Formononetin derivative containing piperidine skeleton as well as preparation method and application of formononetin derivative

Abstract

The invention discloses a formononetin derivative containing a piperidine skeleton as well as a preparation method and application of the formononetin derivative, and belongs to the technical field of pesticide synthesis. According to the invention, formononetin is taken as a leading structure, a piperidine skeleton with excellent agricultural activity is introduced into the structure of formononetin, a series of formononetin derivatives containing the piperidine skeleton are synthesized, and the activity of the synthesized formononetin derivatives containing the piperidine skeleton in inhibiting plant pathogenic bacteria is tested, so that the activity of the formononetin derivatives containing the piperidine skeleton in inhibiting plant pathogenic bacteria is obviously improved. It is found that the formononetin derivative containing the piperidine skeleton synthesized by the invention can effectively inhibit plant pathogenic bacteria.

Description

Technical Field

[0001] The present invention relates to the technical field of pesticide synthesis, and in particular to a formononetin derivative containing a piperidine skeleton, and a preparation method and application thereof. Background Art

[0002] Plant diseases pose a serious threat to the growth and development of crops and the quality and safety of agricultural products. Pesticides are crucial for their prevention and control. Common bacterial crop diseases include rice bacterial blight, rice bacterial streak, canker, black spot, and bacterial wilt. Currently, the pesticides used to prevent and control bacterial diseases in my country are mostly copper-based and antibiotic-based, with relatively few new varieties. Currently, the global trend is to vigorously develop "green pesticides" that are environmentally compatible, pollution-free, have unique mechanisms of action, are highly active, easy to use, and affordable. Among the many new pesticides, botanical pesticides have become one of the preferred green pesticides due to their advantages such as easy degradation and pollution-free properties. Consequently, in recent years, many botanical green pesticides with antimicrobial potential have been developed to overcome resistance and pollution issues, while also increasing crop yields and enhancing plant immunity. Natural product-derived green pesticides have proven to be more effective and environmentally friendly than traditional pesticides.

[0003] Formononetin, also known as 7-hydroxy-4-methoxyisoflavone, is an extract from the inflorescence, flowering branches and leaves, and entire herb of the legume plant Formononetin. Studies have shown that formononetin exhibits multiple biological activities in medicine, including antibacterial, antiviral, anticancer, and anti-inflammatory properties. In 2016, Zhang et al. reported a formononetin derivative with potent inhibitory effects against Helicobacter pylori, demonstrating high clinical value and providing a new therapeutic option for H. pylori. In 2021, Zhao et al. discovered that formononetin-7-o-β-(6-acylurea-o-succinyl)-d-glucose significantly improved myocardial damage, reducing lactate dehydrogenase levels and increasing catalase and superoxide dismutase levels. It exhibits high water solubility, low toxicity, and significant anti-myocardial ischemic effects. In 2022, a formononetin derivative synthesized by Fu et al. demonstrated inhibitory effects on prostate cancer cell growth and could serve as a candidate or lead compound for the development of anti-prostate cancer drugs. In 2024, Luo et al. synthesized a derivative of formononetin that can slow down the rate of cell apoptosis, reduce the activity of myocardial enzymes, and reduce the number of autophagic vesicles. It exerts a protective effect by downregulating the expression of autophagic proteins PI3K, Akt, Beclin-1, P62, LC3, and ATG12, and can be used as a potential myocardial protective drug. It can be seen that formononetin and its derivatives have multiple biological activities and are significantly effective in clinical application. However, we also noticed that research on formononetin and its derivatives is mainly concentrated in the pharmaceutical field, while research in the pesticide field is almost blank. Therefore, modification and transformation of potential sites of formononetin is expected to obtain compounds with more diverse product types, richer functional groups, and better biological activity, thereby realizing the leap of its application value from the pharmaceutical field to the pesticide field.

[0004] The piperidine ring, a unique backbone and excellent heterocyclic ring system in drug discovery, plays a vital role in the pharmaceutical industry and serves as a key building block for the construction of active pharmaceutical ingredients. Its derivatives are found in over twenty drugs and alkaloids, including antibacterials, anticancer drugs, antioxidants, antivirals, insecticides, and herbicides. For example, alopiradin and matrine, alkaloids found in Sophora flavescens, contain two fused piperidine rings. Their derivatives possess antiviral, anti-inflammatory, and anti-tumor properties. Piperidin, containing a piperidine ring, is widely used to control barnyard grass and oxtail grass in rice fields. Piperidin is a nicotinoid insecticide developed in my country for controlling homopteran pests such as rice planthoppers and wheat aphids. In addition to these known drugs, researchers are continuously exploring novel bioactive molecules containing piperidine backbones, offering promising prospects for their further application in medicine and agriculture.

[0005] Based on this, introducing the small molecule group piperidine with agricultural activity into the structure of formononetin is expected to give it the ability to target specific cells and tissues while retaining its biological activity, thereby developing antibacterial molecules with excellent agricultural activity. Summary of the Invention

[0006] In view of this, the object of the present invention is to provide a formononetin derivative containing a piperidine skeleton, and a preparation method and application thereof. The formononetin derivative containing a piperidine skeleton provided by the present invention can effectively inhibit plant pathogenic bacteria.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] One of the technical solutions of the present invention is a formononetin derivative containing a piperidine skeleton, the structural formula of which is shown below:

[0009]

[0010] In the formula, n is an integer of 2 to 6; R is independently selected from unsubstituted or optionally substituted phenyl, pyridyl, and thienyl.

[0011] Preferably, the optionally substituted phenyl group contains one or more halogens, one or more C1-C6 alkyl groups, one or more C1-C6 substituted alkyl groups, one or more C1-C6 alkoxy groups, one or more nitro groups, one or more trifluoromethyl groups, one or more tert-butyl groups at the ortho, meta and para positions on the benzene ring; and the pyridine and thienyl groups are unsubstituted pyridine and thienyl groups.

[0012] Preferably, the halogen is F, Cl or Br.

[0013] The second technical solution of the invention is to provide a method for preparing the formononetin derivative containing a piperidine skeleton, comprising the following steps:

[0014] (1) Using formononetin and dibromoalkane as raw materials, heating the reaction in a solvent containing an alkaline catalyst, adding ice water after the reaction to precipitate the product, filtering, and removing impurities from the filter residue to obtain intermediate 1;

[0015] The structural formula of the dibromoalkane is: Wherein, n is an integer from 2 to 6;

[0016] The structural formula of the intermediate 1 is: Wherein, n is an integer from 2 to 6;

[0017] (2) Using intermediate 1 and 4-boc-aminopiperidine as raw materials, heating the reaction in a solvent under alkaline conditions, adding ice water after the reaction is completed to precipitate the product, filtering, drying, and column chromatography to obtain intermediate 2;

[0018] The structural formula of the intermediate 2 is: Wherein, n is an integer from 2 to 6;

[0019] (3) Using intermediate 2 as raw material, the BOC protection was removed under heating conditions to obtain intermediate 3;

[0020] The structural formula of the intermediate 3 is: Wherein, n is an integer from 2 to 6;

[0021] (4) using intermediate 3 and substituted sulfonyl chloride as raw materials, reacting in an ice bath, and after the reaction, purifying the crude product to obtain the formononetin derivative containing piperidine sulfonamide;

[0022] The structural formula of the substituted sulfonyl chloride is: wherein R is independently selected from unsubstituted or optionally substituted phenyl, pyridyl and thienyl;

[0023] (5) Using intermediate 3 and 37% HCl solution as raw materials, an amine salt reaction was carried out under heating conditions to prepare the above-mentioned formononetin derivative containing piperidine hydrochloride.

[0024] Preferably, the molar ratio of formononetin to dibromoalkane in step (1) is 10.0:(50.0-100.0); the temperature of the heating reaction is 60-90°C and the time is 6-10 hours; the alkaline condition is provided by anhydrous potassium carbonate; and the impurity removal step comprises: washing the filter residue with water and petroleum ether in sequence, then beating, standing, filtering, and completing the washing.

[0025] More preferably, the molar ratio of formononetin to anhydrous potassium carbonate in step (1) is 10.0:(20.0-50.0); and the solution used for pulping is a mixture of petroleum ether and ethyl acetate in a volume ratio of 3:1.

[0026] Preferably, in step (2), the molar ratio of the intermediate 1, 4-boc-aminopiperidine, and potassium carbonate is 3.85:(3.85-19.25):(19.25-77.0); the temperature of the heating reaction is 50-90°C, and the time is 8-24 hours; and the solvent used for the column chromatography is a mixture of dichloromethane and methanol in a volume ratio of 25:1.

[0027] Preferably, the step of removing the boc protection in step (3) comprises: dissolving the intermediate 2 in methanol, heating to 40-80° C., adding dropwise a 10-37% HCl solution by mass, reacting for 1-4 hours, and removing the boc protection.

[0028] Preferably, the step (3) further includes a separation step after the removal of the BOC protection. The separation step is specifically as follows: after the removal of the BOC protection, the reaction system is dispersed in ice water, extracted with a small amount of ethyl acetate to remove organic impurities, and then the system is adjusted to 9-10 using a 5wt% NaHCO3 solution, and then extracted with dichloromethane. The extract is evaporated to dryness to obtain intermediate 3.

[0029] Preferably, in step (4), the molar ratio of the intermediate 3, the substituted sulfonyl chloride and potassium carbonate is 1.0:(0.5-1.5):(1.0-3.0); and the reaction time is 0.5-1 h.

[0030] Preferably, the purification step after the reaction in step (4) specifically includes: dispersing the reaction system into water, extracting with dichloromethane, evaporating the extract to dryness, and recrystallizing to complete purification; wherein the solvent used for recrystallization is methanol.

[0031] Preferably, the molar ratio of the intermediate 3 and the 37% HCl solution in step (5) is 1.0:(10.0-30.0).

[0032] The third technical solution of the present invention is to provide an application of the above-mentioned formononetin derivative containing a piperidine skeleton in the preparation of drugs for inhibiting plant pathogenic bacteria.

[0033] Preferably, the plant pathogenic bacteria include one or more of Xoo, Xac, Xcm, Psa, Psoralea corylifolia (Pcb), Ac, and Rs, especially Xoo, Xac, Xcm, and Psa.

[0034] The beneficial technical effects of the present invention are as follows:

[0035] The present invention provides a formononetin derivative containing a piperidine skeleton, a preparation method and an application thereof. The present invention introduces a piperidine skeleton with excellent biological activity into the structure of formononetin, and synthesizes a series of formononetin derivatives containing a piperidine skeleton. By testing the inhibitory activity of the synthesized formononetin derivatives containing a piperidine skeleton on plant pathogenic bacteria, it is found that the synthesized formononetin derivatives containing a piperidine skeleton can effectively inhibit plant pathogenic bacteria, especially Xoo, Xac, Xcm and Psa. DETAILED DESCRIPTION

[0036] Various exemplary embodiments of the present invention are now described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention.

[0037] In addition, for numerical ranges in the present invention, it is understood that each intervening value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any stated value or stated range, and any other stated value or intervening value in the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention.

[0039] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0040] One of the technical objectives of the present invention is to provide a formononetin derivative containing a piperidine skeleton, the structure of which is shown in the following formula:

[0041]

[0042] In the formula, n is an integer of 2 to 6; R is independently selected from any substituted or unsubstituted phenyl, pyridyl, or thienyl.

[0043] In some embodiments, the unsubstituted or optionally substituted phenyl group is one or more halogens containing F, Cl, or Br at the ortho, meta, or para positions on the benzene ring; the methyl, methoxy, nitro, trifluoromethyl, or tert-butyl group is one or more methyl, methoxy, nitro, trifluoromethyl, or tert-butyl group at any position on the benzene ring; the pyridine or thienyl group is an unsubstituted 3-pyridyl or 2-thienyl group;

[0044] The second technical purpose of the present invention is to provide a method for preparing the above-mentioned formononetin derivative containing benzylpiperidine, the steps comprising:

[0045] (1) Using formononetin and dibromoalkane as raw materials, the reaction was heated at 60-90°C in a solvent containing an alkaline catalyst for 6-10 hours. After the reaction was completed, the reaction system was dispersed with ice water, and then filtered, washed, and slurried to obtain intermediate 1.

[0046] The reaction equation is as follows:

[0047]

[0048] In some embodiments, the solvent is ethanol; after the reaction is completed, the reaction solution is dispersed with ice water to precipitate solids; after the precipitated solids, filtration and washing steps are further included; the washing is performed with water and petroleum ether respectively; the slurrying is performed with petroleum ether / ethyl acetate = 3:1 (V / V);

[0049] Wherein, the molar ratio of the formononetin to dibromoalkane is 10.0:(50.0-100.0); the molar ratio of the formononetin to anhydrous potassium carbonate is 10.0:(20.0-50.0);

[0050] (2) Intermediate 1 and 4-boc-aminopiperidine are used as raw materials, and the reaction is heated at 50-90°C in a solvent under alkaline conditions. After the reaction is completed, the reaction system is dispersed with ice water, and then filtered, dried, and column chromatography are performed to obtain intermediate 2.

[0051] The reaction equation is as follows:

[0052]

[0053] In some embodiments, the column chromatography uses an eluent that is a mixture of dichloromethane and methanol in a volume ratio of 25:1;

[0054] Wherein, the molar ratio of the intermediate 1, 4-boc-aminopiperidine and potassium carbonate is 3.85: (3.85-19.25): (19.25-77.0);

[0055] (3) Using intermediate 2 as raw material and methanol as solvent, 10% to 37 wt% HCl solution was added dropwise under the condition of slow heating to 40-80°C and reacted for 1-4 hours to remove the boc protection; after the reaction was completed, the reaction system was dispersed into ice water to remove impurities, and the alkalinity was adjusted with NaHCO3 solution. After extraction, rotary evaporation, and drying, intermediate 3 was obtained.

[0056] The reaction equation is as follows:

[0057]

[0058] In some embodiments, the concentration of the NaHCO3 aqueous solution is 5 wt%; the alkaline pH value is 9 to 10; after adjusting to alkalinity, extraction and reduced pressure rotary evaporation are further included; the extraction is performed using dichloromethane.

[0059] (4) intermediate 3 and substituted sulfonyl chloride are used as raw materials, anhydrous potassium carbonate is used as a catalyst, and the reaction is carried out in a solvent under ice bath conditions for 0.5 to 1 hour. After the reaction, the crude product is purified to obtain the formononetin derivative containing piperidine sulfonamide;

[0060] The reaction equation is as follows:

[0061]

[0062] In some embodiments, the solvent is dichloromethane; the reflux reaction time is 0.5 to 1 hour; after the reaction is completed, the reaction system is dispersed in water, followed by extraction, drying, vacuum rotary evaporation, and recrystallization, and the recrystallization solvent is methanol.

[0063] The molar ratio of the intermediate 3, the substituted sulfonyl chloride and potassium carbonate is 1.0:(0.5-1.5):(1.0-3.0).

[0064] (5) Using intermediate 3 and 37 wt% HCl solution as raw materials and methanol as solvent, an amine salt reaction was carried out under the condition of heating to 60°C for 1 to 2 hours, and then the above-mentioned formononetin derivative containing piperidine hydrochloride was prepared by salt precipitation, filtration and drying.

[0065] The reaction equation is as follows:

[0066]

[0067] The molar ratio of the intermediate 3 to the 37% HCl solution is 1.0:(10.0-30.0). The solvent used in the salt precipitation process is pure ethyl acetate.

[0068] The third technical purpose of the present invention is to provide an application of the above-mentioned formononetin derivative containing a piperidine skeleton in the preparation of drugs for inhibiting plant pathogenic bacteria.

[0069] To achieve the above technical objectives, the present invention provides the following embodiments.

[0070] Example 1

[0071] N-(1-(3-((3-(4-methoxyphenyl)-4-oxyl-4H-chromen-7-yl)oxy)propyl)piperidin-4-yl)-4-methylbenzenesulfonamide (compound number M1) comprises the following steps:

[0072] (1) Synthesis of 7-(3-bromopropoxy)-3-(4-methoxyphenyl)-4H-chromen-4-one (Intermediate 1): Formononetin (3.0 g, 11.0 mmol), anhydrous K2CO3 (4.5 g, 32.9 mmol) and 80 mL of ethanol were added to a 250 mL three-necked flask in sequence. The temperature was slowly raised to 80°C and stirred for 0.5 h. Dibromopropane (54.8 mmol) was added dropwise and reacted for 6 to 10 h. The reaction progress was monitored by TLC. After the reaction was completed, a large amount of ethanol was removed by rotary evaporation under reduced pressure. The reaction system was dispersed with 500 mL of ice water to precipitate a large amount of white solid. The solid was filtered, washed several times with water and petroleum ether, and dried to obtain a white solid. The obtained white solid was slurried with 60 mL of a solvent of petroleum ether / ethyl acetate = 3:1 (V / V) overnight and filtered to obtain Intermediate 1 with a yield of 86%.

[0073] (2) Synthesis of tert-butyl-(1-(4-(3-(4-methoxyphenyl)-4-oxo-4H-chromen-7-yl)oxy)propyl)piperidin-4-yl)carbamate (Intermediate 2): 4-boc-aminopiperidine (1.54 g, 7.71 mmol), anhydrous K2CO3 (2.66 g, 19.27 mmol), a catalytic amount of KI, and 100 mL of acetonitrile were added sequentially to a 250 mL three-necked round-bottom flask. The mixture was stirred at room temperature for 0.5 h and then slowly heated to 80°C. Intermediate 1 (1.5 g, 3.85 mmol) was dissolved in CH3CN (20 mL) and slowly added to the three-necked round-bottom flask. The reaction was allowed to react for 8 to 10 h, and the reaction progress was monitored by TLC. After the reaction was completed, most of the solvent was removed by rotary evaporation under reduced pressure, and the reaction mixture was then transferred to 300 mL of ice water, whereupon a large amount of white solid precipitated. After filtration, drying, and column chromatography (dichloromethane / methanol = 25:1, V / V), intermediate 2 was obtained with a yield of 62%.

[0074] (3) Synthesis of 7-(3-(4-aminopiperidin-1-yl)propoxy)-3-(4-methoxyphenyl)-4H-chromen-4-one (Intermediate 3): Intermediate 2 (1 g, 1.97 mmol) and 50 mL of methanol were mixed and placed in a 100 mL single-necked round-bottom flask. After the mixture was heated to 60°C and dissolved, 5 mL of 15% hydrochloric acid methanol solution was slowly added dropwise. The reaction was allowed to react for 1 to 2 h, and the reaction progress was monitored by TLC. After the reaction was completed, a large amount of solvent methanol was removed by rotary evaporation under reduced pressure. Then, the reaction system was dispersed into 100 mL of ice water and stirred vigorously to fully dissolve the organic hydrochloride. Subsequently, ethyl acetate was added and extracted three times (3×20 mL). The organic phase was discarded to remove organic impurities. The residual phase was adjusted to pH 9 to 10 with 5 wt% NaHCO3 solution, allowed to stand for 1 h, and extracted three times with dichloromethane. The organic phases were combined, dried over anhydrous Na2SO4, and then rotary evaporated under reduced pressure to obtain Intermediate 3.

[0075] (4) Synthesis of N-(1-(3-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)propyl)piperidin-4-yl)-4-methylbenzenesulfonamide (Compound M1): Intermediate 3 (0.5 g, 1.12 mmol), anhydrous K2CO3 (0.48 g, 3.36 mmol) and 20 mL of CH2Cl2 were placed in a 50 mL single-necked round-bottom flask in sequence. The mixture was stirred in an ice bath for 0.5 h. 4-Methanesulfonyl chloride (1.12 mmol) was slowly added and the reaction was allowed to proceed for 0.5 to 1 h. The reaction progress was monitored by TLC. After the reaction was completed, the system was dispersed into 100 mL of ice water and extracted with dichloromethane three times (3×25 mL). The organic phases were combined, dried over anhydrous Na2SO4, and rotary evaporated under reduced pressure to obtain the crude product. Finally, the crude product was dissolved in 20 mL of methanol and recrystallized. Yield: 65%.

[0076] Example 2

[0077] The synthesis of N-(1-(3-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)propyl)piperidin-4-yl)-3-methylbenzenesulfonamide (Compound No. M2) was carried out using the same procedures as in Example 1, except that the 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of 3-methylbenzenesulfonyl chloride. Yield: 67%.

[0078] Example 3

[0079] The synthesis of N-(1-(3-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)propyl)piperidin-4-yl)benzenesulfonamide (Compound No. M3) was carried out using the same procedures as in Example 1, except that the 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equimolar amount of benzenesulfonyl chloride. Yield: 69%.

[0080] Example 4

[0081] The synthesis of 4-methoxy-N-(1-(3-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)propyl)piperidin-4-yl)benzenesulfonamide (Compound No. M4) was carried out using the same procedures as in Example 1, except that an equal molar amount of 4-methoxybenzenesulfonyl chloride was used in place of 4-methylbenzenesulfonyl chloride in step (4). Yield: 94%.

[0082] Example 5

[0083] The synthesis of 4-fluoro-N-(1-(3-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)propyl)piperidin-4-yl)benzenesulfonamide (Compound No. M5) was carried out using the same procedures as in Example 1, except that 4-methylbenzenesulfonyl in step (4) was replaced with an equimolar amount of 4-fluorobenzenesulfonyl chloride. Yield: 55%.

[0084] Example 6

[0085] The synthesis of 3-fluoro-N-(1-(3-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)propyl)piperidin-4-yl)benzenesulfonamide (Compound No. M6) was carried out using the same procedures as in Example 1, except that 4-methylbenzenesulfonyl in step (4) was replaced with an equimolar amount of 3-fluorobenzenesulfonyl chloride. Yield: 64%.

[0086] Example 7

[0087] The synthesis of 4-chloro-N-(1-(3-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)propyl)piperidin-4-yl)benzenesulfonamide (Compound No. M7) was carried out using the same procedures as in Example 1, except that 4-methylbenzenesulfonyl in step (4) was replaced with an equimolar amount of 4-chlorobenzenesulfonyl chloride. Yield: 64%.

[0088] Example 8

[0089] The synthesis of 3-chloro-N-(1-(3-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)propyl)piperidin-4-yl)benzenesulfonamide (Compound No. M8) was carried out using the same procedures as in Example 1, except that 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of 3-chlorobenzenesulfonyl chloride. Yield: 67%.

[0090] Example 9

[0091] The synthesis of 4-bromo-N-(1-(3-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)propyl)piperidin-4-yl)benzenesulfonamide (Compound No. M9) was carried out using the same procedures as in Example 1, except that 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of 4-bromobenzenesulfonyl chloride. Yield: 83%.

[0092] Example 10

[0093] The synthesis of 3-bromo-N-(1-(3-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)propyl)piperidin-4-yl)benzenesulfonamide (Compound No. M10) was carried out using the same procedures as in Example 1, except that 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of 3-bromobenzenesulfonyl chloride. Yield: 73%.

[0094] Example 11

[0095] The synthesis of N-(1-(3-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)propyl)piperidin-4-yl)-4-nitrobenzenesulfonamide (Compound No. M11) was carried out using the same procedures as in Example 1, except that an equal molar amount of 4-nitrobenzenesulfonyl chloride was used in place of 4-methylbenzenesulfonyl chloride in step (4). Yield: 54%.

[0096] Example 12

[0097] The synthesis of N-(1-(3-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)propyl)piperidin-4-yl)-4-(trifluoromethyl)benzenesulfonamide (Compound No. M12) was carried out using the same procedures as in Example 1, except that 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of 4-trifluoromethylbenzenesulfonyl chloride. Yield: 64%.

[0098] Example 13

[0099] The synthesis of N-(1-(3-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)propyl)piperidin-4-yl)pyridine-3-sulfonamide (Compound No. M13) was carried out using the same procedures as in Example 1, except that 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of pyridine-3-sulfonyl chloride. Yield: 52%.

[0100] Example 14

[0101] The synthesis of N-(1-(3-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)propyl)piperidin-4-yl)thiophene-2-sulfonamide (Compound No. M14) was carried out using the same procedures as in Example 1, except that 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of thiophene-2-sulfonyl chloride. Yield: 58%.

[0102] Example 15

[0103] The synthesis of 3,5-dichloro-N-(1-(3-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)propyl)piperidin-4-yl)benzenesulfonamide (Compound No. M15) was carried out using the same procedures as in Example 1, except that 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of 3,5-dichlorobenzenesulfonyl chloride. Yield: 54%.

[0104] Example 16

[0105] The synthesis of 4-(tert-butyl)-N-(1-(3-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)propyl)piperidin-4-yl)benzenesulfonamide (Compound No. M16) was carried out using the same procedures as in Example 1, except that 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of 4-tert-butylbenzenesulfonyl chloride. Yield: 66%.

[0106] Example 17

[0107] The synthesis of N-(1-(4-((3-(4-methoxyphenyl)-4-oxyl-4H-chromen-7-yl)oxy)butyl)piperidin-4-yl)-4-methylbenzenesulfonamide (compound number M17) comprises the following steps:

[0108] (1) Synthesis of 7-(3-bromobutoxy)-3-(4-methoxyphenyl)-4H-chromen-4-one: The same as step 1 of Example 1, except that 1,3-dibromopropane was replaced with an equal amount of 1,4-dibromobutane.

[0109] (2) Synthesis of tert-butyl-(1-(4-(3-(4-methoxyphenyl)-4-oxo-4H-chromen-7-yl)oxy)butyl)piperidin-4-yl)carbamate: The same as step 2 of Example 1, except that 7-(3-bromopropyloxy)-3-(4-methoxyphenyl)-4H-chromen-4-one was replaced with an equal amount of 7-(3-bromobutyloxy)-3-(4-methoxyphenyl)-4H-chromen-4-one.

[0110] (3) Preparation of 7-(3-(4-aminopiperidin-1-yl)butoxy)-3-(4-methoxyphenyl)-4H-chromen-4-one: The same as step 3 of Example 1, except that 7-(3-(4-aminopiperidin-1-yl)propoxy)-3-(4-methoxyphenyl)-4H-chromen-4-one was replaced with an equal amount of 7-(3-(4-aminopiperidin-1-yl)butoxy)-3-(4-methoxyphenyl)-4H-chromen-4-one.

[0111] (4) Synthesis of N-(1-(4-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)butyl)piperidin-4-yl)-4-methylbenzenesulfonamide: The same as step 4 of Example 1, except that 7-(3-(4-aminopiperidin-1-yl)propoxy)-3-(4-methoxyphenyl)-4H-chromen-4-one was replaced with an equal amount of 7-(3-(4-aminopiperidin-1-yl)butoxy)-3-(4-methoxyphenyl)-4H-chromen-4-one, with a yield of 52%.

[0112] Example 18

[0113] The synthesis of N-(1-(4-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)butyl)piperidin-4-yl)-3-methylbenzenesulfonamide (Compound No. M18) was carried out using the same procedures as in Example 17, except that 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of 3-methylbenzenesulfonyl chloride. Yield: 55%.

[0114] Example 19

[0115] The synthesis of N-(1-(4-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)butyl)piperidin-4-yl)benzenesulfonamide (Compound No. M19) was carried out using the same procedures as in Example 17, except that the 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equimolar amount of benzenesulfonyl chloride. Yield: 70%.

[0116] Example 20

[0117] The synthesis of 4-methoxy-N-(1-(4-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)butyl)piperidin-4-yl)benzenesulfonamide (Compound No. M20) was carried out using the same procedures as in Example 17, except that 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of 4-methoxybenzenesulfonyl chloride. Yield: 67%.

[0118] Example 21

[0119] The synthesis of 4-fluoro-N-(1-(4-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)butyl)piperidin-4-yl)benzenesulfonamide (Compound No. M21) was carried out using the same procedures as in Example 17, except that 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of 4-fluorobenzenesulfonyl chloride. Yield: 48%.

[0120] Example 22

[0121] The synthesis of 3-fluoro-N-(1-(4-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)butyl)piperidin-4-yl)benzenesulfonamide (Compound No. M22) was carried out using the same procedures as in Example 17, except that 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of 3-fluorobenzenesulfonyl chloride. Yield: 87%.

[0122] Example 23

[0123] The synthesis of 4-chloro-N-(1-(4-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)butyl)piperidin-4-yl)benzenesulfonamide (Compound No. M23) was carried out using the same procedures as in Example 17, except that 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of 4-chlorobenzenesulfonyl chloride. Yield: 55%.

[0124] Example 24

[0125] The synthesis of 3-chloro-N-(1-(4-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)butyl)piperidin-4-yl)benzenesulfonamide (Compound No. M24) was carried out using the same procedures as in Example 17, except that 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of 3-chlorobenzenesulfonyl chloride. Yield: 73%.

[0126] Example 25

[0127] The synthesis of 4-bromo-N-(1-(4-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)butyl)piperidin-4-yl)benzenesulfonamide (Compound No. M25) was carried out using the same procedures as in Example 17, except that 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of 4-bromobenzenesulfonyl chloride. Yield: 64%.

[0128] Example 26

[0129] The synthesis of 3-bromo-N-(1-(4-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)butyl)piperidin-4-yl)benzenesulfonamide (Compound No. M26) was carried out using the same procedures as in Example 17, except that 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of 3-bromobenzenesulfonyl chloride. Yield: 53%.

[0130] Example 27

[0131] The synthesis of N-(1-(4-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)butyl)piperidin-4-yl)-4-nitrobenzenesulfonamide (Compound No. M27) was carried out using the same procedures as in Example 17, except that 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equimolar amount of 4-nitrobenzenesulfonyl chloride. Yield: 58%.

[0132] Example 28

[0133] The synthesis of N-(1-(4-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)butyl)piperidin-4-yl)-4-(trifluoromethyl)benzenesulfonamide (Compound No. M28) was carried out using the same procedures as in Example 17, except that the 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of 4-trifluoromethylbenzenesulfonyl chloride. Yield: 74%.

[0134] Example 29

[0135] The synthesis of N-(1-(4-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)butyl)piperidin-4-)pyridine-3-sulfonamide (Compound No. M29) was carried out using the same procedures as in Example 17, except that 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of pyridine-3-sulfonyl chloride. Yield: 73%.

[0136] Example 30

[0137] Synthesis of N-(1-(4-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)butyl)piperidin-4-yl)thiophene-2-sulfonamide (Compound No. M30, the steps are the same as Example 17, except that 4-methylbenzenesulfonyl chloride in step (4) is replaced by an equimolar amount of thiophene-2-sulfonyl chloride. Yield: 72%.

[0138] Example 31

[0139] The synthesis of 3,5-dichloro-N-(1-(4-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)butyl)piperidin-4-yl)benzenesulfonamide (Compound No. M31) was carried out using the same procedures as in Example 17, except that 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of 3,5-dichlorobenzenesulfonyl chloride. Yield: 66%.

[0140] Example 32

[0141] The synthesis of 4-(tert-butyl)-N-(1-(4-((3-(4-methoxyphenyl)-4-oxy-4H-chromen-7-yl)oxy)butyl)piperidin-4-yl)benzenesulfonamide (Compound No. M32) was carried out using the same procedures as in Example 17, except that 4-methylbenzenesulfonyl chloride in step (4) was replaced with an equal molar amount of 4-tert-butylbenzenesulfonyl chloride. Yield: 64%.

[0142] Example 33

[0143] The synthesis of 7-(3-(4-aminopiperidin-1-yl)propoxy)-3-(4-methoxyphenyl)-4H-chromen-4-one hydrochloride (compound number M33) comprises the following steps:

[0144] (1) to (3) are the same as (1) to (3) in Example 1.

[0145] (4) Synthesis of 7-(3-(4-aminopiperidin-1-yl)propoxy)-3-(4-methoxyphenyl)-4H-chromen-4-one hydrochloride: Intermediate 3 (0.5 g, 1.12 mmol) and 25 mL of methanol were added to a 100 mL single-necked round-bottom flask and gradually heated to 60°C. After the intermediate 3 was completely dissolved, 2 mL of 37% hydrochloric acid was added dropwise and stirred for 1-2 h. After salification, 2 / 3 of the volume of methanol was removed by rotary evaporation under reduced pressure, and 20 mL of ethyl acetate was added. The mixture was stirred vigorously for 1-2 h, and a large amount of insoluble white solid precipitated. The target compound was then obtained by filtration and drying. The yield was 84%.

[0146] Example 34

[0147] The synthesis of 7-(3-(4-aminopiperidin-1-yl)butoxy)-3-(4-methoxyphenyl)-4H-chromen-4-one hydrochloride (compound number M34) comprises the following steps:

[0148] (1) to (3) are the same as (1) to (3) in Example 17.

[0149] (4) Same as Example 33, except that 7-(3-(4-aminopiperidin-1-yl)propoxy)-3-(4-methoxyphenyl)-4H-chromen-4-one in step (4) was replaced with an equal molar amount of 7-(3-(4-aminopiperidin-1-yl)butoxy)-3-(4-methoxyphenyl)-4H-chromen-4-one. Yield: 87%.

[0150] The physicochemical properties and mass spectrometry data of the formononetin derivatives containing a piperidine skeleton synthesized in Examples M1 to M34 are shown in Table 1, and the nuclear magnetic resonance (NMR) data are shown in Table 2.

[0151] Table 1. Physicochemical properties of target compounds and their mass spectrometry analysis data.

[0152]

[0153] Table 2. NMR spectral data of target compounds.

[0154]

[0155]

[0156]

[0157]

[0158]

[0159]

[0160] Test Example 1 Anti-plant pathogenic bacteria activity test

[0161] Test method:

[0162] Turbidimetric testing was used to evaluate the in vitro activity of common plant diseases including Xanthoceras oryzae (Xoo), Xanthoceras citri (Xac), Xanthoceras angularis (Xcm), Xanthoceras kiwifruit (Psa), Psoralea corylifolia (Pcb), Xanthoceras melanocarpa (Ac), and Ralstonia spp. (Rs). The commercial pesticides thiophanate-methyl (TC) and zinc thiazole (ZT) were used as positive controls. The specific steps are as follows:

[0163] (1) Inoculate the plant pathogenic bacteria to be tested into NA medium using the streak method and then culture in a constant temperature incubator at 28°C until uniform single colonies grow. Select a single colony and place it in sterilized NB liquid medium. Incubate the culture in a constant temperature shaker at 28°C and 180 rpm until the logarithmic growth phase is reached.

[0164] (2) Prepare 25000 μg / mL stock solution 1 for the sample and control drugs respectively. Accurately measure 80 μL of stock solution 1 in 3.92 mL of sterile deionized water containing 0.1% Tween-20 and shake thoroughly to prepare stock solution 2 for testing. Pipette 1 mL of stock solution 2 into three sterilized test tubes containing 4 mL of NB culture medium. For the control group, add 1% DMSO to the test tube. Pipette 200 μL from each test tube and measure its OD value. 595 The value is the OD value of sterile culture medium 595 Then, 48 μL of the test bacteria was inoculated into each test tube and cultured in a constant temperature shaker at 28°C and 180 rpm for 12 to 48 hours. When the turbidity value of the control group grew to 0.6 to 0.8, the OD value of each test tube was measured. 595The inhibition rate of the tested compounds was calculated according to the following formula. The results are shown in Table 3.

[0165] (3) Correction of OD 595 Value = OD of culture medium containing bacteria 595 Value - sterile culture medium OD 595 value

[0166] Inhibition rate (%) = (corrected control group culture medium bacterial solution OD 595 - Correction of OD of drug-containing culture medium 595 )×100% / corrected control group culture medium bacterial solution OD 595 value.

[0167] (4) The results of the bioactivity test against plant pathogenic bacteria are shown in Table 3.

[0168] Table 3. In vitro inhibitory activity of M1-M34 against seven plant bacteria at 100 μg / mL.

[0169]

[0170]

[0171] As shown in Table 3, compounds M1, M4, and M8 exhibited inhibition rates of 82.0%, 82.7%, and 90.9% against Xoo at 100 μg / mL, respectively. These rates were higher than those of the control agent thiophanate-methyl (TC, 70.3%) and comparable to zinc thiazole (ZT, 82.3%). Compounds M2, M5, M6, and M8 exhibited significant inhibition against Xac at 100 μg / mL, with inhibition rates of 85.3%, 86.7%, 89.6%, and 87.2%, respectively, exceeding those of the control agents TC (55.6%) and ZT (70.2%). Furthermore, inspired by the excellent water solubility of organic hydrochlorides, compound M33 was designed and synthesized, achieving 100% inhibitory activity against four plant bacteria (Xoo, Xac, Xcm, and Psa), and compound M34 achieved 100% inhibitory activity against five plant bacteria (Xoo, Xac, Xcm, Psa, and Ac).

[0172] The above experimental activity data show that the piperidine skeleton-containing thorny antler derivatives have a good inhibitory effect on plant pathogenic bacteria. Among them, some target compounds show excellent activity against plant pathogens and can be used as potential anti-plant pathogen drugs with good application prospects.

[0173] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A formononetin derivative containing a piperidine skeleton having the structural formula shown below: In the formula, n is an integer of 2 to 6, and R is independently selected from unsubstituted or optionally substituted phenyl, pyridyl and thienyl.

2. The formononetin derivative containing a piperidine skeleton according to claim 1, characterized in that The optionally substituted phenyl group contains one or more halogens, one or more C1-C6 alkyl groups, one or more C1-C6 substituted alkyl groups, one or more C1-C6 alkoxy groups, one or more nitro groups, one or more trifluoromethyl groups, or one or more tert-butyl groups at the ortho, meta, and para positions on the benzene ring; the pyridine and thienyl groups are unsubstituted pyridyl and thienyl groups.

3. A method for preparing the formononetin derivative containing a piperidine skeleton as claimed in claim 1 or 2, characterized in that: The following steps are involved: (1) Using formononetin and dibromoalkane as raw materials, heating the reaction in a solvent containing an alkaline catalyst, adding ice water after the reaction to precipitate the product, filtering, and removing impurities from the filter residue to obtain intermediate 1; The structural formula of the dibromoalkane is: Wherein, n is an integer from 2 to 6; The structural formula of the intermediate 1 is: Wherein, n is an integer from 2 to 6; (2) Using intermediate 1 and 4-boc-aminopiperidine as raw materials, heating the reaction in a solvent under alkaline conditions, adding ice water after the reaction is completed to precipitate the product, filtering, washing, drying, and column chromatography to obtain intermediate 2; The structural formula of the intermediate 2 is: Wherein, n is an integer from 2 to 6; (3) Using intermediate 2 as raw material, the BOC protection was removed under heating conditions to obtain intermediate 3; The structural formula of the intermediate 3 is: Wherein, n is an integer from 2 to 6; (4) using intermediate 3 and substituted sulfonyl chloride as raw materials, reacting in an ice bath, and after the reaction, purifying the crude product to obtain the formononetin derivative containing piperidine sulfonamide; The structural formula of the substituted sulfonyl chloride is: wherein R is independently selected from unsubstituted or optionally substituted phenyl, pyridyl and thienyl; (5) Using intermediate 3 and 37% HCl solution as raw materials, an amine salt reaction was carried out under heating conditions to prepare the above-mentioned formononetin derivative containing piperidine hydrochloride.

4. The preparation method according to claim 3, wherein: The molar ratio of formononetin to dibromoalkane in step (1) is 10.0:(50.0-100.0); the temperature of the heating reaction is 60-90°C and the time is 4-10 hours; the alkaline catalyst is anhydrous potassium carbonate; and the impurity removal step comprises: washing the filter residue with water and petroleum ether in sequence, then beating, standing, filtering, and completing washing.

5. The preparation method according to claim 3, wherein: The molar ratio of the intermediate 1, 4-boc-aminopiperidine and anhydrous potassium carbonate in step (2) is 3.85: (3.85-19.25): (19.25-77.0); the temperature of the heating reaction is 50-90° C. and the time is 8-24 hours; the solution used for the column chromatography is a mixture of dichloroethane and methanol in a volume ratio of 25:

1.

6. The preparation method according to claim 3, wherein: The step of removing the boc protection in step (3) comprises: dissolving the intermediate 2 in methanol, heating to 40-80° C., adding dropwise a 10-37% HCl methanol solution by mass, reacting for 1-4 hours, and removing the boc protection.

7. The preparation method according to claim 3, wherein: In step (4), the molar ratio of the intermediate 3, the substituted sulfonyl chloride and potassium carbonate is 1.0:(0.5-1.5):(1.0-3.0); the purification method is to use methanol for recrystallization.

8. The preparation method according to claim 3, wherein: The molar ratio of the intermediate 3 and the 37% HCl solution in step (5) is 1.0:(10.0-30.0).

9. Use of the formononetin derivative containing a piperidine skeleton as claimed in claim 1 or 2 in the preparation of an agent for inhibiting plant pathogenic bacteria.

10. The use according to claim 9, characterized in that: The plant pathogenic bacteria are one or more of oryzae bacteria (Xoo), citrus canker (Xac), mango bacterial leaf spot (Xcm), kiwifruit canker (Psa), potato soft rot (Pcb), melon fruit spot (Ac), and tomato bacterial wilt (Rs).

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