Integrin ligand and use thereof

Abstract

The present invention provides a compound as represented by the following formula I, a tautomer thereof, or a pharmaceutically acceptable salt thereof. The compound has serum stability and affinity for integrin αvβ6, has a good inhibitory effect on the integrin αvβ6, and thus has an inhibitory effect on tumor growth.

Description

Integrin ligand and use thereof Technical Field

[0001] The present invention belongs to the field of biomedicine, and in particular relates to an integrin ligand and its use. Background Art

[0002] Cancer is a major cause of death from disease. Studies have shown that the tumor microenvironment plays a crucial role in the development and metastasis of tumor cells. Among these, the adhesion molecule family plays a key role in the tumor microenvironment. Integrins are a type of surface cell adhesion molecule, consisting of 24 different integrins, composed of 18 α-subunits and 8 β-subunits. Integrin αvβ6 is an αvβ6 heterodimer formed by the binding of integrin αv and integrin β6. Its main structure consists of three domains: a cytoplasmic domain, an extracellular domain, and a transmembrane domain. Existing studies have shown that αvβ6 integrin can promote cell invasion and migration during metastasis and inhibit apoptosis. αvβ6 integrin can also regulate the expression of matrix metalloproteinases (MMPs) and activate TGF-β1. Accumulating evidence from in vitro studies suggests that αvβ6 integrin may promote cancer progression. Therefore, considering the role of integrin αvβ6 in matrix metalloproteinase (MMP) expression and TGF-β1 activation, integrin αvβ6 is attractive as a tumor biomarker and potential therapeutic target.

[0003] The in vivo delivery of therapeutically effective compounds, such as drug compounds, to desired cells and / or tissues remains a challenge in drug product development. Currently, in the field of drug delivery, there remains a need for stable and effective targeting ligands that can selectively target cells or tissues, which can be used to facilitate the targeted delivery of transported molecules (e.g., therapeutically active compounds or ingredients) to specific cells or tissues. Indeed, in the drug development process, there is a general need for targeting ligands that can be conjugated to one or more selected transported molecules (e.g., one or more drug products or other payloads) to facilitate the delivery of the transported molecules to desired cells or tissues in vivo. In addition, there is a need for compounds that target integrin αvβ6 that are suitable for conjugation to transported molecules to deliver the transported molecules to cells expressing integrin αvβ6 in vivo. For certain transported molecules, such as therapeutic oligonucleotide-based compounds (e.g., antisense oligonucleotides or RNAi agents), a targeting ligand capable of targeting integrin αvβ6 is required, which can be conjugated to the oligonucleotide-based compound to deliver the therapeutic agent to cells and / or tissues expressing integrin αvβ6 and promote the entry of the therapeutic agent into the cell by receptor-mediated endocytosis, pinocytosis or other means.

[0004] Chinese patent CN201880070813.4 discloses an αvβ6 integrin ligand having serum stability and affinity for integrin αvβ6. The αvβ6 integrin ligand can be used to target cells expressing integrin αvβ6 in vitro, in situ, ex vivo, and / or in vivo. It comprises the structure:

[0005] Chinese patent CN201980028704.0 discloses an integrin targeting ligand having serum stability and affinity for αvβ3 integrin and / or αvβ5 integrin, and suitable for conjugation to a transported molecule, such as an oligonucleotide-based therapeutic agent (e.g., an RNAi agent), to facilitate delivery of the transported molecule to cells and tissues, such as tumor cells, which express integrin αvβ3, integrin αvβ5, or both integrin αvβ3 and integrin αvβ5, comprising the structure:

[0006] Currently, research on integrins as targeting ligands is still very scarce. The development of new integrin ligands is of great value and significance for drug delivery and disease treatment.

[0007] Summary of the Invention

[0008] The present invention overcomes the shortcomings of the prior art by providing a synthetic αvβ6 integrin ligand with excellent serum stability and affinity for integrin αvβ6, specifically exhibiting superior targeting and inhibitory effects. The ligand can be used to deliver transported molecules, such as RNAi agents or other oligonucleotide-based compounds, to cells expressing integrin αvβ6, thereby promoting the uptake of the transported molecules into these cells, thereby achieving excellent pharmacodynamic activity.

[0009] The present invention provides a compound represented by the following formula I, its tautomers or pharmaceutically acceptable salts thereof, which is:

[0010] in,

[0011] Ring A is selected from optionally substituted C 3-10 Cycloalkyl, 3-10 membered heterocycloalkyl and phenyl;

[0012] n is an integer from 0 to 7;

[0013] J is selected from CH or N;

[0014] X is selected from -CH2-, -C(=O)-;

[0015] Y is selected from -CH2-, -C(=O)-;

[0016] Z is selected from OR6, N(R6)2 or SR6;

[0017] R1 is selected from H, optionally substituted alkyl;

[0018] R2 is selected from H, optionally substituted alkyl;

[0019] R3 is selected from aryl optionally substituted by R7, optionally substituted heteroaryl, optionally substituted heterocyclyl, optionally substituted cycloalkyl or R3 comprises a transported molecule;

[0020] R4 is selected from H, C 1-3 alkyl;

[0021] R5 is selected from H, C 1-3 alkyl;

[0022] Each R6 is independently selected from H, optionally substituted alkyl, or R6 comprises a transported molecule;

[0023] Among them, ring A, R 1、 The substituents in R2 and R6 are independently selected from halogen, CF3, OH, NH2, C 1-6 Alkoxy, the number of substituents in each group is independently selected from 1, 2 or 3;

[0024] R7 is selected from one or more divalent cyclic moieties having 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 carbon atoms optionally substituted with R8, wherein R8 comprises one or more molecules to be transported.

[0025] In some embodiments of the present invention, the above n is 3, X is selected from -CH2-, Y is selected from -CH2-, and Z is selected from OH.

[0026] In some embodiments of the present invention, n is 3, X is selected from -C(=O)-, Y is selected from -C(=O)-, and Z is OH.

[0027] In some embodiments of the present invention, the above R1 is selected from R2 is selected from H, R3 is selected from phenyl, R4 is selected from H, and R5 is selected from H.

[0028] In some embodiments of the present invention, R1 is selected from H, R2 is selected from H, R3 is selected from phenyl, R4 is selected from H, and R5 is selected from H.

[0029] In some embodiments of the present invention, R1 is selected from H, R2 is selected from H, R3 is selected from phenyl, R4 is selected from methyl, and R5 is selected from methyl.

[0030] In some embodiments of the present invention, the ring A is selected from

[0031] In some embodiments of the present invention, the above-mentioned J is selected from N.

[0032] In some embodiments of the present invention, the above-mentioned divalent cyclic portion includes a cycloalkyl group, a cycloalkenyl group, an aryl group, a heteroaryl group or a heterocyclic group, the cycloalkyl group is a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group or a cycloheptyl group, the cycloalkenyl group is a cyclopentenyl group, a cyclobutenyl group, a cyclopentenyl group, a cyclohexenyl group or a cycloheptenyl group, the aryl group is a phenyl group or a naphthyl group, the heteroaryl group is a pyridyl group, a pyrimidinyl group, a pyridazinyl group, a pyrrole group, a pyrazole group, an imidazole group, a thiophene group, a benzothiophene group, a thiazole group, a benzothiazole group, a furan group, an oxazole group, an isoxazole group, a benzofuran group, an indole group, an indazole group, a benzimidazole group, an oxadiazole group, a 1,2,3-triazole group, a 1,2,4-triazole group, a tetrazole group, a quinolyl group, an isoquinolyl group or a quinoxalinyl group, and the heterocyclic group is a tetrahydrofuran group, a tetrahydropyran group, a piperidine group, a pyrrolidine group, a dioxane group or a dioxolane group.

[0033] The present invention provides a compound of the following formula, a tautomer thereof or a pharmaceutically acceptable salt thereof,

[0034] Therein, R9 comprises the molecule being transported (eg, an RNAi agent).

[0035] In some embodiments of the present invention, the compound further comprises a polyethylene glycol linker having 2-20 ethylene oxide units. The polyethylene glycol linker having ethylene oxide units can be linked to the compound and then to the molecule to be transported.

[0036] In another aspect, the present invention provides a compound of the following formula, a tautomer thereof or a pharmaceutically acceptable salt thereof, wherein the compound is selected from

[0037] in The point of attachment to the portion comprising the transported molecule is indicated.

[0038] In another aspect, the present invention provides a compound of the following formula, a tautomer thereof or a pharmaceutically acceptable salt thereof, wherein the compound is selected from

[0039] in The point of attachment to the portion comprising the transported molecule is indicated.

[0040] In some embodiments, the αvβ6 integrin ligand of Structures I-1a, I-2a, I-3a, II-1a, II-2a, and II-3a is linked to one or more transported molecules (e.g., one or more RNAi agents).

[0041] In some embodiments of the present invention, the transported molecule is an active pharmaceutical ingredient or a prodrug.

[0042] In some embodiments of the present invention, the transported molecules include small molecules, antibodies, antibody fragments, immunoglobulins, monoclonal antibodies, labels or markers, lipids, natural or modified nucleic acids, natural or modified nucleic acid oligonucleotides, natural or modified nucleic acid polynucleotides, peptides, nucleic acid aptamers, polymers, polyamines, proteins, toxins, vitamins, polyethylene glycol, haptens, digoxigenin, biotin, radioactive atoms or molecules, or fluorophores.

[0043] In some embodiments of the present invention, the transported molecule comprises an RNAi agent.

[0044] In another aspect, the present invention provides a structure comprising a compound, a linker, and a scaffold, wherein the structure binds to a molecule to be transported, wherein the compound is an αvβ6 ligand. In some embodiments of the present invention, the structure comprises a monodentate form of the αvβ6 integrin ligand.

[0045] In some embodiments of the present invention, the structure comprises a bidentate αvβ6 integrin ligand.

[0046] In some embodiments of the present invention, the structure comprises a tridentate αvβ6 integrin ligand.

[0047] In some embodiments of the present invention, the structure comprises a tetradentate αvβ6 integrin ligand.

[0048] As disclosed herein, in some embodiments, one or more αvβ6 integrin ligands may be linked to one or more transported molecules. In some embodiments, only one αvβ6 integrin ligand is conjugated to the transported molecule (referred to herein as a "monodentate" or "monovalent" ligand). In some embodiments, two αvβ6 integrin ligands are conjugated to the transported molecule (referred to herein as a "bidentate" or "bivalent" ligand). In some embodiments, three αvβ6 integrin ligands are conjugated to the transported molecule (referred to herein as a "tridentate" or "trivalent" ligand). In some embodiments, four αvβ6 integrin ligands are conjugated to the transported molecule (referred to herein as a "tetradentate" or "tetravalent" ligand). In some embodiments, more than four αvβ6 integrin ligands are conjugated to the transported molecule.

[0049] In some embodiments, when only one αβ integrin ligand is conjugated to the transported molecule (referred to herein as a "monodentate" ligand), the αβ integrin ligand can be conjugated directly to the transported molecule. In some embodiments, the αβ integrin ligands disclosed herein can be conjugated to the transported molecule via a scaffold or other linker structure.

[0050] In some embodiments, the αvβ6 integrin ligands disclosed herein include one or more scaffolds. Scaffolds, sometimes also referred to in the art as linking groups or linkers, can be used to facilitate the attachment of one or more transported molecules to one or more αvβ6 integrin ligands disclosed herein. Useful scaffolds compatible with the ligands disclosed herein are generally known in the art. Non-limiting examples of scaffolds that can be used with the αvβ6 integrin ligands disclosed herein include, but are not limited to, polymers and polyamino acids (e.g., diglutamic acid, poly-L-lysine, etc.). In some embodiments, the scaffold can include a cysteine ​​linker or group, DBCO-PEG1-24-NHS, propargyl-PEG1-24-NHS and / or a multidentate DBCO and / or propargyl moiety. In some embodiments of the present invention, the scaffold has the following formula:

[0051] in "" represents the RNAi agent, and "αvβ6 ligand" represents the respective ligand structure and linker.

[0052] In some embodiments of the present invention, the αvβ6 integrin ligand disclosed herein includes a tridentate structure of a glutaryl linker and can be represented by the following structure:

[0053] In some embodiments of the present invention, the αvβ6 integrin ligand disclosed herein includes a tridentate structure of a glutaryl linker and can be represented by the following structure:

[0054] In some embodiments of the present invention, the αvβ6 integrin ligand disclosed herein comprises a tridentate structure of a glutaryl linker and can be represented by the following structure:

[0055] In some embodiments, the αvβ6 integrin ligand disclosed herein comprises a tridentate structure conjugated to a RNAi agent and can be represented by the following structure:

[0056] in represents RNAi agent, X=O,S.

[0057] In some embodiments, the αvβ6 integrin ligand disclosed herein comprises a tridentate structure conjugated to a RNAi agent and can be represented by the following structure:

[0058] in represents RNAi agent, X=O,S.

[0059] In some embodiments, the αvβ6 integrin ligand disclosed herein comprises a tridentate structure conjugated to a RNAi agent and can be represented by the following structure:

[0060] in represents RNAi agent, X=O,S.

[0061] In some embodiments, the αvβ6 integrin ligand disclosed herein comprises a tridentate structure conjugated to a RNAi agent and can be represented by the following structure:

[0062] in represents RNAi agent, X=O,S.

[0063] In some embodiments, the αvβ6 integrin ligand disclosed herein comprises a tridentate structure conjugated to a RNAi agent and can be represented by the following structure:

[0064] in represents RNAi agent, X=O,S.

[0065] In another aspect, the present invention provides a compound represented by the following formula Ib, a tautomer thereof, or a pharmaceutically acceptable salt thereof, wherein the compound is an αvβ6 integrin ligand precursor comprising the structure:

[0066] in,

[0067] Ring A is selected from optionally substituted C 3-10 Cycloalkyl, 3-10 membered heterocycloalkyl and phenyl;

[0068] n is an integer from 0 to 7;

[0069] J is selected from CH or N;

[0070] X is selected from -CH2-, -C(=O)-;

[0071] Y is selected from -CH2-, -C(=O)-;

[0072] Z is selected from OR6, N(R6)2 or SR6;

[0073] R1 is selected from H, optionally substituted alkyl;

[0074] R2 is selected from H, optionally substituted alkyl;

[0075] R3 is selected from aryl optionally substituted by R7, optionally substituted heteroaryl, optionally substituted heterocyclyl, optionally substituted cycloalkyl, or R3 comprises a linker conjugated to a reactive group;

[0076] R4 is selected from H, C 1-3 alkyl;

[0077] R5 is selected from H, C 1-3 alkyl;

[0078] Each R6 is independently H, optionally substituted alkyl, or R6 comprises a linker group that is transported or conjugated to a reactive group;

[0079] Wherein, the substituents in ring A, R1, R2 and R6 are independently selected from halogen, CF3, OH, NH2, C 1-6 Alkoxy, the number of substituents in each group is independently selected from 1, 2 or 3;

[0080] R7 is selected from one or more divalent cyclic moieties having 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 carbon atoms optionally substituted with R8, wherein R8 comprises a linking group conjugated to a reactive group.

[0081] In some embodiments of the present invention, the above n is 3, X is selected from -CH2-, Y is selected from -CH2-, and Z is selected from OH.

[0082] In some embodiments of the present invention, n is 3, X is selected from -C(=O)-, Y is selected from -C(=O)-, and Z is OH.

[0083] In some embodiments of the present invention, the above R1 is selected from R2 is selected from H, R3 is selected from phenyl, R4 is selected from H, and R5 is selected from H.

[0084] In some embodiments of the present invention, R1 is selected from H, R2 is selected from H, R3 is selected from phenyl, R4 is selected from H, and R5 is selected from H.

[0085] In some embodiments of the present invention, R1 is selected from H, R2 is selected from H, R3 is selected from phenyl, R4 is selected from methyl, and R5 is selected from methyl.

[0086] In some embodiments of the present invention, the ring A is selected from

[0087] In some embodiments of the present invention, the above-mentioned J is selected from N.

[0088] In some embodiments of the present invention, the above-mentioned divalent cyclic portion includes a cycloalkyl group, a cycloalkenyl group, an aryl group, a heteroaryl group or a heterocyclic group, the cycloalkyl group is a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group or a cycloheptyl group, the cycloalkenyl group is a cyclopentenyl group, a cyclobutenyl group, a cyclopentenyl group, a cyclohexenyl group or a cycloheptenyl group, the aryl group is a phenyl group or a naphthyl group, the heteroaryl group is a pyridyl group, a pyrimidinyl group, a pyridazinyl group, a pyrrole group, a pyrazole group, an imidazole group, a thiophene group, a benzothiophene group, a thiazole group, a benzothiazole group, a furan group, an oxazole group, an isoxazole group, a benzofuran group, an indole group, an indazole group, a benzimidazole group, an oxadiazole group, a 1,2,3-triazole group, a 1,2,4-triazole group, a tetrazole group, a quinolyl group, an isoquinolyl group or a quinoxalinyl group, and the heterocyclic group is a tetrahydrofuran group, a tetrahydropyran group, a piperidine group, a pyrrolidine group, a dioxane group or a dioxolane group.

[0089] In some embodiments of the present invention, the linking group is a PEG linker.

[0090] In some embodiments of the present invention, the PEG linker comprises 2-20 PEG units.

[0091] In some embodiments of the present invention, the reactive group is an azide.

[0092] In some embodiments of the present invention, the linking group conjugated to the reactive group has the structure:

[0093] where m is an integer from 2 to 20, and represents the point of attachment to the structure of Formula Ib.

[0094] In another aspect, the present invention provides an αvβ6 integrin ligand precursor, a tautomer thereof, or a pharmaceutically acceptable salt thereof, comprising a polyethylene glycol (PEG)-azide reactive group selected from:

[0095] In another aspect, the present invention provides an αvβ6 integrin ligand precursor, a tautomer thereof, or a pharmaceutically acceptable salt thereof, comprising an azide-reactive group selected from:

[0096] In another aspect, the present invention provides an αvβ6 integrin ligand precursor selected from:

[0097] or a pharmaceutically acceptable salt thereof.

[0098] In another aspect, the present invention provides an αvβ6 integrin ligand precursor selected from:

[0099] In another aspect, the present invention provides a composition comprising the aforementioned compound or structure, and a pharmaceutically acceptable excipient.

[0100] In some embodiments of the present invention, the above compounds are conjugated to oligonucleotide-based compounds capable of inhibiting target gene expression in epithelial cells.

[0101] In some embodiments of the present invention, the above-mentioned compound is conjugated to an RNAi agent capable of inhibiting the expression of a target gene in epithelial cells.

[0102] In some embodiments of the present invention, the above-mentioned compound is conjugated to an RNAi agent capable of inhibiting the expression of a target gene in bronchiolar epithelial cells.

[0103] In another aspect, the present invention provides a method of delivering one or more transported molecules to a cell, the method comprising administering to the cell the above-described compound or the above-described structure.

[0104] In another aspect, the present invention provides a method for delivering one or more transported molecules to a cell or tissue of a subject in vivo, the method comprising administering to the subject the aforementioned compound, the aforementioned structure, or the aforementioned composition.

[0105] In some embodiments of the present invention, the above-mentioned cells are selected from type I and type II alveolar epithelial cells, goblet cells, secretory epithelial cells, ciliated epithelial cells, corneal and conjunctival epithelial cells, dermal epithelial cells, bile duct epithelial cells, intestinal epithelial cells, ductal epithelial cells, glandular epithelial cells and epithelial tumor cancer.

[0106] In some embodiments of the present invention, the one or more transported molecules comprise oligonucleotide-based compounds.

[0107] In some aspects of the present invention, the oligonucleotide-based compound is an RNAi agent.

[0108] In another aspect, the present invention provides a method for inhibiting target gene expression in a cell in vivo, comprising administering to a subject an effective amount of a composition comprising an oligonucleotide-based compound conjugated to the above-described compound.

[0109] In some embodiments of the present invention, the above-mentioned cells are selected from type I and type II alveolar epithelial cells, goblet cells, secretory epithelial cells, ciliated epithelial cells, corneal and conjunctival epithelial cells, dermal epithelial cells, bile duct epithelial cells, intestinal epithelial cells, ductal epithelial cells, glandular epithelial cells and epithelial tumors.

[0110] In some aspects of the present invention, the oligonucleotide-based compound is an RNAi agent.

[0111] In some embodiments, the αβ integrin ligands disclosed herein can be conjugated to one or more (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30; or 1 to 30, 1 to 25, 1 to 20, 1 to 15, 1 to 10, 1 to 5, 5 to 30, 5 to 25, 5 to 20, 5 to 15, 5 to 10, 10 to 30, 10 to 25, 10 to 20, 10 to 15, 15 to 30, 15 to 25, 15 to 20, 20 to 30, 20 to 25, or 25 to 30) transported molecules (e.g., any transported molecule described herein or known in the art).

[0112] In some embodiments, the αvβ6 integrin ligands disclosed herein are conjugated to one or more transported molecules, optionally via a linker group, such as, for example, a polyethylene glycol (PEG) group.

[0113] In another aspect, the present disclosure provides methods comprising using one or more αvβ6 integrin ligands and / or compositions as described herein, and, if desired, formulating the disclosed αvβ6 integrin ligands and / or compositions into a form suitable for administration as a pharmaceutical product. In other embodiments, the present disclosure provides methods for preparing the ligands and compositions described herein, e.g., medicaments.

[0114] Any of the αvβ6 integrin ligands disclosed herein can be linked to a transported molecule, a reactive group, and / or a protected reactive group. Reactive groups can be used to facilitate conjugation of the αvβ6 integrin ligand to the transported molecule. The αvβ6 integrin ligands disclosed herein can increase targeting of the transported molecule to the αvβ6 integrin or to cells expressing the αvβ6 integrin. The transported molecule can be, but is not limited to, a pharmaceutically active ingredient or compound, a prodrug, or other substance with known therapeutic or diagnostic benefit. In some embodiments, the transported molecule can be, but is not limited to, a small molecule, an antibody, an antibody fragment, an immunoglobulin, a monoclonal antibody, a label or marker, a lipid, a natural or modified oligonucleotide-based compound (e.g., an antisense oligonucleotide or RNAi agent), a natural or modified nucleic acid, a peptide, an aptamer, a polymer, a polyamine, a protein, a toxin, a vitamin, polyethylene glycol, a hapten, digoxin, biotin, a radioactive atom or molecule, or a fluorophore. In some embodiments, the transported molecule comprises a pharmaceutically active ingredient or a prodrug. In some embodiments, the transported molecule comprises an oligonucleotide-based compound as a pharmaceutically active ingredient. In some embodiments, the transported molecule comprises an RNAi agent as a pharmaceutically active ingredient.

[0115] Reactive groups are well known in the art and provide the formation of a covalent bond between two molecules or reactants. Suitable reactive groups for the scope of the present invention include, but are not limited to, amino, amide, carboxylic acid, azide, alkynes, propargyl, BCN (bicyclo [6.1.0] nonyne, DBCO (dibenzocyclooctyne), thiol, maleimido, aminooxy, N-hydroxysuccinimide (NHS) or other activated esters (e.g., PNP, TFP, PFP), bromo, aldehyde, carbonate, tosylate, tetrazine, trans-cyclooctene (TCO), hydrazide, hydroxyl, disulfide, and adjacent pyridyl disulfide groups.

[0116] The incorporation of reactive groups can facilitate conjugation of the αvβ6 integrin ligands disclosed herein to the molecule being transported. Conjugation reactions are well known in the art and provide for the formation of a covalent bond between two molecules or reactants. Suitable conjugation reactions for use within the scope of the present invention include, but are not limited to, amide coupling reactions, Michael addition reactions, hydrazone formation reactions, and click chemistry cycloaddition reactions.

[0117] Protected reactive groups are also commonly used in this area. Protecting groups provide temporary chemical conversion of reactive groups to non-reactive groups under the conditions of non-protecting group reactions, for example, providing chemoselectivity in subsequent chemical reactions. Suitable protected reactive groups for the scope of the present invention include, but are not limited to, Boc groups (tert-butyloxycarbonyl), Fmoc (9-fluorenylmethoxycarbonyl), Cbz groups (carboxybenzyl), benzyl esters and Pbf (2,2,4,6,7-pentamethyldihydrobenzofuran-5-sulfonyl).

[0118] The present invention has the following advantages and beneficial effects compared to the prior art:

[0119] 1. Provided is a synthetic αvβ6 integrin ligand of Formula I, which has serum stability and affinity for integrin αvβ6, specifically exhibiting strong targeting effect. Integrin αvβ6 is a receptor expressed in multiple cell types. The ligand can be used to deliver transported molecules, such as RNAi agents or other oligonucleotide-based compounds, to cells expressing integrin αvβ6, thereby promoting the uptake of the transported molecules into these cells, and exhibits excellent pharmacodynamic activity after binding to the RNAi agent.

[0120] 2. Provided are a composition comprising an αvβ6 integrin ligand and a method of use.

[0121] 3. Provided is a synthetic αvβ6 integrin ligand compound of formula I, which has a good αvβ6 integrin inhibitory effect and thus has an inhibitory effect on tumor growth.

[0122] 4. Provided is a method for synthesizing the compound of the present invention, which can be used for production and preparation.

[0123] Definition and Description

[0124] Unless otherwise indicated, the following terms and phrases used herein are intended to have the following meanings. A particular term or phrase should not be construed as indefinite or unclear unless specifically defined, but rather should be understood in accordance with its ordinary meaning. When a trade name appears in this document, it is intended to refer to the corresponding commercial product or its active ingredient.

[0125] The term "pharmaceutically acceptable" as used herein refers to those compounds, materials, compositions and / or dosage forms which, within the scope of sound medical judgment, are suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response or other problems or complications, commensurate with a reasonable benefit / risk ratio.

[0126] The term "pharmaceutically acceptable salt" refers to salts of the compounds of the present invention, prepared by reacting the compounds of the present invention with relatively nontoxic acids or bases. When the compounds of the present invention contain relatively acidic functional groups, base addition salts can be obtained by contacting the neutral form of such compounds with a sufficient amount of base in neat solution or in a suitable inert solvent. Pharmaceutically acceptable base addition salts include sodium, potassium, calcium, ammonium, organic amine, or magnesium salts, or similar salts. When the compounds of the present invention contain relatively basic functional groups, acid addition salts can be obtained by contacting the neutral form of such compounds with a sufficient amount of acid in neat solution or in a suitable inert solvent. Examples of pharmaceutically acceptable acid addition salts include inorganic acid salts such as hydrochloric acid, hydrobromic acid, nitric acid, carbonic acid, bicarbonate, phosphoric acid, monohydrogen phosphate, dihydrogen phosphate, sulfuric acid, bisulfate, hydroiodic acid, phosphorous acid, and the like; and organic acid salts such as acetic acid, propionic acid, isobutyric acid, maleic acid, malonic acid, benzoic acid, succinic acid, suberic acid, fumaric acid, lactic acid, mandelic acid, phthalic acid, benzenesulfonic acid, p-toluenesulfonic acid, citric acid, tartaric acid, and methanesulfonic acid, as well as salts of amino acids (such as arginine) and organic acids such as glucuronic acid. Certain specific compounds of the present invention contain both basic and acidic functional groups and can be converted into either base or acid addition salts.

[0127] Pharmaceutically acceptable salts of the present invention can be synthesized by conventional chemical methods from parent compounds containing acid radicals or bases. Generally, such salts are prepared by reacting these compounds in free acid or base form with a stoichiometric amount of a suitable base or acid in water or an organic solvent or a mixture of the two.

[0128] "Pharmaceutical composition" means a composition containing one or more compounds described herein, their isomers or pharmaceutically acceptable salts thereof, and other components such as physiological / pharmaceutically acceptable carriers and excipients. The purpose of a pharmaceutical composition is to promote administration to an organism, facilitate the absorption of the active ingredient, and thus exert biological activity. The pharmaceutical compositions described herein may contain other additional components commonly found in pharmaceutical compositions. In some embodiments, the additional components are pharmaceutically active materials. Pharmaceutically active materials include, but are not limited to, antipruritics, astringents, local anesthetics or anti-inflammatory agents (e.g., antihistamines, diphenhydramine, etc.), small molecule drugs, antibodies, antibody fragments, nucleic acid aptamers and / or vaccines. Pharmaceutical compositions may also contain preservatives, solubilizers, stabilizers, wetting agents, emulsifiers, sweeteners, colorants, odorants, salts for changing osmotic pressure, buffers, coating agents, or antioxidants. They may also contain other agents with known therapeutic benefits.

[0129] Excipients include, but are not limited to, absorption enhancers, antiadherents, antifoaming agents, antioxidants, binders, buffers, carriers, coatings, colorants, delivery enhancers, delivery polymers, dextran, dextrose, diluents, disintegrants, emulsifiers, extenders, fillers, flavorings, glidants, wetting agents, lubricants, oils, polymers, preservatives, saline, salts, solvents, sugars, suspending agents, sustained release matrices, sweeteners, thickeners, tonicity agents, vehicles, hydrophobic agents, and wetting agents.

[0130] Unless otherwise indicated, the term "isomer" is intended to include geometric isomers, cis-trans isomers, stereoisomers, enantiomers, optical isomers, diastereomers and tautomers.

[0131] The compounds of the present invention may exist in specific geometric or stereoisomeric forms. The present invention contemplates all such compounds, including cis- and trans-isomers, (-)- and (+)-enantiomers, (R)- and (S)-enantiomers, diastereomers, (D)-isomers, (L)-isomers, and racemic mixtures and other mixtures thereof, such as enantiomerically or diastereomerically enriched mixtures, all of which are within the scope of the present invention. Additional asymmetric carbon atoms may be present in substituents such as alkyl groups. All such isomers and mixtures thereof are encompassed within the scope of the present invention.

[0132] Unless otherwise indicated, the term "enantiomer" or "optical isomer" refers to stereoisomers that are mirror images of one another.

[0133] Unless otherwise indicated, the term "cis-trans isomers" or "geometric isomers" arises from the inability to rotate freely about double bonds or single bonds forming ring carbon atoms.

[0134] Unless otherwise indicated, the term "diastereomer" refers to stereoisomers that have two or more chiral centers and that are not mirror images of each other.

[0135] Unless otherwise indicated, "(+)" indicates dextrorotatory, "(-)" indicates levorotatory, and "(±)" indicates racemic.

[0136] Unless otherwise specified, use a solid wedge key. and dotted wedge key To indicate the absolute configuration of a stereocenter, use a straight solid bond and straight dashed key Indicate the relative configuration of stereocenters with a wavy line Indicates a wedge-shaped solid key or dotted wedge key Or use a wavy line Indicates a straight solid bond or straight dashed key

[0137] Unless otherwise indicated, the terms "enriched in one isomer", "isomerically enriched", "enriched in one enantiomer" or "enantiomerically enriched" mean that the content of one isomer or enantiomer is less than 100%, and the content of that isomer or enantiomer is greater than or equal to 60%, or greater than or equal to 70%, or greater than or equal to 80%, or greater than or equal to 90%, or greater than or equal to 95%, or greater than or equal to 96%, or greater than or equal to 97%, or greater than or equal to 98%, or greater than or equal to 99%, or greater than or equal to 99.5%, or greater than or equal to 99.6%, or greater than or equal to 99.7%, or greater than or equal to 99.8%, or greater than or equal to 99.9%.

[0138] Unless otherwise indicated, the term "isomer excess" or "enantiomeric excess" refers to the difference between the relative percentages of two isomers or two enantiomers. For example, if the content of one isomer or enantiomer is 90% and the content of the other isomer or enantiomer is 10%, the isomer or enantiomeric excess (ee value) is 80%.

[0139] Optically active (R)- and (S)-isomers, as well as D and L isomers, can be prepared by chiral synthesis or chiral reagents or other conventional techniques. If one enantiomer of a compound of the present invention is desired, it can be prepared by asymmetric synthesis or derivatization with a chiral auxiliary, wherein the resulting diastereomeric mixture is separated and the auxiliary group is cleaved to provide the pure desired enantiomer. Alternatively, when the molecule contains a basic functional group (such as an amino group) or an acidic functional group (such as a carboxyl group), diastereomeric salts are formed with an appropriate optically active acid or base, followed by diastereomeric resolution by conventional methods known in the art, and then the pure enantiomers are recovered. In addition, the separation of enantiomers and diastereomers is typically accomplished using chromatography, which employs a chiral stationary phase and is optionally combined with a chemical derivatization method (e.g., formation of carbamates from amines).

[0140] The compounds of the present invention may contain unnatural proportions of atomic isotopes on one or more atoms constituting the compound. For example, the compound may be labeled with a radioactive isotope, such as tritium (3H), iodine-125 (125I), or C-14 (14C). As another example, deuterated drugs may be formed by replacing hydrogen with heavy hydrogen. The bond formed by deuterium and carbon is stronger than the bond formed by ordinary hydrogen and carbon. Compared to non-deuterated drugs, deuterated drugs have advantages such as reduced toxic side effects, increased drug stability, enhanced therapeutic efficacy, and extended drug biological half-life. All isotopic composition changes of the compounds of the present invention, whether radioactive or not, are included within the scope of the present invention.

[0141] The terms "optional" or "optionally" mean that the subsequently described event or circumstance may but need not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0142] The term "substituted" means that any one or more hydrogen atoms on a particular atom are replaced by a substituent, which may include deuterium and hydrogen variants, as long as the valence state of the particular atom is normal and the substituted compound is stable. When the substituent is oxygen (i.e., =O), it means that two hydrogen atoms are replaced. Oxygen substitution does not occur on aromatic groups. The term "optionally substituted" means that it may be substituted or unsubstituted, and unless otherwise specified, the type and number of substituents can be any on the basis of chemical achievable.

[0143] When any variable (e.g., R) occurs more than once in a compound's composition or structure, its definition at each occurrence is independent. Thus, for example, if a group is substituted with 0-2 Rs, the group may be optionally substituted with up to two Rs, with each occurrence of R being an independent choice. Furthermore, combinations of substituents and / or their variants are permissible only if such combinations result in stable compounds.

[0144] When the number of a linking group is 0, such as -(CRR)0-, it means that the linking group is a single bond.

[0145] When the number of a substituent is 0, it means that the substituent does not exist, for example, -A-(R)0 means that the structure is actually -A.

[0146] When a substituent is vacant, it means that the substituent does not exist. For example, when X in AX is vacant, it means that the structure is actually A.

[0147] When one of the variables is selected from a single bond, it means that the two groups it connects are directly connected. For example, when L in ALZ represents a single bond, it means that the structure is actually AZ.

[0148] When a substituent's bond can cross-link to two or more atoms in a ring, the substituent can be bonded to any atom in the ring, e.g. The substituent R can be substituted at any position on the cyclohexyl group or cyclohexadiene. When the listed substituent does not specify the atom through which it is bonded to the substituted group, the substituent can be bonded through any atom. For example, a pyridyl substituent can be bonded to the substituted group through any carbon atom on the pyridine ring.

[0149] When the linking group is listed without specifying its linking direction, its linking direction is arbitrary, for example, The connecting group L is -MW-, in which case -MW- can connect ring A and ring A in the same direction as the reading order from left to right to form You can also connect ring A and ring A in the opposite direction of reading from left to right to form Combinations of linkers, substituents, and / or variations thereof are permissible only if such combinations result in stable compounds.

[0150] A linker or linking group is a connection between two atoms that connects one chemical group (such as an RNAi agent) or a fragment of interest to another chemical group (such as an αvβ6 ligand, a pharmacokinetic modulator, or a delivery polymer) or a fragment of interest via one or more covalent bonds. An unstable connection contains an unstable bond. The connection may optionally include a spacer group that increases the distance between the two connected atoms. The spacer group can further increase the flexibility and / or length of the connection. Spacer groups include, but are not limited to, alkyl groups, alkenyl groups, alkynyl groups, aryl groups, aralkyl groups, aralkenyl groups, and aralkynyl groups; each of which may contain one or more heteroatoms, heterocycles, amino acids, nucleotides, and sugars. Spacer groups are well known in the art, and the foregoing list is not meant to limit the scope of this specification.

[0151] In some embodiments, the αβ ligand is linked to the transported molecule without the use of an additional linker. In some embodiments, the αβ ligand is designed with a readily available linker to facilitate attachment to the transported molecule. In some embodiments, when two or more RNAi agents are included in the composition, the two or more RNAi agents can be linked to their respective targeting groups using the same linker. In some embodiments, when two or more RNAi agents are included in the composition, different linkers are used to link the two or more RNAi agents to their respective targeting groups.

[0152] Unless otherwise specified, when a group has one or more connectable sites, any one or more sites of the group can be connected to other groups through chemical bonds. When the chemical bond connection mode is non-positional and there are H atoms at the connectable sites, when the chemical bond is connected, the number of H atoms at the site will decrease accordingly with the number of connected chemical bonds, and become a group with a corresponding valence. The chemical bond connecting the site to other groups can be a straight solid bond. Straight dotted key or wavy lines For example, the straight solid bond in -OCH3 indicates that it is connected to other groups through the oxygen atom in the group; The straight dashed bond in the group indicates that the two ends of the nitrogen atom in the group are connected to other groups; The wavy lines in the phenyl group represent the connection to other groups through the carbon atoms at positions 1 and 2 in the phenyl group.

[0153] Unless otherwise specified, "halo" or "halogen" refers to fluorine, chlorine, bromine, and iodine; "halo" refers to monohalo or polyhalo, such as "haloalkane" refers to monohaloalkyl or polyhaloalkyl, and the polyhalo may be the same halogen atom or different halogen atoms; specifically, halomethyl includes but is not limited to chloromethyl, dichloromethyl, trifluoromethyl, etc.

[0154] "Alkoxy" represents an alkyl group as described above with a specific number of carbon atoms connected through an oxygen bridge. Unless otherwise specified, C1-6 alkoxy includes C1, C2, C3, C4, C5, and C6 alkoxy. Examples of alkoxy include, but are not limited to, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, n-pentoxy, and S-pentoxy.

[0155] Unless otherwise specified, the term "aryl" refers to a polyunsaturated aromatic hydrocarbon substituent that can be monosubstituted or polysubstituted, can be monovalent, divalent or polyvalent, can be monocyclic or polycyclic (e.g., 1 to 3 rings; at least one of which is aromatic), which are fused together or covalently linked. The term "heteroaryl" refers to an aryl group (or ring) containing one to four heteroatoms. In an exemplary embodiment, the heteroatoms are selected from B, N, O and S, wherein the nitrogen and sulfur atoms are optionally oxidized and the nitrogen atom is optionally quaternized. The heteroaryl group can be attached to the rest of the molecule through the heteroatom. Non-limiting examples of aryl or heteroaryl groups include phenyl, naphthyl, biphenyl, pyrrolyl, pyrazolyl, imidazolyl, pyrazinyl, oxazolyl, phenyl-oxazolyl, isoxazolyl, thiazolyl, furanyl, thienyl, pyridyl, pyrimidinyl, benzothiazolyl, purinyl, benzimidazolyl, indolyl, isoquinolyl, quinoxalinyl, quinolyl, 1-naphthyl, 2-naphthyl, 4-biphenyl, 1-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl, 3-pyrazolyl, 2-imidazolyl, 4-imidazolyl, pyrazinyl, 2-oxazolyl, 4-oxazolyl phenyl, 2-phenyl-4-oxazolyl, 5-oxazolyl, 3-isoxazolyl, 4-isoxazolyl, 5-isoxazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 2-furyl, 3-furyl, 2-thienyl, 3-thienyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-pyrimidinyl, 4-pyrimidinyl, 5-benzothiazolyl, purinyl, 2-benzimidazolyl, 5-indolyl, 1-isoquinolyl, 5-isoquinolyl, 2-quinoxalinyl, 5-quinoxalinyl, 3-quinolyl, and 6-quinolyl.

[0156] The term "leaving group" refers to a functional group or atom that can be replaced by another functional group or atom through a substitution reaction (e.g., an affine substitution reaction). For example, representative leaving groups include trifluoromethanesulfonate; chloro, bromo, iodo; sulfonate groups such as methanesulfonate, toluenesulfonate, p-bromobenzenesulfonate, p-toluenesulfonate, etc.; acyloxy groups such as acetoxy and trifluoroacetoxy, etc.

[0157] The term "protecting group" includes, but is not limited to, an "amino protecting group," a "hydroxy protecting group," or a "thiol protecting group." The term "amino protecting group" refers to a protecting group suitable for preventing side reactions at the amino nitrogen position. Representative amino protecting groups include, but are not limited to, formyl; acyl, such as alkanoyl (e.g., acetyl, trichloroacetyl, or trifluoroacetyl); alkoxycarbonyl, such as tert-butyloxycarbonyl (Boc); arylmethoxycarbonyl, such as benzyloxycarbonyl (Cbz) and 9-fluorenylmethoxycarbonyl (Fmoc); arylmethyl, such as benzyl (Bn), trityl (Tr), 1,1-bis-(4'-methoxyphenyl)methyl; silyl, such as trimethylsilyl (TMS) and tert-butyldimethylsilyl (TBS), and the like. The term "hydroxy protecting group" refers to a protecting group suitable for preventing side reactions at the hydroxyl group. Representative hydroxy protecting groups include, but are not limited to, alkyl groups such as methyl, ethyl and tert-butyl; acyl groups such as alkanoyl (e.g., acetyl); arylmethyl groups such as benzyl (Bn), p-methoxybenzyl (PMB), 3,4-dimethoxybenzyl (3,4-DMPM); silyl groups such as trimethylsilyl (TMS) and tert-butyldimethylsilyl (TBS), and the like.

[0158] Unless otherwise specified, C n-n+m Alkyl or C n -C n+m Alkyl groups include saturated hydrocarbon groups with n to n+m carbon atoms, for example, C 1-12 Alkyl groups include C1, C2, C3, C4, C5, C6, C7, C8, C9, C 10 、C 11 , and C 12 The alkyl group also includes any range from n to n+m, such as C 1-12 Alkyl groups include C 1-3 、C 1-6 、C 1-9 、C 3-6 、C 3-9 、C 3-12 、C 6-9 、C 6-12 , and C 9-12 It can be monovalent (such as methyl), divalent (such as methylene) or polyvalent (such as methine), for example C 1-4 Examples of alkyl groups include, but are not limited to, methyl (Me), ethyl (Et), propyl (including n-propyl and isopropyl), butyl (including n-butyl, isobutyl, s-butyl and t-butyl), and the like.

[0159] Unless otherwise specified, "alkenyl" refers to an alkyl group having one or more carbon-carbon double bonds at any position of the chain, which may be monosubstituted or polysubstituted and may be monovalent, divalent, or polyvalent. Examples of alkenyl groups include ethenyl, propenyl, butenyl, pentenyl, hexenyl, butadienyl, piperyl, hexadienyl, and the like.

[0160] Unless otherwise specified, "alkynyl" refers to an alkyl group having one or more carbon-carbon triple bonds at any position of the chain, which may be monosubstituted or polysubstituted and may be monovalent, divalent, or polyvalent. Examples of alkynyl groups include ethynyl, propynyl, butynyl, pentynyl, and the like.

[0161] Unless otherwise specified, the number of atoms in a ring is generally defined as the number of ring members, for example, a "5-7 membered ring" refers to a "ring" of 5-7 atoms; a "C 3-n "Cycloalkyl" means a saturated cyclic hydrocarbon group consisting of 3 to n carbon atoms, including monocyclic, bicyclic and tricyclic ring systems, wherein the bicyclic and tricyclic ring systems include spirocyclic, fused and bridged rings, for example, "C 3-10 "Cycloalkyl" refers to a saturated cyclic hydrocarbon group consisting of 3 to 10 carbon atoms, including monocyclic, bicyclic and tricyclic ring systems, wherein the bicyclic and tricyclic ring systems include spirocyclic, fused and bridged rings. 3-10 Cycloalkyl groups include C 3-8 、C 3-6 、C 3-5 、C 4-10 、C 4-8 、C 4-6 、C 4-5 、C 5-8 or C 5-6 It can be monovalent, divalent or polyvalent. 3-10 Examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, norbornyl, [2.2.2]bicyclooctane, [4.4.0]bicyclodecane, and the like.

[0162] Unless otherwise specified, cycloalkenyl includes any stable cyclic or polycyclic hydrocarbon radical containing one or more unsaturated carbon-carbon double bonds at any position of the ring, which may be monosubstituted or polysubstituted and may be monovalent, divalent or polyvalent. Examples of such cycloalkenyl radicals include, but are not limited to, cyclopentenyl, cyclohexenyl, and the like.

[0163] Unless otherwise specified, cycloalkynyl groups include any stable cyclic or polycyclic hydrocarbon group containing one or more carbon-carbon triple bonds at any position of the ring, which may be monosubstituted or polysubstituted, and may be monovalent, divalent, or polyvalent.

[0164] Unless otherwise specified, the term "3-n-membered heterocycloalkyl" by itself or in combination with other terms refers to a saturated cyclic group consisting of 3 to n ring atoms, wherein the heteroatoms of the heterocycloalkyl group are independently selected from O, S, N, P and Se, and the rest are carbon atoms, wherein the nitrogen atom is optionally quaternized, and the nitrogen, sulfur and phosphorus heteroatoms are optionally oxidized (i.e., NO, S(O) p and P(O) p , p is 1 or 2). It includes monocyclic, bicyclic and tricyclic ring systems, wherein bicyclic and tricyclic ring systems include spirocyclic, fused and bridged rings. For example, "3-10 membered heterocycloalkyl" by itself or in combination with other terms refers to a saturated cyclic group consisting of 3 to 10 ring atoms, wherein the heteroatoms are independently selected from O, S, N, P and Se, and the rest are carbon atoms, wherein the nitrogen atoms are optionally quaternized, and the nitrogen, sulfur and phosphorus heteroatoms are optionally oxidized (i.e., NO, S(O) p and P(O) p , p is 1 or 2). It includes monocyclic, bicyclic and tricyclic ring systems, wherein the bicyclic and tricyclic ring systems include spirocyclic, fused and bridged rings, and the "3-10 membered heterocycloalkyl" also includes 3-9 membered, 3-8 membered, 3-6 membered, 5-9 membered, 5 membered, 6 membered, 7 membered, 8 membered and 9 membered heterocycloalkyl, etc. Specifically, the "3-10 membered heterocycloalkyl" may include but is not limited to azetidinyl, oxetanyl, thietanyl, pyrrolidinyl, pyrazolidinyl, imidazolidinyl, tetrahydrothiophene (including tetrahydrothiophen-2-yl and tetrahydrothiophen-3-yl, etc.), tetrahydrofuranyl (including tetrahydrofuran-2-yl, etc.), tetrahydropyranyl, piperidinyl (including 1-piperidinyl, 2-piperidinyl and 3-piperidinyl, etc.), piperazinyl (including 1-piperazinyl and 2-piperazinyl, etc.), morpholinyl (including 3-morpholinyl and 4-morpholinyl, etc.), dioxanyl, dithianyl, isoxazolidinyl, isothiazolidinyl, 1,2-oxazinyl, 1,2-thiazinyl, hexahydropyridazinyl, homopiperazinyl, homopiperidinyl or dioxepanyl, etc.

[0165] "Oligonucleotide-based compounds" include, but are not limited to, single-stranded oligonucleotides, single-stranded antisense oligonucleotides, short interfering RNA (siRNA), double-stranded RNA (dsRNA), microRNA (miRNA), short hairpin RNA (shRNA), ribozymes, interfering RNA molecules, and dicer substrates. In some embodiments, the oligonucleotide-based compound is a single-stranded oligonucleotide, such as an antisense oligonucleotide. In some embodiments, the oligonucleotide-based compound is a double-stranded oligonucleotide. In some embodiments, the oligonucleotide-based compound is a double-stranded oligonucleotide, which is an RNAi agent.

[0166] In some embodiments, one or more transported molecules are "RNAi agents", which are defined herein as compositions containing RNA or RNA-like (e.g., chemically modified RNA) oligonucleotide molecules that can degrade or inhibit the translation of messenger RNA (mRNA) transcripts of target mRNA in a sequence-specific manner. As used herein, RNAi agents can act by RNA interference mechanisms (i.e., by inducing RNA interference by interacting with the RNA interference pathway mechanism (RNA-induced silencing complex or RISC) of mammalian cells) or by any one or more alternative mechanisms or pathways. Although it is believed that RNAi agents, as the term is used herein, act primarily by RNA interference mechanisms, the disclosed RNAi agents are not bound or limited by any particular pathway or mechanism of action. RNAi agents disclosed herein are composed of sense strands and antisense strands, and include but are not limited to: short (or small) interfering RNA (siRNA), double-stranded RNA (dsRNA), microRNA (miRNA), short hairpin RNA (shRNA) and dicer substrates. The antisense strand of the RNAi agent described herein is at least partially complementary to the targeted mRNA. The RNAi agent can include one or more modified nucleotides and / or one or more non-phosphodiester bonds.

[0167] Oligonucleotide-based compounds, particularly RNAi agents, can generally be composed of modified nucleotides and / or one or more non-phosphodiester bonds. As used herein, "modified nucleotides" are nucleotides other than ribonucleotides (2'-hydroxy nucleotides). In some embodiments, at least 50% (e.g., at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 97%, at least 98%, at least 99% or 100%) of the nucleotides are modified nucleotides. As used herein, modified nucleotides include, but are not limited to, deoxyribonucleotides, nucleotide mimetics, abasic nucleotides, 2'-modified nucleotides, 3' to 3' linkage (inverted) nucleotides, nucleotides containing non-natural bases, bridged nucleotides, peptide nucleic acids, 2', 3'-acyclic nucleotide mimetics (unlocked nucleobase analogs), locked nucleotides, 3'-O-methoxy (2' internucleoside linkage) nucleotides, 2'-F-arabinonucleotides, 5'-Me, 2'-fluoro nucleotides, morpholino nucleotides, vinylphosphonate deoxyribonucleotides, vinylphosphonate-containing nucleotides, and cyclopropylphosphonate-containing nucleotides. 2'-modified nucleotides (i.e., nucleotides having a group other than a hydroxyl group at the 2' position of the five-membered sugar ring) include, but are not limited to, 2'-O-methyl nucleotides, 2'-deoxy-2'-fluoro nucleotides, 2'-deoxy nucleotides, 2'-methoxyethyl (2'-O-2-methoxyethyl) nucleotides, 2'-amino nucleotides, and 2'-alkyl nucleotides.

[0168] In addition, one or more nucleotides of an oligonucleotide-based compound (such as an RNAi agent) can be linked by non-standard bonds or backbones (i.e., modified internucleoside bonds or modified backbones). The modified internucleoside linkage can be a non-phosphate-containing covalent internucleoside bond. Modified internucleoside linkages or backbones include, but are not limited to, 5'-phosphorothioate groups, chiral phosphorothioates, phosphorothioates, phosphorodithioates, phosphotriesters, aminoalkyl-phosphotriesters, alkyl phosphonates (e.g., methylphosphonate or 3'-alkylenephosphonate), chiral phosphonates, phosphinates, phosphoramidates (e.g., 3'-aminophosphoramidate, aminoalkylphosphoramidate, or thiophosphoramidate), thioalkyl-phosphonates, thioalkylphosphotriesters, morpholino linkages, boranophosphates with normal 3'-5' linkages, 2'-5' linked analogs of boranophosphates, or boranophosphates with reverse polarity where adjacent pairs of nucleoside units are linked 3'-5' to 5'-3' or 2'-5' to 5'-2'.

[0169] It is not necessary that all positions in a given compound be uniformly modified. Rather, more than one modification may be incorporated into a single oligonucleotide-based compound or even a single nucleotide thereof.

[0170] The αvβ6 integrin ligand includes salts or solvates thereof. A solvate of an αvβ6 integrin ligand refers to the addition of inert solvent molecules to the αvβ6 integrin ligand, which is formed due to their mutual attraction. Solvates are, for example, mono- or dihydrates or addition compounds with alcohols, such as, for example, methanol or ethanol.

[0171] Free amino groups or free hydroxyl groups can be provided as substituents of the αvβ6 integrin ligand together with corresponding protecting groups. The αvβ6 integrin ligand also includes, for example, derivatives, i.e., αvβ6 integrin ligands modified with, for example, alkyl or acyl groups, sugars or oligopeptides, which are cleaved in vitro or in vivo.

[0172] In some embodiments, the αvβ6 integrin ligands disclosed herein facilitate delivery of transported molecules to the cytoplasm of cells that present the αvβ6 integrin on their surface by ligand-mediated endocytosis, pinocytosis, or by other means. In some embodiments, the αvβ6 integrin ligands disclosed herein facilitate delivery of transported molecules to the plasma membrane of cells that present the αvβ6 integrin.

[0173] The compounds of the present invention can be prepared by a variety of synthetic methods well known to those skilled in the art, including the specific embodiments listed below, embodiments formed by combining them with other chemical synthesis methods, and equivalent substitutions well known to those skilled in the art. Preferred embodiments include but are not limited to the examples of the present invention.

[0174] The structures of the compounds of the present invention can be confirmed by conventional methods well known to those skilled in the art. If the present invention relates to the absolute configuration of the compounds, the absolute configuration can be confirmed by conventional techniques in the art. For example, single crystal X-ray diffraction (SXRD) is used to collect diffraction intensity data on the cultured single crystal using a Bruker D8 venture diffractometer, using CuKα radiation as the light source and scanning mode: After scanning and collecting relevant data, the crystal structure is further analyzed using the direct method (Shelxs97) to confirm the absolute configuration.

[0175] The solvent used in the present invention is commercially available.

[0176] The present invention uses the following abbreviations:

[0177] Compounds are named according to the conventional nomenclature in the art or using Software naming, commercially available compounds use supplier catalog names. DETAILED DESCRIPTION

[0178] The present invention will be described in further detail below with reference to the embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0179] Example 1: 3-Cyclopropyl-3-(3-((1-(2-((4-(dodecyloxy)phenyl)(neopentyl)carbamoyl)-5-methoxyphenyl)piperidin-4-yl)methoxy)phenyl)propanoic acid (1)

[0180] Synthesis route:

[0181] Step 1: (S)-methyl 3-(4-bromophenyl)-3-((tert-butoxycarbonyl)amino)propanoate (1-6-2)

[0182] To a clean 250 mL single-necked flask, add (S)-3-(4-bromophenyl)-3-((tert-butoxycarbonyl)amino)propanoic acid (5 g, 14.53 mmol), DMF (25 mL), and potassium carbonate (3.01 g, 21.80 mmol). Stir for 15 minutes, then add iodomethane (3.71 g, 26.15 mmol) dropwise. Continue the reaction at room temperature. Workup: Add water (100 mL), extract with ethyl acetate (30 mL x 2), wash the organic phase with saturated brine (30 mL x 4), dry over anhydrous sodium sulfate, filter, and purify by column chromatography (PE / EA (v / v) = 4 / 1) to obtain the title compound as a white solid (5.14 g, 98.85%).

[0183] MS:(ESI,pos.ion)m / z:380.0454[M+Na] +

[0184] Step 2: (S)-3-amino-3-(4-bromophenyl)propionic acid methyl ester hydrochloride (1-6-3)

[0185] To a clean 100 mL single-necked flask, add methyl (S)-3-(4-bromophenyl)-3-((tert-butoxycarbonyl)amino)propanoate (5.14 g, 14.35 mmol) and a 4N solution of hydrogen chloride in dioxane (35.88 mL, 143.5 mmol). Stir the mixture at room temperature. Workup: Concentrate under reduced pressure to constant weight to obtain a white solid (4.23 g, 100%).

[0186] MS:(ESI,pos.ion)m / z:258.015[M+H] +

[0187] Step 3: (S)-methyl 3-(4-bromophenyl)-3-(2-((tert-butoxycarbonyl)amino)acetamido)propanoate (1-6-4)

[0188] To a clean 250 mL single-necked flask, add (tert-butyloxycarbonyl)glycine (3.77 g, 21.52 mmol), DMF (64 mL), and HATU (10.575 g, 28.7 mmol). Stir at room temperature for 0.5 h, then add (S)-methyl 3-amino-3-(4-bromophenyl)propanoate hydrochloride (4.23 g, 14.53 mmol) at 0°C. DIPEA (9.31 g, 71.75 mmol) was added dropwise. After completion of the addition, the mixture was allowed to react at room temperature. Workup: Add water (200 mL), extract with ethyl acetate (60 mL x 2), combine the organic phases, wash with saturated brine (60 mL x 4), dry over anhydrous sodium sulfate, filter, concentrate, and purify by column chromatography (DCM / MeOH (v / v) = 20 / 1) to obtain the title compound as a red oil (6.5 g, 100%).

[0189] MS:(ESI,pos.ion)m / z:359.0273[M-56+H] +

[0190] Step 4: (S)-methyl 3-(4-(4-(benzyloxy)naphthalen-1-yl)phenyl)-3-(2-(((tert-butoxycarbonyl)amino)acetamido)propanoate (1-6-5)

[0191] In a 100 mL two-necked flask, (S)-methyl 3-(4-bromophenyl)-3-(2-((tert-butoxycarbonyl)amino)acetamido)propanoate (1.25 g, 3.01 mmol), 2-(4-(benzyloxy)naphthalen-1-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1.63 g, 4.51 mmol), tetrahydrofuran (33 mL), water (8.34 mL), potassium phosphate (1.28 g, 6.02 mmol) and XPhos Pd G2 (118.26 mg, 0.15 mmol) were added. The atmosphere was replaced with nitrogen and the mixture was stirred at room temperature for 8 hours. Post-treatment: ethyl acetate (40 mL) and saturated brine (40 mL) were added for separation, the aqueous phase was extracted with ethyl acetate (30 mL × 3), the organic phases were combined, washed with saturated brine (30 mL × 2), dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure and purified by column chromatography (PE / EA (V / V) = 10 / 1) to give the title compound as a colorless oil (1.25 g, 73.03%).

[0192] MS:(ESI,pos.ion)m / z:513.2037[M-56+H] +

[0193] Step 5: (S)-methyl 3-(2-aminoacetamido)-3-(4-(4-(benzyloxy)naphthalen-1-yl)phenyl)propanoate hydrochloride (1-6)

[0194] To a 50 mL single-necked flask was added methyl (S)-3-(4-(4-(benzyloxy)naphthalen-1-yl)phenyl)-3-(2-(((tert-butoxycarbonyl)amino)acetamido)propanoate (0.4 g, 0.703 mmol). After cooling to 0°C, a 4N solution of hydrogen chloride in dioxane (1.75 g, 14.07 mmol) was added. After addition, the mixture was stirred at room temperature for 8 hours. Post-treatment: The reaction mixture was directly dried and used in the next step to obtain the title compound as a colorless oil (270 mg, 81.90%).

[0195] MS:(ESI,pos.ion)m / z:469.20[M+H] +

[0196] Step 6: Ethyl 4-(1,8-naphthyridin-2-yl)butanoate (1-2)

[0197] To a clean 500 mL single-necked flask, add 2-aminonicotinaldehyde (10 g, 81.88 mmol), ethyl 5-oxohexanoate (25.91 g, 163.76 mmol), L-proline (2.36 g, 20.47 mmol), and ethanol (100 mL). Stir and react at 80°C. Post-treatment: Cool to room temperature and purify by column chromatography (PE / EA (V / V) = 2 / 1) to obtain the title compound as a yellow oil (11.90 g, 59.50%).

[0198] MS:(ESI,pos.ion)m / z:245.1388[M+H] +

[0199] Step 7: Ethyl 4-(5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)butanoate (1-3)

[0200] To a clean 500 mL single-necked flask, add ethyl 4-(1,8-naphthyridin-2-yl)butanoate (11.90 g, 48.71 mmol), ethyl acetate (239 mL), and 10% Pd / C (1.19 g). Vacuum the mixture and replace the atmosphere with hydrogen three times. The reaction was allowed to proceed at room temperature under a hydrogen atmosphere. Workup: filtration and purification by column chromatography (DCM / MeOH (v / v) = 20 / 1) afforded the title compound as a yellow oil (11.66 g, 96.36%).

[0201] MS:(ESI,pos.ion)m / z:249.1786[M+H] +

[0202] Step 8: tert-Butyl 7-(4-ethoxy-4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (1-4)

[0203] To a clean 500 mL three-necked flask, add ethyl 4-(5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)butanoate (10 g, 40.27 mmol), Boc anhydride (26.37 g, 120.81 mmol), and tetrahydrofuran (100 mL). Add 1N LiHMDS solution in tetrahydrofuran (60.405 mL, 60.405 mmol) dropwise at 0°C under nitrogen. After completion, bring the mixture to room temperature for reaction. Workup: Add 200 mL of water and extract with ethyl acetate (100 mL x 2). The combined organic phases are dried over anhydrous sodium sulfate, filtered, and the filtrate is concentrated under reduced pressure. Purification by column chromatography (PE / EA (V / V) = 4 / 1) affords the title compound as a colorless oil (11.88 g, 84.68%).

[0204] MS:(ESI,pos.ion)m / z:349.2241[M+H] +

[0205] Step 9: 4-(8-(tert-Butoxycarbonyl)-5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)butanoic acid (1-5)

[0206] To a clean 250 mL single-necked flask, add tert-butyl 7-(4-ethoxy-4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (6.0 g, 17.24 mmol), THF (24 mL), MeOH (24 mL), and water (24 mL). LiOH (0.7 g, 29.31 mmol) was added at 0°C and the mixture was allowed to react at room temperature. Post-treatment: Adjust the pH to 5-6 with 6% citric acid. Extract with dichloromethane (60 mL x 2). Combine the organic phases, dry over anhydrous sodium sulfate, filter, and concentrate the filtrate under reduced pressure. Purify by column chromatography (DCM / MeOH (v / v) = 20 / 1) to obtain the title compound as a pale yellow oil (2.90 g, 52.54%).

[0207] MS:(ESI,pos.ion)m / z:321.1908[M+H] +

[0208] Step 10: (S)-tert-Butyl 7-(4-((2-((1-(4-(4-(benzyloxy)naphth-1-yl)phenyl)-3-methoxy-3-oxopropyl)amino)-2-oxoethyl)amino)-4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (1-7)

[0209] In a clean 100 mL single-necked flask, 4-(8-(tert-butoxycarbonyl)-5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)butanoic acid (0.928 g, 2.81 mmol), DMF (20 mL), and HATU (2.0 g, 5.27 mmol) were added. After stirring at room temperature for 0.5 h, (S)-methyl 3-(2-aminoacetamido)-3-(4-(4-(benzyloxy)naphthalen-1-yl)phenyl)propanoate hydrochloride (1.33 g, 2.63 mmol) was added at 0°C, and DIPEA (1.70 g, 13.17 mmol) was added dropwise. After completion of the addition, the mixture was brought to room temperature for reaction. Post-treatment: water (100 mL) was added, extracted with ethyl acetate (30 mL × 2), the organic phases were combined, washed with saturated brine (30 mL × 4), dried over anhydrous sodium sulfate, filtered, concentrated, and purified by column chromatography (DCM / MeOH (V / V) = 40 / 1) to give the title compound as a yellow oil (1.24 g, 61.08%).

[0210] MS:(ESI,pos.ion)m / z:771.3811[M+H] +

[0211] Step 11: (S)-tert-Butyl 7-(4-((2-((1-(4-(4-hydroxynaphthalen-1-yl)phenyl)-3-methoxy-3-oxopropyl)amino)-2-oxoethyl)amino)-4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (1-8)

[0212] To a clean 100 mL single-necked flask was added tert-butyl (S)-7-(4-((2-((1-(4-(4-(benzyloxy)naphthalen-1-yl)phenyl)-3-methoxy-3-oxopropyl)amino)-2-oxoethyl)amino)-4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (1.23 g, 1.60 mmol), methanol (18.5 mL), and 10% Pd / C (0.123 g). The mixture was evacuated and replaced with hydrogen. The reaction was allowed to proceed at room temperature under a hydrogen atmosphere. Post-treatment: filtration, concentration of the filtrate under reduced pressure, and purification by column chromatography (DCM / MeOH (v / v) = 40 / 1) afforded the title compound as a yellow fluffy solid (446 mg, 40.92%).

[0213] MS:(ESI,pos.ion)m / z:681.3393[M+H] +

[0214] Step 12: (S)-tert-Butyl 7-(4-((2-((1-(4-(4-((14-azido-3,6,9,12-tetraoxatetradecyl)oxy)naphthalen-1-yl)phenyl)-3-methoxy-3-oxopropyl)amino)-2-oxoethyl)amino)-4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (1-9)

[0215] In a clean 100 mL single-necked flask, (S)-tert-butyl 7-(4-((2-((1-(4-(4-hydroxynaphthalen-1-yl)phenyl)-3-methoxy-3-oxopropyl)amino)-2-oxoethyl)amino)-4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (0.446 g, 0.66 mmol), 14-azido-3,6,9,12-tetradecyl-4-methylbenzenesulfonate (0.547 g, 1.31 mmol), DMF (7 mL), and potassium carbonate (0.226 g, 1.64 mmol) were added and the mixture was heated to 80°C for reaction. Post-treatment: water (30 mL) was added directly, extracted with ethyl acetate (20 mL × 2), the organic phases were combined, washed with saturated brine (20 mL × 4), dried over anhydrous sodium sulfate, filtered, concentrated, and purified by column chromatography (DCM / MeOH (V / V) = 40 / 1) to give the title compound as a yellow oil (0.497 g, 81.92%).

[0216] MS:(ESI,pos.ion)m / z:926.4772[M+H] +

[0217] Step 13: (S)-3-(4-(4-((14-azido-3,6,9,12-tetrahydrotetradecyl)oxy)naphthalen-1-yl)phenyl)-3-(2-(4-(5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)butanamido)acetamido)propanoic acid (1)

[0218] In a clean 50 mL single-necked flask, (S)-tert-butyl 7-(4-((2-((1-(4-(4-((14-azido-3,6,9,12-tetraoxatetradecyl)oxy)naphthalen-1-yl)phenyl)-3-methoxy-3-oxopropyl)amino)-2-oxoethyl)amino)-4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (0.49 g, 0.53 mmol), tetrahydrofuran (7.4 mL), and LiOH (38.01 mg, 1.59 mmol) dissolved in water (7.4 mL) were added. The mixture was reacted at room temperature. After the disappearance of the starting material by TLC, 10% citric acid was added to adjust the pH to 4-5. The mixture was extracted with ethyl acetate (20 mL×3), dried over anhydrous sodium sulfate, filtered, and concentrated to give a white solid.

[0219] The obtained white solid was dissolved in DCM (9.6 mL), TFA (3.89 mL, 52.62 mmol) was added, and the reaction was stirred at room temperature.

[0220] Post-treatment: add saturated sodium bicarbonate solution to adjust the pH to neutral or weak alkaline, add dichloromethane (10 mL × 2) for extraction, and purify by column chromatography (PE / EA (V / V) = 10 / 1) to obtain a light yellow oil (302 mg, 70.23%).

[0221] MS:(ESI,pos.ion)m / z:812.4041[M+H] +

[0222] 1H NMR (600MHz, Methanol-d4) δ8.33(dd,J=8.4,1.2Hz,1H),7.75(d,J=8.4Hz,1H),7.51(d,J=8.2Hz,2H),7.45(ddd,J=8.3,6.7,1.2Hz,1H),7.41-7.3 1(m,4H),7.21(d,J=7.9Hz,1H),6.93(d,J=7.9Hz,1H),6.48(d,J=7.3Hz,1 H),5.34(t,J=4.2Hz,1H),4.36-4.31(m,2H),4.04-3.98(m,2H),3.81-3.7 8(m,2H),3.72-3.69(m,2H),3.66-3.64(m,2H),3.63-3.53(m,8H),3.36- 3.33(m,2H),3.33-3.28(m,4H),2.92-2.63(m,6H),2.55(ddd,J=13.6,7.5 ,3.2Hz,1H),2.37(ddd,J=13.7,10.5,3.6Hz,1H),2.18(dtdd,J=13.7,10. 7,5.6,3.3Hz,1H),2.02(tdd,J=12.3,7.9,4.0Hz,1H),1.87-1.77(m,2H).

[0223] Example 2: (S)-3-(4-(4-((14-azido-3,6,9,12-tetrahydrotetradecyl)oxy)naphthalen-1-yl)phenyl)-3-(2-methyl-2-(4-(5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)butanamido)propanamido)propanoic acid (2)

[0224] Synthesis route:

[0225] Step 1: Methyl (S)-3-(4-(4-(benzyloxy)naphthalen-1-yl)phenyl)-3-((tert-butoxycarbonyl)amino)propanoate (2-1)

[0226] In a clean 250 mL single-necked flask, (S)-methyl 3-(4-bromophenyl)-3-((tert-butoxycarbonyl)amino)propanoate (7.2 g, 20.10 mmol), tetrahydrofuran (144 mL), water (36 mL), 2-(4-(benzyloxy)naphthalen-1-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (7.24 g, 20.10 mmol), potassium phosphate (8.53 g, 40.20 mmol) and XPhos Pd G2 (789.7 mg, 1.01 mmol) were added. The atmosphere was replaced with nitrogen and protected, and the reaction was stirred at room temperature. Post-treatment: ethyl acetate (100 mL) and water (200 mL) were added for separation, the aqueous phase was extracted with ethyl acetate (100 mL × 3), the organic phases were combined, washed with saturated brine (200 mL × 3), dried over anhydrous sodium sulfate, filtered, concentrated under reduced pressure, and purified by column chromatography (PE / EA (V / V) = 2 / 1) to give the title compound as a colorless oily liquid (6.00 g, 58.37%).

[0227] Step 2: (S)-methyl 3-amino-3-(4-(4-(benzyloxy)naphthalen-1-yl)phenyl)propanoate hydrochloride (2-2)

[0228] To a clean 100 mL single-necked flask, add methyl (S)-3-(4-(4-(benzyloxy)naphthalen-1-yl)phenyl)-3-((tert-butoxycarbonyl)amino)propanoate (4.5 g, 8.80 mmol) and a 4 mol / L dioxane hydrochloride solution (44 mL). Stir and react at room temperature. Post-processing: Directly spin dry and use in the next step to obtain a white solid (4.4 g, 100% yield).

[0229] Step 3: Synthesis of methyl (S)-3-(4-(4-(benzyloxy)naphthalen-1-yl)phenyl)-3-(2-((tert-butoxycarbonyl)amino)-2-methylpropionamido)propanoate (2-3)

[0230] In a clean 250 mL single-necked flask, (S)-methyl 3-amino-3-(4-(4-(benzyloxy)naphthalen-1-yl)phenyl)propanoate hydrochloride (4.40 g, 9.82 mmol), DMF (66 mL), N-tert-butoxycarbonyl-2-methylalanine (2.99 g, 14.73 mmol), HATU (7.47 g, 19.64 mmol), and DIPEA (6.35 g, 49.10 mmol) were added in sequence and the reaction was stirred at room temperature. Post-treatment: ethyl acetate (100 mL) and water (300 mL) were added for separation, the aqueous phase was extracted with ethyl acetate (100 mL × 2), the organic phases were combined, washed with saturated brine (300 mL × 3), dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure and purified by column chromatography (PE / EA (V / V) = 2 / 1) to give the title compound as a colorless oily liquid (5.50 g, 93.86%).

[0231] MS:(ESI,pos.ion)m / z:597.2989[M+H] +

[0232] Step 4: (S)-methyl 3-(2-amino-2-methylpropionamido)-3-(4-(4-(benzyloxy)naphthalen-1-yl)phenyl)propanoate hydrochloride (2-4)

[0233] To a clean 250 mL single-necked flask, add (S)-methyl 3-(4-(4-(benzyloxy)naphthalen-1-yl)phenyl)-3-(2-((tert-butoxycarbonyl)amino)-2-methylpropionamido)propanoate (5.5 g, 9.22 mmol) and a 4 mol / L dioxane hydrochloride solution (46 mL). Stir and react at room temperature. Post-processing: Directly spin dry and use in the next step to obtain a brown solid (5 g, 100% yield).

[0234] Step 5: (S)-tert-Butyl 7-(4-((1-((1-(4-(benzyloxy)naphthyl-1-yl)phenyl)-3-methoxy-3-oxopropyl)amino)-2-methyl-1-oxopropan-2-yl)amino)-4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (2-5)

[0235] Compound 1-5 (4-(8-(tert-Butyloxycarbonyl)-5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)butanoic acid, 2.10 g, 6.55 mmol), DMF (21 mL) and HATU (4.98 g, 13.1 mmol) were added to a clean 250 mL single-necked flask. DIPEA (4.23 g, 32.75 mmol) was added dropwise under ice bath. After addition, the mixture was returned to room temperature and stirred for 30 min. Then, (S)-3-(2-amino-2-methylpropionamido)-3-(4-(4-(benzyloxy)naphthalen-1-yl)phenyl)propanoic acid methyl ester hydrochloride (5 g, 9.38 mmol) dissolved in DMF (21 mL) was added dropwise under ice bath and stirred for reaction at room temperature. Post-treatment: ethyl acetate (100 mL) and water (200 mL) were added for separation, the aqueous phase was extracted with ethyl acetate (100 mL × 2), the organic phases were combined, washed with saturated brine (200 mL × 3), dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure and purified by column chromatography (PE / EA (V / V) = 2 / 1) to give the title compound as a colorless oily liquid (2.7 g, 51.53%).

[0236] MS:(ESI,pos.ion)m / z:799.4177[M+H] +

[0237] Step 6: (S)-tert-Butyl 7-(4-((1-((1-(4-(4-(4-hydroxynaphthalen-1-yl)phenyl)-3-methoxy-3-oxopropyl)amino)-2-methyl-1-oxopropan-2-yl)amino)-4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (2-6)

[0238] To a clean 100 mL single-necked flask was added tert-butyl (S)-7-(4-((1-((1-(4-(benzyloxy)naphthalen-1-yl)phenyl)-3-methoxy-3-oxopropyl)amino)-2-methyl-1-oxopropan-2-yl)amino)-4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (2.7 g, 3.38 mmol), methanol (54 mL), and 10% Pd / C (0.81 g). The atmosphere was replaced with hydrogen and the reaction was stirred at room temperature. Post-treatment: After filtration through a pad of Celite, the filtrate was concentrated under reduced pressure and purified by column chromatography (PE / EA (V / V) = 2 / 1) to obtain the title compound as a colorless oily liquid (1.74 g, 72.5%).

[0239] MS:(ESI,pos.ion)m / z:709.3635[M+H] +

[0240] Step 7: (S)-tert-Butyl 7-(4-((1-((1-(4-(4-((14-azido-3,6,9,12-tetraoxatetradecyl)oxy)naphthalen-1-yl)phenyl)-3-methoxy-3-oxopropyl)amino)-2-methyl-1-oxopropan-2-yl)amino)-4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (2-7)

[0241] In a clean 100 mL single-necked flask were added (S)-tert-butyl 7-(4-((1-((1-(4-(4-(4-hydroxynaphthalen-1-yl)phenyl)-3-methoxy-3-oxopropyl)amino)-2-methyl-1-oxopropan-2-yl)amino)-4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (1.74 g, 2.45 mmol), DMF (26 mL), 14-azido-3,6,9,12-tetraoxatetradecyl 4-methylbenzenesulfonate (1.23 g, 2 .95 mmol), potassium carbonate (848.11 mg, 6.14 mmol) was added at 0°C, and the temperature was raised to 80°C with stirring for reaction. Post-treatment: ethyl acetate (30 mL) and water (120 mL) were added for separation, the aqueous phase was extracted with ethyl acetate (30 mL × 3), the organic phases were combined, washed with saturated brine (120 mL × 3), dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure and purified by column chromatography (DCM / MeOH (V / V) = 40 / 1) to obtain the title compound as a colorless oily liquid (2.00 g, 85.47%).

[0242] MS:(ESI,pos.ion)m / z:954.5011[M+H] +

[0243] Step 8: (S)-3-(4-(4-((14-azido-3,6,9,12-tetraoxatetradecyl)oxy)naphthalen-1-yl)phenyl)-3-(2-(4-(8-(tert-butyloxycarbonyl)-5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)butanamido)-2-methylpropanamido)propanoic acid (2-8)

[0244] In a clean 100 mL single-necked flask, (S)-tert-butyl 7-(4-((1-((1-(4-(4-((14-azido-3,6,9,12-tetraoxatetradecyl)oxy)naphthalen-1-yl)phenyl)-3-methoxy-3-oxopropyl)amino)-2-methyl-1-oxopropan-2-yl)amino)-4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (2.0 g, 2.10 mmol) and tetrahydrofuran (30 mL) were added. Lithium hydroxide (150.59 mg, 6.29 mmol) was dissolved in water (30 mL) and added to the reaction system. The reaction was stirred at room temperature. Post-treatment: 10% citric acid was added to adjust the pH to 4-6, ethyl acetate (50 mL) and water (200 mL) were added to extract the liquid, the aqueous phase was extracted with ethyl acetate (50 mL × 3), the organic phases were combined, washed with saturated brine (200 mL × 3), dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure and purified by column chromatography (DCM / MeOH (V / V) = 10 / 1) to give the title compound as a colorless oily liquid (1.1 g, 55.84%).

[0245] MS:(ESI,pos.ion)m / z:940.4873[M+H] +

[0246] Step 9: (S)-3-(4-(4-((14-azido-3,6,9,12-tetraoxatetradecyl)oxy)naphthalen-1-yl)phenyl)-3-(2-methyl-2-(4-(5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)butanamido)propanamido)propanoic acid (2)

[0247] In a clean 100 mL single-necked flask, (S)-3-(4-(4-((14-azido-3,6,9,12-tetraoxatetradecyl)oxy)naphthalen-1-yl)phenyl)-3-(2-(4-(8-(tert-butoxycarbonyl)-5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)butanamido)-2-methylpropanamido)propanoic acid (1.10 g, 1.17 mmol), dichloromethane (22 mL) and trifluoroacetic acid (13.34 g, 117.01 mmol) were added and the reaction was stirred at room temperature. Post-treatment: After adjusting the pH to neutral with saturated sodium bicarbonate solution, dichloromethane (20 mL) and water (50 mL) were added for separation, the aqueous phase was extracted with dichloromethane (50 mL×3), the organic phases were combined, washed with saturated brine (50 mL×3), dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure and purified by column chromatography (DCM / MeOH (V / V) = 20 / 1) to give the title compound as a colorless oily solid (532 mg, 54.13%).

[0248] MS:(ESI,pos.ion)m / z:840.4305[M+H] +

[0249] 1 H NMR (600MHz, CDCl3) δ10.86 (s, 1H), 9.44 (d, J = 8.2Hz, 1H), 8.35-8.32 (m, 1H), 7.92 (d ,J=8.4Hz,1H),7.56(d,J=8.0Hz,2H),7.46(ddd,J=8.2,6.8,1.1Hz,1H),7.42-7.40( m,1H),7.38(d,J=8.2Hz,2H),7.29(s,0.5H),7.27(s,0.5H),7.21(d,J=7.2Hz,1H),6 .85(d,J=7.9Hz,1H),6.26(d,J=7.3Hz,1H),5.77(s,1H),5.32(d,J=5.4Hz,1H),4.36- 4.32(m,2H),4.05-4.01(m,2H),3.83(dd,J=5.6,3.9Hz,2H),3.73(dd,J=5.6,3.9Hz, 2H),3.70(dd,J=3.6,1.8Hz,2H),3.68-3.61(m,8H),3.41(d,J=4.5Hz,2H),3.39-3.35 (m,2H),3.02-2.86(m,4H),2.68(t,J=6.0Hz,2H),2.43-2.39(m,1H),2.36-2.33(m,1 H),2.07(tdd,J=17.4,10.2,7.0Hz,2H),1.89-1.84(m,2H),1.70(s,3H),1.58(s,3H).

[0250] Example 3: (S)-methyl 3-(4-(4-((14-azido-3,6,9,12-tetrahydrotetradecyl)oxy)naphthalen-1-yl)phenyl)-3-((2-((2-methoxyethyl)(4-(5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)butyl)amino)ethyl)amino)propanoate (3)

[0251] Synthesis route:

[0252] Step 1: tert-Butyl 7-(4-hydroxybutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (3-9-2)

[0253] To a clean 250 mL single-necked bottle, add tert-butyl 7-(4-ethoxy-4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (5.00 g, 14.35 mmol) and dissolve in anhydrous THF (50 mL). Add 2 mol / L LiBH4 in tetrahydrofuran (17.9 mL) dropwise at 0°C. After addition, bring the mixture to room temperature for reaction. Workup: Quench the mixture by dropwise addition of saturated ammonium chloride solution at 0°C. Extract with DCM (80 mL x 2). Combine the organic phases, dry over anhydrous sodium sulfate, and filter. Purify by column chromatography (DCM / MeOH (v / v) = 20 / 1) to afford the compound as a colorless oil (3.3 g, 75%).

[0254] Step 2: tert-Butyl 7-(4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (3-9)

[0255] To a clean 250 mL single-necked bottle, tert-butyl 7-(4-hydroxybutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (3.00 g, 9.79 mmol) was added and dissolved in DCM (30 mL). Dess-Martin periodinane (DMP, 4.98 g, 11.74 mmol) dissolved in DCM (30 mL) was slowly added dropwise. After addition, the mixture was stirred at room temperature for 5 h. Post-treatment: filtration, the organic phase was washed with saturated sodium chloride solution (40 mL), dried over anhydrous sodium sulfate, and purified by column chromatography (PE / EA (v / v) = 1 / 1) to obtain the compound as a yellow oil (1.74 g, 58.39%).

[0256] Step 3: (2-Methoxyethyl)glycine methyl ester (3-2)

[0257] To a clean 250 mL single-necked flask, add 2-methoxyethane-1-amine (7.86 g, 104.6 mmol) and potassium carbonate (29 g, 209.18 mmol). Dissolve the mixture in anhydrous THF (30 mL). Add anhydrous THF (30 mL) dropwise at 0°C to dissolve methyl 2-bromoacetate (8 g, 52.3 mmol). After addition, move the mixture to room temperature and allow to react overnight. Post-treatment: Filtration and purification by column chromatography (DCM / MeOH (v / v) = 20 / 1) afforded the compound as a colorless liquid (6 g, 77.9%).

[0258] Step 4: 2-((2-methoxyethyl)amino)1-ethanol (3-3)

[0259] To a clean 250 mL three-necked flask, add (2-methoxyethyl)glycine methyl ester (5.85 g, 39.77 mmol) and dissolve in anhydrous THF (46.8 mL). Under N2 protection, slowly add 2.5 mol / L LiAlH4 tetrahydrofuran solution (47.7 mL, 119.31 mmol) dropwise at 0°C. After addition, move to room temperature and stir for 4 h. Workup: Quench the mixture with water (4.7 mL) at 0°C, stir for 10 min, then add 1 mol / L NaOH solution (4.7 mL). Stir for 15 min, then add water (4.7 mL). Extract with EA (60 mL x 2), dry over anhydrous sodium sulfate, filter, and purify by column chromatography (DCM / MeOH (v / v) = 10 / 1) to obtain the compound (2.49 g, 52.2%) as a brown liquid.

[0260] Step 5: (9H-fluoren-9-yl)methyl(2-hydroxyethyl)(2-methoxyethyl)carbamate (3-4)

[0261] To a clean 100 mL single-necked bottle, add 2-((2-methoxyethyl)amino)1-ethanol (1.64 g, 13.76 mmol) and dissolve it in acetonitrile (16 mL). Then, add DIPEA (889.38 mg, 6.88 mmol). Slowly add Fmoc-Cl (4.27 g, 16.52 mmol) dissolved in acetonitrile (16 mL) dropwise. Stir at room temperature overnight. Post-treatment: Purification by column chromatography (PE / EA (v / v) = 1 / 1) afforded the compound as a yellow oil (2.8 g, 59.57%).

[0262] Step 6: (9H-fluoren-9-yl)methyl(2-methoxyethyl)(2-oxoethyl)carbamate (3-5)

[0263] To a clean 100 mL single-necked flask, (9H-fluoren-9-yl)methyl(2-hydroxyethyl)(2-methoxyethyl)carbamate (2.80 g, 8.20 mmol) was added and dissolved in DCM (20 mL). Dess-Martin periodinane (DMP, 4.52 g, 10.66 mmol) was added portionwise at 0°C. After addition, the mixture was stirred at room temperature for 6 h. Post-treatment: filtration, washing with saturated sodium chloride solution (20 mL x 3), drying the organic phase over anhydrous sodium sulfate, and purification by column chromatography (PE / EA (v / v) = 1 / 1) afforded the compound as a yellow oil (1.5 g, 54%).

[0264] Step 7: Methyl (S)-3-((2-((((9H-fluoren-9-yl)methoxy)carbonyl)(2-methoxyethyl)amino)ethyl)amino)-3-(4-(4-(benzyloxy))1-naphthyl)phenyl)propanoate (3-6)

[0265] In a clean 100 mL single-necked bottle, (9H-fluoren-9-yl)methyl(2-methoxyethyl)(2-oxoethyl)carbamate (1.50 g, 4.42 mmol) and compound 2-2 ((S)-3-amino-3-(4-(4-(benzyloxy)naphthalen-1-yl)phenyl)propanoic acid methyl ester hydrochloride, 2.36 g, 5.28 mmol) were added and dissolved in methanol (30 mL). AcOH (132.71 mg, 2.21 mmol) was added dropwise. After stirring at room temperature for 0.5 h, NaBH(AcO)3 (1.87 g, 8.84 mmol) was added at 0°C. After the addition was complete, the mixture was moved to room temperature and stirred for reaction overnight. Post-treatment: saturated sodium bicarbonate solution was added dropwise at 0°C to quench the reaction, extracted with DCM (30 mL×2), dried over anhydrous sodium sulfate, filtered, and purified by column chromatography (DCM / MeOH (V / V) = 20 / 1) to give a white solid compound (2.0 g, 61.5%).

[0266] Step 8: Methyl (S)-3-((2-((((9H-fluoren-9-yl)methoxy)carbonyl)(2-methoxyethyl)amino)ethyl)(tert-butoxycarbonyl)amino)-3-(4-(4-(benzyloxy)naphthalen-1-yl)phenyl)propanoate (3-7)

[0267] To a clean 100 mL single-necked bottle was added methyl (S)-3-((2-((((9H-fluoren-9-yl)methoxy)carbonyl)(2-methoxyethyl)amino)ethyl)amino)-3-(4-(4-(benzyloxy))1-naphthyl)phenyl)propanoate (2.0 g, 2.72 mmol) and dissolved in THF (10 mL). Sodium bicarbonate (685.86 mg, 8.16 mmol) dissolved in water was added, and the mixture was stirred at room temperature for 0.5 h. Boc2O (1.78 g, 8.16 mmol) was added, and the mixture was stirred at room temperature overnight. Post-treatment: EA (20 mL) was added for extraction and separation. 10% citric acid solution (20 mL) was added to the organic phase, and the mixture was stirred for 0.5 h. The mixture was separated, dried over anhydrous sodium sulfate, filtered, and purified by column chromatography (PE / EA (v / v) = 3 / 1) to obtain the compound as a white solid (2.0 g, 88.1%).

[0268] Step 9: (S)-methyl 3-(4-(4-(benzyloxy)naphthalen-1-yl)phenyl)-3-((tert-butoxycarbonyl)(2-((2-methoxyethyl)amino)ethyl)amino)propanoate (3-8)

[0269] Methyl (S)-3-((2-((((9H-fluoren-9-yl)methoxy)carbonyl)(2-methoxyethyl)amino)ethyl)(tert-butoxycarbonyl)amino)-3-(4-(4-(benzyloxy)naphthalen-1-yl)phenyl)propanoate (2.0 g, 2.40 mmol) was added to a clean 100 mL single-necked bottle and dissolved with DCM (30 mL). DEA (30 mL) was then added and stirred at room temperature overnight. Post-treatment: purification by column chromatography (DCM / MeOH (v / v) = 20 / 1) afforded the compound as a colorless oil (1.3 g, 88.44%).

[0270] Step 10: Tert-butyl (S)-7-(4-((2-((1-(4-(4-(benzyloxy)naphth-1-yl)phenyl)-3-methoxy-3-oxopropyl)(tert-butoxycarbonyl))amino)ethyl)(2-methoxyethyl)amino)butyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (3-10)

[0271] In a clean 100 mL single-necked bottle, (S)-methyl 3-(4-(4-(benzyloxy)naphth-1-yl)phenyl)-3-((tert-butoxycarbonyl)(2-((2-methoxyethyl)amino)ethyl)amino)propanoate (1.3 g, 2.12 mmol) and tert-butyl 7-(4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (839.50 mg, 2.76 mmol) were added and dissolved in methanol (26 mL). AcOH (63.70 mg, 1.06 mmol) was added dropwise. After stirring at room temperature for 0.5 h, NaBH(AcO)3 (899.27 mg, 4.24 mmol) was added and stirred at room temperature overnight. Post-treatment: quenched by adding saturated sodium bicarbonate solution, extracted with DCM (30 mL), dried over anhydrous sodium sulfate, filtered, and purified by column chromatography (DCM / MeOH (V / V) = 40 / 1) to obtain a light yellow oily compound (1.34 g, 69.9%).

[0272] MS:(ESI,pos.ion)m / z:901.516[M+H] +

[0273] Step 11: Tert-butyl (S)-7-(4-((2-((tert-butoxycarbonyl)(1-(4-(4-hydroxynaphthalen-1-yl)phenyl)-3-methoxy-3-oxopropyl)amino)ethyl)(2-methoxyethyl)amino)butyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (3-11)

[0274] To a clean 100 mL single-necked bottle was added tert-butyl (S)-7-(4-((2-((1-(4-(4-(benzyloxy)naphthalen-1-yl)phenyl)-3-methoxy-3-oxopropyl)(tert-butoxycarbonyl))amino)ethyl)(2-methoxyethyl)amino)butyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (1.18 g, 1.31 mmol) and dissolved in methanol (23.6 mL). Pd / C (472 mg, 0.4 g / g) was added, and the mixture was stirred at room temperature under a H2 atmosphere overnight. Post-treatment: filtration through a pad of Celite and purification by column chromatography (DCM / MeOH (v / v) = 20 / 1) afforded the compound as a pale yellow solid (0.95 g, 89.45%).

[0275] Step 12: Tert-butyl (S)-7-(4-((2-((1-(4-(4-((14-azido-3,6,9,12-tetrahydrotetradecyl)oxy)naphthalen-1-yl))phenyl)-3-methoxy-3-oxopropyl)(tert-butoxycarbonyl)amino)ethyl)(2-methoxyethyl)amino)butyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (3-12)

[0276] In a clean 100 mL single-necked bottle, tert-butyl (S)-7-(4-((2-((tert-butoxycarbonyl)(1-(4-(4-hydroxynaphthalen-1-yl)phenyl)-3-methoxy-3-oxopropyl)amino)ethyl)(2-methoxyethyl)amino)butyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (950 mg, 1.17 mmol) and 14-azido-3,6,9,12-tetrahydrotetradecyl 4-methylbenzenesulfonate (978.02 mg, 2.34 mmol) were added and dissolved in DMF (9.5 mL). Potassium carbonate (485.66 mg, 3.51 mmol) was added at 0°C. After the addition, the temperature was raised to 80°C and the reaction was stirred for 6 h. Post-treatment: cool to room temperature, add water (50 mL) and EA (20 mL) to extract and separate the liquids, wash the organic phase with water (20 mL × 3), dry over anhydrous sodium sulfate, filter, and purify by column chromatography (DCM / MeOH (V / V) = 20 / 1) to give a light yellow solid compound (1.1 g, 88.7%).

[0277] Step 13: (S)-3-(4-(4-((14-azido-3,6,9,12-tetrahydrotetradecyl)oxy)naphthalen-1-yl)phenyl)-3-((tert-butoxycarbonyl)(2-((4-(8-(tert-butoxycarbonyl)-5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)butyl)(2-methoxyethyl)amino)ethyl)amino)propanoic acid (3-13)

[0278] In a clean 100 mL single-necked bottle, tert-butyl (S)-7-(4-((2-((1-(4-(4-((14-azido-3,6,9,12-tetrahydrotetradecyl)oxy)naphthalen-1-yl))phenyl)-3-methoxy-3-oxopropyl)(tert-butoxycarbonyl)amino)ethyl)(2-methoxyethyl)amino)butyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (1.1 g, 1.04 mmol) was added and dissolved in THF (14.5 mL). LiOH (74.81 mg, 3.12 mmol) dissolved in water (16.5 mL) was added dropwise at 0°C. After the addition, the reaction was stirred at room temperature for 4 h. Post-treatment: add 10% citric acid aqueous solution to adjust the pH to about 4, extract with DCM (20 mL×3), dry over anhydrous sodium sulfate, filter, concentrate and dry to obtain a white solid compound (1.09 g, yield 100%).

[0279] Step 14: (S)-3-(4-(4-((14-azido-3,6,9,12-tetrahydrotetradecyl)oxy)naphthalen-1-yl)phenyl)-3-((2-((2-methoxyethyl))(4-(5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)butyl)amino)ethyl)amino)propanoic acid (3)

[0280] In a clean 50 mL single-necked bottle, (S)-3-(4-(4-((14-azido-3,6,9,12-tetrahydrotetradecyl)oxy)naphthalen-1-yl)phenyl)-3-((tert-butoxycarbonyl)(2-((4-(8-(tert-butoxycarbonyl)-5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)butyl)(2-methoxyethyl)amino)ethyl)amino)propanoic acid (500 mg, 0.48 mmol) was dissolved in DCM (10 mL), and TFA (8.2 g, 7.2 mmol) was added. The reaction was stirred at room temperature for 4 h. Post-treatment: quenching was performed by adding saturated sodium bicarbonate solution, extraction with DCM (20 mL x 2), drying over anhydrous sodium sulfate, filtration, and purification by wet-loading onto a neutral alumina column (DCM / MeOH (v / v) = 15 / 1). A light yellow compound (313 mg, 77.49%) was obtained.

[0281] MS:(ESI,pos.ion)m / z:842.494[M+H] +

[0282] 1H NMR (600MHz, CDCl3) δ11.13(s,1H),8.37(d,J=7.8Hz,1H),7.93(d,J=8.1Hz,1H),7.53(d,J=6.1Hz,2H),7.47(ddd,J=17.0,10 .8,4.0Hz,2H),7.43(d,J=7.4Hz,2H),7.34(d,J=7.8Hz,1H),7.21(d,J=7.2Hz,1H),6.89(d,J=7.9Hz,1H),6.26(d,J=7.2Hz,1 H),4.40-4.35(m,2H),4.16(d,J=9.1Hz,1H),4.07-4.03(m,2H),3.84(dd,J=5.6,3.9Hz,2H),3.75-3.72(m,2H),3.72-3.62(m ,10H),3.46(dd,J=12.2,6.1Hz,4H),3.38(t,J=5.1Hz,2H),3.33(s,3H),2.78-2.54(m,12H),1.98-1.85(m,4H),1.27(s,4H).

[0283] Example 4: (4)

[0284] Synthesis route:

[0285] Step 1: tert-Butyl 3-(2-(2-hydroxyethoxy)ethoxy)propanoate (4-9-2)

[0286] To a clean 50 mL single-necked flask, add 2,2'-oxybis(ethan-1-ol) (2 g, 18.85 mmol) and tert-butyl acrylate (0.725 g, 5.65 mmol). KOH (0.148 g, 2.64 mmol) dissolved in water (0.21 mL) was added dropwise. The reaction was continued at room temperature. Post-treatment: Add water (20 mL), extract with ethyl acetate (30 mL), wash the organic phase with saturated brine (30 mL x 4), dry over anhydrous sodium sulfate, filter, and purify by column chromatography (PE / EA (v / v) = 1 / 2) to obtain the title compound as a colorless oil (1.30 g, 98.81%).

[0287] MS:(ESI,pos.ion)m / z:179.0928[M-56+H] +

[0288] Step 2: tert-Butyl 3-(2-(2-(toluenesulfonyloxy)ethoxy)ethoxy)propanoate (4-9-3)

[0289] To a clean 50 mL single-necked flask were added tert-butyl 3-(2-(2-hydroxyethoxy)ethoxy)propanoate (0.4 g, 1.71 mmol), DMAP (20.86 mg, 0.17 mmol), triethylamine (0.345 g, 3.41 mmol), and DCM (4 mL). p-Toluenesulfonyl chloride (0.488 g, 2.51 mmol) was added at 0°C. After addition, the reaction was stirred at room temperature. Workup: Water (30 mL) was added, and the mixture was extracted with DCM (30 mL). The organic phase was dried over anhydrous sodium sulfate, filtered, and purified by column chromatography (PE / EA (v / v) = 2 / 1) to afford the title compound as a pale yellow oil (0.615 g, 92.76%).

[0290] MS:(ESI,pos.ion)m / z:333.1023[M-56+H] +

[0291] Step 3: 3-(2-(2-(Toluenesulfonyloxy)ethoxy)ethoxy)propanoic acid (4-9-4)

[0292] To a clean 50 mL single-necked flask, add tert-butyl 3-(2-(2-(tosyloxy)ethoxy)ethoxy)propanoate (615 mg, 1.58 mmol), DCM (8 mL), and TFA (1.44 g, 12.63 mmol) and stir at room temperature overnight. Post-treatment: Add water (10 mL), extract with DCM (20 mL), and wash the organic phase with saturated brine (10 mL x 2), dry over anhydrous sodium sulfate, filter, and concentrate to afford the title compound as a yellow oil (0.531 g, 100%).

[0293] MS: (ESI,pos.ion)m / z: 350.1339[M+H2O] +

[0294] Step 4: Benzyl 3-(2-(2-(toluenesulfonyloxy)ethoxy)propionate (4-9-5)

[0295] To a 50 mL single-necked bottle, 3-(2-(2-(tosyloxy)ethoxy)ethoxy)propanoic acid (0.8 g, 2.41 mmol), benzyl alcohol (0.312 g, 2.89 mmol), and DCM (8 mL) were added. After stirring at room temperature to dissolve, EDCI (0.55 g, 2.89 mmol) and DMAP (29.41 mg, 0.241 mmol) were added. The reaction was allowed to proceed at room temperature under nitrogen. Post-treatment: DCM (10 mL) and saturated brine (20 mL) were added for extraction. The organic phase was dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure. Purification by column chromatography (PE / EA (v / v) = 1 / 1) afforded the title compound as a colorless oil (0.744 g, 72.94%).

[0296] MS:(ESI,pos.ion)m / z:440.1845[M+H2O] +

[0297] Step 5: (S)-7-((2-)((1-(4-(2-(2-(3-)(benzyloxy)3-oxopropoxy)ethoxy)naphthalen-1-yl)phenyl)-3-methoxy-3-oxopropyl(amino)-4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (4-9-6)

[0298] In a 50 mL single-necked bottle, tert-butyl (S)-7-((2-((4-(4-hydroxynaphthalen-1-yl)phenyl)-3-methoxy-3-oxoethyl)amino)-4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (0.1 g, 0.147 mmol), benzyl 3-(2-(toluenesulfonyloxy)ethoxy)propanoate (74.47 mg, 0.176 mmol), D To MF (1.5 mL), potassium carbonate (50.75 mg, 0.367 mmol) was added to the mixture at 0°C until the addition was complete, and the mixture was allowed to react at 80°C. Post-treatment: 20 mL of water and 15 mL of ethyl acetate were added to extract the separated liquid. The organic phase was washed with saturated brine (20 mL × 3), dried over anhydrous sodium sulfate, filtered, and purified by column chromatography (DCM / MeOH (v / v) = 30 / 1) to obtain the title compound as a colorless oil (83 mg, 60.58%).

[0299] MS:(ESI,pos.ion)m / z:931.4532[M+H] +

[0300] Step 6: (S)-3-(2-)(4-(4-(1-)(2-(4-(8-(tert-Butoxycarbonyl)-5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)butyrylamino))-3-methoxy-3-oxypropyl)phenyl)naphthalen-1-yl)oxy(ethoxy)ethoxy)propanoic acid (4-9)

[0301] To a clean 50 mL single-necked flask was added (S)-7-((2-)((1-(4-(2-(2-(3-)(benzyloxy)3-oxopropoxy)ethoxy)naphthalen-1-yl)phenyl)-3-methoxy-3-oxopropyl(amino)-4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (83 mg, 89.14 μmol), methanol (1.25 mL), and 10% palladium on carbon (8 mg, 0.1 g / g). The atmosphere was replaced with hydrogen by vacuum, and the reaction was allowed to proceed at room temperature under a hydrogen atmosphere. Post-treatment: purification by column chromatography (DCM / MeOH (v / v) = 30 / 1) gave the title compound as an off-white solid (62.80 mg, 83.77%).

[0302] MS:(ESI,pos.ion)m / z:841.4142[M+H] +

[0303] Step 7: Di-tert-butyl 3,3'-((2-amino-2-((3-(tert-butoxy)-3-oxopropoxy)methyl)propane-1,3-diyl)bis(oxy)dipropionate (4-2)

[0304] To a clean 500 mL two-necked flask, add 2-amino-2-(hydroxymethyl)propanediol (10 g, 82.55 mmol) and DMSO (33 mL). Add 5 mol / L aqueous sodium hydroxide solution (3.32 mL, 16.51 mmol) at 15°C. Add tert-butyl acrylate (66.66 g, 520.08 mmol) dropwise under N2 protection. After completion, transfer the mixture to room temperature for reaction. Post-treatment: Add water (1 L) and ethyl acetate (0.5 L) for extraction. Wash the organic phase with saturated brine (150 mL x 2), dry over anhydrous sodium sulfate, filter, and purify by column chromatography (DCM / MeOH (v / v) = 50 / 1) to obtain the title compound as a colorless oil (21.54 g, 51.60%).

[0305] MS:(ESI,pos.ion)m / z:506.3344[M+H] +

[0306] Step 8: tert-Butyl 7-(4-ethoxy-4-oxobutyl)-3,4-dihydro-1,8-naphthyridine-1(2H)-carboxylate (4-3)

[0307] To a clean 500 mL three-necked flask was added di-tert-butyl 3,3'-((2-amino-2-((3-(tert-butoxy)-3-oxopropoxy)methyl)propane-1,3-diyl)bis(oxy)dipropionate (12 g, 23.73 mmol), tetrahydrofuran (48 mL), and Fmoc-Osu (11.21 g, 33.22 mmol). The reaction was allowed to proceed at room temperature. Post-treatment: purification by column chromatography (PE / EA (v / v) = 6 / 1) afforded the title compound as a colorless oil (14.21 g, 82.28%).

[0308] MS:(ESI,pos.ion)m / z:672.3440[M-56+H] +

[0309] Step 9: 3,3-((2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino)-2-((2-carboxyethoxy)methyl)propane-1,3-diyl)bis(oxy))dipropanoic acid (4-4)

[0310] Di-tert-butyl 3,3-((2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino)-2-((3-(tert-butoxy)-3-oxopropoxy)methyl)propane-1,3-diyl)bis(oxy))dipropionate (14.2 g, 19.51 mmol) was weighed into a clean 500 mL single-necked bottle and dissolved in DCM (71.05 mL). TFA (71.05 mL) was added and the reaction was stirred at room temperature for 3 h. Post-treatment: Concentrate under reduced pressure to constant weight to obtain a yellow oil (10.92 g, 100% yield).

[0311] MS:(ESI,pos.ion)m / z:560.221[M+H] +

[0312] Step 10: (9H-fluoren-9-yl)methyl di-tert-butyl (9-(12,12-dimethyl-5,10-dioxo-2,11-dioxa-6,9-diazatridecyl)-4,14-dioxo-7,11-dioxa-3,15-diazaheptadecan-1,9,17-triyl) tricarbamate (4-5)

[0313] In a clean 500 mL single-necked bottle, 3,3-((2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino)-2-((2-carboxyethoxy)methyl)propane-1,3-diyl)bis(oxy))dipropionic acid (10.90 g, 19.48 mmol) and HATU (37.04 g, 97.4 mmol) were weighed and dissolved in DCM (150 mL). After stirring at room temperature for 1 h, tert-butyl (2-aminoethyl)carbamate (15.6 g, 97.4 mmol) was added at 0°C, followed by the dropwise addition of DIPEA (25.18 g, 194.8 mmol). After completion of the addition, the mixture was stirred at room temperature for 3 h. Post-treatment: saturated sodium bicarbonate solution (100 mL) was added for extraction and separation, and the organic phase was separated. The organic phase was washed with saturated sodium chloride solution (100 mL × 2), dried over anhydrous sodium sulfate, filtered, and purified by column chromatography (DCM / MeOH (V / V) = 20 / 1) to give a colorless oily compound (16.2 g, 84.33%).

[0314] MS:(ESI,pos.ion)m / z:986.553[M+H] +

[0315] Step 11: (9H-fluoren-9-yl)methyl(1,17-diamino-9-((3-((2-aminoethyl)amino)-3-oxopropoxy)methyl)-4,14-dioxo-7,11-dioxa-3,15-diazaheptadecan-9-yl)carbamate hydrochloride (4-6)

[0316] To a clean 500 mL single-necked bottle, add (9H-fluoren-9-yl)methyl di-tert-butyl (9-(12,12-dimethyl-5,10-dioxo-2,11-dioxa-6,9-diazatridecyl)-4,14-dioxo-7,11-dioxa-3,15-diazaheptadecan-1,9,17-triyl) tricarbamate (16.20 g, 16.43 mmol). Dissolve the mixture in 1,4-dioxane (64.8 mL). Add 4 mol / L hydrochloric acid in dioxane (64.8 mL). Stir at room temperature for 1.5 h. Post-treatment: Concentrate under reduced pressure to constant weight to obtain the compound as a white solid (11.27 g, 95.02%).

[0317] MS:(ESI,pos.ion)m / z:686.38[M+H] +

[0318] Step 12: (9H-fluoren-9-yl)methyl di-tert-butyl (19-(22,22-dimethyl-5,10,20-trioxo-2,13,16,21-tetraoxa-6,9,19-triazatricosyl))-9,14,24,29-tetraoxo-3,6,17,21,32,35-hexaoxo-10,13,25,28-tetraazahepta(dotriacontane-1,19,37-triyl) tricarbamate (4-7)

[0319] In a clean 500 mL single-necked bottle, 2,2-dimethyl-4-oxo-3,8,11-trioxa-5-aza-14-oleic acid (16.41 g, 59.16 mmol) and HATU (62.4 g, 164.3 mmol) were weighed and dissolved in DCM (220 mL). DIPEA (25.48 g, 197.16 mmol) was added at 0°C and stirred at 0°C for 0.5 h. Then, (9H-fluoren-9-yl)methyl(1,17-diamino-9-((3-((2-aminoethyl)amino)-3-oxopropoxy)methyl)-4,14-dioxo-7,11-dioxa-3,15-diazaheptadecan-9-yl)carbamate (11.27 g, 15.60 mmol) was slowly added at 0°C. After addition, the mixture was stirred at room temperature for 3 h. Post-treatment: saturated sodium bicarbonate solution (150 mL) was added for extraction and separation, and the organic phase was separated. The organic phase was washed with saturated sodium chloride solution (150 mL × 2), dried over anhydrous sodium sulfate, filtered, and purified by column chromatography (DCM / MeOH (V / V) = 10 / 1) to give a brown oily compound (14.79 g, 64.75%).

[0320] MS: (ESI, pos.ion)m / z: 1463.81[M+H] +

[0321] Step 13: (9H-fluoren-9-yl)methyl(1,37-diamino-19-(18-amino-5,10-dioxo-2,13,16-trioxa-6,9-diazaoctadecyl)-9,14,24,29-tetraoxo-3,6,17,21,32,35-hexaoxa-10,13,25,28-tetraazaheptadecan-19-yl)carbamate hydrochloride (4-8)

[0322] In a clean 50 mL single-necked bottle, (9H-fluoren-9-yl)methyl di-tert-butyl (19-(22,22-dimethyl-5,10,20-trioxo-2,13,16,21-tetraoxa-6,9,19-triazatricosyl))-9,14,24,29-tetraoxo-3,6,17,21,32,35-hexaoxo-10,13,25,28-tetraazahepta(dotriacontane-1,19,37-triyl) tricarbamate (1 g, 683.19 μmol) was weighed and dissolved in dioxane (3 mL). Then, 4 mol / L hydrochloric acid solution in dioxane (6 mL) was added and the reaction was stirred at room temperature for 4 h. Post-treatment: Concentration to constant weight afforded the title compound as an off-white solid (1.23 g, 100% yield).

[0323] MS: (ESI, pos.ion)m / z:1163.6813[M+H] +

[0324] Step 14: (4-10)

[0325] In a clean 50 mL single-necked bottle, (S)-3-(2-)(4-(4-(1-)(2-(4-(8-(tert-butoxycarbonyl)-5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)butyrylamino))-3-methoxy-3-oxypropyl)phenyl)naphthalen-1-yl)oxy(ethoxy)ethoxy)propanoic acid (585.52 mg, 0.696 mmol) and HATU (0.882 g, 2.32 mmol) were weighed and dissolved in DCM (9 mL). After stirring at room temperature for 0.5 h, ( To the mixture of 2,7-diamino-19-(18-amino-5,10-dioxo-2,13,16-trioxa-6,9-diazaoctadecyl)-9,14,24,29-tetraoxo-3,6,17,21,32,35-hexaoxa-10,13,25,28-tetraazaheptadecan-19-yl)-9H-fluoren-9-yl)methylcarbamate hydrochloride (225 mg, 0.188 mmol) was added dropwise DIPEA (0.50 g, 3.87 mmol). After addition, the mixture was stirred at room temperature overnight. Post-treatment: the product was washed once with saturated sodium bicarbonate solution and saturated brine solution, dried over anhydrous sodium sulfate, filtered, and purified by column chromatography (DCM / MeOH (v / v) = 12 / 1) to give an off-white solid (559 mg, 82.07%).

[0326] MS:(ESI,pos.ion)m / z:1816.9102[M / 2+2H] +

[0327] Step 15: (4-11)

[0328] In a clean 50 mL single-necked vial, 4-10 (559 mg, 0.154 mmol), DCM (2.24 mL), and DEA (2.24 mL) were weighed and stirred at room temperature for 2 h. Workup: Concentrate under reduced pressure, wet-load, and purify by neutral alumina column chromatography (DCM / MeOH (v / v) = 20 / 1) to afford a yellow oil (457 mg, 87.05%).

[0329] MS:(ESI,pos.ion)m / z:3408.73[M+H] +

[0330] Step 16: (4-12)

[0331] To a clean 50 mL single-necked bottle, 12-azidodecanoic acid (98.94 mg, 0.41 mmol) and HATU (0.364 g, 0.957 mmol) were added and dissolved in DCM (9.32 mL). After stirring at room temperature for 0.5 h, 4-11 (0.466 g, 0.137 mmol) was slowly added at 0°C, followed by dropwise addition of DIPEA (0.21 g, 1.625 mmol). The mixture was stirred at room temperature overnight. Post-treatment: saturated sodium bicarbonate solution (10 mL) and DCM (10 mL) were added for extraction and separation. The organic phase was washed with saturated sodium chloride solution (10 mL), dried over anhydrous sodium sulfate, filtered, and purified by column chromatography (DCM / MeOH (v / v) = 10 / 1) to afford an off-white solid (0.39 g, 78.55%).

[0332] MS:(ESI,pos.ion)m / z:3632.93[M+2H] +

[0333] Step 17: (4)

[0334] To a clean 50 mL single-necked vial, 4-12 (0.39 g, 107.34 μmol) was added and dissolved in THF (3.9 mL). After stirring at room temperature, the mixture was dissolved and LiOH (23.13 mg, 966.06 μmol) dissolved in water (3.9 mL) was added. The mixture was stirred at room temperature overnight. Post-treatment: The pH was adjusted to 4 with 10% citric acid and extracted with a mixed solution of (DCM:MeOH = 6:1) (10 mL x 4). The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to constant weight. The resulting 0.38 g residue was dissolved in dichloromethane (3.9 mL) and TFA (3.9 mL) was added. The mixture was stirred at room temperature for 7 h, concentrated under reduced pressure to constant weight, and purified by reverse-phase column chromatography (acetonitrile:water = 1:1). The mixture was lyophilized to obtain a viscous white solid (203 mg, 55.80%).

[0335] MS:(ESI,pos.ion)m / z:3290.71[M+2H]+

[0336] 1 H NMR(600MHz,MeOD)δ8.35(d,J=8.4Hz,3H),7.76(d,J=8.5Hz,3H),7.55-7.45 (m,12H),7.41(t,J=8.2Hz,9H),7.26(d,J=7.9Hz,3H),6.97(d,J=8.0Hz,3H), 6.60(d,J=7.3Hz,3H),5.51(t,J=7.1Hz,3H),4.37-4.30(m,6H),4.04-4.00( m,6H),3.99(s,2H),3.94(s,2H),3.82-3.77(m,6H),3.76(t,J=6.1Hz,6H),3. 72-3.58(m,24H),3.53(t,J=4.8Hz,12H),3.46(dt,J=6.5,4.8Hz,12H),3.33 (d,J=1.5Hz,8H),3.28(s,12H),2.99-2.90(m,6H),2.78-2.66(m,12H),2.52- 2.37(m,18H),2.34(td,J=7.0,4.0Hz,6H),2.16(t,J=7.5Hz,2H),2.04-1.96 (m,6H),1.93-1.86(m,6H),1.54(dd,J=14.4,7.0Hz,4H),1.34-1.24(m,16H).

[0337] Example 5 Evaluation of Integrin αvβ6 ELISA Binding Assay

[0338] Objective: To evaluate the potential inhibitory effect of compounds on integrin αvβ6 in an ELISA binding assay.

[0339] RCTS-001 was prepared according to Chinese patent CN201880070813.4, and its structure is

[0340] Experimental procedures

[0341] 1. Buffer preparation.

[0342] 2. A flat-bottom 96-well ELISA plate was coated with TGF-β1 in carbonate buffer (80 μL per well) at 4°C overnight.

[0343] 3. Wash: Wash the wells three times with 200 μl of wash buffer per well.

[0344] 4. Block with 150 μl of assay buffer per well for 1 hour at 25°C. Prepare a 3-fold serial dilution of reference CWHM-12 from 100 μM in DMSO for 10 doses, and a 10-fold serial dilution of the compound from 2 mM in DMSO for 10 doses. Prepare two serial dilutions of the reference and test compounds: transfer 1 μl of 100X reference CWHM-12 or test compound to 99 μl of 1X assay buffer. Prepare 2X His-Tag αvβ6 protein in assay buffer.

[0345] 5. Wash: Repeat step 3.

[0346] 6. Add samples: Add 25 μl of 2X HisTagαvβ6 protein and 25 μl of 2X compound dilution to each well, centrifuge the 96-well plate at 1000 rpm for 1 minute, and incubate at 25°C for 1 hour.

[0347] 7. Washing: Repeat step 3.

[0348] 8. Prepare the primary antibody (anti-αv mouse anti-human) by adding 50 μl of primary antibody in buffer to each well and incubate at 25°C for 1 hour.

[0349] 9. Washing: Repeat step 3.

[0350] 10. Prepare secondary peroxidase-conjugated antibody (H+L) by adding 50 μl of secondary peroxidase-conjugated antibody in buffer to each well. Centrifuge the 96-well plate at 1000 rpm for 1 minute and incubate at 25°C for 1 hour.

[0351] 11. Washing: Repeat step 3.

[0352] 12. Add substrate: Add 30 μl of substrate solution to each well, centrifuge the 96-well plate at 1000 rpm for 1 minute, and incubate at 25°C for 40 minutes.

[0353] 13. Stop: Add 30 μl of stop solution to each well and centrifuge the 96-well plate at 1000 rpm for 1 minute.

[0354] 14. Read the fluorescence signal on the plate using the OD450 on the BMG.

[0355] Data Analysis

[0356] The calculation method of inhibition % is as follows:

[0357] ABS: absorbance

[0358] Average absorbance of the positive control across the entire plate

[0359] Average absorbance of the negative control across the entire plate

[0360] Calculate IC50 and plot compound effect-dose curves

[0361] IC50 (dose response - variable slope) was calculated by fitting the % inhibition value and the logarithm of the compound concentration using Graphpad 8.0. Y = Bottom + (Top - Bottom) / (1 + 10^((LogIC50 - X) * Hill Slope))

[0362] X:log of inhibitor concentration;Y:%Inhibition

[0363] Experimental results

[0364] The experimental results show that the integrin ligand compound (1) of the present invention has an IC50 of 2.12 nM, which is better than RCTS-001. Compound (4) and RCTS-001 show the same excellent targeting and inhibitory effects, while compound (3) and compound (2) show better targeting and inhibitory effects. Subsequently, the inventors conducted cell adhesion tests on the integrin ligand compounds (1), (2), (3) and (4) of the present invention, and administered RNAi agents conjugated with the αvβ6 integrin ligand of the present invention to rats, which showed excellent pharmacodynamic activity. Comprehensive evaluation shows that the compounds designed by the present invention have good targeting and inhibitory effects on integrin αvβ6, and have excellent pharmacodynamic activity after further combining with RNAi agents, and the comprehensive evaluation is relatively good.

[0365] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A compound as shown in the following formula I, its tautomer or a pharmaceutically acceptable salt thereof, which is: in, Ring A is selected from optionally substituted C 3-10 Cycloalkyl, 3-10 membered heterocycloalkyl and phenyl; n is an integer from 0 to 7; J is selected from CH or N; X is selected from -CH2-, -C(=O)-; Y is selected from -CH2-, -C(=O)-; Z is selected from OR6, N(R6)2 or SR6; R1 is selected from H, optionally substituted alkyl; R2 is selected from H, optionally substituted alkyl; R3 is selected from aryl optionally substituted by R7, optionally substituted heteroaryl, optionally substituted heterocyclyl, optionally substituted cycloalkyl or R3 comprises a transported molecule; R4 is selected from H, C 1-3 alkyl; R5 is selected from H, C 1-3 alkyl; Each R6 is independently selected from H, optionally substituted alkyl, or R6 comprises a transported molecule; Wherein, the substituents in ring A, R1, R2 and R6 are independently selected from halogen, CF3, OH, NH2, C 1- 6-alkoxy, the number of substituents in each group is independently selected from 1, 2 or 3; R7 is selected from one or more divalent cyclic moieties having 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 carbon atoms optionally substituted with R8, wherein R8 comprises one or more molecules to be transported.

2. The compound according to claim 1, characterized in that in, Said n is 3, X is selected from -CH2-, Y is selected from -CH2-, and Z is selected from OH.

3. The compound according to claim 1, characterized in that in, Said n is 3, X is selected from -C(=O)-, Y is selected from -C(=O)-, and Z is OH.

4. The compound according to claim 1, characterized in that in, The R1 is selected from R2 is selected from H, R3 is selected from phenyl, R4 is selected from H, and R5 is selected from H.

5. The compound according to claim 1, characterized in that in, The R1 is selected from H, R2 is selected from H, R3 is selected from phenyl, R4 is selected from H, and R5 is selected from H.

6. The compound according to claim 1, characterized in that in, The R1 is selected from H, R2 is selected from H, R3 is selected from phenyl, R4 is selected from methyl, and R5 is selected from methyl.

7. The compound according to claim 1, characterized in that in, The ring A is selected from 8. The compound according to claim 1, characterized in that in, The J is selected from N.

9. The compound according to claim 1, characterized in that The divalent cyclic moiety includes a cycloalkyl, cycloalkenyl, aryl, heteroaryl or heterocyclyl, wherein the cycloalkyl is cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or cycloheptyl, the cycloalkenyl is cyclopentenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl or cycloheptenyl, the aryl is phenyl, naphthyl, the heteroaryl is pyridyl, pyrimidinyl, pyridazinyl, pyrrole, pyrazole, imidazole, thiophene, benzothiophene, thiazole, benzothiazole, furan, oxazole, isoxazole, benzofuran, indole, indazole, benzimidazole, oxadiazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, quinolyl, isoquinolyl or quinoxalinyl, and the heterocyclyl is tetrahydrofuran, tetrahydropyran, piperidine, pyrrolidine, dioxane or dioxolane.

10. A compound of the formula, a tautomer thereof, or a pharmaceutically acceptable salt thereof, in, R9 contains the molecule to be transported.

11. The compound according to any one of claims 1 to 10, characterized in that Further comprising a polyethylene glycol linker having 2 to 20 ethylene oxide units.

12. A compound of the following formula, a tautomer thereof or a pharmaceutically acceptable salt thereof, wherein the compound is selected from in The point of attachment to the portion comprising the molecule being transported is indicated.

13. A compound of the following formula, a tautomer thereof or a pharmaceutically acceptable salt thereof, wherein the compound is selected from in The point of attachment to the portion comprising the molecule being transported is indicated.

14. The compound according to any one of claims 1 to 13, characterized in that The molecule being transported is either an active pharmaceutical ingredient or a prodrug.

15. The compound according to any one of claims 1 to 13, characterized in that The molecules transported include small molecules, antibodies, antibody fragments, immunoglobulins, monoclonal antibodies, labels or markers, lipids, natural or modified nucleic acids, natural or modified nucleic acid oligonucleotides, natural or modified nucleic acid polynucleotides, peptides, nucleic acid aptamers, polymers, polyamines, proteins, toxins, vitamins, polyethylene glycol, haptens, digoxigenin, biotin, radioactive atoms or molecules, or fluorophores.

16. The compound according to any one of claims 1 to 13, characterized in that The transported molecule comprises a RNAi agent.

17. A structure, characterized in that It comprises the compound according to any one of claims 1 to 16, a linker and a scaffold, wherein the structure is bound to a molecule to be transported and the compound is an αvβ6 ligand.

18. The structure according to claim 17, characterized in that The structure comprises a monodentate form of the αvβ6 integrin ligand.

19. The structure according to claim 17, characterized in that The structure comprises a bidentate αvβ6 integrin ligand.

20. The structure according to claim 17, characterized in that The structure comprises a tridentate αvβ6 integrin ligand.

21. The structure according to claim 17, characterized in that The structure comprises a tetradentate form of an αvβ6 integrin ligand.

22. The structure according to claim 17, characterized in that The bracket has the following formula: in " represents the RNAi agent, and "αvβ6 ligand" represents the respective ligand structure and linker.

23. A compound as shown in the following formula Ib, its tautomer or a pharmaceutically acceptable salt thereof, wherein the compound is an αvβ6 integrin ligand precursor, comprising the structure: in, Ring A is selected from optionally substituted C 3-10 Cycloalkyl, 3-10 membered heterocycloalkyl and phenyl; n is an integer from 0 to 7; J is selected from CH or N; X is selected from -CH2-, -C(=O)-; Y is selected from -CH2-, -C(=O)-; Z is selected from OR6, N(R6)2 or SR6; R1 is selected from H, optionally substituted alkyl; R2 is selected from H, optionally substituted alkyl; R3 is selected from aryl optionally substituted by R7, optionally substituted heteroaryl, optionally substituted heterocyclyl, optionally substituted cycloalkyl, or R3 comprises a linker conjugated to a reactive group; R4 is selected from H, C 1-3 alkyl; R5 is selected from H, C 1-3 alkyl; Each R6 is independently H, optionally substituted alkyl, or R6 comprises a linker group that is transported or conjugated to a reactive group; Wherein, the substituents in ring A, R1, R2 and R6 are independently selected from halogen, CF3, OH, NH2, C 1- 6-alkoxy, the number of substituents in each group is independently selected from 1, 2 or 3; R7 is selected from a substituent group that is one or more divalent cyclic moieties having 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 carbon atoms optionally substituted with R8, wherein R8 comprises a linking group conjugated to a reactive group.

24. The compound according to claim 23, characterized in that Wherein the linking group is a PEG linker.

25. The compound according to claim 23, characterized in that The PEG linker contains 2-20 PEG units.

26. The compound according to claim 23, characterized in that The reactive group is azide.

27. The compound according to claim 23, characterized in that Wherein the linking group conjugated to the reactive group has the structure: where m is an integer from 2 to 20, and represents the point of attachment to the structure of Formula Ib.

28. An αvβ6 integrin ligand precursor, a tautomer thereof or a pharmaceutically acceptable salt thereof, which is selected from:

29. An αvβ6 integrin ligand precursor, a tautomer thereof or a pharmaceutically acceptable salt thereof, which is selected from:

30. A composition comprising a compound according to any one of claims 1 to 16 or a structure according to any one of claims 17 to 22, and a pharmaceutically acceptable excipient.

31. The composition according to claim 30, characterized in that The compounds are conjugated to oligonucleotide-based compounds capable of inhibiting the expression of target genes in epithelial cells.

32. The composition according to claim 30, characterized in that The compound is conjugated to a RNAi agent capable of inhibiting the expression of a target gene in epithelial cells.

33. The composition according to claim 30, characterized in that The compound is conjugated to a RNAi agent capable of inhibiting the expression of a target gene in bronchiolar epithelial cells.

34. A method of delivering one or more transported molecules to a cell, the method comprising administering to the cell a compound of any one of claims 1-16 or a structure of any one of claims 17-22.

35. A method for delivering one or more transported molecules to a cell or tissue of a subject in vivo, the method comprising administering to the subject a compound of any one of claims 1-16, a structure of any one of claims 17-22, or a composition of any one of claims 30-33.

36. The method according to claim 34 or 35, characterized in that The cells are selected from type I and type II alveolar epithelial cells, goblet cells, secretory epithelial cells, ciliated epithelial cells, corneal and conjunctival epithelial cells, dermal epithelial cells, bile duct epithelial cells, intestinal epithelial cells, ductal epithelial cells, glandular epithelial cells and epithelial tumor carcinomas.

37. The method according to any one of claims 34 to 36, characterized in that: One or more of the transported molecules comprises an oligonucleotide-based compound.

38. The method according to claim 37, characterized in that Wherein the oligonucleotide-based compound is a RNAi agent.

39. A method of inhibiting target gene expression in a cell in vivo, the method comprising administering to a subject an effective amount of a composition comprising an oligonucleotide-based compound conjugated to a compound of any one of claims 1-16.

40. The method according to claim 39, characterized in that The cells are selected from type I and type II alveolar epithelial cells, goblet cells, secretory epithelial cells, ciliated epithelial cells, corneal and conjunctival epithelial cells, dermal epithelial cells, bile duct epithelial cells, intestinal epithelial cells, ductal epithelial cells, glandular epithelial cells and epithelial tumors.

41. The method according to claim 39, characterized in that Wherein the oligonucleotide-based compound is a RNAi agent.

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