Neuraminidase inhibitor based on hydrophobic label technology, and preparation method, derivative, pharmaceutical composition and application thereof

Abstract

The invention discloses a neuraminidase inhibitor based on a hydrophobic label technology, and a preparation method, a derivative, a pharmaceutical composition and application thereof. The structure of the neuraminidase inhibitor is shown as a formula (I). The neuraminidase inhibitor based on the hydrophobic tag technology has enhanced antiviral activity and effective oseltamivir drug resistance reversal activity, and a new drug is provided for treatment of influenza virus infection, especially oseltamivir drug resistance virus infection diseases.

Description

Technical Field

[0001] The present application relates to the technical field of pharmaceutical applications, and particularly to a neuraminidase inhibitor based on hydrophobic tag technology, its preparation method, derivatives, pharmaceutical compositions and applications. Background Art

[0002] Influenza virus is a single-stranded negative-sense RNA virus, which can be divided into four types: A, B, C, and D according to the different characteristics of its antigen genes. The frequent outbreaks of influenza virus infections pose a serious threat to the lives and health of humans and animals. Currently, there are mainly three types of antiviral drugs used for the treatment and prevention of influenza: M2 ion channel blockers, neuraminidase inhibitors (NAIs), and cap-dependent endonuclease inhibitor baloxavir marboxil. Due to widespread drug resistance, M2 ion channel blockers are no longer clinically used. Cap-dependent endonuclease inhibitors are prone to drug resistance and face significant treatment limitations, which may weaken their long-term clinical applications. NAIs (including oseltamivir, zanamivir, peramivir, and laninamivir, etc.) are still the most effective antiviral drugs at present because of their potent efficacy, better safety and lower side effects. However, the widespread use of oseltamivir has led to the emergence of drug-resistant virus strains, mainly caused by mutations such as H274Y (H1N1 and H5N1), N294S (H7N9), and R292K (H3N2). The emergence of drug-resistant virus strains has led to an increase in the treatment failure rate and the risk of community transmission, further increasing the difficulty of public health prevention and control. Therefore, it is still crucial to develop new antiviral drugs to combat influenza drug resistance. Summary of the Invention

[0003] To overcome the deficiencies of the prior art and effectively solve the problem of influenza virus drug resistance, the present application provides a neuraminidase inhibitor based on hydrophobic tag technology, its preparation method, derivatives, pharmaceutical compositions and applications. The present application adopts the following technical solutions:

[0004] The first aspect of the present application discloses a neuraminidase inhibitor based on hydrophobic tag technology, the structure of which is shown in formula (Ⅰ):

[0005]

[0006] Linker is selected from the following structures: n is a natural number between 2 and 10, m is 0 or 1, k is a natural number between 0 and 10, h is a natural number between 0 and 10, and s is a natural number between 1 and 5;

[0007] HyT is selected from the following structures: For example, n can be 2, 3, 4, 5, 6, 7, 8, 9, or 10, k can be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, h can be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, and s can be 1, 2, 3, 4, or 5.

[0008] In one implementation of the present application, n is a natural number between 6 and 9.

[0009] In one implementation of the present application, k is a natural number between 1 and 4.

[0010] In one implementation of the present application, h is a natural number between 1 and 4.

[0011] In one implementation of the present application, s is a natural number between 1 and 4.

[0012] In one implementation of the present application, s is 1.

[0013] In one implementation of the present application, HyT is selected from the following structures:

[0014] In one implementation of the present application, the neuraminidase inhibitor includes at least one of the following compounds L7 to compound L19:

[0015]

[0016] The second aspect of the present application discloses a derivative of the neuraminidase inhibitor as described in the first aspect of the present application, including a pharmaceutically acceptable salt, stereoisomer, ester, prodrug, solvate, or deuterated compound.

[0017] The third aspect of the present application discloses a preparation method of a neuraminidase inhibitor based on a hydrophobic tag technology, including:

[0018]

[0019] and HyT-NH 2 React under the conditions of adding HATU and DIPEA; subsequently add hydrochloric acid for reaction to remove the Boc protecting group; subsequently react with oseltamivir under the conditions of adding TEA, CDI, and DMF to obtain the neuraminidase inhibitor;

[0020] Or, and HyT-NH 2 React under the conditions of adding HATU and DIPEA; subsequently add lithium hydroxide and water, and react at 50 °C; subsequently react with oseltamivir under the conditions of adding HATU and DIPEA to obtain the neuraminidase inhibitor;

[0021] Among them, n is a natural number between 2 and 10, k is a natural number between 0 and 10, h is a natural number between 0 and 10, s is a natural number between 1 and 5, and HyT is selected from the following structures:

[0022] The fourth aspect of the present application discloses a pharmaceutical composition, comprising the neuraminidase inhibitor as described in the first aspect of the present application or the derivative as described in the second aspect, and comprising one or more pharmaceutically acceptable excipients.

[0023] The fifth aspect of the present application discloses the use of the neuraminidase inhibitor as described in the first aspect of the present application or the pharmaceutical composition as described in the fourth aspect in the preparation of a drug for treating and / or preventing diseases related to influenza virus infection.

[0024] The sixth aspect of the present application discloses the use of the neuraminidase inhibitor as described in the first aspect of the present application or the pharmaceutical composition as described in the fourth aspect in the preparation of a drug for treating diseases related to oseltamivir resistance.

[0025] The seventh aspect of the present application discloses the use of the neuraminidase inhibitor as described in the first aspect of the present application or the pharmaceutical composition as described in the fourth aspect in the preparation of a drug for inhibiting the activity of influenza A virus carrying the H274Y mutation, wherein the influenza A virus includes at least one of H1N1 and H5N1.

[0026] The beneficial effects of the present application are as follows:

[0027] The neuraminidase inhibitor based on the hydrophobic tag technology of the present application has enhanced antiviral activity and effective oseltamivir resistance reversal activity, providing a new drug for the treatment of influenza virus infection, especially oseltamivir-resistant virus infection diseases. Description of the Drawings

[0028] Figure 1 It is a result graph of the degradation activity of NA protein in 293T cells treated with different compounds according to Example 2 of the present application.

[0029] Figure 2 It is a result graph of the NP protein expression in MDCK cells treated with different compounds according to Example 4 of the present application.

[0030] Figure 3 It is a result graph of molecular docking according to Example 5 of the present application. Detailed Embodiments

[0031] The present application will be further described in detail below in conjunction with the specific embodiments and the accompanying drawings. In the following embodiments, many detailed descriptions are provided to enable a better understanding of the present application. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other materials or methods. In some cases, some operations related to the present application are not shown or described in the specification, which is to avoid the core part of the present application being overwhelmed by excessive descriptions. For those skilled in the art, it is not necessary to describe these related operations in detail, and the related operations can be fully understood based on the description in the specification and the general technical knowledge in the art.

[0032] In addition, the features, operations or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can also be reordered or adjusted in a manner obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for clearly describing a certain embodiment and do not mean that they are the necessary sequences, unless it is stated that a certain sequence must be followed. Unless otherwise defined, all scientific and technical terms used in the present application have the same meaning as commonly understood by those skilled in the technical field related to the present application.

[0033] The term "pharmaceutically acceptable salt" includes acid addition salts and base addition salts.

[0034] The term "stereoisomer" includes enantiomers, diastereomers and geometric isomers. Some compounds of the present application have cycloalkyl groups, which can be substituted on more than one carbon atom. In this case, all geometric forms, including cis and trans, and their mixtures, are within the scope of the present application.

[0035] The term "solvate" refers to the physical combination of a compound of the present application with one or more solvent molecules. This physical combination includes various degrees of ionic and covalent bonding, including hydrogen bonding. In some cases, the solvate can be separated, for example, when one or more solvent molecules are incorporated into the crystal lattice of a crystalline solid. Solvates include solution-phase and separable solvates. Representative solvates include ethanolates, methanolates, etc.

[0036] The term "ester" refers to a compound formed by the reaction of a carboxylic acid and an alcohol. In medicinal chemistry, esters are often used to modify the solubility, stability and bioavailability of drugs.

[0037] The term "prodrug" refers to a form of a compound of formula I that is suitable for administration to a patient, has no excessive toxicity, irritation, allergic reaction, etc., and is effective for its intended purpose, including acetal, ester and zwitterionic forms. The prodrug is converted in the body, such as by hydrolysis in the blood, to obtain the parent compound.

[0038] The term "solvate" refers to a complex formed by the binding of a drug molecule and a solvent molecule through non-covalent bonds (such as hydrogen bonds, van der Waals forces, etc.). For example, a hydrate.

[0039] The term "deuterated compound" refers to the replacement of some or all of the hydrogen atoms ( 1 H) in a drug molecule with deuterium ( 2 H, i.e., deuterium).

[0040] The term "treatment" refers to preventing, curing, reversing, weakening, alleviating, minimizing, inhibiting, suppressing, and / or stopping one or more clinical symptoms of a disease after the onset of the disease.

[0041] The term "prevention" refers to, before the onset of a disease, through treatment to avoid, minimize, or make it difficult for the disease to occur or develop.

[0042] Currently, existing anti-influenza drugs have limited therapeutic effects on influenza infection due to their serious side effects and drug resistance problems. Given the differences between viral target proteins and human proteins, PROTAC (Proteolysis Targeting Chimeras) technology can achieve complete degradation of viral proteins, thereby enhancing antiviral effects and reducing the occurrence of drug resistance. In recent years, PROTACs have been used to target antiviral targets such as coronavirus 3CLpro, influenza NA protein, and hepatitis C virus (HCV) NS3 protein. Hydrophobic tag (HyT) technology uses ligands with hydrophobic tags to mimic the hydrophobic properties of partially unfolded proteins. These modified proteins are recognized by molecular chaperones such as heat shock proteins (such as Hsp70 and Hsp90) and are degraded through the proteasome. Compared with PROTACs technology, HyT technology provides an effective method for improving drug properties by virtue of advantages such as a lower molecular weight and a smaller number of hydrogen bond donors / acceptors (HBDs / HBAs).

[0043] In this application, the amino group of oseltamivir is modified to utilize its additional binding cavity to enhance antiviral effects and combat drug resistance. In this application, a hydrophobic tag HyT is connected to the amino group of oseltamivir through flexible and rigid chains (such as alkyl and polyethylene glycolated structures) to design oseltamivir-derived HyTTDs (HyT-based Targeted Protein Degraders). The antiviral effects against the H1N1-H274Y virus strain were evaluated in vitro, their effectiveness was confirmed by immunofluorescence, and the ability of these compounds to degrade neuraminidase (NA) protein was evaluated by Western blot analysis. Finally, their binding interactions were predicted through molecular docking studies. The neuraminidase inhibitors based on hydrophobic tag technology in this application have enhanced antiviral activity and effective oseltamivir drug resistance reversal activity.

[0044] The present application will be further described in detail below through specific embodiments. The following embodiments are only for further illustration of the present application and should not be construed as limitations on the present application. In this embodiment, unless otherwise specified, the reagents and instruments used are all commercially available, and the experimental operations are carried out in accordance with the product instructions and conventional experimental specifications. Among them, analytical thin-layer chromatography was carried out on silica gel plates with a thickness of 0.20 mm (purchased from Ocean Company, Qingdao, Shandong, China), and equipped with a QF-254 ultraviolet lamp. Column chromatography was performed using Ocean silica gel 60 (300-400 mesh). Nuclear magnetic resonance (NMR) spectra were recorded on a Bruker 600 or 400 MHz spectrometer, using CDCl 3 or DMSO-d6 as the solvent and tetramethylsilane (TMS) as the internal standard. High-resolution mass spectrometry (HRMS) was recorded on a Thermo-Fisher Orbitrap Fusion equipped with an electrospray ionization probe (ESI). Madin-Darby canine kidney cells (MDCK) and 293T cells were purchased from the American Type Culture Collection (ATCC, Manassas, Virginia) and cultured in Dulbecco's modified Eagle's medium containing 10% fetal bovine serum and 1% antibiotics (penicillin and streptomycin) (both from Gibco, Thermo Fisher Scientific, USA). The H1N1 influenza strain (A / Puerto Rico / 8 / 1934, containing NA-H274Y) was also purchased from ATCC. The virus infection experiments were carried out in BSL-2 laboratories at Guangzhou Medical University and Southern Medical University. All animal experiments were strictly carried out in accordance with the "Technical Guidelines for Non-Clinical Pharmacokinetics Studies of Drugs" issued by the National Medical Products Administration (NMPA) and the relevant guidelines of the International Council for Harmonization (ICH).

[0045] Example 1

[0046] (1) Synthesis of Compounds L1-L6. The synthetic route is shown as follows:

[0047]

[0048] In the above synthetic route, the compound oseltamivir on the left is converted into the compound on the right through reaction a or reaction b. Reaction a: Using the corresponding acids (1-adamantaneacetic acid, (+)-menthyloxyacetic acid, 2,2-diphenylacetic acid, and 9-fluorenylacetic acid respectively), in the presence of HATU (O-(7-azabenzotriazol-1-yl)-N,N',N''-tetramethyluronium hexafluorophosphate) and DIPEA (diisopropylethylamine) in dry dichloromethane (DCM), the reaction time is 4 hours; finally, compounds L1, L2, L3, and L4 are formed respectively. Reaction b is divided into two steps: The first step uses TEA (triethylamine) and CDI (1,1'-carbonyldiimidazole dicyclohexyl) in DMF (N,N-dimethylformamide), the reaction time is 1 hour; the second step uses the corresponding amines (5-norbornene-2-methylamine or 1-adamantanemethylamine respectively), at room temperature, the reaction time is 10 hours; finally, compounds L5 and L6 are formed respectively.

[0049] Compound L1 - ethyl (3R,4R,5R)-4-acetamido-5-[2-((3R,5R,7R)-adamantan-1-yl)acetamido]-3-(pent-3-yloxy)cyclohex-1-ene-1-carboxylate: Using oseltamivir (0.53 g, 1.69 mmol) and 1-adamantaneacetic acid (0.3 g, 1.5 mmol) as starting materials, finally, white solid L1 (0.47 g, yield 64.85%) is obtained. 1 H NMR(600MHz,DMSO-d 6 )δ7.93(d,J=9.2Hz,1H),7.56(d,J=8.9Hz,1H),6.68(t,J=2.5Hz,1H),4.20–4.14(m,2H),4.12–4.08(m,1H),3.84–3.77(m,1H),3.76–3.74(m,1H),3.46–3.42(m,1H),2.24–2.17(m,1H),1.98–1.92(m,3H),1.87(d,J=12.7Hz,1H),1.83(s,1H),1.81(s,3H),1.70(d,J=12.2Hz,3H),1.61(d,J=12.2Hz,6H),1.58–1.53(m,3H),1.51–1.38(m,5H),1.26(t,J=7.1Hz,3H),0.88(t,J=7.4Hz,3H),0.81(t,J=7.4Hz,3H). 13 C NMR(151MHz,DMSO-d 6) δ 170.1, 169.9, 166.0, 138.8, 129.9, 129.0, 81.6, 75.9, 67.9, 67.6, 60.9, 53.6, 50.7, 47.6, 42.6, 42.5, 40.5, 38.7, 38.6, 36.9, 32.5, 31.2, 30.4, 30.3, 28.9, 28.6, 26.1, 25.6, 23.9, 23.7, 23.3, 22.9, 14.5, 14.4, 11.4, 11.3, 9.9, 9.4. HRMS(ESI): [M+H] + calculated for C 28 H 45 N 2 O 5 : 489.3328, found: 489.3321.

[0050] Compound L2 - Ethyl (3R,4R,5R)-4-acetamido-5-[2-(((1S,2R,5S)-2-isopropyl-5-methylcyclohexyloxy)acetylamino]-3-(pent-3-yloxy)cyclohex-1-ene-1-carboxylate: Starting from oseltamivir (0.48 g, 1.54 mmol) and 2-[((1S,2R,5S)-2-isopropyl-5-methylcyclohexyloxy)]acetic acid (0.3 g, 1.4 mmol), white solid L2 (0.47 g, yield 69.01%) was finally obtained. 1 H NMR(600MHz,CDCl 3 ) δ 7.16 (d, J = 7.6 Hz, 1H), 6.83–6.81 (m, 1H), 5.77 (d, J = 7.9 Hz, 1H), 4.22–4.18 (m, 2H), 4.13–4.13 (m, 2H), 4.04–4.01 (m, 1H), 3.99 (d, J = 15.3 Hz, 1H), 3.86 (d, J = 15.2 Hz, 1H), 3.84–3.81 (m, 1H), 3.14–3.11 (m, 1H), 2.77–2.72 (m, 1H), 2.42–2.36 (m, 1H), 2.16–2.10 (m, 1H), 1.99–1.95 (m, 1H), 1.94 (s, 3H), 1.84 (s, 1H), 1.67–1.61 (m, 2H), 1.54–1.48 (m, 4H), 1.31 (s, 4H), 0.94–0.86 (m, 15H), 0.77 (d, J = 7.0 Hz, 3H). 13 C NMR(151MHz,CDCl 3)δ171.4,170.5,166.0,137.5,129.2,82.5,80.5,75.6,67.7,61.0,53.4,47.8,47.3,40.0,34.4,31.5,30.3,26.2,25.8,25.7,23.2,23.1,22.2,21.0,16.1,14.2,9.5,9.4.HRMS(ESI):[M+H] + calculated forC 28 H 49 N 2 O 6 :509.3591,found:509.3581.

[0051] Compound L3 - Ethyl (3R,4R)-4-acetamido-5-[(3,3-diphenylprop-1-en-2-yl)amino]-3-(pentan-3-yloxy)cyclohex-1-ene-1-carboxylate: Starting from oseltamivir (0.48 g, 1.55 mmol) and 2,2-diphenylacetic acid (0.3 g, 1.41 mmol), white solid L3 (0.45 g, yield 63.23%) was obtained. 1 H NMR(600MHz,DMSO-d 6 )δ8.26(d,J=9.1Hz,1H),7.79(d,J=9.3Hz,1H),7.30(dd,J=5.3,2.7Hz,8H),7.24–7.20(m,2H),6.65–6.63(m,1H),4.88(s,1H),4.16–4.11(m,2H),4.09–4.05(m,1H),4.00–3.93(m,1H),3.79–3.74(m,1H),2.47(dd,J=17.7,5.2Hz,1H),2.24–2.17(m,1H),1.44–1.37(m,6H),1.35–1.30(m,1H),1.21(t,J=7.1Hz,4H),0.82(t,J=7.4Hz,3H),0.73(t,J=7.4Hz,3H). 13 C NMR(151MHz,DMSO-d 6 )δ171.2,169.9,165.9,140.8,140.8,139.1,129.0,128.9,128.9,128.7,128.6,127.0,81.6,75.7,60.9,57.1,54.0,47.8,40.5,31.1,26.2,25.6,22.8,14.5,9.9,9.4.HRMS(ESI):[M+Na]+ Calculated for C 30 H 38 N 2 O 5 Na: 531.3410, found: 531.3403.

[0052] Compound L4 - Ethyl (3R,4R,5R)-5-[2-(9H-fluoren-9-yl)acetamido]-4-acetamido-3-(pentan-3-yloxy)cyclohex-1-ene-1-carboxylate: Starting from oseltamivir (0.45 g, 1.46 mmol) and fluoren-9-ylacetic acid (0.3 g, 1.33 mmol), white solid L4 (0.45 g, yield 65.78%) was obtained. 1 1H NMR (600 MHz, DMSO-d 6 ) δ 7.96 (d, J = 9.2 Hz, 1H), 7.88 (dd, J = 11.9, 8.1 Hz, 2H), 7.59 (d, J = 7.5 Hz, 1H), 7.54 (d, J = 7.6 Hz, 1H), 7.39 (t, J = 7.5 Hz, 2H), 7.36–7.31 (m, 2H), 6.68 (s, 1H), 4.33 (t, J = 7.5 Hz, 1H), 4.21–4.10 (m, 4H), 3.82–3.79 (m, 1H), 2.61 (dd, J = 17.4, 5.4 Hz, 1H), 2.26–2.19 (m, 1H), 1.76 (s, 3H), 1.51–1.33 (m, 5H), 1.26–1.23 (m, 4H), 1.15 (d, J = 6.7 Hz, 1H), 1.02 (dd, J = 12.1, 6.6 Hz, 1H), 0.85 (t, J = 7.3 Hz, 3H), 0.78 (t, J = 7.3 Hz, 3H). 13 13C NMR (151 MHz, DMSO-d 6 ) δ 171.0, 127.6, 127.5, 120.4, 81.6, 75.7, 61.0, 54.0, 48.0, 43.9, 26.2, 25.7, 14.6, 9.9, 9.5. HRMS (ESI): [M + H] + Calculated for C 31 H 39 N 2 O 5 : 519.2859, found: 519.2852.

[0053] Compound L5 - ethyl (3R,4R,5R)-4-acetamido-5-[3-(bicyclo[2.2.1]hept-5-en-2-ylmethyl)ureido]-3-(pent-3-yloxy)cyclohex-1-ene-1-carboxylate: Starting from oseltamivir (0.5 g, 1.6 mmol) and 5-norbornene-2-methylamine (0.21 g, 1.76 mmol), a light yellow solid L5 (0.32 g, yield 43.51%) was obtained. 1 HNMR(600MHz,DMSO-d 6 )δ7.84(dd,J=8.9,4.7Hz,1H),6.67–6.63(m,1H),6.13(dd,J=5.7,3.1Hz,1H),6.11–6.04(m,1H),5.97–5.91(m,1H),5.66–5.55(m,1H),4.19–4.10(m,2H),4.08–4.01(m,1H),3.78–3.67(m,2H),3.42–3.37(m,1H),3.33(d,J=4.7Hz,1H),2.80–2.72(m,2H),2.66–2.55(m,2H),2.54–2.44(m,3H),2.17–2.00(m,2H),1.86–1.79(m,3H),1.76–1.71(m,1H),1.51–1.35(m,4H),1.33–1.28(m,1H),1.26–1.21(m,4H),0.91–0.75(m,6H). 13 CNMR(151MHz,DMSO-d 6 )δ133.5,82.1,76.4,50.0,42.9,41.0,40.9,40.7,40.6,40.4,40.3,40.2,26.7,26.3,23.8,15.1,10.4,10.0.HRMS(ESI):[M+H] + calculated for C 25 H 40 N 3 O 5 + :462.2968,found:462.2957.

[0054] Compound L6 - ethyl (3R,4R,5R)-4-acetamido-5-[3-(((3R,5R,7R)-adamantan-1-yl)methyl)ureido]-3-(pentan-3-yloxy)cyclohex-1-ene-1-carboxylate: Starting from oseltamivir (0.5 g, 1.6 mmol) and 1-adamantylmethylamine (0.29 g, 1.76 mmol), a light yellow solid L6 (0.42 g, yield 53.21%) was obtained. 1 H NMR (600 MHz, DMSO-d 6 ) δ 8.40 (d, J = 7.9 Hz, 1H), 7.19 (t, J = 2.5 Hz, 1H), 6.56 (t, J = 6.2 Hz, 1H), 6.23 (d, J = 7.7 Hz, 1H), 4.72–4.62 (m, 2H), 4.61–4.56 (m, 1H), 4.32–4.25 (m, 2H), 3.97–3.92 (m, 1H), 3.88 (s, 1H), 3.34 (dd, J = 13.3, 6.5 Hz, 1H), 3.19–3.11 (m, 2H), 3.08–3.02 (m, 2H), 2.61–2.53 (m, 1H), 2.35 (s, 3H), 2.22 (d, J = 12.0 Hz, 3H), 2.12 (d, J = 12.0 Hz, 3H), 2.04–1.89 (m, 10H), 1.78 (t, J = 7.0 Hz, 3H), 1.40 (t, J = 7.4 Hz, 3H), 1.33 (t, J = 7.3 Hz, 3H). 13 C NMR (151 MHz, DMSO-d 6 ) δ 139.3, 82.1, 76.5, 61.4, 54.7, 52.1, 49.0, 41.0, 40.8, 40.8, 40.7, 40.6, 40.4, 40.3, 40.1, 37.7, 34.6, 32.9, 28.8, 26.7, 26.3, 23.8, 15.1, 10.4, 10.0. HRMS (ESI): [M+H] + calculated for C 28 H 46 N 3 O 5 : 504.3437, found: 504.3428.

[0055] (2) Synthesis of Compounds L7 - L19

[0056] Overall synthetic route: Using HATU (O-(7-azabenzotriazol-1-yl)-N,N',N”-tetramethyluronium hexafluorophosphate) as the condensing reagent and DIPEA (diisopropylethylamine) as the base, the corresponding Boc (tert-butoxycarbonyl)-protected amino alkanoic acids (1a-g, namely 1a, 1b, 1c, 1d, 1e, 1f, 1g) react with their respective HyT-NH 2 to form intermediates 2a-g (namely 2a, 2b, 2c, 2d, 2e, 2f, 2g). Subsequently, these intermediates are deprotected by 4M hydrochloric acid to generate 3a-g (namely 3a, 3b, 3c, 3d, 3e, 3f, 3g). Meanwhile, oseltamivir is activated with CDI (1,1'-carbodiimide dicyclohexyl) in the presence of TEA (triethylamine), and then condensed with the corresponding intermediates 3a-g to obtain compounds L7, L10-L13, L17-L19. Under the action of HATU and DIPEA, methyl alkyl carboxylates 4a-e (namely 4a, 4b, 4c, 4d, 4e) react with their respective HyT-NH 2 to form intermediates 5a-e (namely 5a, 5b, 5c, 5d, 5e). Then, these intermediates are hydrolyzed with lithium hydroxide to remove the methyl ester protecting group, generating intermediates 6a-e (namely 6a, 6b, 6c, 6d, 6e). Finally, 6a-e is condensed with oseltamivir to synthesize compounds L8-L9, L14-L16. Among them, the specific conditions for each reaction are as follows:

[0057] Reaction c: Starting from compounds 1a-g, the reaction is carried out with the corresponding HyT-NH 2 , HATU, and DIPEA in dry dichloromethane (DCM) at room temperature for 4 hours to obtain compounds 2a-g.

[0058] Reaction d: To remove the Boc protecting group, the corresponding Boc compound (1.0 equivalent) is dissolved in a solvent, and then a 4M hydrochloric acid / 1,4-dioxane solution (10.0 equivalents) is added at room temperature. The mixture is stirred at room temperature for 2 hours, and the reaction progress is monitored using thin-layer chromatography (TLC). After removing dioxane under reduced pressure, the next reaction is carried out directly without further treatment. Thus, compounds 2a-g react to obtain compounds 3a-g.

[0059] Reaction e: Under a nitrogen atmosphere, oseltamivir (1.0 equiv) and triethylamine (1.0 equiv) were dissolved in DMF. Then, CDI (1.0 equiv) was added at room temperature, and the mixture was stirred for 1 hour. Subsequently, a DMF solution of the corresponding amine (1.1 equiv) was added, and stirring was continued for 10 hours. After the reaction was completed, the mixture was poured into water and extracted with dichloromethane. The organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, and filtered. The filtrate was concentrated to obtain the crude product, which was finally purified by column chromatography to obtain the target product. That is, Compounds 3a-g were converted to Compounds L7, L10-L13, and L17-L19 through the following two-step reaction: 1) React oseltamivir, TEA, and CDI in DMF (N,N-dimethylformamide) for 1 hour; 2) Continue the reaction at room temperature for 10 hours.

[0060] Reaction f: Starting from Compounds 4a-e, 1-imino-methyladamantylamine, HATU, and DIPEA were reacted in dry DCM for 4 hours to obtain Compounds 5a-e.

[0061] Reaction g: In a single-necked flask, the corresponding ester (1.0 equiv), lithium hydroxide (5.0 equiv), and water were added, and the reaction was carried out at 50 °C for 4 hours. TLC analysis showed that the reaction was complete. The solution was acidified to pH 1 to produce a precipitate. The precipitate was filtered and dried to obtain the target product. Thus, Compounds 5a-e were reacted to obtain Compounds 6a-e.

[0062] Reaction h: In a round-bottom flask, the corresponding carboxylic acid raw material (1.0 equiv) was dissolved in anhydrous dichloromethane. Then, HATU (1.2 equiv), DIPEA (2.0 equiv), and oseltamivir (1.1 equiv) were added sequentially. The reaction mixture was stirred at room temperature for 4 hours. After the reaction was completed, the reaction mixture was poured into water, the organic layer was separated, and washed with saturated brine. Then, the solution was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. Thus, Compounds 6a-e were reacted to obtain Compounds L8-L9 and L14-L16.

[0063] Compounds L7-L19 were synthesized according to the overall synthetic route. Specifically, the synthesis methods of each compound or its intermediate are as follows:

[0064] Compound 2a - tert-butyl (5-((bicyclo[2.2.1]hept-5-en-2-ylmethyl)amino)-5-oxopentyl)carbamate: Using Boc-5-aminopentanoic acid (2.0 g, 9.21 mmol) and 5-norbornene-2-methylamine (1.24 g, 10.13 mmol) as starting materials, light yellow solid 2a (1.22 g, yield 41.23%) was obtained.

[0065] Compound 3a - 5 - Amino - N - (bicyclo[2.2.1]hept - 5 - en - 2 - ylmethyl)pentanamide: A pale yellow oil 3a (0.81 g, yield 96.36%) was obtained.

[0066] Compound L7 - Ethyl (3R,4R,5R) - 4 - acetamido - 5 - [3 - (5 - ((bicyclo[2.2.1]hept - 5 - en - 2 - ylmethyl)amino) - 5 - oxopentyl)ureido] - 3 - (pent - 3 - yloxy)cyclohex - 1 - ene - 1 - carboxylate: Using oseltamivir (0.77 g, 2.47 mmol) and 3a (0.5 g, 2.25 mmol) as starting materials, a white solid L7 (0.68 g, yield 54.34%) was obtained. 1 HNMR(600MHz,DMSO - d 6 )δ7.82(d,J = 8.4Hz,1H),7.73(t,J = 5.7Hz,1H),6.63(t,J = 2.5Hz,1H),6.14(dd,J = 5.7,3.0Hz,1H),6.06(t,J = 5.6Hz,1H),5.95(dd,J = 5.8,2.8Hz,1H),5.58(d,J = 7.7Hz,1H),4.16–4.09(m,2H),4.06–4.00(m,1H),3.76–3.66(m,2H),3.41–3.96(m,1H),3.01–2.88(m,2H),2.82–2.77(m,1H),2.75(d,J = 13.7Hz,1H),2.66–2.58(m,2H),2.18–2.11(m,1H),2.07–1.99(m,3H),1.79(s,3H),1.54–1.28(m,10H),1.28–1.19(m,5H),1.14–1.00(m,1H),0.84(t,J = 7.4Hz,3H),0.77(t,J = 7.4Hz,3H). 13 CNMR(151MHz,DMSO - d 6)δ171.2,171.0,169.0,165.0,157.2,137.6,136.3,135.9,135.8,131.9,129.1,128.1,80.5,74.7,59.8,53.0,48.3,47.6,44.0,43.1,43.1,43.0,42.0,41.3,40.6,39.5,38.4,38.2,37.8,37.3,34.5,31.0,30.6,29.8,29.2,29.0,28.0,26.0,25.1,24.6,22.2,22.2,20.5,19.6,13.5,13.3,8.8,8.4.HRMS(ESI):[M+H] + calculated for C 30 H 49 N 4 O 6 : 561.3652, found: 561.3638.

[0067] Compound 5a - Methyl 8 - [((3r,5r,7r)-adamantan - 1 - yl)methylamino]-8 - oxooctanoate: Starting from monomethyl octanedioate (2.0 g, 10.6 mmol) and 1 - adamantylmethylamine (1.92 g, 11.66 mmol), light yellow solid 5a (1.71 g, yield 48.23%) was obtained.

[0068] Compound 6a - 8 - [((3r,5r,7r)-adamantan - 1 - yl)methylamino]-8 - oxooctanoic acid: Light yellow oil 6a (1.39 g, yield 84.96%) was obtained.

[0069] Compound L8 - Ethyl (3R,4R,5R)-4 - acetamido - 5 - [8 - [((3r,5r,7r)-adamantan - 1 - yl)methylamino]-8 - oxooctanamido]-3-(pentan - 3 - yloxy)cyclohex - 1 - ene - 1 - carboxylate: Starting from 6a (0.5 g, 1.55 mmol) and oseltamivir (0.53 g, 1.7 mmol), white solid L8 (0.49 g, yield 51.43%) was obtained. 1 HNMR(600MHz, DMSO - d 6)δ 7.84 (dd, J=9.4, 5.8 Hz, 1H), 7.73 (t, J=5.7 Hz, 1H), 7.64 (t, J=8.5 Hz, 1H), 6.64 (t, J=2.5 Hz, 1H), 6.19–6.08 (m, 1H), 5.95–5.95 (m, 1H), 4.16–4.10 (m, 2H), 4.09–4.08 (m, 1H), 3.95–3.88 (m, 1H), 3.79–3.72 (m, 1H), 3.41–3.36 (m, 1H), 3.35–3.29 (m, 2H), 2.83–2.78 (m, 1H), 2.78–2.72 (m, 2H), 2.67–2.59 (m, 1H), 2.50–2.45 (m, 1H), 2.24–2.13 (m, 2H), 2.07–1.98 (m, 4H), 1.79–1.72 (m, 4H), 1.51–1.39 (m, 8H), 1.38–1.33 (m, 1H), 1.31–1.28 (m, 1H), 1.26–1.17 (m, 8H), 0.86–0.81 (m, 4H), 0.77 (t, J=7.4 Hz, 3H), 0.46–0.42 (m, 1H). 13 C NMR (151 MHz, DMSO-d 6 )δ 172.4, 172.3, 172.2, 169.8, 165.9, 138.9, 137.3, 137.0, 136.8, 133.0, 129.0, 81.6, 75.6, 60.9, 54.2, 49.4, 47.6, 45.1, 44.2, 44.1, 44.1, 43.0, 42.4, 41.6, 40.5, 39.3, 38.9, 36.2, 35.9, 35.9, 30.8, 30.2, 29.2, 29.1, 29.1, 26.2, 25.8, 25.8, 25.7, 23.3, 14.5, 9.9, 9.4. HRMS (ESI): [M+Na] + calculated for C 35 H 57 N 3 O 6 Na: 638.4145, found: [M+Na] + : 638.4132.

[0070] Compound 5b - Methyl 8-[(bicyclo[2.2.1]hept-5-en-2-ylmethyl)amino]-8-oxooctanoate: Starting from monomethyl octanedioate (2.0 g, 10.6 mmol) and 5-norbornene-2-methanamine (1.43 g, 11.66 mmol), light yellow solid 5b (1.54 g, yield 49.73%) was obtained.

[0071] Compound 6b - 8-[(bicyclo[2.2.1]hept-5-en-2-ylmethyl)amino]-8-oxooctanoic acid: Light yellow oily substance 6b (1.3 g, yield 88.46%) was obtained.

[0072] Compound L9 - Ethyl (3R,4R,5R)-4-acetamido-5-[8-((bicyclo[2.2.1]hept-5-en-2-ylmethyl)amino)-8-oxooctanamido]-3-(pentan-3-yloxy)cyclohex-1-ene-1-carboxylate: Starting from 6b (0.5 g, 1.79 mmol) and oseltamivir (0.53 g, 1.7 mmol), white solid L9 (0.49 g, yield 51.43%) was obtained. 1 HNMR(600MHz,DMSO-d 6 )δ7.84(d,J=9.3Hz,1H),7.64(d,J=9.0Hz,1H),7.59(t,J=6.3Hz,1H),6.64(t,J=2.6Hz,1H),4.17–4.11(m,2H),4.09–4.06(m,1H),3.95–3.88(m,1H),3.77–3.72(m,1H),3.40–3.36(m,1H),2.75(d,J=6.2Hz,2H),2.50–2.44(m,1H),2.24–2.17(m,1H),2.09(t,J=7.4Hz,2H),2.02–1.98(m,2H),1.90(dd,J=6.0,3.2Hz,3H),1.77(s,3H),1.67–1.62(m,3H),1.60–1.54(m,3H),1.48–1.44(m,4H),1.41(d,J=3.0Hz,6H),1.22(t,J=7.1Hz,5H),0.84(t,J=7.4Hz,3H),0.77(t,J=7.4Hz,3H). 13 C NMR(151MHz,DMSO-d 6)δ172.7,172.3,169.8,165.9,138.9,129.0,81.6,75.6,60.9,54.2,54.1,50.5,47.7,40.5,40.3,38.7,37.0,36.2,35.9,34.1,30.8,29.0,28.9,28.2,26.8,26.2,25.9,25.8,25.7,23.2,18.5,17.2,14.5,9.9,9.4.HRMS(ESI):[M+H] + calculated forC 32 H 52 N 3 O 6 :574.3856,found:574.3847.

[0073] Compound 2b - tert-butyl (9 - (((1r,3R,5S,7r)-3,5-dimethyladamantan-1-yl)amino)-9-oxononyl)carbamate: Starting from Boc-9-aminononanoic acid (2.0 g, 7.32 mmol) and memantine (1.44 g, 8.05 mmol), light yellow solid 2b (1.31 g, yield 41.73%) was obtained.

[0074] Compound 3b - 9-amino-N-((1r,3R,5S,7r)-3,5-dimethyladamantan-1-yl)nonanamide: Light yellow oily substance 3b (0.96 g, yield 96.46%) was obtained.

[0075] Compound L10 - ethyl (3R,4R,5R)-4-acetamido-5-(8-((bicyclo[2.2.1]hept-5-en-2-ylmethyl)amino)-8-oxooctanamido)-3-(3-pentyloxy)cyclohex-1-ene-1-carboxylate: Starting from oseltamivir phosphate (0.51 g, 1.63 mmol) and 3b (0.5 g, 1.49 mmol), L10 was obtained as a white solid (0.41 g, 41.43% yield). 1 HNMR(600MHz,DMSO-d 6)δ 7.88 (d, J = 7.6 Hz, 1H), 7.23 (s, 1H), 6.62 (s, 1H), 6.07 (s, 1H), 5.61 (d, J = 6.8 Hz, 1H), 4.18–4.08 (m, 2H), 4.05 (d, J = 6.5 Hz, 1H), 3.71 (d, J = 6.9 Hz, 2H), 3.40–3.35 (m, 1H), 2.99–2.94 (m, 1H), 2.92–2.85 (m, 1H), 2.62–2.55 (m, 1H), 2.04 (s, 2H), 1.97 (t, J = 7.3 Hz, 2H), 1.78 (s, 3H), 1.74–1.70 (m, 2H), 1.55 (t, J = 9.1 Hz, 4H), 1.46–1.37 (m, 6H), 1.34–1.30 (m, 3H), 1.21 (t, J = 6.5 Hz, 12H), 1.07 (s, 2H), 0.83 (t, J = 7.3 Hz, 4H), 0.78 (d, J = 13.4 Hz, 10H). 13 C NMR (151 MHz, DMSO-d 6 )δ 172.1, 170.0, 166.1, 158.2, 138.7, 129.2, 81.6, 75.8, 60.9, 54.1, 52.5, 50.8, 48.6, 47.6, 42.8, 40.5, 36.6, 32.3, 32.1, 30.6, 30.4, 30.0, 29.3, 29.2, 29.0, 26.8, 26.2, 25.9, 25.7, 23.3, 14.5, 9.9, 9.5. HRMS (ESI): [M + H] + calculated for C 38 H 65 N 4 O 6 : 673.4904, found: 673.4985.

[0076] Compound L11——(3R,4R,5S)-4-Acetamido-5-[3-(9-(((1r,3R,5S,7r)-3,5-Dimethyladamantan-1-yl)amino)-9-oxononyl)ureido]-3-(3-pentyloxy)cyclohex-1-ene-1-carboxylic acid: Starting from L10 (0.5 g, 1.49 mmol), L11 was obtained as a white solid (0.21 g, 41.43%). 1 H NMR (600 MHz, DMSO-d 6)δ12.53(s,1H),7.81(d,J=8.6Hz,1H),7.22(s,1H),6.61(t,J=2.5Hz,1H),6.03(t,J=5.7Hz,1H),5.55(d,J=7.9Hz,1H),4.04–3.99(m,1H),3.75–3.66(m,2H),3.40–3.36(m,1H),3.01–2.96(m,1H),2.91–2.86(m,1H),2.58(dd,J=17.1,4.5Hz,1H),2.06–2.02(m,1H),2.02–1.95(m,3H),1.79(s,3H),1.73(d,J=3.1Hz,2H),1.56(t,J=9.2Hz,4H),1.47–1.40(m,5H),1.35–1.28(m,4H),1.23(d,J=9.4Hz,11H),1.09(s,2H),0.84(t,J=7.4Hz,3H),0.80(s,6H),0.78(t,J=7.4Hz,3H). 13 C NMR(151MHz,DMSO-d 6 )δ172.1,170.0,167.8,158.3,138.2,129.8,81.5,75.9,54.3,52.5,52.4,50.8,48.7,47.6,47.5,42.8,40.5,36.6,32.3,32.2,30.6,30.4,30.0,29.3,29.2,29.0,26.8,26.2,25.9,25.7,23.3,9.9,9.5.HRMS(ESI):[M+H] + calculated for C 36 H 61 N 4 O 6 :645.4591,found:645.4578.

[0077] Compound 2c - tert-Butyl (9 - ((((3r,5r,7r)-adamantan-1-yl)methyl)amino)-9-oxononyl)carbamate: Using Boc-9-aminononanoic acid (2.0 g, 7.32 mmol) and 1-adamantylmethylamine (1.2 g, 8.05 mmol) as starting materials, 2c was obtained as a light yellow solid (1.42 g, 44.37%).

[0078] Compound 3c - N - ((((3r,5r,7r)-adamantan-1-yl)methyl)-9-aminononanamide: 3c was obtained as a light yellow oil (1.05 g, 96.78%).

[0079] Compound L12 - ethyl (3R,4R,5R)-4-acetamido-5-[3-(9-((((3r,5r,7r)-adamantan-1-yl)methyl)amino)-9-oxononyl)carbamoyl]-3-(pentan-3-yloxy)cyclohex-1-ene-1-carboxylate: Starting from oseltamivir (0.53 g, 1.71 mmol) and 3c (0.5 g, 1.56 mmol), L12 was obtained as a white solid (0.41 g, 40.63%). 1 H NMR (600 MHz, DMSO-d 6 ) δ 8.41 (t, J = 9.0 Hz, 1H), 8.18 (t, J = 6.3 Hz, 1H), 7.23 (d, J = 2.5 Hz, 1H), 6.62 (t, J = 5.7 Hz, 1H), 6.16 (d, J = 7.7 Hz, 1H), 4.76–4.68 (m, 2H), 4.64–4.59 (m, 1H), 4.35–4.24 (m, 2H), 4.01–3.95 (m, 1H), 3.91 (d, J = 14.2 Hz, 2H), 3.61–3.45 (m, 2H), 3.34 (d, J = 6.2 Hz, 2H), 3.20 (dd, J = 17.3, 4.4 Hz, 1H), 3.12–3.04 (m, 3H), 2.70–2.56 (m, 3H), 2.39 (d, J = 17.2 Hz, 3H), 2.28–2.12 (m, 5H), 2.11–1.88 (m, 14H), 1.86–1.78 (m, 10H), 1.43 (t, J = 7.4 Hz, 3H), 1.37 (t, J = 7.3 Hz, 3H). 13 C NMR (151 MHz, DMSO-d 6 ) δ 171.8, 169.1, 165.2, 157.3, 137.8, 128.3, 80.7, 74.9, 60.0, 53.2, 49.6, 47.7, 36.1, 35.0, 33.2, 31.2, 29.5, 28.2, 27.3, 25.9, 25.3, 25.1, 24.8, 22.3, 13.6, 9.0, 8.6. HRMS (ESI): [M+H] + calculated for C 37 H 63 N 4 O 6 : 659.4748, found: 659.4740.

[0080] Compound 2d - tert-Butyl (9-((bicyclo[2.2.1]hept-5-en-2-ylmethyl)amino)-9-oxononyl)carbamate: Starting from Boc-9-aminononanoic acid (2.0 g, 7.32 mmol) and 5-norbornene-2-methylamine (0.99 g, 8.05 mmol), 2d was obtained as a pale yellow solid (1.39 g, 45.89%).

[0081] Compound 3d - 9-Amino-N-(bicyclo[2.2.1]hept-5-en-2-ylmethyl)nonanamide: 3d was obtained as a pale yellow oil (1.0 g, 97.45%).

[0082] Compound L13 - Ethyl (3R,4R,5R)-4-acetamido-5-[3-(9-((bicyclo[2.2.1]hept-5-en-2-ylmethyl)amino)-9-oxononyl)ureido]-3-(pent-3-yloxy)cyclohex-1-ene-1-carboxylate: Starting from oseltamivir (0.53 g, 1.97 mmol) and 3d (0.5 g, 1.79 mmol), white solid L13 was obtained (0.42 g, 38.63%). 1 HNMR(600MHz,DMSO-d 6 )δ8.37–8.12(m,2H),7.17–7.06(m,1H),6.58–6.40(m,1H),6.05(d,J=8.1Hz,1H),4.68–4.57(m,2H),4.56–4.44(m,2H),4.27–4.12(m,2H),3.92–3.85(m,1H),3.84–3.75(m,3H),3.51–3.43(m,1H),3.42–3.28(m,2H),3.12–3.05(m,1H),3.03–2.91(m,3H),2.84–2.67(m,2H),2.42–2.14(m,5H),2.07–1.61(m,20H),1.39–1.20(m,6H). 13 C NMR(151MHz,DMSO-d 6 )δ174.0,170.0,166.0,158.2,140.0,139.5,138.7,129.1,129.1,127.4,81.5,75.7,70.4,70.0,70.0,69.4,60.8,54.2,48.6,44.9,44.7,39.0,31.9,30.0,26.1,25.7,23.2,22.6,19.0,14.5,9.8,9.4.HRMS(ESI):[M+H] + calculated forC34 H 57 N 4 O 6 : 617.4278, found: 617.4262.

[0083] Compound 5c - Methyl 9 - [((3r,5r,7r) - adamantan - 1 - yl)methyl]amino - 9 - oxononanoate: Starting from 9 - methoxy - 9 - oxononanoic acid (2.0 g, 9.9 mmol) and 1 - adamantanemethylamine (1.79 g, 10.89 mmol), light yellow solid 5c (1.61 g, 46.82%) was obtained.

[0084] Compound 6c - 9 - [((3r,5r,7r) - adamantan - 1 - yl)methyl]amino - 9 - oxononanoic acid: Light yellow oil 6c (1.31 g, 84.68%) was obtained.

[0085] Compound L14 - Ethyl (3R,4R,5R) - 4 - acetamido - 5 - [9 - ((((3r,5r,7r) - adamantan - 1 - yl)methyl)amino) - 9 - oxononanoylamino] - 3 - (pent - 3 - yloxy)cyclohex - 1 - ene - 1 - carboxylate: Starting from 6c (0.5 g, 1.49 mmol) and oseltamivir (0.53 g, 1.64 mmol), white solid L14 (0.37 g, 39.73%) was obtained. 1 H NMR (400 MHz, DMSO - d 6 ) δ 7.83 (dd, J = 9.2, 2.5 Hz, 1H), 7.66–7.56 (m, 2H), 6.64 (d, J = 2.4 Hz, 1H), 4.20–4.04 (m, 3H), 3.97–3.86 (m, 1H), 3.79–3.69 (m, 1H), 3.42–3.36 (m, 1H), 3.34 (s, 2H), 2.75 (d, J = 6.2 Hz, 2H), 2.24–2.15 (m, 1H), 2.09 (t, J = 7.3 Hz, 2H), 2.01 (t, J = 7.3 Hz, 2H), 1.94–1.87 (m, 3H), 1.76 (s, 3H), 1.69–1.53 (m, 6H), 1.51–1.38 (m, 13H), 1.26–1.20 (m, 9H), 0.84 (t, J = 7.4 Hz, 3H), 0.77 (t, J = 7.3 Hz, 3H). 13 C NMR (100 MHz, DMSO - d 6)δ172.7,172.3,165.9,138.9,129.0,81.6,75.6,60.9,54.2,47.7,35.8,34.1,30.8,29.0(d,J=4.2Hz),28.2,26.2,26.0,25.8,25.7,23.3,14.5,9.4.HRMS(ESI):[M+H] + calculated for C 36 H 60 N 3 O 6 :630.4482,found:630.4470.

[0086] Compound 5d - Methyl 9 - ((bicyclo[2.2.1]hept - 5 - en - 2 - ylmethyl)amino)-9 - oxononanoate: Starting from 9 - methoxy - 9 - oxononanoic acid (2.0 g, 9.9 mmol) and 5 - norbornene - 2 - methylamine (1.33 g, 10.89 mmol), light yellow solid 5d (1.38 g, 45.96%) was obtained.

[0087] Compound 6d - 9 - ((bicyclo[2.2.1]hept - 5 - en - 2 - ylmethyl)amino)-9 - oxononanoic acid: Light yellow oil 6d (1.06 g, 80.68%) was obtained.

[0088] Compound L15 - Ethyl (3R,4R,5R)-4 - acetamido - 5 - (9 - ((bicyclo[2.2.1]hept - 5 - en - 2 - ylmethyl)amino)-9 - oxononanamido)-3 - (pentan - 3 - yloxy)cyclohex - 1 - ene - 1 - carboxylate: Starting from 6d (0.5 g, 1.7 mmol) and oseltamivir (0.53 g, 1.64 mmol), white solid L15 (0.24 g, 41.73%) was obtained. 1 HNMR(600MHz,DMSO - d 6)δ 7.83 (dd, J = 9.3, 4.8 Hz, 1H), 7.72 (t, J = 5.7 Hz, 1H), 7.63 (t, J = 9.5 Hz, 1H), 6.63 (d, J = 2.5 Hz, 1H), 6.14 (dd, J = 5.7, 3.0 Hz, 1H), 5.94 (dd, J = 5.7, 2.8 Hz, 1H), 4.18–4.11 (m, 2H), 4.07 (dd, J = 7.3, 3.5 Hz, 1H), 3.94–3.87 (m, 1H), 3.77–3.71 (m, 1H), 3.40–3.36 (m, 1H), 2.82–2.78 (m, 1H), 2.75 (d, J = 11.1 Hz, 1H), 2.65–2.58 (m, 1H), 2.47 (dd, J = 17.5, 5.4 Hz, 1H), 2.24–2.13 (m, 2H), 2.08–1.95 (m, 4H), 1.76 (d, J = 2.4 Hz, 4H), 1.50–1.40 (m, 7H), 1.38–1.33 (m, 1H), 1.30 (dd, J = 8.1, 2.0 Hz, 1H), 1.27–1.17 (m, 11H), 1.15–1.07 (m, 1H), 0.84 (t, J = 7.4 Hz, 3H), 0.76 (t, J = 7.4 Hz, 3H). 13 C NMR (151 MHz, DMSO-d 6 )δ 171.2, 171.1, 168.7, 164.9, 137.8, 136.3, 135.9, 135.8, 131.9, 128.0, 80.5, 80.5, 74.6, 59.8, 53.2, 53.2, 48.3, 46.6, 44.0, 43.1, 43.1, 43.0, 41.9, 41.3, 40.6, 39.5, 38.2, 37.9, 35.1, 34.8, 33.0, 29.8, 29.2, 28.0, 28.0, 27.9, 27.8, 25.1, 24.8, 24.8, 24.7, 24.6, 23.9, 22.2, 20.5, 19.6, 13.5, 8.8, 8.4. HRMS (ESI): [M+Na] + calculated for C 33 H 53 N 3 O 6 Na: 610.3832, found: 610.3823.

[0089] Compound 5e - Methyl 10 - ((((3r,5r,7r)-adamantan-1-yl)methyl)amino)-10-oxodecanoate: Starting from 10-oxo-10-methoxydecanoic acid (2.0 g, 9.25 mmol) and 1-adamantanemethylamine (1.68 g, 10.18 mmol), light yellow solid 5e (1.67 g, 49.96%) was obtained.

[0090] Compound 6e - 10 - ((((3r,5r,7r)-adamantan-1-yl)methyl)amino)-10-oxodecanoic acid: Light yellow oil 6e (1.28 g, 79.68%) was obtained.

[0091] Compound L16 - Ethyl (3R,4R,5R)-4-acetamido-5-(10 - ((((3r,5r,7r)-adamantan-1-yl)methyl)amino)-10-oxodecanamido)-3-(pent-3-yloxy)cyclohex-1-ene-1-carboxylate: Starting from 6e (0.5 g, 1.43 mmol) and oseltamivir (0.49 g, 1.57 mmol), white solid L16 (0.42 g, 45.73%) was obtained. 1 HNMR(600MHz,DMSO-d 6 )δ7.83(dd,J=9.5,3.6Hz,1H),7.63(t,J=7.3Hz,1H),7.59(t,J=6.3Hz,1H),6.64(t,J=2.5Hz,1H),4.17–4.11(m,2H),4.09–4.06(m,1H),3.95–3.88(m,1H),3.78–3.72(m,1H),3.41–3.36(m,1H),3.33(s,2H),2.75(d,J=6.3Hz,2H),2.49–2.44(m,1H),2.23–2.16(m,1H),2.09(t,J=7.3Hz,2H),2.00–1.97(m,2H),1.93–1.89(m,3H),1.76(s,3H),1.65(d,J=12.0Hz,3H),1.57(d,J=11.7Hz,3H),1.48–1.40(m,12H),1.29–1.19(m,12H),0.84(t,J=7.4Hz,3H),0.77(t,J=7.4Hz,3H). 13 C NMR(151MHz,DMSO-d 6)δ172.7,172.3,169.8,138.9,129.0,81.6,75.6,60.9,54.2,50.4,47.7,40.3,37.0,36.2,35.9,34.1,30.8,29.3,29.1,29.1,28.2,26.2,26.0,25.9,25.7,23.2,14.5,9.9,9.4.HRMS(ESI):[M+H] + calculated for C 37 H 62 N 3 O 6 :644.4639,found:644.4629.

[0092] Compound 2e - tert-butyl (2-(2-(2-((((3r,5r,7r)-adamantan-1-yl)methyl)amino)-2-oxoethoxy)ethoxy)ethyl)carbamate: Starting from 8-tert-butoxycarbonylamino-3,6-dioxooctanoic acid (2.0 g, 7.6 mmol) and 1-adamantanemethylamine (1.68 g, 8.36 mmol), light yellow solid 2e (1.67 g, 53.69%) was obtained.

[0093] Compound 3e - N-((((3r,5r,7r)-adamantan-1-yl)methyl)-2-(2-(2-aminoethoxy)ethoxy)acetamide: Light yellow oil 3e (1.23 g, 97.68%) was obtained.

[0094] Compound L17 - ethyl (3R,4R,5R)-4-acetamido-5-(3-(2-(2-(2-((((3r,5r,7r)-adamantan-1-yl)methyl)amino)-2-oxoethoxy)ethoxy)ethyl)ureido)-3-(pent-3-yloxy)cyclohex-1-ene-1-carboxylate: Starting from oseltamivir (0.5 g, 1.6 mmol) and 3e (0.54 g, 1.76 mmol), white solid L17 (0.43 g, 41.73%) was obtained. 1 H NMR(600MHz,DMSO-d 6)δ 7.93 (d, J = 6.9 Hz, 1H), 7.51 (t, J = 6.3 Hz, 1H), 6.61 (s, 1H), 6.20 (s, 1H), 5.83 (d, J = 6.6 Hz, 1H), 4.16–4.03 (m, 3H), 3.90 (s, 2H), 3.73–3.66 (m, 2H), 3.61–3.52 (m, 4H), 3.39 (s, 3H), 3.16–3.09 (m, 2H), 2.81 (d, J = 6.2 Hz, 2H), 2.64–2.56 (m, 1H), 2.03 (dd, J = 17.8, 7.5 Hz, 1H), 1.89 (s, 3H), 1.78 (s, 3H), 1.63 (d, J = 11.9 Hz, 3H), 1.55 (d, J = 11.9 Hz, 3H), 1.48–1.31 (m, 10H), 1.24–1.21 (m, 3H), 0.82 (t, J = 7.3 Hz, 3H), 0.76 (t, J = 7.1 Hz, 3H). 13 C NMR (151 MHz, DMSO-d 6 ) δ 170.0, 169.8, 166.0, 158.3, 138.8, 129.1, 81.5, 75.7, 70.8, 70.6, 70.3, 69.8, 60.9, 54.2, 50.0, 48.6, 40.3, 37.0, 34.2, 32.0, 28.1, 26.2, 25.7, 23.3, 14.6, 9.9, 9.5. HRMS (ESI): [M + H] + calculated for C 34 H 57 N 4 O 8 : 649.4176, found: 649.4167.

[0095] Compound 2f - tert-Butyl (2-(2-(2-((bicyclo[2.2.1]hept-5-en-2-ylmethyl)amino)-2-oxoethoxy)ethoxy)ethyl)carbamate: Starting from 8-(tert-butoxycarbonylamino)-3,6-dioxooctanoic acid (2.0 g, 7.6 mmol) and 5-norbornene-2-methylamine (1.02 g, 8.36 mmol), light yellow solid 2f (1.55 g, 55.69%) was obtained.

[0096] Compound 3f - Starting from 8-(tert-butoxycarbonylamino)-3,6-dioxooctanoic acid (2.0 g, 7.6 mmol) and 5-norbornene-2-methylamine (1.02 g, 8.36 mmol), light yellow solid 2f (1.55 g, 55.69%) was obtained.: Light yellow oil 3f (1.06 g, 93.78%) was obtained.

[0097] Compound L18 - Ethyl (3R,4R,5R)-4-acetamido-5-[3-(2-(2-(2-((bicyclo[2.2.1]hept-5-en-2-ylmethyl)amino)-2-oxoethoxy)ethoxy)ethyl)carbamoyl]-3-(pentan-3-yloxy)cyclohex-1-ene-1-carboxylate: Starting from oseltamivir (0.5 g, 1.86 mmol) and 3f (0.55 g, 2.05 mmol), white solid L18 (0.55 g, 49.43%) was obtained. 1 H NMR(600MHz,DMSO-d 6 )δ7.84(d,J=8.2Hz,1H),6.63(s,1H),6.14(t,J=5.6Hz,1H),5.79(d,J=7.4Hz,1H),4.16–4.09(m,J=10.9,4.9Hz,2H),4.08–3.97(m,2H),3.86(d,J=5.3Hz,2H),3.79–3.69(m,2H),3.55(dd,J=9.7,4.8Hz,4H),3.43–3.29(m,4H),3.13(h,J=7.4Hz,2H),2.61(dd,J=17.2,4.2Hz,1H),2.31–2.24(m,1H),2.20(t,J=3.9Hz,1H),2.08–1.94(m,2H),1.83–1.66(m,5H),1.53(dd,J=11.9,5.4Hz,1H),1.49–1.31(m,6H),1.22(t,J=7.0Hz,4H),0.83(t,J=7.6Hz,4H),0.77(t,J=7.3Hz,3H). 13 C NMR(151MHz,DMSO-d 6)δ170.0,169.6,169.4,166.0,158.3,138.8,129.1,81.6,81.5,75.9,75.8,70.7,70.7,70.5,70.4,70.4,69.8,62.8,62.5,60.9,54.2,53.9,48.8,48.6,48.6,46.6,46.2,43.6,42.9,42.8,40.8,39.7,39.2,38.9,38.4,36.9,36.5,34.7,33.6,32.1,32.0,31.8,31.5,29.0,26.8,26.2,26.1,25.7,25.7,25.3,23.3,23.3,23.0,21.1,19.7,14.5,11.7,9.9,9.5.HRMS(ESI):[M+Na] + calculated for C 31 H 50 N 4 O 8 :629.3526,found:629.3513.

[0098] Compound 2g - tert - butyl (2-(2-(2-(((1r,3R,5S,7r)-3,5-dimethyladamantan-1-yl)amino)-2-oxoethoxy)ethoxy)ethyl)carbamate: Starting from 8 - tert - butoxycarbonylamino - 3,6 - dioxooctanoic acid (2.0 g, 7.6 mmol) and memantine (1.49 g, 8.36 mmol), a light yellow solid 2g (1.94 g, 60.29%) was obtained.

[0099] Compound 3g - 2-(2-(2 - aminoethoxy)ethoxy)-N-((1r,3R,5S,7r)-3,5 - dimethyladamantan-1-yl)acetamide: A light yellow oil 3g (1.44 g, 97.28%) was obtained.

[0100] Compound L19 - ethyl (3R,4R,5R)-4 - acetamido - 5-(3-(2-(2-(2-(((1r,3R,5S,7r)-3,5 - dimethyladamantan-1-yl)amino)-2 - oxoethoxy)ethoxy)ethyl)ureido)-3-(pentan - 3 - yloxy)cyclohex - 1 - ene - 1 - carboxylate: Starting from oseltamivir (0.5 g, 1.86 mmol) and 3g (0.66 g, 2.05 mmol), a white solid L19 (0.56 g, 45.73%) was obtained. 1 H NMR(600MHz,DMSO - d 6)δ 7.81 (d, J = 8.5 Hz, 1H), 6.87 (s, 1H), 6.64 (t, J = 2.6 Hz, 1H), 6.12 (t, J = 5.7 Hz, 1H), 5.81 (d, J = 7.9 Hz, 1H), 4.17–4.10 (m, 2H), 4.05–4.02 (m, 1H), 3.76 (s, 2H), 3.75–3.70 (m, 2H), 3.57–3.50 (m, 4H), 3.42–3.36 (m, 3H), 3.19–3.09 (m, 2H), 2.62 (dd, J = 16.8, 4.0 Hz, 1H), 2.06–2.01 (m, 1H), 1.79 (d, J = 6.3 Hz, 5H), 1.62 (d, J = 11.7 Hz, 2H), 1.57 (d, J = 11.8 Hz, 2H), 1.45–1.40 (m, 2H), 1.34–1.30 (m, 2H), 1.27–1.20 (m, 6H), 1.11 (d, J = 2.4 Hz, 2H), 0.87–0.80 (m, 9H), 0.78 (t, J = 7.4 Hz, 3H). 13 C NMR (151 MHz, DMSO-d 6 )δ 169.9, 168.7, 166.0, 158.2, 138.8, 129.1, 81.6, 75.8, 70.7, 70.6, 70.4, 69.7, 60.9, 54.2, 52.7, 50.6, 48.6, 47.5, 42.7, 40.5, 39.9, 32.3, 32.1, 30.4, 30.0, 29.1, 27.0, 26.2, 25.7, 25.0, 23.3, 22.6, 14.5, 14.4, 9.9, 9.5. ESI-MS: m / z 606.36 HRMS(ESI): [M + H] + calculated for C 35 H 59 N 4 O 8 : 663.4333, found: 663.4322.

[0101] The specific structures of compounds L1 - L19 are as follows:

[0102]

[0103]

[0104] Example 2

[0105] In vitro anti-influenza virus assay in MDCK cells:

[0106] The anti-influenza virus activity of the compound was evaluated by infecting MDCK cells with influenza A virus H1N1 (A / Puerto Rico / 8 / 1934, containing NA-H274Y, where NA-H274Y refers to a specific mutation in the neuraminidase (NA) gene, specifically, histidine (His, H) at position 274 is replaced by tyrosine (Tyr, Y)). MDCK cells (2.5×10^4 cells / well) were added to a 96-well plate and incubated overnight at 37°C and 5% CO 2 2. Then, the cells were infected with influenza virus at a 50% tissue culture infective dose (TCID50) for 1 hour. After discarding the virus solution, gradient dilutions of the compound were added and incubation continued for 48 hours. After incubation, 100 μL of Cell Counting Kit-8 (CCK-8, Dojindo Molecular Technologies) reagent solution (consisting of 90 μL of medium and 10 μL of CCK-8) was added to each well. After incubation at 37°C for 90 minutes, the absorbance was read at 450 nm using a microplate reader. By using GraphPad Prism6 software, a curve fitting the percentage of cytopathic effect (CPE) and the concentration of the NA inhibitor was used to determine the EC 50 50 value. The determination method of the CC 50 50 value was the same as that of the EC50, but without virus infection. The entire assay was performed in a BSL-2 facility. The test results are shown in Table 1, where NA indicates inactivity, the EC 50 50 value represents the concentration of the compound that inhibits 50% of plaque formation, and the CC 50 50 value represents the concentration of the compound that causes a 50% reduction in cell viability.

[0107] Table 1 Anti-H1N1-H274Y virus activity and cytotoxicity of each compound in MDCK cells

[0108]

[0109]

[0110] The H274Y mutation significantly reduces the efficacy of oseltamivir, causing difficulties in clinical treatment. Therefore, we studied the antiviral activities of compounds L1-L19 against the oseltamivir-resistant H1N1-H274Y virus strain using oseltamivir (OSP) as a control in MDCK cells. As shown in Table 1, compounds L1-L6 introduced various hydrophobic tags through amide bonds or urea bonds, but showed limited activity against the H1N1-H274Y virus strain. To enhance the antiviral activity and extend the carbon chain length connecting oseltamivir and the hydrophobic tag, alkyl chain-linked compounds L7-L16 were synthesized. These compounds exhibited significant antiviral potency, and derivatives with adamantane tags showed superior activity to oseltamivir; in particular, compound L12, which was linked to the hydrophobic tag through a nine-carbon chain, showed 157-fold stronger potency than oseltamivir, with an EC 50 of 0.68 μM; L14 was also linked to the hydrophobic tag through a nine-carbon chain and showed 57-fold stronger potency compared to oseltamivir, with an EC 50 of 1.87 μM; indicating that the chain length of the linker has a crucial impact on antiviral activity. In addition, memantine was used as a hydrophobic tag for the first time in this application, showing effective resistance reversal activity in compounds L10, L11, and L19. In addition, the PEG linker (HO-C-C-OH) was incorporated into compounds L17-L19 as part of the linker structure and also showed excellent antiviral activity. Cytotoxicity tests performed by the CCK-8 method showed that no significant cytotoxicity was found for all tested compounds at concentrations up to 50 μM.

[0111] Example 3

[0112] The degradation activity of the compounds against influenza virus neuraminidase (NA) protein was evaluated by Western blot analysis. A recombinant plasmid containing the full-length NA fragment with a Flag tag was transfected into 293T cells. The 293T cells were seeded in 6-well plates at a density of 6×10 5 cells / well and incubated at 37 °C in 5% CO 2Cultivate for 12 hours under the conditions. Subsequently, 1 μg of plasmid DNA was transfected into the cells. After 8 hours, the medium was replaced with fresh medium, and the compound was added and incubated for 24 hours, with DMSO as the solvent control. Subsequently, the NA protein level was evaluated by Western blot: The 293T cells were washed twice with pre-cooled PBS, and then lysed on ice with RIPA lysis buffer containing protease inhibitor mixture for 15 minutes. The lysate was centrifuged at 15,000 g for 30 minutes at 4 °C, and the supernatant was collected for protein quantification by BCA method. After separation by 4-12% SDS-PAGE, the protein samples were transferred to PVDF membranes. The membranes were blocked with PBST containing 5% non-fat milk powder at room temperature for 1 hour, and then incubated with the primary antibody overnight at 4 °C. The dilution ratios of the primary antibodies were as follows: Flag (1:1000, Proteintech), GAPDH (1:1000, Cell Signaling Technology). After washing with PBST, the membranes were incubated with the HRP-conjugated secondary antibody for 1 hour, and then washed with PBST again. The NcmECLUltra chemiluminescent substrate kit was used to visualize the bands. Chemiluminescence-based blots were captured by the iBright 1500 imaging system (Invitrogen) and analyzed with Image J software. Figure 1 It is a result graph of the degradation activity of NA protein in 293T cells treated with different compounds involved in Example 2 of the present application. Figure 1 In the bar graph, the ordinate is the multiple of the degradation activity of NA protein, and the multiple of the degradation activity of the DSMO group is 1. As Figure 1 shown, HyTTDs mainly exerts its antiviral effect by degrading NA protein. At a concentration of 10 μM, compounds L7, L8, L10, L12, L14, and L17 showed significant degradation activity against NA protein. Among them, L12 showed the most significant degradation effect, which was consistent with its strong antiviral activity against H1N1-H274Y virus in vitro.

[0113] Example 4

[0114] To confirm the strong NA degradation and antiviral effects of the compounds on the H1N1-H274Y virus strain, immunofluorescence analysis was performed on compounds L12 and L14 to evaluate their antiviral activity in vitro. MDCK cells (2×10^4 cells / well) were seeded in 96-well plates and incubated at 37 °C, 5% CO 2Incubate overnight under the conditions. MDCK cells were infected with the virus at a multiplicity of infection (MOI) of 0.1 for 1 hour. Subsequently, the virus was discarded, and the cells were incubated with the corresponding concentration of the compound for 24 hours. Then, the cells were fixed with 4% paraformaldehyde at room temperature for 20 minutes and then blocked with 10% BSA for 1 hour. Subsequently, the cells were incubated overnight at 4 °C with an influenza virus nucleoprotein (NP) antibody (GeneTex, GTX1236). Next, the cells were incubated with an FITC-labeled secondary antibody for 1 hour (Santa Cruz, CA, USA). DAPI nuclear dye was added and stained for 5 minutes. Fluorescence was observed using a fluorescence microscope (Nikon, Japan). The cells were treated with OSP (100 μM) or the test compound at concentrations of 2.5 μM, 5 μM, and 10 μM for 24 hours. Figure 2 is the result graph of the NP protein expression of MDCK cells treated with different compounds involved in Example 4 of this application. As Figure 2 shown, compounds L12 and L14 showed dose-dependent inhibition of viral nucleoprotein (NP) expression. Compared with oseltamivir at a concentration of 100 μM, compounds L12 and L14 showed significantly enhanced inhibitory effects, further confirming their effectiveness against oseltamivir-resistant influenza.

[0115] Example 5

[0116] To study the binding mode of these compounds to neuraminidase (NA), molecular docking studies were performed using Schrodinger software Maestro (PDB: 3CL0

[29] ). The molecular docking studies were carried out using Maestro of Schrodinger Software. The crystal structure of the H274Y-NA of the H5N1 strain, the complex bound to the ligand oseltamivir (PDB ID: 3CL0), was obtained from the Protein Data Bank. First, the protonation state of the complex was adjusted to be consistent with pH 7.4. The structure of the endonuclease was preprocessed, including adding missing hydrogen atoms, bond assignment, generation of amino acid residue states, removing water molecules, and optimizing hydrogen bonds. Then, a grid file containing oseltamivir was created through receptor grid generation. Finally, grid docking was performed to evaluate the binding energy and predict the mode of action of the compound, and mapping was carried out using PyMOL. Figure 3 is the molecular docking result graph involved in Example 5 of this application, showing the binding mode of L12 and L14 to the H274Y mutant using the H5N1 structure (PDB: 3CL0). Among them, the H5N1 protein is presented in white cartoon form, oseltamivir is shown as a green stick model, and hydrogen bonds are represented by dotted lines. Figure 3 In it, part A is the surface view of L12; part B is the surface view of L14; part C is the 3D representation of L12; part D is the 3D representation of L14. As Figure 3As shown, the oseltamivir moieties of compounds L12 and L14 occupy the active pocket of the NA protein, while the extended part of the HyT side chain at the amino group enters the region of the protein exposed to the solvent. This modification enhances the hydrophobicity of the protein surface, mimics misfolding, and promotes degradation. Compounds L12 and L14 have a similar binding mode to the NA protein, where the oxygen atom in the ether bond acts as a hydrogen bond acceptor and forms a hydrogen bond with Asn294. The side chain ester group interacts with the hydrophilic pocket formed by Arg118, Arg371, and Arg292, while the side chain amide establishes a hydrogen bond with Arg152.

[0117] Example 6

[0118] Pharmacokinetic study of L12:

[0119] Considering that compound L12 has a significant inhibitory effect on influenza virus proliferation in vitro and can degrade NA, this application further evaluated its pharmacokinetic (PK) properties. Three CD-1 mice were tested by intravenous injection at a dose of 1.5 mg / kg, with three mice in each group (n = 3). At the start of the experiment, 1.85 mg of the test compound L12 was placed in a 5 mL glass vial, and 0.352 mL of dimethyl sulfoxide (DMSO) was added to dissolve it, preparing a stock solution of 5 mg / mL. Subsequently, 0.342 mL of this stock solution was mixed with 1.026 mL of Solutol, dissolved by stirring, and then 5.472 mL of normal saline was added to ensure uniform distribution. Using ultrasonic and shaking techniques, a colorless and transparent solution was obtained, and finally, an intravenous injection preparation of 0.25 mg / mL was prepared. Plasma samples were collected at multiple time points after administration: 5 minutes, 15 minutes, 30 minutes, 1 hour, 2 hours, 4 hours, 8 hours, and 24 hours. Blood was collected using EDTA-K2 anticoagulant tubes and left to stand on wet ice for at least 15 minutes. Plasma samples were separated by centrifugation at 6000 rpm for 3 minutes at 2 - 8°C. Sample analysis was performed using liquid chromatography - tandem mass spectrometry (LC-MS / MS), and pharmacokinetic parameters were calculated using WinNonlin 8.2 software. Key parameters are summarized in Table 2, which shows the pharmacokinetic parameters calculated after a single intravenous injection (dose of 1.5 mg / kg) of L12 in CD-1 mice. The results are shown as mean ± standard deviation (SD), n = 3. According to Table 2, after a single intravenous injection, L12 reached a maximum plasma concentration (Cmax) of 5910 ng / mL at 4.9 minutes, with a half-life of 0.246 hours and a clearance rate of 939 mL / hr / kg. These moderate pharmacokinetic parameters indicate that this lead compound has the potential to improve its bioavailability through further optimization.

[0120] Table 2 Pharmacokinetics of compound L12 after intravenous injection in CD-1 mice

[0121]

[0122]

[0123] In this application, a series of oseltamivir-based HyTTDs were screened and their activities against the oseltamivir-resistant H1N1-H274Y strain were evaluated. Most of the compounds showed significant activity at submicromolar concentrations, and among them, compounds L12 and L14 showed the strongest effects, with EC 50 values of 0.68 μM and 1.87 μM, respectively, which were significantly better than oseltamivir. Western blot experiments confirmed that these compounds could induce the degradation of NA protein. Immunofluorescence studies further revealed a dose-dependent inhibition of viral nucleoprotein (NP) expression, confirming its mechanism of action by targeting protein degradation. L12 exhibited moderate pharmacokinetic properties.

[0124] The above content is a further detailed description of this application in combination with specific implementation manners, and it cannot be determined that the specific implementation of this application is only limited to these descriptions. For those of ordinary skill in the technical field to which this application belongs, without departing from the concept of this application, several simple deductions or substitutions can still be made.

Claims

1. A neuraminidase inhibitor based on hydrophobic tag technology, characterized in that: The structure is shown in formula (I): Linker is selected from the following structures: n is a natural number between 2 and 10, m is 0 or 1, k is a natural number between 0 and 10, h is a natural number between 0 and 10, and s is a natural number between 1 and 5; HyT was selected from the following structures:

2. The neuraminidase inhibitor according to claim 1, characterized in that n is a natural number between 6 and 9; Preferably, k is a natural number between 1 and 4; Preferably, h is a natural number between 1 and 4; Preferably, s is a natural number between 1 and 4; Preferably, s is 1.

3. The neuraminidase inhibitor according to claim 1, characterized in that HyT was selected from the following structures:

4. The neuraminidase inhibitor according to claim 1, characterized in that The neuraminidase inhibitor includes at least one of the following compounds L7 to L19:

5. A derivative of the neuraminidase inhibitor according to any one of claims 1 to 4, including a pharmaceutically acceptable salt, stereoisomer, ester, prodrug, solvate or deuterated compound.

6. A method for preparing a neuraminidase inhibitor based on hydrophobic tag technology, characterized in that: include: and HyT-NH2 under the condition of adding HATU and DIPEA to react; then adding hydrochloric acid to react to remove the Boc protecting group; then reacting with oseltamivir under the condition of adding TEA, CDI and DMF to obtain the neuraminidase inhibitor; or, and HyT-NH2 under the condition of adding HATU and DIPEA, reacting; then adding lithium hydroxide and water, reacting at 50° C.; then reacting with oseltamivir under the condition of adding HATU and DIPEA, to obtain the neuraminidase inhibitor; Wherein, n is a natural number between 2 and 10, k is a natural number between 0 and 10, h is a natural number between 0 and 10, s is a natural number between 1 and 5, and HyT is selected from the following structures:

7. A pharmaceutical composition, characterized in that The invention comprises the neuraminidase inhibitor according to any one of claims 1 to 4 or the derivative according to claim 5, and one or more pharmaceutically acceptable excipients.

8. Use of the neuraminidase inhibitor according to any one of claims 1 to 4 or the pharmaceutical composition according to claim 7 in the preparation of a medicament for treating and / or preventing diseases related to influenza virus infection.

9. Use of the neuraminidase inhibitor according to any one of claims 1 to 4 or the pharmaceutical composition according to claim 7 in the preparation of a medicament for treating oseltamivir resistance-related diseases.

10. Use of the neuraminidase inhibitor according to any one of claims 1 to 4 or the pharmaceutical composition according to claim 7 in the preparation of a medicament for inhibiting the activity of influenza A virus carrying the H274Y mutation, wherein the influenza A virus includes at least one of H1N1 and H5N1.

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