HDAC6 inhibitors, methods of making, and uses thereof

Abstract

This application provides a selective HDAC6 inhibitor, its preparation method, and its application, belonging to the field of medicinal chemistry. The selective HDAC6 inhibitor is a compound of Formula I or a pharmaceutically acceptable salt thereof, where R1, R2, R3, R4, R5, R6, and L are as described herein. The compound of Formula I is a highly selective histone deacetylase 6 (HDAC6) inhibitor, which can be used for diseases caused by HDAC6 abnormalities, such as inflammatory diseases (e.g., peritonitis, inflammatory bowel disease, psoriasis) and other diseases.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis, and more specifically, to the field of organic compound synthesis and pharmaceutical application technology, and more specifically to a histone deacetylase 6 inhibitor containing acylhydrazide, its preparation method and its application. Background Technology

[0002] Histone deacetylases (HDACs) are among the most thoroughly studied epigenetic regulators, controlling key physiological and pathological cellular processes by regulating histone acetylation levels and post-translational modifications of non-histone proteins. Currently, 18 human HDAC subtypes (HDAC1-11, SIRT1-7) have been identified, and they are closely related to the development and progression of various diseases (Annu. Rev. Biochem. 2007, 76, 75-100; ActaPharm. Sin. B. 2023, 13, 2425-2463). Among all HDAC subtypes, HDAC6 is the most unique, primarily located in the cytoplasm, and regulates the function of many disease-related proteins through its deacetylation activity (Epigenomics, 2015, 7, 103–118). HDAC6 plays an important role in cell motility and invasiveness formation and is a potential target for the treatment of a variety of diseases. Research on selective HDAC6 inhibitors is of great value (Science, 2020, 369, 1448; Cells, 2021, 10, 12).

[0003] Therefore, developing highly selective inhibitors targeting different HDAC subtypes is of great significance. Currently, six HDAC inhibitors have been approved for marketing, used to treat lymphoma, multiple myeloma, and breast cancer, among others. Known histone deacetylase inhibitors can be structurally classified into four categories: 1. Hydroxamic acid analogs, represented by compounds such as Voronostat (approved in 2006), Belinostat (approved in 2014), Panobinostat (approved in 2015), and Givinostat (approved in 2024); 2. Benzamide analogs, represented by compounds such as Tucidinostat (approved in 2014), Entinosta (Phase III clinical trial), and Mocetinostat (Phase II clinical trial); 3. Cyclic peptides, represented by Romidepsin (approved in 2009); and 4. Aliphatic carboxylic acids, represented by compounds such as Valproic acid (Phase III clinical trial).

[0004] Most of the aforementioned inhibitors are non-selective HDACs inhibitors, which can inhibit multiple signaling pathways, leading to strong toxic side effects. Currently known selective HDAC6 inhibitors mostly use hydroxamic acid as a zinc ion chelating group, such as Rocilinostat (Phase III clinical trials), Tubastatin A, and Nexturastat A. However, these HDAC6 inhibitors not only have poor selectivity for Class I HDACs but also poor pharmacokinetic properties and potential toxicity. These shortcomings limit the clinical application of hydroxamic acid-based selective HDAC6 inhibitors (J.Med.Chem. 2021, 64, 1362-1391). In previous studies, we discovered the first acylhydrazine-based selective HDAC6 inhibitor (J.Med.Chem. 2022, 65, 12140-12162). This compound exhibits excellent pharmacokinetic properties and good subtype selectivity; however, subsequent experiments revealed toxicity at high doses due to inhibition of other HDAC subtypes. Discovering HDAC6 inhibitors with excellent pharmacokinetic properties and subtype selectivity is an urgent problem to be solved in this field. Summary of the Invention

[0005] This application addresses the selectivity limitations of previously disclosed compounds by creatively solving this long-standing problem in our research field through a structural optimization strategy. It provides a more precise and efficient mechanism of action for subsequent drug development, demonstrating broad application prospects and significant innovative value.

[0006] To address the technical problems existing in the prior art, the primary objective of this application is to provide a novel compound for inhibiting HDAC6. This compound uses a fused ring structure as its core skeleton and introduces an acylhydrazine group as a chelating part for zinc ions, thereby constituting a highly efficient selective inhibitor of HDAC6. The compound exhibits excellent anti-inflammatory activity, as well as high HDAC6 inhibitory activity and excellent subtype selectivity, opening up new avenues for research and application in related fields.

[0007] A second objective of this application is to provide a method for preparing the above-described compound, wherein the method involves reasonable steps and the synthesized compound is stable.

[0008] A third objective of this application is to provide applications of the compounds described above.

[0009] To develop potential HDAC6 selective inhibitors, the inventors conducted in-depth research on the structural characteristics of current HDAC6 inhibitors and the uniqueness of the HDAC6 protein, and analyzed the shortcomings of HDAC6 inhibitors. Based on the HDAC6 protein structure, molecular design was carried out, and the previously reported acylhydrazine-based HDAC6 inhibitors were further structurally optimized. Finally, a novel HDAC6 selective inhibitor was synthesized and successfully verified, thus forming this application.

[0010] The specific technical solution of this application is as follows:

[0011] 1. A compound of formula (I) or a pharmaceutically acceptable salt thereof, characterized in that the structure of the compound of formula (I) is as follows:

[0012]

[0013] Wherein, R1 is selected from

[0014] L is selected from a bond, alkylene group, or carbonyl group;

[0015] R2, R3, R4 and R5 are each independently selected from: H, alkyl, halogen, hydroxyl and -OR7;

[0016] R6 is selected from: H, substituted or unsubstituted alkyl, cycloalkyl, -C(O)-R8, -C(O)NH2 and -C(S)NH2.

[0017] 2. The compound according to claim 1 or a pharmaceutically acceptable salt thereof, characterized in that L is an alkylene group, preferably, the alkylene group is C1-C6. 12 Alkylene, more preferably C1-C4 alkylene.

[0018] 3. The compound according to claim 1 or 2 or a pharmaceutically acceptable salt thereof, characterized in that the halogen is fluorine, chlorine, bromine or iodine.

[0019] 4. The compound according to any one of claims 1-3, or a pharmaceutically acceptable salt thereof, characterized in that the alkyl group, R7, and R8 are each independently C1-C6. 12 Alkyl groups, more preferably C1-C4 alkyl groups.

[0020] 5. The compound according to any one of items 1-4 or a pharmaceutically acceptable salt thereof, wherein the substitution is replaced by a halogen, preferably fluorine, chlorine, bromine or iodine.

[0021] 6. The compound according to any one of claims 1-5, or a pharmaceutically acceptable salt thereof, characterized in that the cycloalkyl group is C3-C6. 15The cycloalkyl group, preferably a C3-C6 cycloalkyl group.

[0022] 7. The compound according to any one of items 1-6, or a pharmaceutically acceptable salt thereof, wherein the compound is: 4-((11H-benzo[b]pyridino[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-3-fluorobenzohydrazine, 4-((11H-benzo[b]pyridino[4,3-f]azacycloheptane-11-yl)methyl)-3-chloro-N'-ethylbenzohydrazine, 4-((11H-benzo[b]pyridino[4,3-f]azacycloheptane-11-yl)methyl)-3-bromo-N'-ethylbenzohydrazine, 4-((11H-benzo[b]pyridino[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-3-iodobenzohydrazine 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-3-methoxybenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2-fluorobenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-2-chloro-N'-ethylbenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-2-bromo ...- 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2-methoxybenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-3,5-difluorobenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2,6-difluorobenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2,5-difluorobenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,b ... 4-(11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2,3-difluorobenzohydrazine, 3-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethylbenzohydrazine, 4-(11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)-N'-ethylbenzohydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl) ...3-f]azacycloheptane-11-yl)methyl)-N'-methylbenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-(2-fluoroethyl)benzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-(2,2-difluoroethyl)benzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N' -(2,2,2-trifluoroethyl)benzo[a]hydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-(tert-butyl)benzo[a]hydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-cyclopropylbenzo[a]hydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-iso ... b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-acetylbenzohydrazine, 2-(4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)benzoyl)hydrazine-1-carboxamide, 2-(4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)benzoyl)hydrazine-1-thiocarboxamide, 4-((9H-carbazol-9-yl)methyl)-N'-ethyl-2,5-difluorobenzoyl Hydrazine, 4-((9H-pyrido[2,3-b]indol-9-yl)methyl)-N'-ethyl-2,5-difluorobenzoylhydrazine, 4-((10H-benzo[b]pyrido[2,3-e][1,4]thiazin-10-yl)methyl)-N'-ethyl-2,5-difluorobenzoylhydrazine, 4-((5H-dibenzo[b,f]azacycloheptane-5-yl)methyl)-N'-ethyl-2,5-difluorobenzoylhydrazine or N'-ethyl-2,5-difluoro-4-(quinoline-8-amino)methyl)benzoylhydrazine.

[0023] 8. A method for preparing the compound or a pharmaceutically acceptable salt thereof as described in any one of items 1-7, comprising the following steps:

[0024]

[0025] 9. The method according to item 8, wherein,

[0026] Using a compound containing R1 as a raw material, intermediate 2 is obtained by reacting it with intermediate 1 under the action of sodium hydride; or by reacting it with intermediate 1 under the action of diisopropylaminolithium; or by reacting it with intermediate 2 under the action of Pd2(dba)3; or by reacting it with intermediate 1 under the action of 4-dimethylaminopyridine.

[0027] Intermediate 3 is obtained by hydrolysis of intermediate 2 as a raw material;

[0028] Intermediate 4 is obtained by reacting intermediate 3 with an R6-substituted hydrazine group in the presence of 2-(7-azabenzotriazole)-N,N,N',N'-tetramethylurea hexafluorophosphate to give general formula I.

[0029] 10. A pharmaceutical composition comprising any one of claims 1-7, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable diluent or carrier.

[0030] 11. The compound or a pharmaceutically acceptable salt thereof as described in any one of items 1-7, used as a medicine.

[0031] 12. Use of any compound of any one of items 1-7 or a pharmaceutically acceptable salt thereof in the preparation of an HDAC6 inhibitor or in the preparation of a treatment for diseases associated with abnormal expression of HDAC6 activity.

[0032] 13. According to the use described in item 12, the diseases associated with abnormal HDAC6 activity expression include inflammatory and autoimmune diseases, tumors, neurodegenerative diseases, nervous system diseases, diabetes, and cardiovascular and cerebrovascular diseases.

[0033] 14. The use according to item 13, wherein the inflammatory and autoimmune diseases include inflammatory bowel disease (IBD), psoriasis, sepsis, arthritis, gout, acute lung injury, or systemic lupus erythematosus; and / or

[0034] The tumors include triple-negative breast cancer, lung cancer, melanoma, esophageal cancer, prostate cancer, breast cancer, cervical cancer, ovarian cancer, gastric cancer, pancreatic cancer, bladder cancer, colorectal cancer, brain tumors, gliomas, anaplastic oligodendrogliomas, adult glioblastoma, adult anaplastic astrocytoma, bone cancer, or soft tissue sarcoma; and / or

[0035] The neurodegenerative diseases mentioned include Parkinson's disease (PD), Alzheimer's disease (AD), cerebral ischemia (CI), brain injury (BI), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS), different types of spinocerebellar ataxia (SCA), epilepsy, Huntington's disease, or Pick's disease; and / or

[0036] The cardiovascular and cerebrovascular diseases mentioned include stroke or atherosclerosis.

[0037] The effects of the invention

[0038] The compounds described in this application can be used to inhibit HDAC6 and have strong subtype selectivity for HDAC6. Attached Figure Description

[0039] Figure 1 The study demonstrated the selective inhibition of HDAC6 by compound I-13 in MV4-11 cells.

[0040] Figure 2 The graph shows the relationship between the levels of compound I-13 and IL-1β.

[0041] Figure 3 The activity of compound I-13 in acute peritonitis was demonstrated.

[0042] Figures 4A to 4C Compound I-13 was shown to have activity in inflammatory bowel disease, in which Figure 4A The DAI score is the score of mice treated with different compounds. Figure 4B It is the colon length of mice treated with different compounds. Figure 4C These are pathological sections of mice treated with different compounds.

[0043] Figures 5A to 5C Compound I-13 was shown to have activity in psoriasis, in which Figure 5A This is a schematic diagram showing the treatment status of the skin of mice that received different compounds. Figure 5B This is a diagram showing the body weight of mice treated with different compounds. Figure 5C This is a schematic diagram of H&E sections of mice treated with different compounds. Detailed Implementation

[0044] The present application will now be described in detail with reference to the described embodiments. Although specific embodiments of the present application are shown, it should be understood that the present application can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the scope of the present application to those skilled in the art.

[0045] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions in the specification are preferred embodiments for carrying out this application; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of this application. The scope of protection of this application shall be determined by the appended claims.

[0046] definition

[0047] As used herein, the prefix "Cx-Cy" indicates that the following group has x (e.g., 1) to y (e.g., 12) carbon atoms, and in some groups, one or more of these atoms may be substituted by one or more heteroatomic or heteroatom groups. For example, "(C1-C 12 "alkyl" indicates that the alkyl group has 1 to 12 carbon atoms.

[0048] As used herein, the term "alkyl" refers to any group derived from a straight-chain or branched saturated hydrocarbon, which may be arbitrarily substituted with one, two, or three substituents. Unless otherwise expressly stated, the term "alkyl" is intended to include saturated, unsaturated, and partially unsaturated aliphatic groups. When specifically referring to an unsaturated group, the terms "alkenyl" or "ynyl" are used. When referring only to a saturated group, the term "alkyl" is used. Preferably, alkyl includes, but is not limited to, methyl, ethyl, propyl such as prop-1-yl, prop-2-yl (isopropyl), butyl such as but-1-yl (n-butyl), but-2-yl (sec-butyl), 2-methyl-prop-1-yl (isobutyl), 2-methyl-prop-2-yl (tert-butyl), pentyl, hexyl, octyl, decyl, etc. Unless otherwise stated, alkyl has 1 to 12 carbon atoms, for example 1 to 8 carbon atoms, for example 1 to 6 carbon atoms, for example 1 to 4 carbon atoms, for example 1 to 2 carbon atoms.

[0049] As used herein, the term "alkylene" itself, or as part of another substituent, refers to an alkyl-derived divalent group, such as, but not limited to: -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH2CH=CHCH2-, -CH2C≡CCH2-, -CH2CH2CH(CH2CH2CH3)CH2-. Typically, alkyl (or alkylene) groups have 1-24 carbon atoms, and groups having 12 or fewer carbon atoms are preferred in this application.

[0050] As used herein, the term "cycloalkyl" refers to the cyclic form of an "alkyl" group. Examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.

[0051] As used herein, the term "halogen" refers to a fluorine, chlorine, bromine, or iodine atom. Furthermore, terms such as "halogen-substituted alkyl" indicate both monohalogenated and polyhalogenated alkyl groups. For example, the term "halogen-substituted (C1-C4) alkyl" includes, but is not limited to, monofluoromethyl, difluoromethyl, trifluoromethyl, 2,2,2-trifluoroethyl, 4-chlorobutyl, 3-bromopropyl, etc.

[0052] As used herein, the term "alkoxy" refers to the -O-alkyl portion, wherein the alkyl portion is as defined above. Non-limiting examples include methoxy, ethoxy, propoxy, butoxy, etc. The alkoxy group may be optionally substituted or unsubstituted. For example, (C1-C2)alkoxy refers to an alkyl portion having 1-2 carbon atoms bonded to an oxygen atom.

[0053] As used herein, the term "substituted" refers to one or more hydrogen atoms in a group, preferably up to five, more preferably one to three hydrogen atoms, that are independently substituted by the corresponding number of substituents. It goes without saying that the substituents are only in their possible chemical positions, and that a person skilled in the art can determine (by experiment or theory) the possible or impossible substitutions without much effort. For example, an amino or hydroxyl group with free hydrogen may be unstable when bonded to a carbon atom with an unsaturated bond (such as an alkene).

[0054] As used herein, the term "pharmaceutically acceptable salt" is intended to include salts of active compounds prepared with a relatively non-toxic acid or base based on a specific substituent moiety present on the compound described herein. When the compounds of this application contain relatively acidic functional groups, a base addition salt can be obtained by contacting the compound in a neutral form with a sufficient amount of a desired base in a pure form or in a suitable inert solvent. Examples of pharmaceutically acceptable base addition salts include sodium, potassium, calcium, ammonium, organic amino, or magnesium salts, or similar salts. When the compounds of this application contain relatively basic functional groups, an acid addition salt can be obtained by contacting the compound in a neutral form with a sufficient amount of a desired acid in a pure form or in a suitable inert solvent. Examples of pharmaceutically acceptable acid addition salts include salts derived from inorganic acids such as hydrochlorides, hydrobroms, nitrates, carbonates, bicarbonates, phosphates, monohydrogen phosphates, dihydrogen phosphates, sulfates, bisulfates, hydroiodates, or phosphites, as well as salts formed from relatively non-toxic organic acids such as acetates, propionates, isobutyrates, maleates, malonates, benzoates, succinates, octanoates, fumarate lactates, mandelates, phthalates, benzenesulfonates, p-toluenesulfonates, citrates, tartrates, and methanesulfonates. Also included are salts of amino acids such as arginine salts and salts of organic acids such as glucuronic acid or galacturonic acid (see, for example, Berge et al., "Pharmaceutical Salts," Journal of Pharmaceutical Science, 1977, 66, 1-19). Certain specific compounds of this application may contain both basic and acidic functional groups, enabling the compound to be converted into a basic or acid addition salt.

[0055] In addition to the salt form, this application also provides the prodrug form of the compound. The prodrugs described herein refer to those compounds that readily undergo chemical changes under physiological conditions to provide the compound of this application. Furthermore, the prodrug can be converted into the compound of this application in an in vitro environment by chemical or biochemical methods. For example, when placed in a transdermal patch reservoir with suitable enzymes or chemical reagents, the prodrug can be slowly converted into the compound of this application.

[0056] Those skilled in the art will understand that salts of compounds of formula (I), including pharmaceutically acceptable salts, can be prepared. These salts can be prepared in situ during the final isolation and purification of the compound, or by independently reacting the purified compound, in its free acid or free base form, with a suitable base or acid.

[0057] It can form pharmaceutically acceptable acid addition salts with inorganic and organic acids, such as acetates, aspartates, benzoates, benzenesulfonates, bromides / hydrobromoates, bicarbonates / carbonates, hydrogen sulfates / sulfates, camphor sulfonates, chlorides / hydrochlorides, citrates, ethanedisulfonates, fumarates, gluconate, gluconate, glucuronide, hippurate, hydroiodide / iodide, hydroxyethyl sulfonate, lactates, lactobionates, lauryl sulfate, malates, maleates, malonates, mandelates, methanesulfonates, methyl sulfates, naphthates, naphthalenesulfonates, nicotinates, nitrates, stearates, oleates, oxalates, palmitic acids, dihydroxynaphthalates, phosphates / hydrogen phosphates / dihydrogen phosphates, polygalacturonic acids, propionates, stearates, succinates, sulfosalicylates, tartrates, toluenesulfonates, and trifluoroacetates.

[0058] Inorganic acids that can form salts include, for example, hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, and phosphoric acid.

[0059] Organic acids that can form salts include, for example, acetic acid, propionic acid, glycolic acid, oxalic acid, maleic acid, malonic acid, succinic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, toluenesulfonic acid, and sulfosalicylic acid. Pharmaceutically acceptable base addition salts can form with inorganic or organic bases.

[0060] Inorganic bases that can form salts include, for example, ammonium salts and metals from Groups I to XII of the periodic table. In some embodiments, the salt is derived from sodium, potassium, ammonium, calcium, magnesium, iron, silver, zinc, and copper; particularly suitable salts include ammonium salts, potassium salts, sodium salts, calcium salts, and magnesium salts.

[0061] Organic bases that can form salts include, for example, primary, secondary, and tertiary amines. Substituted amines include naturally occurring substituted amines, cyclic amines, and basic ion exchange resins. Some organic amines include isopropylamine, diethanolamine, diethylamine, lysine, meglumine, piperazine, and aminobutanetriol.

[0062] The pharmaceutically acceptable salts of the present invention can be synthesized from basic or acidic portions using conventional chemical methods. Typically, these salts can be prepared by reacting the free acidic form of these compounds with a suitable stoichiometric amount of a base (hydroxides, carbonates, bicarbonates, etc. of Na, Ca, Mg, or K), or by reacting the free basic form of these compounds with a suitable stoichiometric amount of an acid. These reactions are typically carried out in water, in an organic solvent, or in a mixture of both. Typically, a non-aqueous medium, such as diethyl ether, ethyl acetate, ethanol, isopropanol, or acetonitrile, is required where appropriate. A list of other suitable salts can be found in Remington's Pharmaceutical Sciences, 20th edition, Mack Publishing Company, Easton, Pa., (1985); and Stahl and Wermuth's Handbook of Pharmaceutical Salts: Properties, Selection, and Use (Wiley-VCH, Weinheim, Germany, 2002).

[0063] Solvents of compounds of formula (I) can also be prepared, including pharmaceutically acceptable solvates. A “solvent” is a complex of variable stoichiometry formed by a solute and a solvent. Such solvents for the purposes of this invention do not affect the biological activity of the solute. Examples of suitable solvents include, but are not limited to, water, MeOH, EtOH, and AcOH. A solvate in which water is a solvent molecule generally refers to a hydrate. Hydrates include components containing stoichiometric amounts of water, as well as components containing variable amounts of water.

[0064] Compounds of formula (I), including their salts and solvates, may exist in crystalline, amorphous, or mixtures thereof. The compounds, their salts, or solvates may also exhibit polymorphism, i.e., the ability to appear in different crystalline forms. These different crystalline forms are generally known as "polymorphs." Polymorphs have the same chemical composition but differ in the packing, geometric arrangement, and other descriptive properties of their crystalline solid states. Therefore, polymorphs can have different physical properties, such as shape, density, hardness, deformability, stability, and solubility. Polymorphs typically exhibit different melting points, IR spectra, and X-ray powder diffraction patterns, all of which can be used for identification. Those skilled in the art will understand that, for example, different polymorphs may be produced by changing or adjusting the conditions used in the crystallization / recrystallization of the compounds of formula (I).

[0065] This invention also includes different isomers of the compound of formula (I). An "isomer" is a compound having the same composition and molecular weight but different physical and / or chemical properties. The structural difference can be in the structure (geometric isomers) or in the ability to rotate plane-polarized light (stereoisomers). Regarding stereoisomers, the compound of formula (I) may have one or more asymmetric carbon atoms and may appear as racemic mixtures, racemic mixtures, and as a single enantiomer or diastereomer. All such isomer forms are included within the scope of this invention, including mixtures thereof. If the compound contains a double bond, the substituent may be of E or Z configuration. If the compound contains a disubstituted cycloalkyl group, the substituent of the cycloalkyl group may have a cis- or trans-configuration. It is also desirable to include all tautomer forms.

[0066] Any asymmetric atom (e.g., carbon) in the compound of formula (I) can be present in racemic or enantiomeric enrichment, such as (R)-, (S)-, or (R,S)- configurations. In some embodiments, each asymmetric atom has at least 50% enantiomeric excess, at least 60% enantiomeric excess, at least 70% enantiomeric excess, at least 80% enantiomeric excess, at least 90% enantiomeric excess, at least 95% enantiomeric excess, or at least 99% enantiomeric excess in the (R)- or (S)- configuration. Where possible, substituents on atoms having unsaturated double bonds are present in cis-(Z)- or trans-(E)- form.

[0067] Therefore, as used herein, the compound of formula (I) can be in the form of one of the possible isomers, rotational isomers, tautomers, tautomers or mixtures thereof, for example as a substantially pure geometric isomer (cis or trans), diastereomer, optical isomer (enantiomer), racemic mixture or mixture thereof.

[0068] Any mixture of the resulting isomers can be separated into pure or substantially pure geometric or optical isomers, diastereomers, racemates, for example by chromatography and / or stepwise crystallization, based on the physicochemical differences of the components.

[0069] Any racemic product or intermediate obtained can be resolved into its optically active enantiomers by known methods (e.g., by separation of its diastereomeric salts), obtained with an optically active acid or base, and releasing an optically active acidic or basic compound. In particular, the basic moiety can therefore be used to resolve the compounds of the invention into their optically active enantiomers, for example by stepwise crystallization of salts formed with optically active acids (e.g., tartaric acid, dibenzoyltartaric acid, diacetyltartaric acid, di-O,O'-p-toluyltartaric acid, mandelic acid, malic acid, or camphor-10-sulfonic acid). Racemic products can also be resolved by chiral chromatography, such as high-performance liquid chromatography (HPLC) using chiral adsorbents.

[0070] This invention includes both unlabeled and isotopically labeled forms of compounds of formula (I). The isotopically labeled compounds have the structure described by the chemical formula given herein, except that one or more atoms are replaced by atoms having a selected atomic weight or mass number. Examples of isotopes that can be incorporated into the compounds of this invention include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorus, fluorine, and chlorine, respectively, for example… 2 H, 3 H, 11 C 13 C 14 C 15 N、 18 F, 31 P, 32 P, 35 S, 36 Cl、 125 I. This invention includes various isotope-labeled compounds as defined herein, such as those containing a radioactive isotope (e.g., 3 H

[0071] and 14 C) those or those containing non-radioactive isotopes (e.g. 2 H and 13 Those of C). These isotopically labeled compounds can be used in metabolic studies (e.g., using...) 14 C) Reaction kinetic studies (e.g., using...) 2 H or 3 H) Detection or imaging techniques, such as positron emission tomography (PET) or single-photon emission computed tomography (SPECT), including drug substrate tissue distribution analysis, or for use in patient radiation therapy. In particular, PET or SPECT studies may require specific techniques. 18F or labeled compounds. Isotope-labeled compounds of formula (I) can generally be prepared by conventional techniques known to those skilled in the art or by methods similar to those described in the appended examples and preparation examples, using suitable isotope-labeled reagents instead of previously used unlabeled reagents.

[0072] In addition, heavier isotopes, especially deuterium (i.e., 2 Substitution with H or D may result in certain therapeutic advantages due to greater metabolic stability, such as increased in vivo half-life or reduced dose requirements or improved therapeutic index. It is understood that deuterium is considered a substituent for compounds of formula (I) herein. The concentration of the heavier isotope, particularly deuterium, may be determined by the isotope enrichment factor. As used herein, the term "isotope enrichment factor" refers to the ratio between the isotopic abundance and the native abundance of a particular isotope. If the substituent in the compound of the present invention is labeled as deuterium, then for each labeled deuterium atom, the compound has an isotopic enrichment factor of at least 3500 (52.5% deuterium doping at each labeled deuterium atom), at least 4000 (60% deuterium doping), at least 4500 (67.5% deuterium doping), at least 5000 (75% deuterium doping), at least 5500 (82.5% deuterium doping), at least 6000 (90% deuterium doping), at least 6333.3 (95% deuterium doping), at least 6466.7 (97% deuterium doping), at least 6600 (99% deuterium doping), or at least 6633.3 (99.5% deuterium doping).

[0073] Those skilled in the art will be able to identify the presence of a stereocenter in the compound of formula (I). Therefore, the present invention includes possible stereoisomers, and includes both racemic compounds and single enantiomers. When the desired compound is a single enantiomer, it can be obtained by stereospecific synthesis or by resolution of the end product or any convenient intermediate. Resolution of the end product, intermediate, or starting material can be achieved by any suitable method known in the art. See, for example, “Stereochemistry of Organic Compounds” by E.L. Leel, S.H. Wilen, and L.N. Mander (Wiley-interscience, 1994).

[0074] As used herein, the term "treatment" refers to the successful cure or improvement of an injury, lesion, or disease, including any objective or subjective indicator such as relief; mitigation; reduction of symptoms or increased patient tolerance to the injury, lesion, or disease; slowing of the rate of degeneration or worsening; milder degeneration; or improvement of the patient's physical or mental health. Treatment or symptom relief may be based on objective or subjective parameters, including the results of physical examination, neuropsychiatric examination, and / or psychiatric evaluation. For example, some of the methods described herein have successfully treated cancer by reducing its incidence or alleviating its symptoms.

[0075] As used in this article, the term "effective amount" refers to an amount sufficient to treat, prevent, or alleviate the symptoms of a disease. "Effective amount" may also be called "therapeutic effective amount." "Amelioration" of symptoms (and its grammatical equivalent) indicates a reduction in the severity or frequency of symptoms, or the disappearance of symptoms.

[0076] As used herein, the term "pharmaceutically acceptable" means a compound suitable for pharmaceutical use. Salts and solvates (e.g., hydrates and salt hydrates) of the compounds of this application suitable for pharmaceutical use are those in which the counterion or bound solvent is pharmaceutically acceptable. However, salts and solvates having non-pharmaceutically acceptable counterions or bound solvents are also included within the scope of this application, for example, as intermediates in the preparation of other compounds of this application and their pharmaceutically acceptable salts and solvates.

[0077] Compound of formula (I)

[0078] This application provides compounds of formula (I) or pharmaceutically acceptable salts thereof, characterized in that the structure of the compounds of formula (I) is as follows:

[0079]

[0080] Wherein, R1 is selected from

[0081] L is selected from a bond, alkylene group, or carbonyl group;

[0082] R2, R3, R4 and R5 are each independently selected from: H, alkyl, halogen, hydroxyl and -OR7;

[0083] R6 is selected from: H, substituted or unsubstituted alkyl, cycloalkyl, -C(O)-R8, -C(O)NH2 and -C(S)NH2.

[0084] In some embodiments, the alkylene group is C1-C. 12Alkylene, more preferably C1-C4 alkylene. For example, the alkylene can be -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, etc., and in some embodiments, the alkylene is -CH2-.

[0085] In some embodiments, the halogen is fluorine, chlorine, bromine, or iodine. In some embodiments, the halogen is fluorine. In some embodiments, the halogen is chlorine. In some embodiments, the halogen is bromine. In one embodiment, the halogen is iodine.

[0086] In some embodiments, the alkyl group, R7, and R8 are each independently C1-C. 12 Alkyl groups, more preferably C1-C4 alkyl groups. For example, the alkyl group, R7, and R8 can each independently be CH3-, CH3CH2-, CH3CH2CH2-, CH3CH2CH2CH2-, CH3CH(CH2)CH2-, C(CH3)3-, etc. In some embodiments, the alkyl group, R7, and R8 are each independently CH3-.

[0087] In some embodiments, the substitution can be substituted with a halogen, preferably fluorine, chlorine, bromine, or iodine, most preferably fluorine; preferably, the substitution is from monosubstituted to maximally substituted, where, in this application, maximally substituted means that the hydrogen in the alkyl group is completely substituted. For example, when the alkyl group is CH3-, it can be monosubstituted, disubstituted, trisubstituted, etc., with a halogen such as fluorine. For example, the substituted alkyl group can be CH2F-, CHF2-, CF3-.

[0088] In some embodiments, the cycloalkyl group is C3-C. 15 The cycloalkyl group is preferably a C3-C6 cycloalkyl group. In some embodiments, the cycloalkyl group is cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc.

[0089] In some implementations, R1 is L, R2, R3, R4, R5, and R6 are defined as above.

[0090] In some implementations, R1 is L is the key, and R2, R3, R4, R5, and R6 are defined as above.

[0091] In some implementations, R1 is L represents an alkylene group, which is C1-C6. 12 Alkylenes, R2, R3, R4, R5 and R6 are as defined above.

[0092] In some implementations, R1 is L is an alkylene group, which is a C1-C4 alkylene group, and R2, R3, R4, R5 and R6 are as defined above.

[0093] In some implementations, R1 is L is -CH2-, and R2, R3, R4, R5 and R6 are as defined above.

[0094] In some implementations, R1 is L is a carbonyl group, and R2, R3, R4, R5, and R6 are as defined above.

[0095] In some implementations, R1 is L represents an alkylene group, which is C1-C6. 12 The alkylene groups R2, R3, R4 and R5 are each independently selected from: H, alkyl, halogen, hydroxyl and -OR7, wherein halogen, alkyl, R7 and R6 are as defined above.

[0096] In some implementations, R1 is L represents an alkylene group, which is C1-C6. 12 The alkylene groups R2, R3, R4, and R5 are each independently selected from: H, alkyl, halogen, hydroxyl, and -OR7, where the alkyl group and R7 are C1-C. 12 Alkyl, halogen and R6 are as defined above.

[0097] In some implementations, R1 is L represents an alkylene group, which is C1-C6. 12 The alkylene groups R2, R3, R4 and R5 are each independently selected from: H, alkyl, halogen, hydroxyl and -OR7, where alkyl and R7 are C1-C4 alkyl, and halogen and R6 are as defined above.

[0098] In some implementations, R1 is L represents an alkylene group, which is C1-C6. 12 Alkylenes, R2, R3, R4 and R5 are each independently selected from: H, alkyl, halogen, hydroxyl and -OR7, where alkyl and R7 are CH3, and halogen and R6 are as defined above.

[0099] In some implementations, R1 is L is an alkylene group, which is a C1-C4 alkylene group. R2, R3, R4 and R5 are each independently selected from: H, alkyl, halogen, hydroxyl and -OR7. The alkyl group and R7 are CH3. The halogen and R6 are as defined above.

[0100] In some implementations, R1 is L is -CH2-, and R2, R3, R4 and R5 are each independently selected from: H, CH3, F, Cl, Br, I, OH or OCH3, and R6 is as defined above.

[0101] In some implementations, R1 is L represents an alkylene group, which is C1-C6. 12 Alkylene, R6 is selected from H, substituted or unsubstituted alkyl, cycloalkyl, -C(O)-R8, -C(O)NH2 and -C(S)NH2, and the cycloalkyl is C3-C 15 The cycloalkyl groups, substituted or unsubstituted alkyl groups, R8, R2, R3, R4 and R5 are as defined above.

[0102] In some implementations, R1 is L is an alkylene group, which is a C1-C4 alkylene group. R6 is selected from H, substituted or unsubstituted alkyl groups, cycloalkyl groups, -C(O)-R8, -C(O)NH2 and -C(S)NH2. The cycloalkyl group is a C3-C6 cycloalkyl group, wherein the substituted or unsubstituted alkyl groups, R8, R2, R3, R4 and R5 are as defined above.

[0103] In some implementations, R1 is L is -CH2-, R6 is selected from H, substituted or unsubstituted alkyl, cycloalkyl, -C(O)-R8, -C(O)NH2 and -C(S)NH2, the cycloalkyl is cyclopropyl, wherein the substituted or unsubstituted alkyl, R8, R2, R3, R4 and R5 are as defined above.

[0104] In some implementations, R1 is L is -CH2-, R6 is selected from H, substituted or unsubstituted alkyl, cycloalkyl, -C(O)-R8, -C(O)NH2 and -C(S)NH2, the cycloalkyl is cyclopropyl, and the alkyl and R8 are C1-C. 12 Alkyl groups, wherein the substitutions, R2, R3, R4 and R5 are as defined above.

[0105] In some implementations, R1 is L is -CH2-, R6 is selected from H, substituted or unsubstituted alkyl, cycloalkyl, -C(O)-R8, -C(O)NH2 and -C(S)NH2, the cycloalkyl is cyclopropyl, the alkyl and R8 are C1-C4 alkyl, wherein the substitution, R2, R3, R4 and R5 are as defined above.

[0106] In some implementations, R1 is L is -CH2-, R6 is selected from H, substituted or unsubstituted alkyl, cycloalkyl, -C(O)-R8, -C(O)NH2 and -C(S)NH2, cycloalkyl is cyclopropyl, alkyl and R8 are CH3, wherein the substitution, R2, R3, R4 and R5 are as defined above.

[0107] In some implementations, R1 is L is -CH2-, R6 is selected from H, substituted or unsubstituted alkyl, cycloalkyl, -C(O)-R8, -C(O)NH2 and -C(S)NH2, cycloalkyl is cyclopropyl, alkyl and R8 are CH3, substitution is by halogen, and R2, R3, R4 and R5 are as defined above.

[0108] In some implementations, R1 is L is -CH2-, R6 is selected from H, substituted or unsubstituted alkyl, cycloalkyl, -C(O)-R8, -C(O)NH2 and -C(S)NH2, cycloalkyl is cyclopropyl, alkyl and R8 are CH3, substitution is fluorine substitution, and R2, R3, R4 and R5 are as defined above.

[0109] In some implementations, R1 is L is -CH2-, and R6 is selected from H, CH3, ... R2, R3, R4, and R5 are defined as above.

[0110] In some implementations, L is a key, where R1, R2, R3, R4, R5, and R6 are as defined above.

[0111] In some embodiments, L is an alkylene group, wherein the alkylene group, R1, R2, R3, R4, R5, and R6 are as defined above.

[0112] In some embodiments, L is an alkylene group, wherein the alkylene group is C1-C60. 12 Alkylenes, wherein R1, R2, R3, R4, R5 and R6 are as defined above.

[0113] In some embodiments, L is an alkylene group, which is a C1-C4 alkylene group, wherein R1, R2, R3, R4, R5 and R6 are as defined above.

[0114] In some embodiments, L is an alkylene group, wherein the alkylene group is -CH2-, and R1, R2, R3, R4, R5 and R6 are as defined above.

[0115] In some embodiments, L is a carbonyl group, wherein R1, R2, R3, R4, R5 and R6 are as defined above.

[0116] In some embodiments, L is an alkylene group, wherein the alkylene group is C1-C60. 12 The alkylene groups R2, R3, R4 and R5 are each independently selected from H, alkyl, halogen, hydroxyl and -OR7, wherein alkyl, halogen, R7, R1 and R6 are as defined above.

[0117] In some embodiments, L is an alkylene group, which is a C1-C4 alkylene group, and R2, R3, R4 and R5 are each independently selected from H, alkyl, halogen, hydroxyl and -OR7, wherein alkyl, halogen, R7, R1 and R6 are as defined above.

[0118] In some embodiments, L is -CH2-, and R2, R3, R4 and R5 are each independently selected from H, alkyl, halogen, hydroxyl and -OR7, wherein alkyl, halogen, R7, R1 and R6 are as defined above.

[0119] In some embodiments, L is -CH2-, and R2, R3, R4, and R5 are each independently selected from H, alkyl, halogen, hydroxyl, and -OR7, with the alkyl and R7 each being independently C1-C. 12 Alkyl groups, wherein halogens, R1 and R6 are as defined above.

[0120] In some embodiments, L is -CH2-, and R2, R3, R4 and R5 are each independently selected from H, alkyl, halogen, hydroxyl and -OR7, wherein the alkyl and R7 are each independently C1-C4 alkyl, wherein the halogen, R1 and R6 are as defined above.

[0121] In some embodiments, L is -CH2-, R2, R3, R4 and R5 are each independently selected from H, alkyl, halogen, hydroxyl and -OR7, alkyl and R7 are each independently CH3, wherein halogen, R1 and R6 are as defined above.

[0122] In some embodiments, L is -CH2-, R2, R3, R4 and R5 are each independently selected from H, alkyl, halogen, hydroxyl and -OR7, alkyl and R7 are each independently CH3, halogen is fluorine, chlorine, bromine or iodine, wherein R1 and R6 are as defined above.

[0123] In some implementations, L is -CH2-, and R2, R3, R4 and R5 are each independently selected from H, CH3, F, Cl, Br, I, OH or OCH3, wherein R1 and R6 are as defined above.

[0124] In some embodiments, L is -CH2-, R2, R3, R4, and R5 are each independently selected from H, CH3, F, Cl, Br, I, OH, or OCH3, and R6 is selected from: H, substituted or unsubstituted alkyl groups, cycloalkyl groups, -C(O)-R8, -C(O)NH2, and -C(S)NH2, wherein the alkyl group and R8 are each independently C1-C6. 12 Alkyl groups, wherein substitutions and R1 are as defined above.

[0125] In some embodiments, L is -CH2-, R2, R3, R4 and R5 are each independently selected from H, CH3, F, Cl, Br, I, OH or OCH3, and R6 is selected from: H, substituted or unsubstituted alkyl, cycloalkyl, -C(O)-R8, -C(O)NH2 and -C(S)NH2, wherein the alkyl and R8 are each independently C1-C4 alkyl, wherein the substitution and R1 are as defined above.

[0126] In some embodiments, L is -CH2-, R2, R3, R4 and R5 are each independently selected from H, CH3, F, Cl, Br, I, OH or OCH3, and R6 is selected from H, substituted or unsubstituted alkyl, cycloalkyl, -C(O)-R8, -C(O)NH2 and -C(S)NH2, wherein the alkyl and R8 are each independently CH3alkyl, wherein the substitution and R1 are as defined above.

[0127] In some embodiments, L is -CH2-, R2, R3, R4 and R5 are each independently selected from H, CH3, F, Cl, Br, I, OH or OCH3, and R6 is selected from: H, substituted or unsubstituted alkyl, cycloalkyl, -C(O)-R8, -C(O)NH2 and -C(S)NH2, wherein the alkyl and R8 are each independently CH3alkyl, and the substitution is substituted by a halogen, wherein the halogen and R1 are as defined above.

[0128] In some embodiments, L is -CH2-, R2, R3, R4 and R5 are each independently selected from H, CH3, F, Cl, Br, I, OH or OCH3, R6 is selected from: H, substituted or unsubstituted alkyl, cycloalkyl, -C(O)-R8, -C(O)NH2 and -C(S)NH2, wherein the alkyl and R8 are each independently CH3alkyl, the substitution is substituted by a halogen, wherein the halogen is fluorine, chlorine, bromine or iodine, wherein R1 is as defined above.

[0129] In some embodiments, L is -CH2-, R2, R3, R4 and R5 are each independently selected from H, CH3, F, Cl, Br, I, OH or OCH3, R6 is selected from: H, substituted or unsubstituted alkyl, cycloalkyl, -C(O)-R8, -C(O)NH2 and -C(S)NH2, wherein the alkyl and R8 are each independently CH3alkyl, the substitution is substituted by a halogen, wherein the halogen is fluorine, and R1 is as defined above.

[0130] In some embodiments, L is -CH2-, R2, R3, R4, and R5 are each independently selected from H, CH3, F, Cl, Br, I, OH, or OCH3, and R6 is selected from H, CH3, R1 is defined as above.

[0131] In some embodiments, L is -CH2-, R2, R3, R4, and R5 are each independently selected from H, CH3, F, Cl, Br, I, OH, or OCH3, and R6 is selected from H, CH3, R1 is

[0132] In some embodiments, L is -CH2-, R2, R3, R4, and R5 are each independently selected from H, CH3, F, Cl, Br, I, OH, or OCH3, and R6 is selected from H, CH3, R1 is

[0133] In some embodiments, L is -CH2-, R2, R3, R4, and R5 are each independently selected from H, CH3, F, Cl, Br, I, OH, or OCH3, and R6 is selected from H, CH3, R1 is

[0134] In some embodiments, L is -CH2-, R2, R3, R4, and R5 are each independently selected from H, CH3, F, Cl, Br, I, OH, or OCH3, and R6 is selected from H, CH3, R1 is

[0135] In some embodiments, L is -CH2-, R2, R3, R4, and R5 are each independently selected from H, CH3, F, Cl, Br, I, OH, or OCH3, and R6 is selected from H, CH3, R1 is

[0136] In some embodiments, L is -CH2-, R2, R3, R4, and R5 are each independently selected from H, CH3, F, Cl, Br, I, OH, or OCH3, and R6 is selected from H, CH3, R1 is

[0137] In some embodiments, L is -CH2-, R2, R3, R4, and R5 are each independently selected from H, CH3, F, Cl, Br, I, OH, or OCH3, and R6 is selected from H, CH3, R1 is

[0138] In some embodiments, L is -CH2-, R2, R3, R4, and R5 are each independently selected from H, CH3, F, Cl, Br, I, OH, or OCH3, and R6 is selected from H, CH3, R1 is

[0139] In some embodiments, L is -CH2-, R2, R3, R4, and R5 are each independently selected from H, CH3, F, Cl, Br, I, OH, or OCH3, and R6 is selected from H, CH3, R1 is

[0140] In some embodiments, L is a bond, and the compound of formula (I) or its pharmaceutically acceptable salt has the following structure:

[0141]

[0142] In some implementations, R1 is R2, R3, R4, and R5 are H, and R6 is

[0143] In some embodiments, L is CH2, and the compound of formula (I) or its pharmaceutically acceptable salt has the following structure:

[0144]

[0145] In some implementations, R1 is R2, R3, R4, and R5 are each independently selected from: H, CH3, F, Cl, Br, I, OH, or OCH3; R6 is selected from H, CH3, ...

[0146] In some implementations, R1 is R2 and R5 are F, R3 and R4 are H, and R6 is...

[0147] In some implementations, L is The compounds of formula (I) or their pharmaceutically acceptable salts have the following structures:

[0148]

[0149] In some implementations, R1 is R2, R3, R4, and R5 are H, and R6 is

[0150] In some preferred embodiments of the application, certain groups in the compound shown in I are defined as follows (undefined groups are as described in any embodiment of this application).

[0151]

[0152] In some implementations, R2 is F, R3, R4, and R5 are H, and R6 is...

[0153] In some implementations, R2 and R3 are F, R4 and R5 are H, and R6 is...

[0154] In some implementations, R3 is F, R2, R4, and R5 are H, and R6 is...

[0155] In some implementations, R2 and R4 are F, R3 and R5 are H, and R6 is...

[0156] In some implementations, R3 and R5 are F, R2 and R4 are H, and R6 is...

[0157] In some implementations, R2 is Cl, R3, R4, and R5 are H, and R6 is...

[0158] In some implementations, R2 is Br, R3, R4, and R5 are H, and R6 is...

[0159] In some implementations, R2 is I, R3, R4 and R5 are H, and R6 is

[0160] In some implementations, R2 is OCH3, R3, R4, and R5 are H, and R6 is...

[0161] In some preferred embodiments of the application, certain groups in the compound shown in I are defined as follows (undefined groups are as described in any embodiment of this application).

[0162]

[0163] In some implementations, R2 is F, R3, R4, and R5 are H, and R6 is...

[0164] In some implementations, R2 and R3 are F, R4 and R5 are H, and R6 is...

[0165] In some implementations, R3 is F, R2, R4, and R5 are H, and R6 is...

[0166] In some implementations, R2 and R4 are F, R3 and R5 are H, and R6 is...

[0167] In some implementations, R3 and R5 are F, R2 and R4 are H, and R6 is...

[0168] In some implementations, R2 is Cl, R3, R4, and R5 are H, and R6 is...

[0169] In some implementations, R2 is Br, R3, R4, and R5 are H, and R6 is...

[0170] In some implementations, R2 is I, R3, R4 and R5 are H, and R6 is

[0171] In some implementations, R2 is OCH3, R3, R4, and R5 are H, and R6 is...

[0172] In some embodiments, the compound is: 4-((11H-benzo[b]pyridino[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-3-fluorobenzoylhydrazine, 4-((11H-benzo[b]pyridino[4,3-f]azacycloheptane-11-yl)methyl)-3-chloro-N'-ethylbenzoylhydrazine, 4-((11H-benzo[b]pyridino[4,3-f]azacycloheptane-11-yl)methyl)-3-bromo-N'-ethylbenzoylhydrazine, 4-((11H-benzo[b]pyridino[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-3-iodo ... Heptane-11-yl)methyl)-N'-ethyl-3-methoxybenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2-fluorobenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-2-chloro-N'-ethylbenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-2-bromo-N'-ethylbenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2-iodobenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2-iodobenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2-iodobenzoylhydrazine, 4-((11H-benzo[b]pyridinium) 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2-methoxybenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-3,5-difluorobenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2,6-difluorobenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,bf]azacycloheptane-11-yl)methyl)-N'-ethyl-2,5-difluorobenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2,3-difluorobenzoylhydrazine Benzyl hydrazide, 4-(11H-benzo[b]pyrido[4,3-f]azacyclopenten-11-carbonyl)-N'-ethylbenzoyl hydrazide, 3-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethylbenzoyl hydrazide, 4-(11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)-N'-ethylbenzoyl hydrazide, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)benzoyl hydrazide, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-methylbenzoyl hydrazide, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-methylbenzoyl hydrazide, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-methylbenzoyl hydrazide, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-methylbenzoyl hydrazide, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-methylbenzoyl hydrazide,3-f]azacycloheptane-11-yl)methyl)-N'-(2-fluoroethyl)benzohydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-(2,2-difluoroethyl)benzohydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-(2,2,2-trifluoroethyl)benzohydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-(2,2,2-trifluoroethyl)benzohydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-(2,2,2-trifluoroethyl)benzohydrazine, 4-((11H-benzo[b]pyrido[4 ,3-f]azacycloheptane-11-yl)methyl)-N'-(tert-butyl)benzohydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-cyclopropylbenzohydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-isopropylbenzohydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl) 2-(4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)benzoyl)hydrazine-1-carboxamide, 2-(4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)benzoyl)hydrazine-1-thiocarboxamide, 4-((9H-carbazole-9-yl)methyl)-N'-ethyl-2,5-difluorobenzoylhydrazine, 4-((9H-pyrido) [2,3-b]indol-9-yl)methyl)-N'-ethyl-2,5-difluorobenzoylhydrazine, 4-((10H-benzo[b]pyrido[2,3-e][1,4]thiazin-10-yl)methyl)-N'-ethyl-2,5-difluorobenzoylhydrazine, 4-((5H-dibenzo[b,f]azacycloheptane-5-yl)methyl)-N'-ethyl-2,5-difluorobenzoylhydrazine or N'-ethyl-2,5-difluoro-4-(quinoline-8-amino)methyl)benzoylhydrazine.

[0173] Preparation method

[0174] This application provides a method for preparing the above-described compound or a pharmaceutically acceptable salt thereof, comprising the following steps:

[0175]

[0176] In some embodiments, during reaction 1, the compound containing R1 and intermediate 1 undergo a palladium-catalyzed CN coupling reaction to obtain intermediate 2. The reaction conditions and operations are conventional conditions and operations known to those skilled in the art. For example, the reaction conditions used in this application may be: tris(dibenzylideneacetone)dipalladium (Pd2(dba)3), 2-dicyclohexylphosphino-2'-(N,N-dimethylamine)-biphenyl (Davephos), t-BuONa, DMF, 100°C, 12h.

[0177] In some embodiments, during reaction 1, the compound containing R1 undergoes an amide condensation reaction with intermediate 1 to obtain intermediate 2. The reaction conditions and operations are conventional conditions and operations known to those skilled in the art. For example, the reaction conditions used in this application can be: 4-dimethylaminopyridine, triethylamine, 50°C, 6h.

[0178] In some embodiments, during reaction 1, the compound containing R1 undergoes a substitution reaction with intermediate 1 to obtain intermediate 2. The reaction conditions and operations are conventional conditions and operations known to those skilled in the art. For example, the reaction conditions used in this application may be: lithium diisopropylamino (LDA), KI, 18-crown ether-6, THF, -20°C-rt, 12h.

[0179] In this application, the term "compound containing R1" refers to any compound containing an R1 substituent. This application does not impose any restrictions on the compound containing R1, as long as it can react with intermediate 1 to obtain intermediate 2.

[0180] In some embodiments, during reaction 2, intermediate 2 is hydrolyzed with methyl ester to obtain intermediate 3. The reaction conditions and operations are conventional conditions and operations known to those skilled in the art. For example, the reaction conditions used in this application can be: KOH, MeOH, 45°C, 2h.

[0181] In some embodiments, during reaction 3, intermediate 3 is condensed with hydrazine substituted with R6 to obtain compound (I). The reaction conditions and operations are conventional conditions and operations known to those skilled in the art. The reaction conditions used in this application may be: 2-(7-azabenzotriazole)-N,N,N',N'-tetramethylurea hexafluorophosphate (HATU), N,N-diisopropylethylamine (DIPEA), DMF, rt, 6h.

[0182] Pharmaceutical compositions and therapeutic uses

[0183] The present invention also provides compounds of formula (I) described above or pharmaceutically acceptable salts thereof for use as medicines.

[0184] This application provides a pharmaceutical composition comprising a compound of formula (I) described above or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable diluent or carrier.

[0185] The pharmaceutical compositions described in this application can be formulated for specific routes of administration, such as oral administration, parenteral administration, and rectal administration. Furthermore, the pharmaceutical compositions of this application can be prepared in solid form (non-limitingly including capsules, tablets, pills, granules, powders, or suppositories) or in liquid form (non-limitingly including solutions, suspensions, or emulsions). The pharmaceutical compositions can undergo conventional pharmaceutical processes (e.g., sterilization) and / or can contain conventional inert diluents, lubricants, or buffers, as well as excipients such as preservatives, stabilizers, wetting agents, emulsifiers, and buffers.

[0186] Typically, pharmaceutical compositions are tablets or capsules containing an active ingredient and the following:

[0187] a) Diluents, such as lactose, dextrose, sucrose, mannitol, sorbitol, cellulose, glycine, etc.;

[0188] b) Lubricants, such as silica, talc, stearic acid, its magnesium or calcium salts, and / or polyethylene glycol; may also be included in tablets:

[0189] c) Adhesives, such as magnesium aluminum silicate, starch paste, gelatin, tragacanth gum, methylcellulose, sodium carboxymethyl cellulose and / or polyvinylpyrrolidone; and if necessary.

[0190] d) Disintegrants, such as starch, agar, alginate or its sodium salt, or effervescent mixtures; and / or

[0191] e) Absorbents, colorants, flavorings and sweeteners.

[0192] According to methods known in the art, tablets can be film-coated or enteric-coated.

[0193] Suitable compositions for oral administration include an effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof, in the form of tablets, lozenges, aqueous or oil suspensions, dispersible powders or granules, emulsions, hard or soft capsules, or syrups or elixirs. Compositions for oral use are prepared according to any method known in the art for preparing pharmaceutical compositions, and to provide a refined and palatable formulation, the composition may contain one or more agents selected from sweeteners, flavoring agents, coloring agents, and preservatives. Tablets may contain the active ingredient mixed with a non-toxic, pharmaceutically acceptable excipient suitable for preparing tablets. These excipients are, for example, inert diluents (e.g., calcium carbonate, sodium carbonate, lactose, calcium phosphate, or sodium phosphate); granulating and disintegrants (e.g., corn starch, or alginate); binders (e.g., starch, gelatin, or gum arabic); and lubricants (e.g., magnesium stearate, stearic acid, or talc). Tablets are either uncoated or coated using known techniques to delay disintegration and absorption in the gastrointestinal tract, thereby providing a prolonged effect over a longer period. For example, delaying materials such as glyceryl monostearate or glyceryl distearate can be used. Oral formulations can be presented in hard gelatin capsules, wherein the active ingredient is mixed with an inert solid diluent (e.g., calcium carbonate, calcium phosphate, or kaolin), or in soft gelatin capsules, wherein the active ingredient is mixed with an aqueous or oily medium (e.g., peanut oil, liquid paraffin, or olive oil).

[0194] Some injectable compositions are isotonic aqueous solutions or suspensions, and suppositories are advantageously prepared from fat emulsions or suspensions. The compositions may be sterilized and / or contain excipients such as preservatives, stabilizers, wetting or emulsifiers, dissolution promoters, salts and / or buffers for adjusting osmotic pressure. Furthermore, they may contain other therapeutically valuable substances. The compositions are prepared according to conventional mixing, granulation, or coating methods and contain approximately 0.1-75% or approximately 1-50% of the active ingredient.

[0195] Since water may promote the degradation of certain compounds, this application also provides anhydrous pharmaceutical compositions and dosage forms comprising the compounds of this application as active ingredients.

[0196] The anhydrous pharmaceutical compositions and dosage forms of this application can be prepared using anhydrous or low-water-content ingredients and low-water-content or low-humidity conditions. Anhydrous pharmaceutical compositions can be prepared and stored to maintain their anhydrous properties. Therefore, anhydrous compositions are packaged using materials known to prevent contact with water so that they can be contained in suitable formulation boxes. Examples of suitable packaging, without limitation, include airtight foil, plastics, unit-dose containers (e.g., tubular bottles), blister packs, and strip packs.

[0197] This application further provides pharmaceutical compositions and dosage forms comprising one or more agents that reduce the decomposition rate of the compound of this application as an active ingredient. Such agents (referred herein as "stabilizers") include, but are not limited to, antioxidants (e.g., ascorbic acid), pH buffers, or salt buffers.

[0198] For an individual weighing approximately 50-70 kg, the pharmaceutical composition or combination product of this application can be a unit dose of approximately 1-1000 mg of the active ingredient, or approximately 1-500 mg, or approximately 1-250 mg, or approximately 1-150 mg, or approximately 0.5-100 mg, or approximately 1-50 mg of the active ingredient. The therapeutically effective dose of the compound, pharmaceutical composition, or combination product thereof depends on the individual's species, weight, age, and individual circumstances, the condition or disease being treated, or its severity. A physician, clinician, or veterinarian of general skill can readily determine the effective amount of each active ingredient required for the prevention, treatment, or inhibition of the development of a condition or disease.

[0199] This application also provides the use of compounds of formula (I) as described above or pharmaceutically acceptable salts thereof in the preparation of HDAC6 inhibitors.

[0200] This application also provides the use of compounds of formula (I) as described above, or pharmaceutically acceptable salts thereof, in the preparation of treatments for diseases associated with abnormal expression of HDAC6 activity.

[0201] In some embodiments, the diseases associated with abnormal HDAC6 activity expression include inflammatory and autoimmune diseases, tumors, neurodegenerative diseases, diabetes, and cardiovascular and cerebrovascular diseases.

[0202] In some embodiments, the inflammatory and autoimmune diseases include: inflammatory bowel disease (IBD), psoriasis, sepsis, gout, acute lung injury, arthritis (including rheumatoid arthritis, juvenile rheumatoid arthritis, osteoarthritis, psoriatic arthritis), multiple sclerosis, myasthenia gravis, systemic lupus erythematosus, autoimmune thyroiditis, dermatitis (including atopic dermatitis and eczematous dermatitis), Hughlen syndrome (including dry keratoconjunctivitis secondary to Hughlen syndrome), alopecia areata, allergic reactions caused by arthropod bites, Crohn's disease, gastric ulcer, iritis, conjunctivitis, etc. Keratitis and conjunctivitis, ulcerative colitis, asthma, allergic asthma, cutaneous lupus erythematosus, scleroderma, vaginitis, proctitis, drug response, leprosy, lupus erythematosus, autoimmune uveitis, allergic encephalomyelitis, acute necrotizing hemorrhagic encephalopathy, progressive bilateral idiopathic hearing loss, aplastic anemia, anemia, idiopathic thrombocytopenic purpura, multiple chondritis, Wagner's granulomatosis, chronic active hepatitis, Stephen Johnson syndrome, idiopathic stomatitis, lichen planus, Graves' ophthalmopathy, sarcoidosis, primary biliary cirrhosis, posterior uveitis, interstitial pulmonary fibrosis.

[0203] In some embodiments, the tumor includes: cancer, tumor growth, colon cancer, breast cancer, bone cancer, brain cancer and other cancers (e.g., osteosarcoma, neuroblastoma, colon adenocarcinoma), chronic myeloid leukemia (CML), and acute myeloid leukemia (AML). Leukaemia (AML), acute promyelocytic leukemia (APL), gastric cardia cancer (sarcoma, myxoma, rhabdomyosarcoma, fibroma, lipoma, and teratoma), lung cancer (e.g., bronchial carcinoma, alveolar carcinoma, bronchial adenoma, sarcoma, lymphoma, chondromatous hamartoma, mesothelioma), gastrointestinal cancer (e.g., esophageal cancer, gastric cancer, pancreatic cancer, small bowel cancer, large colorectal cancer), genitourinary tract cancer (e.g., kidney cancer, bladder cancer, urethral cancer, prostate cancer, testicular cancer), liver cancer (e.g., hepatocellular carcinoma, bile duct cancer, hepatoblastoma, angiosarcoma, hepatocellular adenoma, hemangioma), bone cancer (e.g., osteosarcoma, fibrosarcoma, malignant fibrous histiocytoma, chondrosarcoma). Ewing's sarcoma, malignant lymphoma, multiple myeloma, malignant giant cell tumor, chordoma, chondroma, benign chordoma, chondroblastoma, chondromyxofibroma, osteoid osteoma), nervous system tumors (e.g., skull tumor, meningioma, brain tumor, spinal cord tumor), gynecological tumors (e.g., uterine tumor, cervical tumor, ovarian tumor, vulvar and vaginal tumor), hematologic cancers (e.g., hematoma, Hodgkin's disease, non-Hodgkin's disease), skin cancers (e.g., malignant melanoma, basal cell carcinoma, malignant squamous cell carcinoma, Kaposi's sarcoma, dysplastic nevus, lipoma, hemangioma, dermatofibroma, keloid, psoriasis), and adrenal tumors (e.g., neuroblastoma).

[0204] In some embodiments, the neurodegenerative diseases include: Wilson's disease, spinocerebellar ataxia, prion disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis (ALS), amyloidosis, Alzheimer's disease, Alexander's disease, alcoholic liver disease, cystic fibrosis, Pick's disease, spinal muscular atrophy, and Lewy body dementia.

[0205] In some implementations, cardiovascular and cerebrovascular diseases include stroke and atherosclerosis.

[0206] The diseases associated with abnormal HDAC6 activity further include one or more of the following: rheumatoid spondylitis, post-ischemic reperfusion injury, enteritis, chronic inflammatory lung disease, eczema, asthma, acute respiratory distress syndrome, septic arthritis, chronic progressive arthritis, osteoarthritis, post-traumatic arthropathy, gouty arthritis, Reiter syndrome, acute synovitis, acute spondylitis, glomerulonephritis, hemolytic anemia, aplastic anemia, neutropenia, graft-versus-host disease (GVHD), transplant rejection, chronic thyroiditis, Graves' disease, biliary cirrhosis, contact dermatitis, sunburn, chronic renal failure, and Guillain-Barré syndrome. Syndrome), uveitis, otitis media, periodontitis, pulmonary interstitial fibrosis, bronchitis, sinusitis, pneumoconiosis, pulmonary failure syndrome, emphysema, pulmonary fibrosis, silicosis, or chronic inflammatory diseases of the lungs.

[0207] In some embodiments, a method for treating or preventing diseases associated with abnormal expression of HDAC6 activity is provided, comprising administering to a subject in need a therapeutically effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof.

[0208] In some embodiments, the method includes administering a compound of formula (I) or a pharmaceutically acceptable salt thereof in combination with one, two, three or four other therapeutic agents.

[0209] In this document, if the term "combination" is used to describe combined application, it should be understood that this can mean simultaneous application, independent application, or sequential application. In one aspect of the invention, "combination application" means simultaneous application. In another aspect of the invention, "combination application" means independent application. In yet another aspect of the invention, "combination application" means sequential application. When applied sequentially or independently, the delay in applying the second component should not, for example, negate the benefits of using the combined effect.

[0210] The names and structures of the embodiments are shown in the table below:

[0211]

[0212]

[0213]

[0214]

[0215]

[0216] Example

[0217] This application provides a general and / or specific description of the materials and test methods used in the experiments. In the following examples, unless otherwise specified, % represents wt%, i.e., weight percentage. Reagents or instruments used, unless otherwise specified, are all commercially available conventional reagent products.

[0218] Example 1 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-3-fluorobenzoylhydrazine (compound I-01)

[0219]

[0220] (1) Synthesis of methyl 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-3-fluorobenzoate

[0221] Compound 11H-benzo[b]pyrido[4,3-f]azacycloheptanane (400 mg, 2 mmol), along with catalytic amounts of potassium iodide and octadecyl crown ether hexadecane, were dissolved in anhydrous THF and protected with N2. A 1.5 M solution of lithium diisopropylamino(LDA) in THF (4 mL) was added dropwise at -20 °C, and the reaction was allowed to proceed at 0 °C for 1.5 h after the addition was complete. Then, methyl 4-(bromomethyl)-3-fluorobenzoate (735 mg, 3 mmol) was added, and the reaction proceeded overnight at room temperature. TLC analysis confirmed complete reaction of the starting material. The reaction was quenched with 30 mL of ice water, followed by extraction with ethyl acetate (30 mL × 3). The combined organic phases were dried over anhydrous Na2SO4 for 30 min. The Na2SO4 was removed by filtration, and the filtrate was concentrated under reduced pressure. The mixture was separated by Flash silica gel column chromatography to obtain methyl 4-((11H-benzo[b]pyridino[4,3-f]azacycloheptane-11-yl)methyl)-3-fluorobenzoate (324 mg, yield 45%), as a yellow solid.

[0222] 1 H NMR(400MHz,Chloroform-d)δ8.30(s,1H),8.17(d,J=3Hz,1H),7.67-7.60(m,2H),7.55(t,J=7.2Hz,1H),7.30-7.21(m,1H) ,7.09(d,J=9.4Hz,2H),7.00(t,J=7.4Hz,1H),6.96-6.91(m,2H),6.68(d,J=11.5Hz,1H),5.07(s,2H),3.85(s,3H).UPLC-MS m / z:calcd for C 22 H18 FN2O2[M+H] + :361.1,found:361.0.

[0223] (2) Synthesis of 4-((11H-benzo[b]pyridino[4,3-f]azacycloheptane-11-yl)methyl)-3-fluorobenzoic acid

[0224] Methyl 4-((11H-benzo[b]pyridino[4,3-f]azacycloheptane-11-yl)methyl)-3-fluorobenzoate (540 mg, 1.5 mmol) was dissolved in methanol (25 mL), followed by the addition of 10 mL of 3N KOH aqueous solution and reflux for 2 hours. TLC analysis showed complete reaction of the starting material. After removing methanol under reduced pressure, the pH was adjusted to 5-6 with 1M HCl solution, resulting in the precipitation of a large amount of solid. The solid obtained by filtration, washing the filter cake with water, and drying was 4-((11H-benzo[b]pyridino[4,3-f]azacycloheptane-11-yl)methyl)-3-fluorobenzoic acid (441 mg, yield 85%), a pale yellow solid. UPLC-MS m / z:calcd for C 21 H 15 FN2O2[M+H] + :346.1,found:347.0.

[0225] (3) Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptan-11-yl)methyl)-N'-ethyl-3-fluorobenzohydrazine

[0226] Compound 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-3-fluorobenzoic acid (346 mg, 1 mmol) was dissolved in anhydrous DMF (10 mL). HATU (570 mg, 1.5 mmol) and N,N-diisopropylethylamine (DIPEA, 193 mg, 1.5 mmol) were added under ice bath conditions, and the reaction was allowed to proceed for 30 minutes. Ethylhydrazine (72 mg, 1.2 mmol) was added, and the reaction was allowed to proceed overnight at room temperature. TLC analysis confirmed complete reaction of the starting material. Ethyl acetate (30 mL) was added to the reaction mixture, and the solution was washed with saturated NaHCO3 aqueous solution (3 × 30 mL) and saturated NaCl aqueous solution (2 × 30 mL). The organic phase was dried over anhydrous Na2SO4 for 30 minutes. Na2SO4 was removed by filtration, and the filtrate was concentrated under reduced pressure. The mixture was separated by Flash silica gel column chromatography to obtain compound 4-((11H-benzo[b]pyridino[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-3-fluorobenzohydrazine (221 mg, yield 57%), as a pale yellow solid.

[0227] mp:164-165℃.1 H NMR (400MHz, DMSO-d6) δ9.99 (s, 1H), 8.36 (s, 1H), 8.10 (d, J = 5.0Hz, 1H), 7.54-7.40 (m, 3H), 7.33-7.17 (m, 2H), 7.17 -7.03(m,2H),7.03-6.94(m,2H),6.75(d,J=11.3Hz,1H),5.09(s,2H),2.72(q,J=7.2Hz,2H),0.95(t,J=7.2Hz,3H). 13 CNMR(100MHz,DMSO-d6)δ164.3,162.0,159.6,150.7,146.1,145.1,142.8,141.0,137.1,134.6,133 .0,130.6,130.4,130.2,128.4,124.5,123.4,123.1,121.4,114.5,47.4,45.9,13.5.HRMS(ESI)for C 23 H 22 N4OF[M+H] + calcd 389.1772,found 386.1768.HPLC(λ 254 Purity 96.13%, t R 8.296 min.

[0228] Example 2 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-3-chloro-N'-ethylbenzohydrazine (compound I-02)

[0229]

[0230] In Example 1, methyl 4-(bromomethyl)-3-fluorobenzoate was replaced with methyl 4-(bromomethyl)-3-chlorobenzoate, otherwise the process remained the same as in Example 1. Overall yield was 27%.

[0231] mp:219-220℃. 1H NMR (400MHz, DMSO-d6) δ9.98(s,1H),8.35(s,1H),8.11(d,J=4.7Hz,1H),7.76(s,1H),7.57(s,2H),7.28(t,J=7.7Hz,1H),7.21(d,J=8.2Hz,1H),7. 13(d,J=7.6Hz,1H),7.07(d,J=4.8Hz,1H),6.99(t,J=8.2Hz,2H),6.75(d, J=11.4Hz,1H),5.12(s,2H),2.73(q,J=7.2Hz,2H),0.96(t,J=7.2Hz,3H). 13 C NMR (125MHz, DMSO-d6) δ164.0,150.6,146.0,145.0,142.9,140.9,138.4,137.0,134.1,133.6,133. 0,130.6,130.4,130.3,130.1,128.4,125.9,124.5,123.1,121.5,51.4,45.8,13.5.HRMS(ESI)forC 23 H 22 N4OCl[M+H] + calcd 405.1476,found 405.1475.HPLC(λ 254 Purity 100%,t R 8.994 min.

[0232] Example 3 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-3-bromo-N'-ethylbenzohydrazine (compound I-03)

[0233]

[0234] In Example 1, methyl 4-(bromomethyl)-3-fluorobenzoate was replaced with methyl 4-(bromomethyl)-3-bromobenzoate, otherwise the process remained the same as in Example 1. Overall yield: 25%.

[0235] mp:233-235℃. 1H NMR(400MHz,DMSO-d6)δ9.97(s,1H),8.34(s,1H),8.10(d,J=4.8Hz,1H),7.92(d,J =1.5Hz,1H),7.62-7.54(m,2H),7.32-7.25(m,1H),7.21(d,J=8.1Hz,1H),7.13(d, J=7.7Hz,1H),7.07(d,J=4.9Hz,1H),7.03-6.95(m,2H),6.75(d,J=11.5Hz,1H),5. 09(s,2H),5.01(s,1H),2.72(q,J=7.2Hz,2H),0.95(t,J=7.2Hz,3H).HRMS(ESI)for C 23 H 22 N4OBr[M+H] + calcd 449.0971,found 449.0966.HPLC(λ 254 Purity 100%,t R 9.289 min.

[0236] Example 4 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptan-11-yl)methyl)-N'-ethyl-3-iodobenzoylhydrazine (compound I-04)

[0237]

[0238] In Example 1, methyl 4-(bromomethyl)-3-fluorobenzoate was replaced with methyl 4-(bromomethyl)-3-iodobenzoate, otherwise the process remained the same as in Example 1. Overall yield was 31%.

[0239] mp:219-220℃. 1 H NMR (400MHz, DMSO-d6) δ9.97 (s, 1H), 8.34 (s, 1H), 8.16 (s, 1H), 8.10 (d, J = 4.8Hz, 1H),7.61(d,J=8.2Hz,1H),7.53(d,J=8.1Hz,1H),7.29(t,J=7.7Hz,1H),7.20(d,J =8.2Hz,1H),7.13(d,J=7.6Hz,1H),7.07(d,J=4.9Hz,1H),6.99(t,J=10.0Hz,2H), 6.74(d,J=11.5Hz,1H),5.01(s,2H),2.72(q,J=7.2Hz,2H),0.96(t,J=7.2Hz,3H). 13C NMR (125MHz, DMSO-d6) δ163.8,150.6,145.9,145.0,142.9,142.7,141.0,138.3,137.1,134.1,133 .0,130.4,130.3,130.2,130.1,126.9,124.5,123.1,121.7,100.3,49.0,45.8,13.4.HRMS(ESI)for C 23 H 22 N4OI[M+H] + calcd 497.0832,found497.0829.

[0240] Example 5 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-3-methoxybenzohydrazine (compound I-05)

[0241]

[0242] In Example 1, methyl 4-(bromomethyl)-3-fluorobenzoate was replaced with methyl 4-(bromomethyl)-3-methoxybenzoate, otherwise the process remained the same as in Example 1. Overall yield: 28%.

[0243] mp: 102-103℃. 1 H NMR(400MHz, DMSO-d6)δ9.98(s,1H),8.25(s,1H),8.08(d,J=4.9Hz,1H),7.37(d,J=9.6Hz,2H),7.29-7.18(m,2H),7.17-7.09(m,2H), 7.08-7.03(m,1H),7.02-6.93(m,2H),6.75(d,J=11.4Hz,1H),4.99(s,2H),3.87(s,3H),2.76(q,J=7.2Hz,2H),0.98(t,J=7.2Hz,3H). 13 C NMR (125MHz, DMSO-d6) δ165.4,157.4,151.2,146.4,144.6,142.5,141.1,137.2,133.4,132.9,130.4, 130.3,130.2,129.1,128.7,124.2,123.0,121.3,119.5,109.9,56.2,47.9,45.9,13.4.HRMS(ESI)for C 24 H 25 N4O2[M+H] +calcd401.1972,found 401.1968.HPLC(λ 254 Purity 98.47%, t R 8.420 min.

[0244] Example 6 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2-fluorobenzoylhydrazine (compound I-06)

[0245]

[0246] In Example 1, methyl 4-(bromomethyl)-3-fluorobenzoate was replaced with methyl 4-(bromomethyl)-2-fluorobenzoate, otherwise the process remained the same as in Example 1. Overall yield was 35%.

[0247] mp: 94-95℃. 1 H NMR (400MHz, DMSO-d6) δ9.66 (s, 1H), 8.32 (s, 1H), 8.10 (d, J = 4.8Hz, 1H), 7.40 (t, J = 7.6Hz, 1H), 7.35-7.21 (m, 3H), 7. 20-7.11(m,2H),7.10-6.94(m,3H),6.80(d,J=11.4Hz,1H),5.07(s,2H),2.73(q,J=7.2Hz,2H),0.96(t,J=7.2Hz,3H). 13 C NMR (125MHz, DMSO-d6) δ162.9,160.5,158.5,150.9,146.0,144.9,143.6,143.5,142.6,140.8,137.1,132.9,130.4, 130.3,130.2,130.1,124.4,124.2,124.1,123.0,122.2,122.0,121.3,115.6,115.4,53.2,45.7,13.4.HRMS(ESI)for C 23 H 22 N4OF[M+H] + calcd389.1772,found 389.1769.HPLC(λ 254 Purity 100%,t R 8.250 min.

[0248] Example 7 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-2-chloro-N'-ethylbenzohydrazine (compound I-07)

[0249]

[0250] In Example 1, methyl 4-(bromomethyl)-3-fluorobenzoate was replaced with methyl 4-(bromomethyl)-2-chlorobenzoate, otherwise the process remained the same as in Example 1. Overall yield was 32%.

[0251] mp: 108-110℃. 1 H NMR(400MHz, DMSO-d6)δ9.76(s,1H),8.33(s,1H),8.10(d,J=4.8Hz,1H),7.50(s,1H),7.39(d,J=7.9Hz,1H),7.30-7.23(m,2H),7.19-7 .13(m,2H),7.08(d,J=4.9Hz,1H),7.05-6.97(m,2H),6.80(d,J=11.4Hz,1H),5.06(s,2H),2.73(q,J=7.2Hz,2H),0.96(t,J=7.2Hz,3H). 13 C NMR(125MHz,DMSO-d6)δ165.2,150.8,146.0,144.9,142.6,141.6,140.9,137.1,134.5,132.8,130 .7,130.3,130.2,130.1,129.5,129.2,126.8,124.4,123.0,121.3,53.1,45.7,13.4.HRMS(ESI)for C 23 H 22 N4OCl[M+H] + calcd405.1476,found 405.1473.HPLC(λ 254 Purity 100%,t R 8.293 min.

[0252] Example 8 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-2-bromo-N'-ethylbenzohydrazine (compound I-08)

[0253]

[0254] In Example 1, methyl 4-(bromomethyl)-3-fluorobenzoate was replaced with methyl 4-(bromomethyl)-2-bromobenzoate, otherwise the process remained the same as in Example 1. Overall yield: 31%.

[0255] mp:100-101℃. 1H NMR (400MHz, DMSO-d6) δ9.72(s,1H),8.33(s,1H),8.10(d,J=4.7Hz,1H),7.68(s,1H),7.43(d,J=7.9Hz,1H),7.28(t,J=7.8Hz ,1H),7.24-7.12(m,3H),7.10-6.96(m,3H),6.79(d,J=11.4Hz,1H),5.06(s,2H),2.74(q,J=7.2Hz,2H),0.97(t,J=7.2Hz,3H). 13 C NMR(125MHz,DMSO-d6)δ166.1,150.9,146.0,144.9,142.7,141.7,140.8,137.1,136.7,132.9, 132.3,130.3,130.2,129.4,127.2,124.4,123.0,121.3,119.8,53.0,45.7,13.5.HRMS(ESI)for C 23 H 22 N4OBr[M+H] + calcd 449.0971,found 449.0967.HPLC(λ 254 Purity 100%,t R 8.406 min.

[0256] Example 9 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptan-11-yl)methyl)-N'-ethyl-2-iodobenzoylhydrazine (compound I-09)

[0257]

[0258] In Example 1, methyl 4-(bromomethyl)-3-fluorobenzoate was replaced with methyl 4-(bromomethyl)-2-iodobenzoate, otherwise the process remained the same as in Example 1. Overall yield was 32%.

[0259] mp: 78-79℃. 1H NMR (400MHz, DMSO-d6) δ9.73(s,1H),8.32(s,1H),8.10(d,J=4.8Hz,1H),7.93(s,1H),7.43(d,J=7.9Hz,1H),7.28(t,J=7.5Hz,1H), 7.20-7.11(m,3H),7.10-6.96(m,3H),6.79(d,J=11.4Hz,1H),5.04(d,J=13.0Hz,2H),2.76(q,J=7.0Hz,2H),0.99(t,J=7.0Hz,3H). 13 C NMR (125MHz, DMSO-d6) δ167.8,150.9,146.0,144.8,142.6,141.3,140.9,140.4,138.9,137.1,132 .9,130.3,130.2,130.1,128.6,127.7,124.4,123.0,121.3,94.5,52.8,45.7,13.5.HRMS(ESI)for C 23 H 20 N4OI[MH] - calcd 495.0676, found 495.0679.

[0260] Example 10 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2-methoxybenzohydrazine (compound I-10)

[0261]

[0262] In Example 1, methyl 4-(bromomethyl)-3-fluorobenzoate was replaced with methyl 4-(bromomethyl)-2-methoxybenzoate, otherwise the process remained the same as in Example 1. Overall yield was 33%.

[0263] 1 H NMR (400MHz, DMSO-d6) δ9.40(s,1H),8.31(s,1H),8.09(d,J=4.8Hz,1H),7.49(d,J=7.9Hz,1H),7.26(t,J=7.3Hz,1H),7.22-7 .11(m,4H),7.10-6.94(m,5H),6.80(d,J=11.4Hz,1H),5.06(s,2H),3.73(s,3H),2.75(q,J=7.2Hz,2H),0.96(t,J=7.2Hz,3H). 13CNMR(125MHz,DMSO-d6)δ164.4,157.2,151.2,146.2,144.8,142.9,142.7,141.0,137.2,133.0,130.5 ,130.3,130.2,130.1,124.3,123.0,121.4,121.3,120.3,111.5,56.0,53.8,45.8,13.1.HRMS(ESI)for C 24 H 25 N4O2[M+H] + calcd 401.1972,found 401.1968.HPLC(λ 254 Purity 95.37%, t R 8.495 min.

[0264] Example 11 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-3,5-difluorobenzoylhydrazine (compound I-11)

[0265]

[0266] In Example 1, methyl 4-(bromomethyl)-3-fluorobenzoate was replaced with methyl 4-(bromomethyl)-3,5-difluorobenzoate, otherwise the process remained the same as in Example 1. Overall yield was 27%.

[0267] mp: 203-204℃. 1 H NMR (400MHz, DMSO-d6) δ10.04(s,1H),8.39(s,1H),8.12(d,J=4.8Hz,1H),7.36(d,J=8.4Hz,2H),7.32-7.23(m,2H),7.09(d,J=7.6H z,1H),7.05-6.96(m,2H),6.85(d,J=11.4Hz,1H),6.63(d,J=11.4Hz,1H),5.01(s,2H),2.73(q,J=7.2Hz,2H),0.96(t,J=7.8Hz,3H). 13 C NMR(125MHz,DMSO-d6)δ162.9,160.5,160.4,150.4,145.7,145.3,143.7,141.2,136.6,135.5,133 .3,130.4,130.3,129.7,124.7,123.0,122.3,117.0,110.7,110.5,45.7,43.7,13.5.HRMS(ESI)for C23 H 21 N4OF2[M+H] + calcd 407.1678, found 407.1676.

[0268] Example 12 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2,6-difluorobenzoylhydrazine (compound I-12)

[0269]

[0270] In Example 1, methyl 4-(bromomethyl)-3-fluorobenzoate was replaced with methyl 4-(bromomethyl)-2,6-difluorobenzoate, otherwise the process remained the same as in Example 1. Overall yield: 29%.

[0271] mp: 110-112℃. 1 H NMR (400MHz, DMSO-d6) δ9.91(s,1H),8.33(s,1H),8.12(d,J=5.0Hz,1H),7.29(t,J=7.7Hz,1H),7.19-7.12( m,4H),7.11-6.97(m,4H),6.81(d,J=11.4Hz,1H),5.08(s,2H),2.72(q,J=7.2Hz,2H),0.95(t,J=7.2Hz,3H). 13 C NMR (125MHz, DMSO-d6) δ160.3,158.5,158.3,150.6,145.9,145.1,143.6,142.6,140.8,137.1,132 .9,130.4,130.3,130.2,124.5,123.0,121.2,113.2,111.4,111.2,53.0,45.5,13.3.HRMS(ESI)for C 23 H 21 N4OF2[M+H] + calcd 407.1678,found 407.1676.HPLC(λ 254 Purity 95.02%, t R 8.288 min.

[0272] Example 13 Synthesis of 4-((11H-benzo[b]pyrido[4,bf]azacycloheptane-11-yl)methyl)-N'-ethyl-2,5-difluorobenzoylhydrazine (compound I-13)

[0273]

[0274] In Example 1, methyl 4-(bromomethyl)-3-fluorobenzoate was replaced with methyl 4-(bromomethyl)-2,5-difluorobenzoate, otherwise the process remained the same as in Example 1. Overall yield: 34%.

[0275] mp: 91-92℃. 1 H NMR (400MHz, DMSO-d6) δ9.74(s,1H),8.38(s,1H),8.13(d,J=4.8Hz,1H),7.33-7.19(m,4H),7.15(d,J=7.7Hz,1H),7.09 (d,J=4.8Hz,1H),7.05-6.98(m,2H),6.79(d,J=11.3Hz,1H),5.11(s,2H),2.72(q,J=7.2Hz,2H),0.95(t,J=7.2Hz,3H). 13 C NMR(125MHz,DMSO-d6)δ161.6,157.5,155.5,150.4,145.9,145.2,142.8,140.8,137.0,133.0, 130.4,130.1,124.6,123.0,121.3,117.5,117.3,116.7,116.6,47.2,45.6,13.4.HRMS(ESI)for C 23 H 21 N4OF2[M+H] + calcd 407.1678,found 407.1676.HPLC(λ 254 Purity 97.39%, t R 8.811 min.

[0276] Example 14 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2,3-difluorobenzoylhydrazine (compound I-14)

[0277]

[0278] In Example 1, methyl 4-(bromomethyl)-3-fluorobenzoate was replaced with methyl 4-(bromomethyl)-2,3-difluorobenzoate, otherwise the process remained the same as in Example 1. Overall yield was 28%.

[0279] mp:193-194℃. 1H NMR(400MHz, DMSO-d6)δ9.79(s,1H),8.38(s,1H),8.12(d,J=4.9Hz,1H),7.33-7.19(m,3H),7.19-7.10(m,2H),7.07( d,J=4.8Hz,1H),7.04-6.94(m,2H),6.76(d,J=11.4Hz,1H),5.14(s,2H),2.73(q,J=7.2Hz,2H),0.96(t,J=7.2Hz,3H). 13 C NMR(125MHz,DMSO-d6)δ161.8,150.5,145.9,145.1,142.8,140.8,136.9,133.0,130.3,130 .2,130.1,129.7,129.6,125.1,124.5,124.3,123.0,121.3,47.4,45.6,13.4.HRMS(ESI)for C 23 H 21 N4OF2[M+H] + calcd 407.1678,found 407.1675.HPLC(λ 254 Purity 96.55%, t R 8.639 min.

[0280] Example 15 Synthesis of 4-(11H-benzo[b]pyrido[4,3-f]azacyclopenten-11-carbonyl)-N'-ethylbenzohydrazine (compound I-15)

[0281]

[0282] In step a of Example 1, methyl 4-(bromomethyl)-3-fluorobenzoate and LDA were replaced with methyl 4-(chlorocarbonyl)benzoate and 4-dimethylaminopyridine (DMAP), respectively, otherwise the same as in Example 1. Overall yield: 45%.

[0283] mp: 204-205℃. 1 H NMR(400MHz,DMSO-d6)δ9.99(s,1H),8.57-8.24(m,1H),7.77-7.58(m,3H),7.56-7.44(m,2H),7 .43-7.32(m,2H),7.29-7.07(m,5H),5.04(s,1H),2.74(q,J=7.2Hz,2H),0.97(t,J=7.2Hz,3H). 13C NMR(125MHz,DMSO-d6)δ168.9,164.7,137.8,134.5,130.3,129.2,128.4,128.0,127.1,45.8,13.5.HRMS(ESI) for C 23 H 21 N4O2[M+H] + calcd 385.1659,found 385.1655.HPLC(λ 254 Purity 100%,t R 5.546 min.

[0284] Example 16 Synthesis of 3-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethylbenzohydrazine (compound I-16)

[0285]

[0286] In Example 1, methyl 4-(bromomethyl)-3-fluorobenzoate was replaced with methyl 3-(bromomethyl)benzoate, otherwise the process remained the same as in Example 1. Overall yield was 37%.

[0287] mp: 105-106℃. 1 H NMR (400MHz, DMSO-d6) δ9.99(s,1H),8.32(s,1H),8.07(d,J=4.9Hz,1H),7.89(s,1H),7.53(d,J=7.6Hz,2H),7.29-7.22(m,2H),7.18(d,J=8.1Hz,1H ),7.12(d,J=7.6Hz,1H),7.06(d,J=4.9Hz,1H),7.02-6.94(m,2H),6.76(d ,J=11.4Hz,1H),5.05(s,2H),2.76(q,J=7.2Hz,2H),0.99(t,J=7.2Hz,3H). 13 C NMR(100MHz,DMSO-d6)δ165.8,151.2,146.2,144.7,142.8,141.1,138.5,137.3,133.7,133.0, 131.1,130.3,130.2,128.7,127.8,126.0,124.3,123.1,121.5,53.9,46.0,13.5.HRMS(ESI)for C 23 H 23 N4O[M+H] +calcd 371.1866,found 371.1865.HPLC(λ 254 Purity 59.48%, t R 7.909 min.

[0288] Example 17 Synthesis of 4-(11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)-N'-ethylbenzohydrazine (compound I-17)

[0289]

[0290] In step a of Example 1, methyl 4-(bromomethyl)-3-fluorobenzoate and LDA were replaced with methyl 4-bromobenzoate, Pd2(dba)3, Davephos, and t-BuONa, with the rest remaining the same as in Example 1. Overall yield: 27%.

[0291] mp: 222-223℃. 1 H NMR (400MHz, DMSO-d6) δ9.62(s,1H),8.70(s,1H),8.58(d,J=5.0Hz,1H),7.66-7.53(m,4H),7.48(d,J=8.1Hz,3H),7.14(d ,J=11.4Hz,1H),6.92(d,J=11.4Hz,1H),6.10(d,J=8.4Hz,2H),4.89(s,1H),2.70(q,J=7.2Hz,2H),0.94(t,J=7.2Hz,3H). 13 C NMR (125MHz, DMSO-d6) δ165.5,151.5,150.8,148.7,143.1,142.7,138.2,135.6,135.2,1 31.8,131.5,130.5,128.6,128.5,128.4,124.4,123.8,111.2,46.0,13.5.HRMS(ESI)for C 22 H 21 N4O[M+H] + calcd 357.1710,found 357.1707.HPLC(λ 254 Purity 100%, t R 7.243 min.

[0292] Example 18 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-methylbenzoylhydrazine (compound I-18)

[0293]

[0294] In Example 1, ethylhydrazine was replaced with hydrazine, and the rest was the same as in Example 1. The overall yield was 21%.

[0295] mp: 111-112℃. 1 H NMR (400MHz, DMSO-d6) δ9.62(s,1H),8.30(s,1H),8.06(d,J=4.4Hz,1H),7.62(d,J=8.5Hz,2H),7.45(d,J=7.9Hz,2 H),7.25(t,J=7.6Hz,1H),7.20-7.10(m,2H),7.09-6.92(m,3H),6.77(d,J=10.8Hz,1H),5.06(s,2H),4.63(s,1H). 13 C NMR (125MHz, DMSO-d6) δ166.1,151.1,146.1,144.7,142.7,141.3,140.8,137.1,132. 9,132.4,130.3,130.2,130.1,128.2,127.4,124.2,122.9,121.4,53.7.HRMS(ESI)for C 21 H 19 N4O[M+H] + calcd 343.1553,found 343.1550.HPLC(λ 254 Purity 100%,t R 6.371 min.

[0296] Example 19

[0297] Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-methylbenzoylhydrazine (compound I-19)

[0298]

[0299] In Example 1, ethylhydrazine was replaced with methylhydrazine, and the rest was the same as in Example 1. The overall yield was 24%.

[0300] mp: 91-92℃. 1H NMR(400MHz, DMSO-d6)δ8.33(s,1H),8.10(d,J=3.8Hz,1H),7.74-7.58(m,2H),7.54-7.43(m,2H),7.25(t,J =7.8Hz,1H),7.20-7.08(m,3H),7.07-6.93(m,2H),6.79(d,J=11.4Hz,1H),5.08(s,2H),2.66-2.53(m,3H). 13 C NMR(125MHz,DMSO-d6)δ165.4,151.0,150.9,146.3,144.2,142.0,141.6,137.5,132.8,131.5,1 30.3,130.2,130.1,128.3,128.2,127.8,127.7,124.3,123.2,121.4,53.7,38.1.HRMS(ESI)forC 23 H 21 N4O[M+H] + calcd 357.1710,found 357.1706.HPLC(λ 254 Purity 97.15%, t R 7.028 min.

[0301] Example 20 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-(2-fluoroethyl)benzohydrazine (compound I-20)

[0302]

[0303] In Example 1, ethylhydrazine was replaced with 2-fluoroethylhydrazine, and the rest was the same as in Example 1. The overall yield was 25%.

[0304] mp: 94-95℃. 1 H NMR (400MHz, DMSO-d6) δ9.94 (s, 1H), 8.30 (s, 1H), 8.07 (d, J=

[0305] 4.9Hz,1H),7.69-7.59(m,2H),7.46(d,J=8.1Hz,2H),7.25(t,J=7.7Hz,1H),7.20-7.09(m,2H),7.08-6.92(m,3H),6.77(d,J=11 .4Hz,1H),5.25(s,1H),5.06(s,2H),4.51(t,J=4.9Hz,1H),4.39(t,J=4.9Hz,1H),3.03(t,J=4.9Hz,1H),2.96(t,J=4.9Hz,1H). 13 C NMR(125MHz,DMSO-d6)δ165.8,151.1,144.8,142.7,141.6,140.8,137.1,132.9,132.2, 130.3,130.2,130.1,128.2,127.5,124.2,122.9,121.4,83.0,53.7,51.5.HRMS(ESI)for C 23 H 22 N4OF[M+H] + calcd 389.1772,found 389.1768.HPLC(λ 254 Purity 96.53%, t R 7.712 min.

[0306] Example 21 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-(2,2-difluoroethyl)benzohydrazine (compound I-21)

[0307]

[0308] In Example 1, ethylhydrazine was replaced with 2,2-difluoroethylhydrazine, and the rest was the same as in Example 1. The overall yield was 26%.

[0309] mp: 96-97℃. 1H NMR (400MHz, DMSO-d6) δ9.94(d,J=4.8Hz,1H),8.30(s,1H),8.07(d,J=4.8Hz,1H),7.64(d,J=7.9Hz,2H),7.47(d,J=7.9Hz,2H),7.25(t,J= 7.9Hz,1H),7.20-7.09(m,2H),7.08-6.93(m,3H),6.77(d,J=11.5Hz,1H),6.18-5.84(m,1H),5.43(s,1H),5.06(s,2H),3.17-3.01(m,2H). 13 C NMR (125MHz, DMSO-d6) δ166.3,151.1,146.1,144.7,142.7,141.7,140.8,137.1,132.9,132. 1,130.2,130.1,129.7,128.2,127.6,124.2,122.9,121.4,116.4,53.7,53.5.HRMS(ESI)for C 23 H 21 N4OF2[M+H] + calcd 407.1678,found407.1676.HPLC(λ 254 Purity 96.24%, t R 8.672 min.

[0310] Example 22 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-(2,2,2-trifluoroethyl)benzohydrazine (compound I-22)

[0311]

[0312] In Example 1, ethylhydrazine was replaced with 2,2,2-trifluoroethylhydrazine, otherwise the process remained the same as in Example 1. Overall yield was 22%.

[0313] mp: 85-86℃. 1H NMR (400MHz, DMSO-d6) δ10.03(d,J=4.8Hz,1H),8.30(s,1H),8.07(d,J=4.9Hz,1H),7.65(d,J=7.9Hz,2H),7.47(d,J=7.9Hz ,2H),7.25(t,J=7.7Hz,1H),7.21–7.09(m,2H),7.09–6.93(m,3H),6.77(d,J=11.5Hz,1H),5.06(s,2H),3.55–3.36(m,2H). 13 C NMR(125MHz,DMSO-d6)δ166.63,151.10,146.13,144.79,142.76,141.87,140.79,137.10,13 2.89,131.99,130.25,130.21,128.24,127.70,124.23,122.95,121.37,53.72.HRMS(ESI)for C 23 H 20 N4OF3[M+H] + calcd 425.15834,found 425.1580.HPLC(λ 254 Purity 97.51%, t R 9.357 min.

[0314] Example I-23 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptan-11-yl)methyl)-N'-(tert-butyl)benzohydrazine (compound I-23)

[0315]

[0316] In Example 1, ethylhydrazine was replaced with tert-butylhydrazine, otherwise the process remained the same as in Example 1. Overall yield: 23%.

[0317] mp: 85-86℃. 1 H NMR (400MHz, DMSO-d6) δ9.66(s,1H),8.31(s,1H),8.11-8.04(m,1H),7.65(d,J=7.9Hz,2H),7.48(d,J=7.9Hz,2H),7.25(t,J=7.8Hz, 1H),7.18(d,J=8.1Hz,1H),7.13(d,J=7.6Hz,1H),7.08-6.93(m,3H),6.78(d,J=11.4Hz,1H),5.07(s,2H),4.84(s,1H),0.99(s,9H).13 C NMR (125MHz, DMSO-d6) δ166.0,151.1,146.2,144.8,142.7,141.4,140.8,137.1,132.9,132 .4,130.3,130.2,130.1,128.1,127.7,124.2,122.9,121.4,55.0,53.7,27.7.HRMS(ESI)for C 25 H 27 N4O[M+H] + calcd 399.2179,found399.2177.HPLC(λ 254 Purity 97.51%, t R 9.357 min.

[0318] Example 24 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-cyclopropylbenzohydrazine (compound I-24)

[0319]

[0320] In Example 1, ethylhydrazine was replaced with cyclopropylhydrazine, otherwise the process remained the same as in Example 1. Overall yield was 26%. HRMS(ESI) for C 24 H 23 N4O[M+H] + calcd 383.1866,found 383.1862.

[0321] Example 25 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-isopropylbenzohydrazine (compound I-25)

[0322]

[0323] In Example 1, ethylhydrazine was replaced with isopropylhydrazine, and the rest was the same as in Example 1. The overall yield was 28%.

[0324] mp:155-156℃. 1H NMR (400MHz, DMSO-d6) δ9.84(s,1H),8.31(s,1H),8.07(d,J=4.8Hz,1H),7.65(d,J=7.9Hz,2H),7.47(d,J=7.9Hz,2H),7.25(t,J= 7.8Hz,1H),7.21-7.09(m,2H),7.08-6.92(m,3H),6.78(d,J=11.4Hz,1H),5.06(s,2H),3.06-2.88(m,1H),0.95(d,J=6.2Hz,6H). 13 C NMR(125MHz,DMSO-d6)δ165.8,151.1,146.1,144.7,142.7,141.5,140.8,137.1,132.9,132 .4,130.3,130.2,130.1,128.2,127.6,124.2,123.0,121.4,53.7,50.9,21.3.HRMS(ESI)for C 24 H 23 N4O[MH] - calcd 383.1866,found383.1870.HPLC(λ 254 Purity 100%,t R 8.489 min.

[0325] Example 26 Synthesis of 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-acetylbenzohydrazine (compound I-26)

[0326]

[0327] In Example 1, ethylhydrazine was replaced with acetylhydrazine, and the rest was the same as in Example 1.

[0328] Overall yield: 34%. mp: 92-94℃. 1 H NMR (400MHz, DMSO-d6) δ10.11(s,1H),9.79(s,1H),8.32(s,1H),8.08(d,J=4.9Hz,1H),7.68(d,J=7.8Hz,2H),7.50(d,J=8 .0Hz,2H),7.25(t,J=7.8Hz,1H),7.19-7.10(m,2H),7.09-6.93(m,3H),6.78(d,J=11.4Hz,1H),5.08(s,2H),1.86(s,3H). 13C NMR (125MHz, DMSO-d6) δ168.9,165.7,151.0,146.2,144.6,142.6,142.0,141.1,137.3,132. 9,131.7,130.3,130.2,130.1,128.3,127.9,124.3,123.0,121.4,53.8,21.0.HRMS(ESI)for C 23 H 21 N4O2[M+H] + calcd 385.1659,found 385.1657.HPLC(λ 254 Purity 100%,t R 6.043 min.

[0329] Example 27 Synthesis of 2-(4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)benzoyl)hydrazine-1-carboxamide (compound I-27)

[0330]

[0331] In Example 1, ethylhydrazine was replaced with aminourea, and the rest was the same as in Example 1. The overall yield was 24%.

[0332] mp: 169-171℃. 1 H NMR (400MHz, DMSO-d6) δ9.97(s,1H),8.31(s,1H),8.07(d,J=4.8Hz,1H),7.81(s,1H),7.71(d,J=7.9Hz,2H),7.48(d,J=7 .9Hz,2H),7.25(t,J=7.7Hz,1H),7.20-7.09(m,2H),7.09-6.92(m,3H),6.78(d,J=11.5Hz,1H),5.96(s,2H),5.07(s,2H). 13 C NMR (125MHz, DMSO-d6) δ166.5,151.1,146.1,144.7,142.7,141.9,140.9,137.2,13 2.9,132.0,130.2,130.1,128.1,128.0,124.2,123.0,121.4,53.7.HRMS(ESI)forC 22 H 18 N5O2[MH] - calcd 384.1455,found 384.1459.HPLC(λ 254Purity 100%,t R 5.602 min.

[0333] Example 28 Synthesis of 2-(4-((11H-benzo[b]pyridino[4,3-f]azacycloheptan-11-yl)methyl)benzoyl)hydrazine-1-thiocarboxamide (compound I-28)

[0334]

[0335] In Example 1, ethylhydrazine was replaced with aminothiourea, and the rest was the same as in Example 1. The overall yield was 28%.

[0336] mp:168-169℃. 1 H NMR (400MHz, DMSO-d6) δ9.68(s,1H),8.31(s,1H),8.07(d,J=4.9Hz,1H),7.65(d,J=7.8Hz,2H),7.48(d,J=8 .0Hz,2H),7.25(t,J=7.7Hz,1H),7.21-7.11(m,2H),7.07-6.92(m,3H),6.78(d,J=11.4Hz,1H),5.07(s,2H). 13 C NMR (125MHz, DMSO-d6) δ166.0,151.1,146.2,144.7,142.7,141.5,140.8,137.1,132.9,132. 4,130.3,130.2,130.1,128.2,127.7,124.2,123.0,121.4,55.1,53.7,27.7.HRMS(ESI)forC 22 H 20 N5OS[M+H] + calcd 402.1314,found 402.1312.HPLC(λ 254 Purity 95.64%, t R 9.355 min.

[0337] Example 29 Synthesis of 4-((9H-carbazole-9-yl)methyl)-N'-ethyl-2,5-difluorobenzoylhydrazine (compound I-29)

[0338]

[0339] In Example 1, 11H-benzo[b]pyrido[4,3-f]azacycloheptane and methyl 4-(bromomethyl)-3-fluorobenzoate were replaced with carbazole and methyl 4-(bromomethyl)-2,5-difluorobenzoate, respectively, otherwise the same as in Example 1. Overall yield: 35%.

[0340] mp:146-147℃. 1 H NMR(400MHz, DMSO-d6)δ9.73(s,1H),8.16(d,J=7.8Hz,2H),7.61(d,J=8.1Hz,2H),7.50-7.32(m,3H),7.21( t,J=7.5Hz,2H),6.76-6.58(m,1H),5.73(s,2H),5.22(s,1H),2.73(q,J=7.2Hz,2H),0.94(t,J=7.2Hz,3H). 13 C NMR(125MHz,DMSO-d6)δ161.6,156.3,154.3,140.3,129.3,126.4,122.8,120.9,119.8,117.2,116.6,110.0,45.6,13.4.HRMS(ESI) for C 22 H 20 N3OF2[M+H] + calcd 380.1569,found 380.1568.HPLC(λ 254 Purity 98.23%, t R 11.832 min.

[0341] Example 30 Synthesis of 4-((9H-pyrido[2,3-b]indol-9-yl)methyl)-N'-ethyl-2,5-difluorobenzoylhydrazine (compound I-30)

[0342]

[0343] In Example 1, 11H-benzo[b]pyrido[4,3-f]azacycloheptane and methyl 4-(bromomethyl)-3-fluorobenzoate were replaced with 9H-pyrido[2,3-b]indole and methyl 4-(bromomethyl)-2,5-difluorobenzoate, otherwise the same as in Example 1. Overall yield: 32%.

[0344] mp:151-152℃. 1H NMR (400MHz, DMSO-d6) δ9.72(s,1H),8.56(d,J=7.6Hz,1H),8.46(d,J=4.8Hz,1H),8.22(d,J=7.8Hz,1H),7.60(d,J=8.2Hz,1H),7.49(t,J=7 .8Hz,1H),7.43-7.35(m,1H),7.31-7.23(m,2H),6.85-6.69(m,1H),5.75(s,2H),5.07(s,1H),2.73(q,J=7.2Hz,2H),0.94(t,J=7.2Hz,3H). 13 C NMR(125MHz,DMSO-d6)δ161.6,156.9,155.0,151.2,146.7,139.3,129.4,127.5,122.0,1 20.8,120.5,117.1,116.9,116.8,116.6,116.3,115.8,110.3,45.6,13.4.HRMS(ESI)for C 21 H 19 N4OF2[M+H] + calcd 381.1448,found 381.1447.HPLC(λ 254 Purity 100%,t R 5.315 min.

[0345] Example 31 Synthesis of 4-((10H-benzo[b]pyrido[2,3-e][1,4]thiazin-10-yl)methyl)-N'-ethyl-2,5-difluorobenzoylhydrazine (compound I-31)

[0346]

[0347] In Example 1, 11H-benzo[b]pyrido[4,3-f]azacycloheptane and methyl 4-(bromomethyl)-3-fluorobenzoate were replaced with 10H-benzo[b]pyrido[2,3-e][1,4]thiazine and methyl 4-(bromomethyl)-2,5-difluorobenzoate, otherwise the same as in Example 1. Overall yield: 36%.

[0348] mp:125-126℃. 1H NMR(400MHz, DMSO-d6)δ9.77(s,1H),7.91(dd,J=4.9,1.7Hz,1H),7.46(dd,J=7.5,1.7Hz,1H),7.42-7.35(m,1H),7 .15-7.02(m,2H),6.94-6.84(m,3H),6.79-6.70(m,1H),5.29(s,2H),2.75(q,J=7.2Hz,2H),0.97(t,J=7.2Hz,3H). 13 C NMR (125MHz, DMSO-d6) δ161.7,157.1,155.2,153.6,145.6,141.9,135.2,129.8,128.4,127. 3,124.0,123.1,120.5,119.3,117.0,116.5,116.4,116.1,45.7,43.0,13.4.HRMS(ESI)forC 21 H 19 N4OF2S[M+H] + calcd 413.1242,found 413.1240.HPLC(λ 254 Purity 97.19%, t R 12.246 min.

[0349] Example 32 Synthesis of 4-((5H-dibenzo[b,f]azacycloheptane-5-yl)methyl)-N'-ethyl-2,5-difluorobenzoylhydrazine (compound I-32)

[0350]

[0351] In Example 1, 11H-benzo[b]pyrido[4,3-f]azacycloheptane and methyl 4-(bromomethyl)-3-fluorobenzoate were replaced with 5H-dibenzo[b,f]azapyridine and methyl 4-(bromomethyl)-2,5-difluorobenzoate, otherwise the same as in Example 1. Overall yield: 36%.

[0352] mp: 97-98℃. 1 H NMR (400MHz, DMSO-d6) δ9.73 (s, 1H), 7.33-7.14 (m, 6H), 7.11 (d, J = 7.6Hz, 2H), 7.01-6.93 ( m,2H),6.84(s,2H),5.28(s,1H),5.02(s,2H),2.73(q,J=7.2Hz,2H),0.95(t,J=7.2Hz,3H). 13C NMR(125MHz,DMSO-d6)δ161.7,157.4,155.4,150.3,133.8,132.5,130.3,129.5, 129.5,124.2,123.2,120.9,120.8,117.3,116.6,47.2,45.6,13.4.HRMS(ESI)for C 24 H 22 N3OF2[M+H] + calcd 406.1725, found 406.1722.

[0353] Example 33 Synthesis of N'-ethyl-2,5-difluoro-4-(quinoline-8-amino)methyl)benzohydrazine (compound I-33)

[0354]

[0355] In Example 1, 11H-benzo[b]pyrido[4,3-f]azacycloheptane and methyl 4-(bromomethyl)-3-fluorobenzoate were replaced with 8-aminoquinoline and methyl 4-(bromomethyl)-2,5-difluorobenzoate, otherwise the same as in Example 1. Overall yield: 25%.

[0356] mp:149-150℃. 1 H NMR(400MHz, DMSO-d6)δ9.73(s,1H),8.75(d,J=2.1Hz,1H),8.20(d,J=8.3Hz,1H),7.57-7.45(m,1H),7.37(dd,J=9.7,5.5Hz,1H),7.32-7 .15(m,3H),7.07(d,J=8.2Hz,1H),6.53(d,J=7.7Hz,1H),5.08(s,1H),4.59(d,J=6.7Hz,2H),2.75(q,J=7.2Hz,2H),0.96(t,J=7.2Hz,3H). 13 C NMR(125MHz,DMSO-d6)δ161.8,156.5,155.3,147.7,144.1,138.0,136.5,131.9,1 31.8,128.8,128.1,122.3,116.7,116.5,114.6,105.1,45.7,13.4.HRMS(ESI)for C 19 H 19 N4OF2[M+H] + calcd 357.1521,found 357.1519.

[0357] Example 1: Determination of the in vitro inhibitory activity of HDAC1, HDAC2, HDAC3, and HDAC6

[0358] 50 μL of HDAC buffer containing the drug (where the HDAC buffer is a tris-solution containing 1 mg / mL BSA) was mixed with 10 μL of HDAC1, HDAC2, HDAC3 and HDAC6 enzyme solutions and incubated for 5 min. After adding 40 μL of substrate (Boc-Lys(Ac)-AMC), the reaction was carried out at 37 °C for 30 min. Then, 100 μL of trypsin termination solution was added to terminate the above reaction, and the reaction was carried out at 37 °C for 20 min. The fluorescence intensity was measured at 390 nm / 460 nm.

[0359] Finally, the inhibition rate (%) of the compound and its corresponding concentration were fitted with an S-curve to calculate the IC50. 50 The results are shown in Table 1. Experimental results indicate that, compared with the broad-spectrum HDAC inhibitor SAHA, the compounds described in this application exhibit significantly enhanced activity and selectivity against HDAC6 and its subtypes. Furthermore, compared with the industry-recognized selective HDAC6 inhibitors ACY1215 and 35m (J.Med.Chem.2022,65,12140-12162), these compounds also demonstrate superior subtype selectivity, proving that the compounds described in this application not only possess significant inhibitory activity but also exhibit a clear advantage in subtype selectivity. Among them, compounds I-01, I-13, and I-19 show subtype selectivity for HDAC6 exceeding 100-fold.

[0360] Table 1

[0361]

[0362] Experiment Example 2: Selectivity of HDAC6 cells

[0363] MV4-11 cells (purchased from ATCC) were seeded in 6-well cell culture plates (1×10⁻⁶ cells / well). 6Cells were collected in wells. After 12 hours, cells were treated with compound I-13 at concentration gradients (0.1 μM, 0.3 μM, 1 μM, 3 μM, 9 μM) for 24 hours. After 24 hours, cells were collected, washed twice with PBS, and total protein was extracted with cold RIPA lysis buffer (50 mM Tris base, 150 mM NaCl, 5 mM EDTA, 0.1% (v / v) SDS, 0.5% (v / v) sodium deoxycholate, and 1% (v / v) Triton-X-100). The suspension (total protein) was centrifuged at 12,000 rpm for 15 minutes at 4 °C to obtain the supernatant, and the protein concentration at different compound doses was determined using bis-cinchonas acid (BCA) protein assay. 80 μL of the supernatant was mixed with 20 mL of β-mercaptoethanol and NuPAGE lithium dodecyl sulfate (LDS) sample buffer (5X) to obtain the mixture. The mixture was heated at 100 °C for 10 minutes to obtain the loaded sample. Equal volumes of proteins were separated by 12% SDS-polyacrylamide gel electrophoresis at 120 V and transferred to a polyvinylidene fluoride membrane at 250 mA at 4 °C. After blocking for 2 hours at room temperature with a solution containing 0.05% Tween-20 (TBST) and 5% skim milk, the membrane was incubated overnight at 4 °C with primary antibodies (Ac-HH3 antibody, sc-518011, Santa Cruz Biotechnology; Ac-HH4 antibody, sc-377520, Santa Cruz Biotechnology; Ac-α-tubulin antibody, sc-23950, Santa Cruz Biotechnology) in TBS buffer containing 0.05% Tween-20 (TBST). Subsequently, it was incubated for 1 hour with secondary antibodies that bind to horseradish (HRP) (anti-rabbit IgG, A0208, Beyotime; anti-mouse IgG, A0216, Beyotime) at a dilution of 1:5000. After washing away the secondary antibody with TBST, the protein was detected using an enhanced chemiluminescent reagent (P90719, Millipore).

[0364] Experimental results are as follows Figure 1 As shown, in MV4-11 cells, compared with the positive compound 35m (J.Med.Chem.2022,65,12140-12162), compound I-13 did not induce upregulation of the acetylation levels of class I HDACs-specific substrates HH3 and HH4 at 9000 nM, demonstrating its high subtype selectivity. Therefore, compound I-13 is a potential selective inhibitor of HDAC6.

[0365] Experiment Example 3: Anti-inflammatory Activity Test

[0366] Experimental methods:

[0367] J774A.1 cells (purchased from ATCC) were seeded into 96-well plates (1×10⁻⁶ cells per well). 5 Cells were cultured in wells (cells / well) for 24 hours. Cells were induced for 4.5 hours with *E. coli* O111:B4 LPS (Sigma-Aldrich) (final concentration: 1 μg / mL). Next, the test compound I-13 (0.04, 0.12, 0.37, 1.1, 3.3, 10.0, and 30.0 μM) was added over 30 minutes. ATP (adenine triphosphate, 5 mM) was added concurrently with the test compound to induce NLRP3 inflammasome activation. After 30 minutes, the supernatant was collected, and IL-1β levels were measured using a mouse IL-1β ELISA kit (DuoSet ELISA, R&D Systems) according to the manufacturer's instructions.

[0368] Experimental results: such as Figure 2 As shown, in J774A.1 cells, compound I-13 significantly reduced LPS / ATP-induced IL-1β levels in a concentration-dependent manner, with an IC50 value of [missing information]. 50 The concentration was 1.31 μM, and the activity was superior to the positive control of 35 μM (IC50). 50 =4.45μM), this result is consistent with the enzyme level test results above.

[0369] Experiment 4: Activity test for acute peritonitis in mice

[0370] Experimental Methods: Male C57BL / 6 wild-type mice were randomly divided into four groups (n=6 per group): wild-type mice + solvent control group (solvent: 5% dimethyl sulfoxide + 40% polyethylene glycol 400 + 55% phosphate buffer, dose: 10 mL / kg, intraperitoneal injection); wild-type mice + lipopolysaccharide (LPS, dissolved in phosphate buffer, dose: 10 mg / kg) + solvent (solvent: same as above, dose: 10 mL / kg, intraperitoneal injection); wild-type mice + LPS + test compound group (test compound doses: 20 mg / kg and 40 mg / kg, intraperitoneal injection). Solvent and test compound were administered immediately after intraperitoneal injection of LPS. Blood samples were collected 12 hours after LPS administration in all experiments. Blood samples were centrifuged at 3500 rpm for 10 minutes at 4°C, serum was separated and stored at -80°C for subsequent analysis. According to the manufacturer's instructions, IL-1β levels were measured using the Mouse IL-1β / IL-1F2 DuoSet Enzyme-Linked Immunosorbent Assay Kit (DY401; R&D Systems). The experimental results are as follows: Figure 3 As shown.

[0371] Experimental results: such as Figure 3As shown, compound I-13 significantly reduced IL-1β levels at doses of 20 mg / kg and 40 mg / kg. Multiple studies have shown that insufficient selectivity of compounds for HDAC6 subtypes can induce inflammation at high doses by inhibiting other HDACs (Biochim. Biophys. Acta(BBA)-Gene Regul. Mech. 2018, 1861, 962-970; Nat. Commun. 2018, 9, 3798; Nature 2015, 525, 389-393; Nat. Commun. 2018, 9, 4515). Therefore, it can be concluded that compound I-13 exhibits superior HDAC6 subtype selectivity and possesses significant in vivo anti-inflammatory activity through selective inhibition of HDAC6.

[0372] Experiment 5: Activity test against inflammatory bowel disease in mice

[0373] Experimental Methods: Six female BALB / c mice aged 6 to 8 weeks were used. The normal control group drank normal water for 8 days, the model group drank water containing 4% DSS for 8 days, and the experimental and positive control groups drank water containing 4% DSS for 8 days. From day 1 to day 8, all four groups of mice were intraperitoneally injected with equal volumes of the DSS solution. Simultaneously, the experimental group mice were orally administered the test compound (concentrations of 20 mg / kg and 40 mg / kg, respectively), while the positive control group was orally administered mesalazine (concentration of 100 mg / kg). The DSS solution in the water bottles was changed every two days. During this period, the mice's body weight and fecal blood content were monitored daily. On day 8, DAI scores were calculated, and colonic samples were subjected to biochemical analysis. DAI Scores: During the DSS and drug administration period, mice were examined daily in the morning, and their body weight, water intake, diarrhea score, and bleeding score were recorded. A standardized system was used to determine the DAI (Disease Activity Index) score, including: (a) Diarrhea score: 0 points for normal stool, 2 points for loose stool, and 4 points for watery diarrhea; (b) Hematochezia score: 0 points for no bleeding, 2 points for minor bleeding, and 4 points for significant bleeding; (c) Weight loss score: 0 points for no weight loss, 1%–5% for a weight loss of 1 point, 6%–10% for a weight loss of 2 points, 11%–15% for a weight loss of 3 points, and more than 20% for a weight loss of 4 points. Histological analysis: Transverse colon sections were fixed with 4% formalin buffer and then embedded in paraffin. Hematoxylin and eosin (H&E, purchased from Beijing Solarbio Science & Technology Co., Ltd.) were stained according to standard procedures. The degree of inflammatory cell infiltration was scored as follows: 1 point indicates a localized increase in the number of inflammatory cells in the lamina propria; 2 points indicates inflammatory cells have merged and extended into the submucosa; and 3 points indicates inflammatory cell infiltration has penetrated the entire intestinal wall. The severity of tissue damage was scored as follows: 1 point for discrete lymphoepithelial lesions, 2 points for mucosal erosion, and 3 points for extensive mucosal damage and / or involvement of deeper intestinal wall structures. Two equally weighted sub-scores (inflammatory cell infiltration and tissue damage) were added together to obtain a comprehensive histological colitis severity score ranging from 0 to 6 points.

[0374] Experimental results: such as Figures 4A-4C As shown, where Figure 4A The DAI score is the score of mice treated with different compounds. Figure 4B It is the colon length of mice treated with different compounds. Figure 4C These are pathological sections of mice treated with different compounds.

[0375] from Figures 4A to 4C It can be seen that although DSS-induced colitis leads to colonic shortening and edema, compound I-13 can significantly alleviate these pathological changes. Specifically, compared with the DSS group, mice treated with I-13 achieved significantly lower DAI scores, and these scores were also lower than those of the positive control group. Figure 4AFurthermore, the colon length of mice treated with I-13 was significantly increased. Figure 4B Furthermore, pathological sections of the colon tissue showed that mice in the DSS-treated group developed some degree of colonic ulceration, and I-13 effectively alleviated the corresponding symptoms. Figure 4C Therefore, it can be concluded that I-13 can significantly alleviate colonic inflammation in mice by selectively inhibiting HDAC6.

[0376] Experiment 6: Activity test for psoriasis in mice

[0377] Experimental Methods: Male Balb / c mice (n=8 per group) were orally administered the test compound I-13 (40 mg / kg) and the positive control apremilast (100 mg / kg) for seven consecutive days. Imiquimod (IMQ) cream or petroleum jelly was applied topically to the dorsal skin of the mice. The model control group received only imiquimod (IMQ) cream or petroleum jelly topically on the dorsal skin without any other treatment. The normal control group received no treatment. The erythema, scaling, and thickness of the dorsal skin of the mice were assessed daily using a Psoriasis Area and Severity Index (PASI) scale ranging from 0 to 4.

[0378] Experimental results: such as Figures 5A to 5C As shown, where Figure 5A This is a schematic diagram showing the treatment status of the skin of mice that received different compounds. Figure 5B This is a diagram showing the body weight of mice treated with different compounds. Figure 5C This is a schematic diagram of H&E sections of mice treated with different compounds.

[0379] Imiquimod can stimulate the skin of mice, causing erythema, scaling, and thickened skin. From Figures 5A to 5C It can be seen that, compared with the model group, the erythema, scaling, and thickened skin of mice treated with compound I-13 were significantly improved. Figure 5A Furthermore, no significant change in mouse body weight was observed after administration, demonstrating the good safety profile of compound I-13. Figure 5B H&E sections showed that compound I-13 could alleviate inflammatory infiltration and tissue thickening of the skin in mice. Figure 5C Therefore, the oral compound I-13 can alleviate IMQ-induced skin inflammation and psoriasis-like lesions by selectively inhibiting HDAC6.

[0380] The above description is merely a preferred embodiment of this application and is not intended to limit the application in any other way. Any person skilled in the art may make changes or modifications to the disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the protection scope of this application.

Claims

1. A compound of formula (I) or a pharmaceutically acceptable salt thereof, characterized in that, The structure of the compound of formula (I) is shown below: Wherein, R1 is selected from L is selected from a bond, alkylene group, or carbonyl group; R2, R3, R4 and R5 are each independently selected from: H, alkyl, halogen, hydroxyl and -OR7; R6 is selected from: H, substituted or unsubstituted alkyl, cycloalkyl, -C(O)-R8, -C(O)NH2 and -C(S)NH2.

2. The compound according to claim 1 or a pharmaceutically acceptable salt thereof, characterized in that, L is an alkylene group, preferably C1-C6. 12 Alkylene, more preferably C1-C4 alkylene.

3. The compound according to claim 1 or 2, or a pharmaceutically acceptable salt thereof, characterized in that, The halogen is fluorine, chlorine, bromine or iodine.

4. The compound or a pharmaceutically acceptable salt thereof according to any one of claims 1-3, characterized in that, The alkyl group, R7, and R8 are each independently C1-C. 12 Alkyl groups, more preferably C1-C4 alkyl groups; The substitution is made by a halogen, preferably fluorine, chlorine, bromine or iodine; Preferably, the cycloalkyl group is C3-C. 15 The cycloalkyl group, preferably a C3-C6 cycloalkyl group.

5. The compound according to any one of claims 1-4, or a pharmaceutically acceptable salt thereof, wherein the compound is: 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-3-fluorobenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-3-chloro-N'-ethylbenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-3-bromo-N'-ethylbenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-3-iodobenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N '-Ethyl-3-methoxybenzoylhydrazine, 4-(((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2-fluorobenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-2-chloro-N'-ethylbenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-2-bromo-N'-ethylbenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2-iodobenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2-iodobenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2-iodobenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2-iodobenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethyl-2-iodobenzoylhydrazine, Heterocyclic heptan-11-yl)methyl)-N'-ethyl-2-methoxybenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacyclic heptan-11-yl)methyl)-N'-ethyl-3,5-difluorobenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacyclic heptan-11-yl)methyl)-N'-ethyl-2,6-difluorobenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,bf]azacyclic heptan-11-yl)methyl)-N'-ethyl-2,5-difluorobenzoylhydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacyclic heptan-11-yl)methyl)-N'-ethyl-2,3-difluorobenzoylhydrazine, 4-(11H-benzo[b]pyrido[4,3-f]azacyclopenten-11-carbonyl)-N'-ethylbenzohydrazine, 3-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-ethylbenzohydrazine, 4-(11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)-N'-ethylbenzohydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)benzohydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-methylbenzohydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-methylbenzohydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-methylbenzohydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-methylbenzohydrazine,3-f]azacycloheptane-11-yl)methyl)-N'-(2-fluoroethyl)benzohydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-(2,2-difluoroethyl)benzohydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-(2,2,2-trifluoroethyl)benzohydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-(2,2,2-trifluoroethyl)benzohydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-(2,2,2-trifluoroethyl)benzohydrazine, 4-((11H-benzo[b]pyrido[4 ,3-f]azacycloheptane-11-yl)methyl)-N'-(tert-butyl)benzohydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-cyclopropylbenzohydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)-N'-isopropylbenzohydrazine, 4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl) 2-(4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)benzoyl)hydrazine-1-carboxamide, 2-(4-((11H-benzo[b]pyrido[4,3-f]azacycloheptane-11-yl)methyl)benzoyl)hydrazine-1-thiocarboxamide, 4-((9H-carbazole-9-yl)methyl)-N'-ethyl-2,5-difluorobenzoylhydrazine, 4-((9H-pyrido) [2,3-b]indol-9-yl)methyl)-N'-ethyl-2,5-difluorobenzoylhydrazine, 4-((10H-benzo[b]pyrido[2,3-e][1,4]thiazin-10-yl)methyl)-N'-ethyl-2,5-difluorobenzoylhydrazine, 4-((5H-dibenzo[b,f]azacycloheptane-5-yl)methyl)-N'-ethyl-2,5-difluorobenzoylhydrazine or N'-ethyl-2,5-difluoro-4-(quinoline-8-amino)methyl)benzoylhydrazine.

6. A method for preparing the compound of any one of claims 1-5 or a pharmaceutically acceptable salt thereof, comprising the following steps:

7. The method according to claim 6, wherein, Using a compound containing R1 as a raw material, intermediate 2 is obtained by reacting it with intermediate 1 under the action of sodium hydride; or by reacting it with intermediate 1 under the action of diisopropylaminolithium; or by reacting it with intermediate 2 under the action of Pd2(dba)3; or by reacting it with intermediate 1 under the action of 4-dimethylaminopyridine. Intermediate 3 is obtained by hydrolysis of intermediate 2 as a raw material; Intermediate 4 is obtained by reacting intermediate 3 with an R6-substituted hydrazine group in the presence of 2-(7-azabenzotriazole)-N,N,N',N'-tetramethylurea hexafluorophosphate to give general formula I.

8. A pharmaceutical composition comprising the compound of any one of claims 1-5 or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable diluent or carrier.

9. The compound of any one of claims 1-5 or a pharmaceutically acceptable salt thereof, used as a medicine.

10. Use of the compound of any one of claims 1-5 or a pharmaceutically acceptable salt thereof in the preparation of an HDAC6 inhibitor or in the preparation of a treatment for diseases associated with abnormal expression of HDAC6 activity. Preferably, the diseases associated with abnormal HDAC6 activity expression include inflammatory and autoimmune diseases, tumors, neurodegenerative diseases, nervous system diseases, diabetes, and cardiovascular and cerebrovascular diseases; Preferably, the inflammatory and autoimmune diseases include inflammatory bowel disease (IBD), psoriasis, sepsis, arthritis, gout, acute lung injury, or systemic lupus erythematosus; and / or The tumors include triple-negative breast cancer, lung cancer, melanoma, esophageal cancer, prostate cancer, breast cancer, cervical cancer, ovarian cancer, gastric cancer, pancreatic cancer, bladder cancer, colorectal cancer, brain tumors, gliomas, anaplastic oligodendrogliomas, adult glioblastoma, adult anaplastic astrocytoma, bone cancer, or soft tissue sarcoma; and / or The neurodegenerative diseases mentioned include Parkinson's disease (PD), Alzheimer's disease (AD), cerebral ischemia (CI), brain injury (BI), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS), different types of spinocerebellar ataxia (SCA), epilepsy, Huntington's disease, or Pick's disease; and / or The cardiovascular and cerebrovascular diseases mentioned include stroke or atherosclerosis.

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