RU2814288C1 - Novel compounds as histone deacetylase 6 inhibitor and pharmaceutical composition containing them - Google Patents

Abstract

FIELD: medicine; pharmaceutics.

SUBSTANCE: present invention relates to a novel compound of chemical formula I, or a pharmaceutically acceptable salt thereof, where is ; each of R₄ and R₅ is independently C1-C4 alkyl; Z₅ is N-R₆ or CH₂; R₆ is C1-C4 alkyl, -C(=O)-(C1-C4 alkyl), -C (=O)-O-(C1-C4 alkyl) or 4–6 membered heterocycloalkyl having one O; L₁ is -(C1-C2 alkylene)-; is C6-C12 aryl, 5–9 membered heteroaryl having at least one N, or ; each of R₂ and R₃ independently represents H, halogen, C6-C12 aryl, 5- or 6-member heteroaryl, having N or O, 5- or 6-member heterocycloalkyl, having N, 5- or 6-member heterocycloalkenyl having N, -C(=O)-O-(C1-C4 alkyl), -C(=O)-(C1-C4 alkyl), -NH-C(=O)-(C1-C4 alkyl), -NO₂ or -NH₂, at least one H of the above R₂ and R₃ can in each case be independently substituted with halogen or C1-C4 alkyl; and n, and m in each case is independently equal to 1 or 2. Invention also relates to a pharmaceutical composition containing a compound of chemical formula I, to a method for preventing or treating diseases mediated by histone deacetylase (HDAC), and to the use of a compound of chemical formula I for preventing or treating diseases mediated by HDAC.

EFFECT: enabling development of a selective inhibitor of HDAC6, which has a zinc-binding group, with improved bioavailability, which does not cause side effects, for treating cancer, inflammatory, autoimmune and neurological diseases, neurodegenerative disorders.

10 cl, 2 tbl, 38 ex

Description

Field of technology to which the invention relates

The present invention relates to a new compound having histone deacetylase 6 (HDAC6) inhibitory activity, its stereoisomers, its pharmaceutically acceptable salts, its use in the preparation of a therapeutic drug, a pharmaceutical composition containing it, a therapeutic method using this composition and a method for its preparation.

State of the art

In cells, post-translational modification such as acetylation serves as a very important regulatory module at the center of biological processes and is also tightly controlled by a number of enzymes. As the core protein that makes up chromatin, histone functions as an axis around which DNA twists and thus promotes DNA condensation. In addition, the balance between histone acetylation and deacetylation plays a very important role in gene expression.

As an enzyme for removing the acetyl group from the lysine residue of histone protein that constitutes chromatin, histone deacetylase (HDAC) is known to be associated with gene silencing and induce cell cycle arrest, inhibition of angiogenesis, immunoregulation, apoptosis, etc. (Hassig et al., Curr. Opin. Chem. Biol. 1997, 1, 300-308). It has also been reported that inhibition of HDAC enzyme functions induces apoptosis of cancer cells by reducing the activity of factors associated with cancer cell survival and activating factors associated with cancer cell death in the body (Warrell et al., J. Natl. Cancer Inst. 1998, 90, 1621-1625).

There are 18 known HDACs in humans, which are divided into four classes based on homology to yeast HDACs. Eleven HDACs using zinc as a cofactor can be divided into three groups: class I (HDAC1, 2, 3, 8), class II (IIa: HDAC4, 5, 7, 9; IIb: HDAC6, 10) and class IV (HDAC11). In addition, seven class III HDACs (SIRT 1-7) use NAD+ as a cofactor instead of zinc (Bolden et al., Nat. Rev. Drug Discov. 2006, 5(9), 769-784).

Various HDAC inhibitors are currently in preclinical or clinical stages of development, but to date only non-selective HDAC inhibitors are known as anticancer agents. Vorinostat (SAHA) and romidepsin (FK228) have received approval as

therapeutic for cutaneous T-cell lymphoma, while panobinostat (LBH-589) received approval as a therapeutic for multiple myeloma. However, it is known that non-selective HDAC inhibitors usually cause side effects such as fatigue, nausea and the like when used in high doses (Piekarz et al., Pharmaceuticals 2010, 3, 2751-2767). Side effects are reported to be caused by HDAC class I inhibition. Due to side effects and the like, non-selective HDAC inhibitors are subject to limitations in drug development in areas other than anti-cancer agents (Witt et al., Cancer Letters 277 (2009) 8.21).

At the same time, it is reported that selective inhibition of HDAC class II will not lead to the toxicity that would occur with inhibition of HDAC class I. If selective HDAC inhibitors were developed, this would likely eliminate side effects such as toxicity, etc. caused by non-selective HDAC inhibition. Accordingly, there is a possibility that selective HDAC inhibitors could be developed as effective therapeutic agents for the treatment of various diseases (Matthias et al., Mol. Cell. Biol. 2008, 28, 1688-1701).

It is known that HDAC6, one of the lib class HDACs, is mainly present in the cytoplasm and contains the protein tubulin, respectively, participating in the deacetylation of a number of non-histone substrates (HSP90, cortactin, etc.) (Yao et al., Mol. Cell 2005, 18, 601-607). HDAC6 has two catalytic domains, where the C-terminal zinc finger domain can bind to the ubiquitinated protein. HDAC6 is known to have a number of non-histone proteins as substrates, and thus plays an important role in various diseases such as cancer, inflammatory diseases, autoimmune diseases, neurological diseases, neurodegenerative disorders and the like (Santo et al., Blood 2012 119 : 2579-258; Vishwakarma et al., International Immunopharmacology 2013, 16, 72-78; Hu et al., J. Neurol. Sci. 2011, 304, 1-8).

A structural feature common to various HDAC inhibitors includes a cap group, a linker group, and a zinc binding group (ZBG), as shown in the following structure of vorinostat. Many researchers have conducted studies on enzyme inhibitory activity and selectivity through structural modification of the cap group and linker group. In addition to these groups, the zinc-binding group is known to play a more important role in the inhibitory activity and selectivity of the enzyme (Wiest et al., J. Org. Chem. 2013 78: 5051-5065; Methot et al., Bioorg. Med. Chem. Lett. 2008, 18, 973-978).

Most of this zinc-binding group consists of hydroxamic acid or benzamide, of which hydroxamic acid derivatives exhibit strong HDAC inhibitory effects, but have problems of low bioavailability and serious side activities. Benzamide contains aniline and thus has the problem that it can produce toxic metabolites in vivo (Woster et al., Med. Chem. Commun. 2015, published online).

Accordingly, in contrast to non-selective inhibitors that have side effects, there is a need to develop a selective HDAC6 inhibitor that has a zinc-binding group with improved bioavailability without causing side effects for the treatment of cancer, inflammatory diseases, autoimmune diseases, neurological diseases, neurodegenerative diseases. violations and the like.

[Reference to prior art]

[Patent Document]

International Patent Publication WO 2011/091213 (published July 28, 2011): ACY-1215

International Patent Publication WO 2011/011186 (published January 27, 2011): Tubastatin

International Patent Publication WO 2013/052110 (published April 11, 2013): Sloan-K

International Patent Publication WO 2013/0414 07 (published March 28, 2013): Cellzome

International Patent Publication WO 2013/134 4 67 (published September 12, 2013): Kozi

International Patent Publication WO 2013/008162 (published January 17, 2013): Novartis

International Patent Publication WO 2013/080120 (published 06 June 2013): Novartis

International Patent Publication WO 2013/066835 (published May 10, 2013): Tempero

International Patent Publication WO 2013/066838 (published May 10, 2013): Tempero

International Patent Publication WO 2013/066833 (published May 10, 2013): Tempero

International Patent Publication WO 2013/066839 (published May 10, 2013): Tempero

Detailed Description of the Invention

Technical problem

One of the objects of the present invention is to provide a new compound having selective inhibitory

activity against HDAC6, its stereoisomers or pharmaceutically acceptable salts thereof.

Another object of the present invention is to provide a pharmaceutical composition containing a new compound having selective inhibitory activity against HDAC6, stereoisomers thereof or pharmaceutically acceptable salts thereof.

Another object of the present invention is to provide a method for their preparation.

Another object of the present invention is to provide a pharmaceutical composition for the prevention or treatment of diseases associated with HDAC6 activity, containing the compound, its stereoisomers or pharmaceutically acceptable salts thereof as an effective ingredient.

Another object of the present invention is to provide the use of the compound, its stereoisomers or pharmaceutically acceptable salts thereof; or a pharmaceutical composition containing them as an effective ingredient for the prevention or treatment of diseases associated with HDAC6 activity.

Another object of the present invention is to provide the use of the compound, its stereoisomers or pharmaceutically acceptable salts thereof; or a pharmaceutical composition containing them as an effective ingredient for the preparation of a medicament for the prevention or treatment of diseases associated with HDAC6 activity.

It is yet another object of the present invention to provide a method for preventing or treating diseases associated with HDAC6 activity, comprising administering a therapeutically effective amount of a compound, stereoisomers thereof, or pharmaceutically acceptable salts thereof; or a pharmaceutical composition containing them as an effective ingredient to a subject in need thereof.

Technical solution

The inventors of the present invention have discovered an oxadiazole derivative compound having histone deacetylase 6 (HDAC6) inhibitory activity and used it to inhibit or treat diseases associated with HDAC6 activity, thereby enabling the present invention.

The compound represented by formula I

The present invention provides a new compound having selective inhibitory activity against HDAC6, represented by the following chemical formula I, stereoisomers thereof or pharmaceutically acceptable salts thereof:

[Chemical formula I]

Where

each of Z ₁ - Z ₄ independently represents N or CR ₀ (here R ₀ is H or halogen);

R ₁ represents CX ₃ or CX ₂ H (here X is halogen);

is

each of R ₄ and R ₅ independently represents H or C1-C4 alkyl,

Z ₅ represents NR ₆ or CH ₂ ,

R ₆ represents H, C1-C4 alkyl, -C(=O)-(C1-C4 alkyl), -C(=O)-O-(C1-C4 alkyl) or a 4-6 membered peterocycloalkyl having one ABOUT;

L ₁ represents -(C1-C2 alkylene)-;

is a C6-C12 aryl, 5-9 membered peteroaryl having at least one N, or

each of R ₂ and R ₃ independently represents H, halogen, C1-C4 alkyl, C6-C12 aryl, 5- or 6-membered heteroaryl having N or 0, 5- or 6-membered heterocycloalkyl having N, 5- or a 6-membered heterocycloalkenyl having N, -C(=O)-O-(C1-C4 alkyl), -C(=O)-(C1-C4 alkyl), -NH-C(=O)- (C1 -C4 alkyl), -NO ₂ or -NH ₂ ,

at least one H of the above R ₂ and R ₃ may in each case be independently substituted with halogen or C1-C4 alkyl; And

n and m are in each case independently equal to 1 or 2.

In one embodiment, in Chemical Formula I above,

R ₂ and R ₃ are each independently H, halogen, C1-C4 alkyl, phenyl, furanyl, pyridinyl, C1-C4 alkyl substituted or unsubstituted piperidinyl, C1-C4 alkyl substituted or unsubstituted tetrahydropyridinyl, -C(=O)-O- (C1-C4 alkyl), C(=O)-(C1-C4 alkyl), -NH-C(=O)-(C1-C4 alkyl), -NO ₂ or -NH ₂ ,

is phenyl, indole or

If is indole or H from its NH may be replaced by -C(=O)-O-(C1-C4 alkyl) or -C(=O)-(C1-C4 alkyl), and if is phenyl, at least one H of phenyl may in each instance be independently substituted with halogen, and

n and m can be independently equal to 1 or 2 in each case.

In the present invention, the term "substituted" can mean a moiety having a substituent that replaces at least one hydrogen on a backbone carbon. The expression "substitution", "may be substituted by ~" or "substituted by ~" can be defined to include implicit terms in which the substitution matches the permissible valency of the substituted atom and substituent and produces a compound stabilized by the substitution, e.g., a compound that is not naturally modified rearrangement, cyclization, removal, etc.

In the present invention, "Cx-y" may refer to the presence of carbon atoms in the range from x to y.

In the present invention, "alkyl" may refer to a linear (or straight chain) saturated hydrocarbon group or a branched (or pendant) saturated hydrocarbon group, and includes methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert -butyl, n-pentyl, n-hexyl, n-heptyl, etc.

In the present invention, "alkylene" may refer to a divalent functional group that is formed from an alkyl group as defined above.

In the present invention, "aryl" may include a monocyclic aromatic structure or a polycyclic aromatic structure, as well as a structure in which a saturated hydrocarbon ring is fused to a monocyclic or polycyclic aromatic group. Aryl may include a phenyl group, naphthalenyl, tetrahydronaphthalenyl, anthracenyl, phenanthrenyl, pyrenyl, etc.

In the present invention, "heteroaryl" may mean a monocyclic or polycyclic heteroring in which at least one carbon atom is replaced by at least one heteroatom that is at least one of nitrogen (N) and oxygen (O) in the aryl as defined above . Heteroaryl may include, but is not limited to, pyridinyl, triazolyl, tetrazolyl, indolyl, isoindolyl, furanyl, pyrrolyl, imidazolyl, oxazolyl, isoxazolyl, pyrazinyl, pyridazinyl, pyrimidinyl, etc.

As used herein, "cycloalkyl" may refer to a saturated hydrocarbon ring, typically having a specified number of carbon atoms within the ring, and may include cyclohexyl, cycloheptanyl, cyclooctanyl, etc. In the present invention, “heterocycloalkyl” can refer to a saturated ring structure containing from one to four heteroatoms representing at least one of nitrogen (N) and oxygen (O).

In the present invention, “heterocycloalkenyl” may refer to a structure having at least one carbon-carbon double bond containing from one to four heteroatoms representing at least one of nitrogen (N) and oxygen (O).

In the present invention, "halogen" may refer to F, Cl or Br.

In the present invention, a “stereoisomer” may include a diastereomer and an optical isomer (enantiomer), wherein the optical isomer may include not only an enantiomer, but also a mixture of an enantiomer and even a racemate.

In the present invention, pharmaceutically acceptable salts may refer to salts conventionally used in the pharmaceutical industry, for example, inorganic ionic salts derived from calcium, potassium, sodium, magnesium and the like; salts of inorganic acids obtained from hydrochloric acid, nitric acid, phosphoric acid, bromic acid, iodic acid, perchloric acid, sulfuric acid and the like; salts of organic acids obtained from acetic acid, trifluoroacetic acid, citric acid, maleic acid, succinic acid, oxalic acid, benzoic acid, tartaric acid, fumaric acid, mandelic acid, propionic acid, lactic acid, glycolic acid, gluconic acid, galacturonic acid ,

glutamic acid, glutaric acid, glucuronic acid, aspartic acid, ascorbic acid, carbonic acid, vanillic acid, hydroiodic acid, etc.; sulfonic acid salts derived from methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalene sulfonic acid and the like; amino acid salts obtained from glycine, arginine, lysine, etc.; amine salts obtained from trimethylamine, triethylamine, ammonia, pyridine, picoline, etc.; and the like, however, the types of salts contemplated in the present invention are not limited to the listed salts.

In the present invention, preferred salts may include hydrochloride, phosphate, sulfate, trifluoroacetate, citrate, bromate, maleate or tartrate.

In one embodiment, the compound represented by Chemical Formula I of the present invention, stereoisomers thereof, or pharmaceutically acceptable salts thereof may include the compounds shown in Table 1 below.

Method for preparing the compound represented by chemical formula I

The present invention may provide a method for preparing the compound represented by Chemical Formula I, stereoisomers thereof, or pharmaceutically acceptable salts thereof.

The preferred method for preparing the compound is

represented by chemical formula I, its stereoisomers or pharmaceutically acceptable salts thereof is as shown in reaction formulas 1, 1-1 and 2 to 7, and even the production method modified to a level obvious to those skilled in the art is also included therein .

In each of reaction formulas 1, 1-1 and 2 to 7, R ₁ - R ₅ , Z ₁ - Z ₄ , L ₁ , m, n and X are essentially the same as defined in chemical formula I In reaction formulas 1, 1-1 and 2 to 7, "halo" can refer to the halogen F, Cl or Br. In addition, in reaction formulas 1, 1-1 and 2 to 7, "PG" may refer to a protecting group on a nitrogen atom and may include tert-butyloxycarbonyl (Boc), benzyloxycarbonyl (Cbz) or the like.

[Reaction formula 1]

The above Reaction Formula 1 shows a method for synthesizing a compound having the structure of imidazolidine-2,4-dione, where a compound of chemical formula 1-1-1 can react with a compound of chemical formula 1-1-2 and a compound of chemical formula 1-1-3 to obtaining a compound of chemical formula 1-1-4 having the structure of an aminonitrile. Thereafter, the resulting compound can be reacted with a compound of chemical formula 1-1-5 to produce a compound of chemical formula 1-1-6 having the structure of imidazolidine-2,4-dione, and then reacted with a compound of chemical formula 1-1-7 to produce compounds of the chemical formula 1-1-8.

In the present invention, the compound obtained according to the above Reaction Formula 1 may include 3, 4, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 and the like.

[Reaction formula 1-1]

The above reaction formula 1-1 refers to essentially the same chemical reaction as the above reaction formula 1, in which a compound of chemical formula 1-1-1 can react with a compound of chemical formula l-2-la and a compound of chemical formula 1-1-3 to obtain a compound of chemical formula 1-2-2a. Thereafter, the resulting compound can be reacted with a compound of chemical formula 1-1-5 to produce a compound of chemical formula 1-2-3a having the structure of imidazolidine-2,4-dione, and then reacted with a compound of chemical formula 1-1-7 to produce compounds of the chemical formula 1-2-4a. In the present invention, the compound obtained according to the above reaction formula 1-1 may include 24 and the like.

[Reaction formula 2]

In the above reaction formula 2, “R _x ” may represent a C1-C4 alkyl, a 4-6 membered heterocycloalkyl having one O, or a C(=O)-(C1-C4 alkyl). The above Reaction Formula 2 shows a method for synthesizing a compound having the structure of imidazolidine-2,4-dione, wherein the compound of chemical formula 1-1-1 can react with a compound of chemical formula 1-2-1 to which a protecting group is added and with the compound chemical formula 1-1-3 to obtain a compound of chemical formula 1-2-2 having the structure of an aminonitrile. Thereafter, the resulting compound can be reacted with a compound of chemical formula 1-1-5 to produce a compound of chemical formula 1-2-3 having the structure of imidazolidine-2,4-dione, and then reacted with a compound of chemical formula 1-1-7 to produce compounds with the chemical formula 1-2-4. The protecting group may be removed from a compound of chemical formula 1-2-4 to obtain a compound of chemical formula 1-2-5, and then a reductive amination reaction or a displacement reaction may be carried out to obtain a compound of chemical formula 1-2-6.

In the present invention, the compound obtained according to the above Reaction Formula 2 may include 5, 6, 7, 8, 21, 22, 23 and the like.

[Reaction formula 3]

The above reaction formula 3 shows a method for synthesizing a compound having the structure of imidazolidine-2,4-dione, where the compound of chemical formula 1-3-1 obtained in reaction formula 1 can be subjected to C-C coupling (Suzuki reaction) with the compound of chemical formula 1-3-2 to obtain a compound of chemical formula 1-3-3.

In the present invention, the compound obtained according to the above Reaction Formula 3 may include 25, 26, 27, 28, 29 and the like.

[Reaction formula 4]

In the above reaction formula 4, "R _a " may be C(=O)-(C1-C4 alkyl).

The above Reaction Formula 4 shows a method for synthesizing a compound having the structure of imidazolidine-2,4-dione, wherein the protecting group can be removed from the compound of chemical formula 1-4-1 having a protecting group obtained in Reaction Formula 1 to obtain the compound chemical formula 1-4-2, after which a reduction reaction can be carried out to obtain a compound of chemical formula 1-4-3. Thereafter, a reductive amination reaction or a displacement reaction may be carried out to produce a compound of chemical formula 1-4-4.

In the present invention, the compound obtained according to the above Reaction Formula 4 may include 30, 31, 32, 33, 37 and the like.

[Reaction formula 5]

In the above reaction formula 5, "R _b " may be -C(=O)-(C1-C4 alkyl).

The above reaction formula 5 shows a method for synthesizing a compound having the structure of imidazolidine-2,4-dione, where a reduction reaction can be carried out with the compound of chemical formula 1-5-1 obtained in reaction formula 1 with the addition of nitro to obtain the compound of chemical formula 1-5-2, after which the reaction can be carried out

reductive amination or substitution reaction to produce a compound of chemical formula 1-5-3.

In the present invention, the compound obtained according to the above Reaction Formula 5 may include 34, 35, 36 and the like.

[Reaction formula 6]

In the above reaction formula 6, R _c may be C1-C4 alkyl.

The above reaction formula 6 shows a method for synthesizing a compound having the structure of imidazolidine-2,4-dione, where the compound of chemical formula 1-3-1 obtained in reaction formula 1 can be subjected to C-C coupling (Suzuki reaction) with the compound of chemical formula 1-6-1 having a protecting group to obtain a compound of chemical formula 1-6-2. The protecting group may be removed from a compound of chemical formula 1-6-2 to obtain a compound of chemical formula 1-6-3, and then a reductive amination reaction or a displacement reaction may be carried out to obtain a compound of chemical formula 1-6-4. A reduction reaction can then be carried out to produce a compound of chemical formula 1-6-5.

In the present invention, the compound obtained according to the above Reaction Formula 6 may include 19, 20 and the like.

[Reaction formula 7]

In the above reaction formula, 7 alkyl may be C1-C4 alkyl.

The above Reaction Formula 7 illustrates a method for synthesizing a compound having the structure of imidazolidine-2,4-dione, wherein a compound of chemical formula 1-7-1 can be reacted with a compound of chemical formula 1-7-2 to produce a compound of chemical formula 1-7-3 , and a cyclization reaction can be carried out to obtain a compound of chemical formula 1-7-4. A compound of chemical formula 1-7-6 can be prepared through a substitution reaction between a compound of chemical formula 1-7-4 and a compound of chemical formula 1-7-5, after which the compound of chemical formula 1-7-6 can react with hydrazine with to obtain a compound of chemical formula 1-7-7, and then react with difluoroacetic anhydride and trifluoroacetic anhydride to obtain a compound of chemical formula 1-7-8. The compound of chemical formula 1-7-8 can then be subjected to a cyclization reaction with Burgess' reagent to produce a compound of chemical formula 1-7-9.

In the present invention, the compound obtained according to the above Reaction Formula 7 may include 1, 2 and the like.

Composition containing a compound represented by chemical formula I, its use and a therapeutic method using it

The present invention can provide a pharmaceutical composition for the prevention or treatment of diseases mediated by histone deacetylase (HDAC) containing a compound represented by chemical formula I, stereoisomers thereof or pharmaceutically acceptable salts thereof as an effective ingredient. Preferably, the present invention may provide a pharmaceutical composition for the prevention or treatment of diseases associated with HDAC6 activity. The above chemical formula I is the same as defined above.

The pharmaceutical composition of the present invention can selectively inhibit HDAC6, thereby exhibiting a remarkable effect in preventing or treating diseases associated with histone deacetylase 6 activity.

Histone deacetylase (HDAC)-mediated diseases, particularly diseases associated with HDAC6 activity, may include infectious diseases such as prion disease; a neoplasm such as a benign tumor (eg, myelodysplastic syndrome) or a malignant tumor (eg, multiple myeloma, lymphoma, leukemia, lung cancer, colorectal cancer, colon cancer, prostate cancer, urothelial carcinoma, breast cancer, melanoma, skin cancer , liver cancer, brain cancer, stomach cancer, ovarian cancer, pancreatic cancer, head and neck cancer, oral cancer or glioma); endocrinopathy, nutritional and metabolic diseases such as Wilson's disease, amyloidosis or diabetes; mental and behavioral disorders such as depression or Rett syndrome; neurological diseases such as central nervous system atrophy (eg, Huntington's disease, spinal muscular atrophy (SMA), spinocerebellar ataxia (SCA)), neurodegenerative disease (eg, Alzheimer's disease), movement disorder (eg, Parkinson's disease), neuropathy (eg , hereditary neuropathy (Charcot-Marie-Tooth disease), sporadic neuropathy, inflammatory neuropathy, drug-induced neuropathy), motor neuropathy (eg, amyotrophic lateral sclerosis (ALS)), demyelinating disease of the central nervous system (eg, multiple sclerosis (MS) ) or the like; ocular and ocular adnexal diseases such as uveitis; diseases of the circulatory system such as atrial fibrillation, stroke or the like; respiratory diseases such as asthma; digestive diseases such as alcoholic liver disease, inflammatory bowel disease, Crohn's disease, peptic ulcer or the like; diseases of the skin and subcutaneous tissue, such as psoriasis; musculoskeletal and connective tissue diseases such as rheumatoid arthritis, osteoarthritis, systemic lupus erythematosus (SLE) or the like; or teratosis, deformities and chromosomal aberrations such as autosomal dominant polycystic kidney disease, and may also include other symptoms or diseases associated with impaired histone deacetylase function.

The pharmaceutically acceptable salts are the same as those described in the pharmaceutically acceptable salts of the compound of the present invention.

For administration, the pharmaceutical composition of the present invention may also contain at least one type of pharmaceutically acceptable carrier in addition to the compound, its stereoisomers or its pharmaceutically acceptable salts. The pharmaceutically acceptable carrier used may include saline, sterilized water, Ringer's solution, buffered saline, dextrose solution, maltodextrin solution, glycerin, ethanol and a mixture of at least one of their ingredients, as well as other conventional additives such as antioxidants, buffering solutions, bacteriostatic agents, etc. can be added to them if necessary. In addition, diluents, dispersants, surfactants, binders and lubricants may be added to prepare injectable dosage forms such as aqueous solutions, suspensions, emulsions, etc., dragees, capsules, granules or tablets. Thus, the composition of the present invention can be patches, liquid drugs, dragees, capsules, granules, tablets, suppositories, etc. Such preparations may be prepared by the conventional method used for preparation in the art or by the method described in Remington's Pharmaceutical Science (latest edition), Mack Publishing Company, Easton PA, and such composition may be formulated into various preparations depending on each disease or component.

The composition of the present invention can be administered orally or parenterally (for example, administered intravenously, subcutaneously, intraperitoneally or topically) in accordance with the intended method, and its dose varies within a certain range depending on the patient's weight, age, gender, health status and diet, time of administration, route of administration, rate of elimination, severity of disease and the like. The daily dose of the compound of the present invention, its stereoisomers or its pharmaceutically acceptable salts may be about 1-1000 mg/kg, preferably 5-100 mg/kg, and may be administered once a day or several times a day by dividing the daily dose of the compound.

The pharmaceutical composition of the present invention may further contain at least one effective ingredient that exhibits the same or similar therapeutic effect, in addition to the compound, its stereoisomers or pharmaceutically acceptable salts thereof.

The present invention may provide a method

preventing or treating histone deacetylase (HDAC)-mediated diseases, comprising administering a therapeutically effective amount of a compound represented by the above chemical formula I, stereoisomers thereof, or pharmaceutically acceptable salts thereof; or a pharmaceutical composition containing them as an effective ingredient to a subject in need thereof. Histone deacetylase (HDAC)-mediated diseases may be diseases associated with HDAC6 activity.

As used herein, the term “therapeutically effective amount” may refer to an amount of a compound, its stereoisomers, or pharmaceutically acceptable salts thereof that is effective in the prevention or treatment of histone deacetylase (HDAC)-mediated diseases, particularly diseases associated with HDAC6 activity.

In the present invention, the term “subject” may refer to a mammal, including a human, and the term “administration” may refer to providing a given substance to a subject by any suitable means. Those skilled in the art will appreciate that the therapeutically effective dose and number of administrations for an effective ingredient of the present invention may vary depending on the desired effect.

In the present invention, the term “prevention” may refer to delaying the onset of a disease, disorder or condition. If the onset of a disease, disorder or condition is delayed for the expected period of time, the warning can be considered to have occurred.

In the present invention, the term “treatment” may refer to a treatment that partially or completely reduces, improves, mitigates, inhibits or delays the onset of a particular disease, disorder and/or condition, reduces its severity or reduces the occurrence of at least one symptom or property thereof.

In addition, the present invention may provide a method for selectively inhibiting HDAC6 by administering a therapeutically effective amount of a compound represented by the above chemical formula I, stereoisomers thereof, or pharmaceutically acceptable salts thereof; or a pharmaceutical composition containing them as an effective ingredient in mammals, including humans.

A method of preventing or treating histone deacetylase (HDAC)-mediated diseases, in particular diseases associated with HDAC6 activity, according to the present invention may include not only combating the diseases themselves before symptoms appear, but also inhibiting or eliminating such symptoms by administering a compound thereof. stereoisomers or pharmaceutically acceptable salts thereof. When treating a disease, the prophylactic or therapeutic dose of a particular active ingredient may vary depending on the nature and severity of the disease or condition and the route of administration of the active ingredient. The dose and frequency of its use may vary depending on the age, weight and reactions of the individual patient. The appropriate dosage and route of administration can be easily selected by those skilled in the art, naturally taking such factors into account. In addition, a method of preventing or treating histone deacetylase (HDAC)-mediated diseases, in particular diseases associated with HDAC6 activity, according to the present invention may also include administering a therapeutically effective amount of an additional active agent that is useful in treating the diseases, along with the compound represented by the above chemical formula I, and the additional active agent may exhibit a synergistic effect or additive effect with the compound, its stereoisomers or pharmaceutically acceptable salts thereof.

The present invention may also provide the use of the compound represented by chemical formula I, stereoisomers thereof or pharmaceutically acceptable salts thereof; or a pharmaceutical composition containing them as an effective ingredient for the prevention or treatment of histone deacetylase (HDAC)-mediated diseases.

Histone deacetylase (HDAC)-mediated diseases may be diseases associated with HDAC6 activity.

The present invention may also provide the use of the compound represented by the above chemical formula I, stereoisomers thereof, or pharmaceutically acceptable salts thereof; or a pharmaceutical composition containing them as an effective ingredient for the preparation of a medicament for the prevention or treatment of histone deacetylase (HDAC)-mediated diseases. Histone deacetylase (HDAC)-mediated diseases may be diseases associated with HDAC6 activity.

For drug preparation, the compound, its stereoisomers or pharmaceutically acceptable salts thereof may be combined with suitable adjuvants, diluents, carriers, etc., and may be formulated together with other active agents and thus exhibit a synergistic effect active components.

The substances mentioned in the use, composition and therapeutic method of the present invention are used equally, if not mutually exclusive.

Beneficial effects

According to the present invention, the compound represented by the above chemical formula I, its stereoisomers or its pharmaceutically acceptable salts have not only HDAC6 inhibitory activity, but also a surprisingly excellent effect of preventing or treating diseases associated with HDAC6 activity by selectively inhibiting HDAC6.

In addition, the compound of the invention having selective inhibitory activity against HDAC6, its stereoisomers or pharmaceutically acceptable salts thereof can be successfully used for the prevention or treatment of diseases associated with HDAC6 activity, such as cancer, inflammatory diseases, autoimmune diseases, neurological diseases or neurodegenerative disorders, etc.

Best Mode for Carrying Out the Invention

Hereinafter, the present invention will be described in more detail using the following examples and experimental examples. However, these examples are provided only for the purpose of illustrating the present invention, and accordingly, the scope of the present invention is not limited to them.

Getting a connection

A specific method for producing the compound represented by Chemical Formula I is as follows.

Example 1: Synthesis of Compound 1, 1-(4-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)-2-fluorobenzyl)-5,5-dimethyl-3-phenylimidazolidine-2,4 -dione

[Step 1] Synthesis of N'-(2,2-difluoroacetyl)-4-((5,5-dimethyl-2,4-dioxo-3-phenylimidazolidin-1-yl)methyl)-3-fluorobenzohydrazide

4-((5,5-Dimethyl-2,4-dioxo-3-phenylimidazolidin-1-yl)methyl)-3-fluorobenzohydrazide (0.119 g, 0.321 mmol) and triethylamine (0.067 ml, 0.482 mmol) were dissolved in dichloromethane ( 4 ml) at room temperature, after which 2,2-difluoroacetic anhydride (0.036 ml, 0.289 mmol) was added to the resulting solution and stirred at the same temperature. The solvent was removed from the reaction mixture under reduced pressure, after which the resulting concentrate was purified by column chromatography (SiO ₂ , 4 g cartridge; ethyl acetate/hexane=20-70%) and concentrated to give the title compound (0.053 g, 36.8 %) in the form of a colorless oil.

[Step 2] Synthesis of Compound 1

N'-(2,2-difluoroacetyl)-4-((5,5-dimethyl-2,4-dioxo-3-phenylimidazolidin-1-yl)methyl)-3-fluorobenzohydrazide (0.053 g, 0.118 mmol), prepared in step 1, and 1-methoxy-N-triethylammoniosulfonyl methanimidate (Burgess reagent, 0.042 g, 0.177 mmol) was mixed in tetrahydrofuran (4 ml) at room temperature, after which the resulting mixture was irradiated with microwaves, then heated at 150°C for 30 min, and then the reaction was completed by lowering the temperature to room temperature. The solvent was removed from the reaction mixture under reduced pressure, after which water was poured into the resulting concentrate, followed by extraction with ethyl acetate. The organic layer was washed with a saturated aqueous hydrogen carbonate solution, dehydrated using anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 4 g cartridge; ethyl acetate/hexane=0-40%) and concentrated to give the title compound (0.009 g, 17.7%) as a colorless oil.

^1H NMR (400 MHz, CDCl ₃ ) δ 7.94 (d, J=8.2 Hz, 1H), 7.88 (d, J=10.0 Hz, 1H), 7.53 ~ 7.47 (m, 4H), 7.43 ~ 7.39 (m, 1H), 6.95 (t, J=51.6 Hz, 1H), 4.77 (s, 2H); MSHP (ES) m/z 431.0 (M ⁺ +1).

Synthesis of compound 2, 1-(2-fluoro-4-(5-(trifluoromethyl)-1,3,4-oxadiazol-2-yl)benzyl)-5,5-dimethyl-3-phenylimidazolidine-2,4-dione

[Step 1] Synthesis of methyl 2-methyl-2-(3-phenylureido)propanoate

Isocyanatobenzene (1.000 g, 8.395 mmol), methyl 2-amino-2-methylpropanoate (1.418 g, 9.234 mmol) and triethylamine (1.280 ml, 9.234 mmol) were dissolved in dichloromethane (10 ml) at room temperature, after which the resulting solution was stirred at the same temperature for 8 hours. The solvent was removed from the reaction mixture under reduced pressure, after which the resulting product was used without further purification process (1,900 g, 95.8%, white solid).

[Step 2] Synthesis of 5,5-dimethyl-3-phenylimidazolidine-2,4-dione

Methyl 2-methyl-2-(3-phenylureido)propanoate (1.900 g, 8.028 mmol) obtained in step 1 and 4 M aqueous hydrochloric acid (4.00 M dioxane solution, 8.028 mL, 32.112 mmol) were dissolved in methanol (20 ml) at room temperature, after which the resulting solution was stirred at the same temperature for 12 hours. Water was added to the reaction mixture and extraction was carried out with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-30%) and concentrated to give the title compound (1,300 g, 79.3%) as a white solid.

[Step 3] Synthesis of methyl 4-((5,5-dimethyl-2,4-dioxo-3-phenylimidazolidin-1-yl)methyl)-3-fluorobenzoate

5,5-Dimethyl-3-phenylimidazolidine-2,4-dione (0.413 g, 2.022 mmol) obtained in step 2 was dissolved in N,N-dimethylformamide (15 ml) at 0°C, followed by sodium hydride (0.073 g, 3.033 mmol) was added to the resulting solution and stirred at the same temperature for 30 minutes. Methyl 4-(bromomethyl)-3-fluorobenzoate (0.500 g, 2.022 mmol) was added to the reaction mixture and further stirred at room temperature for 12 hours. Water was poured into the reaction mixture and extraction was carried out with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-30%) and concentrated to give the title compound (0.265 g, 35.4%) as a colorless oil.

[Step 4] Synthesis of 4-((5,5-dimethyl-2,4-dioxo-3-phenylimidazolidin-1-yl)methyl)-3-fluorobenzohydrazide

Methyl 4-((5,5-dimethyl-2,4-dioxo-3-phenylimidazolidin-1-yl)methyl)-3-fluorobenzoate (0.265 g, 0.715 mmol) obtained in step 3 and hydrazine monohydrate (0.676 ml , 14.310 mmol) was mixed in ethanol (10 ml), then heated at 120°C for 1 hour by irradiation with microwaves, and then the reaction was completed by lowering the temperature to room temperature. The solvent was removed from the reaction mixture under reduced pressure, after which water was poured into the resulting concentrate, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The resulting product was used without further purification process (0.220 g, 83.0%, white foamy solid).

[Step 5] Synthesis of 4-((5,5-dimethyl-2,4-dioxo-3-phenylimidazolidin-1-yl)methyl)-3-fluoro-N'-(2,2,2-trifluoroacetyl)benzohydrazide

4-((5,5-Dimethyl-2,4-dioxo-3-phenylimidazolidin-1-yl)methyl)-3-fluorobenzohydrazide (0.108 g, 0.292 mmol) obtained in step 4, trifluoroacetic anhydride (0.037 ml, 0.262 mmol) and triethylamine (0.061 ml, 0.437 mmol) were dissolved in dichloromethane (10 ml) at room temperature, after which the resulting solution was stirred at the same temperature for 1 hour. Water was poured into the reaction mixture and extraction was carried out with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; dichloromethane/dichloromethane=0-10%) and concentrated to give the title compound (0.084 g, 61.8%) as a colorless oil.

[Step 6] Synthesis of Compound 2

4-((5,5-Dimethyl-2,4-dioxo-3-phenylimidazolidin-1-yl)methyl)-3-fluoro-N'-(2,2,2-trifluoroacetyl)benzohydrazide (0.084 g, 0.180 mmol) obtained in step 5, and 1-methoxy-N-triethylammoniosulfonyl methanimidate (Burgess reagent, 0.064 g, 0.270 mmol) were mixed in tetrahydrofuran (10 ml), after which the resulting mixture was irradiated with microwaves, then heated at 150°C for 30 min, and then the reaction was completed by lowering the temperature to room temperature. Water was poured into the reaction mixture and extraction was performed with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-50%) and concentrated to give the title compound (0.040 g, 49.5%) as a colorless oil.

^1H NMR (400 MHz, CDCl ₃ ) δ 7.95 ~ 7.92 (m, 1H), 7.88 (dd, J=9.9, 1.5 Hz, 1H), 7.78 (t, J=7.7 Hz, 1H), 7.54 ~ 7.38 (m, 5H), 4.77 (s, 2H), 1.48 (s, 9H).

Synthesis of compound 3, 3-(4-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)-2-fluorobenzyl)-1-phenylimidazolidine-2,4-dione

[Step 1] Synthesis of 4-((2,5-dioxo-3-phenylimidazolidin-1-yl)methyl)-3-fluorobenzohydrazide

Methyl 4-((4,4-dimethyl-2,5-dioxo-3-phenylimidazolidin-1-yl)methyl)-3-fluorobenzoate (0.175 g, 0.511 mmol) and hydrazine monohydrate (0.497 mL, 10.224 mmol) were dissolved in ethanol (3 ml) at room temperature, after which the resulting solution was stirred at 120°C for 1 hour, and then the reaction was completed by lowering the temperature to room temperature. The precipitated solid was filtered, washed with ethanol and dried to give the title compound (0.100 g, 57.1%) as a white solid.

[Step 2] Synthesis of N'-(2,2-difluoroacetyl)-4-((2,5-dioxo-3-phenylimidazolidin-1-yl)methyl)-3-fluorobenzohydrazide

4-((2,5-Dioxo-3-phenylimidazolidin-1-yl)methyl)-3-fluorobenzohydrazide (0.100 g, 0.292 mmol) obtained in step 1 and triethylamine (0.061 ml, 0.438 mmol) were dissolved in dichloromethane ( 10 ml) at room temperature, after which 2,2-difluoroacetic anhydride (0.029 ml, 0.263 mmol) was added to the resulting solution and stirred at the same temperature for 17 hours. The precipitated solid was filtered, washed with dichloromethane and dried to obtain the above title compound (0.100 g, 81.4%) as a white solid.

[Step 3] Synthesis of Compound 3

N'-(2,2-difluoroacetyl)-4-((2,5-dioxo-3-phenylimidazolidin-1-yl)methyl)-3-fluorobenzohydrazide (0.100 g, 0.238 mmol) obtained in step 2 and 1 -methoxy-P-triethylammoniosulfonyl methanimidate (Burgess reagent, 0.085 g, 0.357 mmol) was mixed in tetrahydrofuran (3 ml) at room temperature, after which the resulting mixture was irradiated with microwaves, then heated at 150 ° C for 30 min, and then the reaction completed by lowering the temperature to room temperature. The solvent was removed from the reaction mixture under reduced pressure, after which water was poured into the resulting concentrate and extraction was carried out with dichloromethane, filtered through a plastic filter to remove the solid residue and a layer of aqueous solution, and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 4 g cartridge; ethyl acetate/hexane=5-70%) and concentrated to give the title compound (0.019 g, 19.9%) as a white solid.

^1H NMR (400 MHz, CDCl ₃ ) δ 7.89 (dd, J=4.8, 1.3 Hz, 1H), 7.87 (t, J=2.2 Hz, 1H), 7.69 ~ 7.38 (m, 6H), 7.14 (t, J=7.4 Hz, 1H), 4.79 (s, 2H), 4.61 (s, 2H).

Synthesis of compound 4, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-phenylimidazolidine-2,4-dione

1-Phenylimidazolidine-2,4-dione (0.200 g, 1.135 mmol) was dissolved in N,N-dimethylformamide (10 ml) at 0°C, after which sodium hydride (60.00%, 0.068 g, 1.703 mmol) was added to the resulting solution and stirred at the same temperature for 30 minutes. 2-(6-(Bromomethyl)pyridin-3-yl)-5-(difluoromethyl)-1,3,4-oxadiazole (0.329 g, 1.135 mmol) was added to the reaction mixture and further stirred at room temperature for 3 hours. Water was poured into the reaction mixture and extraction was performed with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-30%) and concentrated to give the title compound (0.100 g, 22.9%) as a white solid.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.27 ~ 9.26 (m, 1H), 8.39 (dd, J=8.2, 2.2 Hz, 1H), 7.61 (dd, J=7.8, 1.1 Hz, 2H), 7.54 (dd, J=8.2, 0.7 Hz, 1H), 7.44 ~ 7.40 (m, 2H), 7.20 ~ 7.18 (m, 1H), 7.08 (s, 0.25H), 6.95 (s, 0.5H), 6.82 (s, 0.25H), 5.03 (s, 2H ), 4.47 (s, 2H); MSHP (ES) m/z 386.4 (M ⁺ +1).

Synthesis of compound 5, tert-butyl-3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(3-fluorophenyl)- 2,4-dioxo-1, 3, 8-triazaspiro[4.5]decane-8-carboxylate

[Step 1] Synthesis of tert-butyl-4-((3-(4-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)-2-fluorobenzyl)-3-phenylureido)methyl)piperidine -1-carboxylate

3-Fluoroaniline (1.000 g, 8.999 mmol), tert-butyl-4-oxopiperidine-1-carboxylate (1.793 g, 8.999 mmol) and trimethylsilacarbonitrile (0.893 g, 8.999 mmol) were dissolved in acetic acid (30 ml), and the resulting the solution was stirred at 0°C for 30 minutes and then stirred at room temperature for 18 hours. A saturated aqueous solution of ammonium chloride was poured into the reaction mixture and extraction was carried out with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-30%) and concentrated to give the title compound (1.850 g, 64.4%) as a white solid.

[Step 2] Synthesis of tert-butyl-1-(3-fluorophenyl)-2,4-dioxo-1,3,8-triazaspiro[4.5]decane-8-carboxylate

Tert-butyl-4-cyano-4-((3-fluorophenyl)amino)piperidine-1-carboxylate (1.850 g, 5.792 mmol) obtained in step 1 was dissolved in dichloromethane (5 ml), after which the resulting solution was added chlorosulfonylisocyanate (1.230 g, 8.689 mmol) at 0°C and stirred for 30 minutes. B the reaction mixture was poured with 1 N. an aqueous solution of hydrochloric acid (10 ml), after which the solvent was concentrated under reduced pressure and then ethanol (15 ml) was added. The resulting mixture was stirred again at 80°C for 30 minutes, after which the solvent was concentrated under reduced pressure. The resulting mixture was then dissolved in THF (20 ml) and the pH was adjusted to 8 with 10% potassium carbonate solution, after which di-tert-butyl dicarbonate (1.896 g, 8.689 mmol) dissolved in THF (20 ml) was added and stirred for 18 hours. Thereafter, the solid was filtered to obtain the title compound (1.23 g, 59.9%) as a white solid.

[Step 3] Synthesis of Compound 5

Tert-butyl-1-(3-fluorophenyl)-2,4-dioxo-1,3,8-triazaspiro[4.5]decane-8-carboxylate (0.600 g, 1.651 mmol) obtained in step 2 was dissolved in N, N-dimethylformamide (10 ml) at 0°C, after which sodium hydride (60.00%, 0.099 g, 2.477 mmol) was added to the resulting solution and stirred at the same temperature for 30 minutes. 2-(6-(Bromomethyl)pyridin-3-yl)-5-(difluoromethyl)-1,3,4-oxadiazole (0.718 g, 2.477 mmol) was added to the reaction mixture and further stirred at room temperature for 3 hours. Water was added to the reaction mixture and extraction was carried out with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-50%) and concentrated to give the title compound (0.257 g, 27.2%) as a colorless oil.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.22 (t, J=1.1 Hz, 1H), 8.34 (dd, J=8.2, 2.2 Hz, 1H), 7.48 ~7.39 (m, 23.), 7.20 ~ 7.15 (m, 1H), 7.06 (s, 0.25H), 7.01 ~ 7.00 (m, 1H), 6, 98 (s, 0.5H), 6.99 ~ 6.94 (m, 1H), 6.92 (s, 0.25H), 4.95 (s, 2H), 4.10 - 3.95 ( m, 2H), 3.50 ~ 3.40 (m, 2H), 1.99 ~ 1.95 (m, 2H), 1.80 ~ 1.75 (m, 2H), 1.36 (s, 9H); MSHP (ES) m/z 573.4 (M ⁺ +1).

Synthesis of compound 6, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(3-fluorophenyl)-8-methyl- 1,3,8-triazaspiro[4.5]decane-2,4-dione

[Step 1] Synthesis of 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(3-fluorophenyl)-1,3 ,8-triazaspiro[4.5]decane-2,4-dione-2,2,2-trifluoroacetate

Tert-butyl-3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(3-fluorophenyl)-2,4- dioxo-1,3,8-triazaspiro[4.5]decane-8-carboxylate (0.257 g, 0.449 mmol) and trifluoroacetic acid (0.344 ml, 4.489 mmol) were dissolved in dichloromethane (30 ml) at room temperature, after which the resulting solution was stirred at the same temperature for 12 hours. The solvent was removed from the reaction mixture under reduced pressure, after which the resulting product was used without further purification process (0.250 g, 95.0%, yellow oil).

[Step 2] Synthesis of compound 6

3-((5-(5-(Difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(3-fluorophenyl)-1,3,8-triazaspiro[ 4.5]decane-2,4-dione-2,2,2-trifluoroacetate (0.200 g, 0.341 mmol) obtained in step 1, formaldehyde (0.020 g, 0.682 mmol), N,N-diisopropylethylamine (0.059 ml, 0.341 mmol ) and sodium triacetoxyborohydride (0.145 g, 0.682 mmol) were dissolved in dichloromethane (10 ml) at room temperature, after which the resulting solution was stirred at the same temperature for 2 hours. Water was poured into the reaction mixture and extraction was carried out with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; methanol/dichloromethane=0-10%) and concentrated to give the title compound (0.100 g, 60.3%) as a colorless oil.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.28 (d, J=1.4 Hz, 1H), 8.41 (dd, J=8.2, 2.2 Hz, 1H), 7.51 (d, J=8.2 Hz, 1H), 7.47 ~ 7.41 (m, 1H), 7.18 ~ 7.14 (m, 1H), 7.08 (s, 0.25H), 7.05 ~ 7.03 (m, 1H), 7.00 ~ 6.97 (m, 1H), 6.95 (s, 0.5H), 6.82 (s, 0.25H), 5, 00 (s, 2H), 3.20 ~ 2.90 (m, 4H), 2.48 (s, 3H), 2.23 ~ 2.20 (m, 2H), 2.08 ~ 2.05 ( m, 2H); MSHP (ES) m/z 487.5 (M ⁺⁺ 1).

Synthesis of compound 7, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(3-fluorophenyl)-8-(oxetane -3-yl)-1,3,8-triazaspiro[4.5]decane-2,4-dione

N'-(2, 2-difluoroacetyl)-6-((1-(3-fluorophenyl)-8-(oxetan-3-yl)-2,4-dioxo-1,3,8-triazaspiro[4,5 ]decan-3-yl)methyl)nicotinohydrazide (0.060 g, 0.110 mmol) and 1-methoxy-1\[-triethylammoniosulfonyl methanimidate (Burgess reagent, 0.052 g, 0.220 mmol) were dissolved in tetrahydrofuran (5 ml) at 80°C , after which the resulting solution was stirred at the same temperature for 13 hours, and then the reaction was completed by lowering the temperature to room temperature. Water was poured into the reaction mixture and extraction was performed with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-100%) and concentrated to give the title compound (0.020 g, 34.5%) as a colorless oil.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.28 (dd, J=2.2, 0.8 Hz, 1H), 8.39 (dd, J=8.2, 2.2 Hz, 1H) , 7.51 ~ 7.49 (m, 1H), 7.47 ~ 7.43 (m, 1H), 7.21 ~ 7.16 (m, 1H), 7.08 ~ 7.05 (m, 1H), 7.08 (s, 0.25H), 7.01 ~ 6.98 (m, 1H), 6.95 (s, 0.5H), 6.82 (s, 0.25H), 4 .99 (s, 2H), 4.66 (t, J=6.6 Hz, 2H), 4.55 (t, J=5.0 Hz, 2H), 3.61 ~ 3.58 (m, 1H), 2.74~2.66(m,4H), 2.11~2.04(m,4H).

Synthesis of compound 8, 3-((5-(5-(difluoromethyl)-1, 3, 4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(3-fluorophenyl)-8-isopropyl- 1,3,8-triazaspiro[4.5]decane-2,4-dione

3-((5-(5-(Difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(3-fluorophenyl)-1,3,8-triazaspiro[ 4.5]decane-2,4-dione-2,2,2-trifluoroacetate (0.200 g, 0.341 mmol), acetone (0.051 ml, 0.682 mmol), N,N-diisopropylethylamine (0.059 ml, 0.341 mmol) and sodium triacetoxyborohydride ( 0.145 g, 0.682 mmol) was dissolved in dichloromethane (10 ml) at room temperature, after which the resulting solution was stirred at the same temperature for 18 hours. Water was poured into the reaction mixture and extraction was carried out with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; methanol/dichloromethane=0-10%) and concentrated to give the title compound (0.110 g, 62.8%) as a white foamy solid.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.29 (dd, J=2.l, 0.7 Hz, 1H), 8.41 (dd, J=8.2, 2.2 Hz, 1H) , 7.53 ~ 7.50 (m, 1H), 7.47 ~ 7.43 (m, 1H), 7.19 ~ 7.16 (m, 1H), 7.08 (s, 0.25H) , 7.01 ~ 7.00 (m, 1H), 6.99 ~ 6.98 (m, 1H), 6.96 (s, 0.5H), 6.83 (s, 0.25H), 5 .00 (s, 2H), 3.28 ~ 3.25 (m, 1H), 3.10 ~ 3.08 (m, 4H), 2.33 ~ 2.30 (m, 2H), 2.09 ~2.06 (m, 2H), 1.18 ~1.13 (m, 6H); MSHP (ES) m/z 515.5 (M ⁺ +1).

Synthesis of compound 9, 3-((5-(5-(difluoromethyl)-1, 3, 4-oxadiazol-2-yl)pyrimidin-2-yl)methyl)-1-phenylimidazolidine-2,4-dione

1-Phenylimidazolidin-2,4-dione (0.300 g, 1.703 mmol), 2-(2-(bromomethyl)pyrimidin-5-yl)-5-(difluoromethyl)-1,3,4-oxadiazole (0.496 g, 1.703 mmol) and potassium carbonate (0.353 g, 2.554 mmol) were dissolved in N,N-dimethylformamide (5 ml) at 80°C, after which the resulting solution was stirred at the same temperature for 12 hours and then the reaction was completed by lowering the temperature to room temperature temperature. Water was poured into the reaction mixture and extraction was performed with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-50%) and concentrated to give the title compound (0.110 g, 16.7%) as a yellow solid.

^1H NMR (400 MHz, _CDCl3 ) δ 9.7 (s, 2H), 7.65 ~ 7.62 (m, 2H), 7.46 ~ 7.42 (m, 2H), 7.23 ~ 7.19 (m, 1H), 7.10 (s, 0.25H), 6.97 (s, 0.5H), 6.84 (s, 0.25H), 5.18 (s, 2H) , 4.52 (s, 2H); MSHP (ES) m/z 387.3 (M ⁺ +1).

Synthesis of compound 10, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(3-fluorophenyl)-5,5- dimethylimidazolidine-2,4-dione

[Step 1] Synthesis of 2-((3-fluorophenyl)amino)-2-methylpropanenitrile

3-Fluoroaniline (1.000 g, 8.999 mmol), trimethylsilacarbonitrile (0.893 g, 8.999 mmol) and propan-2-one (0.523 g, 8.999 mmol) were dissolved in acetone (20 ml) at room temperature, after which the resulting solution was stirred at that at the same temperature for 12 hours. A saturated aqueous solution of ammonium chloride was poured into the reaction mixture and extraction was carried out with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 40 g cartridge; ethyl acetate/hexane=0-20%) and concentrated to give the title compound (1.240 g, 77.3%) as a white solid.

[Step 2] Synthesis of 1-(3-fluorophenyl)-5,5-dimethylimidazolidine-2,4-dione

2-(3-Fluorophenyl)-2-methylpropanenitrile (1.240 g, 7.598 mmol) obtained in step 1 and chlorosulfonylisocyanate (1.613 g, 11.397 mmol) were dissolved in dichloromethane (10 ml) at room temperature, and the resulting solution stirred at the same temperature for 1 hour. 1 N was poured into the reaction mixture. an aqueous solution of hydrochloric acid (10 ml), after which the solvent was concentrated under reduced pressure and then ethanol (15 ml) was added. The resulting mixture was stirred again at 80°C for 30 minutes, after which the solvent was concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-30%) and concentrated to give the title compound (0.880 g, 52.1%) as a white solid.

[Step 3] Synthesis of Compound 10

1-(3-Fluorophenyl)-5,5-dimethylimidazolidin-2,4-dione (0.100 g, 0.450 mmol) obtained in step 2, 2-(6-(bromomethyl)pyridin-3-yl)-5-( difluoromethyl)-1,3,4-oxadiazole (0.144 g, 0.495 mmol) and potassium carbonate (0.124 g, 0.900 mmol) were dissolved in N,N-dimethylformamide (10 ml), after which the resulting solution was stirred at 50°C for 18 hours and then further stirred at room temperature for 18 hours. Water was poured into the reaction mixture and extraction was carried out with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-80%) and concentrated to give the title compound (0.130 g, 67.0%) as a white solid.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.26 (t, J=1.1 Hz, 1H), 8.37 (dd, J=8.2, 2.2 Hz, 1H), 7.49 (d, J=8.2 Hz, 1H), 7.43 ~ 7.40 (m, 1H), 7.14 ~ 7.06 (m, 3H), 7.08 (s, 0.25H), 6.95 (s, 0.5H), 6.82 (s, 0.25H), 5.00 (s, 2H), 1.55 (s, 6H); MSHP (ES) m/z 432.3 (M ⁺ +1).

Synthesis of compound 11, 1-(3-bromophenyl)-3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5- dimethylimidazolidine-2,4-dione

[Step 1] Synthesis of 2-((3-bromophenyl)amino)-2-methylpropanenitrile

3-Bromaniline (2.000 g, 11.626 mmol), trimethylsilacarbonitrile (1.153 g, 11.626 mmol) and propan-2-one (0.675 g, 11.626 mmol) were dissolved in acetone (20 ml) at room temperature, after which the resulting solution was stirred at at the same temperature for 12 hours. A saturated aqueous solution of ammonium chloride was poured into the reaction mixture and extraction was carried out with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 40 g cartridge; ethyl acetate/hexane=0-20%) and concentrated to give the title compound (2.200 g, 79.1%) as a brown oil.

[Step 2] Synthesis of 1-(3-bromophenyl)-5,5-dimethylimidazolidine-2,4-dione

2-(3-Bromophenyl)-2-methylpropanenitrile (2.200 g, 9.817 mmol) obtained in step 1 and chlorosulfonylisocyanate (2.084 g, 14.726 mmol) were dissolved in dichloromethane (10 ml) at room temperature, after which the resulting solution was stirred at at the same temperature for 1 hour. 1 N was poured into the reaction mixture. an aqueous solution of hydrochloric acid (10 ml), after which the solvent was concentrated under reduced pressure and then ethanol (15 ml) was added. The resulting mixture was stirred again at 80°C for 30 minutes, after which the solvent was concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-30%) and concentrated to give the title compound (1.500 g, 54.0%) as a white solid.

[Step 3] Synthesis of compound 11

1-(3-Bromophenyl)-5,5-dimethylimidazolidin-2,4-dione (0.892 g, 3.150 mmol) obtained in step 2, 2-(6-(bromomethyl)pyridin-3-yl)-5-( difluoromethyl)-1,3,4-oxadiazole (1.005 g, 3.466 mmol) and potassium carbonate (0.871 g, 6.301 mmol) were dissolved in N,N-dimethylformamide (10 ml), after which the resulting solution was stirred at 50°C for 18 hours and then further stirred at room temperature for 18 hours. Water was poured into the reaction mixture and extraction was carried out with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-80%) and concentrated to give the title compound (1.100 g, 70.9%) as a yellow oil.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.30 (t, J=1.1 Hz, 1H), 8.41 (dd, J=8.2, 2.2 Hz, 1H), 7.57 ~ 7.55 (m, 1H), 7.51 ~ 7.49 (m, 1H), 7.36 (t, J=8.0 Hz, 1H), 7.30 ~ 7.27 (m, 2H ), 7.09 (s, 0.25H), 6.95 (s, 0.5H), 6.83 (s, 0.25H), 5.03 (s, 2H), 1.59 (s, 6H); MSHP (ES) m/z 494.2 (M ⁺ +1).

Synthesis of compound 12, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(4-fluorophenyl)-5,5- dimethylimidazolidine-2,4-dione

[Step 1] Synthesis of 2-((4-fluorophenyl)amino)-2-methylpropanenitrile

4-Fluoroaniline (1.000 g, 8.999 mmol), trimethylsilacarbonitrile (0.893 g, 8.999 mmol) and propan-2-one (0.523 g, 8.999 mmol) were dissolved in acetone (20 ml) at room temperature, after which the resulting solution was stirred at at the same temperature for 12 hours. A saturated aqueous solution of ammonium chloride was poured into the reaction mixture and extraction was carried out with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 40 g cartridge; ethyl acetate/hexane=0-20%) and concentrated to give the title compound (0.535 g, 33.4%) as a white solid.

[Step 2] Synthesis of 1-(4-fluorophenyl)-5,5-dimethylimidazolidine-2,4-dione

2-(4-Fluorophenyl)-2-methylpropanenitrile (0.530 g, 3.248 mmol) obtained in step 1 and chlorosulfonylisocyanate (0.689 g, 4.871 mmol) were dissolved in dichloromethane (10 ml) at room temperature, after which the resulting solution was stirred at at the same temperature for 1 hour. 1 N was poured into the reaction mixture. an aqueous solution of hydrochloric acid (10 ml), after which the solvent was concentrated under reduced pressure and then ethanol (15 ml) was added. The resulting mixture was stirred again at 80°C for 30 minutes, after which the solvent was concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-30%) and concentrated to give the title compound (0.330 g, 45.7%) as a white solid.

[Step 3] Synthesis of compound 12

1-(4-Fluorophenyl)-5,5-dimethylimidazolidin-2,4-dione (0.100 g, 0.450 mmol) obtained in step 2, 2-(6-(bromomethyl)pyridin-3-yl)-5-( difluoromethyl)-1,3,4-oxadiazole (0.144 g, 0.495 mmol) and potassium carbonate (0.124 g, 0.900 mmol) were dissolved in N,N-dimethylformamide (10 ml), after which the resulting solution was stirred at 50°C for 18 hours and then further stirred at room temperature for 18 hours. Water was poured into the reaction mixture and extraction was carried out with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-80%) and concentrated to give the title compound (0.110 g, 56.7%) as a white solid.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.27 (t, J=1.1 Hz, 1H), 8.38 (dd, J=8.2, 2.2 Hz, 1H), 7.49 (d, J=8.2 Hz, 1H), 7.30 ~ 7.26 (m, 2H), 7.17 ~ 7.13 (m, 2H), 7.08 (s, 0.25H), 6.95 (s, 0.5H), 6.82 (s, 0.25H), 5.01 (s, 2H), 1.52 (s, 6H); MSHP (ES) m/z 432.3 (M ⁺ +1).

Synthesis of compound 13, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(2,b-difluorophenyl)-5, 5-dimethylimidazolidine-2,4-dione

[Step 1] Synthesis of 2-((2,6-difluorophenyl)amino)-2-methylpropanenitrile

2,6-Difluoroaniline (0.781 ml, 7.745 mmol), trimethylsilacarbonitrile (0.973 ml, 7.745 mmol) and propan-2-one (0.569 ml, 7.745 mmol) were dissolved in acetic acid (10 ml) at room temperature, and the resulting solution stirred at the same temperature for 18 hours. The solvent was removed from the reaction mixture under reduced pressure, after which hexane (20 ml) and ethyl acetate (10 ml) were added to the resulting concentrate and stirred to filter off the precipitated solid, washed with hexane and dried to obtain the title compound (0.330 g, 21.7%) as a white solid.

[Step 2] Synthesis of 1-(2,6-difluorophenyl)-5,5-dimethylimidazolidine-2,4-dione

2-((2,6-Difluorophenyl)amino)-2-methylpropanenitrile (0.330 g, 1.682 mmol) obtained in step 1 and chlorosulfonylisocyanate (0.357 g, 2.523 mmol) were dissolved in dichloromethane (50 ml), and the resulting solution stirred at 0°C for 30 minutes and then stirred at room temperature for 18 hours. 1 N was poured into the reaction mixture. an aqueous solution of hydrochloric acid (10 ml), after which the solvent was concentrated under reduced pressure and then ethanol (30 ml) was added. The resulting mixture was stirred again at 80°C for 30 minutes, after which the solvent was concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-50%) and concentrated to give the title compound (0.100 g, 24.8%) as a white solid.

[Step 3] Synthesis of compound 13

1-(2,6-Difluorophenyl)-5,5-dimethylimidazolidin-2,4-dione (0.100 g, 0.416 mmol) obtained in step 2, 2-(6-(bromomethyl)pyridin-3-yl)-5 -(difluoromethyl)-1,3,4-oxadiazole (0.121 g, 0.416 mmol) and potassium carbonate (0.115 g, 0.833 mmol) were dissolved in N,N-dimethylformamide (5 ml) at 80°C, after which the resulting solution was stirred at the same temperature for 18 hours and then the reaction was completed by lowering the temperature to room temperature. The solvent was removed from the reaction mixture under reduced pressure, after which water was poured into the resulting concentrate, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-50%) and concentrated to give the title compound (0.150 g, 80.2%) as a white solid.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.30 (dd, J=2.2, 0.8 Hz, 1H), 8.40 (dd, J=8.2, 2.2 Hz, 1H) , 7.48 ~ 7.39 (m, 2H), 7.09 ~ 7.05 (m, 2H), 7.08 (s, 0.25H), 6.95 (s, 0.5H), 6 .82 (s, 0.25H), 5.04 (s, 2H), 1.54 (s, 6H); MSHP (ES) m/z 450.2 (M ⁺ +1).

Synthesis of compound 14, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(2,4-difluorophenyl)-5, 5-dimethylimidazolidine-2,4-dione

[Step 1] Synthesis of 2-((2,4-difluorophenyl)amino)-2-methylpropanenitrile

2,4-Difluoroaniline (1.000 g, 7.745 mmol), trimethylsilacarbonitrile (0.768 g, 7.745 mmol) and propan-2-one (0.450 g, 7.745 mmol) were dissolved in acetic acid (10 ml) at room temperature, and the resulting solution stirred at the same temperature for 18 hours. The solvent was removed from the reaction mixture under reduced pressure, after which hexane (20 ml) and ethyl acetate (10 ml) were added to the resulting concentrate and stirred to filter off the precipitated solid, washed with hexane and dried to obtain of the title compound (1.000 g, 65.8%) as a white solid.

[Step 2] Synthesis of 1-(2,4-difluorophenyl)-5,5-dimethylimidazolidine-2,4-dione

2-((2,4-Difluorophenyl)amino)-2-methylpropanenitrile (1.000 g, 5.097 mmol) obtained in step 1 and chlorosulfonylisocyanate (1.082 g, 7.645 mmol) were dissolved in dichloromethane (50 ml), and the resulting solution stirred at 0°C for 30 minutes and then stirred at room temperature for 18 hours. 1 N was poured into the reaction mixture. an aqueous solution of hydrochloric acid (10 ml), after which the solvent was concentrated under reduced pressure and then ethanol (30 ml) was added. The resulting mixture was stirred again at 80°C for 30 minutes, after which the solvent was concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/pexane=0-50%) and concentrated to give the title compound (0.700 g, 57.2%) as a white solid.

[Step 3] Synthesis of compound 14

1-(2,4-Difluorophenyl)-5,5-dimethylimidazolidin-2,4-dione (0.100 g, 0.416 mmol) obtained in step 2, 2-(6-(bromomethyl)pyridin-3-yl)-5 -(difluoromethyl)-1,3,4-oxadiazole (0.121 g, 0.416 mmol) and potassium carbonate (0.115 g, 0.833 mmol) were dissolved in N,N-dimethylformamide (5 ml) at 80°C, after which the resulting solution was stirred at the same temperature for 18 hours and then the reaction was completed by lowering the temperature to room temperature. The solvent was removed from the reaction mixture under reduced pressure, after which water was poured into the resulting concentrate, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-50%) and concentrated to give the title compound (0.130 g, 69.5%) as a white solid.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.30 (d, J=2.2 Hz, 1H), 8.40 (dd, J=8.2, 2.2 Hz, 1H), 7.49 (d, J=8.2 Hz, 1H), 7.31 ~ 7.28 (m, 1H), 7.08 (s, 0.25H), 7.04 ~ 6.99 (m, 2H), 6.95 (s, 0.5H), 6.82 (s, 0.25H), 5.03 (s, 2H), 1.52 (s, 6H); MSHP (ES) m/z 450.2 (M ⁺ +1).

Synthesis of compound 15, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(2,3-difluorophenyl)-5, 5-dimethylimidazolidine-2,4-dione

[Step 1] Synthesis of 2-((2,3-difluorophenyl)amino)-2-methylpropanenitrile

2,3-Difluoroaniline (1.000 g, 7.745 mmol), trimethylsilacarbonitrile (0.768 g, 7.745 mmol) and propan-2-one (0.450 g, 7.745 mmol) were dissolved in acetic acid (10 ml) at room temperature, and the resulting solution stirred at the same temperature for 18 hours. The solvent was removed from the reaction mixture under reduced pressure, after which pexane (20 ml) and ethyl acetate (10 ml) were added to the resulting concentrate and stirred to filter off the precipitated solid, washed with hexane and dried to obtain the title compound (1.100 g, 72.4%) as a white solid.

[Step 2] Synthesis of 1-(2,3-difluorophenyl)-5,5-dimethylimidazolidine-2,4-dione

2-((2,3-Difluorophenyl)amino)-2-methylpropanenitrile (1.100 g, 5.607 mmol) obtained in step 1 and chlorosulfonylisocyanate (1.190 g, 8.410 mmol) were dissolved in dichloromethane (50 ml), and the resulting solution stirred at 0°C for 30 minutes and then stirred at room temperature for 18 hours. 1 N was poured into the reaction mixture. an aqueous solution of hydrochloric acid (10 ml), after which the solvent was concentrated under reduced pressure and then ethanol (30 ml) was added. The resulting mixture was stirred again at 80°C for 30 minutes, after which the solvent was concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-50%) and concentrated to give the title compound (0.800 g, 59.4%) as a white solid.

[Step 3] Synthesis of compound 15

1-(2,3-Difluorophenyl)-5,5-dimethylimidazolidin-2,4-dione (0.100 g, 0.416 mmol) obtained in step 2, 2-(6-(bromomethyl)pyridin-3-yl)-5 -(difluoromethyl)-1,3,4-oxadiazole (0.121 g, 0.416 mmol) and potassium carbonate (0.115 g, 0.833 mmol) were dissolved in N,N-dimethylformamide (5 ml) at 80°C, after which the resulting solution was stirred at the same temperature for 18 hours and then the reaction was completed by lowering the temperature to room temperature. The solvent was removed from the reaction mixture under reduced pressure, after which water was poured into the resulting concentrate, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/pexane=0-50%) and concentrated to give the title compound (0.150 g, 80.2%) as a white solid.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.30 (dd, J=3.0, 1.7 Hz, 1H), 8.41 (dd, J=8.2, 2.2 Hz, 1H) , 7.50 (dd, J=8.2, 0.7 Hz, 1H), 7.31 ~ 7.28 (m, 1H), 7.21 ~ 7.19 (m, 1H), 7.12 ~ 7.08 (m, 1H), 7.08 (s, 0.25H), 6.95 (s, 0.5H), 6.82 (s, 0.25H), 5.04 (s, 2H ), 1.54 (s, 6H); MSHP (ES) m/z 450.2 (M ⁺ +1).

Synthesis of compound 16, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(3,4-difluorophenyl)-5, 5-dimethylimidazolidine-2,4-dione

[Step 1] Synthesis of 2-((3,4-difluorophenyl)amino)-2-methylpropanenitrile

3,4-Difluoroaniline (1.000 g, 7.745 mmol), trimethylsilacarbonitrile (0.768 g, 7.745 mmol) and propan-2-one (0.450 g, 7.745 mmol) were dissolved in acetic acid (10 ml) at room temperature, and the resulting solution stirred at the same temperature for 18 hours. The solvent was removed from the reaction mixture under reduced pressure, after which hexane (20 ml) and ethyl acetate (10 ml) were added to the resulting concentrate and stirred to filter off the precipitated solid, washed with hexane and dried to obtain the title compound (0.700 g, 46.1%) as a white solid.

[Step 2] Synthesis of 1-(3,4-difluorophenyl)-5,5-dimethylimidazolidine-2,4-dione

2-((3,4-Difluorophenyl)amino)-2-methylpropanenitrile (0.700 g, 3.568 mmol) obtained in step 1 and chlorosulfonylisocyanate (0.757 g, 5.352 mmol) were dissolved in dichloromethane (50 ml), and the resulting solution stirred at 0°C for 30 minutes and then stirred at room temperature for 18 hours. 1 N was poured into the reaction mixture. an aqueous solution of hydrochloric acid (10 ml), after which the solvent was concentrated under reduced pressure and then ethanol (30 ml) was added. The resulting mixture was stirred again at 80°C for 30 minutes, after which the solvent was concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-50%) and concentrated to give the title compound (0.450 g, 52.5%) as a white solid.

[Step 3] Synthesis of compound 16

1-(3,4-Difluorophenyl)-5,5-dimethylimidazolidin-2,4-dione (0.100 g, 0.416 mmol) obtained in step 2, 2-(6-(bromomethyl)pyridin-3-yl)-5 -(difluoromethyl)-1,3,4-oxadiazole (0.121 g, 0.416 mmol) and potassium carbonate (0.115 g, 0.833 mmol) were dissolved in N,N-dimethylformamide (5 ml) at 80°C, after which the resulting solution was stirred at the same temperature for 18 hours and then the reaction was completed by lowering the temperature to room temperature. The solvent was removed from the reaction mixture under reduced pressure, after which water was poured into the resulting concentrate, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-50%) and concentrated to give the title compound (0.130 g, 69.5%) as a white solid.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.28 (t, J=1.1 Hz, 1H), 8.40 (dd, J=8.2, 2.2 Hz, 1H), 7.51 ~7.49(m, 1H), 7.28~7.19(m, 2H), 7.09~7.08(m, 1H), 7.08(s, 0.25H), 6.95 (s, 0.5H), 6.82 (s, 0.25H), 5.01 (s, 2H), 1.55 (s, 6H); MSHP (ES) m/z 450.4 (M ⁺ +1).

Synthesis of compound 17, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(3,5-difluorophenyl)-5, 5-dimethylimidazolidine-2,4-dione

[Step 1] Synthesis of 2-((3,5-difluorophenyl)amino)-2-methylpropanenitrile

3,5-Difluoroaniline (1.000 g, 7.745 mmol), trimethylsilacarbonitrile (0.768 g, 7.745 mmol) and propan-2-one (0.450 g, 7.745 mmol) were dissolved in acetic acid (10 ml) at room temperature, and the resulting solution stirred at the same temperature for 18 hours. The solvent was removed from the reaction mixture under reduced pressure, after which hexane (20 ml) and ethyl acetate (10 ml) were added to the resulting concentrate and stirred to filter off the precipitated solid, washed with hexane and dried to obtain the title compound (1.100 g, 72.4%) as a white solid.

[Step 2] Synthesis of 1-(3,5-difluorophenyl)-5,5-dimethylimidazolidine-2,4-dione

2-((3,5-Difluorophenyl)amino)-2-methylpropanenitrile (1.100 g, 5.607 mmol) obtained in step 1 and chlorosulfonylisocyanate (1.190 g, 8.410 mmol) were dissolved in dichloromethane (50 ml), and the resulting solution stirred at 0°C for 30 minutes and then stirred at room temperature for 18 hours. 1 N was poured into the reaction mixture. an aqueous solution of hydrochloric acid (10 ml), after which the solvent was concentrated under reduced pressure and then ethanol (30 ml) was added. The resulting mixture was stirred again at 80°C for 30 minutes, after which the solvent was concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/pexane=0-50%) and concentrated to give the title compound (0.800 g, 59.4%) as a white solid.

[Step 3] Synthesis of compound 17

1-(3,5-Difluorophenyl)-5,5-dimethylimidazolidin-2,4-dione (0.100 g, 0.416 mmol) obtained in step 2, 2-(6-(bromomethyl)pyridin-3-yl)-5 -(difluoromethyl)-1,3,4-oxadiazole (0.121 g, 0.416 mmol) and potassium carbonate (0.115 g, 0.833 mmol) were dissolved in N,N-dimethylformamide (5 ml) at 80°C, after which the resulting solution was stirred at the same temperature for 18 hours and then the reaction was completed by lowering the temperature to room temperature. The solvent was removed from the reaction mixture under reduced pressure, after which water was poured into the resulting concentrate, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-50%) and concentrated to give the title compound (0.110 g, 58.8%) as a white solid.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.28 (t, J=1.1 Hz, 1H), 8.41 (dd, J=8.2, 2.2 Hz, 1H), 7.51 (d, J=8.2 Hz, 1H), 7.09 ~ 7.08 (m, 1H), 7.08 (s, 0.25H), 6.97 ~ 6.94 (m, 2H), 6.95 (s, 0.5H), 6.82 (s, 0.25H), 5.02 (s, 2H), 1.61 (s, 6H); MSHP (ES) m/z 450.2 (M ⁺ +1).

Synthesis of compound 18, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethyl-1-phenylimidazolidin-2, 4-dione

[Step 1] Synthesis of 2-methyl-2-(phenylamino)propanenitrile

Aniline (0.980 ml, 10.738 mmol), trimethylsilacarbonitrile (1.065 g, 10.738 mmol) and propan-2-one (0.624 g, 10.738 mmol) were dissolved in acetic acid (10 ml) at room temperature, after which the resulting solution was stirred at the same temperature for 18 hours. The solvent was removed from the reaction mixture under reduced pressure, after which hexane (20 ml) and ethyl acetate (10 ml) were added to the resulting concentrate and stirred to filter off the precipitated solid, washed with hexane and dried to obtain the title compound (1.100 g, 63.9%) as a white solid.

[Step 2] Synthesis of 5,5-dimethyl-1-phenylimidazolidine-2,4-dione

2-Methyl-2-(phenylamino)propanenitrile (1.100 g, 6.866 mmol) obtained in step 1 and chlorosulfonylisocyanate (1.458 g, 10.298 mmol) were dissolved in dichloromethane (50 ml), after which the resulting solution was stirred at 0°C in for 30 minutes and then stirred at room temperature for 18 hours. B the reaction mixture was poured with 1 N. an aqueous solution of hydrochloric acid (10 ml), after which the solvent was concentrated under reduced pressure and then ethanol (30 ml) was added. The resulting mixture was stirred again at 80°C for 30 minutes, after which the solvent was concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-50%) and concentrated to give the title compound (0.600 g, 42.8%) as a white solid.

[Step 3] Synthesis of compound 18

5,5-Dimethyl-1-phenylimidazolidin-2,4-dione (0.100 g, 0.490 mmol) obtained from step 2,2-(6-(bromomethyl)pyridin-3-yl)-5-(difluoromethyl)-1 ,3,4-oxadiazole (0.142 g, 0.490 mmol) and potassium carbonate (0.135 g, 0.979 mmol) were dissolved in N,N-dimethylformamide (5 ml) at 80°C, after which the resulting solution was stirred at the same temperature for 18 hours onwards, the reaction was completed by lowering the temperature to room temperature. The solvent was removed from the reaction mixture under reduced pressure, after which water was poured into the resulting concentrate, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/pexane=0-50%) and concentrated to give the title compound (0.080 g, 39.5%) as a white solid.

^1H NMR (400 MHz, _CDCl3 ) δ 9.26~9.25 (m, 1H), 8.37~8.34 (m, 1H), 7.49~7.38 (m, 4H), 7.31 ~ 7.23 (m, 2H), 7.08 (s, 0.25H), 6.95 (s, 0.5H), 6.82 (s, 0.25H), 5.02 ( s, 2H), 1.52 (s, 6H); MSHP (ES) m/z 414.2 (M ⁺ +1).

Synthesis of compound 19, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethyl-1-(3-( 1-methyl-1,2,3,b-tetrahydropyridin-4-yl)phenyl)imidazolidine-2,4-dione

[Step 1] Synthesis of tert-butyl-4-(3-(3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5 ,5-dimethyl-2,4-dioxoimidazolidin-1-yl)phenyl)-3,6-dihydropyridine-1(2H)-carboxylate

1-(3-Bromophenyl)-3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethylimidazolidin-2, 4-dione (0.200 g, 0.406 mmol), tert-butyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3,6-dihydropyridin-1(2H )-carboxylate (0.251 g, 0.813 mmol), [1,1'-bis(di-tert-butylphosphino)ferrocene] palladium(II) dichloride (0.026 g, 0.041 mmol) and cesium carbonate (0.199 g, 0.609 mmol) were mixed in a mixture of 1,2-dichloroethane (6 ml)/water (2 ml), after which the resulting mixture was irradiated with microwaves, heated at 100°C for 20 minutes and the reaction was completed by lowering the temperature to room temperature. Water was poured into the reaction mixture and extraction was performed with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-70%) and concentrated to give the title compound (0.140 g, 58.0%) as a colorless oil.

[Step 2] Synthesis of 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethyl-1-(3- (1,2,3,6-tetrahydropyridin-4-yl)phenyl)imidazolidin-2,4-dione-2,2,2-trifluoroacetate

Tert-butyl-4-(3-(3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethyl- 2,4-Dioxoimidazolidin-1-yl)phenyl)-3,6-dihydropyridine-1(2H)-carboxylate (0.140 g, 0.235 mmol) obtained in step 1 and trifluoroacetic acid (0.180 ml, 2.354 mmol) were dissolved in dichloromethane (10 ml) at room temperature, after which the resulting solution was stirred at the same temperature for 18 hours. The solvent was removed from the reaction mixture under reduced pressure, after which the resulting product was used without further purification process (0.140 g, 97.7%, brown butter).

[Step 3] Synthesis of compound 19

3-((5-(5-(Difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethyl-1-(3-(1,2, 3,6-tetrahydropyridin-4-yl)phenyl)imidazolidin-2,4-dione-2,2,2-trifluoroacetate (0.080 g, 0.131 mmol) obtained in step 2, formaldehyde (0.008 g, 0.263 mmol), N ,N-diisopropylethylamine (0.023 ml, 0.131 mmol) and sodium triacetoxyborohydride (0.056 g, 0.263 mmol) were dissolved in dichloromethane (5 ml) at room temperature, after which the resulting solution was stirred at the same temperature for 18 hours. The reaction mixture was poured water and extraction was carried out with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; methanol/dichloromethane=0-10%) and concentrated to give the title compound (0.040 g, 59.8%) as a colorless oil.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.29 (t, J=1.1 Hz, 1H), 8.39 (dd, J=8.2, 2.2 Hz, 1H), 7.50 ~7.48 (m, 1H), 7.41 ~ 7.39 (m, 2H), 7.29 ~ 7.28 (m, 1H), 7.20 ~ 7.18 (m, 1H), 7 .08 (s, 0.25N), 6.95 (s, 0.5N), 6.82 (s, 0.25N), 6.10 ~ 6.08 (m, 1H), 5.02 (s , 2H), 3.16 - 3.15 (m, 2H), 2.70 ~ 2.69 (m, 2H), 2.61 ~ 2.60 (m, 2H), 2.43 (s, 3H ), 1.53 (s, 6H).

Synthesis of compound 20, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethyl-1-(3-( 1-methylpiperidin-4-yl)phenyl)imidazolidine-2,4-dione

3-((5-(5-(Difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethyl-1-(3-(1-methyl- 1,2,3,6-tetrahydropyridin-4-yl)phenyl)imidazolidine-2,4-dione (0.034 g, 0.067 mmol) was dissolved in methanol (10 ml) at room temperature, after which 10% Pd/C was slowly added (60 mg) and stirred for 18 hours in the presence of an attached hydrogen cylinder at the same temperature. The reaction mixture was filtered through a pad of celite to remove solids, after which the solvent was removed from the resulting filtrate under reduced pressure and the resulting product was used without further purification (0.028 g, 82.0%, colorless oil).

^1H NMR (400 MHz, CDCl ₃ ) δ d 9.30 ~ 9.29 (m, 1H), 8.40 (dd, J=8.2, 2.2 Hz, 1H), 7.50 (d , J=8.2 Hz, 1H), 7.41 ~ 7.37 (m, 1H), 7.29 ~ 7.27 (m, 1H), 7.16 ~ 7.14 (m, 2H), 7.08 (s, 0.25H), 6.95 (s, 0.5H), 6.82 (s, 0.25H), 5.02 (s, 2H), 3.20 ~ 3.18 ( m, 2H), 2.62 ~ 2.55 (m, 1H), 2.45 (s, 3H), 2.29 ~ 2.25 (m, 2H), 2.02 ~ 1.90 (m, 4H), 1.52 (s, 6H); MSHP (ES) m/z 511.4 (M ⁺ +1).

Synthesis of compound 21, 7-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-2-methyl-5-phenyl-2,5, 7-triazaspiro[3.4]octane-b,8-dione

[Step 1] Synthesis of benzyl 3-cyano-3-(phenylamino)azetidine-1-carboxylate

Aniline (1.961 ml, 21.475 mmol), trimethylsilacarbonitrile (2.131 g, 21.475 mmol) and benzyl 3-oxoazetidine-1-carboxylate (4.407 g, 21.475 mmol) were dissolved in acetic acid (20 ml) at room temperature, and the resulting solution stirred at the same temperature for 18 hours. The solvent was removed from the reaction mixture under reduced pressure, after which ethyl acetate (10 ml) and hexane (20 ml) were added to the resulting concentrate and stirred to filter off the precipitated solid, washed with hexane and dried to obtain the title compound (4.700 g, 71.2%) as a white solid.

[Step 2] Synthesis of benzyl 6,8-dioxo-5-phenyl-2,5,7-triazaspiro[3.4]octane-2-carboxylate

Benzyl 3-cyano-3-(phenylamino)azetidine-1-carboxylate (4.700 g, 15.292 mmol) obtained in step 1 and chlorosulfonylisocyanate (3.246 g, 22.938 mmol) were dissolved in dichloromethane (50 ml), and the resulting solution stirred at 0°C for 30 minutes and then stirred at room temperature for 18 hours. 1 N was poured into the reaction mixture. an aqueous solution of hydrochloric acid (10 ml), after which the solvent was concentrated under reduced pressure and then ethanol (30 ml) was added. The resulting mixture was stirred again at 80°C for 30 minutes, after which the solvent was concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-50%) and concentrated to give the title compound (2.200 g, 40.9%) as a white solid.

[Step 3], Synthesis of benzyl-7-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-6,8-dioxo-5- phenyl 2,5,7-triazaspiro[3.4]octane-2-carboxylate

Benzyl 6,8-dioxo-5-phenyl-2,5,7-triazaspiro[3,4]octane-2-carboxylate (0.500 g, 1.423 mmol) obtained in step 2, 2-(6-(bromomethyl) pyridin-3-yl)-5-(difluoromethyl)-1,3,4-oxadiazole (0.413 g, 1.423 mmol) and potassium carbonate (0.393 g, 2.846 mmol) were dissolved in N,N-dimethylformamide (5 ml) at 80 °C, after which the resulting solution was stirred at the same temperature for 18 hours and then the reaction was completed by lowering the temperature to room temperature. The solvent was removed from the reaction mixture under reduced pressure, after which water was poured into the resulting concentrate, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-50%) and concentrated to give the title compound (0.600 g, 75.2%) as a white solid.

[Step 4] Synthesis of 7-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5-phenyl-2,5,7-triazaspiro [3.4]octane-6,8-dione

Benzyl-7-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-6,8-dioxo-5-phenyl-2,5, 7-Triazaspiro[3.4]octane-2-carboxylate (0.600 g, 1.070 mmol) obtained in step 3 was dissolved in methanol (10 ml) at room temperature, after which 10% Pd/C (60 mg) was slowly added and stirred at the same temperature for 18 hours in the presence of an attached hydrogen cylinder. The reaction mixture was filtered through a pad of celite to remove solids, after which the solvent was removed from the resulting filtrate under reduced pressure and the resulting product was used without further purification (0.450 g, 98.6%, colorless oil).

[Step 5] Synthesis of compound 21

7-((5-(5-(Difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5-phenyl-2,5,7-triazaspiro[3.4]octane- 6,8-dione (0.150 g, 0.352 mmol) obtained in step 4, formaldehyde (37.00% solution, 0.053 ml, 0.704 mmol) and sodium triacetoxyborohydride (0.149 g, 0.704 mmol) were dissolved in dichloromethane (10 ml) at room temperature, after which the resulting solution was stirred at the same temperature for 18 hours. Water was poured into the reaction mixture and extraction was carried out with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; methanol/dichloromethane=0-10%) and concentrated to give the title compound (0.100 g, 64.5%) as a colorless oil.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.24 (d, J=2.2 Hz, 1H), 8.36 (dd, J=8.2, 2.2 Hz, 1H), 7.53 ~ 7.42 (m, 6H), 7.08 (s, 0.25H), 6.95 (s, 0.5H), 6.82 (s, 0.25H), 4.99 (s, 2H ), 3.80 ~ 3.73 (m, 4H), 2.31 (s, 3H).

Synthesis of compound 22, 7-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-2-isopropyl-5-phenyl-2,5, 7-triazaspiro[3.4]octane-6,8-dione

7-((5-(5-(Difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5-phenyl-2,5,7-triazaspiro[3,4] Octane-b,8-dione (0.100 g, 0.235 mmol), acetone (0.035 ml, 0.469 mmol) and sodium triacetoxyborohydride (0.099 g, 0.469 mmol) were dissolved in dichloromethane (10 ml) at room temperature, after which the resulting solution was stirred at at the same temperature for 18 hours. Water was poured into the reaction mixture and extraction was carried out with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; methanol/dichloromethane=0-10%) and concentrated to give the title compound (0.070 g, 63.7%) as a colorless oil.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.24 (t, J=1.1 Hz, 1H), 8.36 (dd, J=8.2, 2.2 Hz, 4H), 7.51 ~ 7.39 (m, 6H), 7.08 (s, 1H), 6.95 (s, 1H), 6.82 (s, 1H), 4.98 (s, 2H), 3.84 ( s, 4H), 2.58 ~ 2.55 (m, 1H), 0.91 ~ 0.87 (m, 6H).

Synthesis of compound 23, 2-acetyl-7-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5-phenyl-2,5, 7-triazaspiro[3.4]octane-b,8-dione

7-((5-(5-(Difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5-phenyl-2,5,7-triazaspiro[3,4] Octane-6,8-dione (0.124 g, 0.291 mmol), acetyl chloride (0.041 ml, 0.582 mmol) and N,N-diisopropylethylamine (0.101 ml, 0.582 mmol) were dissolved in dichloromethane (5 ml) at room temperature, after which the resulting the solution was stirred at the same temperature for 18 hours. Water was poured into the reaction mixture and extraction was carried out with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; methanol/dichloromethane=0-10%) and concentrated to give the title compound (0.100 g, 73.4%) as a colorless oil.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.26 (t, J=1.1 Hz, 1H), 8.40 (dd, J=8.2, 2.2 Hz, 1H), 7.55 ~ 7.39 (m, 6H), 7.08 (s, 0.25H), 6.95 (s, 0.5H), 6.82 (s, 0.25H), 5.03 (s, 2H ), 4.62 ~ 4.48 (m, 2H), 4.42 ~ 4.33 (m, 2H), 1.85 (s, 3H).

Synthesis of compound 24, 7-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5-phenyl-5,7-diazaspiro[3.4] octane-6,8-dione

[Step 1] Synthesis of 1-(phenylamino)cyclobutane-1-carbonitrile

Aniline (0.980 ml, 10.738 mmol), cyclobutanone (0.753 g, 10.738 mmol) and trimethylsilacarbonitrile (1.065 g, 10.738 mmol) were dissolved in acetic acid (20 ml) at room temperature, after which the resulting solution was stirred at the same temperature for 18 h. The solvent was removed from the reaction mixture under reduced pressure, after which water was poured into the resulting concentrate and then extraction was carried out with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-30%) and concentrated to give the title compound (1.200 g, 64.9%) as a white solid.

[Step 2] Synthesis of 5-phenyl-5,7-diazaspiro[3.4]octane-6,8-dione

1-(Phenylamino)cyclobutane-1-carbonitrile (1.000 g, 5.806 mmol) obtained in step 1 and chlorosulfonylisocyanate (0.761 ml, 8.709 mmol) were dissolved in dichloromethane (20 ml) at room temperature, after which the resulting solution was stirred at at the same temperature for 12 hours. After this, 1 M HCl (10 ml) was added to the reaction mixture, after which the reaction was completed by removing the solvent. Ethanol (10 ml) was added to the reaction mixture and stirred at 80°C for 1 hour. The solvent was removed from the reaction mixture under reduced pressure, after which ethyl acetate (20 ml) and pexane (10 ml) were added to the resulting concentrate and stirred to filter the precipitated solid, washed with hexane and dried to obtain the title compound (0.950 g, 75.7%) as a white solid.

[Stage 3] Synthesis of compound 24

5-Phenyl-5,7-diazaspiro[3,4]octane-6,8-dione (0.100 g, 0.462 mmol) obtained in step 2 was dissolved in N,N-dimethylformamide (20 ml) at 0°C, after which sodium hydride (60.00%, 0.022 g, 0.555 mmol) was added to the resulting solution and stirred at the same temperature for 30 minutes. 2-(6-(Bromomethyl)pyridin-3-yl)-5-(difluoromethyl)-1,3,4-oxadiazole (0.134 g, 0.462 mmol) was added to the reaction mixture and further stirred at room temperature for 2 hours. Water was poured into the reaction mixture and extraction was performed with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 40 g cartridge; ethyl acetate/hexane=0-50%) and concentrated to give the title compound (0.130 g, 66.1%) as a yellow oil.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.30 ~ 9.26 (m, 1H), 8.37 (dd, J=8.2, 2.2 Hz, 1H), 7.53 ~ 7, 43(m, 4H), 7.33~7.31(m, 2H), 7.08(s, 0.25H), 6.95(s, 0.5H), 6.82(s, 0. 25H), 5.00 (s, 2H), 2.59 ~ 2.42 (m, 4H), 2.23 ~ 2.04 (m, 2H), 1.69 ~ 1.63 (m, 2H) .

Synthesis of compound 25, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(4-(furan-3-yl) phenyl)-5,5-dimethylimidazolidine-2,4-dione

[Step 1] Synthesis of 2-((4-bromophenyl)amino)-2-methylpropanenitrile

4-Bromaniline (3.000 g, 17.439 mmol), propan-2-one (1.013 g, 17.439 mmol) and trimethylsilacarbonitrile (1.730 g, 17.439 mmol) were dissolved in acetic acid (10 ml) at room temperature, after which the resulting solution was stirred at at the same temperature for 12 hours. The solvent was removed from the reaction mixture under reduced pressure, after which ethyl acetate (10 ml) and hexane (20 ml) were added to the resulting concentrate and stirred to filter off the precipitated solid, washed with hexane and dried to obtain the above title compound (2.700 g, 64.7%) as a white solid.

[Step 2] Synthesis of 1-(4-bromophenyl)-5,5-dimethylimidazolidine-2,4-dione

2-((4-Bromophenyl)amino)-2-methylpropanenitrile (2.740 g, 11.459 mmol) obtained in step 1 and chlorosulfonylisocyanate (1.502 ml, 17.188 mmol) were dissolved in dichloromethane (5 ml) at room temperature, after which the resulting the solution was stirred at the same temperature for 18 hours. 1M HCl (10 ml) was added to the reaction mixture to concentrate the organic layer, after which ethanol (20 ml) was added and stirred at 80°C for 1 hour. After this, the solvent was removed from the reaction mixture under reduced pressure, after which ethyl acetate (20 ml) and hexane (30 ml) were added to the resulting concentrate and stirred to filter off the precipitated solid, washed with hexane and dried to obtain the target compound (2.5 g, 77.1% ) as a white solid.

[Step 3] Synthesis of 1-(4-bromophenyl)-3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5 -dimethylimidazolidine-2,4-dione

1-(4-Bromophenyl)-5,5-dimethylimidazolidin-2,4-dione (1.000 g, 3.532 mmol) obtained in step 2, 2-(6-(bromomethyl)pyridin-3-yl)-5-( difluoromethyl)-1,3,4-oxadiazole (1.025 g, 3.532 mmol) and potassium carbonate (0.976 g, 7.064 mmol) were dissolved in N,N-dimethylformamide (30 ml) at 50°C, after which the resulting solution was stirred at at the same temperature for 12 hours and then the reaction was completed by lowering the temperature to room temperature. Water was added to the reaction mixture and extraction was carried out with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 40 g cartridge; ethyl acetate/pexane=0-50%) and concentrated to give the title compound (1.300 g, 74.8%) as a yellow solid.

[Step 4] Synthesis of compound 25

1-(4-Bromophenyl)-3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethylimidazolidin-2, 4-dione (0.150 g, 0.305 mmol) obtained in step 3, furan-3-ylboronic acid (0.051 g, 0.457 mmol), [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium (II, 0.020 g, 0.030 mmol) and cesium carbonate (0.149 g, 0.457 mmol) were mixed in a mixture of 1,4-dioxane (6 ml)/water (2 ml), after which the resulting mixture was irradiated with microwaves, then heated at 100 ° C for 20 min and further the reaction was completed by lowering the temperature to room temperature. The solvent was removed from the reaction mixture under reduced pressure, after which water was poured into the resulting concentrate, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; methanol/dichloromethane=0-10%) and concentrated to give the title compound (0.022 g, 15.1%) as a brown oil.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.30 (dd, J=2.2, 0.8 Hz, 1H), 8.40 (dd, J=8.2, 2.2 Hz, 1H) , 7.77 ~ 7.74 (m, 2H), 7.52 ~ 7.49 (m, 2H), 7.35 ~ 7.32 (m, 2H), 7.08 (s, 0.25H) , 6.95 (s, 0.5H), 6.82 (s, 0.25H), 6.72 (dd, J=3.4, 0.7 Hz, 1H), 6.51 (dd, J =3.4, 1.8 Hz, 1H), 5.04 (s, 2H), 1.56 (s, 6H); MSHP (ES) m/z 480.3 (M ⁺ +1).

Synthesis of compound 26, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethyl-1-(4-( pyridin-4-yl)phenyl)imidazolidine-2,4-dione

1-(4-Bromophenyl)-3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethylimidazolidin-2, 4-dione (0.150 g, 0.305 mmol), pyridin-4-ylboronic acid (0.056 g, 0.457 mmol), [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium (II, 0.020 g, 0.030 mmol) and cesium carbonate (0.149 g, 0.457 mmol) was mixed in 1,4-dioxane (6 ml)/water (2 ml), after which the resulting mixture was irradiated with microwaves, then heated at 100 ° C for 20 minutes and then the reaction was completed by lowering the temperature to room temperature. The solvent was removed from the reaction mixture under reduced pressure, after which water was poured into the resulting concentrate, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; methanol/dichloromethane=0-10%) and concentrated to give the title compound (0.015 g, 10.0%) as a brown oil.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.29 (dd, J=2.2, 0.8 Hz, 1H), 8.70 (dd, J=4.5, 1.6 Hz, 2H) , 8.39 (dd, J=8.2, 2.2 Hz, 1H), 7.73 ~ 7.71 (m, 2H), 7.52 ~ 7.50 (m, 3H), 7.47 ~ 7.45 (m, 2H), 7.08 (s, 0.25H), 6.95 (s, 0.5H), 6.82 (s, 0.25H), 5.04 (s, 2H ), 1.60 (s, 6H); MSHP (ES) m/z 491.2 (M ⁺ +1).

Synthesis of compound 27, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethyl-1-(4-( pyridin-3-yl) phenyl)imidazolidine-2,4-dione

1-(4-Bromophenyl)-3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethylimidazolidin-2, 4-dione (0.150 g, 0.305 mmol), pyridin-3-ylboronic acid (0.056 g, 0.457 mmol), [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium (II, 0.020 g, 0.030 mmol) and cesium carbonate (0.149 g, 0.457 mmol) was mixed in 1,4-dioxane (6 ml)/water (2 ml), after which the resulting mixture was irradiated with microwaves, then heated at 100 ° C for 20 minutes and then the reaction was completed by lowering the temperature to room temperature. The solvent was removed from the reaction mixture under reduced pressure, after which water was poured into the resulting concentrate, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified using column chromatography (SiO ₂ , 12 g cartridge;

methanol/dichloromethane=0-10%) and concentrated to give the title compound (0.030 g, 20.1%) as a brown oil.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.30 ~ 9.29 (m, 1H), 8.87 ~ 8.86 (m, 1H), 8.64 (dd, J=4.8, 1 .6 Hz, 1H), 8.40 (dd, J=8.2, 2.2 Hz, 1H), 7.91 ~ 7.88 (m, 1H), 7.68 ~ 7.65 (m, 2H), 7.52 (d, J=8.2 Hz, 1H), 7.46 ~ 7.38 (m, 3H), 7.08 (s, 0.25H), 6.95 (s, 0 ,5H), 6.82 (s, 0.25H), 5.04 (s, 2H), 1.60 (s, 6H); MSHP (ES) m/z 491.3 (M ⁺ +1).

Synthesis of compound 28, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(3'-fluoro-[1,1 '-biphenyl]-4-yl)-5,5-dimethylimidazolidine-2,4-dione

1-(4-Bromophenyl)-3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethylimidazolidin-2, 4-dione (0.150 g, 0.305 mmol), (3-fluorophenyl)boronic acid (0.064 g, 0.457 mmol), [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium (II, 0.020 g, 0.030 mmol) and cesium carbonate (0.149 g, 0.457 mmol) were mixed in a mixture of 1,4-dioxane (6 ml)/water (2 ml), after which the resulting mixture was irradiated with microwaves, then heated at 100 ° C for 20 min and then the reaction was completed by lowering the temperature to room temperature. The solvent was removed from the reaction mixture under reduced pressure, after which water was poured into the resulting concentrate, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; methanol/dichloromethane=0-10%) and concentrated to give the title compound (0.060 g, 38.8%) as a brown oil.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.31 ~ 9.30 (m, 1H), 8.40 (dd, J=8.2, 2.2 Hz, 1H), 7.67 ~ 7, 64 (m, 2H), 7.52 (d, J=8.2 Hz, 1H), 7.45 ~ 7.28 (m, 5H), 7.11 ~ 7.07 (m, 1H), 7 .08 (s, 0.25H), 6.95 (s, 0.5H), 6.82 (s, 0.25H), 5.05 (s, 2H), 1.60 (s, 6H); MSHP (ES) m/z 508.2 (M ⁺ +1).

Synthesis of compound 29, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(2'-fluoro-[1,1 '-biphenyl]-4-yl)-5,5-dimethylimidazolidine-2,4-dione

1-(4-Bromophenyl)-3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethylimidazolidin-2, 4-dione (0.150 g, 0.305 mmol), (2-fluorophenyl)boronic acid (0.064 g, 0.457 mmol), [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium (II, 0.020 g, 0.030 mmol) and carbonate cesium (0.149 g, 0.457 mmol) was mixed in 1,4-dioxane (6 ml)/water (2 ml), after which the resulting mixture was irradiated with microwaves, then heated at 100 ° C for 20 min and then the reaction was completed by reducing temperature to room temperature. The solvent was removed from the reaction mixture under reduced pressure, after which water was poured into the resulting concentrate, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; methanol/dichloromethane=0-10%) and concentrated to give the title compound (0.060 g, 38.8%) as a brown oil.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.30 ~ 9.29 (m, 1H), 8.40 (dd, J=8.2, 2.2 Hz, 1H), 7.66 ~ 7, 63(m, 2H), 7.52~7.33(m, 5H), 7.26~7.17(m, 2H), 7.08(s, 0.25H), 6.95(s, 0.5H), 6.82 (s, 0.25H), 5.04 (s, 2H), 1.60 (s, 6H); MSHP (ES) m/z 508.2 (M ⁺ +1).

Synthesis of compound 30, tert-butyl-4-(3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethyl -2,4-dioxoimidazolidin-1-yl)-1H-indole-1-carboxylate

[Step 1] Synthesis of tert-butyl-4-((2-cyanopropan-2-yl)amino)-1H-indole-1-carboxylate

Tert-butyl-4-amino-1H-indole-1-carboxylate (1.680 g, 7.233 mmol), propan-2-one (0.420 g, 7.233 mmol) and trimethylsilacarbonitrile (0.718 g, 7.233 mmol) were dissolved in acetic acid (30 ml) at room temperature, after which the resulting solution was stirred at the same temperature for 18 hours. The solvent was removed from the reaction mixture under reduced pressure, after which ethyl acetate (10 ml) and hexane (20 ml) were added to the resulting concentrate and stirred to filter the precipitated solid, washed with hexane and dried to obtain the title compound (1.930 g, 89.1%) as a white solid.

[Step 2] Synthesis of tert-butyl 4-(5,5-dimethyl-2,4-dioxoimidazolidin-1-yl)-1H-indole-1-carboxylate

Tert-butyl-4-((2-cyanopropan-2-yl)amino)-1H-indole-1-carboxylate (1.930 g, 6.447 mmol) obtained in step 1 and chlorosulfonylisocyanate (1.369 g, 9.670 mmol) were dissolved in dichloromethane (30 ml) at room temperature, after which the resulting solution was stirred at the same temperature for 18 hours. 1 M HCl (10 ml) was poured into the reaction mixture and the solvent was concentrated under reduced pressure. Thereafter, the resulting concentrate was dissolved in ethanol (20 ml) and then stirred at 80°C for 1 hour. The reaction temperature was lowered to room temperature, after which the solvent was removed under reduced pressure. The reaction mixture was then dissolved in THF (20 ml), after which 10% K ₂ CO ₃ solution (10 ml) was added to adjust the pH to 8, and then di-tert-butyl dicarbonate (2.111 g, 9.670 mmol) was added and stirred for 18 hours. Water was poured into the reaction mixture and extraction was carried out with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-30%) and concentrated to give the title compound (0.250 g, 11.3%) as a white solid.

[Step 3] Synthesis of compound 30

Tert-butyl 4-(5,5-dimethyl-2,4-dioxoimidazolidin-1-yl)-1H-indole-1-carboxylate (0.200 g, 0.582 mmol) obtained in step 2, 2-(6-( Bromomethyl)pyridin-3-yl)-5-(difluoromethyl)-1,3,4-oxadiazole (0.169 g, 0.582 mmol) and potassium carbonate (0.161 g, 1.165 mmol) were dissolved in N,N-dimethylformamide (10 ml) at 45°C, after which the resulting solution was stirred at the same temperature for 18 hours and then the reaction was completed by lowering the temperature to room temperature. Water was poured into the reaction mixture and extraction was performed with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-50%) and concentrated to give the title compound (0.110 g, 34.2%) as a white solid.

^1H NMR (400 MHz, CDCl ₃ ) 9.33 (d, J=1.6 Hz, 1H), 8.38 (dd, J=8.2, 2.2 Hz, 1H), 8.25 ~ 8.23 (m, 1H), 7.66 (d, J=3.8 Hz, 1H), 7.52 ~ 7.50 (m, 1H), 7.38 (t, J=8.0 Hz , 1H), 7.16 (dd, J=7.6, 0.6 Hz, 1H), 7.09 (s, 0.25H), 6.96 (s, 0.5H), 6.83 ( s, 0.25H), 6.56 (dd, J=3.8, 0.5 Hz, 1H), 5.06 (s, 2H), 1.67 (s, 9H), 1.53 (s , 6H).

Synthesis of compound 31, tert-butyl-4-(3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethyl -2,4-dioxoimidazolidin-1-yl)indoline-1-carboxylate

[Step 1] Synthesis of tert-butyl 4-((2-cyanopropan-2-yl)amino)indoline-1-carboxylate

Tert-butyl-4-aminoindoline-1-carboxylate (2.300 g, 9.816 mmol), propan-2-one (0.570 g, 9.816 mmol) and trimethylsilacarbonitrile (0.974 g, 9.816 mmol) were dissolved in acetic acid (30 ml) at room temperature temperature, after which the resulting solution was stirred at the same temperature for 18 hours. The solvent was removed from the reaction mixture under reduced pressure, after which ethyl acetate (10 ml) and hexane (20 ml) were added to the resulting concentrate and stirred to filter off the precipitated solid, washed with hexane and dried to obtain the title compound (2.800 g, 94.6%) as a white solid.

[Step 2] Synthesis of tert-butyl 4-(5,5-dimethyl-2,4-dioxoimidazolidin-1-yl)indoline-1-carboxylate

Tert-butyl-4-((2-cyanopropan-2-yl)amino)indoline-1-carboxylate (2.800 g, 9.290 mmol) obtained in step 1, and chlorosulfonylisocyanate (1.972 g, 13.935 mmol), and di-tert β-butyl dicarbonate (3.041 g, 13.935 mmol) was dissolved in dichloromethane (30 ml) at room temperature, after which the resulting solution was stirred at the same temperature for 18 hours. Water was poured into the reaction mixture and extraction was carried out with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-30%) and concentrated to give the title compound (0.490 g, 15.3%) as a white solid.

[Step 3] Synthesis of compound 31

Tert-butyl 4-(5,5-dimethyl-2,4-dioxoimidazolidin-1-yl)indoline-1-carboxylate (0.485 g, 1.404 mmol) prepared in step 2, 2-(6-(bromomethyl)pyridine -3-yl)-5-(difluoromethyl)-1,3,4-oxadiazole (0.407 g, 1.404 mmol) and potassium carbonate (0.388 g, 2.808 mmol) were dissolved in N,N-dimethylformamide (10 ml) at 45° C, after which the resulting solution was stirred at the same temperature for 18 hours and then the reaction was completed by lowering the temperature to room temperature. Water was poured into the reaction mixture and extraction was performed with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/pexane=0-50%) and concentrated to give the title compound (0.660 g, 84.8%) as a yellow foamy solid.

¹ H NMR (400 MHz, CDCl ₃ ) δ 9.28 (dd, J=2.2, 0.7 Hz, 1H), 8.40 (dd, J=8.2, 2.2 Hz, 1H) , 7.95 (b. s, 1H), 7.50 (dd, J=8.2, 0.7 Hz, 1H), 7.28 ~ 7.26 (m, 1H), 7.08 (s , 0.25H), 6.95 (s, 0.5H), 6.82 (s, 0.25H), 6.85 ~ 6.83 (m, 1H), 5.02 (s, 2H), 4.04 ~ 4.00 (m, 2H), 3.10 ~ 3.00 (m, 2H), 1.58 ~ 1.54 (m, 15H).

Synthesis of compound 32, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(1H-indol-4-yl) - 5,5-dimethylimidazolidine-2,4-dione

Tert-butyl-4-(3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethyl-2,4 -Dioxoimidazolidin-1-yl)-1H-indole-1-carboxylate (0.258 g, 0.467 mmol) and trifluoroacetic acid (0.358 ml, 4.669 mmol) were dissolved in dichloromethane (10 ml) at room temperature, after which the resulting solution was stirred at that the same temperature for 18 hours. The solvent was removed from the reaction mixture under reduced pressure, after which a saturated aqueous solution of sodium hydroxide carbonate was poured into the resulting concentrate, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting product was used without further purification process (0.200 g, 94.7%, gray solid).

¹ H NMR (400 MHz, DMSO-d ₆ ) 9.21 (d, J=1.9 Hz, 1H), 8.48 (dd, J=8.2, 2.2 Hz, 1H), 7, 72 (s, 0.25H), 7.69 (d, J=8.2 Hz, 1H), 7.59 (s, 0.5H), 7.50 (d, J=8.1 Hz, 1H ), 7.46 (s, 0.25H), 7.40 (t, J=2.8 Hz, 1H), 6.99 (d, J=7.0 Hz, 1H), 6.42 (t , J=2.2 Hz, 1H), 5.75 (s, 1H), 4.96 (s, 2H), 1.42 (s, 6H).

Synthesis of compound 33, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(indolin-4-yl)-5, 5-dimethylimidazolidine-2,4-dione

Tert-butyl-4-(3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethyl-2,4 -Dioxoimidazolidin-1-yl)indoline-1-carboxylate (0.670 g, 1.208 mmol) and trifluoroacetic acid (0.925 ml, 12.082 mmol) were dissolved in dichloromethane (10 ml) at room temperature, after which the resulting solution was stirred at the same temperature in for 18 hours. The solvent was removed from the reaction mixture under reduced pressure, after which a saturated aqueous solution of sodium hydrogen carbonate was poured into the resulting concentrate, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting product was used without further purification process (title compound, 0.500 g, 91.1%, yellow foamy solid).

^1H NMR (400 MHz, CDCl ₃ ) δ 9.28 (t, J=1.1 Hz, 1H), 8.39 (dd, J=8.2, 2.2 Hz, 1H), 7.50 ~ 7.47 (m, 1H), 7.08 (dd, J=8.1, 7.6 Hz, 1H), 7.08 (s, 0.25H), 6.95 (s, 0.5H ), 6.82 (s, 0.25H), 6.67 (d, J=7.8 Hz, 1H), 6.58 ~ 6.55 (m, 1H), 5.04 (s, 2H) , 3.62 ~ 3.56 (m, 2H), 3.01 ~ 2.97 (m, 2H), 1.58 (s, 6H).

Synthesis of compound 34, 3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethyl-1-(3-nitrophenyl) )imidazolidine-2,4-dione

[Step 1] Synthesis of 2-methyl-2-((3-nitrophenyl)amino)propanenitrile

3-Nitroaniline (3.000 p, 21.719 mmol), propan-2-one (1.261 g, 21.719 mmol) and trimethylsilacarbonitrile (2.155 g, 21.719 mmol) were dissolved in acetic acid (30 ml) at room temperature, after which the resulting solution was stirred at at the same temperature for 18 hours. The solvent was removed from the reaction mixture under reduced pressure, after which ethyl acetate (10 ml) and hexane (20 ml) were added to the resulting concentrate and stirred to filter off the precipitated solid, washed with hexane and dried to obtain the above title compound (4.000 g, 89.7%) as a yellow solid.

[Step 2] Synthesis of 5,5-dimethyl-1-(3-nitrophenyl)imidazolidine-2,4-dione

2-Methyl-2-((3-nitrophenyl)amino)propanenitrile (4.000 g, 19.491 mmol) obtained in step 1 and chlorosulfonylisocyanate (4.138 g, 29.237 mmol) were dissolved in dichloromethane (5 ml) at room temperature, then the resulting solution was stirred at the same temperature for 18 hours. 1 M HCl (10 ml) was poured into the reaction mixture and the solvent was concentrated under reduced pressure. Thereafter, the resulting concentrate was dissolved in ethanol (20 ml) and then stirred at 80°C for 1 hour. The precipitated solid was filtered, washed with hexane and dried to obtain the title compound (4.300 g, 88.5%) as yellow solid matter.

[Step 3] Synthesis of compound 34

5,5-Dimethyl-1-(3-nitrophenyl)imidazolidin-2,4-dione (1.000 g, 4.012 mmol) obtained in step 2, 2-(6-(bromomethyl)pyridin-3-yl)-5- (difluoromethyl)-1,3,4-oxadiazole (1.164 g, 4.012 mmol) and potassium carbonate (1.109 g, 8.025 mmol) were dissolved in N,N-dimethylformamide (20 ml) at 45°C, after which the resulting solution was stirred at at the same temperature for 18 hours and then the reaction was completed by lowering the temperature to room temperature. Water was added to the reaction mixture and extraction was carried out with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 40 g cartridge; ethyl acetate/hexane=0-50%) and concentrated to give the title compound (1,400 g, 76.1%) as a foamy white solid.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.30 (d, J=1.6 Hz, 1H), 8.42 (dd, J=8.2, 2.2 Hz, 1H), 8.28 ~8.25 (m, 2H), 7.76 ~ 7.73 (m, 1H), 7.69 ~ 7.65 (m, 1H), 7.53 ~ 7.51 (m, 1H), 7 .08 (s, 0.25H), 6.95 (s, 0.5H), 6.82 (s, 0.25H), 5.05 (s, 2H), 1.63 (s, 6H).

Synthesis of compound 35, 1-(3-aminophenyl)-3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5- dimethylimidazolidine-2,4-dione

3-((5-(5-(Difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethyl-1-(3-nitrophenyl)imidazolidin-2 ,4-dione (1.400 g, 3.054 mmol) was dissolved in methanol (30 ml) at room temperature, after which Raney nickel was slowly added and stirred for 12 hours in the presence of an attached hydrogen cylinder at the same temperature. The reaction mixture was filtered through a pad of celite to remove solids, after which the solvent was removed from the resulting filtrate under reduced pressure and the resulting product was used without further purification (1,200 g, 91.7%, white solid).

^1H NMR (400 MHz, CDCl ₃ ) δ 9.30 (d, J=1.7 Hz, 1H), 8.40 (dd, J=8.2, 2.2 Hz, 1H), 7.50 (d, J=8.2 Hz, 1H), 7.23 (t, J=8.0 Hz, 1H), 7.08 (s, 0.25H), 6.95 (s, 0.5H) , 6.82 (s, 0.25H), 6.73 ~ 6.68 (m, 2H), 6.62 ~ 6.61 (m, 1H), 5.02 (s, 2H), 3.78 (broad s, 2H), 1.55 (s, 6H); MSHP (ES) m/z 429.3 (M ⁺ +1).

Synthesis of compound 36, N-(3-(3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethyl- 2,4-dioxoimidazolidin-1-yl)phenyl)acetamide

1-(3-Aminophenyl)-3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-5,5-dimethylimidazolidin-2, 4-Dione (0.140 g, 0.327 mmol), acetic anhydride (0.031 ml, 0.327 mmol) and N,N-diisopropylethylamine (0.114 ml, 0.654 mmol) were dissolved in dichloromethane (10 ml) at room temperature, after which the resulting solution was stirred at at the same temperature for 18 hours. Water was poured into the reaction mixture and extraction was carried out with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-50%) and concentrated to give the title compound (0.110 g, 71.6%) as a foamy white solid.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.26 (dd, J=2.l, 0.7 Hz, 1H), 8.38 (dd, J=8.2, 2.2 Hz, 1H) , 8.22 (s, 1H), 7.68 (t, J=1.9 Hz, 1H), 7.50 (dd, J=8.2, 0.5 Hz, 1H), 7.25 ( t, J=8.0 Hz, 1H), 7.17 ~ 7.14 (m, 1H), 7.08 (s, 0.25H), 6.95 (s, 0.5H), 6.97 ~ 6.95 (m, 1H), 6.82 (s, 0.25H), 5.02 (s, 2H), 1.99 (s, 3H), 1.52 (s, 6H).

Synthesis of compound 37, 1-(1-acetylindolin-4-yl)-3-((5-(5-(difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)- 5,5-dimethylimidazolidine-2,4-dione

3-((5-(5-(Difluoromethyl)-1,3,4-oxadiazol-2-yl)pyridin-2-yl)methyl)-1-(indolin-4-yl)-5,5-dimethylimidazolidin- 2,4-Dione (0.100 g, 0.220 mmol), acetic anhydride (0.021 mL, 0.220 mmol) and N,N-diisopropylethylamine (0.077 mL, 0.440 mmol) were dissolved in dichloromethane (10 mL) at room temperature, and the resulting solution stirred at the same temperature for 18 hours. Water was poured into the reaction mixture and extraction was carried out with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dehydrated using anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting concentrate was purified by column chromatography (SiO ₂ , 12 g cartridge; ethyl acetate/hexane=0-50%) and concentrated to give the title compound (0.080 g, 73.2%) as a foamy white solid.

^1H NMR (400 MHz, CDCl ₃ ) δ 9.24 ~ 9.23 (m, 1H), 8.37 (dd, J=8.2, 2.2 Hz, 1H), 8.27 (d, J=8.1 Hz, 1H), 7.49 (dd, J=8.2, 0.6 Hz, 1H), 7.29 ~ 7.25 (m, 1H), 7.08 (s, 1H ), 6.95 (s, 1H), 6.92 (d, J=7.6 Hz, 1H), 6.82 (s, 1H), 5.00 (s, 2H), 4.14 ~ 4 .07 (m, 2H), 3.16 ~ 3.14 (m, 2H), 2.22 (s, 3H), 1.52 (s, 6H).

Protocol for measuring and analyzing the activity of a compound of the invention

<Experimental Example 1> Identification of inhibition of HDAC enzyme activity (in vitro)

Selective HDAC6 inhibitor is important for the selectivity of HDAC1 inhibition, which causes side effects, and accordingly, HDAC1/6 enzyme selectivity and cell selectivity (HDAC1: histone acetylation/HCAC6: tubulin acetylation) have been identified.

1. Experimental method

The HDAC enzyme inhibitory capacity of the test material was measured using a fluorescence-based drug assay kit (HDAC1 Fluorimetrie Drug Discovery Assay Kit (Enzolifesciences: BML-AK511) and recombinant human HDAC6 (Calbiochem: 382180). For the HDAC1 assay, samples were treated at a concentration of 100. 1000 and 10000 nM. For HDAC6 analysis, samples were treated at concentrations of 0.1, 1, 10, 100 and 1000 nM. After the above sample treatment, the reaction was continued at 37°C for 60 min, treated with developer and reacted at 37°C in for 30 min, after which the fluorescence intensity was measured (Ex 390, Em 460) using FlexStatin3 (Molecular Device).

2. Experimental results

The results of the search for inhibition of HDAC enzyme activity obtained in accordance with the above experimental method are shown in Table 2.

Referring to Table 2, it can be confirmed that the 1,3,4-oxadiazole derivative compounds of the present invention exhibit excellent selectivity towards the HDAC1/6 enzyme.

Claims (50)

1. The compound represented by the following chemical formula I, or pharmaceutically acceptable salts thereof: [Chemical formula I] Where each of Z ₁ -Z ₄ independently represents N or CR ₀ where R ₀ is H or halogen; R ₁ represents CX ₃ or CX ₂ H, where X is halogen; is or Where represents each of R ₄ and R ₅ independently represents H or C1-C4 alkyl, Where is yourself R ₄ and R ₅ are each independently C1-C4 alkyl, Z ₅ represents NR ₆ or CH ₂ , R ₆ represents C1-C4 alkyl, -C(=O)-(C1-C4 alkyl), -C(=O)-O-(C1-C4 alkyl) or 4-6 membered heterocycloalkyl having one O; L ₁ represents -(C1-C2 alkylene)-; is a C6-C12 aryl, 5-9 membered heteroaryl having at least one N, or ; each of R ₂ and R ₃ independently represents H, halogen, C6-C12 aryl, 5- or 6-membered heteroaryl having N or O, 5- or 6-membered heterocycloalkyl having N, 5- or 6-membered heterocycloalkenyl having N, -C(=O)-O-(C1-C4 alkyl), -C(=O)-(C1-C4 alkyl), -NH-C(=O)-(C1-C4 alkyl), -NO ₂ or -NH ₂ , at least one H of the above R ₂ and R ₃ may in each case be independently substituted with halogen or C1-C4 alkyl; And n and m are in each case independently equal to 1 or 2. 2. The compound represented by chemical formula I, or its pharmaceutically acceptable salts according to claim 1, where each of Z ₁ and Z ₂ independently represents N, CH or CF, and each of Z ₃ and Z ₄ represents CH; _R1 , , R ₄ -R ₆ , Z ₅ , L ₁ , n and m are the same as in chemical formula I, paragraph 1; And R ₂ and R ₃ are each independently H, halogen, halogenated or unsubstituted phenyl, furanyl, pyridinyl, C1-C4 alkyl substituted or unsubstituted piperidinyl, C1-C4 alkyl substituted or unsubstituted tetrahydropyridinyl, -C(=O)-O-(C1 -C4 alkyl), -C(=O)-(C1-C4 alkyl), -NH-C(=O)-(C1-C4 alkyl), -NO ₂ or -NH ₂ . 3. The compound represented by chemical formula I, or its pharmaceutically acceptable salts according to claim 1, where each of Z ₁ and Z ₂ independently represents N, CH or CF, and each of Z ₃ and Z ₄ represents CH; Z ₅ , R ₁ , R ₄ -R ₆ , L1, n and m are the same as in chemical formula I according to claim 1; is phenyl, indole or And R ₂ and R ₃ are each independently H, halogen, halogenated or unsubstituted phenyl, furanyl, pyridinyl, C ₁ -C ₄ alkyl substituted or unsubstituted piperidinyl, C 1 -C 4 alkyl substituted or unsubstituted tetrahydropyridinyl, -C(=O)-O -(C1-C4 alkyl), -C(=O)-(C1-C4 alkyl), -NH-C(=O)-(C1-C4 alkyl), -NO ₂ or -NH ₂ . 4. The compound represented by chemical formula I, or its pharmaceutically acceptable salts according to claim 1, where the compound represented by chemical formula 1 is a compound selected from the group consisting of the following compounds 1-37: 5. Pharmaceutical composition containing a compound represented by chemical formula I according to any one of paragraphs. 1-4, or pharmaceutically acceptable salts thereof, as an effective ingredient for the prevention or treatment of histone deacetylase (HDAC)-mediated diseases. 6. The pharmaceutical composition according to claim 5, where diseases mediated by histone deacetylase include infectious diseases, neoplasms, endocrinopathy, nutritional and metabolic diseases, mental and behavioral disorders, neurological diseases, ocular and ocular adnexal diseases, diseases of the circulatory system, respiratory diseases, diseases digestive organs, diseases of the skin and subcutaneous tissue, diseases of the musculoskeletal system and connective tissue or teratosis, deformations and chromosomal aberration. 7. Pharmaceutical composition according to claim 6, where endocrinopathy, nutritional and metabolic diseases are Wilson's disease, amyloidosis or diabetes; mental and behavioral disorders represent depression or Rett syndrome; neurological diseases are central nervous system atrophy, neurodegenerative disease, movement disorder, neuropathy, motor neuron disease, or demyelinating disease of the central nervous system; ocular and ocular adnexal diseases represent uveitis; diseases of the skin and subcutaneous tissue are psoriasis; diseases of the musculoskeletal system and connective tissue are rheumatoid arthritis, osteoarthritis or systemic lupus erythematosus; teratosis, deformities and chromosomal aberration represent autosomal dominant polycystic kidney disease; infectious diseases are prion disease; the neoplasm is a benign tumor or a malignant tumor; diseases of the circulatory system represent atrial fibrillation or stroke; respiratory diseases represent asthma; And Digestive diseases include alcoholic liver disease, inflammatory bowel disease, Crohn's disease or peptic ulcer. 8. A method for preventing or treating diseases mediated by histone deacetylase (HDAC), comprising administering a therapeutically effective amount of a compound represented by chemical formula I according to any one of claims. 1-4, or pharmaceutically acceptable salts thereof; or a pharmaceutical composition containing them as an effective ingredient to a subject in need thereof. 9. The use of a compound represented by chemical formula I according to any one of paragraphs. 1-4, or pharmaceutically acceptable salts thereof; or a pharmaceutical composition containing them as an effective ingredient for the prevention or treatment of histone deacetylase (HDAC)-mediated diseases. 10. The use of a compound represented by chemical formula I according to any one of paragraphs. 1-4, or pharmaceutically acceptable salts thereof; or a pharmaceutical composition containing them as an effective ingredient for the preparation of a medicament for the prevention or treatment of histone deacetylase (HDAC)-mediated diseases.