formula D, A mixture of solvent and glacial acetic acid was heated to produce a compound shown in formula (AA).

[0070] Preferably,

[0071] The molar ratio of the compound to that shown in formula D is 1:(0.6-1.2); and / or,

[0072] The molar volume ratio of acetic acid to glacial acetic acid is 1 mmol:(1–3) mL; and / or,

[0073] The molar volume ratio of the solvent to the solvent is 1 mmol:(4–8) mL; and / or,

[0074] The solvent is selected from ethanol; and / or,

[0075] The temperature for heating the reaction is 60-100℃; and / or,

[0076] The heating reaction time is 5-10 hours.

[0077] In the preparation method of benzo-α-pyranone derivatives described in this invention, preferably,

[0078] In method (3),

[0079] The solvent is selected from methanol or ethanol; and / or,

[0080] The weak organic acid is selected from glacial acetic acid; and / or,

[0081] The temperature of the heating reaction is 60-100℃; and / or,

[0082] The heating reaction time is 5-10 hours; and / or,

[0083] The compound shown in formula F and The molar ratio is (0.7-1):1; and / or,

[0084] The molar volume ratio with the weak organic acid is 1 mmol:(1–3) mL; and / or,

[0085] The molar volume ratio of the solvent to the solvent is 1 mmol:(4-8) mL.

[0086] A third objective of this invention is to provide the application of benzo-α-pyranone derivatives as described in one objective of this invention or benzo-α-pyranone derivatives prepared by the preparation method described in another objective of this invention in antibacterial agents; preferably, in antibacterial agents for at least one of the following pathogens: Botrytis cinerea, Alternaria alternata, Fusarium oxysporum, and Alternaria alternata.

[0087] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values; these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In the following, various technical solutions can, in principle, be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.

[0088] Compared with the prior art, the present invention has at least the following advantages:

[0089] (1) The present invention establishes a method for synthesizing benzo-α-pyranone derivatives and identifies their structures; the benzo-α-pyranone derivatives of the present invention have simple structures and small molecular weights; they have good biological activity and inhibit the test bacteria to varying degrees, and can be used as potential new antibacterial agents.

[0090] (2) The synthesis method of the present invention is simple and has few steps, and has high separation. Detailed Implementation

[0091] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0092] It should also be noted that the various specific technical features described in the following embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the various possible combinations will not be described separately in this invention.

[0093] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention. The resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0094] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0095] Example 1

[0096] 1. Synthesis of 6-aldehyde coumarin (the structure of this compound is known).

[0097]

[0098] Under oil bath conditions at 110°C, using dichloroethane as a solvent, palladium acetate (0.05 mmol, 11.2 mg), 1,10-phenanthroline monohydrate (0.1 mmol, 20 mg), copper acetate monohydrate (0.5 mmol, 100 mg), sodium acetate (1.5 mmol, 123 mg), and a molecular sieve were added to a 25 ml round-bottom flask. The reaction mixture consisted of 130 mg of p-hydroxybenzaldehyde (1 mmol, 122.1 mg) and methyl acrylate (0.5 mmol, 45.3 μL). The mixture was refluxed for 24 h. After the reaction, the reaction mixture was filtered through diatomaceous earth using ethyl acetate as a washing agent. The resulting ethyl acetate layer was washed with a brine solution, dried over anhydrous sodium sulfate, and evaporated under reduced pressure. Column chromatography was performed using petroleum ether / ethyl acetate = 4:1 as the eluent, and the residue was purified. The yield of the target product was 71% (61 mg), with a melting range of 190-192 °C.

[0099] 2. Synthesis of compound 1

[0100]

[0101] Under oil bath conditions at 80°C, 6-aldehyde coumarin (130.5 mg, 0.75 mmol), methoxyamine hydrochloride (75 mg, 0.9 mmol), and pyridine (79 mg, 1 mmol) were sequentially added to a 25 mL round-bottom flask equipped with a stirrer and a condenser, using methanol as the solvent (5 mL). The reaction was stopped after 3 hours. After standing for half an hour, recrystallization yielded compound 1. The yield of the target product was 65.7% (98.6 mg), with a melting range of 130-132°C.

[0102] Example 2

[0103] Synthesized compound 2:

[0104]

[0105] Under 80°C oil bath conditions, 6-aldehyde coumarin (87 mg, 0.5 mmol), 2,6-dimethylaniline hydrochloride (70 mg, 0.45 mmol), and one drop of glacial acetic acid (1 mL) were sequentially added to a 25 mL round-bottom flask equipped with a stirrer and condenser. Anhydrous ethanol (5 mL) was used as the solvent, and the reaction was stopped after 6 h. After the reaction was completed, the product was purified by column chromatography using dichloromethane:ethyl acetate (30:1) as the eluent to obtain compound 2. The yield of the target product was 28.9% (40 mg).

[0106] Example 3

[0107] 1. Synthesis of 7-hydroxy-4-aminocoumarin (the structure of this compound is known).

[0108]

[0109] At room temperature, resorcinol (22.84 g, 0.2 mol), cyanoacetic acid (19.33 g, 0.2 mol), zinc chloride (13.95 g, 0.1 mmol), and diethyl ether (50 mL) were added sequentially to a dry three-necked round-bottom flask. A condenser and a drying tube containing anhydrous calcium chloride were attached. Hydrogen chloride gas and nitrogen gas were continuously introduced, and the reaction was stirred vigorously for 5 hours. After that, a large amount of white solid precipitate appeared in the three-necked round-bottom flask. The reaction was stopped, quenched with distilled water, and the white solid was filtered and dried. The yield of the target product was 23.7% (8.41 g), and the melting range was 272.2-273 °C.

[0110] 2. Synthesis of compound 3:

[0111]

[0112] Methyl benzoylformate (164 mg, 1 mmol) was placed in a mortar, and p-toluenesulfonic acid (34.3 mg, 0.2 mmol) was added. The mixture was ground and mixed thoroughly, and then 4-amino-7-hydroxycoumarin (178 mg, 1 mmol) was added. After thorough grinding, the mixture was heated at 80 °C for 4 h. After the reaction was completed, the mixture was washed with ethyl acetate and filtered. The product was purified by column chromatography using dichloromethane:methanol = 30:1 as the eluent to obtain compound 3. The yield of the target product was 38.56% (130.07 mg). The melting range was 267-270 °C.

[0113] Example 4

[0114] 1. Synthesis of 7-hydroxy-4-amino-8-methylcoumarin (the structure of this compound is known).

[0115]

[0116] At room temperature, 12.7504 g (0.1 mol) of 2-methyl-1,3-benzenediphenol, 8.683 g (0.1 mol) of cyanoacetic acid, 7.168 g (0.05 mmol) of zinc chloride, and 50 ml of diethyl ether were added sequentially to a dry three-necked round-bottom flask. Hydrogen chloride and nitrogen gases were continuously introduced, and the reaction was stirred vigorously for 5 hours. A large amount of white solid precipitate appeared in the flask. The reaction was stopped, quenched with distilled water, and the white solid was filtered and dried. The yield of the target product was 39.87% (7.616 g). The melting range was 292.2℃–295℃.

[0117] 2. Synthesis of compound 4

[0118]

[0119] Methyl benzoylformate (164 mg, 1 mmol) was placed in a mortar, and p-toluenesulfonic acid (34.3 mg, 0.2 mmol) was added. The mixture was ground until homogeneous, and then 4-amino-7-hydroxy-8-methylcoumarin (193 mg, 1 mmol) was added. After thorough grinding, the mixture was heated at 80 °C for 4 h. After the reaction was complete, the mixture was washed with ethyl acetate and filtered. The product was purified by column chromatography using dichloromethane:methanol = 30:1 as the eluent to obtain compound 4. The yield of the target product was 35.6% (120.1 mg). The melting range was 283-285 °C.

[0120] Example 5

[0121] Synthesized compound 5:

[0122]

[0123] Under oil bath conditions at 80°C, 4-amino-7-hydroxy-8-methylcoumarin (144 mg, 0.75 mmol), vanillin (152 mg, 1 mmol), and glacial acetic acid (2 mL) were sequentially added to a 25 mL round-bottom flask equipped with a stirrer and a condenser. Anhydrous ethanol (5 mL) was used as the solvent, and the reaction was stopped after 8 hours. Solid was observed to be drawn out. The reaction mixture was filtered using methanol as a washing agent to give compound 5. The yield of the target product was 33.03% (80.6 mg). The melting range was 258°C–260°C.

[0124] Example 6

[0125] Synthetic compound 6

[0126]

[0127] 7-Amino-4-methylcoumarin (131 mg, 0.75 mmol), indole-3-carboxaldehyde (145 mg, 1 mmol), and glacial acetic acid (2 mL) were sequentially added to a 25 mL round-bottom flask equipped with a stirrer and a condenser, using anhydrous ethanol (5 mL) as solvent. The reaction was stopped after 8 hours. Solid was observed to be drawn out. The reaction mixture was filtered using methanol as a washing agent to give compound 6. The yield of the target product was 40.17% (91 mg). The melting range was 264-265 °C.

[0128] Example 7

[0129]

[0130] Under oil bath conditions at 80°C, 7-amino-4-methylcoumarin (131 mg, 0.75 mmol), 2,4-dihydroxybenzaldehyde (138 mg, 1 mmol), and glacial acetic acid (2 mL) were sequentially added to a 25 mL round-bottom flask equipped with a stirrer and a condenser. Anhydrous ethanol (5 mL) was used as the solvent, and the reaction was stopped after 8 hours. Solid was observed to be drawn out. The reaction mixture was filtered using methanol as a washing agent to obtain compound 7. The yield of the target product was 64.7% (143.3 mg). The melting range was 226-228°C.

[0131] Example 8

[0132]

[0133] 7-Amino-4-methylcoumarin (131 mg, 0.75 mmol), 2,4-dihydroxy-3-methylbenzaldehyde (122 mg, 1 mmol), and glacial acetic acid (2 mL) were sequentially added to a 25 mL round-bottom flask equipped with a stirrer and a condenser under oil bath conditions at 80 °C. Anhydrous ethanol (5 mL) was used as the solvent, and the reaction was stopped after 8 hours. Solid was observed to be drawn out. The reaction mixture was filtered with methanol as a washing agent to give compound 8. The yield of the target product was 57.6% (133.5 mg). The melting range was 277-280 °C.

[0134] Spectral data of synthesized benzo-α-pyranone derivatives

[0135] Using modern spectroscopic techniques, nuclear magnetic resonance hydrogen spectroscopy (NMR) 1 H NMR and carbon nuclear magnetic resonance (NMR) 13 The structure of the synthesized compound was characterized by C NMR.

[0136] 1. Compound 1

[0137] 1 H NMR (600MHz, Chloroform-d) δ8.08(s,1H),7.77(d,J=8.6Hz,1H),7.76-7.68(m,2H),7.34(d,J=8.6Hz,1H),6.47(d,J=9.5Hz,1H),4.00(s,3H).

[0138] 13 C NMR (151MHz, Chloroform-d) δ160.28,154.74,146.69,143.10,130.16,128.86,126.25,119.00,117.45,117.38,62.28.

[0139] 2. Compound 2

[0140] 1 H NMR(500MHz,Chloroform-d)δ8.56(s,1H),7.95(d,J=2.2Hz,1H),7.90(d,J=9.6Hz,1H),7.80(dd,J=8.5,2.3H z, 1H), 7.39 (d, J = 8.4Hz, 1H), 7.11 (d, J = 7.1Hz, 1H), 6.87 (d, J = 7.1Hz, 2H), 6.32 (d, J = 9.7Hz, 1H), 2.2 (s, 6H).

[0141] 13C NMR(151MHz,Methanol-d4)δ161.67,156.3,152.28,144.48,142.06,135.76,1 33.03,135.5,129.00,128.18,128.04,124.22,120.28,115.80,115.55,16.51.

[0142] 3. Compound 3

[0143] 1 H NMR (600MHz, DMSO-d6) δ7.83(d,J=8.7Hz,1H),7.66(dd,J=20.5,8.5Hz,2H),7.43(t,J=7.6Hz,1H),7.38–7.29(m,2H) ,6.91(dd,J=8.7,2.3Hz,1H),6.85(d,J=2.3Hz,1H),6.73(dd,J=8.9,2.4Hz,1H),6.64(d,J=2.4Hz,1H),2.21(s,3H).

[0144] 13 C NMR(151MHz,DMSO-d6)δ180.03,162.85,161.66,161.45,158.62,157.15,154.86,153 .84,136.47,126.01,125.88,124.69,112.76,107.53,103.57,103.30,100.36,56.82.

[0145] 4. Compound 4

[0146] 1 H NMR (600MHz, DMSO-d6) δ10.35(s,1H),7.83(d,J=8.7Hz,1H),7.66(dd,J=20.5,8.5Hz,2H),7.43(t,J= 7.6Hz,1H),7.38–7.29(m,2H),6.85(d,J=2.3Hz,1H),6.64(d,J=2.4Hz,1H),3.85(s,3H),2.27(s,3H).

[0147] 13C NMR(151MHz,DMSO-d6)δ180.13,161.72,158.75,155.19,155.00,151.81,136.60,129.3 2,128.53,122.60,121.09,112.03,110.76,107.54,103.54,100.21,92.39,56.81,8.54.

[0148] 5. Compound 5

[0149] 1 H NMR (600MHz, DMSO-d6) δ10.33(s,1H),8.66(s,1H),7.72(d,J=8.9Hz,1H),7.56–7.53(m,2H),7.43(dd ,J=8.1,1.9Hz,1H),6.83(d,J=8.9Hz,1H),6.66–6.60(m,1H),5.76(s,1H),3.61(s,3H),2.16(s,3H).

[0150] 13 C NMR (151MHz, DMSO) δ159.07,155.10,153.49,152.35,148.62,147.79,144.84,130. 04,129.18,121.40,119.24,115.85,115.49,111.87,110.82,106.99,56.24,8.60.

[0151] 6. Compound 6

[0152] 1 H NMR(600MHz, DMSO-d6)δ9.94(s,1H),8.29(d,J=3.1Hz,1H),8.14–8.08(m,1H),7.52(dt,J=8.1,1.0Hz,1H),7.40(d,J= 8.6Hz,1H),7.24(dt,J=26.2,7.4Hz,2H),6.57(dd,J=8.6,2.2Hz,1H),6.41(d,J=2.2Hz,1H),5.91(s,1H),2.4(s,3H).

[0153] 13C NMR(151MHz,DMSO-d6)δ185.43,161.20,155.93,154.22,153.54,138.92,137.52,126.68 ,124.59,123.93,122.59,121.29,118.63,112.88,111.63,109.31,107.94,98.98,18.47.

[0154] 7. Compound 7

[0155] 1 H NMR (600MHz, DMSO-d6) δ10.90(s,1H),10.64(s,1H),9.93(s,1H),7.53(d,J=8.6Hz,1H),7.40(d,J=8.5Hz,1H),6 .56(dd,J=8.6,2.2Hz,1H),6.39(dd,J=8.1,2.2Hz,2H),6.32(d,J=2.2Hz,1H),5.91(d,J=1.4Hz,1H),2.4(s,3H).

[0156] 13 C NMR(151MHz,Chloroform-d)δ170.35,168.45,165.97,160.66,159.00,158.28,1 37.90,131.45,120.44,116.37,114.04,113.82,112.67,107.37,103.70,23.24.

[0157] 8. Compound 8

[0158] 1 H NMR(600MHz,DMSO-d6)δ11.60(s,1H),10.77(s,1H),9.71(s,1H),7.46–7.40(m,2H),7.40(s, 1H),6.59–6.54(m,2H),6.41(d,J=2.2Hz,1H),5.90(d,J=1.3Hz,1H),2.30(s,3H),2.4(s,3H).

[0159] 13C NMR(151MHz,DMSO-d6)δ195.55,165.42,163.85,161.69,161.20,155.92,153.54,13 3.54,126.67,114.52,111.63,110.64,109.31,108.52,107.93,98.98,18.47,7.79.

[0160] Antifungal activity of benzo-α-pyranone derivatives

[0161] 1. Test bacteria used in the experiment

[0162]

[0163] The four standard bacterial strains mentioned above were used in this part of the experiments. All strains were provided by the Chemical Ecology Laboratory of the Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, and can also be purchased directly from Gary Chemical Network, Shanghai Boco Biotechnology Co., Ltd., etc.

[0164] 2. Preparation of PDA culture medium

[0165] (1) Weighing and cooking: Calculate the total amount of culture medium required based on the requirement of 10 mL of PDA culture medium per petri dish. Weigh a certain amount of peeled potatoes according to the calculation of adding 200 g of potatoes to every 1000 mL of distilled water. Cut the potatoes into small pieces and put them in a pot. Add 1000 mL of water and heat to a boil in the pot. Cook the potatoes until soft but not mushy. Filter the mixture while hot through 6-8 layers of gauze and discard the residue. Add water to the filtrate to bring it up to 1000 mL.

[0166] (2) Heating to dissolve: Put the filtrate into a pot, add glucose (20g / 1000mL distilled water) and agar powder (18g / 1000mL distilled water), heat over low heat and stir constantly with a glass rod to prevent the agar powder from sticking to the bottom or overflowing. After the agar is completely dissolved, add water to the required amount.

[0167] (3) Dispensing and autoclaving: Dispense the prepared culture medium into 500ml Erlenmeyer flasks. It is advisable to dispense into the Erlenmeyer flasks no more than half full of their volume, seal them with sealing film, and autoclave them for later use.

[0168] 3. Preparation of compound solutions of synthesized benzo-α-pyranone derivatives

[0169] The compound solution was prepared to a concentration of 200 μg / mL by accurately weighing 24 mg of the compound into a centrifuge tube, adding 1200 μL of dimethyl sulfoxide (DMSO) using a pipette, and sonicating until completely dissolved. The compound solution was then sterilized under a UV lamp for 30 min.

[0170] 4. Experimental Procedure

[0171] Place 10 mL of PDA medium in a petri dish, add 100 μL of the compound solution, gently shake to mix, label, and cool horizontally. Use 100 μL of dimethyl sulfoxide (DMSO) as a blank control. Perform three parallel experiments. Use commercially available fungicides such as carbendazim and chlorothalonil as positive controls. Use a 0.7 cm diameter punch to collect vigorous mycelial cakes and punch concentric circles. Inoculate the center of fresh medium and invert the dish in a 25°C incubator. Measure the colony diameter after 96 hours using the cross-hatching method, calculate the average diameter, and determine the inhibitory rate of the compound.

[0172] Formula for calculating antibacterial rate: I = [(D0 - D] t [(D0-0.7)]×100%

[0173] (I: Mycelial growth inhibition rate, D0: Diameter of blank colony, D) t (Diameter of colonies after chemical treatment)

[0174] 5. Measurement Results

[0175] The inhibitory activity of the synthesized benzo-α-pyranone derivatives against four common plant pathogens—Botrytis cinerea, Alternaria solanacea, Fusarium oxysporum, and Alternaria alternata—was determined using the mycelial growth rate method described above. The experimental results are shown in Table 1.

[0176] Table 1

[0177]

[0178] Note: Higher values ​​in Table 1 indicate higher antibacterial activity, while negative values ​​indicate that the compound promotes fungal growth.

[0179] In this invention, the antifungal activity study of benzo-α-pyranone derivatives used four common plant pathogenic fungi—Botrytiscinerea, Alternaria solani, Fusarium oxysporum, and Alternaria alternata—as the activity screening targets. The mycelial growth rate method was used to screen for pathogenic fungi, which can lay the foundation for the development of novel plant-derived pesticides.

[0180] As shown in Table 1, at a mass concentration of 200 μg / mL, compounds 1-8, the eight benzo-α-pyranone derivatives synthesized in this invention, all exhibited varying degrees of antifungal activity against the four tested plant pathogenic fungi, demonstrating their potential as novel plant-derived pesticide antifungal agents. It should be noted that carbendazim or chlorothalonil have significant structural differences from the coumarin compounds of this invention and are not used for comparison with the antifungal rates of the compounds synthesized in this patent. Using only carbendazim and chlorothalonil as positive controls sufficiently demonstrates the reliability of this experiment.

[0181] In addition, compounds 6, 7, and 8 of the present invention exhibit higher antibacterial activity against Alternaria alternata than the positive controls chlorothalonil and carbendazim; compounds 2, 6, 7, and 8 exhibit higher antibacterial activity against Alternaria solanaceus than the positive controls chlorothalonil and carbendazim; compound 8 exhibits higher antibacterial activity against Botrytis cinerea than the positive control chlorothalonil; and compound 8 exhibits the same antibacterial activity against Fusarium oxysporum as chlorothalonil. Compounds 6, 7, and 8 show better antibacterial effects and are more likely to be developed into new coumarin antibacterial agents.

[0182] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0183] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0184] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application’s filing, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0185] In the context of this specification, except where expressly stated otherwise, any matters or issues not mentioned shall apply directly to those known in the art without any modification.

Claims

1. A benzo-α-pyranone derivative, characterized in that, The benzo-α-pyranone derivatives are selected from the compounds shown below; 。 2. A method for preparing the benzo-α-pyranone derivative according to claim 1, characterized in that, Selected from method (1): Method (1): The compound shown in formula A and R 4′ -NH2·HCl, a weak base or a weak acid, react in a solvent upon heating to produce a compound of formula (AA); The structure of the compound shown in Formula A is as follows: ； R 4′ -NH2·HCl is methoxyamine hydrochloride.

3. The method for preparing benzo-α-pyranone derivatives according to claim 2, characterized in that, In method (1), the solvent is selected from methanol or ethanol; and / or, The weak base is selected from at least one of pyridine or triethylamine; the weak acid is selected from glacial acetic acid; and / or, The heating temperature is 75-100℃; and / or, The heating time is 3-6 hours; and / or, The compound shown in Formula A and R 4′ The molar ratio of -NH2·HCl is 1:(0.8~1.4); and / or, The molar volume ratio of the compound shown in Formula A to the solvent is 1 mmol: (5~8) mL; and / or, When reacting with a weak base, the molar ratio of the compound shown in Formula A to the weak base is 1:(1~1.35); or, When reacting with a weak acid, the molar volume ratio of the compound shown in Formula A to the weak acid is 1 mmol: (1~3) mL.

4. A method for preparing the benzo-α-pyranone derivative according to claim 1, characterized in that, Selected from method (2): Method (2): The compound shown in formula D, The mixture of p-toluenesulfonic acid or glacial acetic acid, optionally in a solvent, and heated reacts to produce the compound shown in formula (AA); The structure of the compound shown in formula D is as follows: ; It consists of methyl benzoylformate and vanillin.

5. The method for preparing benzo-α-pyranone derivatives according to claim 4, characterized in that, Choose from the following methods: In method (2), when reacting with p-toluenesulfonic acid, the following steps are included: Will Grind and mix with p-toluenesulfonic acid until homogeneous, add the compound shown in formula D and continue grinding. After thorough grinding, heat to react and generate the compound shown in formula (AA). The molar ratio of the compound to that shown in formula D is 1:(0.9-1.2); and / or, The molar ratio of the compound shown in Formula D to p-toluenesulfonic acid is 1:(0.15-0.4); and / or, The temperature of the heating reaction is 60-100℃; and / or, The heating reaction time is 3-6 hours.

6. The method for preparing benzo-α-pyranone derivatives according to claim 4, characterized in that: In method (2), when reacting with glacial acetic acid, the following steps are included: The compound shown in formula D, The solvent and glacial acetic acid were mixed and heated to produce the compound shown in formula (AA); The molar ratio of the compound to that shown in formula D is 1:(0.6-1.2); and / or, The molar volume ratio of acetic acid to glacial acetic acid is 1 mmol: (1~3) mL; and / or, The molar volume ratio of the solvent to the total volume is 1 mmol: (4~8) mL; and / or, The solvent is selected from ethanol; and / or, The temperature for heating the reaction is 60-100℃; and / or, The heating reaction time is 5-10 h.

7. The use of a benzo-α-pyranone derivative in the preparation of an antimicrobial agent for at least one of the pathogens selected from Botrytis cinerea, Alternaria solanacea, Fusarium oxysporum and Alternaria spp.; The benzo-α-pyranone derivative is the benzo-α-pyranone derivative as described in claim 1. 。

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