A class of flavonoid hydrazone-containing compounds, their preparation methods and applications

Abstract

This invention discloses a class of flavonoid hydrazone compounds, their preparation methods, and applications. Based on the flavonoid core structure, a series of hydrazone-containing compounds were synthesized, and it was found that these compounds have good inhibitory effects on pathogenic bacteria. They exhibit good inhibitory effects against plant pathogens such as Fusarium head blight of wheat, Verticillium wilt of eggplant, Staphylococcus aureus, Sclerotinia sclerotiorum of rapeseed, Fusarium wilt of pepper, Rhizoctonia solani of rice, Alternaria alternata of tobacco, Botrytis cinerea, Colletotrichum spp., Anthracnose of tea, Colletotrichum gloeosporioides, Bacteroides oryzae of rice, Citrus canker, and Actinidia kiwifruit canker, showing great development potential.

Description

Technical Field

[0001] This invention relates to the field of medicinal chemistry, and in particular to a class of flavonoid hydrazone compounds, their preparation methods, and applications. Background Technology

[0002] Plant diseases cause immense damage to agricultural production, severely impacting food production and agricultural development. Common plant diseases include fungal diseases, bacterial diseases, and viral diseases. As the largest category of plant diseases, those caused by plant pathogenic fungi significantly reduce crop yields, and the highly toxic secondary metabolites produced after plant infection also seriously threaten food security and human health. Therefore, there is an urgent need to develop novel pesticide molecules with novel structures and unique mechanisms of action.

[0003] Flavonoids are widely found in various plants and have high application value in medicine and pesticides. Representative natural flavonoids include luteolin, flavonoid succinate, puerarin, quercetin, 7,8-dihydroxyflavone, flavonoid succinate, and rutin, which are widely distributed in the plant kingdom, mainly found in medicinal herbs such as honeysuckle, chrysanthemum, catnip, and prunella vulgaris, as well as vegetables such as thyme, Brussels sprouts, cabbage, cauliflower, beet, cabbage, and carrots. The basic core of flavonoids consists of a γ-pyranone and a benzene ring, serving as the basic skeleton and pharmacophore. This skeleton is widely present in natural products. Further research on these flavonoids has revealed their antibacterial, anti-inflammatory, antioxidant, antiviral, and antitumor biological activities, providing important research and development prospects for the discovery of lead compounds.

[0004] In 2021, Chen et al. synthesized a novel class of benzimidazole-containing flavonoid derivatives. Most of the target compounds showed good inhibitory effects against *Rhizopus citrus canker*, *Rhizopus spp.*, and *Rhizopus spp.* bacterial blight of rice. Antiviral bioassays showed that the compounds also exhibited significant therapeutic and protective activity against tobacco mosaic virus (TMV), superior to or approaching that of ningnanmycin. Microthermophoresis (MST) also revealed that the compound's binding to the TMV coat protein (TMV-CP) produced K... d The value was 1.049±0.582 μmol / L, which was better than that of Ningnanmycin. d The value was (1.058±0.286 μmol / L). Studies have shown that benzimidazole-containing flavonoid derivatives are promising agricultural antibacterial and antiviral agents.

[0005] In 2024, Zhao et al. discovered new antitumor drugs based on the structure of natural products, synthesized two series of 2-phenylglycine / leucine hybrid isoflavone derivatives, and evaluated their antiproliferative activity against human cancer cells. Most of the target compounds showed effective antiproliferative activity against HeLa cells, close to the positive control. The compound exhibited significant broad-spectrum inhibitory activity against cancer cells (HeLa, MCF-7, MDA-MB231, and H460 cells), with an IC50 value of [missing information]. 50 The concentrations were 1.94±0.26 μM, 4.75±0.38 μM, 8.56±0.19 μM, and 4.36±0.11 μM, respectively. Furthermore, this class of compounds was found to inhibit HeLa cell proliferation, apoptosis, invasion, and migration. Molecular docking experiments and enzyme activity inhibition assays further investigated the possible mechanism of action. This study discovered a novel flavonoid lead compound, which holds great promise for further anti-tumor research.

[0006] Furthermore, hydrazone structures, due to their -NHN=CH- structure, possess strong coordination ability, diverse coordination modes, and unique biological activities. Many small molecules of antibacterial pesticides contain such structural fragments, such as the fungicides benquiox and ferimzone. To find highly effective fungicidal compounds, this invention uses flavonoid natural product cores as the backbone, introducing hydrazone structures that may enhance the biological activity of target compounds into this system. Flavonoid compounds containing hydrazone structural units are synthesized, and their biological activity is tested. It has been found that these compounds exhibit high biological activity and possess significant development and economic value. Summary of the Invention

[0007] One objective of this invention is to provide a flavonoid hydrazone derivative or its stereoisomer, its salt or its solvate.

[0008] Another object of the present invention is to provide a composition containing the above-mentioned compound or its stereoisomer, its salt or its solvate.

[0009] Another object of the present invention is to provide the use of the above-mentioned compound or its stereoisomer, its salt or its solvate, or the composition thereof.

[0010] Another object of the present invention is to provide a method for controlling agricultural pests and diseases using the above-mentioned compound or its stereoisomer, its salt or its solvate, or the composition thereof.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] A compound containing a flavonoid hydrazone derivative or its stereoisomer, its salt or its solvate, having a structure as shown in general formula (I):

[0013]

[0014] in,

[0015] R1 is a halogen, alkoxy, alkyl, or nitro group; R2 is a halogen, a substituted benzene ring, a heterocyclic ring, or an alkyl group with mono- or more substitutions; R3 is hydrogen, an alkoxy group, or a halogen; R4 is a halogen, a substituted benzene ring, a heterocyclic ring, or an alkyl group with mono- or more substitutions.

[0016] The alkoxy group is a C1-C6 alkoxy group.

[0017] The alkyl group is a C1-C6 alkyl group.

[0018] The present invention also provides a method for preparing the aforementioned flavonoid hydrazone derivatives or their stereoisomers, their salts or their solvates.

[0019]

[0020] Where X is an element of N, n = 1, and X is an element of S, n = 2.

[0021] The specific compounds containing flavonoid hydrazone derivatives or their stereoisomers, salts or solvates are selected from the following compounds: The synthetic methods are as follows:

[0022]

[0023] The present invention also provides a composition comprising the said compound or its stereoisomer, its salt or its solvate, and agriculturally usable adjuvants or fungicides, insecticides or herbicides; preferably, the formulation of the composition is selected from emulsifiable concentrates (EC), powders (DP), wettable powders (WP), granules (GR), aqueous solutions (AS), suspensions (SC), ultra-low volume sprays (ULV), soluble powders (SP), microcapsules (MC), fumigants (FU), emulsions (EW), and water-dispersible granules (WG).

[0024] The compound or its stereoisomer, its salt or its solvate, or the composition thereof can be used to prevent and control agricultural pests and diseases. Preferably, the agricultural pests and diseases are bacterial or fungal plant diseases; more preferably, the agricultural pests and diseases are plant leaf blight and plant canker; most preferably, the agricultural pests and diseases are plant diseases such as Fusarium wilt of wheat, Verticillium wilt of eggplant, Botrytis cinerea, Sclerotinia sclerotiorum, Fusarium wilt of pepper, Rhizoctonia solani of rice, Alternaria alternata of tobacco, Botrytis cinerea, Colletotrichum sorghum, Anthracnose of tea, Colletotrichum gloeosporioides, Bacteroides blight of rice, Citrus canker, Actinidia kiwifruit canker, Tobacco mosaic virus, Cucumber mosaic virus, etc.

[0025] This invention also provides a method for preventing and controlling agricultural pests and diseases. The method involves applying the compound or its stereoisomer, its salt or its solvate, or the composition to a harmful substance or its habitat. Preferably, the agricultural pests and diseases are bacterial or fungal plant diseases. More preferably, the agricultural pests and diseases are plant diseases such as Fusarium head blight of wheat, Verticillium wilt of eggplant, Staphylococcus aureus, Sclerotinia sclerotiorum of rapeseed, Fusarium wilt of pepper, Rhizoctonia solani of rice, Alternaria alternata of tobacco, Botrytis cinerea, Colletotrichum sorghum, Anthracnose of tea, Colletotrichum gloeosporioides, Bacteroides blight of rice, Citrus canker, Actinidia kiwifruit canker, Tobacco mosaic virus, Cucumber mosaic virus, etc.

[0026] The present invention also provides a method for protecting plants from agricultural pests and diseases, comprising the steps of contacting the plant with the compound or its stereoisomer, its salt or its solvate, or the composition thereof.

[0027] The term "alkyl" as used here refers to both branched and straight-chain saturated hydrocarbon groups having a specific number of carbon atoms. For example, "C 1-10 Alkyl (or alkylene) refers to C1, C2, C3, C4, C5, C6, C7, C8, C9, and C10 alkyl groups. Additionally, for example, "C 1-6 "Alkyl" refers to an alkyl group having 1 to 6 carbon atoms. Alkyl groups can be unsubstituted or substituted, whereby one or more of their hydrogen atoms are replaced by other chemical groups. Examples of alkyl groups include, but are not limited to, methyl (Me), ethyl (Et), propyl (such as n-propyl and isopropyl), butyl (such as n-butyl, isobutyl, and tert-butyl), pentyl (such as n-pentyl, isopentyl, and neopentyl), and the like. Furthermore, when hexyl, heptyl, and octyl are mentioned, all their isomers are included in addition to n-hexyl, n-heptyl, and n-octyl.

[0028] "Alkenyl" refers to hydrocarbons that include both straight-chain and branched structures and have one or more carbon-carbon double bonds that appear at any stable point in the chain. For example, "C 2-6 The term "alkenyl" (or "alkenylidene") aims to include C2, C3, C4, C5, and C6 alkenyl groups. Examples of alkenyl groups include, but are not limited to, vinyl, 1-propenyl, 2-propenyl, 2-butenyl, 3-butenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, 5-hexenyl, 2-methyl-2-propenyl, 4-methyl-3-pentenyl, and their analogues.

[0029] "Alkyne" refers to hydrocarbons that can be either straight-chain or branched and have one or more carbon-carbon triple bonds that appear at any stable point in the chain. For example, "C 2-6The purpose of "alkynyl" (or ynylene) is to include C2, C3, C4, C5 and C6 alkynyl groups; such as ethynyl, propynyl, butynyl, pentylyl, hexynyl and their analogues.

[0030] The term "substituted" as used herein refers to the substitution of one or more hydrogen atoms on a specified atom or group by a chosen specified group, provided that the substitution does not exceed the general valence of the specified atom. Unless otherwise specified, substituents are named to the central structure. For example, it can be understood that when (cycloalkyl)alkyl is a possible substituent, the substituent's connection point to the central structure is within the alkyl moiety. Cyclic double bonds as used herein are double bonds formed between two adjacent ring atoms (e.g., C=C, C=N, or N=N). When substitution is mentioned, especially polysubstitution, it refers to the substitution of multiple substituents at various positions on a specified group, such as dichlorophenyl referring to 1,2-dichlorophenyl, 1,3-dichlorophenyl, and 1,4-dichlorophenyl.

[0031] Combinations of substituents and / or variables are permitted only when these combinations yield stable compounds or useful synthetic intermediates. A stable compound or stable structure implies that the compound is sufficiently stable to be isolated from the reaction mixture with useful purity, subsequently formulated to form an effective therapeutic agent. Preferably, the compound currently does not contain N-halogens, S(O)₂H, or S(O)H groups.

[0032] The term "aryl" refers to a monocyclic or bicyclic aromatic hydrocarbon group, such as phenyl and naphthyl, having 6 to 12 carbon atoms in the ring moiety, each of which can be substituted.

[0033] The term "halogen" or "halogen atom" refers to chlorine, bromine, fluorine, and iodine.

[0034] The term "heteroaryl" refers to substituted and unsubstituted aromatic 5- or 6-membered monocyclic groups, 9- or 10-membered bicyclic groups, and 11- to 14-membered tricyclic groups, having at least one heteroatom (O, S, or N) in at least one ring, wherein the heteroatom-containing ring preferably has 1, 2, or 3 heteroatoms selected from O, S, and N. Each ring of a heteroatom-containing heteroaryl may contain one or two oxygen or sulfur atoms and / or 1 to 4 nitrogen atoms, provided that the total number of heteroatoms in each ring is 4 or less, and each ring has at least one carbon atom. The fused rings completing the bicyclic and tricyclic groups may contain only carbon atoms and may be saturated, partially saturated, or unsaturated. Nitrogen and sulfur atoms may optionally be oxidized, and nitrogen atoms may optionally be quaternized. Bicyclic or tricyclic heteroaryl groups must include at least one fully aromatic ring, and the other fused rings may be aromatic or non-aromatic. Heteroaryl groups may be attached to any available nitrogen or carbon atom in any ring. Where valence permits, if the other ring is a cycloalkyl or heterocyclic ring, it may optionally be substituted with =O (oxygen).

[0035] Exemplary monocyclic heteroaryl groups include pyrrole, pyrazolyl, pyrazolinyl, imidazolyl, oxazolyl, isoxazolyl, thiazolyl, thiadiazolyl, furanyl, thiophenyl, oxadiazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, triazinyl, and their analogues.

[0036] Exemplary bicyclic heteroaryl groups include indolyl, benzothiazolyl, benzodioxazolyl, benzoxazolyl, benzothiophenyl, quinolinyl, tetrahydroisoquinolinyl, isoquinolinyl, benzoimidazolyl, benzofuranyl, indoleazinyl, benzofuranyl, crononeyl, coumarinyl, benzofuranyl, cenolinyl, quinoxalinyl, indazoleyl, pyrrolopyridyl, fluoropyridyl, dihydroisoindolyl, tetrahydroquinolinyl, and their analogues.

[0037] Unless otherwise specified, the compounds of this invention are understood to include both their free state and their salts. The term "salt" means an acidic and / or basic salt formed from an inorganic and / or organic acid and base. Additionally, the term "salt" may include zwitterions (internal salts), such as when a compound of formula I contains a basic segment such as an amine or pyridine or imidazole ring, and an acidic segment such as a carboxylic acid. Pharmaceutically acceptable (i.e., non-toxic, physiologically acceptable) salts are preferred, such as acceptable metal and amine salts, wherein the cation does not significantly contribute to toxicity or the biological activity of the salt. However, other salts may be useful, such as those prepared using separation or purification steps, and are therefore also included within the scope of this invention.

[0038] Preferably, C1-C 10 Alkyl groups refer to methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, and their isomers; C1-C 10 Alkoxy refers to methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy, heptoxy, octoxy, nonoxy, decoxy, and their isomers; C2-C5 alkenyl refers to vinyl, propenyl, allyl, butenyl, pentenyl, and their isomers. Similarly, C1-C5 alkyl refers to methyl, ethyl, propyl, butyl, pentyl, and their isomers; C1-C5 alkoxy refers to methoxy, ethoxy, propoxy, butoxy, pentoxy, and their isomers.

[0039] When referring to substituents, such as alkenyl, alkynyl, alkyl, halogen, aryl, heteroaryl, alkoxy, cycloalkyl, hydroxyl, amino, mercapto, or phosphinyl, or when these substituents specifically refer to a particular alkenyl, alkynyl, alkyl, halogen, aryl, heteroaryl, alkoxy, cycloalkyl, hydroxyl, amino, mercapto, or phosphinyl group, it refers to one to three of the aforementioned substituents. For example, methylphenyl refers to a phenyl group with one to three methyl-substituted groups.

[0040] By adopting the above technical solutions, this invention synthesizes a series of acylhydrazone-containing compounds based on the flavonoid core structure. It has been found that these compounds have good inhibitory effects on pathogenic bacteria, exhibiting excellent inhibitory effects against plant pathogens such as Fusarium head blight of wheat, Verticillium wilt of eggplant, Staphylococcus aureus, Sclerotinia sclerotiorum of rapeseed, Fusarium wilt of pepper, Rhizoctonia solani of rice, Alternaria alternata of tobacco, Botrytis cinerea, Colletotrichum spp., Anthracnose of tea, Colletotrichum gloeosporioides, Bacteroides oryzae of rice, Citrus canker, and Actinidia kiwifruit canker. This provides an important scientific basis for the research and development of new pesticides. Attached Figure Description

[0041] Figure 1 This diagram illustrates the in vitro inhibition effect of compound H9.

[0042] Figure 2 A diagram illustrating the in vitro activity of compound G24 against Sclerotinia sclerotiorum, rapeseed. Detailed Implementation

[0043] Example 1

[0044] The present invention will be further illustrated below through examples. It should be understood that the methods described in the examples are merely illustrative and not intended to limit the invention. Simple modifications to the preparation methods of the present invention within the framework of the present invention's concept are all within the scope of the invention. All raw materials and solvents used in the examples are commercially available products.

[0045] Substituted 4-oxo-4H-1-benzopyran-3-carboxaldehyde (0.01m) and benzoylhydrazine (0.01m) were added to anhydrous ethanol solution, and 8 drops of glacial acetic acid were added dropwise as a catalyst. The mixture was stirred at room temperature for 4 hours. The solvent was evaporated under reduced pressure, and the product H was obtained by recrystallization from ethanol.

[0046] For example, the synthesis method of compound H1: 6-isopropyl-4-oxo-4H-1-benzopyran-3-carboxaldehyde (0.01m) and 4-fluorobenzoylhydrazine (0.01m) were added to 10 mL of anhydrous ethanol, and 8 drops of acetic acid were slowly added dropwise as a catalyst. The reaction was stirred at room temperature for 4 hours, and the reaction was monitored by TLC (ethyl acetate: petroleum ether = 1:3). After the reaction was completed, the solvent was evaporated and recrystallized with ethanol to obtain the target compound H1.

[0047] Other target compounds and G were synthesized using the corresponding starting materials or substituents, following the steps outlined in the examples.

[0048] For example, the synthesis method of compound G1 is as follows: 6-isopropyl-4-oxo-4H-1-benzopyran-3-carboxaldehyde (0.01m) and 2-fluorobenzenesulfonyl hydrazine (0.01m) are added to 10 mL of anhydrous ethanol, and 8 drops of acetic acid are slowly added dropwise as a catalyst. The reaction is stirred at room temperature for 4 hours, and the reaction is monitored by TLC (ethyl acetate: petroleum ether = 1:3). After the reaction is completed, the solvent is evaporated and recrystallized with ethanol to obtain the target compound G1.

[0049] Table 1. Summary of the structures of target compounds H and G

[0050]

[0051]

[0052]

[0053]

[0054]

[0055] The structures, physicochemical properties, nuclear magnetic resonance and high-resolution mass spectra of the synthesized flavonoid acylhydrazones are shown in Tables 1, 2 and 3.

[0056] Table 2. Physicochemical properties, nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HMR) data of target compound H

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064] Table 3. 1H and 1C NMR spectra of target compound G

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073] Example 2:

[0074] The compounds exhibited good antifungal activity against some fungi. The following examples illustrate their activity against Fusarium graminearum, Sclerotinia sclerotiorum, Fusarium wilt of pepper, Rhizoctonia solani, Verticillium wilt of eggplant, and Cercospora variegata.

[0075] The mycelial growth rate method, also known as the toxic medium method, is one of the routine methods for determining the toxicity of fungicides. The main principle is to mix the test agent with a culture medium and measure the toxicity of the agent by the rate at which colonies grow on the toxic medium. This example uses *Rhizoctonia solani*, *Botrytis cinerea*, *Fusarium graminearum*, *Fusarium wilt* of pepper, and *Verticillium wilt* of eggplant as test subjects, and DMSO (dimethyl sulfoxide) as a blank control.

[0076] The specific procedures are as follows: 1) Weigh an appropriate amount of drug according to the test concentration, dissolve it in DMSO (the amount should not exceed 1% of the final toxic medium), then add 0.1% Tween 20 aqueous solution to make up to 10 mL, pour it into 90 mL of melted PDA medium, mix well, and then pour it into 9 petri dishes for later use; 2) Sterilize the punch (with an inner diameter of 5 mm) by flame, and after it cools, punch holes in the hyphae near the edge of the pre-activated strain, and use an inoculation needle to place the hyphae facet to the center of the toxic medium. After treatment, incubate them all at 25℃; 3) After the colony diameter of the control group grows to 5.5-6.0 cm, use the cross-cross method to determine the colony diameter of the control group and each drug treatment group; 4) Calculate the inhibition rate (%) using the following formula:

[0077] Inhibition rate % = (CT) / (C-0.5)×100%;

[0078] Where C is the colony diameter of the control group, T is the colony diameter of the drug-treated group, and 0.5 is the diameter of the inoculated mycelium.

[0079] EC 50Median effective concentration (MEC) is an important indicator for evaluating the sensitivity of plant pathogens to compounds, and it is also a crucial parameter for setting compound concentrations when studying the mechanism of action of compounds. In concentration gradient experiments, five appropriate concentrations were set using the two-fold dilution method. Finally, the inhibition rate of the agent against the plant pathogen and the agent concentration were converted into logarithmic values, and the toxicity curve was obtained through regression analysis using SPSS software to calculate the EC50. 50 .

[0080] The embodiments of this invention are provided to illustrate the technical solutions of this invention, but the content of the embodiments is not limited thereto. The experimental results of the target compound are shown in Tables 4 and 5.

[0081] Table 4. Antifungal inhibition rate (%) of flavonoid hydrazone compound H at a concentration of 25 μg / mL.

[0082]

[0083]

[0084]

[0085] In the in vitro experiments, using marketed drugs azoxystrobin, carbendazim, and thiabendazole as positive controls, the H-series compounds were tested for their activity against Fusarium wilt of wheat, Sclerotinia sclerotinia of rapeseed, Fusarium wilt of pepper, Rhizoctonia solani of rice, Verticillium wilt of eggplant, and Botrytis cinerea. Table 4 shows that the tested target compounds H5, H7, H13, H16, H18, H22, and H28 were superior to or close to the control drugs azoxystrobin (49.4%) and thiabendazole (64.2%) against Fusarium wilt of wheat at a concentration of 25 μg / mL. Table 2 shows that most of the tested target compounds had some inhibitory activity against Sclerotinia sclerotinia of rapeseed, with compound H9 showing inhibition rates close to those of the control drugs azoxystrobin, carbendazim, and thiabendazole at a concentration of 25 μg / mL. Table 2 shows that most of the tested target compounds exhibited better inhibition rates against *Fusarium wilt* causal agent of pepper disease than the control drug thiabendazole (15.6%), but lower than azoxystrobin (68.6%) and carbendazim (92.0%). Compound H16 showed the highest inhibition rate at 25 μg / mL, at 55.9%. Table 2 also shows that most of the tested target compounds exhibited some inhibitory activity against *Sheath blight* causal agent of rice disease, showing activity superior to or close to that of the control drug thiabendazole. Furthermore, Table 2 shows that most of the tested target compounds showed better inhibition rates against *Verticillium wilt* causal agent of eggplant disease than the control drug thiabendazole (31.6%), with compound H22 showing inhibition rates close to that of the control drug azoxystrobin (72.4%) at 25 μg / mL. As shown in Table 2, most of the target compounds showed better inhibition rates against the grape causal agent sclerotinia than the control drugs thiabendazole (29.4%) and azoxystrobin (52.1%). Among them, compound H19 showed the highest inhibition rate of 61.6% at a concentration of 25 μg / mL.

[0086] Table 5. The effects of flavonoid hydrazone H on EC50 of *Sclerotinia sclerotiorum*. 50 value

[0087]

[0088]

[0089] Based on the good bioactivity of most compounds against *Sclerotinia sclerotiorum*, we further screened the H-series compounds against *Sclerotinia sclerotiorum*, as shown in Table 5. Most compounds exhibited good EC50 activity. 50 Values, of which compounds H9, H22 and H23 have EC values 50 The value is better than or close to that of commercial drugs carbendazim (0.37 μg / mL) and azoxystrobin (0.71 μg / mL).

[0090] We first performed a complete EC50 analysis on the G-series compounds from *Sclerotinia sclerotiorum*. 50 The tests revealed that most compounds exhibited good inhibitory activity, as shown in Table 6. Most compounds also showed good EC50 values. 50The values ​​of EC5 for compounds G1, G2, G7, G12, G18, G19, G21, G22, G23, G24 and G26. 50 The value is better than or close to that of commercial drugs carbendazim (0.37 μg / mL) and azoxystrobin (0.71 μg / mL).

[0091] Table 6. EC50 of flavonoid sulfonylhydrazone compound G against Sclerotinia brassicae. 50 value

[0092]

[0093]

[0094] We further tested the bioactivity of compounds G2, G24, and G26 against five other fungal species, as shown in Table 7. The inhibitory activity of compounds G2, G24, and G26 against *Fusarium graminearum* was close to that of azoxystrobin (41.2%); their inhibitory activity against *Fusarium wilt* of pepper was superior to thiabendazole (15.6%); their inhibitory activity against *Sheath blight* of rice was superior to thiabendazole (31.2%); and their inhibitory activity against *Botrytis cinerea* was superior to thiabendazole (29.4%). These results indicate that the synthesized compounds possess broad-spectrum fungicidal activity and can control a variety of fungal diseases.

[0095] Table 7. Inhibition rate of flavonoid sulfonylhydrazone compound G at 25 μg / mL against five other fungi.

[0096]

[0097] Example 3:

[0098] The inhibition rate of the target compounds against plant pathogenic bacteria was tested using the turbidimetric method. The test subjects were *Xoo* (bacterium oryzae of rice), *Xac* (bacterium citrus canker), and *PSA* (bacterial canker of kiwifruit). DMSO was dissolved in the culture medium as a blank control. *Xoo* (bacterium oryzae of rice) was placed in NB medium and cultured in a constant temperature shaker at 28℃ and 180 rpm until the logarithmic growth phase. *Xac* (bacterium citrus canker) was placed in NB medium and cultured in a constant temperature shaker at 28℃ and 180 rpm until the logarithmic growth phase. *Xac* (bacterial canker of kiwifruit) was placed in NB medium and cultured in a constant temperature shaker at 28℃ and 180 rpm until the logarithmic growth phase. Prepare different concentrations (e.g., 100, 50 μg / mL) of NB liquid culture medium containing the pathogen and add 5 mL to each test tube. Add 40 μL of NB liquid culture medium containing plant pathogen bacteria to each test tube. Incubate the tubes at 28-30℃ and 180 rpm in a constant temperature shaker for 36 h for rice bacterial blight pathogens, 48 ​​h for citrus canker pathogens, and 36 h for kiwifruit bacterial canker pathogens. Measure the OD of each concentration of bacterial suspension using a spectrophotometer. 595 The value was also measured, and the OD of the corresponding concentration of sterile NB liquid culture medium containing the toxin was also determined. 595 value.

[0099] The effective median concentration of the target compound against plant pathogens was determined using the turbidimetric method. The test subjects were *X. oolong* (bacterial blight of rice), *X. ac* (citrus canker), and *PSA* (bacterial canker of kiwifruit). DMSO was dissolved in the culture medium as a blank control. *X. oolong* (bacterial blight of rice) was placed in NB medium and cultured in a shaker at 28°C and 180 rpm until the logarithmic growth phase. *X. ac* (citrus canker) was placed in NB medium and cultured in a shaker at 28°C and 180 rpm until the logarithmic growth phase. *PSA* (bacterial canker of kiwifruit) was placed in NB medium and cultured in a shaker at 28°C and 180 rpm until the logarithmic growth phase. Different concentrations (e.g., 80, 40, 20, 10, 5 μg / mL) of the agent (compound) containing NB liquid culture medium containing the pathogen were prepared and added to test tubes. 40 μL of NB liquid culture medium containing plant pathogen bacteria was added to each tube. The tubes were then shaken in a constant temperature shaker at 28-30℃ and 180 rpm for 48 h in rice bacterial blight pathogens, 36 h in citrus canker pathogens, and 36 h in kiwifruit bacterial canker pathogens. The OD values ​​of the bacterial solutions at each concentration were measured using a spectrophotometer. 595 The value was also measured, and the OD of the corresponding concentration of sterile NB liquid culture medium containing the toxin was also determined.595 value.

[0100] Corrected OD value = OD value of sterile culture medium - OD value of sterile culture medium

[0101] Inhibition rate % = [(OD value of bacterial suspension in the corrected control medium - OD value of the corrected virus-containing medium) / OD value of bacterial suspension in the corrected control medium] × 100

[0102] The embodiments of this invention are provided to illustrate the technical solutions of this invention, but the content of the embodiments is not limited thereto. The experimental results of some target compounds are shown in Table 8.

[0103] Table 8. Inhibitory activities of compounds H9, H22, G2, G24, and G26 against three plant pathogenic bacteria.

[0104]

[0105]

[0106] In in vitro experiments, using marketed drugs tebuconazole and thiabendazole copper as positive controls, the activities of some compounds H9, H22, G2, G24, and G26 against *Bacillus thuringiensis*, *Actinidia chinensis*, and *Citrus canker* were tested. Table 8 shows the activity of the tested target compounds H9, H22, G2, G24, and G26 against *Bacillus thuringiensis*, *Actinidia chinensis*, and *Citrus canker*.

[0107] Compounds H22, G2, G24, and G26 showed similar inhibition rates against *Actinidia kiwifruit* causal agent at concentrations of 100 μg / mL and 50 μg / mL to the control agents, tebuconazole and thiamethoxam. Table 7 shows that the target compounds H9, H22, G2, G24, and G26 exhibited inhibition rates comparable to thiamethoxam at 100 μg / mL against *Actinidia citrus* causal agent. These results indicate that the synthesized compounds possess potential for controlling bacterial plant diseases.

[0108] Example 4:

[0109] The therapeutic activity of some target molecules against TMV was investigated. For example, selecting 5-7 leaves of the heart-leaf tobacco plant, applying carborundum (emery) to the surface of the leaves, and then inoculating the entire leaf with a brush. After half an hour, the carborundum was rinsed off with clean water, and the leaves were allowed to air dry. The infected left half of the tobacco leaf was then treated with the agent, while the right half was treated with sterile water containing DMSO as a control. Three tobacco plants were treated with each agent, and 3-4 leaves were treated per plant. The plants were then incubated in a greenhouse. After 2-4 days, the number of necrotic spots was observed and recorded, and the inhibition rate was calculated. The protective activity of the target molecules against TMV was also investigated. For example, selecting 5-7 leaves of the heart-leaf tobacco plant, applying the agent to the left half of the leaf, and using sterile water containing DMSO as a control on the right half, and inoculating the entire leaf with the virus 24 hours later. Carborundum was then applied, and the virus was inoculated onto the entire leaf with a brush. After half an hour, the carborundum was rinsed off with clean water, and the leaves were placed in a greenhouse for incubation after drying. Three tobacco plants were treated with each agent, and three to four leaves were selected from each plant. After two to four days, the number of necrotic spots was observed and recorded, and the inhibition rate was calculated.

[0110] Y(%)=(RL) / R×100%

[0111] Where: Y is the inhibition rate of the compound against tobacco mosaic virus; R is the number of necrotic spots in the control group (right half of the leaf); and L is the number of necrotic spots in the treatment group (left half of the leaf).

[0112] Table 9. Inhibitory activities of compounds H9, H22, G2, G24, and G26 against tobacco mosaic virus.

[0113]

[0114] a RBV = Ribavirin b Ningnanmycin

[0115] Table 9 shows that some target molecules exhibited inhibitory activity against TMV at concentrations of 500 and 100 μg / mL. The tested target compounds H9 and H22 showed therapeutic activity against TMV at a concentration of 500 μg / mL similar to that of the control drug ribavirin; H9 and G26 showed protective activity against TMV at a concentration of 500 μg / mL similar to that of ribavirin. These results indicate that the synthesized compounds have potential applications in the prevention and control of plant viral diseases.

Claims

1. A compound containing flavonoid hydrazones, characterized in that: The structural formula is as follows:

2. A composition, characterized in that: It contains the compound of claim 1 and agriculturally usable adjuvants or fungicides, insecticides or herbicides.

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