Hydroxypyridone coupled macrolide compound as well as preparation method and application thereof

Abstract

The invention relates to the field of medicines, in particular to a hydroxypyridone coupled macrolide compound shown in a formula (I) or a formula (II) and application of the hydroxypyridone coupled macrolide compound in preparation of an antibacterial agent and a bacterial biofilm inhibitor. In-vivo and in-vitro pharmacological verification shows that most of the hydroxypyridone coupled macrolide compounds have antibacterial activity, can be used for preparing antibacterial agents and anti-biofilm agents, and have the potential of being developed into novel antibacterial drugs.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of medicine, and particularly relates to a class of hydroxypyridinone-coupled erythromycin, azithromycin compounds and a preparation method thereof and application thereof in antibacterial drugs. BACKGROUND

[0002] The abuse of antibiotics and the emergence of "superbugs" have made bacterial resistance a very serious global public health problem. In international epidemiological studies, ICU acquired infection Pseudomonas aeruginosa accounts for as high as 16.2%. Such high mortality and high morbidity are closely related to the drug resistance of Pseudomonas aeruginosa. It is an urgent need to develop new treatment strategies to solve the problem of bacterial resistance caused by Pseudomonas aeruginosa and other bacteria. The World Health Organization predicts that if there is no new and better treatment method, this number may rise to 10 million by 2050. The frequent occurrence of cell drug resistance forces humans to continuously develop new antibiotics with new structures and new targets. However, the development of new antibiotics requires a large amount of time and human and material resources, which poses a major threat to human health and property.

[0003] The iron-iron carrier uptake system provides a way to enter the periplasm through the poorly permeable outer membrane. Based on the unique iron acquisition mechanism of bacteria, the Miller team first proposed the "Trojan horse" strategy in the 1980s, coupling antibiotics with natural iron carriers or synthetic iron carrier molecules, and using the bacterial own iron carrier transport system to target the delivery of antibiotics to the antibacterial target to kill bacteria. The purpose of the "Trojan horse" strategy is to promote the entry of antibiotics into bacterial cells, especially negative bacteria, thereby increasing the antibacterial activity or expanding the antibacterial spectrum. The "Trojan horse" strategy may be an effective solution to the difficulty of penetrating the outer membrane of negative bacteria.

[0004] Hydroxypyridinone iron carriers not only can participate in the regulation and control of Pseudomonas aeruginosa as biofilm inhibitors, but also can act as iron carriers to deliver antibacterial agents to negative bacteria. Macrolide antibiotics are a class of antibacterial agents against positive bacteria, which prevent bacterial growth by inhibiting ribosomes and inhibiting protein synthesis. The representative drugs of macrolide antibiotics are erythromycin and azithromycin. Although azithromycin cannot inhibit the growth of negative bacteria, it is often used in the treatment of chronic Pseudomonas aeruginosa lung infection in cystic fibrosis patients in clinical practice. Therefore, the present application couples a macrolide antibiotic derivative with a hydroxypyridinone iron carrier to invent a new type of antibiotic, which can improve the permeability of the macrolide derivative to gram-negative bacteria, and deliver erythromycin derivatives to Pseudomonas aeruginosa, which may have antibacterial and antibiotic membrane dual effects, and contribute to the full play of macrolide antibiotics in the treatment of pulmonary infection. SUMMARY

[0005] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the present application provides a kind of hydroxypyridinone coupled macrolide compounds, the chemical structure of this kind of compound is stable, and through activity experiment, it has antibacterial and antibiofilm effect, has the antibacterial potential of new type antibiotic.

[0006] In a first aspect, the present application provides a kind of hydroxypyridinone coupled macrolide compounds shown in formula (I) or formula (II) or its pharmaceutically acceptable salt, isomer, solvate or prodrug:

[0007]

[0008] Wherein,

[0009] One of R is The other is hydrogen;

[0010] X is selected from -NHCO-, -O-;

[0011] Y is selected from -NH(CH2) p - or -(CH2) p -;

[0012] Z is selected from -(CH2) q -;

[0013] R1 It is selected from methyl, ethyl, propyl, butyl, hydroxyl, or it is the connecting bond of -XCH2-;

[0014] R2 It is selected from hydrogen, methyl, ethyl, propyl, butyl, hydroxyl, hydroxymethyl, hydroxyethyl;

[0015] n is selected from 2, 3, 4, 5, 6, 7 or 8;

[0016] m is selected from 0, 1, 2 or 3;

[0017] p is selected from 2, 3, 4, 5, 6, 7 or 8;

[0018] q is selected from 0, 1, 2, 3 or 4.

[0019] In one embodiment, X is connected by -CO- with -(CH2) n -.

[0020] In one embodiment, the compound is selected from:

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027] In a second aspect, the present application also provides a method for preparing the hydroxypyridinone-conjugated erythromycin compounds, comprising the following steps:

[0028] (1.1) Synthesis of hydroxypyridinone siderophores: a series of intermediate compounds 1-17 were synthesized from kojic acid as the starting material;

[0029] (1.2) Synthesis of erythromycin derivatives: erythromycin and hydrazine hydrate were refluxed in methanol; the solvent was evaporated under reduced pressure, and the residue was dissolved in a solution of isopropyl alcohol and water, refluxed, stirred until cooled, and filtered after ice bath to obtain white precipitate, which was erythromycin hydrazine derivative 18;

[0030] Erythromycin was used as the starting material, and erythromycin C-9 carbonyl and hydroxylamine hydrochloride were reacted in pyridine solution to obtain erythromycin oxime derivative 19 after purification;

[0031] (1.3) Amide condensation of erythromycin hydrazine derivative 18 and compound 5 or 6 or 13 or 14 was carried out in EDCI, Hobt, DMAP in DMF to obtain a series of intermediates after purification;

[0032] Erythromycin oxime derivative 19 and 1,4-dibromobutane or 1,6-dibromohexane or 1,8-dibromooctane were refluxed in K2CO3, acetone to obtain compounds 20-22 after purification; compounds 20-22 and compounds 2 or 10-12 were reacted in NaH, DMF to obtain a series of intermediates after purification;

[0033] (1.4) Synthesis of erythromycin-hydroxypyridinone conjugates: the intermediates of step 1.3 were treated with H2, 10% Pd / C in methanol overnight to obtain conjugates Z-1, Z-2, Z-3, Z-4, Z-5, Z-6, Z-7, Z-8, Z-9, Z-10, Z-11, Z-12, Z-13, Z-14, Z-15, Z-16 after purification;

[0034] The synthesis route is as follows:

[0035]

[0036] Reagents and conditions: (a)(i) SOCl2, 25℃, 1h; (ii) Zn, HCl, H2O, 70-80℃, 3h, 87%; (b) HCHO, NaOH, H2O, 25℃, overnight, 89%; (c) BnCl, K2CO3, MeOH, 65℃, overnight, 81-88%; (d)(i) THP, TsOH, DCM, 25℃, 1h; (ii) NH2CH3, MeOH, 75℃, overnight; (iii) 2M HCl, EtOH, 75℃, 2h, 67-74%; (e) phthalimide, Ph3P, DEAD, dry THF, 0℃ to 25℃, overnight, 82-83%; (f) N2H4·H2O, EtOH, 75℃, 2h, 78-89%; (g) succinic anhydride or glutaric anhydride,DCM,DMAP,rt.(h)hydroxylamine hydrochloride,MeOH,75℃,phthalimide;

[0037]

[0038] Reagents and conditions: (a) N2H4·H2O, MeOH, 80℃, reflux. (b)(i) carboxyl 5 or 6 or 13 or 14, EDCI, Hobt, DMAP, Dry DMF, rt, overnight; (ii) Pd / C, H2, MeOH, rt, overnight.

[0039]

[0040] Reagents and conditions: (a) N2H4·H2O, MeOH, 75℃, 2h. (b) 1,4-Dibromobutane or 1,6-Dibromohexane or 1,8-Dibromooctane, K2CO3, acetone, 50℃, reflux. (c)(i) hydroxy 2 or 10 or 12 or 15 or 16, NaOH, Dry DMF, rt, overnight; (ii) Pd / C, H2, MeOH, rt, overnight.

[0041]

[0042] Reagents and conditions: (a) N2H4·H2O, MeOH, 75℃, 2h. (b) 1,4-Dibromobutane or 1,6-Dibromohexane or 1,8-Dibromooctane, K2CO3, acetone, 50℃, reflux. (c)(i) hydroxy 11, NaOH, Dry DMF, rt, overnight; (ii) Pd / C, H2, MeOH, rt, overnight.

[0043] (1.5) Synthesis of azithromycin derivatives: Azithromycin and 2'-O-acetylazithromycin derivatives were reacted with succinic anhydride in dry DCM, and DMAP was added. After purification, azithromycin carboxylic acid derivatives 23 and 24 were obtained.

[0044] (1.6) Synthesis of azithromycin-hydroxypyridinone intermediate: The above carboxylic acid derivatives 23 and 24 and hydroxypyridinone derivatives 4 and 12 were acylated in EDCI, Hobt and DMF, and the intermediate was obtained after further purification;

[0045] (1.7) Synthesis of azithromycin-hydroxypyridinone conjugates: The intermediates of step 1.6 were treated overnight in methanol with H2 and 10% Pd / C, and after purification, conjugates Z-17, Z-18, Z-19 and Z-20 were obtained.

[0046] The synthesis circuit is as follows:

[0047]

[0048] Reagents and conditions: (a) succinic anhydride, DMAP, Dry DCM, rt, 12h; (b)(i) amino 4or12, EDCI, Hobt, DMAP, Dry DMF, rt, overnight; (c) 10% Pd / C, H2, MeOH, rt, overnight;

[0049]

[0050] Reagents and conditions: (a) succinic anhydride, DMAP, Dry DCM, rt, 12h; (b)(i) amino4or12, EDCI, Hobt, DMAP, Dry DMF, rt, overnight; (ii) MeOH, 37℃, overnight; (c) 10% Pd / C, H2, MeOH, rt, overnight.

[0051] In a third aspect, the present invention provides the use of the aforementioned hydroxypyridinone-conjugated erythromycin compounds or their pharmaceutically acceptable salts, isomers, solvates or prodrugs in the preparation of antibacterial agents and antibiofilm agents.

[0052] Preferably, the bacteria include Gram-positive bacteria and Gram-negative bacteria.

[0053] Preferably, the Gram-positive bacteria include Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Bacillus subtilis, and Staphylococcus epidermidis.

[0054] Preferably, the Gram-negative bacteria include Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, and Proteus vulgaris.

[0055] In a fourth aspect, the present invention provides a pharmaceutical composition comprising at least one of the hydroxypyridinone-coupled erythromycin compounds or pharmaceutically acceptable salts, isomers, solvates or prodrugs thereof.

[0056] Preferably, the pharmaceutical composition further comprises one or more pharmaceutically acceptable carriers or excipients.

[0057] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0058] (1.1) In this study, starting from the structure of erythromycin, a macrolide antibacterial drug targeting positive bacteria, we successfully synthesized a series of chemically stable erythromycin-hydroxypyridinone conjugates by coupling it with a hydroxypyridinone siderophore at different sites via amide and ether bonds. The antibacterial activity of the compounds against both positive and negative bacteria, including *Pseudomonas aeruginosa*, was determined using the broth serial dilution method. The anti-biofilm inhibitory activity of these compounds against *P. aeruginosa* was detected using crystal violet staining. The experimental results showed that most of the compounds exhibited inhibitory effects on *P. aeruginosa*, and also inhibited *P. aeruginosa* biofilm formation.

[0059] (1.2) In this study, starting from the parent structure of another class of macrolide drugs, azithromycin, a series of chemically stable azithromycin-hydroxypyridinone conjugates were successfully synthesized by coupling it with a hydroxypyridinone siderophore at different sites via amide and ester bonds. The antibacterial activity of these compounds against Pseudomonas aeruginosa, including negative and positive bacteria, was determined using the broth serial dilution method. The antibiofilm activity of these compounds against Pseudomonas aeruginosa was detected using crystal violet staining. Attached Figure Description

[0060] Figure 1 The anti-biofilm activity of the conjugate (Z-5) and erythromycin (Ery.) against Pseudomonas aeruginosa;

[0061] Figure 2 The anti-biofilm activity of the conjugate and azithromycin (AZM) against Pseudomonas aeruginosa PAO1 was studied. Detailed Implementation

[0062] Unless otherwise specified, all reagents used in the examples are commercially available.

[0063] Example 1: Preparation of hydroxypyridinone conjugated with erythromycin compounds (conjugates Z-1, Z-2, Z-3, Z-4)

[0064] Step 1: Preparation of erythromycin hydrazine derivative (intermediate 18)

[0065]

[0066] Erythromycin (1 g, 1.36 mmol) was dissolved in methanol, and 50% hydrazine hydrate (1.32 mL, 13.6 mmol) was added. The mixture was refluxed at 80 °C for 20 h. After evaporating excess solvent under reduced pressure, the residue was dissolved in a mixed solution of isopropanol (6 mL) and water (6 mL), and refluxed at 60 °C for 20 min. The mixture was then stirred for 1 h and cooled to room temperature. The mixture was slowly stirred in an ice bath for 4 h, the precipitate was filtered, washed with ice water, and dried to obtain erythromycin hydrazine derivative 18 as a white solid, yield: 81%.

[0067] Step 2: Preparation of hydroxypyridinone conjugated with erythromycin-like compounds (conjugate Z-1)

[0068]

[0069] Under anhydrous and oxygen-free conditions, compound 5 was dissolved in anhydrous DMF. EDCI and Hobt were added at 0°C, and the mixture was stirred for 30 minutes. Then, erythromycin hydrazine 18 (0.250 g, 0.0001 mol) and DMAP were added, and the mixture was allowed to react overnight at room temperature. After the reaction was complete, the mixture was extracted with dichloromethane, washed twice with water, and the organic phase was dried to remove the solvent. The residue was purified by column chromatography (DCM-MeOH = 3:1, v / v). The residue was collected after evaporating the solvent. The residue was dissolved in 10 mL of methanol, and Pd / C₂ was added for displacement with H₂. The mixture was then reacted overnight at room temperature. After the reaction was complete, the mixture was filtered, and the filtrate was evaporated to dryness. The residue was purified by slurrying with dichloromethane / methanol to give conjugate Z-1. Yield: 40%. 1H NMR(600MHz,DMSO-d6)δ10.31(s,1H),8.48(t,J=5.6Hz,1H),7.42(s,1H),6.19–6.05(m,1H),5.32(s,1H),5.05(t,J=27.9Hz,1H),4.71(d,J=4.9Hz,1H),4.41(t,J=6.9Hz,1H),4.22(d,J=5.5Hz,2H),4.01(dd,J=12.7,7.1Hz,3H),3.82(d,J=9.5Hz,3H),3.73–3.53(m,7H),3.46–3.34(m,2H),3.20(s,3H),3.10–3.03(m,1H),2.89(d,J=9.3Hz,1H),2.83–2.73(m,2H),2.65(d,J=6.8Hz,1H),2.46(dd,J=13.4,3.8Hz,2H),2.32–2.26(m,6H),1.94(dd,J=24.2,17.3Hz,1H),1.81(dd,J=23.9,16.4Hz,1H),1.67–1.47(m,3H),1.38–1.28(m,4H),1.24(t,J=10.3Hz,1H),1.19–0.94(m,27H),0.75(dt,J=23.0,7.3Hz,3H). 13 C NMR(151MHz,DMSO-d6)δ174.94(s),172.22(s),170.84(s),168.34(s),147.24(s),145.78(s),145.70(d,J=22.7Hz),124.88(s),112.64(s),102.15(s),96.09(s),83.29(s),77.83(s),76.38(s),74.09(s),73.79(s),73.10(s),70.90(s),70.38(s),67.18(s),65.36(s),65.09(s),63.26(s),49.32(d,J=5.2Hz),44.40(s),40.53(d,J=17.5Hz),33.06(s),30.65(s),30.41(s),29.77(s),28.58(s),26.42(s),21.88(s),21.35(s),19.42(s),19.15(s),18.99(s),17.04(s),16.48(s),15.77(s),10.96(s),9.71(s).HRMS(ESI)ofcompound Z-1:calcd.for C48 H 81 N5O 16 [M+H] + =984.5751,found[M+H] + =984.5756.

[0070] Example 2: Preparation of hydroxypyridinone coupled with erythromycin-like compounds (coupling Z-2)

[0071] Using compounds 6 (0.201 g, 0.0005 mol) and 18 (1.389 g, 0.02 mol) as raw materials, the same method as compound Z-1 was used to synthesize Z-2, which was a pale yellow solid with a yield of 46%. 1 H NMR(600MHz,DMSO-d6)δ10.26(s,1H),8.44(s,1H),7.41(s,1H),6.10(s,1 H),5.32(s,1H),5.07(d,J=12.1Hz,1H),4.72(d,J=4.8Hz,1H),4.41(d,J= 7.2Hz,1H),4.24–4.17(m,2H),4.06–3.93(m,3H),3.81(d,J=9.7Hz,3H),3 .69(d,J=13.9Hz,3H),3.59(d,J=7.6Hz,4H),3.42–3.38(m,1H),3.27(s,1 H),3.20(s,3H),3.05(dd,J=18.3,10.8Hz,1H),2.89(d,J=9.2Hz,1H),2.8 0(dd,J=22.0,14.5Hz,1H),2.31–2.17(m,10H),1.93(dd,J=24.3,17.5Hz, 1H),1.81(dt,J=32.0,16.0Hz,3H),1.65–1.44(m,3H),1.39–1.27(m,4H), 1.24(d,J=14.7Hz,1H),1.19–0.83(m,27H),0.75(dt,J=23.6,7.4Hz,3H). 13C NMR (151MHz, DMSO-d6) δ175.02(s),172.57(d,J=8.9Hz),170.84(s),168.77(s),147.22(s),145.73(s),124.92(s),112.39(s),102.18( s),96.01(s),83.33(s),77.82(s),76.40(s),74.09(s),73.76(s),73.11(s),70.98(s),70.34(s),67.22(s),65.34(s),65.06(s),63.2 5(s),49.28(s),44.42(s),40.64(s),35.26(d,J=14.5Hz),33.70(s),33.09(s),30.38(s),28.64(s),26.36(s),21.84(d,J=13.0Hz),21 .50(s),21.29(d,J=19.5Hz),20.64(d,J=4.8Hz),19.53(s),19.07(s),17.03(s),16.46(s),15.82(s),10.95(s),9.70(s).HRMS(ESI)of compound Z-2:calcd.for C 49 H 83 N5O 16 [M+H] + =998.5908,found[M+H] + =998.5917.

[0072] Example 3: Preparation of hydroxypyridinone conjugated with erythromycin-like compounds (conjugate Z-3)

[0073] Using compounds 13 (0.201 g, 0.0005 mol) and 18 (1.389 g, 0.02 mol) as raw materials, the same method as compound Z-1 was used to synthesize Z-3, which was a pale yellow solid with a yield of 43%. 1H NMR(600MHz,DMSO-d6)δ10.32(s,1H),8.35–8.17(m,1H),6.14(s,1H),5.29(s,1H),5.07(d,J=11.5Hz,1H),4.70(s,1H),4.49–4.38(m,3H),4.05–3.98(m,2H),3.81(d,J=9.3Hz,3H),3.50–3.38(m,5H),3.33–3.25(m,1H),3.20(s,3H),3.05(dd,J=17.3,9.3Hz,1H),2.88(d,J=9.1Hz,1H),2.80(dd,J=22.6,14.4Hz,2H),2.65(d,J=6.7Hz,1H),2.45(dd,J=17.3,5.6Hz,2H),2.38(d,J=4.9Hz,2H),2.29(s,1H),2.28(s,2H),2.26(d,J=5.8Hz,6H),2.03–1.87(m,1H),1.87–1.75(m,1H),1.66–1.46(m,3H),1.40–1.21(m,7H),1.04(ddt,J=44.2,33.7,17.5Hz,27H),0.78–0.69(m,3H). 13 C NMR(151MHz,DMSO-d6)δ174.98(s),172.20(s),169.85(s),168.43(s),146.39(d,J=57.8Hz),146.19–146.05(m),129.36(d,J=18.1Hz),112.83(s),102.22(s),96.13(s),83.23(s),79.14(s),77.86(s),76.41(s),74.06(s),73.88(s),73.11(s),67.25(s),65.23(d,J=41.4Hz),64.98(s),49.31(s),44.39(s),40.66(s),36.03(s),35.33(s),34.54(s),30.47(d,J=26.4Hz),29.71(s),28.60(s),26.46(s),21.87(d,J=13.5Hz),21.25(s),20.74(s),19.50(s),19.16(s),19.02(s),17.06(s),16.46(s),15.74(s),11.06(d,J=22.7Hz),9.72(s).HRMS(ESI)of compound Z-3:calcd.for C49 H 83 N5O 16 [M+H] + =998.5908,found[M+H] + =998.5918.

[0074] Example 4: Preparation of hydroxypyridinone conjugated with erythromycin-like compounds (conjugate Z-4)

[0075] Using compounds 14 (0.201 g, 0.0005 mol) and 18 (1.389 g, 0.02 mol) as raw materials, the same method as compound Z-1 was used to synthesize Z-4, which was a pale yellow solid with a yield of 48%. 1 H NMR(600MHz,DMSO-d6))δ10.23(s,1H),8.23(dd,J=19.0,14.0Hz,1H),6.13( s,1H),5.75(s,1H),5.34(s,1H),5.07(d,J=11.3Hz,1H),4.72(d,J=4.7Hz,1 H), 4.43 (dd, J=13.3, 8.7Hz, 3H), 4.01 (dd, J=15.3, 6.4Hz, 2H), 3.81 (d, J=9. 6Hz,2H),3.67(d,J=10.2Hz,2H),3.47(s,3H),3.43–3.38(m,1H),3.20(s,3H) ),3.10–3.02(m,1H),2.90(d,J=9.4Hz,1H),2.83–2.75(m,1H),2.65(d,J=6. 8Hz,1H),2.28(s,9H),2.23(dd,J=18.6,10.7Hz,2H),2.20–2.15(m,2H),1.9 4(dd,J=24.1,17.2Hz,1H),1.86–1.72(m,3H),1.56(ddd,J=27.5,24.3,6.6H z,3H),1.44–1.19(m,7H),1.18–0.95(m,27H),0.74(dq,J=22.2,7.4Hz,3H). 13C NMR(151MHz,DMSO-d6)δ174.96(s),172.51(s),169.86(s),168.80(s),146. 53(s),146.24(s),129.34(s),112.82(s),102.17(s),96.06(s),83.35(s), 79.11(s),77.84(s),76.40(s),74.10(s),73.76(s),73.10(d,J=4.7Hz),67 .20(s),65.36(s),65.09(s),63.27(s),55.38(s),49.30(s),44.41(s),40. 62(s),36.07(s),35.24(d,J=27.6Hz),34.51(s),33.76(s),33.07(s),30.4 1(s),28.62(s),26.35(s),21.85(d,J=15.7Hz),21.53(s),21.41(s),21.30 (d,J=21.3Hz),20.73(s),19.56(s),19.06(d,J=21.1Hz),18.97–18.75(m), 17.03(s),16.48(s),15.81(s),11.16(s),10.96(s),9.72(s).HRMS(ESI)of compound Z-4:calcd.for C 50 H 85 N5O 16 [M+H] + =1212.6064, found[M+H] + =1012.6077.

[0076] Example 5: Preparation of hydroxypyridinone conjugated with erythromycin-like compounds (conjugate Z-5)

[0077] Step 1: Preparation of erythromycin oxime (intermediate 19)

[0078]

[0079] Erythromycin was added to a pyridine solution, dissolved, and then hydroxylamine hydrochloride was added. The mixture was stirred at room temperature for 72 hours. After the reaction was complete, the mixture was evaporated under reduced pressure. The residue was extracted with dichloromethane, washed three times with saturated sodium chloride aqueous solution, and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure, and the product was precipitated by adding n-hexane, resulting in a white solid. 1H NMR (400MHz, DMSO-d6) δ10.60(s,1H),5.12(d,J=11.2Hz,1H),4.73(d,J=4.9Hz,1H),4.39(d,J=7.3Hz,1H),4.30(d,J=7 .4Hz,1H),4.12(s,1H),4.02(dd,J=11.8,5.5Hz,3H),3.86(d,J=9.0Hz,1H),3.70–3.62(m,1H),3.52–3.45(m,3H),3.21( s,3H),3.03(t,J=7.6Hz,1H),2.93–2.87(m,1H),2.82–2.74(m,1H),2.21(s,6H),1.93–1.78(m,2H),1.61–1.45(m,4H), 1.45–1.35(m,2H),1.33(s,4H),1.17–1.12(m,7H),1.08(t,J=5.8Hz,11H),1.01(d,J=7.1Hz,9H),0.75(t,J=7.4Hz,3H).

[0080] Step 2: Preparation of erythromycin 9-O-4-bromooxime ether derivative (intermediate 20)

[0081]

[0082] Erythromycin oxime (3 g, 4 mmol) was dissolved in 30 mL of acetone, and K2CO3 (2.2 g, 16 mmol) was added and stirred for 30 minutes. 1,4-Dibromobutane (952 μL, 8 mmol) was added to the mixture, and the mixture was heated to 50 °C and refluxed for 12 h. After the reaction was completed, the solvent was evaporated, and the mixture was purified by column chromatography (DCM:MeOH = 40:1) to give intermediate 20 as a white solid, yield: 78%. 1 H NMR (400MHz, DMSO-d6) δ5.12(d,J=9.9Hz,1H),4.73(s,1H),4.33(d,J=48.2Hz,2H ),3.98(d,J=23.0Hz,8H),3.58(s,4H),3.42(s,1H),3.21(s,3H),3.02(s,1H),2. 90(s,1H),2.76(s,1H),2.67(s,1H),2.22(s,6H),1.79(d,J=69.2Hz,7H),1.54(d d,J=33.4,18.3Hz,4H),1.30(s,3H),1.09(dd,J=41.2,19.4Hz,27H),0.75(s,3H).

[0083] Preparation of erythromycin 9-O-6-bromooxime ether derivative (intermediate 21)

[0084] Using erythromycin oxime (0.5 g, 0.66 mmol) and 1,6-dibromohexane (206 μL, 1.33 mmol) as starting materials, the same method as intermediate 20 was used to synthesize intermediate 21, which was a white solid with a yield of 71%. 1 H NMR(400MHz, CDCl3)δ5.06(d,J=10.8Hz,1H),4.90(s,1H),4.79–4.55(m,1H),4.42(d,J=6.9Hz, 1H),4.06–3.95(m,2H),3.77(s,1H),3.66(s,1H),3.58–3.45(m,2H),3.30(s,3H),3.27(d,J=9.0 Hz,1H),3.06–2.73(m,3H),2.69–2.45(m,3H),2.37(s,6H),2.32(d,J=6.4Hz,1H),2.13–1.82(m, 3H),1.81–1.39(m,9H),1.38–1.06(m,28H),1.03(d,J=6.4Hz,3H),0.83(dd,J=16.0,9.0Hz,3H).

[0085] Preparation of erythromycin 9-O-8-bromooxime ether derivative (intermediate 22)

[0086] Using erythromycin oxime (0.5 g, 0.66 mmol) and 1,8-dibromooctane (242 μL, 1.33 mmol) as starting materials, the same method as intermediate 20 was used to synthesize intermediate 22, which was a white solid with a yield of 73%. 1H NMR (400MHz, CDCl3) δ5.10(d,J=10.9Hz,1H),4.91(d,J=4.5Hz,1H),4.43(d,J=7.2Hz,2H),4.01(dd,J=12.1,5.5Hz,4H),3.67(s,2H), 3.58(d,J=7.3Hz,1H),3.50(dd,J=10.2,5.3Hz,1H),3.41(t,J=6.8Hz,2H),3.31(s,3H),3.27–3.21(m,1H),3.10(s,1H),3.02(t,J=9. 5Hz,1H),2.93–2.87(m,1H),2.49(t,J=9.5Hz,1H),2.33(s,6H),2.24(d,J=10.0Hz,1H),2.03–1.81(m,8H),1.80(s,1H),1.62(ddd,J= 20.8,17.5,11.9Hz,7H),1.46(s,6H),1.39(dd,J=13.9,6.9Hz,3H),1.31–1.05(m,24H),1.02(d,J=6.9Hz,3H),0.83(t,J=7.3Hz,3H).

[0087] Step 3: Preparation of erythromycin 9-O-oxime ether-hydroxypyridinone conjugated with erythromycin-like compounds (conjugate Z-5)

[0088]

[0089] Under anhydrous and oxygen-free conditions, compound 2 was dissolved in anhydrous DMF, and NaH was added at 0°C. After stirring for 1 h, intermediate 20 was added to the reaction flask, and the reaction was carried out overnight at room temperature. After the reaction was complete, the mixture was extracted with dichloromethane, washed with water, washed three times with saturated sodium chloride aqueous solution, dried over anhydrous sodium sulfate, evaporated to dryness, and separated by column chromatography to obtain the benzyl-protected precursor. This precursor was dissolved in 10 mL of methanol, Pd / C, and H2 was added for displacement, followed by reaction at room temperature overnight. After the reaction was complete, the mixture was filtered, the filtrate was evaporated to dryness, and the residue was purified by slurrying with dichloromethane / methanol to give coupling compound Z-5 as a yellow solid. Yield: 43%. 1H NMR(400MHz,DMSO-d6))δ7.45(s,1H),6.29(s,1H),5.75(s,1H),5.10(d,J=10.4Hz,1H),4.72(d,J=3.8Hz,1H),4.48–4.37(m,3H),4.29–4.17(m,1H),4.05–3.99(m,2H),3.92(s,1H),3.85(d,J=9.1Hz,3H),3.70(s,1H),3.63(s,2H),3.45(s,2H),3.21(d,J=10.8Hz,3H),3.14(s,2H),3.03(d,J=10.8Hz,1H),2.91(t,J=9.3Hz,1H),2.75(dd,J=16.6,8.6Hz,1H),2.63(s,6H),2.25(d,J=14.8Hz,1H),1.97(s,1H),1.92(d,J=7.2Hz,2H),1.60(s,4H),1.53–1.23(m,9H),1.18–0.92(m,30H),0.73(t,J=7.3Hz,3H). 13 C NMR(101MHz,DMSO-d6))δ177.97(s),175.34(s),172.41(s),170.81(s),169.94(s),125.90(s),113.96(s),101.61(s),95.84(s),83.68(s),78.67(s),77.69(s),76.38(s),74.23(s),73.03(d,J=11.8Hz),70.15(s),68.46(s),66.62(s),65.31(d,J=15.3Hz),60.22(s),49.56–48.89(m),44.68(s),37.69(s),35.21(s),31.14(s),29.49(s),26.54(s),26.02(d,J=19.2Hz),21.91–20.97(m),19.34(d,J=11.9Hz),18.95(s),18.46(s),17.44(s),15.78(d,J=103.3Hz),15.27–14.70(m),14.55(s),12.16(s),11.13(d,J=12.1Hz),9.55(s).HRMS(ESI)of compound Z-5:calcd.forC 49 H 85 N3O 15 [M+H] +=956.6053,found[M+H] + =956.6063.

[0090] Example 6: Preparation of hydroxypyridinone coupled with erythromycin-like compounds (coupling Z-6)

[0091] Using compound 10 and intermediate 20 as starting materials, the same synthesis method as compound Z-5 was employed to obtain coupling compound Z-6, a brownish-yellow solid. Yield: 41%. 1 H NMR (600MHz, DMSO-d6) δ5.78(s,1H),5.41–5.23(m,1H),5.13(d,J=10.1Hz,1H),4.74(s,1H),4.54(s,1H),4.46(d,J=6.7Hz,1H),4.40(dd,J =33.6,7.3Hz,1H),4.30(d,J=7.2Hz,1H),4.15–4.06(m,1H),3.94(d,J=23.5Hz,4H),3.88(d,J=8.1Hz,1H),3.67(d,J=63.6Hz,3H),3.38(d,J =29.2Hz,12H),3.24–3.14(m,3H),3.06(s,1H),2.92(d,J=7.5Hz,1H),2.78(s,1H),2.67(s,4H),2.27(d,J=14.9Hz,1H),1.95(d,J=38.0Hz,2 H),1.82(s,1H),1.62–1.53(m,2H),1.43(ddd,J=28.9,16.3,7.1Hz,5H),1.13(dddd,J=54.4,47.9,23.3,7.2Hz,30H),0.74(t,J=7.1Hz,3H). 13C NMR(151MHz,DMSO-d6)δ175.37(s),174.98(s),169.83(s),147.57(s),124.72(s),118.91(s),101.72(s),95.85(s),83.86(s),78.67( s),77.74(s),76.39(s),74.31(s),73.31(s),73.12(s),70.86(s),70.19(s),69.57(s),66.68(s),65.42(d,J=6.9Hz),65.20(s),61.14 (s),49.34(s),44.76(s),35.21(s),34.95(s),34.76(s),31.76(s),31.62(s),30.82(s),30.29(s),29.89(s),29.70–29.16(m),29.16– 29.07(m),25.76(s),22.56(s),21.79–21.09(m),19.16(d,J=56.2Hz),17.49(s),16.36(s),14.43(s),11.11(s),9.58(s).HRMS(ESI)of compound Z-6:calcd.for C 49 H 85 N3O 15 [M+H] + =972.6003, found[M+H] + = 972.6012.

[0092] Example 7: Preparation of hydroxypyridinone coupled with erythromycin-like compounds (coupling Z-7)

[0093] Using compound 2 and intermediate 21 as starting materials, the same synthesis method as compound Z-5 was used to obtain coupling compound Z-7, which was a brownish-yellow solid. Yield: 43%. 1H NMR(400MHz,DMSO-d6))δ7.44(s,1H),6.24(s,1H),5.11(d,J=10.6Hz,2H),4.74(s,2H),4.45–4.33(m,3H),4.04–3.98(m,2H),3.91(dd,J=14.4,7.9Hz,4H),3.61(s,2H),3.39(dd,J=16.9,10.5Hz,4H),3.22(d,J=10.7Hz,3H),3.16(s,2H),2.92(t,J=9.5Hz,1H),2.76(dd,J=15.5,7.6Hz,1H),2.65(d,J=6.9Hz,1H),2.42–2.24(m,6H),1.95–1.87(m,1H),1.82(dd,J=12.3,7.4Hz,1H),1.72(d,J=9.8Hz,1H),1.59–1.38(m,8H),1.30(s,4H),1.24(d,J=9.6Hz,4H),1.20–1.03(m,23H),1.02–0.98(m,7H),0.75(d,J=14.4Hz,3H). 13 C NMR(101MHz,DMSO-d6)δ175.35(s),170.83(s),169.94(s),125.62(s),113.88(s),101.70(s),95.86(s),83.65(s),78.69(s),77.69(s),76.39(s),74.31(s),73.03(d,J=13.0Hz),69.93(d,J=40.7Hz),68.51(s),66.68(s),65.44(s),65.22(s),60.23(s),49.33(s),49.01(s),44.71(s),35.23(s),31.07(s),28.61(s),26.76–26.62(m),26.24(dd,J=43.6,16.7Hz),21.45(dd,J=28.3,13.1Hz),19.28(s),18.96(s),18.50(s),17.44(s),16.32(s),15.27(s),14.55(s),12.86(s),12.20(s),11.34–10.84(m),9.56(s).HRMS(ESI)of compound Z-7:calcd.for C 50 H 87 N3O 16 [M+H] +=986.6159, found[M+H] + =986.6161.

[0094] Example 8: Preparation of hydroxypyridinone conjugated with erythromycin-like compounds (conjugate Z-8)

[0095] Using compound 10 and intermediate 22 as starting materials, the same synthetic method as compound Z-5 was employed to obtain conjugate Z-8, a yellowish-brown solid. Yield: 40%. 1 H NMR (600MHz, DMSO) δ5.12(d,J=10.1Hz,1H),4.74(d,J=4.2Hz,1H),4.45(dd,J=1 6.0,8.8Hz,2H),4.31(d,J=6.1Hz,2H),4.12(s,2H),3.94(ddd,J=28.4,18.5,8. 6Hz,7H),3.67(dd,J=56.6,9.6Hz,4H),3.51(s,1H),3.39–3.35(m,5H),3.23(d, J=20.2Hz,4H),3.17(s,1H),3.09(s,1H),2.85(dd,J=75.2,5.9Hz,4H),2.65(d,J =6.6Hz,2H),2.27(d,J=14.9Hz,1H),2.20–2.10(m,1H),1.92(d,J=10.6Hz,2H), 1.82(dd,J=20.3,8.0Hz,2H),1.52(ddd,J=33.9,27.1,7.4Hz,5H),1.43–1.38(m, 3H),1.30(d,J=7.6Hz,6H),1.25(d,J=14.1Hz,5H),1.12(ddd,J=19.7,17.7,6.4 Hz,15H),1.03–0.99(m,6H),0.86(dd,J=16.6,7.3Hz,2H),0.75(t,J=7.3Hz,3H). 13C NMR(151MHz, DMSO)δ175.38(s),174.78(s),172.57(s),169.89(s),147.57(s),124.75(d,J=10.0Hz),118.91(s),101.95(s),95.91(s),83.48(s) ),78.73(s),77.77(s),76.41(s),74.37(s),73.30(s),73.12(s),70.13 (d,J=16.9Hz),66.96(s),65.27(d,J=40.0Hz),65.13–64.95(m),61.12( s),60.71(s),49.34(s),49.06(s),44.71(s),35.25(s),32.96(s),31.6 2(s),30.29(s),29.55(s),29.26(d,J=62.0Hz),25.88(d,J=5.2Hz),22. 57(s),21.63(d,J=8.1Hz),21.40(d,J=9.5Hz),19.29(s),19.00(s),17. 46(s),16.30(s),15.26(s),14.43(s),11.10(s),9.58(s).HRMS(ESI)of compound Z-8:calcd.for C 51 H 89 N3O 16 [M+H] + =1000.6316,found[M+H] + =1000.6326.

[0096] Example 9: Preparation of hydroxypyridinone conjugated with erythromycin-like compounds (conjugate Z-9)

[0097] Using compound 2 and intermediate 22 as starting materials, the same synthetic method as compound Z-5 was used to obtain conjugate Z-9, a yellow solid. Yield: 45%. 1H NMR(600MHz,DMSO)δ7.40(dd,J=26.7,18.1Hz,1H),6.24(s,1H),5.12(d,J=10.5Hz,2H),4.74(s,2H),4.53–4.30(m,3H),4.06–3.85(m,6H),3.81–3.58(m,6H),3.45–3.34(m,12H),3.27–3.14(m,4H),3.09(s,1H),2.95–2.70(m,4H),2.64(d,J=6.4Hz,1H),2.27(d,J=14.9Hz,2H),1.84(dd,J=33.0,27.5Hz,4H),1.60–1.45(m,4H),1.38–1.22(m,13H),1.19–1.05(m,11H),1.03–0.98(m,4H),0.78(dd,J=38.0,30.8Hz,3H). 13 C NMR(151MHz,DMSO)δ175.41(s),170.83(s),169.88(d,J=3.9Hz),147.59(s),125.05(s),113.96(s),101.97(s),95.90(s),83.46(s),78.70(s),77.82(d,J=12.7Hz),76.42(s),74.38(s),73.33(s),73.13(s),70.22(d,J=8.1Hz),68.58(s),66.99(s),65.39(s),65.13(s),61.18(s),49.35(s),44.73(s),35.24(s),33.02(s),31.62(s),30.29(s),29.51–29.04(m),29.01(s),25.96(d,J=13.4Hz),22.57(s),21.84–21.68(m),21.51(d,J=41.7Hz),19.28(s),19.00(s),17.47(s),16.30(s),15.25(s),14.43(s),11.11(s),9.57(s).HRMS(ESI)of compound Z-9:calcd.for C 52 H 91 N3O 16 [M+H] + =1014.6472,found[M+H] + =1012.6473.

[0098] Example 10: Preparation of hydroxypyridinone coupled with erythromycin-like compounds (coupling Z-10)

[0099] Using compound 10 and intermediate 22 as starting materials, the same synthetic method as compound Z-5 was employed to obtain conjugate Z-10, a pale red solid. Yield: 43%. 1 H NMR (400MHz, DMSO-d6) δ7.41(s,1H),4.97–4.35(m,1H),4.33–4.02(m,2H),3.98(dd,J=20.3,13.3Hz,2H),3.88(s,2H ),3.74(s,1H),3.66–3.57(m,2H),3.57–3.47(m,2H),3.45–3.31(m,2H),3.24(d,J=7.0Hz,1H),3.19(d,J=18.3Hz,3H) ,3.09(d,J=15.9Hz,3H),2.62(d,J=23.2Hz,6H),2.32–2.21(m,1H),2.20–1.94(m,2H),1.90(s,1H),1.88–1.73(m,3H) ,1.55(s,4H),1.30(d,J=9.7Hz,11H),1.23–0.95(m,30H),0.84(dt,J=15.1,7.6Hz,3H),0.75(dd,J=13.8,6.8Hz,1H). 13C NMR(101MHz,DMSO-d6)δ174.64(s),173.28(s),129.70(s),128.71–128.19(m),123.96(s),83.27(s),77.33(s),75.95(s),75.40(s),73.98 (s),72.75(s),69.86(s),68.02(s),67.82(s),65.10(s),64.77(s),4 8.98(s),45.51(s),41.56(s),35.72(s),33.79(s),32.17(s),31.41(s) ),30.16–29.56(m),28.80(dd,J=34.8,19.1Hz),26.32(s),25.50(s),24.61(s),22.21(s),21.04(d,J=5.3Hz),20.03(s),19.50(s),18.89(s) ),18.58(s),18.08(s),17.68(s),17.03(s),15.96(s),14.04(s),13.54(s),11.11(s),10.71(s),9.32(d,J=25.4Hz).HRMS(ESI)ofcompound Z-10:calcd.for C 53 H 93 N3O 16 [M+H] + =1028.6629, found[M+H] + =1028.6636.

[0100] Example 11: Preparation of hydroxypyridinone coupled with erythromycin-like compounds (coupling Z-11)

[0101] Using compound 15 and intermediate 20 as starting materials, the same synthetic method as compound Z-5 was employed to obtain conjugate Z-11, a yellow solid. Yield: 43%. 1H NMR (600MHz, DMSO) δ7.69(s,1H),7.32(s,1H),6.21(s,1H),5.11(s,1H),4.73(s,2H),4.41(d,J=57 .6Hz,5H),4.22(s,2H),4.08–3.83(m,7H),3.74–3.56(m,3H),3.41(s,2H),3.23(d,J=37.6Hz,4H),3 .02(s,1H),2.90(d,J=7.7Hz,1H),2.77(s,1H),2.65(s,6H),2.26(d,J=14.5Hz,1H),2.03–1.84(m, 3H), 1.77 (d, J=44.7Hz, 2H), 1.64–1.23 (m, 8H), 1.08 (ddd, J=56.9, 39.8, 14.5Hz, 22H), 0.74 (s, 3H). 1 H NMR (600MHz, DMSO) δ7.69(s,1H),7.32(s,1H),6.21(s,1H),5.11(s,1H),4.73(s,2H),4.41(d,J=57.6H z,5H),4.22(s,2H),4.08–3.83(m,7H),3.74–3.56(m,3H),3.41(s,2H),3.23(d,J=37.6Hz,4H),3.02(s ,1H),2.90(d,J=7.7Hz,1H),2.77(s,1H),2.65(s,6H),2.26(d,J=14.5Hz,1H),2.03–1.84(m,3H),1.77 (d,J=44.7Hz,2H),1.64–1.23(m,8H),1.08(ddd,J=56.9,39.8,14.5Hz,22H),0.74(s,3H).HRMS(ESI)of compound Z-11:calcd.for C 47 H 81 N3O 17 [M+H] + =960.5639, found[M+H] + =960.5645.

[0102] Example 12: Preparation of hydroxypyridinone coupled with erythromycin-like compounds (coupling Z-12)

[0103] Using compound 15 and intermediate 21 as starting materials, the same synthetic method as compound Z-5 was employed to obtain conjugate Z-12, a yellow solid. Yield: 43%. 1H NMR(400MHz,DMSO-d6)δ6.24(s,1H),5.57(s,1H),4.99(s,2H),4.87–4.74(m,1H),4.63–4.49(m,2H),4.37(s,3H),4.06–4.01(m,1H),3.74(s,1H),3.59(d,J=1.4Hz,3H),3.38(s,10H),3.24(d,J=11.3Hz,3H),3.16(s,1H),2.94(s,1H),2.66(d,J=10.4Hz,1H),2.15(s,1H),1.94–1.89(m,2H),1.84(t,J=5.3Hz,9H),1.74(d,J=1.7Hz,16H),1.59–1.47(m,2H),1.43–1.31(m,2H),1.21(dd,J=37.7,19.5Hz,7H),1.10(s,2H),1.02(s,2H),0.95(d,J=6.1Hz,1H),0.88–0.76(m,3H). 13 C NMR(101MHz,DMSO-d6)δ179.65(s),175.35(d,J=6.3Hz),170.80(s),169.89(s),110.86(s),108.90(s),101.59(s),95.84(s),83.66(s),79.51(s),78.63(s),77.68(s),76.40(s),74.32(s),73.08(s),70.21(s),69.51(s),66.59(s),65.32(d,J=22.0Hz),65.15–64.58(m),60.22(s),57.98(s),56.91(s),49.32(s),44.67(s),35.18(s),31.12(s),28.81(s),27.69(s),26.95–26.73(m),26.73–25.39(m),25.39–25.19(m),21.30(d,J=14.4Hz),19.24(s),18.93(s),17.42(s),16.28(s),15.26(s),14.53(s),11.05(s),9.54(s).HRMS(ESI)of compound Z-12:calcd.forC 49 H 85 N3O 17 [M+H] + =988.5952,found[M+H] + =988.5955.

[0104] Example 13: Preparation of hydroxypyridinone coupled with erythromycin-like compounds (coupling Z-13)

[0105] Using compound 15 and intermediate 22 as starting materials, the same synthetic method as compound Z-5 was employed to obtain conjugate Z-13, which was a red solid. Yield: 43%. 1 H NMR(400MHz,DMSO-d6)δ7.59(s,1H),6.03(s,1H),4.96(s,2H),4.58(s,2H),4.30(s,4H),4.02(s,2H),3.79(s,6H),3.57(s,3H),3.27(s ,2H),3.05(s,4H),2.82(d,J=55.9Hz,2H),2.35(s,2H),2.11(s,1H),1.80(s,4H),1.43(s,4H),1.16(s,12H),0.95(s,27H),0.59(s,3H). 13 CNMR(101MHz,DMSO-d6)δ174.99(s),173.62(s),130.04(s),128.78(s),126.60(s),124.31(s),83.61(s),77.68(s),76.4 4(s),75.74(s),74.33(s),73.04(d,J=11.1Hz),70.19(s),68.37(s),68.16(s),65.45(s),65.11(s),49.33(s),45.85(s) ,36.07(s),34.14(s),32.51(s),31.75(s),30.51–29.90(m),29.32(d,J=30.9Hz),25.84(s),24.95(s),22.55(s),21.36( s),20.38(s),18.92(s),18.02(s),17.38(s),16.30(s),14.39(s),12.16(s),11.45(s),11.05(s),9.79(s).HRMS(ESI)of compound Z-13:calcd.for C 51 H 89 N3O 17 [M+H] + =1016.6265,found[M+H] + =1016.6272.

[0106] Example 14: Preparation of hydroxypyridinone coupled with erythromycin-like compounds (coupling Z-14)

[0107] Using compound 16 and intermediate 20 as starting materials, the same synthetic method as compound Z-5 was employed to obtain conjugate Z-14, a brownish-yellow solid. Yield: 43%. 1 H NMR (600MHz, DMSO-d6) δ7.28(s,2H),6.16(s,2H),5.12(d,J=10.7Hz,1H),4.74(d,J=4.6Hz,1H),4.45(d,J=7.1Hz,1H),4.35(s,6H),3.93 (d,J=2.0Hz,3H),3.42(dd,J=15.3,9.2Hz,3H),3.24(s,1H),3.21(d,J=5.5Hz,3H),3.16(d,J=3.0Hz,1H),2.93(t,J=11.2Hz,2H),2.83–2 .76(m,1H),2.58(d,J=6.1Hz,6H),2.27(d,J=14.9Hz,1H),1.92(d,J=13.3Hz,1H),1.82(dd,J=12.0,7.9Hz,2H),1.62–1.45(m,5H),1.36– 1.28(m,4H),1.24(dd,J=16.0,4.0Hz,2H),1.19–1.04(m,18H),1.01(dd,J=12.7,5.1Hz,6H),0.90(t,J=7.4Hz,3H),0.75(t,J=7.4Hz,3H). 13 C NMR (151MHz, DMSO-d6) δ175.38 (s), 169.87 (s), 147.43 (d, J = 195.4Hz), 129.70 (s), 128.92 (s), 109.19 (s), 101.84 (s), 98. 01(s),95.89(s),78.73(s),77.75(s),76.41(s),74.89(s),74.34(s),73.12(s),70.20(s),68.30(s),66.88(s),65.41(s) ,65.13(s),63.25(s),61.14(s),60.14(s),49.34(s),35.22(s),31.16(s),29.52(s),26.50(s),25.76(s),21.59(s),21.3 6(s),20.93(s),19.26(d,J=10.4Hz),18.93(d,J=16.2Hz),17.45(s),14.36(s),11.09(s),9.56(s).HRMS(ESI)ofcompound Z-14:calcd.for C 47 H82 N3O 17 [M+H] + =960.5639, found[M+H] + =960.5647.

[0108] Example 15: Preparation of hydroxypyridinone coupled with erythromycin-like compounds (coupling Z-15)

[0109] Using compound 16 and intermediate 21 as starting materials, the same synthetic method as compound Z-5 was employed to obtain conjugate Z-15, a yellowish-brown solid. Yield: 39%. 1 H NMR (600MHz, DMSO) δ7.28(s,2H),6.16(s,2H),5.12(d,J=10.7Hz,1H),4.74(d,J=4.6Hz,1H),4.45(d,J=7.1Hz,1H),4.34(s,6H),3.93(d ,J=2.0Hz,3H),3.41(dd,J=15.3,9.2Hz,3H),3.24(s,1H),3.21(d,J=5.5Hz,3H),3.16(d,J=3.0Hz,1H),2.92(t,J=11.2Hz,2H),2.82–2.7 5(m,1H),2.58(d,J=6.1Hz,6H),2.27(d,J=14.9Hz,1H),1.91(d,J=13.3Hz,1H),1.82(dd,J=12.0,7.9Hz,2H),1.62–1.44(m,5H),1.35–1 .28(m,4H),1.23(dd,J=16.0,4.0Hz,2H),1.18–1.03(m,17H),1.00(dd,J=12.7,5.1Hz,6H),0.89(t,J=7.4Hz,3H),0.74(t,J=7.4Hz,3H). 13C NMR (151MHz, DMSO) δ174.99 (s), 169.47 (s), 147.03 (d, J = 195.4Hz), 129.31 (s), 128.52 (s), 108.79 (s), 101.44 (s), 97.6 1(s),95.49(s),78.33(s),77.35(s),76.01(s),74.49(s),73.94(s),72.72(s),69.80(s),67.91(s),66.48(s),65.02( s),64.74(s),62.85(s),60.74(s),59.75(s),48.95(s),34.82(s),30.76(s),29.12(s),26.11(s),25.36(s),21.19(s) ,20.96(s),20.54(s),18.86(d,J=10.4Hz),18.53(d,J=16.2Hz),17.05(s),13.96(s),10.70(s),9.17(s).HRMS(ESI)of compound Z-15:calcd.for C 49 H 85 N3O 17 [M+H] + =988.5952,found[M+H] + =988.5957.

[0110] Example 16: Preparation of hydroxypyridinone coupled with erythromycin-like compounds (coupling Z-16)

[0111] Using compound 15 and intermediate 22 as starting materials, the same synthesis method as compound Z-5 was employed to obtain conjugate Z-16, a dark brown solid. Yield: 37%. 1H NMR(600MHz,DMSO)δ11.19(s,2H),7.26(s,2H),6.13(s,2H),5.76(s,1H),5.31(s,1H),5.12(d,J=9.4Hz,1H),4.74(s,1H),4.55–4.39(m,2H),4.34(s,6H),4.02(dd,J=13.5,6.5Hz,3H),3.68(s,9H),3.37(d,J=6.8Hz,3H),3.22(d,J=15.2Hz,3H),3.17(s,1H),3.13(s,1H),3.08(s,1H),2.98(s,4H),2.75(d,J=24.3Hz,2H),2.63(d,J=15.8Hz,2H),2.39(s,1H),2.27(d,J=15.0Hz,1H),2.19–2.11(m,1H),1.99(s,1H),1.91(s,1H),1.82(s,1H),1.75(d,J=20.6Hz,1H),1.52(dd,J=35.6,21.4Hz,4H),1.27(dd,J=35.1,10.9Hz,8H),1.20–1.04(m,10H),1.05–0.90(m,5H),0.89–0.70(m,3H). 13 C NMR(151MHz,DMSO)δ180.43(s),179.25(s),177.00(s),176.57(s),174.10(s),147.83(s),146.89(s),117.52(s),78.71(s),78.00(s),77.67(d,J=35.6Hz),76.42(s),73.16(s),70.23(s),68.20(s),67.06(s),65.38(s),64.60(s),60.21–60.01(m),59.92(s),52.47(s),49.35(s),33.02(s),22.57(s),21.54(s),21.31(d,J=19.4Hz),19.27(s),19.00(s),14.56(s),11.11(s),9.43(t,J=12.0Hz),7.65(s).HRMS(ESI)of compound Z-16:calcd.for C 51 H 89 N3O 17 [M+H] + =1016.6265,found[M+H] + =1016.6269

[0112] Example 17: Preparation of hydroxypyridinone conjugated with azithromycin-like compounds (conjugates Z-17, Z-18)

[0113] Step 1: Azithromycin 2'-O-succinic acid derivative (compound 23)

[0114]

[0115] Under anhydrous and oxygen-free conditions, commercially available azithromycin, succinic anhydride, and DMAP were placed in a flask, and dry DCM was added. The reaction was carried out overnight at room temperature. After purification, compound 23 was obtained as a white solid, yield: 57%. 1 H NMR (400MHz, CDCl3) δ5.10(d,J=4.7Hz,1H),4.80(dd,J=10.5,7.5Hz,1H),4.66(dd,J=9.8,2.4Hz,1H),4.52(d,J=7.4Hz ,1H),4.16(s,1H),4.06–3.97(m,1H),3.61(d,J=5.4Hz,1H),3.52(d,J=7.1Hz,1H),3.32(d,J=5.8Hz,1H),3.05–2.89(m, 1H),2.79(td,J=12.1,4.1Hz,1H),2.68–2.61(m,1H),2.56–2.47(m,1H),2.30(d,J=16.5Hz,1H),2.04–1.82(m,1H),1.79 –1.69(m,1H),1.64–1.51(m,1H),1.46–1.33(m,1H),1.29–1.12(m,3H),1.05–1.02(m,1H),0.85(dd,J=15.8,7.1Hz,1H). 13C NMR(101MHz, CDCl3)δ178.79(s),177.78(s),172.27(s),100.40(s),94.47(s),82.99(s),78.06(s),77.63 (s),74.14(s),73.70(s),73.03(s),70.91(s),70.00(s),67.88(s),65.65(s),63.61(s),62.64(s),49.48( s),44.95(s),42.18(s),40.17(s),36.13(s),34.65(s),32.30(s),31.71(s),31.06(s),27.45(s),26.58( s),21.92(s),21.58(s),21.15(s),18.16(s),16.24(s),14.56(s),11.20(s),8.80(d,J=13.3Hz),7.16(s).

[0116] Step 2: Preparation of hydroxypyridinone conjugated with azithromycin-like compounds (conjugates Z-17 and Z-18)

[0117]

[0118] Preparation of conjugate Z-17:

[0119] Under anhydrous and anaerobic conditions, the azithromycin 2'-O-succinic acid derivative (compound 23) was dissolved in dry DMF. EDCI and Hobt were added under ice bath conditions, and the mixture was stirred for 30 minutes. DMAP and compound 4 were then added, and the reaction proceeded overnight at room temperature. After the reaction was complete, the mixture was extracted with DCM, washed with brine, and the organic phase was dried. The resulting benzyl-protected conjugate precursor, Z-17, was obtained by rotary chromatography. This precursor was dissolved in 10 mL of methanol, and Pd / C₂ was added. After H₂ replacement, the mixture was reacted overnight at room temperature. After the reaction was complete, the mixture was filtered, and the filtrate was dried under rotary chromatography. The residue was purified by slurrying with dichloromethane / methanol to give conjugate Z-17 as a pale yellow solid. Yield: 46%. 1H NMR (400MHz, DMSO-d6)) δ8.46(s,1H),7.95(s,1H),7.42(s,1H),6.12(s,1H),5.97(s,1H),4.84(s,2H),4.74( s,2H),4.46(d,J=37.2Hz,3H),4.18(d,J=22.1Hz,2H),4.07(s,1H),3.69(s,2H),3.58(s,4H),3.23(s,3H),3. 07(s,1H),2.90(d,J=13.5Hz,2H),2.78–2.63(m,6H),2.29(s,6H),2.23(s,3H),2.15(s,2H),1.89(s,2H),1.7 7(s,1H),1.64(s,1H),1.52(s,2H),1.12(d,J=24.3Hz,17H),0.98(d,J=23.1Hz,10H),0.82(d,J=23.2Hz,7H). 13 C NMR (101MHz, DMSO-d6)) δ124.92(d,J=23.4Hz),77.85(s),73.18(d,J=17.1Hz),65.27(s),41.51(d,J=122.4Hz),36.24( s),29.12(s),28.72(s),22.57(s),21.48(s),18.94(s),18.17(s),15.28(s),11.42(s),9.50(s),7.30(s).HRMS(ESI)of compound Z-17:calcd.for C 49 H 84 N4O 16 [M+H] + =985.5955,found[M+H] + =985.5956

[0120] Preparation of conjugate Z-18:

[0121] Using compound 23 and intermediate 12 as starting materials, the same synthetic method as compound Z-17 was employed to obtain conjugate Z-18, a yellow solid. Yield: 47%. 1H NMR (600MHz, DMSO-d6)) δ8.23(s,1H),6.66(s,1H),6.11(s,1H),4.73(d,J=4.0Hz,1H),4.66(d,J=10.1Hz,1H),4.31 (s,2H),3.71(s,2H),3.63(d,J=8.7Hz,2H),3.37(s,2H),3.04(s,6H),2.93–2.89(m,6H),2.76(s,1H),2.67(d,J=10 .8Hz,1H),2.59(s,1H),2.39(d,J=14.4Hz,6H),2.20–2.12(m,9H),1.79(dd,J=36.9,29.0Hz,4H),1.68–1.57(m,1H) ,1.37(d,J=16.8Hz,2H),1.12(s,3H),1.05–0.98(m,23H),0.79(s,3H),0.76(d,J=6.4Hz,3H),0.65(t,J=7.3Hz,3H). 13 C NMR(151MHz,DMSO-d6))δ177.98(s),176.50(s),173.55(s),130.44(s),101.77(s),95.05(s),83.49(s),77.99(s),77 .51(s),76.36(s),75.24(s),74.13(d,J=5.5Hz),73.76(s),73.20(d,J=18.8Hz),49.25(s),49.07(s),46.24(s),45.11 (s),42.01(s),41.83(s),40.98(s),36.43(d,J=34.7Hz),34.75(s),31.77(s),31.55(s),30.19(s),26.40(s),25.56( s),22.05(s),21.36(s),20.63(s),18.54(s),17.58(s),15.08(s),11.23(s),9.25(s),8.90(s),7.89(s).HRMS(ESI)of compoundZ-18:calcd.for C 50 H 86 N4O 16 [M+H] + =999.6112,found[M+H] + =999.6122

[0122] Example 18: Preparation of hydroxypyridinone conjugated with azithromycin-like compounds (conjugates Z-19, Z-20)

[0123] Step 1: Azithromycin 2'-O-acetyl-4”-O-succinic acid derivative (compound 24)

[0124]

[0125] Commercially available azithromycin was dissolved in dry DCM, and acetic anhydride and triethylamine were added. The mixture was stirred at room temperature for 24 hours. After the reaction was complete, the reaction was quenched with 5% NaHCO3 aqueous solution. The aqueous layer was extracted with DCM, washed with water, dried, and concentrated. The residue was crystallized from acetone:water (2:1) into a white solid, which was the azithromycin 2'-O-acetyl derivative. The azithromycin 2'-O-acetyl derivative, succinic anhydride, and DMAP were placed in a flask, and dry DCM was added. The mixture was reacted overnight at room temperature. After purification, compound 24 was obtained as a white solid, with a yield of 57%.

[0126] Step 2: Preparation of hydroxypyridinone conjugated with azithromycin-like compounds (conjugates Z-19 and Z-20)

[0127]

[0128] Preparation of conjugate Z-19:

[0129] Under anhydrous and anaerobic conditions, the azithromycin 2'-O-acetyl-4'-O-succinic acid derivative (compound 24) was dissolved in dry DMF. EDCI and Hobt were added under ice bath conditions, and the mixture was stirred for 30 minutes. DMAP and compound 4 were then added, and the reaction proceeded overnight at room temperature. After the reaction was complete, the mixture was extracted with DCM, washed with brine, and the organic phase was dried. The resulting benzyl-protected conjugate precursor, Z-19, was obtained by rotary chromatography. This precursor was dissolved in 10 mL of methanol, and Pd / C₂ was added. After H₂ replacement, the mixture was reacted overnight at room temperature. After the reaction was complete, the mixture was filtered, and the filtrate was dried under rotary chromatography. The residue was purified by slurrying with dichloromethane / methanol to give conjugate Z-19 as a pale yellow solid. Yield: 43%. 1H NMR(600MHz,DMSO-d6)δ8.56(d,J=35.9Hz,1H),8.12(s,1H),7.43(s,1H),6.73(s,1H),6.17(s,1H),4.88–4.69(m,2H),4.44(t,J=32.7Hz,2H),4.05(d,J=11.5Hz,6H),3.70(d,J=18.2Hz,2H),3.59(s,2H),3.46(d,J=17.7Hz,2H),3.22(s,3H),3.18(s,1H),3.01(s,3H),2.95–2.86(m,3H),2.71(d,J=44.5Hz,2H),2.54(s,3H),2.45–2.29(m,7H),2.25(d,J=13.8Hz,2H),2.02(s,1H),1.97–1.86(m,3H),1.79(d,J=38.7Hz,3H),1.50(s,1H),1.36(s,1H),1.27(s,1H),1.20(s,2H),1.16–1.01(m,19H),0.93(s,3H),0.86(s,3H),0.78(s,3H). 13 CNMR(151MHz,DMSO-d6)δ177.94(s),177.66(s),172.09(s),171.92(s),170.92(s),147.27(s),145.62(s),125.28(s),107.25(s),102.04(s),94.92(s),83.50(s),77.79(d,J=13.1Hz),76.49(s),74.64(s),74.13(s),73.54(s),73.27(s),73.13(s),69.93(s),66.91(s),65.33(d,J=7.3Hz),63.11(s),49.27(s),45.90(s),45.18(s),42.05(s),40.44(s),36.38(s),34.98(s),30.59(s),28.68(s),27.16(s),26.08(s),22.43(s),21.63(s),21.53(d,J=22.9Hz),18.81(s),18.62(s),17.99(s),15.22(s),11.39(s),9.40(s),7.69(s).HRMS(ESI)of compound Z-19:calcd.for C 49 H 84 N4O 16 [M+H]+ =985.5955,found[M+H] + =985.5948

[0130] Preparation of conjugate Z-20:

[0131] Using compound 24 and intermediate 12 as starting materials, the same synthetic method as compound Z-20 was employed to obtain conjugate Z-20, a pale yellow solid. Yield: 45%. 1 H NMR (600MHz, DMSO-d6) δ8.14(d,J=17.1Hz,1H),7.34(d,J=29.1Hz,3H),6.74(s,2H),6.20(d,J=8.7Hz,1H),5.18–5. 07(m,2H),4.75–4.68(m,1H),4.41–4.35(m,2H),3.87(s,6H),3.44–3.41(m,3H),3.26–3.14(m,4H),3.03(s,5H),2.9 8–2.89(m,2H),2.63–2.53(m,3H),2.46–2.31(m,4H),2.28(d,J=6.8Hz,4H),2.07–1.92(m,3H),1.90(s,1H),1.84–1. 75(m,2H),1.63–1.39(m,4H),1.35–1.29(m,2H),1.26–0.99(m,21H),0.98–0.83(m,6H),0.79(dd,J=9.0,5.2Hz,3H). 13C NMR (151MHz, DMSO-d6) δ177.84 (s), 172.63 (d, J = 18.8Hz), 171.66 (s), 155.5 4(s),148.38(s),148.06(s),146.72(s),146.16(s),146.01(d,J=42.9Hz),1 40.89(s),138.26(d,J=24.0Hz),138.15(s),131.92(s),129.82(s),129.20 (s),128.89(s),128.71(s),118.02(d,J=19.4Hz),77.84(s),74.71(s),74.0 9(s),73.15(s),72.75(d,J=12.4Hz),71.52(s),70.04(s),67.64(s),65.40 (s),64.95(s),58.00(s),49.26(s),36.75(s),36.22(s),35.22(s),34.79(s) ),31.76(s),30.38(s),29.50(s),28.53(s),21.54(d,J=38.9Hz),20.67(d,J =18.6Hz),19.67(s),18.65(s),13.96(s),11.66(s),10.30(s).HRMS(ESI)of compound Z-20:calcd.for C 50 H 86 N4O 16 [M+H] + =999.6112,found[M+H] + =999.6117.

[0132] Example 19: Preparation of pyridone intermediates 1-17

[0133] Preparation of intermediate 1:

[0134] Kojic acid (4.38 g, 30.82 mmol) was dissolved in methanol (25 mL), and NaOH (1.36 g, 33.90 mmol) was added. Then, benzyl chloride (4.29 g, 33.90 mmol) was added dropwise. The reaction was completed after reflux for 12 hours. The reaction solution was concentrated under reduced pressure, and the residue was dissolved in water and then extracted three times with dichloromethane. The residue was washed with 5% NaOH aqueous solution and saturated brine to collect the organic phase. The mixed organic layer was dried over anhydrous sodium sulfate, concentrated under vacuum, and the crude product was recrystallized in dichloromethane / petroleum ether to give intermediate 1. Yield: 80%. 1H NMR (400MHz, DMSO-d6) δ8.18(s,1H),7.35-7.44(m,5H),6.35(s,1H),5.71(s,1H),4.95(s,2H),4.30(s,2H). 13 C NMR(101MHz,DMSO-d6)δ173.71,168.54,147.10,141.68,136.64,128.91,128.65,128.59,111.65,71.05,59.81.MS(ESI) of compound 1:calcd.forC 13 H 12 O4[M+H] + =233.1,found[M+H] + 233.5.

[0135] Preparation of intermediate 2:

[0136] Methylamine (40 mL) was added to a methanol (40 mL) solution of 1 (10.00 g, 43.06 mmol). The reaction mixture was then stirred and reacted at 25 °C for 12 h. The solvent was removed under high vacuum, and the crude product was recrystallized from methanol to give solid 2. Yield: 74%. 1 HNMR(400MHz,DMSO-d6)δ7.57(s,1H),7.33-43(m,5H),6.24(s,1H),5.57(s,1H),5.00(s,2H),4.37(s,2H),3.59(s,3H). 13 C NMR(101MHz,DMSO-d6)δ172.07,149.19,147.45,137.68,129.70,128.78,128.44,128.30,115.50,71.05,59.73,39.70.MS(ESI) of compound 2:calcd.for C 14 H 15 NO3[M+H] + =246.1, found[M+H] + 246.4.

[0137] Preparation of intermediate 3:

[0138] Compound 2 (9.00 g, 36.69 mmol), phthalimide (6.48 g, 44.03 mmol), and triphenylphosphine (11.55 g, 44.03 mmol) were placed in a dry 250 mL double-necked flask and reacted under nitrogen protection. Then, 100 mL of anhydrous tetrahydrofuran was added, and the reaction mixture was placed in an ice-water mixture and allowed to stand for 30 minutes. Diethylbutyrite (7.67 g, 44.03 mmol) was then added dropwise. After completion, the temperature was slowly raised to 25 °C. The mixture was stirred overnight at 25 °C, and a large amount of precipitate formed in the reaction solution. The precipitate was filtered, and the filter cake was washed with cold tetrahydrofuran to give a yellow solid 3. Yield: 82%. 1 H NMR (400MHz, DMSO-d6) δ7.89-7.96(m,4H),7.65(s,1H),7.32-7.42(m,5H),5.91(s,1H),4.98(s,2H),4.77(s,2H),3.75(s,3H). 13 C NMR (101MHz, DMSO-d6) δ171.54,167.87,147.68,144.10,137.52,135.25,131. 97,129.72,128.80,128.43,128.35,123.93,114.49,71.02,37.72.MS(ESI)of compound 3:calcd.for C 22 H 18 N₂O₂[M+H] + =375.1, found[M+H] + 375.6.

[0139] Preparation of intermediate 4:

[0140] Compound 3 (10.00 g, 26.71 mmol) was dissolved in ethanol (100 mL), followed by the addition of 22 mL of 5.5% hydrazine hydrate solution. The mixture was heated under reflux for 3 h. The reaction mixture was then concentrated under reduced pressure, and 50 mL of water was added to the residue, followed by the addition of 10 mol / L sodium hydroxide solution to adjust the pH to 12. The mixture was extracted three times with dichloromethane, dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated. The residue was purified by column chromatography (DCM:MeOH = 10:1) to give a white solid 4. Yield: 88%. 1 H NMR (400MHz, DMSO-d6) δ7.62(s,1H),7.32-7.43(m,5H),6.30(s,1H),5.00(s,2H),3.79(s,2H),3.62(s,3H). 13C NMR(101MHz,DMSO-d6)δ171.84,149.25,147.45,137.59,129.70,128.79,128.43,128.33,115.87,115.44,71.01,59.69.MS(ESI)ofcompound 4:calcd.for C 14 H 16 N₂O₂[M+H] + =245.1,found[M+H] + 245.6.

[0141] Preparation of intermediate 5:

[0142] Compound 3 (0.3 g, 1.23 mmol) was dissolved in anhydrous DCM, and succinic anhydride (0.160 g, 1.6 mmol) and DMAP (0.165 g, 1.35 mmol) were added. The mixture was stirred overnight at room temperature. After the reaction was complete, a large amount of precipitate was formed in the reaction solution. The precipitate was filtered and dried to give a white solid, 5. Yield: 84%. 1 H NMR (400MHz, DMSO-d6) δ8.43(s,1H),7.61(s,1H),7.37(dt,J=15.2,6.8Hz,5H),6.13(s,1H) ,4.99(s,2H),4.21(d,J=4.8Hz,2H),3.59(s,3H),2.22(t,J=6.8Hz,4H),1.82–1.67(m,2H). 13 C NMR(101MHz,DMSO-d6)δ174.91(s),174.36(s),171.83(d,J=2.7Hz),148.27(s),147.50(s),146.79(s),137.59(s),12 9.62(s),128.79(s),128.37(d,J=9.2Hz),115.69(s),107.18(s),71.03(s),31.00(s),30.40(s),29.57(s).MS(ESI)of compound 5:calcd.for C 18 H 20 N₂O₅[M+H] + =345.1,found[M+H] + 345.4.

[0143] Preparation of intermediate 6:

[0144] Compound 3 (1 g, 4 mmol) was dissolved in anhydrous DCM, and glutaric anhydride (0.685 g, 6 mmol) and DMAP (0.538 g, 4.4 mmol) were added. The mixture was stirred overnight at room temperature. After the reaction was complete, a large amount of precipitate formed in the reaction solution. The precipitate was filtered and dried to give a white solid, 6. Yield: 81%. 1 H NMR (400MHz, DMSO-d6) δ8.43(s,1H),7.61(s,1H),7.37(dt,J=15.2,6.8Hz,5H),6.13(s,1H) ,4.99(s,2H),4.21(d,J=4.8Hz,2H),3.59(s,3H),2.22(t,J=6.8Hz,4H),1.82–1.67(m,2H). 13 C NMR(101MHz,DMSO-d6)δ174.67(s),172.44(s),171.80(s),147.50(s),146.92(s),137.53(s),129.55 (s),128.79(s),128.37(d,J=7.6Hz),115.40(s),71.04(s),34.72(s),33.63(s),21.13(s).MS(ESI)of compound 4:calcd.for C 19 H 22 N₂O₅[M+H] + =359.2, found[M+H] + 359.6.

[0145] Preparation of intermediate 7:

[0146] Kojic acid (20.0 g, 140.74 mmol) was dissolved in SOCl2 (48.0 mL) and stirred at room temperature for 1.5 h. After the reaction was complete, petroleum ether was added to the mixture, and the mixture was stirred continuously for 30 min. The precipitate was collected by filtration, washed with petroleum ether, and dried to obtain a yellow solid. The yellow solid was added to 150 mL of water and heated to 50 °C. Then, zinc powder (36.53 g, 562 mmol) was added in portions, and concentrated hydrochloric acid (110 mL) was added slowly while maintaining the temperature below 80 °C. The final reaction was carried out at 70 °C for 3 hours. After the reaction was complete, the mixture was extracted with dichloromethane, dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure to obtain a crude product. The crude product was recrystallized to obtain red needle-like crystals. Yield: 86%. 1H NMR(400MHz,DMSO-d6)δ8.95(s,1H),7.96(s,1H),6.23(s,1H),2.23(s,3H).13C NMR(101MHz,DMSO-d6)δ19.6,112.5,139.8,145.8,165.7,174.3.MS(ESI)of compound 7:calcd.for C6H6O3[M+H] + =127.0,found[M+H] + 127.4.

[0147] Preparation of intermediate 8:

[0148] Compound 7 (3.00 g, 23.79 mmol) was dissolved in water (20 mL), and NaOH (1.05 g, 26.2 mmol) was added. Then, 37% formaldehyde aqueous solution (2 mL) was added gradually, and the mixture was stirred overnight at 25 °C. After the reaction was complete, the pH was adjusted to 1 with concentrated HCl, and the mixture was cooled to 0 °C. A large amount of precipitate was produced; this was filtered and dried to give intermediate 8 as a white solid. Yield: 89%. 1 H NMR (400MHz, DMSO-d6) δ8.86 (s, 1H), 6.22 (s, 1H), 5.36 (s, 1H), 4.39 (d, J = 9.8Hz, 2H), 2.26 (s, 3H). 13 CNMR(101MHz,DMSO-d6)δ174.36,165.08,149.89,141.74,111.62,55.45,19.76.MS(ESI)ofcompound8:calcd.for C7H8NO4[M+H] + =157.0,found[M+H] + 157.2.

[0149] Preparation of intermediate 9:

[0150] Compound 8 (2.90 g, 18.57 mmol) was dissolved in methanol (30 mL), sodium hydroxide (0.82 g, 20.43 mmol) was added, followed by dropwise addition of benzyl bromide (3.49 g, 20.43 mmol). The mixture was refluxed for 12 hours, then concentrated under reduced pressure. The residue was dissolved in water and extracted three times with dichloromethane, followed by washing twice each with 5% sodium hydroxide aqueous solution and saturated brine. The organic phase was collected. The combined organic layers were dried over anhydrous sodium sulfate, concentrated under reduced pressure, and the crude product was recrystallized from dichloromethane to give compound 9 as a solid. Yield: 88%. 1H NMR (400MHz, DMSO-d6) δ7.33-7.35(m,5H),6.15(s,1H),5.13(s,2H),4.30(s,2H),2.21(s,3H). 13 C NMR (101MHz, CDCl3) δ176.32,165.05,158.78,142.06,136.47,129.25,128.65,114.81,73.90,57.30,19.64.MS(ESI) of compound 9:calcd.forC 14 H 14 O4[M+H] + =247.1, found[M+H] + 247.4.

[0151] Preparation of intermediate 10:

[0152] Compound 9 (5.00 g, 20.30 mol) was dissolved in anhydrous dichloromethane (25 mL), followed by the addition of 3,4-dihydropyran (3.42 g, 40.60 mol) and a small amount of p-toluenesulfonic acid as a catalyst. The mixture was reacted at 25 °C for 2 h. The reaction solution was then washed twice with 5% sodium carbonate aqueous solution, followed by two washes with water, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to give a yellow oil. The yellow oil was dissolved in ethanol (15 mL) and methylamine (15 mL). The reaction mixture was sealed in a thick-walled glass tube and stirred at 70 °C for 24 h. Next, the mixture was concentrated under vacuum to give a brown liquid. The brown liquid was dissolved in ethanol (20 mL), and refluxed for 4 h with 2N hydrochloric acid (25 mL). The solvent was concentrated under vacuum, 20 mL of water was added, and the aqueous phase was adjusted to pH 9 with 10N sodium hydroxide solution, followed by extraction three times with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure to give a crude product. This product was recrystallized in a methanol / ethylene glycol-dioxane mixed solvent to give a white solid, 10. Yield: 67%. 1 H NMR (400MHz, DMSO-d6) δ7.34-7.46(m,5H),6.17(s,1H),5.43-5.45(m,1H),5.03(s,2H),4.55(d,J=5.4Hz,2H),3.60(s,3H),2.29(s,3H). 13C NMR(101MHz,DMSO-d6)δ172.78,148.31,145.14,143.26,138.25,128.72,128.67,128.23,117.77,73.12,54.32,35.92,20.41.MS(ESI)of compound10:calcd.for C 15 H 17 NO3[M+H] + =260.1,found[M+H] + 260.9.

[0153] Preparation of intermediate 11:

[0154] Compound 10 (3.90 g, 15.04 mmol), phthalimide (2.66 g, 18.05 mmol), and triphenylphosphine (4.73 g, 18.05 mmol) were placed in a dry 50 mL double-necked flask and treated under nitrogen protection. Next, 20 mL of anhydrous tetrahydrofuran was added, and the reaction mixture was placed in an ice-water mixture at 0 °C and allowed to stand for 30 min. Then, diethylbutyrite (3.14 g, 18.05 mmol) was added dropwise. After the addition was complete, the temperature was slowly raised to 25 °C. The mixture was stirred overnight at 25 °C, and a large amount of precipitate formed in the reaction solution. The precipitate was filtered, and the filter cake was washed with cold tetrahydrofuran to obtain compound 10 as a white solid. Yield: 83%. 1 H NMR (400MHz, DMSO-d6) δ7.84(s,4H),7.40-7.42(m,2H),7.25-7.31(m,3H),6.20(s,1H),5.21(s,2H),4.93(s,2H),3.53(s,3H),2.28(s,3H). 13 C NMR(101MHz,DMSO-d6)δ172.27,167.95,148.04,146.62,138.26,134.97,131.98 ,128.79,128.50,128.08,123.60,118.17,71.51,36.74,34.95,20.69.MS(ESI)of compound 11:calcd.for C 23 H 20 N₂O₄[M+H] + =389.1, found[M+H] + 389.4.

[0155] Preparation of intermediate 12:

[0156] Compound 11 (4.8 g, 12.36 mmol) was dissolved in ethanol (50 mL), and 10 mL of 5.5% hydrazine hydrate solution was added. The mixture was then heated under reflux for 3 h. The reaction mixture was then concentrated under reduced pressure. 30 mL of water was added to the residue, followed by the addition of 10 mol / L sodium hydroxide solution to adjust the pH to 12. The mixture was extracted three times with dichloromethane, dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure. The residue was purified by column chromatography (dichloromethane:methanol = 10:1) to give a white solid, 12. Yield: 78%. 1 H NMR (300MHz, DMSO-d6) δ7.32-7.44(m,5H),6.14(s,1H),5.08(s,2H),3.73(s,2H),3.59(s,3H),2.28(s,3H). 13 C NMR(75MHz,DMSO-d6)δ172.64,147.91,145.31,144.50,138.32,129.00,128.72,128.30,117.61,72.58,36.91,35,60,20.57.MS(ESI) of compound 12:calcd.for C 15 H 18 N₂O₂[M+H] + =259.1,found[M+H] + 259.6.

[0157] Preparation of intermediate 13:

[0158] Compound 12 (0.400 g, 1.55 mmol) was dissolved in anhydrous DCM, and succinic anhydride (0.233 g, 2.33 mmol) and DMAP (0.208 g, 1.7 mmol) were added. The mixture was stirred overnight at room temperature. After the reaction was complete, a large amount of precipitate formed in the reaction solution. The precipitate was filtered and dried to give a white solid, 13. Yield: 74%. 1 H NMR(400MHz,DMSO-d6)δ8.19(t,J=4.9Hz,1H),7.48–7.25(m,5H),6.22(s,1H),5 .08(s,2H),4.39(d,J=4.9Hz,2H),3.43(s,3H),2.47–2.31(m,4H),2.27(s,3H). 13C NMR(101MHz,DMSO-d6)δ174.61(s),174.40(s),172.56(s),171.63(s),148.42(s),146.15(s),141.02(s),138.15(s),128.81(d,J =18.1Hz),128.32(s),117.88(s),107.20(s),72.83(s),36.20(s),34.80(s),30.31(d,J=10.7Hz),29.63(s),20.59(s).MS(ESI)of compound 13:calcd.for C 19 H 22 N₂O₅[M+H] + =359.2, found[M+H] + 359.6.

[0159] Preparation of intermediate 14:

[0160] Compound 12 (0.4 g, 1.55 mmol) was dissolved in anhydrous DCM, and glutaric anhydride (0.266 g, 2.33 mmol) and DMAP (0.208 g, 1.7 mmol) were added. The mixture was stirred overnight at room temperature. After the reaction was complete, a large amount of precipitate formed in the reaction solution. The precipitate was filtered and dried to give a white solid, 14. Yield: 78%. 1 H NMR (400MHz, DMSO-d6) δ8.43(s,1H),7.61(s,1H),7.37(dt,J=15.2,6.8Hz,5H),6.13(s,1H) ,4.99(s,2H),4.21(d,J=4.8Hz,2H),3.59(s,3H),2.22(t,J=6.8Hz,4H),1.82–1.67(m,2H). 13 C NMR(101MHz,DMSO-d6)δ174.75(s),172.55(s),172.24(s),148.42(s),146.14(s),140.97(s),138.16(s),128.84(s),128.31(s),128. 06(s),117.89(s),107.17(s),72.78(s),36.21(s),34.75(d,J=17.2Hz),33.66(d,J=15.6Hz),21.18(s),20.61(d,J=7.4Hz).MS(ESI)of compound 14:calcd.for C 20 H 24 N₂O₅[M+H] +=373.3, found[M+H] + 373.6.

[0161] Preparation of intermediate 15:

[0162] Compound 1 (1.20 g, 5.17 mmol) was dissolved in ethanol (10 mL) and water (10 mL), followed by the addition of hydroxylamine chloride (2.62 g, 37.74 mmol), and then sodium acetate trihydrate (5.14 g, 37.74 mmol). The reaction mixture was heated at 60 °C overnight. The mixture was cooled to room temperature, and then the ethanol was removed under vacuum. The resulting solid 15 (0.79 g, 3.20 mmol) was collected by filtration and washed with water (20 mL). Yield: 62%. 1 H NMR (400MHz, DMSO-d6) δ7.98(s,1H),7.34-7.44(m,6H),6.87(s,1H),5.11(s,2H),4.47(s,2H). 13 C NMR(101MHz,DMSO-d6)δ146.05,144.30,136.67,128.90,128.55,128.36,127.42,109.35,71.25,58.22.MS(ESI)ofcompound 15:calcd.for C 13 H 13 NO4[M+H] + =248.1, found[M+H] + 248.4.

[0163] Preparation of intermediate 16:

[0164] Compound 16 (5.80 g, 23.46 mol) was dissolved in dimethyl sulfoxide (50 mL), followed by the addition of potassium carbonate (3.89 g, 28.15 mol) and fractionally by benzyl bromide (4.81 g, 28.15 mol). The reaction mixture was stirred at 25 °C for 3 h. The mixture was diluted with water and extracted with dichloromethane. The combined organic extracts were washed with water. The solvent was then removed under high vacuum, and the crude product was recrystallized from methanol to give solid 16. Yield: 81%. 1 H NMR(400MHz,DMSO-d6)δ8.01(s,1H),7.49-7.51(m,2H),7.34-7.45(m,8H),6.15 (s,1H),5.62(t,J=6.0Hz,1H),5.24(s,2H),5.01(s,2H),4.40(d,J=5.9Hz,2H). 13C NMR(101MHz,DMSO-d6)δ171.38,148.05,147.00,137.17,133.63,130.62,129.92 ,129.12,128.86,128.55,128.47,111.45,80.61,71.07,57.30,40.92.MS(ESI)of compound 16:calcd.for C 20 H 19 NO4[M+H] + =338.1, found[M+H] + 338.6.

[0165] Preparation of intermediate 17:

[0166] Compound 17 (6.40 g, 13.72 mol) was dissolved in ethanol (100 mL), followed by the addition of 90 mL of 5.5% hydrazine hydrate solution. The mixture was heated under reflux for 3 h. The reaction mixture was then concentrated under reduced pressure. 25 mL of water was added to the residue, followed by the addition of 10 mol / L sodium hydroxide solution to adjust the pH to 12. The mixture was extracted three times with dichloromethane, dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure. The crude product was recrystallized from ethyl acetate to give solid 17. Yield: 72%. 1 H NMR (400MHz, CDCl3) δ7.32-7.42(m,8H),7.20-7.22(m,2H),7.01(s,1H),6.30(s,1H),5.03(s,2H),4.98(s,2H),3.60(s,2H). 13 C NMR (101MHz, CDCl3) δ172.76,148.45,146.70,136.25,132.31,130.07,129.95,1 29.14,128.64,128.24,127.86,123.46,112.55,81.38,71.68,40.95.MS(ESI)of compound 17:calcd.for C 20 H 20 N₂O₃[M+H] + =337.1, found[M+H] + 337.6.

[0167] Example 20: Inhibitory activity of pyridone-erythromycin conjugate against Gram-positive and Gram-negative bacteria

[0168] Experimental Methods: This experiment used the micro-broth serial dilution method to determine the minimum inhibitory concentration (MIC) of the conjugates against bacteria. The maximum screening concentration of the compound was 200 μM. The conjugates were diluted into a series of concentration gradients using a two-fold dilution method. 100 μL of drug-containing culture medium was added to each well of a 96-well plate, followed by 100 μL of bacterial suspension. After incubation at 37℃ for 18-20 h, the absorbance was measured at 600 nm using a microplate reader. The experiment was repeated three times to screen out conjugates with antibacterial activity. The experimental results are shown in Tables 1 and 2.

[0169] Table 1. Minimum inhibitory concentrations (μM) of erythromycin-hydroxypyridinone conjugates against common Gram-positive bacteria.

[0170]

[0171] Note: ERY stands for erythromycin, and AZM stands for azithromycin.

[0172] Table 2. Minimum inhibitory concentrations (μM) of erythromycin-hydroxypyridinone conjugates against common Gram-negative bacteria.

[0173]

[0174] Note: ERY stands for erythromycin, and AZM stands for azithromycin.

[0175] Experimental Results: Table 1 shows that the inhibitory activity of the compounds against Gram-positive bacteria decreases with increasing aliphatic chain length. The compound with four atoms between the two chains exhibits the best antibacterial activity, which may be related to the solubility of the compounds due to carbon chain length. Furthermore, the best antibacterial activity is observed when the coupling site is at the C-6 position of the hydroxypyridinone; changing the coupling site to the C-2 or N-1 position results in varying degrees of decrease in antibacterial activity.

[0176] As shown in Table 2, the experimental results demonstrate that by conjugating hydroxypyridinone with erythromycin derivatives, and screening a series of compounds against different phenotypic strains and clinically resistant strains of Gram-negative bacteria such as *Escherichia coli* (E. coli), *Klebsiella pneumoniae* (K. pneumoniae), and *Pseudomonas aeruginosa* (PA), this conjugation method successfully extended the antibacterial spectrum of erythromycin derivatives to Gram-negative bacteria, particularly showing a 2-4 fold increase in activity against P. aeruginosa; and also exhibiting varying degrees of inhibitory activity against clinically resistant strains of P. aeruginosa. The most active conjugate was Z-5, with a MIC between 25-100 μM.

[0177] Example 21: Anti-biofilm activity of pyridone-erythromycin conjugate (Z-5) against Pseudomonas aeruginosa

[0178] Experimental Results: We further investigated the antibiotic membrane activity of the best-performing conjugate Z-5 and erythromycin against the standard P. aeruginosa strain PAO1 and the drug-resistant strain PA14. The results are as follows: Figure 1 As shown, compared to the parent compound erythromycin, the conjugate exhibited a 70% inhibition rate against *Pseudomonas aeruginosa* PAO, while erythromycin only showed a biofilm inhibition rate of approximately 40%. We further tested the antibiofilm activity of the conjugate and the parent compound against drug-resistant *Pseudomonas aeruginosa* strain PA14. The conjugate Z-5 still showed over 60% antibiofilm activity, while the erythromycin group only showed a 35% biofilm inhibition rate.

[0179] In summary, this conjugation method not only successfully extends the antibacterial spectrum of erythromycin derivatives to negative bacteria, especially Pseudomonas aeruginosa, but also exhibits varying degrees of inhibitory activity against clinically resistant strains; it also significantly enhances the anti-biofilm activity of erythromycin derivatives against Pseudomonas aeruginosa.

[0180] Example 22: Inhibitory activity of pyridone-azithromycin conjugate against Gram-positive and Gram-negative bacteria

[0181] Experimental Methods: This experiment used the micro-broth serial dilution method to determine the minimum inhibitory concentration (MIC) of the conjugate against bacteria. The maximum screening concentration of the compound was 200 μM, and the conjugate was diluted into a series of concentration gradients using the two-fold dilution method. The experimental results are shown in Tables 3 and 4.

[0182] Table 3. Minimum inhibitory concentrations (μM) of azithromycin-hydroxypyridinone conjugates against common Gram-positive bacteria.

[0183]

[0184] Note: AZM stands for azithromycin.

[0185] Table 4. Minimum inhibitory concentrations (μM) of azithromycin-hydroxypyridinone conjugates against common Gram-negative bacteria.

[0186]

[0187]

[0188] Note: AZM stands for azithromycin.

[0189] Example 23: Anti-biofilm activity of pyridone-azithromycin conjugate against Pseudomonas aeruginosa

[0190] Experimental Results: We further investigated the antibiotic membrane activity of the best-performing conjugate and azithromycin against Pseudomonas aeruginosa PAO1, and the results are as follows: Figure 2As shown, at sub-inhibitory concentrations, the pyridone-azithromycin conjugate exhibited certain anti-biofilm activity against Pseudomonas aeruginosa, which was concentration-dependent. The anti-biofilm activity of the obtained compound was comparable to that of azithromycin.

[0191] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A hydroxypyridinone-coupled macrolide compound of formula (I) or (II) or a pharmaceutically acceptable salt, isomer, solvate or prodrug thereof: in, One of R is The other is hydrogen; X is selected from -NHCO- and -O-; Y is selected from -NH(CH2) p -or-(CH2) p -; Z is selected from -(CH2) q -; R1 is selected from methyl, ethyl, propyl, butyl, hydroxyl, or a linking bond with -XCH2-; R2 is selected from hydrogen, methyl, ethyl, propyl, butyl, hydroxy, hydroxymethyl, and hydroxyethyl. n is selected from 2, 3, 4, 5, 6, 7, or 8; m is selected from 0, 1, 2, or 3; p is selected from 2, 3, 4, 5, 6, 7, or 8; q is selected from 0, 1, 2, 3 or 4.

2. The hydroxypyridinone-coupled macrolide compound or its pharmaceutically acceptable salt, isomer, solvate or prodrug according to claim 1, characterized in that, X passes through -CO- and -(CH2) n -connect.

3. The hydroxypyridinone-coupled macrolide compound or its pharmaceutically acceptable salt, isomer, solvate or prodrug according to claim 1, characterized in that, The compound is selected from:

4. A method for preparing a hydroxypyridinone-coupled macrolide compound according to claim 1, characterized in that... Includes the following steps: (1.1) Synthesis of hydroxypyridinone iron support: A series of intermediate compounds 1-17 were synthesized from kojic acid as raw material; (1.2) Synthesis of erythromycin derivatives: Erythromycin and hydrazine hydrate were refluxed in methanol; the solvent was evaporated under reduced pressure, the residue was dissolved in a solution of isopropanol and water, refluxed, stirred until cooled, filtered after an ice bath, and the white precipitate was obtained as erythromycin hydrazine derivative 18. Starting with erythromycin, the carbonyl group at the C-9 position of erythromycin reacts with hydroxylamine hydrochloride in pyridine solution, and after purification, erythromycin oxime derivative 19 is obtained; (1.3) Erythromycin hydrazine derivative 18 and compounds 5, 6, 13 or 14 were subjected to amide condensation in EDCI, Hobt, DMAP or DMF, and a series of intermediates were obtained after purification. Erythromycin oxime derivative 19 and 1,4-dibromobutane or 1,6-dibromohexane or 1,8-dibromooctane were refluxed in K2CO3 and acetone, and purified to obtain compounds 20-22; compounds 20-22 and compounds 2 or 10-12 were reacted in NaH and DMF, and purified to obtain a series of intermediates; (1.4) Synthesis of erythromycin-hydroxypyridinone conjugates: The intermediate from step 1.3 was treated overnight in methanol with H2 and 10% Pd / C, and after purification, conjugates Z-1, Z-2, Z-3, Z-4, Z-5, Z-6, Z-7, Z-8, Z-9, Z-10, Z-11, Z-12, Z-13, Z-14, Z-15, and Z-16 were obtained; The synthesis circuit is as follows: (1.5) Synthesis of azithromycin derivatives: Azithromycin and 2'-O-acetylazithromycin derivatives were reacted with succinic anhydride in dry DCM, and DMAP was added. After purification, azithromycin carboxylic acid derivatives 23 and 24 were obtained. (1.6) Synthesis of azithromycin-hydroxypyridinone intermediate: The above carboxylic acid derivatives 23 and 24 and hydroxypyridinone derivatives 4 and 12 were acylated in EDCI, Hobt and DMF, and the intermediate was obtained after further purification; (1.7) Synthesis of azithromycin-hydroxypyridinone conjugates: The intermediates of step 1.6 were treated overnight in methanol with H2 and 10% Pd / C, and after purification, conjugates Z-17, Z-18, Z-19 and Z-20 were obtained. The synthesis circuit is as follows:

5. The use of the hydroxypyridinone-coupled macrolide compound or its pharmaceutically acceptable salt, isomer, solvate or prodrug according to any one of claims 1-3 in the preparation of antibacterial agents and antibiofilm agents.

6. The application according to claim 5, characterized in that, The bacteria include Gram-positive bacteria and Gram-negative bacteria.

7. The application according to claim 6, characterized in that, The Gram-positive bacteria include Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Bacillus subtilis, and Staphylococcus epidermidis; the Gram-negative bacteria include Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, and Proteus vulgaris.

8. A pharmaceutical composition comprising at least one of the following: a hydroxypyridinone coupled with a macrolide compound as described in any one of claims 1-3, or a pharmaceutically acceptable salt, isomer, solvate, or prodrug thereof.

9. The pharmaceutical composition according to claim 8, characterized in that, The pharmaceutical composition further comprises one or more pharmaceutically acceptable carriers or excipients.

Images