Oxazole ring-containing and magnolol-antimicrobial peptide mimic conjugates, their preparation methods and antimicrobial applications

Abstract

This invention discloses a series of oxazole-ring-containing honokiol-antimicrobial peptide mimic conjugates, their preparation methods, and antimicrobial applications. This series of compounds uses natural products and honokiol as leads, and after structural optimization of the para-phenolic hydroxyl group, a hydrophilic small-molecule amine fragment is introduced at the ortho-phenolic hydroxyl group, thereby preparing a series of oxazole-ring-containing honokiol-antimicrobial peptide mimic conjugates, the general structural formula of which is shown in formula (I). This series of compounds exhibits strong in vivo and in vitro antimicrobial activity against Staphylococcus aureus ATCC 29213 and clinically isolated methicillin-resistant Staphylococcus aureus (MRSA). Through structural optimization, this invention enhances their water solubility and antimicrobial activity, and also exhibits low in vivo and in vitro toxicity, hemolytic activity, and low drug resistance. Therefore, these oxazole-ring-containing honokiol-antimicrobial peptide mimic conjugates have the potential to be further developed into novel antimicrobial drugs.

Description

Technical Field

[0001] This invention belongs to the field of medicinal chemistry technology, specifically relating to oxazole ring-containing magnolol-antimicrobial peptide mimic conjugates, their preparation methods, and antimicrobial applications. Background Technology

[0002] The overuse and misuse of antibiotics have led to the continuous emergence and widespread spread of multidrug-resistant bacteria. Antibiotic resistance has become a global public health problem that endangers human health (Song M, Liu Y, Huang X, et al. Abroad-spectrum antibiotic adjuvant reverses multidrug-resistant Gram-negative pathogens[J]. Nature Microbiology, 2020, 5(8): 1040-1050.). Methicillin-resistant Staphylococcus aureus (MRSA), as a novel drug-resistant strain, has developed resistance to almost all existing antimicrobial agents, such as penicillins, tetracyclines, quinolones, aminoglycosides, clindamycin, and daptomycin (McAdam PR, Templeton KE, Edwards GF, et al. Molecular tracing of the emergence, adaptation, and transmission of hospital-associated methicillin-resistant Staphylococcus aureus[J]. Proceedings of the National Academy of Sciences, 2012, 109(23): 9107-9112.). Therefore, there is an urgent need to develop novel antimicrobial agents with potential therapeutic effects against MRSA infection.

[0003] Antimicrobial peptides (AMPs) have attracted widespread interest due to their broad-spectrum activity and low resistance to antibiotics. Unlike traditional antibiotics that target only one site, most AMPs can kill bacteria by disrupting membrane integrity, causing osmotic imbalance, inhibiting protein synthesis, and interacting with nucleic acids. Therefore, AMPs can be considered as candidate drugs for treating drug-resistant bacterial strains. However, the poor stability, weak antimicrobial activity, and high cost of AMPs severely limit their clinical application (Ghosh C, Sarkar P, Issa R, et al. Alternatives to Conventional Antibiotics in the Era of Antimicrobial Resistance[J]. Trends in Microbiology, 2019, 27(4):323-338.). Honokiol is a bisphenol compound widely found in Magnolia officinalis Rehd. et Wils. and Magnolia officinalis var. biloba Rehd. et Wils., belonging to the Magnoliaceae family. It possesses various biological activities, including anti-inflammatory, antioxidant, and antibacterial properties (Cheng CH, Zhang QW, Yang YE, et al. Honokiol: A naturally occurring lignan with pleiotropic bioactivities[J]. Chinese Journal of Natural Medicines, 2021, 19(7):481-490.). However, due to its limited water solubility and poor bioavailability, honokiol is difficult to directly function as an antibacterial drug. Summary of the Invention

[0004] Objective of the Invention: To address the aforementioned technical problems, this invention provides an oxazole-ring-containing honokiol-antimicrobial peptide mimic conjugate, its preparation method, and its antimicrobial application. This invention adopts a complementary approach, drawing on the structural and functional characteristics of antimicrobial peptides. Using natural products and honokiol as the parent compound, a nitrogen-containing heterocycle is introduced through structural modification and then linked to a cationic antimicrobial peptide mimic fragment. The aim is to obtain a highly active, low-toxicity oxazole-ring-containing honokiol-antimicrobial peptide mimic conjugate. The resulting oxazole-ring-containing honokiol-antimicrobial peptide mimic conjugate exhibits significant antibacterial effects against Staphylococcus aureus (S. aureus) ATCC 29213, clinically isolated MRSA strains, and the MRSA standard strain N315, while also solving the problem of poor toxicity.

[0005] Technical Solution: To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0006] The structure of the oxazole ring-containing magnolol-antimicrobial peptide mimic conjugate is shown in formula (I):

[0007]

[0008] R1, R2, and R3 are independently selected from H, halogens, C1-C3 alkoxy groups, or CF3.

[0009] As a preferred embodiment, R1, R2, and R3 are one of the following combinations:

[0010] (1) R1=R2=R3=H; (2) R1=R2=H, R3=2-F; (3) R1=R2=H, R3=4-F;

[0011] (4) R1=R2=H, R3=2-Cl; (5) R1=R2=H, R3=4-Cl; (6) R1=R2=H, R3=2-Br;

[0012] (7) R1=R2=H, R3=3-Br; (8) R1=R2=H, R3=4-Br; (9) R1=H, R2=2-F, R3=4-Cl;

[0013] (10) R1=H, R2=2-F, R3=5-Br; (11) R1=H, R2=3-F, R3=4-F;

[0014] (12) R1=H, R2=3-F, R3=4-Cl; (13) R1=H, R2=2-Cl, R3=4-F;

[0015] (14) R1=H, R2=3-Cl, R3=4-F; (15) R1=H, R2=2-Cl, R3=3-Cl;

[0016] (16) R1=H, R2=2-Cl, R3=4-Cl; (17) R1=H, R2=2-Cl, R3=6-Cl;

[0017] (18) R1=H, R2=3-Cl, R3=4-Cl; (19) R1=H, R2=3-Cl, R3=5-Cl;

[0018] (20) R1=H, R2=2-Br, R3=4-Cl; (21) R1=H, R2=3-Br, R3=4-F;

[0019] (22) R1=H, R2=3-Br, R3=4-Cl; (23) R1=H, R2=2-Br, R3=4-Br;

[0020] (24) R1=H, R2=3-Br, R3=5-Br; (25) R1=3-F, R2=4-F, R3=5-F;

[0021] (26) R1=R2=H, R3=3-OCH3; (27) R1=R2=H, R3=4-OCH3; (28) R1=R2=H, R3=4-CF3.

[0022] The specific selections above represent compounds 1-28 in the following examples (each compound corresponds to a combination of the same serial numbers mentioned above); 2-F indicates that the F substituent is located at the 2 position of the benzene ring, and other abbreviations follow the same pattern.

[0023] The present invention also provides a method for preparing the oxazole ring-containing and magnolol-antimicrobial peptide mimic conjugate, comprising the following steps:

[0024] (1) Using magnolol as a substrate, react with iodine to convert the ortho-phenolic hydroxyl group and propenyl group into an oxygen-containing five-membered ring to obtain intermediate 2.

[0025] (2) Intermediate 2 reacts with concentrated nitric acid to introduce a nitro group to synthesize intermediate 3;

[0026] (3) Intermediate 3 reacts with a reducing agent to reduce the nitro group to an amino group to obtain intermediate 4;

[0027] (4) Under the action of a catalyst, intermediate 4 undergoes ring-opening of an oxygen-containing five-membered ring to generate phenolic hydroxyl and propenyl groups, thus obtaining intermediate 5;

[0028] (5) Intermediate 5 reacts with benzaldehyde containing different substituents to generate intermediate 6;

[0029] (6) Intermediate 6 reacts with a dehydrogenating agent to generate intermediate 7, which contains a nitrogen-containing heterocycle;

[0030] (7) Intermediate 7 reacts with 1,3-dibromopropane under alkaline conditions to generate intermediate 8;

[0031] (8) Intermediate 8 then reacts with small molecule peptide mimic 9 to generate the oxazole ring-containing honokiol-antimicrobial peptide mimic conjugate, as shown in the following reaction formula:

[0032]

[0033]

[0034] Wherein, R1, R2 and R3 are as described in claim 1 or 2.

[0035] As a specific implementation plan, in step (1), the molar ratio of the reaction between magnolol and iodine is 1:(1.0-1.2), the reaction temperature is 45-55℃, and the reaction solvent is ethanol and ultrapure water in a ratio of 9:1-7:3.

[0036] As a specific implementation plan, in step (2), the reaction molar ratio of intermediate 2 to concentrated nitric acid is 1:(2.5-3.5), the reaction temperature is 0±5℃, and the reaction solvent is dichloromethane.

[0037] As a specific implementation scheme, in step (3), the reducing agent is selected from stannous chloride dihydrate; the molar ratio of intermediate 3 to reducing agent is 1:(9-11), the reaction temperature is 75-80℃, and the reaction solvent is ethyl acetate;

[0038] As a specific implementation scheme, in step (4), the catalyst is selected from zinc; the molar ratio of intermediate 4 to catalyst is 1:(4-6), the reaction temperature is 75-80℃, and the reaction solvent is anhydrous ethanol.

[0039] As a specific implementation plan, in step (5), the molar ratio of intermediate 5 to benzaldehyde containing different substituents is 1:(2.5-3.5), the reaction temperature is 40-50℃, and the reaction solvent is methanol;

[0040] As a specific implementation scheme, in step (6), the dehydrogenating agent is selected from DDQ; the molar ratio of intermediate 6 to the dehydrogenating agent is 1:(1.0-1.2), the reaction temperature is room temperature, and the reaction solvent is dichloromethane;

[0041] As a specific implementation plan, in step (7), the molar ratio of intermediate 7 to 1,3-dibromopropane is 1:(2.5-3.5), the reaction temperature is 45-55℃, and the reaction solvent is anhydrous acetone.

[0042] As a specific implementation scheme, in step (8), the preparation method of the small molecule peptide mimic 9 includes the following steps: bromoacetyl bromide reacts with n-butylamine under alkaline conditions to generate bromoacetamide, and then bromoacetamide continues to react with dimethylamine under alkaline conditions to generate the small molecule peptide mimic:

[0043]

[0044] As a specific implementation plan, in step (8), the molar ratio of intermediate 8 to small molecule peptide mimic 9 is 1:(2.5-3.5), the reaction temperature is 75-85℃, and the reaction solvent is anhydrous ethanol.

[0045] Furthermore, as a preferred option:

[0046] In step (1), the molar ratio of magnolol to iodine is 1:1.1, the reaction temperature is 50°C, and the reaction solvent is ethanol and ultrapure water in a 9:1 ratio.

[0047] In step (2), the reaction molar ratio of intermediate 2 to concentrated HNO3 is 1:3, the reaction temperature is 0℃, and the reaction solvent is dichloromethane.

[0048] In step (3), the molar ratio of intermediate 3 to stannous chloride dihydrate is 1:10, the reaction temperature is 77°C, and the reaction solvent is ethyl acetate.

[0049] In step (4), the molar ratio of intermediate 4 to zinc is 1:5, the reaction temperature is 78°C, and the reaction solvent is anhydrous ethanol.

[0050] In step (5), the molar ratio of intermediate 5 to various substituted benzaldehydes is 1:3, the reaction temperature is 45°C, and the reaction solvent is methanol.

[0051] In step (6), the molar ratio of intermediate 6 to DDQ is 1:1.1, the reaction temperature is room temperature, and the reaction solvent is dichloromethane.

[0052] In step (7), the molar ratio of intermediate 7 to 1,3-dibromopropane is 1:3, the reaction temperature is 50°C, and the reaction solvent is anhydrous acetone.

[0053] In step (8), the molar ratio of intermediate 8 to small molecule peptide mimic 9 is 1:3, the reaction temperature is 80°C, and the reaction solvent is anhydrous ethanol.

[0054] The preparation method of small molecule peptide mimic 9 is as follows:

[0055]

[0056] The molar ratio of n-butylamine to bromoacetyl bromide is 1:1.5, the base used in the reaction is K2CO3, the reaction temperature is 0℃ to room temperature, the reaction time is 12h, and the reaction solvent is anhydrous dichloromethane; the molar ratio of bromoamide to dimethylamine is 1:1.5, the reaction temperature is room temperature, the reaction time is 12h, and the reaction solvent is anhydrous acetone.

[0057] Finally, this invention provides the use of the oxazole ring-containing and magnolol-antimicrobial peptide mimic conjugate in the preparation of antimicrobial drugs. Preferably, the antimicrobial drug is capable of inhibiting Staphylococcus aureus or methicillin-resistant Staphylococcus aureus. For example, it inhibits Staphylococcus aureus ATCC 29213 and various clinically resistant methicillin-resistant Staphylococcus aureus (MRSA).

[0058] This invention utilizes the structure and function of antimicrobial peptides to design and synthesize a series of oxazole ring-containing and magnolol-antimicrobial peptide mimic conjugates. In these conjugates, the parent structure and magnolol, as hydrophobic portions, facilitate insertion of the compounds into the bacterial phospholipid bilayer membrane, while the hydrophilic cationic portions facilitate interaction with the negatively charged bacterial cell membrane, leading to bacterial death. In vitro antibacterial activity evaluations of all target compounds revealed good in vitro antibacterial activity against *S. aureus* ATCC 29213 and clinically isolated MRSA strains, with MIC ≤ 128 μg / mL. Compound 17, in particular, exhibited the most outstanding in vitro and in vivo anti-MRSA activity, with in vivo antibacterial efficacy equivalent to vancomycin at the same dose. Furthermore, the target compounds possess low hemolytic activity, low in vivo toxicity, and plasma stability. Therefore, these compounds provide inspiration for the research of novel anti-MRSA drugs and have broad application prospects.

[0059] Technical effects: The oxazole ring-containing and magnolol-antimicrobial peptide mimic conjugate prepared by this invention has significant in vitro and in vivo antibacterial effects against S. aureus ATCC 29213 and various clinical MRSA strains, while reducing biotoxicity and having a high yield, and is expected to be further developed into a potential antimicrobial drug for clinical use. Attached Figure Description

[0060] Figure 1 The dynamic bactericidal curve of compound 17 is shown.

[0061] Figure 2 The in vivo blood routine and blood biochemical indices of compound 17.

[0062] Figure 3 The change in bacterial load on mouse skin for compound 17.

[0063] Figure 4 For compound 17 1 H-NMR spectrum.

[0064] Figure 5 For compound 17 13 C-NMR spectrum. Detailed Implementation

[0065] The invention will be further illustrated in detail below through examples.

[0066] Preparation of Intermediate 2 in Example 1

[0067] Magnolol (1 mmol) was dissolved in anhydrous ethanol and ultrapure water in a 9:1 ratio, I2 (1.1 mmol) was added, and the mixture was refluxed and stirred at 50 °C for 6 h. After the reaction was monitored by thin-layer chromatography (TLC), the mixture was extracted, dried over Na2SO4, concentrated under reduced pressure, and the concentrate was purified by column chromatography with petroleum ether and ethyl acetate (12:1) to obtain a pale yellow transparent oily intermediate 2.

[0068] Preparation of intermediate 3 in Example 2

[0069] Intermediate 2 (1 mmol) was dissolved in an appropriate amount of CH2Cl2, and then an appropriate amount of CH3COOH was added. After stirring at 0°C for 5 min, concentrated nitric acid (3 mmol) was slowly added. The reaction was carried out in an ice bath for 1 h. After the reaction was completed by TLC, the reaction solution was mixed with ice water, the pH was adjusted to 7 with saturated Na2CO3 aqueous solution, extracted, dried with Na2SO4, concentrated under reduced pressure, and the concentrate was purified by column chromatography with petroleum ether and ethyl acetate (12:1) to obtain brown oily intermediate 3.

[0070] Preparation of intermediate 4 in Example 3

[0071] Intermediate 3 (1 mmol) was dissolved in an appropriate amount of ethyl acetate by stirring, and then stannous chloride dihydrate (10 mmol) was added. The mixture was refluxed and stirred at 77 °C for 2 h under nitrogen protection. After the reaction was completed by TLC, the pH of the reaction solution was adjusted to 7 with saturated Na2CO3 aqueous solution, filtered, the filtrate was extracted, dried over Na2SO4, and concentrated under reduced pressure to obtain white oily intermediate 4.

[0072] Preparation of intermediate 5 in Example 4

[0073] Intermediate 4 (1 mmol) was dissolved in an appropriate amount of ethanol by stirring, and then zinc powder (5 mmol) and an appropriate amount of CH3COOH were added. The mixture was refluxed at 78 °C for 3 h. After the reaction was completed by TLC, zinc was removed by filtration, and the mixture was concentrated under reduced pressure and purified by column chromatography with petroleum ether and ethyl acetate (2:1) to obtain dark brown solid intermediate 5.

[0074] Preparation of intermediate 6 in Example 5

[0075] Intermediate 5 (1 mmol) was dissolved in methanol solution, and the corresponding benzaldehyde (3 mmol) was added. The mixture was refluxed and stirred at 45 °C for 45 min. After the reaction was completed by TLC, the mixture was concentrated under reduced pressure to obtain dark brown oily intermediate 6.

[0076] Preparation of intermediate 7 in Example 6

[0077] DDQ (1.1 mmol) was added to a CH2Cl2 solution of intermediate 6 (1 mmol), and the mixture was stirred at room temperature for 2 h. After the reaction was completed, the residue was filtered off, and the filtrate was concentrated and purified by preparative thin-layer chromatography (PTLC) to obtain intermediate 7.

[0078] Preparation of intermediate 8 in Example 7

[0079] 1,3-dibromopropane (3 mmol) was added to an acetone solution of intermediate 7 (1 mmol), and the mixture was stirred at 50 °C for 12 h. After the reaction was completed by TLC, K2CO3 was removed by filtration, and the filtrate was concentrated and purified by PTLC to obtain intermediate 8.

[0080] Example 8: Preparation of Small Molecule Peptide Mimics

[0081] K2CO3 (1.5 mmol) was added to a redistilled CH2Cl2 solution of n-butylamine (1 mmol), and bromoacetyl bromide was slowly added under ice bath conditions. After reacting at low temperature for 30 min, the mixture was transferred to room temperature and stirred for 12 h. After the reaction was completed by TLC, the mixture was extracted, dried with Na2SO4, and evaporated under reduced pressure to obtain a pale yellow oily intermediate, bromoacetamide.

[0082] Bromoacetamide (1 mmol) was dissolved in acetone and then 1.5 mmol of anhydrous K2CO3 and dimethylamine aqueous solution were added. The reaction was carried out at room temperature for 12 h. After the reaction was completed by TLC, the mixture was concentrated under reduced pressure, extracted, dried with Na2SO4, concentrated under reduced pressure, and purified by column chromatography with dichloromethane and methanol (20:1) to obtain small molecule peptide mimics.

[0083] Example 9 Compound 1

[0084] Intermediate 8 (1 mmol) was dissolved in anhydrous ethanol, and a small peptide fragment (3 mmol) was added. The mixture was reacted at 80 °C under pressure for 12 h. After the reaction was completed by TLC, the target compound was obtained by preparative thin-layer chromatography (dichloromethane:methanol = 10:1).

[0085] The physicochemical properties of compound 1 are as follows:

[0086] 1) Yellow liquid;

[0087] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0088] Using CDCl3 as the solvent, the peaks were assigned as follows: 1 H NMR (600MHz CDCl3)δ: 1H NMR(600MHz CDC13)δ:8.86(s,1H,-NH-),8.27(d,J=7.8Hz,2H,-Ph),7.78(d,J=9.0Hz,2H,-Ph),7.55(d,J=5.4Hz,4H,-Ph),7.34(s,1H ,-Ph),7.01(d,J=7.8Hz,1H,-Ph),6.13-6.04(m,2H,-CH=),5.19-5.14(m,4H,=CH2),4.73(s,2H,-CH2-),4.23(d,J=4.8Hz ,2H,-CH2-),3.97-3.94(m,2H,-CH2-),3.58(d,J=6.6Hz,2H,-CH2-),3.52(s,2H,-CH2-),3.50(s,6H,-CH3),3.32(q,J=6. 6Hz,2H,-CH2-),2.47(s,1H,-CH2-),1.612-1.576(m,2H,-CH2-),1.417-1.381(m,2H,-CH2-),0.94(t,J=7.2Hz,3H,-CH3); 13 C NMR(150MHz CDCl3)δ:163.3,162.5,155.6,146.8,143.1,137.5,136.9,131.5,128.9,127.9,124.3,124.0,11 8.3,116.1,116.0,111.5,64.2,63.1,52.5,40.3,39.7,34.4,31.0,23.6,20.2,13.7; HRMS(ESI)C 36 H 44 BrN3O3[M+H]calcd=646.6700; found=566.3836.

[0089] Example 10 Compound 2

[0090] Compound 2 was synthesized using the method described in Example 9. The physicochemical properties of compound 2 are as follows:

[0091] 1) Yellow liquid;

[0092] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0093] Using CDCl3 as the solvent, the peaks were assigned as follows: 1HNMR(600MHz CDCl3)δ:8.84(s,1H,-NH-),8.25-8.23(m,1H,-Ph),7.79-7.76(m,2H,-Ph),7.58(s,1H,-Ph),7.53-7.52(m,1H,-Ph),7.37(d,J=1.8Hz ,1H,-Ph),7.31(q,J=7.8Hz,2H,-Ph),6.98(d,J=9.0Hz,1H,-Ph),6.90-6.03(m,2H,-CH=),5.17-5.09(m,4H,=CH2),4.64(s,2H,-CH2-) ,4.20(t,J=10.8Hz,2H,-CH2-),3.94-3.91(m,2H,-CH2-),3.58(d,J=6.6Hz,2H,-CH2-),3.49(d,J=6.0Hz,2H,-CH2-),3.46(d,J=8.4Hz ,6H,-CH3),3.28(d,J=6.6Hz,2H,-CH2-),2.45-2.41(m,2H,-CH2-),1.57(s,2H,-CH2-),1.38(d,J=9Hz,2H,-CH2-),0.91(s,3H,-CH3); 13 C NMR(150MHzCDCl3)δ:162.5,161.7,155.6,146.6,142.7,137.4,136.7,133.1,130.5,130.2,128.7,127.3,125.8,124 .6,124.0,118.5,117.2,117.1,116.2,111.5,64.2,63.0,52.5,40.3,39.6,34.5,30.9,23.6,20.2,13.7; HRMS(ESI)C 36 H 43 BrFN3O3[M+H]calcd=664.6604; found=584.3306.

[0094] Example 11 Compound 3

[0095] Compound 3 was synthesized using the method described in Example 9. The physicochemical properties of compound 3 are as follows:

[0096] 1) Yellow liquid;

[0097] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0098] Using CDCl3 as the solvent, the peaks were assigned as follows:1 H NMR(600MHz CDCl3)δ:8.72(s,1H,-NH-),8.31(s,1H,-Ph),8.25(d,J=4.2Hz,2H,-Ph),7.77-7.73(m,2H,-Ph),7.51(s,1H,-Ph),7. 32(s,1H,-Ph),7.22(s,1H,-Ph),7.00-6.99(m,1H,-Ph),6.09-6.05(m,2H,-CH=),5.17-5.12(m,4H,=CH2),4.61(s,2H ,-CH2-),4.21(d,J=3.0Hz,2H,-CH2-),3.94(s,2H,-CH2-),3.57(s,2H,-CH2-),3.47(s,8H,-CH2-,-CH3),3.26(s,2H, -CH2-),2.44(s,2H,-CH2-),1.55(d,J=6.0Hz,2H,-CH2-),1.36(s,2H,-CH2-),0.91(d,J=4.2Hz,3H,-CH3); HRMS(ESI)C 36 H 43 BrFN3O3[M+H]calcd=664.6604; found=584.3306.

[0099] Example 12 Compound 4

[0100] Compound 4 was synthesized using the method described in Example 9. The physicochemical properties of compound 4 are as follows:

[0101] 1) Yellow liquid;

[0102] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0103] Using CDCl3 as the solvent, the peaks were assigned as follows: 1H NMR(600MHz CDC13)δ:8.771(s,1H,-NH-),8.13(d,J=7.8Hz,1H,-Ph),7.71(d,J=8.4Hz,2H,-Ph),7.50(t,J=7.8Hz,2H,-Ph),7.39-7.34( m,2H,-Ph),7.20(s,1H,-Ph),6.89(d,J=8.4Hz,1H,-Ph),6.00-6.96(m,2H,-CH=),5.10-4.99(m,4H,=CH2),4.62(s,2H,-CH2- ),4.11(d,J=3.6Hz,2H,-CH2-),3.84(d,J=4.8Hz,2H,-CH2-),3.50(d,J=6.0Hz,2H,-CH2-),3.39(s,8H,-CH2-,-CH3),3.21- 3.19(m,2H,-CH2-),2.35(s,2H,-CH2-),1.50(d,J=7.2Hz,2H,-CH2-),1.31-1.29(m,2H,-CH2-),0.84(d,J=6.6Hz,3H,-CH3); 13 C NMR(150MHz CDCl3)δ:161.5,160.3,154.6,145.7,141.5,136.4,135.7,130.9,130.4,129.2,127.6,126.3,126.0,125.2,123. 6,123.1,117.5,115.1,114.8,110.5,63.1,62.0,51.5,39.3,38.6,33.5,29.9,28.7,22.6,19.2,12.7; HRMS(ESI)C 36 H 43 BrClN3O3[M+H]calcd=681.1120; found=600.3009.

[0104] Example 13 Compound 5

[0105] Compound 5 was synthesized using the method described in Example 4. The physicochemical properties of compound 5 are as follows:

[0106] 1) Yellow liquid;

[0107] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0108] Using CDCl3 as the solvent, the peaks were assigned as follows: 1H NMR(600MHz CDCl3)δ:8.87(s,1H,-NH-),8.18-8.16(m,2H,-Ph),7.74-7.72(m,2H,-Ph),7.51-7.49(m,3H,-Ph),7.32(s,1H,-P h),6.99(d,J=7.8Hz,1H,-Ph),6.10-6.02(m,2H,-CH=),5.17-5.12(m,4H,=CH2),4.72(s,2H,-CH2-),4.21(s,2H,-C H2-),3.95(d,J=6.0Hz,2H,-CH2-),3.56(d,J=6.0Hz,2H,-CH2-),3.48(s,8H,-CH2-,-CH3),3.30(d,J=6.6Hz,2H,-C H2-),2.46(s,2H,-CH2-),1.60-1.57(m,2H,-CH2-),1.40-1.37(m,2H,-CH2-),0.93-0.90(m,3H,-CH3); HRMS(ESI)C 36 H 43 BrClN3O3[M+H]calcd=681.1120; found=600.3000.

[0109] Example 14 Compound 6

[0110] Compound 6 was synthesized using the method described in Example 4. The physicochemical properties of compound 6 are as follows:

[0111] 1) Yellow liquid;

[0112] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0113] Using CDCl3 as the solvent, the peaks were assigned as follows: 1H NMR(600MHz CDCl3)δ:8.87(s,1H,-NH-),8.14(dd,J=7.8Hz,1.2Hz,1H,-Ph),7.80-7.77(m,3H,-Ph),7.59(d,J=1.2Hz,1H,-Ph),7.48-7.45(m,1H,- Ph),7.38-7.35(m,2H,-Ph),6.96(d,J=9.0Hz,1H,-Ph),6.09-6.01(m,2H,-CH=),5.18-5.05(m,4H,=CH2),4.71(s,2H,-CH2-),4.20-4.1 82(m,2H,-CH2-),3.92-3.89(m,2H,-CH2-),3.58(d,J=7.2Hz,2H,-CH2-),3.47(s,2H,-CH2-),3.45(s,8H,-CH3),3.31-3.27(m,2H,-CH2 -),2.43(dd,J=10.2Hz,5.4Hz,2H,-CH2-),1.58(t,J=7.2Hz,2H,-CH2-),1.38(dd,J=15Hz,7.2Hz,2H,-CH2-),0.93-0.901(m,3H,-CH3); 13 C NMR(150MHzCDCl3)δ:162.4,161.9,155.6,146.8,142.6,137.4,136.0,134.7,132.3,132.1,130.4,128.5,127.5,124 .7,124.2,121.7,118.6,116.2,115.8,111.5,64.1,63.1,52.5,40.3,39.7,34.6,30.9,23.6,20.2,13.7; HRMS(ESI)C 36 H 43 Br2N3O3[M+H]calcd=725.5660; found=646.2485.

[0114] Example 15 Compound 7

[0115] Compound 7 was synthesized using the method described in Example 4. The physicochemical properties of compound 7 are as follows:

[0116] 1) Yellow liquid;

[0117] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0118] Using CDCl3 as the solvent, the peaks were assigned as follows: 1 H NMR(600MHz CDC13)δ:8.37(s,1H,-NH-),8.19(d,J=7.8Hz,1H,-Ph),7.74-7.71(m,2H,-Ph),7.66(dd,J=7.8Hz,0.6Hz,1H,-Ph),7.52(s,1H,-Ph),7.41-7.3 9(m,1H,-Ph),7.34(d,J=1.0Hz,1H,-Ph),7.00(d,J=9.0Hz,1H,-Ph),6.11-6.02(m,2H,-CH=),5.20-5.12(m,4H,=CH2),4.71(s,2H,-CH2-),4.23 -4.21(m,2H,-CH2-),3.94-3.917(m,2H,-CH2-),3.57(d,J=6.6Hz,2H,-CH2-),3.50(d,J=6.6Hz,2H,-CH2-),3.471(s,6H,-CH3),3.298(d,J=7. 2Hz,2H,-CH2-),2.46(dd,J=10.2Hz,5.4Hz,2H,-CH2-),1.58(t,J=7.2Hz,2H,-CH2-),1.39(d,J=7.2Hz,2H,-CH2-),0.92(t,J=7.2Hz,3H,-CH3); 13 C NMR(150MHz CDCl3)δ:162.4,161.7,155.6,146.8,142.9,137.3,136.8,134.3,130.5,129.1,128.7,127.3,126.1,124.8 ,124.2,123.0,118.4,116.2,111.6,64.2,63.1,52.5,40.3,39.7,34.3,30.9,23.6,20.2,13.7; HRMS(ESI)C 36 H 43 Br2N3O3[M+H]calcd=725.5660; found=646.2485.

[0119] Example 16 Compound 8

[0120] Compound 8 was synthesized using the method described in Example 4. The physicochemical properties of compound 8 are as follows:

[0121] 1) Yellow liquid;

[0122] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13C NMR (600MHz) characteristics:

[0123] Using CDCl3 as the solvent, the peaks were assigned as follows: 1 H NMR(600MHz CDCl3)δ:8.91(s,1H,-NH-),8.10(d,J=8.4Hz,2H,-Ph),7.74(d,J=9.6Hz,2H,-Ph),7.67(d,J=8.4Hz,2H,-Ph),7.51(s,1H,-Ph), 7.33(s,1H,-Ph),6.99(d,J=8.4Hz,1H,-Ph),6.09-6.03(m,2H,-CH=),5.17-5.11(m,4H,=CH2),4.68(s,2H,-CH2-),4.21(t,J=4.8 Hz,2H,-CH2-),3.94-3.92(m,2H,-CH2-),3.56(d,J=6.6Hz,2H,-CH2-),3.49(d,J=6.0Hz,2H,-CH2-),3.47(s,6H,-CH3),3.29(q, J=6.6Hz,2H,-CH2-),2.45(d,J=4.2Hz,2H,-CH2-),1.58(d,J=7.8Hz,2H,-CH2-),1.37(d,J=7.8Hz,2H,-CH2-),0.92(s,3H,-CH3); 13 C NMR(150MHz CDCl3)δ:162.5,155.6,146.8,143.0,137.4,136.9,132.2,130.2,129.0,127.4,126.2,126.1,124.7,12 4.1,118.3,116.2,116.0,111.5,64.2,63.1,52.5,40.3,39.7,34.4,30.9,23.6,20.2,13.7; HRMS(ESI)C 36 H 43 Br2N3O3[M+H]calcd=725.5660; found=646.2486.

[0124] Example 17 Compound 9

[0125] Compound 9 was synthesized using the method described in Example 4. The physicochemical properties of compound 9 are as follows:

[0126] 1) Yellow liquid;

[0127] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (400MHz) characteristics:

[0128] Using CDCl3 as the solvent, the peaks were assigned as follows: 1 H NMR(400MHz CDCl3)δ:9.11(s,1H,-NH-),8.17(t,J=12Hz,1H,-Ph),7.75(d,J=6.4Hz,2H,-Ph),7.55(s,1H,-Ph),7.36(d,J=1.2Hz,1H,-Ph ),7.31(s,1H,-Ph),7.28(s,1H,-Ph),6.97(d,J=9.2Hz,1H,-Ph),6.10-5.99(m,2H,-CH=),5.13-5.08(m,4H,=CH2),4.66(s,2 H,-CH2-),4.19(s,2H,-CH2-),3.92(s,2H,-CH2-),3.57(d,J=6.4Hz,2H,-CH2-),3.46(s,8H,-CH2-,-CH3),3.28(d,J=5.2Hz, 2H,-CH2-),2.44(s,2H,-CH2-),1.57(t,J=7.2Hz,2H,-CH2-),1.40-1.36(m,2H,-CH2-),0.93-0.89(m,3H,-CH3); HRMS(ESI)C 36 H 42 BrClFN3O3[M+H]calcd=699.1024; found=618.2919.

[0129] Example 18 Compound 10

[0130] Compound 10 was synthesized using the method described in Example 4. The physicochemical properties of compound 10 are as follows:

[0131] 1) Yellow liquid;

[0132] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0133] Using CDCl3 as the solvent, the peaks were assigned as follows: 1H NMR(600MHz CDCl3)δ:8.91(s,1H,-NH-),8.36-8.35(m,1H,-Ph),7.77-7.73(m,2H,-Ph),7.62-7.59(m,2H,-Ph),7.57(s,1H,-Ph),7.38(d,J=1.2Hz ,1H,-Ph),7.16(dd,J=10.2Hz,9Hz,1H,-Ph),6.98(d,J=8.4Hz,1H,-Ph),6.09-6.03(m,2H,-CH=),5.17-5.11(m,4H,=CH2),4.71(s,2H,- CH2-),4.21(t,J=5.4Hz,2H,-CH2-),3.94-3.909(m,2H,-CH2-),3.57(d,J=6.6Hz,2H,-CH2-),3.49(s,2H,-CH2-),3.47(s,6H,-CH3),3 .29(d,J=6.0Hz,2H,-CH2-),2.45(d,J=4.2Hz,2H,-CH2-),1.60-1.57(m,2H,-CH2-),1.40-1.37(m,2H,-CH2-),0.93-0.92(m,3H,-CH3); 13 C NMR(150MHzCDCl3)δ:162.5,160.6,158.9,158.3,155.7,146.6,142.5,137.7,137.3,135.8,135.7,132.8,130.2,128.7, 128.5,127.3,125.0,124.2,118.6,116.3,111.5,64.2,63.1,52.5,40.3,39.7,34.4,30.9,23.6,20.2,13.7; HRMS(ESI)C 36 H 42 Br2FN3O3[M+H]calcd=743.5564; found=664.2390.

[0134] Example 19 Compound 11

[0135] Compound 11 was synthesized using the method described in Example 4. The physicochemical properties of compound 11 are as follows:

[0136] 1) Yellow liquid;

[0137] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0138] Using CDCl3 as solvent, the peak assignments are as follows: 1 H NMR(600MHz CDCl3)δ:8.83(t,J=5.4Hz,1H,-NH-),8.06-8.00(m,2H,-Ph),7.73-7.71(m,2H,-Ph),7.51(s,1H,-Ph),7.33-7.26(m,2H,-Ph), 6.99(d,J=9Hz,1H,-Ph),6.09-6.02(m,2H,-CH=),5.17-5.12(m,4H,=CH2),4.72(s,2H,-CH2-),4.22(t,J=5.4Hz,2H,-CH2-),3. 95-3.92(m,2H,-CH2-),3.56(d,J=6.6Hz,2H,-CH2-),3.50(d,J=6Hz,2H,-CH2-),3.47(s,6H,-CH3),3.30-3.29(m,2H,-CH2-),2 .46(dd,J=10.8Hz,6Hz,2H,-CH2-),1.59-1.57(m,2H,-CH2-),1.40-1.37(m,2H,-CH2-),0.93(d,J=7.2Hz,3H,-CH3); HRMS(ESI)C 36 H 42 BrF2N3O3[M+H]calcd=682.6508; found=602.3194.

[0139] Example 20 Compound 12

[0140] Compound 12 was synthesized using the method described in Example 4. The physicochemical properties of compound 12 are as follows:

[0141] 1) Yellow liquid;

[0142] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0143] Using CDCl3 as solvent, the peak assignments are as follows: 1H NMR(600MHz CDCl3)δ:8.89-8.852(m,1H,-NH-),8.00-7.96(m,2H,-Ph),7.74-7.70(m,2H,-Ph),7.56-7.51(m,2H,-Ph),7.36-7.34(m,1 H,-Ph),7.01-6.98(m,1H,-Ph),6.10-6.01(m,2H,-CH=),5.17-5.12(m,4H,=CH2),4.72(s,2H,-CH2-),4.22(t,J=5.4Hz,2H, -CH2-),3.95-3.93(m,2H,-CH2-),3.56(d,J=6.6Hz,2H,-CH2-),3.50(s,2H,-CH2-),3.48(s,6H,-CH3),3.31-3.27(m,2H,-C H2-),2.48-2.44(m,2H,-CH2-),1.58(t,J=7.2Hz,2H,-CH2-),1.38(dd,J=15Hz,7.8Hz,2H,-CH2-),0.93-0.91(m,3H,-CH3); 13 C NMR(150MHz CDCl3)δ:162.5,161.2,155.7,146.8,142.9,137.7,137.3,136.8,131.3,130.1,128.7,127.3,125.0,124.2,11 8.4,116.3,116.1,115.6,115.4,111.6,64.2,63.1,52.5,40.2,39.7,34.3,31.0,23.6,20.2,13.7; HRMS(ESI)C 36 H 42 BrClFN3O3[M+H]calcd=699.1024; found=618.2917.

[0144] Example 21 Compound 13

[0145] Compound 13 was synthesized using the method described in Example 4. The physicochemical properties of compound 13 are as follows:

[0146] 1) Yellow liquid;

[0147] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0148] Using CDCl3 as solvent, the peak assignments are as follows: 1H NMR(600MHz CDCl3)δ:8.86(s,1H,-NH-),8.22(dd,J=9.0Hz,6.0Hz,1H,-Ph),7.77-7.75(m,2H,-Ph),7.57(s,1H,-Ph),7.37(d,J=1.0Hz,1H,-Ph), 7.32-7.30(m,1H,-Ph),7.16-7.13(m,1H,-Ph),6.96(d,J=8.4Hz,1H,-Ph),6.08-6.00(m,2H,-CH=),5.17-5.06(m,4H,=CH2),4.72(s,2 H,-CH2-),4.20-4.18(m,2H,-CH2-),3.92(t,J=7.8Hz,2H,-CH2-),3.574(d,J=6.6Hz,2H,-CH2-),3.47(s,8H,-CH2-,-CH3),3.29(q,J =6.6Hz,2H,-CH2-),2.44(d,J=4.2Hz,2H,-CH2-),1.58(t,J=7.2Hz,2H,-CH2-),1.39-1.36(m,2H,-CH2-),0.91(t,J=1.2Hz,3H,-CH3); 13 C NMR(150MHzCDCl3)δ:164.6,162.9,162.5,160.6,155.7,146.7,142.5,137.5,136.9,134.7,133.5,130.2,128.6,127.4,124.1,122 .7,118.9,118.8,118.5,116.2,115.8,114.8,114.7,111.5,64.2,63.1,52.5,40.3,39.6,34.6,31.0,23.6,20.2,13.7; HRMS(ESI)C 36 H 42 BrClFN3O3[M+H]calcd=699.1024; found=618.2921.

[0149] Example 22 Compound 14

[0150] Compound 14 was synthesized using the method described in Example 4. The physicochemical properties of compound 14 are as follows:

[0151] 1) Yellow liquid;

[0152] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0153] Using CDCl3 as solvent, the peak assignments are as follows: 1 H NMR(600MHz CDCl3)δ:8.84(s,1H,-NH-),8.31(d,J=7.2Hz,1H,-Ph),8.16-8.14(m,1H,-Ph),7.74(d,J=10.2Hz,2H,-Ph),7.52(s,1H,-Ph), 7.35-7.30(m,2H,-Ph),7.02(d,J=8.4Hz,1H,-Ph),6.13-6.03(m,2H,-CH=),5.20-5.14(m,4H,=CH2),4.70(s,2H,-CH2-),4.24 -4.23(m,2H,-CH2-),3.97-3.95(m,2H,-CH2-),3.58(d,J=6.6Hz,2H,-CH2-),3.52(s,2H,-CH2-),3.50(s,6H,-CH3),3.31-3.2 8(m,2H,-CH2-),2.48(d,J=3.6Hz,2H,-CH2-),1.60-1.58(m,2H,-CH2-),1.41-1.38(m,2H,-CH2-),0.93(t,J=7.2Hz,3H,-CH3); 13 C NMR(150MHz CDCl3)δ:162.5,161.1,159.2,155.6,146.8,142.9,137.6,137.3,136.8,130.1,128.7,127.3 ,124.8,118.3,116.2,111.6,64.3,63.1,52.6,40.2,34.3,31.1,23.6,20.2,13.7; HRMS(ESI)C 36 H 42 BrClFN3O3[M+H]calcd=699.1024; found=618.2904.

[0154] Example 23 Compound 15

[0155] Compound 15 was synthesized using the method described in Example 4. The physicochemical properties of compound 15 are as follows:

[0156] 1) Yellow liquid;

[0157] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (400MHz) characteristics:

[0158] Using CDCl3 as solvent, the peak assignments are as follows: 1H NMR(400MHz CDCl3)δ:9.28(s,1H,-NH-),8.08-8.06(m,1H,-Ph),7.78-7.75(m,2H,-Ph),7.65(dd,J=12.0Hz,7.8Hz,1H,-Ph),7.59(d,J=0.8Hz,1H ,-Ph),7.39-7.26(m,2H,-Ph),6.96(d,J=9.2Hz,1H,-Ph),6.09-6.00(m,2H,-CH=),5.18-5.06(m,4H,=CH2),4.69(s,2H,-CH2-),4.19( s,2H,-CH2-),3.89(s,2H,-CH2-),3.58(d,J=6.4Hz,2H,-CH2-),3.48(d,J=4.8Hz,2H,-CH2-),3.45(s,6H,-CH3),3.28(d,J=5.2Hz,2H, -CH2-),2.43(s,2H,-CH2-),1.59-1.56(t,J=6.4Hz,2H,-CH2-),1.38(t,J=7.6Hz,2H,-CH2-),0.93(d,J=7.2Hz,3H,-CH3); HRMS(ESI)C 36 H 42 BrCl2N3O3[M+H]calcd=715.5540; found=634.2602.

[0159] Example 24 Compound 16

[0160] Compound 16 was synthesized using the method described in Example 4. The physicochemical properties of compound 16 are as follows:

[0161] 1) Yellow liquid;

[0162] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0163] Using CDCl3 as solvent, the peak assignments are as follows: 1H NMR(600MHz CDCl3)δ:8.86(s,1H,-NH-),8.17(d,J=8.4Hz,1H,-Ph),7.77-7.74(m,2H,-Ph),7.59-7.57(m,2H,-Ph),7.41-7.38(m,2H,- Ph),6.96(d,J=8.4Hz,1H,-Ph),6.08-6.00(m,2H,-CH=),5.17-5.0647(m,4H,=CH2),4.689(s,2H,-CH2-),4.20-4.18(m,2H, -CH2-),3.92(t,J=8.4Hz,2H,-CH2-),3.57(d,J=6.6Hz,2H,-CH2-),3.46(s,8H,-CH2-,-CH3),3.29(d,J=6.6Hz,2H,-CH2-) ,2.45-2.42(m,2H,-CH2-),1.57(t,J=7.2Hz,2H,-CH2-),1.38(dd,J=9.0Hz,7.8Hz,2H,-CH2-),0.92(d,J=7.2Hz,3H,-CH3); 13 C NMR(150MHz CDCl3)δ:162.5,160.5,155.7,146.7,142.5,137.6,137.3,136.9,132.6,131.3,130.2,127.5,124.9,1 24.2,118.6,116.2,115.8,115,64.2,63.1,52.5,40.3,39.6,34.6,30.9,23.6,20.2,13.7; HRMS(ESI)C 36 H 42 BrCl2N3O3[M+H]calcd=715.5540; found=634.2617.

[0164] Example 25 Compound 17

[0165] Compound 17 was synthesized using the method described in Example 4. The physicochemical properties of compound 17 are as follows:

[0166] 1) Yellow liquid;

[0167] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0168] Using CDCl3 as solvent, the peak assignments are as follows: 1H NMR(600MHz CDCl3)δ:8.86(s,1H,-NH-),7.74(dd,J=8.4Hz,2.4Hz,1H,-Ph),7.65-7.62(m,2H,-Ph),7.47-7.46(m,2H,-Ph),7.43-7.39(m ,2H,-Ph),6.93(d,J=9.6Hz,1H,-Ph),6.10-5.97(m,2H,-CH=),5.20-5.04(m,4H,=CH2),4.68(s,2H,-CH2-),4.16(t,J=5.4Hz, 2H,-CH2-),3.90-3.87(m,2H,-CH2-),3.59(d,J=6.6Hz,2H,-CH2-),3.44(s,8H,-CH2-,-CH3),3.28(dd,J=12.6Hz,7.2Hz,2H, -CH2-),2.43-2.39(m,2H,-CH2-),1.58-1.55(m,2H,-CH2-),1.37(dd,J=15Hz,7.8Hz,2H,-CH2-),0.90(t,J=7.2Hz,3H,-CH3); 13 C NMR(150MHz CDCl3)δ:162.4,158.4,155.7,146.9,142.1,137.3,136.8,136.3,132.2,130.2,127.6,125.1,124.6 ,118.9,116.3,115.8,111.4,64.1,63.0,52.5,40.3,39.6,34.5,30.9,23.5,20.2,13.7; HRMS(ESI)C 36 H 42 BrCl2N3O3[M+H]calcd=715.5540; found=634.2622.

[0169] Example 24 Compound 18

[0170] Compound 18 was synthesized using the method described in Example 4. The physicochemical properties of compound 18 are as follows:

[0171] 1) A light yellow liquid;

[0172] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0173] Using CDCl3 as solvent, the peak assignments are as follows: 1H NMR(600MHz CDCl3)δ:8.82(s,1H,-NH-),8.30(s,1H,-Ph),8.07-8.05(m,1H,-Ph),7.71(d,J=10.8Hz,2H,-Ph),7.59(dd,J=8.4Hz,3Hz ,1H,-Ph),7.51(s,1H,-Ph),7.34(s,1H,-Ph),7.00(dd,J=8.4Hz,3Hz,1H,-Ph),6.10-6.02(m,2H,-CH=),5.19-5.13(m,4H ,=CH2),4.71(s,2H,-CH2-),4.22(s,2H,-CH2-),3.94(d,J=4.2Hz,2H,-CH2-),3.55(s,2H,-CH2-),3.49(s,8H,-CH2-,-CH 3),3.28(s,2H,-CH2-),2.46(s,2H,-CH2-),1.58(d,J=6Hz,2H,-CH2-),1.39-1.37(m,2H,-CH2-),0.93-0.91(m,3H,-CH3); 13 C NMR(150MHz CDCl3)δ:162.5,161.0,155.7,146.8,142.8,137.7,137.3,136.8,135.8,133.5,131.1,130.1,129.2,128.7,127.3,12 6.5,125.0,124.3,118.4,116.3,116.2,111.6,64.3,63.1,52.6,40.2,39.7,34.3,31.0,23.6,20.2,13.7; HRMS(ESI)C 36 H 42 BrCl2N3O3[M+H]calcd=715.5540; found=634.3272.

[0174] Example 25 Compound 19

[0175] Compound 19 was synthesized using the method described in Example 4. The physicochemical properties of compound 19 are as follows:

[0176] 1) Yellow liquid;

[0177] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0178] Using CDCl3 as solvent, the peak assignments are as follows: 1H NMR(600MHz CDCl3)δ:8.88(s,1H,-NH-),8.10(d,J=1.8Hz,2H,-Ph),7.73-7.68(m,2H,-Ph),7.52-7.50(m,2H,-Ph),7.35(d,J=1.2Hz,1H,-P h),7.00(d,J=8.4Hz,1H,-Ph),6.11-6.01(m,2H,-CH=),5.22-5.13(m,4H,=CH2),4.71(s,2H,-CH2-),4.22(t,J=3.6Hz,2H,-CH2 -),3.95-3.92(m,2H,-CH2-),3.56(d,J=6.6Hz,2H,-CH2-),3.50(s,2H,-CH2-),3.48(s,6H,-CH3),3.31-3.27(m,2H,-CH2-),2. 47(dd,J=10.2Hz,5.4Hz,2H,-CH2-),1.60-1.57(m,2H,-CH2-),1.40-1.36(t,J=22.5Hz,2H,-CH2-),0.92(t,J=7.2Hz,3H,-CH3); 13 C NMR(150MHz CDCl3)δ:162.5,160.6,155.7,146.9,142.7,137.8,137.2,136.7,135.8,131.2,130.1,128.5,127.2,125.7 ,125.2,124.3,118.5,116.3,111.6,64.2,63.1,52.5,40.2,39.7,34.2,30.9,23.6,20.2,13.7; HRMS(ESI)C 36 H 42 BrCl2N3O3[M+H]calcd=715.5540; found=634.2622.

[0179] Example 26 Compound 20

[0180] Compound 20 was synthesized using the method described in Example 4. The physicochemical properties of compound 20 are as follows:

[0181] 1) Yellow liquid;

[0182] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0183] Using CDCl3 as solvent, the peak assignments are as follows: 1H NMR(600MHz CDCl3)δ:8.89(s,1H,-NH-),8.12(d,J=12.6Hz,1H,-Ph),7.79-7.78(m,2H,-Ph),7.58(s,1H,-Ph),7.46-7.43(m,1H,-Ph),7.38( s,1H,-Ph),7.15-7.10(m,1H,-Ph),6.96(d,J=10.8Hz,1H,-Ph),6.10-5.98(m,2H,-CH=),5.18-5.08(m,4H,=CH2),4.56(d,J=53. 4Hz,2H,-CH2-),4.17(s,2H,-CH2-),3.91(s,2H,-CH2-),3.58(d,J=9.6Hz,2H,-CH2-),3.46(d,J=9.0Hz,2H,-CH2-),3.43(s,6H, HRMS(ESI)C 36 H 42 Br2ClN3O3[M+H]calcd=760.0080; found=680.2083.

[0184] Example 27 Compound 21

[0185] Compound 21 was synthesized using the method described in Example 4. The physicochemical properties of compound 21 are as follows:

[0186] 1) Yellow liquid;

[0187] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0188] Using CDCl3 as the solvent, the peaks were assigned as follows: 1H NMR(600MHz CDCl3)δ:8.83(s,1H,-NH-),8.37-8.36(m,1H,-Ph),8.11-8.09(m,1H,-Ph),7.65-7.63(m,2H,-Ph),7.44(d,J=1.2Hz,1H,- Ph),7.19(s,2H,-Ph),6.93(d,J=8.4Hz,1H,-Ph),6.03-5.94(m,2H,-CH=),5.12-5.05(m,4H,=CH2),4.62(s,2H,-CH2-),4.1 5(s,2H,-CH2-),3.86(s,2H,-CH2-),3.49(d,J=6.6Hz,2H,-CH2-),3.44(d,J=6.0Hz,2H,-CH2-),3.44(s,6H,-CH3),3.22-3. 20(m,2H,-CH2-),2.39(s,2H,-CH2-),1.52-1.50(m,2H,-CH2-),1.314(d,J=7.8Hz,2H,-CH2-),0.84(t,J=7.2Hz,3H,-CH3); 13 C NMR(150MHz CDCl3)δ:162.5,161.9,161.0,160.2,155.6,146.9,137.6,137.3,136.8,132.8,130.2,127.3,124.2 ,118.4,116.2,111.6,110.0,64.3,63.1,52.6,40.2,39.7,34.3,31.0,23.6,20.2,13.7; HRMS(ESI)C 36 H 42 B r2 FN3O3[M+H]calcd=743.5564; found=664.2390.

[0189] Example 28 Compound 22

[0190] Compound 22 was synthesized using the method described in Example 4. The physicochemical properties of compound 22 are as follows:

[0191] 1) Yellow liquid;

[0192] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (400MHz) characteristics:

[0193] Using CDCl3 as the solvent, the peaks were assigned as follows: 1H NMR(400MHz CDC13)δ:8.89(s,1H,-NH-),8.47(s,1H,-Ph),8.12(d,J=8.4Hz,1H,-Ph),7.72(d,J=8.8Hz,2H,-Ph),7.61(d,J =8.4Hz,1H,-Ph),7.51(s,1H,-Ph),7.34(s,1H,-Ph),7.00(d,J=8.0Hz,1H,-Ph),6.08-6.04(m,2H,-CH=),5.20 -5.12(m,4H,=CH2),4.72(s,2H,-CH2-),4.22(s,2H,-CH2-),3.93(t,J=7.6H z,2H,-CH2-),3.57(d,J=6.4Hz,2H,-CH2-),3.49(s,2H,-CH2-),3.46(s,6H,- CH3),3.28(t,J=6.4Hz,2H,-CH2-),2.43(s,2H,-CH2-),1.60-1.56(m,2H,-C H2-),1.371(d,J=7.6Hz,2H,-CH2-),0.93(d,J=6.4Hz,3H,-CH3); HRMS(ESI)C 36 H 42 Br2ClN3O3[M+H]calcd=760.0080; found=680.2094.

[0194] Example 29 Compound 23

[0195] Compound 23 was synthesized using the method described in Example 4. The physicochemical properties of compound 23 are as follows:

[0196] 1) A light yellow liquid;

[0197] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0198] Using CDCl3 as solvent, the peak assignments are as follows: 1H NMR(600MHz CDCl3)δ:8.80(s,1H,-NH-),8.04(d,J=8.4Hz,1H,-Ph),7.94(s,1H,-Ph),7.77(d,J=9.6Hz,2H,-Ph),7.60-7.57(m, 2H,-Ph),7.38(s,1H,-Ph),6.96(d,J=7.8Hz,1H,-Ph),6.08-6.00(m,2H,-CH=),5.17-5.06(m,4H,=CH2),4.69(s,2H ,-CH2-),4.20(s,2H,-CH2-),3.92(s,2H,-CH2-),3.58(d,J=6.6Hz,2H,-CH2-),3.47(s,8H,-CH2-,-CH3),3.28(s,2 H,-CH2-),2.44(s,2H,-CH2-),1.59-1.56(m,2H,-CH2-),1.38(q,J=7.8Hz,2H,-CH2-),0.913(t,J=7.2Hz,3H,-CH3); 13 C NMR(150MHzCDCl3)δ:162.5,161.1,155.7,146.8,142.4,137.3,133.1,130.9,130.3,128.6,125.7,125.0,124 .3,122.2,118.6,116.3,115.8,111.5,64.2,63.2,52.7,40.3,39.7,34.6,31.0,23.6,20.2,13.7; HRMS(ESI)C 36 H 42 Br3N3O3[M+H]calcd=804.4620; found=724.1581.

[0199] Example 30 Compound 24

[0200] Compound 24 was synthesized using the method described in Example 4. The physicochemical properties of compound 24 are as follows:

[0201] 1) Yellow liquid;

[0202] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0203] Using CDCl3 as solvent, the peak assignments are as follows: 1H NMR(600MHz CDCl3)δ:8.87(s,1H,-NH-),8.30(d,J=7.2Hz,2H,-Ph),7.80(d,J=1.8Hz,1H,-Ph),7.72(s,1H,-Ph),7.68(d,J=8.4Hz,1H,-Ph),7.51(s, 1H,-Ph),7.34(s,1H,-Ph),6.99(d,J=8.4Hz,1H,-Ph),6.11-6.01(m,2H,-CH=),5.22-5.13(m,4H,=CH2),4.71(s,2H,-CH2-),4.23-4.21(m ,2H,-CH2-),3.95-3.92(m,2H,-CH2-),3.56(d,J=6.6Hz,2H,-CH2-),3.50(s,2H,-CH2-),3.48(s,6H,-CH3),3.30-3.27(m,2H,-CH2-),2.4 7(dd,J=10.2Hz,5.4Hz,2H,-CH2-),1.59-1.57(m,2H,-CH2-),1.39(dd,J=14.4Hz,7.2Hz,2H,-CH2-),0.93-0.90(m,3H,-CH3); HRMS(ESI)C 36 H 42 Br3N3O3[M+H]calcd=804.4620; found=724.1581.

[0204] Example 31 Compound 25

[0205] Compound 25 was synthesized using the method described in Example 4. The physicochemical properties of compound 25 are as follows:

[0206] 1) Yellow liquid;

[0207] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0208] Using CDCl3 as the solvent, the peaks were assigned as follows: 1H NMR(600MHz CDC13)δ:9.06(s,1H,-NH-),7.87-7.84(m,2H,-Ph),7.70-7.67(m,2H,-Ph),7.50(d,J=1.8Hz,1H,-Ph),7.35(d,J= 1.8Hz,1H,-Ph),7.00(d,J=12.0Hz,1H,-Ph),6.12-5.99(m,2H,-CH=),5.18-5.12(m,4H,=CH2),4.71(s,2H,-CH2-), 4.22(s,2H,-CH2-),3.93(s,2H,-CH2-),3.56(d,J=9.6Hz,2H,-CH2-),3.48(s,8H,-CH2-,-CH3),3.28(s,2H,-CH2-) ,2.47(s,2H,-CH2-),1.60-1.54(m,2H,-CH2-),1.41-1.35(m,2H,-CH2-),0.91(t,J=10.8Hz,3H,-CH3); HRMS(ESI)C 36 H 41 BrF3N3O3[M+H]calcd=700.6412; found=620.3192.

[0209] Example 32 Compound 26

[0210] Compound 26 was synthesized using the method described in Example 4. The physicochemical properties of compound 26 are as follows:

[0211] 1) Yellow liquid;

[0212] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (400MHz) characteristics:

[0213] Using CDCl3 as the solvent, the peaks were assigned as follows: 1H NMR(400MHz CDCl3)δ:9.00(s,1H,-NH-),7.84-7.73(m,4H,-Ph),7.52(s,1H,-Ph),7.44-7.40(m,1H,-Ph),7.32(d,J=1.2Hz,1H,-Ph),7.08(dd, J=8.0Hz,2.4Hz,1H,-Ph),7.98(d,J=9.2Hz,1H,-Ph),6.11-6.00(m,2H,-CH=),5.18-5.10(m,4H,=CH2),4.59(s,2H,-CH2-),4.18(s ,2H,-CH2-),3.91(s,5H,-CH2-,-OCH3),3.56(d,J=6.4Hz,2H,-CH2-),3.49(d,J=6.4Hz,2H,-CH2-),3.45(s,6H,-CH3),3.28-3.24( m,2H,-CH2-),2.43(s,2H,-CH2-),1.55(t,J=7.2Hz,2H,-CH2-),1.39-1.35(m,2H,-CH2-),0.90(t,J=7.2Hz,3H,-CH3); HRMS(ESI)C 37 H 46 BrN3O4[M+H]calcd=676.6960; found=596.3489.

[0214] Example 33 Compound 27

[0215] Compound 27 was synthesized using the method described in Example 4. The physicochemical properties of compound 27 are as follows:

[0216] 1) Yellow liquid;

[0217] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0218] Using CDCl3 as solvent, the peak assignments are as follows: 1H NMR(600MHz CDC13)δ:8.88(s,1H,-NH-),8.19(d,J=9.0Hz,2H,-Ph),7.76-7.73(m,2H,-Ph),7.48(d,J=1.2Hz,1H,-Ph),7.28(d,J=1.2Hz,1H,-Ph),7.033(d, J=9.0Hz,2H,-Ph),6.98(d,J=8.4Hz,1H,-Ph),6.10-6.02(m,2H,-CH=),5.16-5.11(m,4H,=CH2),4.71(s,2H,-CH2-),4.21(t,J=5.4Hz,2H,-CH2-) ,3.93(t,J=8.4Hz,2H,-CH2-),3.89(s,3H,-OCH3),3.55(d,J=6.6Hz,2H,-CH2-),3.49(d,J=6.6Hz,2H,-CH2-),3.47(s,6H,-CH3),3.29(dd,J=13. 2Hz,7.2Hz,2H,-CH2-),2.46-2.43(m,2H,-CH2-),1.58(t,J=7.2Hz,2H,-CH2-),1.38(dd,J=15Hz,7.2Hz,2H,-CH2-),0.92(t,J=7.2Hz,3H,-CH3); 13 C NMR(150MHz CDCl3)δ:163.4,162.5,162.3,155.5,146.7,143.3,137.5,137.0,136.9,130.2,129.4,129.0,128.6,127.4,123. 8,119.7,116.0,115.9,114.4,111.5,64.2,63.1,55.5,52.5,40.3,39.7,34.4,30.9,23.6,20.7,13.7; HRMS(ESI)C 37 H 46 BrN3O4[M+H]calcd=676.6960; found=596.3493.

[0219] Example 34 Compound 28

[0220] Compound 28 was synthesized using the method described in Example 4. The physicochemical properties of compound 28 are as follows:

[0221] 1) Yellow liquid;

[0222] 2) The nuclear magnetic resonance spectrum of this compound ( 1 H / 13 C NMR (600MHz) characteristics:

[0223] Using CDCl3 as solvent, the peak assignments are as follows: 1 H NMR(600MHz CDCl3)δ:8.87(s,1H,-NH-),8.36(d,J=8.4Hz,2H,-Ph),7.79(d,J=8.4Hz,2H,-Ph),7.75-7.73(m,2H,-Ph),7.55(t,J=0.6Hz,1H,-Ph),7 .36(d,J=1.8Hz,1H,-Ph),7.00(d,J=8.4Hz,1H,-Ph),6.09-6.02(m,2H,-CH=),5.18-5.11(m,4H,=CH2),4.71(s,2H,-CH2-),4.23-4.21( m,2H,-CH2-),3.94(t,J=7.8Hz,2H,-CH2-),3.58(d,J=6.6Hz,2H,-CH2-),3.50(d,J=6.0Hz,2H,-CH2-),3.48(s,6H,-CH3),3.31-3.27(m ,2H,-CH2-),2.47(d,J=5.4Hz,2H,-CH2-),1.58(d,J=7.2Hz,2H,-CH2-),1.39-1.36(m,2H,-CH2-),0.93-0.90(m,3H,-CH3); HRMS(ESI)C 37 H 43 BrF3N3O3[M+H]calcd=714.6682; found=634.3273.

[0224] Application Example 1: In vitro antibacterial activity assay

[0225] 1. Test bacteria:

[0226] Staphylococcus aureus (ATCC 29213); Escherichia coli (ATCC 25922); Methicillin-resistant Staphylococcus aureus (MRSA).

[0227] 2. Samples and reagents:

[0228] The samples were: honokiol, vancomycin, meropenem, and compounds 1-28 prepared in the examples.

[0229] 3. Testing Method:

[0230] According to the Clinical Laboratory Standards Institute (CLSI) standards, the in vitro antibacterial activity of magnolol, compounds 1-28 of this invention, and the clinical antibacterial drug vancomycin was tested using a 96-well plate with serial dilutions. The minimum drug concentration observed with the naked eye in the smallest completely clear well was defined as the MIC value.

[0231] Table 1. MIC values ​​of the oxazole ring-containing and magnolol-antimicrobial peptide mimic conjugates 1-28 of the present invention against 10 clinical MRSA isolates.

[0232]

[0233]

[0234] Sa a .:S.aureusATCC 29213;M11-23 b :10 clinical MRSA strains; Ec c .:E.coli ATCC 25922;SI d Selectivity coefficient (HC) 50 / MICs of S.aureus); ND e Undetected. Van f Vancomycin; MEM g Meropenem. The experiment should be repeated at least 3 times.

[0235] Table 1 shows that most of the oxazole ring-containing and magnolol-antimicrobial peptide mimic conjugates prepared in this invention exhibit enhanced antibacterial activity against Gram-positive bacteria compared to the substrate and magnolol. Only a few compounds showed a decreasing trend in antibacterial efficacy, but none of the prepared conjugates showed significant antibacterial activity against E. coli. Considering the overall antibacterial results, compound 17 showed the most significant antibacterial effect against Gram-positive bacteria among the 28 conjugates, with MIC values ​​between 2 and 8 μg / mL. Compound 17 (HC 50 =281.1, SI=54.52) compared to the lead compound and magnolol (HC 50 With SI=80 and SI=5, the significant improvement in hemolytic activity and membrane selectivity indicates that the compound has high safety.

[0236] Application Example 2: Time-based bactericidal kinetics experiment of compound 17:

[0237] 1. Test bacteria:

[0238] S. aureus ATCC 29213; MRSA-20 (clinical isolate).

[0239] 2. Samples and reagents:

[0240] The samples were: vancomycin and compound 17 prepared in the example.

[0241] 3. Testing Method:

[0242] Single colonies of S. aureus ATCC 29213 and MRSA-20 were inoculated into 1 mL of LB broth and cultured overnight. 50 μL of the bacterial culture was then transferred to 50 mL of LB broth for further culture for 2.5 h (37℃, 200 rpm). The bacterial concentration was determined to be 1 × 10⁻⁶ after the culture was completed. 7 CFU / mL. Four experimental groups were set up: 4×MIC / 8×MIC compound group, 8×MIC vancomycin group, and control group. Compound 17 solution dissolved in DMSO and vancomycin solution were added to the cultured bacterial suspension; the control group received an equal volume of DMSO. The suspensions were then incubated in a shaker. At 0, 0.5, 1, 2, 4, 6, and 8 h, 100 μL of bacterial suspension was collected, washed, resuspended, and serially diluted in 96-well plates. 10 μL of each concentration of the diluted sample was dropped onto MHA solid culture dishes, air-dried, and incubated upside down in a 37℃ incubator for 12–16 h. Colony counts were recorded at different time points, and sterilization curves were plotted. Three parallel controls were set up for each concentration. This experiment was repeated three times. The results are as follows: Figure 1 As shown in A and B.

[0243] Figure 1 A and B indicate that compound 17 (4×MIC and 8×MIC) exhibited higher bactericidal activity against MRSA-20 and *S. aureus* ATCC29213 than vancomycin (8×MIC). For compound 17, the CFU / mL of MRSA-20 decreased by more than 3 logs within 2 hours at 8×MIC and within 8 hours at 4×MIC (killing 99.9% of the bacteria). Simultaneously, compound 17 also showed rapid bactericidal activity against *S. aureus* ATCC29213, completely killing the bacteria within 6 hours at 8×MIC. These results demonstrate that compound 17 possesses rapid bactericidal activity against Gram-positive bacteria MRSA-20 and *S. aureus* ATCC29213, which is beneficial in preventing the spread of bacterial infections.

[0244] Application Example 3: Drug resistance induction experiment of compound 17:

[0245] After determining the initial MIC values ​​of target compound 17 and norfloxacin, single colonies of *S. aureus* ATCC 29213 were placed in two 1 mL LHB liquid culture tubes, and the test compound and norfloxacin (both with a final concentration of 1 / 2 MIC) were added respectively and incubated for 12 h. Using an inoculation loop, the bacterial suspension was inoculated onto MHA solid culture dishes using the three-zone streak method. Once single colonies appeared, the MIC values ​​were re-measured and recorded as the first-generation MIC values. Subsequently, single colonies were picked and inoculated onto MHA solid culture dishes containing sub-inhibitory concentrations of the test compound and norfloxacin, and incubated at 37°C for 12 h. Once single colonies grew, the MIC values ​​were re-measured and recorded as the second-generation MIC values. The above operation was repeated, with the sub-inhibitory concentration adjusted according to the MIC values ​​of each generation. A total of 20 generations were cultured. Results are shown below. Figure 1 C.

[0246] from Figure 1 Results showed that in the presence of compound 17 at a sub-inhibitory concentration (1 / 2 MIC), consecutive passages of *S. aureus* ATCC 29213 over 20 days failed to induce resistance mutants. In contrast, the MIC of norfloxacin increased 128-fold after 16 passages. The rapid bactericidal activity of compound 17 is likely due to its membrane-targeting action, an important characteristic that helps prevent the development of resistance.

[0247] Application Example 4: In vivo safety evaluation experiment

[0248] 1. Reagents:

[0249] Compound 17 prepared in the example, 0.9% NaCl.

[0250] 2. Test animals

[0251] SPF grade KM mice (weight 20-22g, 7-8 weeks old).

[0252] 3. Testing Methods

[0253] Compound 17 was prepared into test compound solutions with physiological saline at concentrations of 5, 10, 20, 40, and 80 mg / kg. Thirty healthy female KM mice of uniform size and weight were randomly divided into 6 groups (n=5 per group) after hair removal from their backs. Mice in the treatment groups were subcutaneously injected with 60 μL of the compound solution at different concentrations in their backs, while mice in the control group were subcutaneously injected with 60 μL of physiological saline in their backs. The survival status of the mice and the presence of skin irritation were observed after injection. 24 hours later, blood was collected from the eyes of mice that did not die or show irritation at the maximum injection concentration for complete blood count, liver function, and kidney function tests to compare for significant changes compared to the control group.

[0254] By subcutaneously injecting mice with different concentrations of the compound, it was found that when the concentration of compound 17 was ≤20mg / kg, no adverse reactions (such as redness, swelling, hardening, ulceration, etc.) were observed in the mice. Therefore, routine blood tests and blood biochemical index tests were performed on the mice at this dosage. Figure 2 The results showed that blood samples underwent routine blood tests and blood biochemistry analysis, including tests for white blood cell count (WBC), red blood cell count (RBC), hemoglobin (HGB), hematocrit (HCT), mean corpuscular volume (MCV), platelet count (PLT), albumin (ALB), urea (UREA), and creatinine (CREA). Statistical results indicated that, compared to the control group (0.9% NaCl), subcutaneous injection of compound 17 (20 mg / kg) into KM mice resulted in no significant differences in any of the results, suggesting that compound 17 has a certain degree of in vivo safety.

[0255] Application Example 5: In vivo anti-MRSA infection activity assay of compound 17

[0256] 1. Test bacteria:

[0257] MRSA-20 (clinical isolate)

[0258] 2. Samples and reagents:

[0259] The samples were: vancomycin and compound 17 prepared in the examples, and 0.9% NaCl.

[0260] 3. Test animals:

[0261] SPF grade KM mice (weight 20-22g, 7-8 weeks old).

[0262] 4. Testing Method:

[0263] Thirty healthy female KM mice of uniform size and weight were shaved from their backs and randomly divided into four groups: a blank control group, a control group (physiological saline), a vancomycin group (5 mg / kg), a high-dose compound group (10 mg / kg), and a low-dose compound group (5 mg / kg), with six mice in each group. After disinfection of the mice's backs, except for the blank control group, all other groups were subcutaneously injected with 60 μL of a bacterial concentration of 1×10⁻⁶. 8 CFU / mL MRSA-20 bacterial suspension. Two hours later, 60 μL of different concentrations of the compound, vancomycin, or physiological saline were injected in situ. Survival and skin infection status of mice in each group were recorded. Twenty-four hours after administration, mice were euthanized by dislocation, and skin from the infected area was harvested. The skin was ground into fragments using a tissue homogenizer, and colony counts were determined using a dropper method. The homogenate was collected from the infected skin tissue, and the results are as follows: Figure 3 As shown.

[0264] The results show that: Figure 3 As shown, the bacterial load in the skin tissue of mice in the Control group was approximately 8.6 log 10 CFU / g, while treatment with low-dose 17 (5 mg / kg) and vancomycin (5 mg / kg) significantly reduced the number of MRSA cells in mouse skin (P<0.0001), and the bacterial load decreased by 3.2 log. 10 cfu / g and 1.9log 10 The cfu / g level showed a moderate therapeutic effect. Furthermore, after 17 days (10 mg / kg) of treatment, the bacterial load on the skin decreased by approximately 4.3 log. 10 The cfu / g concentration showed the most significant therapeutic effect. Therefore, it was confirmed that the oxazole-containing and magnolol-antimicrobial peptide mimic conjugate 17 has a good therapeutic effect on skin abscesses in mice infected with MRSA, and is superior to the control drug vancomycin at the same dose, showing promise as a novel anti-MRSA drug.

Claims

1. A mimicry conjugate containing an oxazole ring and magnolol-antimicrobial peptides, the structure of which is shown in formula (I): in, R1, R2, and R3 can be one of the following combinations: (1) R1=R2=R3=H; (2) R1=R2=H, R3=2-F; (3) R1=R2=H, R3=4-F; (4) R1=R2=H, R3=2-Cl; (5) R1=R2=H, R3=4-Cl; (6) R1=R2=H, R3=2-Br; (7) R1=R2=H, R3=3-Br; (8) R1=R2=H, R3=4-Br; (10) R1=H, R2=2-F, R3=5-Br; (11) R1=H, R2=3-F, R3=4-F; (12) R1=H, R2=3-F, R3=4-Cl; (13) R1=H, R2=2-Cl, R3=4-F; (14) R1=H, R2=3-Cl, R3=4-F; (15) R1=H, R2=2-Cl, R3=3-Cl; (16) R1=H, R2=2-Cl, R3=4-Cl; (17) R1=H, R2=2-Cl, R3=6-Cl; (26) R1=R2=H, R3=3-OCH3; (27) R1=R2=H, R3=4-OCH3.

2. The method for preparing the oxazole ring-containing and magnolol-antimicrobial peptide mimic conjugate according to claim 1, characterized in that, Includes the following steps: (1) Using magnolol as a substrate, react with iodine to convert the ortho-phenolic hydroxyl group and propenyl group into an oxygen-containing five-membered ring to obtain intermediate 2. (2) Intermediate 2 reacts with concentrated nitric acid to introduce a nitro group to synthesize intermediate 3; (3) Intermediate 3 reacts with a reducing agent to reduce the nitro group to an amino group to obtain intermediate 4; (4) Under the action of a catalyst, intermediate 4 undergoes ring-opening of an oxygen-containing five-membered ring to generate phenolic hydroxyl and propenyl groups, thus obtaining intermediate 5; (5) Intermediate 5 reacts with benzaldehyde containing different substituents to generate intermediate 6; (6) Intermediate 6 reacts with a dehydrogenating agent to generate intermediate 7, which contains a nitrogen-containing heterocycle; (7) Intermediate 7 reacts with 1,3-dibromopropane under alkaline conditions to generate intermediate 8; (8) Intermediate 8 then reacts with small molecule peptide mimic 9 to generate the oxazole ring-containing honokiol-antimicrobial peptide mimic conjugate, as shown in the following reaction formula: Wherein, R1, R2 and R3 are as described in claim 1.

3. The method for preparing the oxazole ring-containing honokiol-antimicrobial peptide mimic conjugate according to claim 2, characterized in that, In step (1), the molar ratio of the reaction between magnolol and iodine is 1:(1.0-1.2), the reaction temperature is 45-55℃, and the reaction solvent is ethanol and ultrapure water in a ratio of 9:1-7:3; in step (2), the molar ratio of the reaction between intermediate 2 and concentrated nitric acid is 1:(2.5-3.5), the reaction temperature is 0±5℃, and the reaction solvent is dichloromethane.

4. The method for preparing the oxazole ring-containing honokiol-antimicrobial peptide mimic conjugate according to claim 2, characterized in that, In step (3), the reducing agent is selected from stannous chloride dihydrate; the molar ratio of intermediate 3 to reducing agent is 1:(9-11), the reaction temperature is 75-80℃, and the reaction solvent is ethyl acetate; in step (4), the catalyst is selected from zinc; the molar ratio of intermediate 4 to catalyst is 1:(4-6), the reaction temperature is 75-80℃, and the reaction solvent is anhydrous ethanol.

5. The method for preparing the oxazole ring-containing and magnolol-antimicrobial peptide mimic conjugate according to claim 2, characterized in that, In step (5), the molar ratio of intermediate 5 to benzaldehyde containing different substituents is 1:(2.5-3.5), the reaction temperature is 40-50℃, and the reaction solvent is methanol; in step (6), the dehydrogenating agent is selected from DDQ; the molar ratio of intermediate 6 to dehydrogenating agent is 1:(1.0-1.2), the reaction temperature is room temperature, and the reaction solvent is dichloromethane; in step (7), the molar ratio of intermediate 7 to 1,3-dibromopropane is 1:(2.5-3.5), the reaction temperature is 45-55℃, and the reaction solvent is anhydrous acetone.

6. The method for preparing the oxazole ring-containing honokiol-antimicrobial peptide mimic conjugate according to claim 2, characterized in that, In step (8), the preparation method of the small molecule peptide mimic 9 includes the following steps: bromoacetyl bromide reacts with n-butylamine under alkaline conditions to generate bromoacetamide, and then bromoacetamide further reacts with dimethylamine under alkaline conditions to generate the small molecule peptide mimic:

7. The method for preparing the oxazole ring-containing honokiol-antimicrobial peptide mimic conjugate according to claim 2, characterized in that, In step (8), the molar ratio of intermediate 8 to small molecule peptide mimic 9 is 1:(2.5-3.5), the reaction temperature is 75-85℃, and the reaction solvent is anhydrous ethanol.

8. The use of the oxazole ring-containing and magnolol-antimicrobial peptide mimic conjugate according to claim 1 in the preparation of antimicrobial drugs, characterized in that, The antibacterial drug can inhibit Staphylococcus aureus or methicillin-resistant Staphylococcus aureus.

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