CN119816495A - 1,3,4-oxadiazole derivatives as histone deacetylase 6 inhibitors and their uses - Google Patents

Abstract

The present invention relates to a novel compound having histone deacetylase 6 (HDAC6) inhibitory activity, a preparation method thereof and a use thereof. The novel compound of the present invention, its stereoisomer or a pharmaceutically acceptable salt thereof has HDAC6 inhibitory activity and is effectively used to prevent or treat HDAC6-related diseases, including cancer, inflammatory diseases, autoimmune diseases, nervous system diseases or neurodegenerative diseases.

Description

1,3, 4-Oxadiazole derivative compounds as histone deacetylase 6 inhibitors and uses thereof

Technical Field

The invention relates to a novel 1,3, 4-oxadiazole derivative compound with histone deacetylase 6 (HDAC 6) inhibitory activity, a preparation method and application thereof.

Background

Post-translational modifications (e.g., acetylation) in cells are very important regulatory modules in biological process centers, under the strict control of multiple enzymes. Histones are core proteins that constitute chromatin, which act as axes of DNA entanglement, helping DNA aggregation. Furthermore, the balance between acetylation and deacetylation of histones plays a crucial role in gene expression.

Histone Deacetylases (HDACs) are enzymes that remove acetyl groups of lysine residues constituting chromatin, which are known to be involved in gene silencing, and induce cell cycle arrest, angiogenesis inhibition, immunomodulation, cell death, and the like (Hassig et al, curr. Opin. Chem. Biol.1997,1, 300-308). Furthermore, inhibition of HDAC enzymatic function has been reported to reduce the activity of cancer cell survival-related factors in vivo and activate cancer cell death-related factors, thereby inducing self-death of cancer cells (Warrell et al, j. Natl. Cancer Inst.1998,90, 1621-1625).

There are 18 HDACs known in humans, and they can be classified into four classes according to homology with yeast HDACs. Of these, 11 HDACs with zinc as cofactor can be classified into 3 groups, class I (HDACs 1,2, 3 and 8), class II (IIa: HDACs 4, 5, 7 and 9; IIb: HDACs 6 and 10) and class IV (HDACs 11). In addition, 7 HDACs of class III (SIRT 1-7) use NAD+ as a cofactor instead of zinc (Bolden et al, nat. Rev. Drug discovery 2006,5 (9), 769-784).

Although various HDAC inhibitors are still in preclinical or clinical development, only non-selective HDAC inhibitors have been known to date as anticancer agents, with vorinostat (SAHA) and romidepsin (FK 228) having been approved for the treatment of cutaneous T cell lymphomas and panobinostat (LBH-589) having been approved for the treatment of multiple myeloma. However, non-selective HDAC inhibitors are generally known to cause side effects such as fatigue, nausea, etc. at high doses (Piekarz et al, pharmaceuticals 2010,3,2751-2767). These side effects are reported to be caused by inhibition of class I HDAC, and non-selective HDAC inhibitors are limited in drug development in fields other than anticancer drugs due to these side effects (Witt et al, CANCER LETTERS 277, (2009), 8-21).

Meanwhile, it has been reported that selective class II HDAC inhibition may not produce the toxicity exhibited by class I HDAC inhibition, and that the development of selective HDAC inhibitors may address side effects such as toxicity caused by non-selective HDAC inhibition. Therefore, selective HDAC inhibitors are expected to be developed as effective treatments for a variety of diseases (Matthias et al, mol. Cell. Biol.2008,28, 1688-1701).

HDAC6 is one of the class IIb HDACs, which are known to be primarily present in the cytoplasm, and are involved in the deacetylation of a variety of non-histone substrates (HSP 90, coractin, etc.) including tubulin (Yao et al, mol. Cell 2005,18,601-607). HDAC6 may have two catalytic domains and the C-terminal zinc finger domain may bind to ubiquitinated proteins. Since HDAC6 has a variety of nonhistones as substrates, it is known to play an important role in a variety of diseases such as cancer, inflammatory diseases, autoimmune diseases, neurological diseases, neurodegenerative diseases, etc. (Santo et al, blood 2012 119,2579-2589; vishwakara et al, international Immunopharmacology 2013,16,72-78; hu et al, J.Neurol. Sci.2011,304, 1-8).

The common structural feature of the classes of HDAC inhibitors is composed of a cap group, a linker group, and a Zinc Binding Group (ZBG), as shown by the following vorinostat structure. There have been many researchers studying the inhibitory activity and selectivity of enzymes by structural modification of cap groups and linker groups. Zinc binding groups are known to play a more important role in the inhibitory activity and selectivity of enzymes (Wiest et al, j. Org. Chem. 2013:5051-5065; method et al, bioorg. Med. Chem. Lett.2008,18, 973-978).

Most zinc binding groups are hydroxamic acids or benzamides, wherein hydroxamic acid derivatives exhibit strong HDAC inhibitory effects, but suffer from problems such as low bioavailability and severe off-target activity. Benzamide contains aniline and thus has a problem of generating toxic metabolites in vivo (Woster et al, med. Chem. Commun.2015, online publication).

Therefore, in order to treat cancer, inflammatory diseases, autoimmune diseases, nervous system diseases, neurodegenerative diseases, etc., it is required to develop a selective HDAC6 inhibitor having a zinc binding group, which has no side effects, and has improved bioavailability unlike a non-selective inhibitor having side effects.

Prior art literature

WO 2011/091213:ACY-1215

WO 2011/01186 Tubastatin (Tubastatin)

WO 2013/052110:Sloan-K

WO 2013/041407:Cellzome

WO 2013/134467:Kozi

WO 2013/008162:Novartis

WO 2013/080120:Novartis

WO 2013/066835:Tempero

WO 2013/066838:Tempero

WO 2013/066833:Tempero

WO 2013/066839:Tempero

Disclosure of Invention

Technical problem

An object of the present invention is to provide a compound having selective histone deacetylase 6 (HDAC 6) inhibitory activity, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof.

It is another object of the present invention to provide a pharmaceutical composition comprising a compound having selective HDAC6 inhibitory activity, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof.

It is another object of the present invention to provide a method for preparing the same.

It is another object of the present invention to provide a pharmaceutical composition for preventing or treating a disease associated with HDAC6 activity.

It is another object of the present invention to provide its use in the manufacture of a medicament for the prevention or treatment of a disease associated with HDAC6 activity.

It is another object of the present invention to provide a method for preventing or treating a disease associated with HDAC6 activity, comprising administering a therapeutically effective amount of a compound as described above.

It is another object of the present invention to provide a use for preventing or treating a disease associated with HDAC6 activity.

Solution to the problem

The present inventors have found an oxadiazole derivative compound having histone deacetylase 6 (HDAC 6) inhibitory activity and have completed the present invention by using the oxadiazole derivative compound to inhibit or treat diseases associated with HDAC6 activity.

The following will explain in detail. All combinations of the various elements disclosed herein are within the scope of the invention. Furthermore, the scope of the present invention is not limited by the following detailed description.

1,3, 4-Oxadiazole derivative compounds

In one general aspect, the present invention provides a1, 3, 4-oxadiazole derivative compound represented by the following formula I:

[ formula I ]

In the above formula I of the present invention,

R ₁ is-C _1-4 haloalkyl;

x ₁ to X ₄ are each independently CR _X or N;

R _X is-H, -C _1-4 alkyl, -C _1-4 haloalkyl or-halogen;

y is CR _Y or N;

r _Y is-H or-C _1-4 alkyl;

Z is NR _Z, O or S;

R _Z is-H or-C _1-4 alkyl;

W is O or S;

m is 0 or 1;

Ring V is aryl, heteroaryl or hydroheteroaryl (hydroheteroaryl) { wherein at least one H of the aryl, heteroaryl or hydroheteroaryl ring may be substituted by-C _1-4 alkyl, -C _1-4 aminoalkyl, -C _1-4 hydroxyalkyl, -C _1-4 haloalkyl, -halogen, - (CH ₂) n-cycloalkyl, - (CH ₂) n-heterocyclyl or- (CH ₂) n-heteroaryl [ wherein at least one H of the- (CH ₂) n-cycloalkyl, - (CH ₂) n-heterocyclyl or- (CH ₂) n-heteroaryl ring may be substituted by-C _1-4 alkyl, -C _1-4 haloalkyl, -halogen, cycloalkyl or heterocyclyl (wherein at least one H of the cycloalkyl or heterocyclyl ring may be substituted by-C _1-4 alkyl) ]}; and

N is 0,1 or 2.

According to one embodiment of the present invention, the compound represented by formula I may be within the following range:

R ₁ is-C _1-4 haloalkyl;

X ₁ is N;

Each of X ₂ to X ₄ is independently CR _X;

r _X is-H or-halogen;

y is CR _Y or N;

r _Y is-H

Z is NR _Z, O or S;

R _Z is-C _1-4 alkyl;

W is O or S;

m is 0 or 1;

Ring V is aryl, heteroaryl or hydroheteroaryl { wherein at least one H on the aryl, heteroaryl or hydroheteroaryl ring may be substituted by-C _1-4 alkyl, -C _1-4 aminoalkyl, -halogen, - (CH ₂) n-cycloalkyl, - (CH ₂) n-heterocyclyl or- (CH ₂) n-heteroaryl } - [ wherein at least one H on the- (CH ₂) n-cycloalkyl, - (CH ₂) n-heterocyclyl or- (CH ₂) n-heteroaryl ring may be substituted by-C _1-4 alkyl, -halogen, cycloalkyl or heterocyclyl (wherein at least one H on the cycloalkyl or heterocyclyl ring may be substituted by-C _1-4 alkyl) ] }; and

N is 0 or 1.

Furthermore, according to an embodiment of the present invention, the compound represented by formula I may be within the following range:

R ₁ is-CF ₂ H or-CF ₃.

Furthermore, according to an embodiment of the present invention, the compound represented by formula I may be within the following range:

x ₁ is N, and

X ₂ to X ₄ are each independently CH or CF.

Furthermore, according to an embodiment of the present invention, the compound represented by formula I may be within the following range:

y is CH or N;

Z is N-C _1-4 alkyl, O or S;

W is O or S, and

M is 0 or 1.

Furthermore, according to an embodiment of the present invention, the compound represented by formula I may be within the following range:

Ring V is phenyl, 5-10 membered heteroaryl or 9-10 membered hydrogen heteroaryl { wherein at least one H of the phenyl, 5-10 membered heteroaryl or 9-10 membered hydrogen heteroaryl ring may be substituted by-C _1-4 alkyl, -C _1-4 aminoalkyl, -halogen, - (CH ₂) n-cycloalkyl, - (CH ₂) n-heterocyclyl or- (CH ₂) n-heteroaryl } - [ wherein at least one H of the- (CH ₂) n-cycloalkyl, - (CH ₂) n-heterocyclyl or- (CH ₂) n-heteroaryl ring may be substituted by-C _1-4 alkyl, -halogen, 4-6 membered cycloalkyl or 4-6 membered heterocyclyl (wherein at least one H of the 4-6 membered cycloalkyl or 4-6 membered heterocyclyl ring may be substituted by-C _1-4 alkyl) ] }, and

N is 0 or 1.

Furthermore, according to one embodiment of the present invention, specific compounds represented by formula I of the present invention are shown in table 1 below:

TABLE 1

In the present invention, the term "alkyl" as used herein may refer to a straight or branched acyclic, cyclic or saturated hydrocarbon wherein the carbon atoms are attached, unless otherwise indicated. For example, "C _1-4 alkyl" may refer to an alkyl group containing 1 to 4 carbon atoms. The acyclic alkyl group may include, for example, methyl, ethyl, n-propyl, n-butyl, isopropyl, sec-butyl, isobutyl, tert-butyl, and the like, but is not limited thereto. The cyclic alkyl group may be used interchangeably with "cycloalkyl" in this specification and may include, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and the like, but is not limited thereto.

In the present invention, "alkoxy" may refer to- (O-alkyl) as the alkyl ether group, wherein alkyl is as defined above. For example, "C _1-4 alkoxy" may refer to an alkoxy group containing a C _1-4 alkyl group, i.e., - (O-C _1-4 alkyl), examples of which may include, but are not limited to, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, and the like.

In the present invention, "halogen" may be F, cl, br or I.

In the present invention, the term "haloalkyl" may denote a straight-chain or branched alkyl (hydrocarbon) having a carbon atom substituted with at least one halogen as defined herein. Examples of haloalkyl include, but are not limited to, methyl, ethyl, propyl, isopropyl, isobutyl, or n-butyl independently substituted with at least one halogen (e.g., F, cl, br, or I).

In the present invention, the term "hydroxyalkyl" may refer to a straight or branched alkyl (hydrocarbon) group having a carbon atom substituted with-OH. Examples of hydroxyalkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, isobutyl, or n-butyl independently substituted with at least one hydroxyl group.

In the present invention, the term "aminoalkyl" may refer to a straight or branched alkyl (hydrocarbon) group having a carbon atom substituted with an amino group- (NR' R "). Herein, R 'and R "may each be independently selected from hydrogen and C _1-4 alkyl, and the selected R' and R" may each be independently substituted or unsubstituted.

In the present invention, the term "heterocyclyl" may refer to a ring containing 1 to 5 heteroatoms selected from N, O and S as ring-forming atoms, which may be saturated or partially unsaturated. When heterocyclyl is unsaturated, it may be referred to herein as a heterocycle. Unless otherwise indicated, a heterocyclyl may be a single ring or multiple rings, such as spiro rings, bridged rings, or fused rings. In addition, "3 to 12 membered heterocyclic group" may refer to a heterocyclic group containing 3 to 12 ring members. Examples of heterocyclyl groups may include, but are not limited to, pyrrolidine, piperidine, imidazolidine, pyrazolidine, butyrolactam, valerolactam, imidazolidinone, hydantoin, dioxolane, phthalimide, piperidine, pyrimidine-24 (1H, 3H) -dione, 1, 4-dioxane, morpholine, thiomorpholine-S-oxide, thiomorpholine-S, S-oxide, piperazine, pyran, pyridone, 3-pyrroline, thiopyran, pyridone, tetrahydrofuran, tetrahydrothiophene, quinuclidine, tropane, 2-azaspiro [3.3] heptane, (1R, 5S) -3-azabicyclo [3.2.1] octane, (1S, 4S) -2-azabicyclo [2.2.2] octane, or (1R, 4R) -2-oxa-5-azabicyclo [2.2.2] octane, and the like.

In the present invention, "aromatic hydrocarbon" means an aromatic hydrocarbon ring. The aromatic hydrocarbon may be a monocyclic aromatic hydrocarbon or a polycyclic aromatic hydrocarbon. The number of ring carbon atoms in the aromatic hydrocarbon may be 5 or more to 30 or less, 5 or more to 20 or less, or 5 or more to 15 or less. Examples of aromatic hydrocarbons may include, but are not limited to, benzene, naphthalene, fluorene, anthracene, phenanthrene, biphenyl terphenyl, tetrabiphenyl, pentabiphenyl, hexabiphenyl, triphenylene, pyrene, benzofluoranthene, and,Etc. In this specification, a moiety obtained by removing one hydrogen atom from the above-mentioned "aromatic hydrocarbon" is referred to as "aryl".

In the present invention, "heteroarene" may refer to a ring containing one or more of O, N, P, si and S as heteroatoms. The number of ring carbon atoms of the heteroarene may be 2 or more to 30 or less, or 2 or more to 20 or less. The heteroaromatics may be monocyclic heteroaromatics or polycyclic heteroaromatics. Polycyclic heteroarenes may have, for example, a bicyclic structure or a tricyclic structure. Examples of heteroarenes include, but are not limited to, thiophenes, purines, pyrroles, pyrazoles, imidazoles, thiazoles, oxazoles, isothiazoles, oxadiazoles, triazoles, pyridines, bipyridines, triazines, acridines, pyridazines, pyrazines, quinolines, quinazolines, quinoxalines, phenoxazines, phthalazines, pyrimidines, pyridopyrimidines, pyridopyrazines, isoquinolines, indoles, carbazoles, imidazopyridazines, imidazopyridines, imidazopyrimidines, pyrazolopyrimidines, imidazopyrazines, or pyrazolopyridines, N-arylcarbazole, N-heteroarylcarbazole, N-alkyl carbazole, benzoxazole, benzimidazole, benzothiazole, benzothiophene, benzofuran, phenanthroline, isoxazole, oxadiazole, thiadiazole, benzothiazole, tetrazole, phenothiazine, dibenzothiophene, dibenzofuran, and the like. In one embodiment of the present invention, the heteroarenes may also include bicyclic heterocyclic arenes, including arenes fused to heterocyclyl rings or heteroarenes fused to cycloalkyl rings. In the present specification, a moiety obtained by removing one hydrogen atom from the above-mentioned "heteroarene" is referred to as "heteroaryl".

The compounds of formula I of the present invention may contain at least one asymmetric carbon and thus may exist as racemates, racemic mixtures, single enantiomers, diastereomeric mixtures and individual diastereomers. These stereoisomers may be isolated by conventional techniques, for example, the compounds represented by formula I may be isolated by column chromatography, HPLC, and the like. In addition, each stereoisomer of the compound represented by formula I may be stereospecifically synthesized using optically pure starting materials and/or reagents of known configuration.

In the present invention, the term "enantiomer" as used herein refers to a compound having the same chemical formula or molecular formula but different spatial arrangement or a salt thereof. Each of these enantiomers and mixtures thereof are also included within the scope of the present invention. Unless otherwise indicated, the solid bond (-) attached to an asymmetric carbon atom may include a wedge-shaped solid bond representing an absolute arrangement of the stereocentersOr wedge-shaped dotted bond

The compounds of formula I of the present invention may exist in the form of "pharmaceutically acceptable salts". As salts, acid addition salts formed from pharmaceutically acceptable free acids may be used. The term "pharmaceutically acceptable salt" as used herein refers to a concentrate having a relatively non-toxic and harmless effective effect on a patient, including any organic or inorganic acid addition salts of the compounds of formula I, wherein the side effects caused by these salts do not reduce the beneficial efficacy of the compound.

Acid addition salts are prepared by conventional methods, for example, by dissolving the compound in an excess of aqueous acid and precipitating the salt with a water miscible organic solvent such as methanol, ethanol, acetone or acetonitrile. Equimolar amounts of the compound and the acid or alcohol are dissolved in water and heated, and the mixture may then be evaporated to dryness or the salt which has been separated off may be suction filtered.

In this case, as the free acid, an organic acid and an inorganic acid may be used, wherein the inorganic acid may include hydrochloric acid, phosphoric acid, sulfuric acid, nitric acid, and the like, and the organic acid may include methanesulfonic acid, p-toluenesulfonic acid, acetic acid, trifluoroacetic acid, maleic acid, succinic acid, oxalic acid, benzoic acid, tartaric acid, fumaric acid, mandelic acid, propionic acid, citric 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, and the like. But the organic acid and the inorganic acid are not limited thereto.

In addition, a pharmaceutically acceptable metal salt can also be prepared using a base. The alkali metal salt or alkaline earth metal salt is obtained, for example, by dissolving the compound in an excess alkali metal hydroxide or alkaline earth metal hydroxide solution, filtering the insoluble compound salt, and then evaporating and drying the filtrate. Here, as the metal salt, sodium salt, potassium salt or calcium salt is particularly suitable in terms of pharmacy, but the metal salt is not limited thereto. Furthermore, the corresponding silver salts may be obtained by reacting an alkali metal or alkaline earth metal salt with a suitable silver salt (e.g. silver nitrate).

Pharmaceutically acceptable salts of the present invention include salts of acidic or basic groups that may be present in the compounds of formula I described above, unless otherwise indicated. For example, pharmaceutically acceptable salts may include sodium, calcium, potassium salts of hydroxyl groups, other pharmaceutically acceptable salts of amino groups may include hydrobromide, sulfate, bisulfate, phosphate, hydrogen phosphate, dihydrogen phosphate, acetate, succinate, citrate, tartrate, lactate, mandelate, methanesulfonate (methanesulfonate) (methanesulfonate), p-toluenesulfonate (p-toluenesulfonate) (tosylate), and the like, which may be prepared by salt preparation methods known in the art.

Process for preparing 1,3, 4-oxadiazole derivative compounds

The present invention provides a process for preparing a1, 3, 4-oxadiazole derivative compound represented by the following chemical formula I:

[ formula I ]

Formula I is as defined above.

In the present invention, preferred methods for preparing the oxadiazole derivative compound represented by formula I, its stereoisomers or pharmaceutically acceptable salts thereof are shown in the following [ schemes 1] to [ scheme 8], which also include modified preparation methods obvious to those skilled in the art.

Reaction scheme 1

According to the above reaction scheme 1, hydrazine is added to the compound 1-1 to prepare the compound 1-2, which is then reacted with trifluoroacetic anhydride or difluoroacetic anhydride to prepare the compound 1-3, which is then subjected to a bromination reaction to synthesize the compound 1-4. Compounds 1-4 are Zn-binding moieties of HDAC 6 inhibitors, useful as intermediates in the synthesis of all compounds.

Reaction scheme 2

Compound 2-2 was prepared from compound 2-1 using hydrazine according to reaction scheme 2 above, followed by 1,3, 4-oxadiazol-2 (3H) -thione compound 2-4 using CDI using 1,3, 4-oxadiazol-2 (3H) -one and potassium ethyl xanthate. In addition, compound 2-3 may be prepared by adding Lawesson's reagent to compound 2-2, and then 1,3, 4-thiadiazol-2 (3H) -one compound 2-4 may be prepared by using CDI. Compounds 2-5 were prepared by substitution reaction of compounds 2-4 with compounds 1-4. Examples of the compounds 2 to 5 prepared by the above reaction scheme 2 may include compound numbers 1, 5, 15, 16, 17, 18, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 59, 60, 61, 62, and the like.

Reaction scheme 3

In reaction scheme 3, compound 3-1 having an aldehyde structure is subjected to a reductive amination reaction to prepare compound 3-2, then compound 3-3 is prepared using hydrazine, and then 1,3, 4-oxadiazol-2 (3H) -one compound 3-4 is prepared using CDI. Compounds 3-5 may then be prepared by substitution reactions with compounds 1-4. Examples of the compounds 3 to 5 prepared by the above reaction scheme 3 may include compound numbers 2, 4, etc.

[ Reaction scheme 3-1]

In reaction scheme 3-1, a dioxolane compound 3-1-1 protecting the aldehyde structure is prepared from compound 3-1 using ethylene glycol, and then compound 3-1-2 is prepared using hydrazine. Then, 1,3, 4-oxadiazol-2 (3H) -thione compound 3-1-3 was prepared using CDI using 1,3, 4-oxadiazol-2 (3H) -one and potassium ethyl xanthate. Then, the compound 3-1-4 was prepared by substitution reaction with the compound 1-4, and the compound 3-1-5 was prepared by removing the aldehyde protecting group dioxolane using iron (III) chloride hexahydrate. Compounds 3-5 may then be prepared by reductive amination. Examples of the compound 3-5 prepared by the reaction scheme 3-1 may include the compound number 84、85、86、87、88、89、90、91、92、93、94、95、96、97、98、99、107、108、109、110、111、112、113、114、117、118、119、120、121、122、123、124、125、128、129、130、131、132、133、134 and the like.

[ Reaction scheme 3-2]

In reaction scheme 3-2, compound 3-1 having an aldehyde structure is subjected to a reductive amination reaction to prepare compound 3-2-1, then compound 3-2-2 is prepared using hydrazine, and then 1,3, 4-oxadiazol-2 (3H) -thione compound 3-2-4 is prepared with CDI by using 1,3, 4-oxadiazol-2 (3H) -one and potassium ethyl xanthate. In addition, compound 3-2-3 was prepared by adding Lawesson's reagent to compound 3-2-2, and then 1,3, 4-thiadiazol-2 (3H) -one compound 3-2-4 was prepared by using CDI. Then, compound 3-2-5 is prepared by using the substitution reaction of compound 3-2-4 with compound 1-4, compound 3-2-6 is prepared by removing the amine protecting group, and then compound 3-2-7 is prepared by performing the reductive amination reaction. Examples of the compounds 3-2-7 prepared by the above reaction scheme 3-2 may include compound numbers 63, 64, 65, 66, 67, 68, 77, 78, 79, 83, and the like.

Reaction scheme 4

In reaction scheme 4, an ester compound 4-1 having a halogen element is subjected to a C-C coupling (Suzuki coupling) reaction to prepare a compound 4-2, and then subjected to a reduction reaction to prepare a compound 4-3. In addition, compound 4-3 was prepared from compound 4-1 by C-N coupling (Buchwald reaction) and substitution reaction. Then, compound 4-4 was prepared using hydrazine, and then 1,3, 4-oxadiazol-2 (3H) -thione compound 4-6 was prepared with CDI by using 1,3, 4-oxadiazol-2 (3H) -one and potassium ethylxanthate. In addition, compound 4-5 was prepared by adding Lawesson's reagent to compound 4-4, and then 1,3, 4-thiadiazol-2 (3H) -one compound 4-6 was prepared by using CDI. Subsequently, compounds 4 to 7 were prepared by substitution reaction with compounds 1 to 4, and then compounds 4 to 8 were prepared by removing the amine-based protecting group. Examples of compounds 4-8 may include compound numbers 20, 23, 36, etc. Compounds 4-9 were then prepared by reductive amination. Examples of the compounds 4 to 9 prepared by the above reaction scheme 4 may include compound number 8、9、10、21、22、24、25、26、29、30、37、38、39、40、41、55、56、57、58、75、76、80、81、82、100、101、102、103、104、105、106、115、116、126、127 and the like.

In addition, compound 4-10 may be prepared by subjecting compound 4-8 prepared according to reaction scheme 4 to a reductive amination reaction, compound 4-11 may be prepared by removing an amine protecting group, and then compound 4-12 may be prepared by a reductive amination reaction. Examples of compounds 4-12 may include compound numbers 27, 28, etc.

[ Reaction scheme 4-1]

In reaction scheme 4-1, compound 4-2 is prepared from ester compound 4-1 having a halogen element using hydrazine, and 1,3, 4-oxadiazol-2 (3H) -one compound 4-3 is prepared using CDI. Then, compounds 4 to 4 were prepared by substitution reaction with compounds 1 to 4, followed by amine substitution reaction to prepare compounds 4 to 9. Examples of the compounds prepared by the above reaction scheme 4-1 may include compound numbers 6,7, etc.

Reaction scheme 5

In reaction scheme 5, an amine-containing compound 5-1 is subjected to an amine protecting group and alkylation reaction to prepare compound 5-2, then hydrazine is used to prepare compound 5-3, and then 1,3, 4-oxadiazol-2 (3H) -thione compound 5-4 is prepared with CDI using 1,3, 4-oxadiazol-2 (3H) -one and potassium ethyl xanthate. Compounds 5-5 are then prepared by substitution reactions with compounds 1-4. Examples of the compounds 5 to 5 prepared by the reaction scheme 5 may include compound numbers 19, 31, 32, and the like.

In addition, compounds 5-6 may be prepared by removing amine protecting groups of compounds 5-5 prepared according to reaction scheme 5, and examples of compounds 5-6 may include compound numbers 3, 11, 33, 34, 35, and the like.

Compounds 5-7 were then prepared by reductive amination. Examples of the compounds 5 to 7 prepared by the above reaction scheme 5 may include compound numbers 12, 13, 14, 135, 136, 137, 138, 139, 140, 141, and the like.

Reaction scheme 6

In reaction scheme 6, acetate compound 6-2 is prepared from bromine compound 6-1 through a substitution reaction, then hydrazine carboxylate compound 6-3 is prepared by performing a substitution reaction, and then 1,3, 4-oxadiazin-2-one compound 6-4 is prepared by using sodium ethoxide. Compounds 6-5 are then prepared by substitution reactions with compounds 1-4. Examples of the compounds 6 to 5 prepared by the above reaction scheme 6 may include compound numbers 69, 70, 71, 72, 73, 74, and the like.

Reaction scheme 7

In reaction scheme 7, compound 7-1 is protected with an amine protecting group to prepare compound 7-2, then a triple bond compound 7-4 is prepared by substitution reaction with compound 7-3, and then an oxazol-2 (3H) -one compound 7-5 is prepared using bis (trifluoromethanesulfonyl) imide silver. Subsequently, compound 7-6 can be prepared using hydrazine, followed by reaction with trifluoroacetic anhydride or difluoroacetic anhydride to prepare compound 7-7. Examples of the compound prepared by reaction scheme 7 may include compound numbers 142, 143, and the like.

Reaction scheme 8

In scheme 8, compound 8-2 can be prepared by the substitution reaction of imidazol-2-one compound 8-1 with compound 1-4. Examples of the compound produced by reaction scheme 8 include compound number 144 and the like.

Use of 1,3, 4-oxadiazole derivative compounds

The present invention provides the use of a compound represented by the following formula I:

[ formula I ]

Formula I is as defined above.

According to one embodiment of the present invention, there is provided a pharmaceutical composition comprising a compound represented by formula I, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof as an active ingredient.

Further, according to an embodiment of the present invention, there is provided a pharmaceutical composition for preventing or treating diseases associated with histone deacetylase 6 activity, which comprises the compound represented by the above formula I, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof, as an active ingredient. The pharmaceutical composition of the present invention selectively inhibits histone deacetylase 6, thereby exhibiting a remarkable effect in preventing or treating diseases associated with histone deacetylase 6 activity.

Diseases associated with histone deacetylase 6 (HDAC 6) activity include cancer, inflammatory diseases, autoimmune diseases, neurological diseases, or neurodegenerative diseases, including in particular lung cancer, colon cancer, breast cancer, prostate cancer, liver cancer, brain cancer, ovarian cancer, stomach cancer, skin cancer, pancreatic cancer, glioma, neuroblastoma, leukemia, lymphoma, multiple myeloma, solid cancer, wilson's disease, spinocerebellar ataxia, prion disease, parkinson's disease, huntington's disease, amyotrophic lateral sclerosis, amyloidosis, alzheimer's disease, alcoholic liver disease, spinal muscular atrophy, rheumatoid arthritis, or osteoarthritis, and symptoms or diseases associated with dysfunctions of histone deacetylase.

Examples of histone deacetylase mediated diseases according to an embodiment of the present invention may include infectious diseases, tumors, endocrine, nutritional and metabolic diseases, mental and behavioral disorders, nervous system diseases, eye and eye attachment diseases, circulatory system diseases, respiratory system diseases, digestive system diseases, skin and subcutaneous tissue diseases, musculoskeletal and connective tissue diseases, or congenital malformations, variations and chromosomal abnormalities. In addition, histone deacetylase mediated diseases include symptoms or diseases related to dysfunctions of histone deacetylase 6.

In the present invention, the infectious disease may be prion disease. Furthermore, the tumor may be a benign tumor (e.g., myelodysplastic syndrome) or a malignant tumor (e.g., multiple myeloma, lymphoma, leukemia, lung cancer, colorectal cancer, colon cancer, prostate cancer, urothelial cell cancer, breast cancer, melanoma, skin cancer, liver cancer, brain cancer, stomach cancer, ovarian cancer, pancreatic cancer, head and neck cancer, oral cancer, or glioma). Furthermore, endocrine, nutritional and metabolic diseases may be wilson's disease, amyloidosis or diabetes. Furthermore, the mental and behavioral disorder may be depression or rett syndrome. In addition, the neurological disease may include central nervous system atrophy (e.g., huntington's disease, spinal Muscular Atrophy (SMA), spinocerebellar ataxia (SCA)), neurodegenerative disease (e.g., alzheimer's disease), movement disorders (e.g., parkinson's disease), neuropathies (e.g., hereditary neuropathy (shac-mary-fig disease), sporadic neuropathy, inflammatory neuropathy, pharmaceutical neuropathy), motor neuron disease (e.g., amyotrophic Lateral Sclerosis (ALS)), or central nervous system demyelinating disease (e.g., multiple Sclerosis (MS)). In addition, the eye and eye attachment disease may be uveitis. Furthermore, the circulatory disease may be atrial fibrillation or stroke. Furthermore, the respiratory disease may be asthma. Furthermore, the digestive system disease may be alcoholic liver disease, inflammatory bowel disease, crohn's disease or ulcerative bowel disease. In addition, the skin and subcutaneous tissue disease may be psoriasis. Furthermore, musculoskeletal and connective tissue diseases may be rheumatoid arthritis, osteoarthritis or Systemic Lupus Erythematosus (SLE). Furthermore, congenital malformations, variations and chromosomal abnormalities may be autosomal dominant polycystic kidney disease.

Stereoisomers and pharmaceutically acceptable salts are as described above for stereoisomers and pharmaceutically acceptable salts of the compounds of formula I of the invention.

For administration, the pharmaceutical composition of the present invention may comprise at least one or more pharmaceutically acceptable carriers in addition to the compound of formula I, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof. The pharmaceutically acceptable carrier may be saline, sterile water, ringer's solution, buffered saline, dextrose solution, maltodextrin solution, glycerol, ethanol or mixtures of one or more of these ingredients, and if desired, other conventional additives such as antioxidants, buffers, bacteriostats and the like. In addition, diluents, dispersants, surfactants, binders and lubricants may be additionally added, and may be formulated into injectable forms (e.g., aqueous solutions, suspensions, emulsions, etc.), pills, capsules, granules or tablets. Thus, the pharmaceutical composition of the present invention may be a patch, a liquid, a pill, a capsule, a granule, a tablet, a suppository, or the like. These formulations may be prepared by conventional methods for formulation in the art or the methods disclosed in literature [ see Remington's Pharmaceutical Science (latest edition), mack Publishing Company, easton PA ], and may be formulated into various formulations according to each disease or ingredient.

The compositions of the present invention may be administered orally or parenterally (e.g., intravenously, subcutaneously, intraperitoneally, or topically) according to a desired method, with dosages varying according to the weight, age, sex, health, diet, time of administration, method of administration, rate of excretion, and severity of the disease of the patient. The compounds of formula I of the present invention may be administered separately and one or more times per day at a daily dose of about 1 to 1000mg/kg, preferably 5 to 100 mg/kg.

The pharmaceutical composition of the present invention may contain at least one active ingredient exhibiting the same or similar efficacy in addition to the compound represented by formula I, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof.

According to one embodiment of the present invention there is provided a method for preventing or treating a disease associated with histone deacetylase 6 activity, which comprises administering to a subject in need thereof a therapeutically effective amount of a compound represented by formula I, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof. The subject may be a mammal, including a human.

Methods for preventing or treating diseases associated with histone deacetylase 6 activity include not only treating the disease itself before the occurrence of symptoms but also inhibiting or avoiding the symptoms thereof by administering a compound represented by formula I, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof. In addition, the method for preventing or treating diseases associated with histone deacetylase 6 activity according to the present invention may further administer a therapeutically effective amount of an additional active agent useful in treating diseases together with the compound represented by formula I, wherein the additional active agent may exhibit a synergistic or auxiliary effect together with the compound represented by formula I described above.

The term "therapeutically effective amount" as used herein refers to an amount of a compound of formula I that is effective to treat or prevent a disorder associated with histone deacetylase 6 activity. In particular, "pharmaceutically effective amount" refers to an amount sufficient to treat a disease at a reasonable benefit/risk ratio applicable to medical treatment, and effective dosage levels may be determined based on factors including the type and severity of the subject, age, sex, type of disease, pharmaceutical activity, sensitivity to the drug, time of administration, route of administration, rate of excretion, duration of treatment, simultaneous use of the drug, and other factors well known in the medical arts. The pharmaceutical compositions of the present invention may be administered as a single therapeutic agent or in combination with other therapeutic agents, and may be administered sequentially or simultaneously with commercially available therapeutic agents. Furthermore, the pharmaceutical compositions of the present invention may be administered in single or multiple doses. In view of all the above, it is important to administer at a minimum dose to obtain maximum effect without side effects, as can be easily determined by a person skilled in the art. The dosage of the pharmaceutical composition of the present invention to be administered may be determined by an expert according to various factors such as the condition, age, sex, complications of the patient, etc. Since the active ingredient of the pharmaceutical composition of the present invention has excellent safety, the active ingredient can be used even at a predetermined dose or more.

According to one embodiment of the present invention, there is provided a method for selectively inhibiting histone deacetylase 6 (HDAC 6) by administering a compound represented by formula I, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof, to a mammal, including a human.

According to one embodiment of the present invention, there is provided the use of a compound represented by formula I, a stereoisomer thereof or a pharmaceutically acceptable salt thereof.

According to one embodiment of the present invention, there is provided the use of a compound represented by formula I, a stereoisomer thereof or a pharmaceutically acceptable salt thereof in the manufacture of a medicament for the treatment of a disease associated with histone deacetylase 6 activity. The compound represented by the chemical formula I for preparing the medicine can be mixed with acceptable auxiliary materials, diluents, carriers and the like, and can be prepared into a combined preparation with other active agents so as to exert the synergistic effect of the active ingredients.

According to one embodiment of the present invention, there is provided the use of a compound represented by formula I, a stereoisomer thereof or a pharmaceutically acceptable salt thereof for the prevention or treatment of a histone deacetylase 6 mediated disease. The compound represented by the formula I for preventing or treating histone deacetylase 6-mediated diseases may be mixed with acceptable auxiliary materials, diluents, carriers, etc., and may be formulated into a combined preparation with other active agents to exert synergistic effects of the active ingredients.

The matters mentioned in the use, composition and method of treatment of the present invention are equally applicable, provided they are not mutually contradictory.

The exemplary embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the exemplary embodiments described below. Furthermore, the exemplary embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art. Furthermore, unless otherwise indicated, the "comprising" of one component throughout the specification is not meant to exclude other components, but rather means that other components may be further included.

The beneficial effects of the invention are that

The compound represented by the chemical formula I, the stereoisomer or the pharmaceutically acceptable salt thereof can selectively inhibit HDAC6, thereby having very excellent preventing or treating effect on diseases related to histone deacetylase 6 activity.

Detailed Description

Hereinafter, the present invention will be described in more detail with reference to examples and experimental examples. However, these embodiments and the like are merely examples of the present invention, and the scope of the present invention is not limited to these embodiments.

Preparation of 1,3, 4-oxadiazole derivative compounds

The specific method for preparing the compound represented by formula I is as follows.

EXAMPLE 5 Synthesis of the Compound 5,3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- (2-thienyl) -1,3, 4-oxadiazol-2-one

[ Synthesis of 1]6-methyl nicotinoyl hydrazide

To a solution of methyl 6-methylnicotinate (10.000 g,66.151 mmol) dissolved in ethanol (200 mL) at room temperature was added hydrazine monohydrate (32.151 mL,661.507 mmol), and the mixture was stirred at the same temperature for 18 hours. The solvent in the reaction mixture was removed under reduced pressure to give a concentrate. Water was poured into the concentrate, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The resulting product was used without further purification (8.248 g,82.5% as white solid).

[ Step 2] Synthesis of 2- (difluoromethyl) -5- (6-methylpyridin-3-yl) -1,3, 4-oxadiazole

To a solution of 6-methylnicotinyl hydrazide (8.248 g,54.561 mmol) synthesized in step 1 dissolved in tetrahydrofuran (200 mL) at 0 ℃ was added triethylamine (38.024 mL,272.805 mmol), and stirred at the same temperature for 10 minutes. 2, 2-difluoroacetic anhydride (20.349 mL,163.683 mmol) was added to the reaction mixture and stirring was continued for 3 hours at 80 ℃ and then the reaction was stopped by cooling to room temperature. Saturated aqueous sodium bicarbonate was poured into the reaction mixture, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 80 g cartridge; ethyl acetate/hexane=0% to 50%) and concentrated to give the title compound (8.019 g, 69.6%) as a yellow solid.

[ Step 3] Synthesis of 2- (6- (bromomethyl) -pyridin-3-yl) -5- (difluoromethyl) -1,3, 4-oxadiazole

A solution of 2- (difluoromethyl) -5- (6-methylpyridin-3-yl) -1,3, 4-oxadiazole (8.019 g,37.974 mmol), 1-bromopyrrolidin-2, 5-one (NBS, 8.110g,45.569 mmol) and azobisisobutyronitrile (AIBN, 0.264 g,3.797 mmol) synthesized in step 2 was stirred at room temperature in 1, 2-dichloroethane (120 mL) for 6 hours at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous ammonium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 80g cartridge; ethyl acetate/hexane=0% to 40%) and concentrated to give the title compound (3.960 g, 36.0%) as a brown solid.

[ Step 4] Synthesis of thiophene-2-carbohydrazide

To a solution of thiophene-2-carboxylic acid methyl ester (100.00% solution, 0.163mL,1.410 mmol) dissolved in ethanol (10 mL) at room temperature was added hydrazine monohydrate (100.00% solution, 1.367mL,28.100 mmol), stirred at 60 ℃ for 5 hours, and then the reaction was terminated by lowering the temperature to room temperature. The solvent in the reaction mixture was removed under reduced pressure to give a concentrate. To the concentrate was poured saturated aqueous sodium bicarbonate solution, and the reaction mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The resulting product was used without further purification (0.2 g,99.8% as a pale yellow solid).

[ Step 5]5- (2-thienyl) -3H-1,3, 4-oxadiazol-2-one Synthesis

To a solution of thiophene-2-carbohydrazide (100.00%, 0.200g,1.407 mmol) and 1,1' -carbonylbis-1H-imidazole (100.00%, 0.274g,1.690 mmol) synthesized in step 4 dissolved in tetrahydrofuran (10 mL) at room temperature was added triethylamine (100.00% solution, 0.279 mL,2.000 mmol), and stirred overnight at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; methanol/dichloromethane=0% to 10%) and concentrated to give the title compound (0.143 g, 60.450%) as a pale yellow solid.

[ Step 6] Synthesis of Compound 5

To a solution of 5- (2-thienyl) -3H-1,3, 4-oxadiazol-2-one (100.00%, 0.063g,0.350 mmol) and potassium carbonate (100.00%, 0.049g,0.494 mmol) synthesized in step 5 in N, N-dimethylformamide (2 mL) was added 2- [6- (bromomethyl) -3-pyridyl ] -5- (difluoromethyl) -1,3, 4-oxadiazol (100.00%, 0.122g,0.421 mmol) synthesized in step 3, and stirred at the same temperature overnight. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; methanol/dichloromethane=0% to 10%) and concentrated, and the resulting product was then purified by chromatography (SiO ₂, 4g cartridge; methanol/dichloromethane=0% to 10%) and concentrated to give the title compound (0.036 g,26.44% yellow solid).

¹H NMR(400MHz,CDCl₃)δ9.34-9.33(m,1H),8.44(dd,J＝8.2,2.2Hz,1H),7.65(dd,J＝4.0,1.2Hz,1H),7.55-7.52(m,2H),7.17-7.15(m,1H),6.96(t,J＝51.6Hz,1H),5.22(s,2H);LRMS(ES)m/z 378.7(M⁺+1).

The compounds in table 2 below were synthesized according to substantially the same method as in example 5.

TABLE 2

EXAMPLE 45 Synthesis of Compound 45,3- ((5- (5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl) pyridin-2-yl) methyl) -5-phenyl-1, 3, 4-oxadiazol-2 (3H) -thione

[ Step 1] Synthesis of benzohydrazine

A solution of methyl benzoate (0.500 g,2.203 mmol) and hydrazine monohydrate (0.920 mL,7.308 mmol) dissolved in ethanol (12 mL) at room temperature was heated to reflux for 18 h, and then the reaction was stopped by reducing the temperature to room temperature. After removal of the solvent from the reaction mixture under reduced pressure, the resulting product was used without further purification (0.500 g,100.0%, white solid).

Step 2 Synthesis of 5-phenyl-1, 3, 4-oxadiazole-2 (3H) -thione

To a solution of the benzohydrazide synthesized in step 1 (100.00%, 0.500g, 3.6752 mmol) dissolved in ethanol (12 mL) at room temperature was added potassium ethylxanthate (100.00%, 0.589g,3.674 mmol), and the mixture was stirred at the same temperature. The solvent in the reaction mixture was removed under reduced pressure, and then the precipitated solid was filtered, washed with water, and then dried to give the title compound (0.45 g, 68.759%) as a pale yellow solid.

[ Step 3] Synthesis of Compound 45

To a solution of 5-phenyl-1, 3, 4-oxadiazole-2 (3H) -thione (100.00%, 50.000mg, 0.281mmol) synthesized in step 1 dissolved in N, N-dimethylformamide (2 mL) at room temperature was added potassium carbonate (100.00%, 40.000mg,0.404 mmol), and stirred at the same temperature for 0.3 hours. To the reaction mixture was added 2- [6- (bromomethyl) -3-pyridinyl ] -5- (difluoromethyl) -1,3, 4-oxadiazole (100.00%, 100.000mg,0.345 mmol) and stirred for a further 18 hours at 35 ℃. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; hexane/ethyl acetate=100% to 50%) and concentrated to give the title compound (58 mg, 53.36%) as a white solid.

¹H NMR(400MHz,CDCl₃)δ9.32(d,J＝1.6Hz,1H),8.40(dd,J＝8.2,2.2Hz,1H),8.01(dd,J＝8.2,1.4Hz,2H),7.83(d,J＝8.4Hz,1H),7.56-7.51(m,3H),6.96(t,J＝51.6Hz,1H),4.75(s,2H);LRMS(ES)m/z 388.8(M⁺+1).

The compounds in table 3 below were synthesized according to the substantially same method as in example 45.

TABLE 3

EXAMPLE 43 Synthesis of Compound 43,3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-phenyl-1, 3, 4-thiadiazol-2-one

[ Step 1] Synthesis of Benzohydrazide

A solution of methyl benzoate (100.00%, 1.000g,7.345 mmol) and hydrazine monohydrate (100.00%, 3.677g,73.452 mmol) dissolved in ethanol (80 mL) at 90℃was stirred at the same temperature overnight, and then the reaction was terminated by lowering the temperature to room temperature. The solvent was removed from the reaction mixture under reduced pressure to obtain a concentrate. Water was poured into the concentrate, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The resulting product was used without further purification (0.88 g,88.000% as a white solid).

Step 2 Synthesis of phenylthiohydrazide

A solution of the benzohydrazide synthesized in step 1 (100.00%, 0.500g,3.672 mmol) and Lawesson's reagent (100.00%, 1.782g,4.406 mmol) dissolved in toluene (20 mL) at 100℃was stirred at the same temperature overnight, and then the reaction was stopped by reducing the temperature to room temperature. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=0% to 30%) and concentrated to give the title compound (0.31 g,55.455%, white solid).

[ Step 3] Synthesis of 5-phenyl-3H-1, 3, 4-thiadiazol-2-one

A solution of phenylthiohydrazide (100.00%, 0.280g,1.839 mmol) synthesized in step 2 and 1,1' -carbonylbis-1H-imidazole (100.00%, 0.356 g,2.208 mmol) dissolved in dichloromethane (20 mL) at 50℃was stirred overnight at the same temperature. The reaction was then terminated by cooling the temperature to room temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 24g cartridge; ethyl acetate/hexane=0% to 30%) and concentrated to give the title compound (0.25 g,76.264%, white solid).

[ Step 4] Synthesis of Compound 43

A solution of 5-phenyl-3H-1, 3, 4-thiadiazol-2-one (100.00%, 0.050g, 0.281mmol) and potassium carbonate (100.00%, 0.058g,0.420 mmol) synthesized in step 3 were dissolved in N, N-dimethylformamide (5 mL) and stirred at room temperature for 30 minutes. Then, 2- [6- (bromomethyl) -3-pyridinyl ] -5- (difluoromethyl) -1,3, 4-oxadiazole (100.00%, 0.085g,0.293 mmol) and potassium iodide (100.00%, 0.023g,0.139 mmol) were added and stirring was continued at the same temperature overnight. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; ethyl acetate/hexane=0% to 50%) and concentrated to obtain the title compound (0.054 g,49.68%, white solid).

¹H NMR(400MHz,CDCl₃)δ9.33(d,J＝1.6Hz,1H),8.42(dd,J＝8.2,2.2Hz,1H),7.71-7.69(m,2H),7.48-7.43(m,4H),7.08(s,0.2H),6.95(s,0.5H),6.82(s,0.2H),5.43(s,2H);LRMS(ES)m/z 388.0(M⁺+1).

The compounds in table 4 below were synthesized according to the substantially same method as in example 43.

TABLE 4

EXAMPLE 4 Synthesis of the Compound 4,3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [ 2-fluoro-4- [ (4-methyl-1-piperidinyl) methyl ] phenyl ] -1,3, 4-oxadiazol-2-one

[ Step 1] Synthesis of methyl 2-fluoro-4- [ (4-methyl-1-piperidinyl) methyl ] benzoate

A solution of methyl 2-fluoro-4-formylbenzoate (100.00%, 0.300g,1.647 mmol), 4-methylpiperidine (100.00%, 2.000 equivalents, 3.294 mmol) and sodium triacetoxyborohydride (100.00%, 2.000 equivalents, 3.294 mmol) dissolved in dichloromethane (10 mL) at room temperature was stirred overnight at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; ethyl acetate/hexane=0% to 100%) and concentrated to give the title compound (0.43 g,98.41% yellow oil).

[ Step 2] Synthesis of 2-fluoro-4- [ (4-methyl-1-piperidinyl) methyl ] benzohydrazide

A solution of methyl 2-fluoro-4- [ (4-methyl-1-piperidinyl) methyl ] benzoate (100.00%, 0.420g,1.583 mmol) and hydrazine monohydrate (100.00%, 10.000 eq, 15.830 mmol) synthesized in step 1, dissolved in ethanol (10 mL) at 80℃was stirred at the same temperature overnight, and then the reaction was terminated by reducing the temperature to room temperature. After removal of the solvent from the reaction mixture under reduced pressure, the resulting product was used without further purification (0.42 g,100.0%, white solid).

[ Step 3] Synthesis of 5- [ 2-fluoro-4- [ (4-methyl-1-piperidinyl) methyl ] phenyl ] -3H-1,3, 4-oxadiazol-2-one

A solution of 2-fluoro-4- [ (4-methyl-1-piperidinyl) methyl ] benzohydrazine (100.00%, 0.420g,1.583 mmol), triphosgene (100.00%, 0.400 eq, 0.633 mmol) and N, N-diisopropylethylamine (100.00%, 2.000 eq, 3.166 mmol) synthesized in step 2 dissolved in dichloromethane (10 mL) at room temperature was stirred at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=0% to 100%) and concentrated to give the title compound (0.275 g,59.63%, white solid).

[ Step 4] Synthesis of Compound 4

A solution of 5- [ 2-fluoro-4- [ (4-methyl-1-piperidinyl) methyl ] phenyl ] -3H-1,3, 4-oxadiazol-2-one (100.00%, 0.090g,0.309 mmol), 2- [6- (bromomethyl) -3-pyridinyl ] -5- (difluoromethyl) -1,3, 4-oxadiazole (100.00%, 1.200 eq, 0.371 mmol), potassium carbonate (100.00%, 2.000 eq, 0.618 mmol) and potassium iodide (100.00%, 1.100 eq, 0.340 mmol) synthesized in step 3 was dissolved in N, N-dimethylformamide (5 mL) at room temperature was stirred overnight at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; ethyl acetate/hexane=0% to 100%) and concentrated to give the title compound (0.07 g,45.27% as a white solid).

¹H NMR(400MHz,CDCl₃)δ9.25(s,1H),8.37(d,J＝10.0Hz,1H),7.69(t,J＝7.6Hz,1H),7.49(d,J＝8.0Hz,1H),7.21-7.18(m,2H),6.93(t,J＝51.6Hz,1H),5.22(s,2H),3.47(s,2H),2.76(d,J＝11.2Hz,2H),1.95(t,J＝10.8Hz,2H),1.57(d,J＝12.0Hz,2H),1.34-1.20(m,3H),0.89(d,J＝6.0Hz,3H);LRMS(ES)m/z 501.4(M⁺+1).

The compounds in table 5 below were synthesized according to the substantially same method as in example 4.

TABLE 5

EXAMPLE 84 Synthesis of Compound 84,3- ((5- (5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl) pyridin-2-yl) methyl) -5- (3- ((dimethylamino) methyl) phenyl) -1,3, 4-oxadiazol-2 (3H) -thione

[ Synthesis of 1]3- (1, 3-Dioxolan-2-yl) benzoic acid methyl ester

Methyl 3-formylbenzoate (100.00%, 2.000g, 12.183mmol), ethylene glycol (100.00%, 3.781g,60.920 mmol) and 4-methylbenzenesulfonic acid hydrate (100.00%, 0.232g,1.220 mmol) were dissolved in toluene (120 mL) at room temperature, and the resulting mixture was heated under reflux overnight. The mixture was cooled to room temperature, water was then added to the reaction mixture, followed by extraction with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 80g cartridge; ethyl acetate/hexane=0% to 10%) and concentrated to give the title compound (1.8 g, 70.959%) as a white solid.

Step 2 Synthesis of 3- (1, 3-Dioxolane-2-yl) benzohydrazide

A solution of methyl 3- (1, 3-dioxolan-2-yl) benzoate (100.00%, 1.130g,5.427 mmol) and hydrazine monohydrate (100.00%, 2.719 g,54.275 mmol) synthesized in step 1, dissolved in ethanol (80 mL) at 80℃was stirred at the same temperature overnight, and then the reaction was terminated by reducing the temperature to room temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 24g cartridge; methanol/dichloromethane=0% to 5%) and concentrated to give the title compound (1.1 g,97.345%, white solid).

Step 3 Synthesis of 5- [3- (1, 3-Dioxolan-2-yl) phenyl ] -3H-1,3, 4-oxadiazole-2-thione

A solution of 3- (1, 3-dioxolan-2-yl) benzohydrazide (100.00%, 0.900g,4.323 mmol) synthesized in step 2 and potassium ethylxanthate (100.00%, 0.762g,4.754 mmol) dissolved in ethanol (50 mL) at 80℃was stirred at the same temperature overnight, and then the reaction was terminated by reducing the temperature to room temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 24g cartridge; ethyl acetate/hexane=0% to 30%) and concentrated to give the title compound (0.7 g,64.70%, white solid).

[ Step 4] Synthesis of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [3- (1, 3-dioxolan-2-yl) phenyl ] -1,3, 4-oxadiazol-2-thione

A solution of 5- [3- (1, 3-dioxolan-2-yl) phenyl ] -3H-1,3, 4-oxadiazole-2-thione (100.00%, 0.350g,1.398 mmol), 2- [6- (bromomethyl) -3-pyridinyl ] -5- (difluoromethyl) -1,3, 4-oxadiazole (100.00%, 0.426g,1.469 mmol), potassium carbonate (100.00%, 0.208g,2.099 mmol) and potassium iodide (100.00%, 0.116g,0.699 mmol) synthesized in step 3 was stirred at room temperature for 30 minutes and then stirred further overnight at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=0% to 50%) and concentrated to give the title compound (0.51 g,79.39% as a white solid).

Synthesis of [ step 5]3- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-thio-1, 3, 4-oxadiazol-2-yl ] benzaldehyde

A solution of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [3- (1, 3-dioxolan-2-yl) phenyl ] -1,3, 4-oxadiazol-2-thione (100.00%, 0.500g,1.088 mmol) synthesized in step 4 and ferric chloride hexahydrate (100.00%, 1.030g, 3.81mmol) dissolved in dichloromethane (30 mL) was stirred at the same temperature overnight. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=0% to 40%) and concentrated to give the title compound (0.350 g, 77.41%) as a white solid.

[ Step 6] Synthesis of Compound 84

To a solution of 4- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-thio-1, 3, 4-oxadiazol-2-yl ] benzaldehyde (100.00%, 0.030g,0.072 mmol) synthesized in step 5 dissolved in dichloromethane (5 mL) at room temperature was added N-methyl methylamine (100.00%, 0.0070 g,0.155 mmol) and stirred at the same temperature for 30 minutes. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; methanol/dichloromethane=0% to 5%) and concentrated to give the title compound (0.01 g,34.27%, white solid).

¹H NMR(400MHz,CDCl₃)δ9.32(d,J＝1.7Hz,1H),8.39(dd,J＝8.2,2.2Hz,1H),7.94-7.90(m,2H),7.83(d,J＝8.2Hz,1H),7.52-7.45(m,2H),7.08(s,0.2H),6.95(s,0.5H),6.82(s,0.2H),4.74(s,2H),3.50(s,2H),2.28(s,6H);LRMS(ES)m/z 445.23(M⁺+1).

The compounds in table 6 below were synthesized in substantially the same manner as in example 84.

TABLE 6

EXAMPLE 132 Synthesis of Compound 132,5- [4- (azetidin-1-ylmethyl) phenyl ] -3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -1,3, 4-oxadiazol-2-one

[ Synthesis of 1]4- (1, 3-Dioxolan-2-yl) benzoic acid methyl ester

Methyl 4-formylbenzoate (100.00%, 3.000g,18.275 mmol), ethylene glycol (100.00%, 5.67 g,91.380 mmol) and 4-methylbenzenesulfonic acid hydrate (100.00%, 0.348g,1.830 mmol) were dissolved in toluene (150 mL) at room temperature, and the resulting mixture was heated under reflux overnight. The mixture was cooled to room temperature, water was then added to the reaction mixture, followed by extraction with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 80g cartridge; ethyl acetate/hexane=0% to 10%) and concentrated to give the title compound (3.5 g, 91.984%) as a white solid.

Step 2 Synthesis of 4- (1, 3-Dioxolane-2-yl) benzohydrazide

Methyl 4- (1, 3-dioxolan-2-yl) benzoate (100.00%, 2.000g, 9.602 mmol) and hydrazine monohydrate (100.00%, 4.809g,96.065 mmol) synthesized in step 1 were dissolved in ethanol (100 mL) at room temperature, and the resulting mixture was heated to reflux overnight. The mixture was cooled to room temperature, water was then added to the reaction mixture, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 40g cartridge; methanol/dichloromethane=0% to 5%) and concentrated to give the title compound (1.8 g,90.000%, white solid).

Step 3 Synthesis of 5- [4- (1, 3-dioxolan-2-yl) phenyl ] -3H-1,3, 4-oxadiazol-2-one

4- (1, 3-Dioxolan-2-yl) benzohydrazide (100.00%, 0.650g,3.122 mmol) synthesized in step 2 and 1,1' -carbonylbis-1H-imidazole (100.00%, 0.607g,3.744 mmol) were dissolved in dichloromethane (50 mL) at room temperature, and the resulting mixture was heated to reflux overnight. The mixture was cooled to room temperature, water was poured into the reaction mixture, and then extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=0% to 50%) and concentrated to give the title compound (0.45 g,61.545%, white solid).

[ Step 4] Synthesis of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [4- (1, 3-dioxolan-2-yl) phenyl ] -1,3, 4-oxadiazol-2-one

To a solution of 5- [4- (1, 3-dioxolan-2-yl) phenyl ] -3H-1,3, 4-oxadiazol-2-one (100.00%, 0.500g,2.135 mmol) and potassium carbonate (100.00%, 0.447 g,3.205 mmol) synthesized in step 3 dissolved in N, N-dimethylformamide (30 mL) at room temperature was added 2- [6- (bromomethyl) -3-pyridinyl ] -5- (difluoromethyl) -1,3, 4-oxadiazol (100.00%, 0.650g,2.241 mmol) and potassium iodide (100.00%, 0.177g,1.066 mmol), and stirred at the same temperature for 30 minutes. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. Ethyl acetate (5 mL) was added to the concentrate, and the solid was precipitated by stirring, and the precipitated solid was filtered, washed with hexane and dried to obtain the title compound (0.74 g,78.18% as a white solid).

Synthesis of [ step 5]4- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-oxo-1, 3, 4-oxadiazol-2-yl ] benzaldehyde

A solution of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [4- (1, 3-dioxolan-2-yl) phenyl ] -1,3, 4-oxadiazol-2-one (100.00%, 0.280g, 0.630 mmol) synthesized in step 4 and ferric trichloride hexahydrate (100.00%, 0.512g,1.894 mmol) dissolved in dichloromethane (30 mL) was stirred at the same temperature overnight. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=0% to 50%) and concentrated to give the title compound (0.18 g,71.39%, white solid).

Step 6 Synthesis of Compound 132

A solution of 4- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-oxo-1, 3, 4-oxadiazol-2-yl ] benzaldehyde (100.00%, 0.030g,0.075 mmol) and azetidine hydrochloride (100.00%, 0.014g,0.150 mmol) synthesized in step 5 in dichloromethane (5 mL) was stirred at room temperature for 30 min. Then, sodium triacetoxyborohydride (100.00%, 0.048g,0.227 mmol) was added, and stirred at the same temperature overnight. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; methanol/dichloromethane=0% to 5%) and concentrated to give the title compound (0.019 g,57.42%, white solid).

¹H NMR(400MHz,CDCl₃)δ9.33(d,J＝1.5Hz,1H),8.43(dd,J＝8.2,2.2Hz,1H),7.82(d,J＝8.3Hz,2H),7.55-7.52(m,1H),7.43(d,J＝8.1Hz,2H),7.08(s,0.2H),6.95(s,0.5H),6.82(s,0.2H),5.24(s,2H),3.67(s,2H),3.32-3.28(m,4H),2.19-2.12(m,2H);LRMS(ES)m/z 441.3(M⁺+1).

The compounds in table 7 below were synthesized according to the procedure substantially the same as in example 132.

TABLE 7

EXAMPLE 83 Synthesis of Compound 83,3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [4- [ (4-isopropylpiperazin-1-yl) methyl ] phenyl ] -1,3, 4-oxadiazol-2-one

[ Step 1]4 Synthesis of tert-butyl- [ (4-methoxycarbonylphenyl) methyl ] piperazine-1-carboxylate

A solution of methyl 4-formylbenzoate (100.00%, 0.500g,3.046 mmol), tert-butyl piperazine-1-carboxylate (100.00%, 0.681g, 3.650 mmol) and sodium triacetoxyborohydride (100.00%, 1.2911 g,6.091 mmol) dissolved in dichloromethane (20 mL) at room temperature was stirred overnight at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 24g cartridge; ethyl acetate/hexane=0% to 30%) and concentrated to give the title compound (0.89 g,87.38%, white solid).

Step 2 Synthesis of tert-butyl 4- [ [4- (hydrazinocarbonyl) phenyl ] methyl ] piperazine-1-carboxylate

A solution of tert-butyl 4- [ (4-methoxycarbonylphenyl) methyl ] piperazine-1-carboxylate (100.00%, 0.300g,0.897 mmol) and hydrazine monohydrate (100.00%, 0.449g,8.969 mmol) synthesized in step 1, dissolved in ethanol (20 mL) at 90℃was stirred at the same temperature overnight, and then the reaction was terminated by reducing the temperature to room temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The resulting product was used without further purification (0.29 g,96.67%, white solid).

[ Step 3] Synthesis of tert-butyl 4- [ [4- (2-oxo-3H-1, 3, 4-oxadiazol-5-yl) phenyl ] methyl ] piperazine-1-carboxylate

To a solution of tert-butyl 4- [ [4- (hydrazinocarbonyl) phenyl ] methyl ] piperazine-1-carboxylate (100.00%, 0.500g, 1.495mmol) and 1,1' -carbonylbis-1H-imidazole (100.00%, 0.29 g,1.795 mmol) synthesized in step 2 dissolved in tetrahydrofuran (10 mL) at room temperature was added triethylamine (100.00% solution, 0.29mL,2.100 mmol), and stirred at the same temperature overnight. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 24g cartridge; methanol/dichloromethane=0% to 10%) and concentrated to give the title compound (0.4638 g,86.85% as a white solid).

Synthesis of tert-butyl [ step 4]4- [ [4- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-oxo-1, 3, 4-oxadiazol-2-yl ] phenyl ] methyl ] piperazine-1-carboxylate

To a solution of tert-butyl 4- [ [4- (2-oxo-3H-1, 3, 4-oxadiazol-5-yl) phenyl ] methyl ] piperazine-1-carboxylate (100.00%, 0.236g, 0.015 mmol) and potassium carbonate (100.00%, 0.091g, 0.178 mmol) synthesized in step 3 dissolved in N, N-dimethylformamide (3 mL) at room temperature was added 2- [6- (bromomethyl) -3-pyridinyl ] -5- (difluoromethyl) -1,3, 4-oxadiazol (100.00%, 0.228g,0.786 mmol) prepared in step 3 of example 5, and stirred at the same temperature overnight. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified and concentrated by column chromatography (SiO ₂, 4g cartridge; ethyl acetate/hexane=0% to 60%), and then the obtained product was purified and concentrated by chromatography (SiO ₂, 4g cartridge; methanol/dichloromethane=0% to 10%) to obtain the title compound (0.37 g,99.20% white solid).

[ Step 5]3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [4- (piperazin-1-ylmethyl) phenyl ] -1,3, 4-oxadiazol-2-one synthesis

A solution of 4- [ [4- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-oxo-1, 3, 4-oxadiazol-2-yl ] phenyl ] methyl ] piperazine-1-carboxylic acid tert-butyl ester synthesized in step 4 (100.00%, 0.370g,0.650 mmol) and trifluoroacetic acid (100.00% solution, 0.497mL,6.490 mmol) dissolved in dichloromethane (3 mL) at room temperature was stirred overnight at room temperature. Saturated aqueous sodium bicarbonate was poured into the reaction mixture, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The resulting product was used without further purification (0.3 g,98.39%, yellow oil).

[ Step 6] Synthesis of Compound 83

A solution of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [4- (piperazin-1-ylmethyl) phenyl ] -1,3, 4-oxadiazol-2-one (100.00%, 0.075g,0.160 mmol), acetone (100.00% solution, 0.019mL,0.257 mmol) and N-ethyl-N-isopropyl-propan-2-amine (100.00% solution, 0.056mL,0.322 mmol) synthesized in step 5 was stirred at room temperature for 30 minutes. Then, sodium triacetoxyborohydride (100.00%, 0.101g,0.479 mmol) was added, and stirred at the same temperature for 18 hours. Saturated aqueous sodium bicarbonate was poured into the reaction mixture, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; dichloromethane/methanol=0% to 10%) and concentrated to give the title compound (0.014 g, 17.13%) as a pale yellow solid.

¹H NMR(400MHz,CD₃OD)δ9.25(d,J＝1.6Hz,1H),8.53(dd,J＝8.2,2.2Hz,1H),7.85(d,J＝8.4Hz,2H),7.72(d,J＝8.0Hz,1H),7.53(d,J＝8.4Hz,2H),7.26(t,J＝51.6Hz,1H),5.26(s,2H),3.63(s,2H),2.74-2.59(m,9H),1.15(d,J＝6.8Hz,6H);LRMS(ES)m/z 512.8(M⁺+1).

EXAMPLE 66 Synthesis of Compound 66,3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [4- (4-isopropylpiperazin-1-yl) phenyl ] -1,3, 4-thiadiazol-2-one

[ Step 1]4 Synthesis of tert-butyl [4- (aminothiocarbamoyl) phenyl ] methyl ] piperazine-1-carboxylate

A solution of tert-butyl 4- [ [4- (hydrazinocarbonyl) phenyl ] methyl ] piperazine-1-carboxylate (100.00%, 1.000g,2.990 mmol) and Lawesson's reagent (100.00%, 1.457 g,3.587 mmol) synthesized in example 86, step 2, dissolved in toluene (40 mL) at 80℃was stirred at the same temperature overnight. The reaction was then terminated by cooling the temperature to room temperature. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 24g cartridge; ethyl acetate/hexane=0% to 60%) and concentrated to give the title compound (0.61 g,58.20%, white solid).

[ Step 2] Synthesis of tert-butyl 4- [ [4- (2-oxo-3H-1, 3, 4-thiadiazol-5-yl) phenyl ] methyl ] piperazine-1-carboxylate

A solution of tert-butyl 4- [ [4- (aminothiocarbamoyl) phenyl ] methyl ] piperazine-1-carboxylate (100.00%, 0.500g,1.427 mmol) and 1,1' -carbonylbis-1H-imidazole (100.00%, 0.278g, 1.015 mmol) synthesized in step 1, dissolved in dichloromethane (30 mL) at 50℃was stirred at the same temperature overnight. The reaction was then terminated by cooling the temperature to room temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous ammonium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=0% to 40%) and concentrated to give the title compound (0.25 g,46.55%, white solid).

Synthesis of tert-butyl [ step 3]4- [ [4- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-oxo-1, 3, 4-thiadiazol-2-yl ] phenyl ] methyl ] piperazine-1-carboxylate

A solution of tert-butyl 4- [ [4- (2-oxo-3H-1, 3, 4-thiadiazol-5-yl) phenyl ] methyl ] piperazine-1-carboxylate (100.00%, 0.100g,0.266 mmol) and potassium carbonate (100.00%, 0.055g, 0.390 mmol) synthesized in step 2 in N, N-dimethylformamide (10 mL) was stirred at room temperature for 30 minutes. Then, 2- [6- (bromomethyl) -3-pyridinyl ] -5- (difluoromethyl) -1,3, 4-oxadiazole (100.00%, 0.081g,0.279 mmol) and potassium iodide (100.00%, 0.022g,0.133 mmol) were added and stirring was continued at the same temperature overnight. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=0% to 40%) and concentrated to give the title compound (0.095 g,61.08%, white solid).

[ Step 4] Synthesis of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [4- (piperazin-1-ylmethyl) phenyl ] -1,3, 4-thiadiazol-2-one 2, 2-trifluoroacetic acid

A solution of tert-butyl 4- [ [4- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-oxo-1, 3, 4-thiadiazol-2-yl ] phenyl ] methyl ] piperazine-1-carboxylate synthesized in step 3 (100.00%, 0.090g,0.154 mmol) and trifluoroacetic acid (100.00%, 0.053g, 0.460 mmol) dissolved in dichloromethane (10 mL) at room temperature was stirred overnight at the same temperature. After removal of the solvent from the reaction mixture under reduced pressure, the resulting product was used without further purification (0.088 g,95.51%, yellow oil).

[ Step 5] Synthesis of Compound 66

A solution of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [4- (piperazin-1-ylmethyl) phenyl ] -1,3, 4-thiadiazol-2-one 2, 2-trifluoroacetic acid (100.00%, 0.030g,0.051 mmol), acetone (100.00%, 0.006g,0.103 mmol), N-ethyldiisopropylamine (100.00% solution, 0.018mL,0.103 mmol) and sodium triacetoxyborohydride (100.00%, 0.033g,0.156 mmol) synthesized in step 4 was stirred at room temperature for 30 minutes, then stirred overnight at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; methanol/dichloromethane=0% to 5%) and concentrated to give the title compound (0.01 g,41.80%, white solid).

¹H NMR(400MHz,CDCl₃)δ9.33(d,J＝1.6Hz,1H),8.41(dd,J＝8.2,2.2Hz,1H),7.64(d,J＝8.2Hz,2H),7.47(d,J＝8.2Hz,1H),7.41(d,J＝8.2Hz,2H),7.08(s,0.2H),6.95(s,0.5H),6.82(s,0.2H),5.42(s,2H),3.56(s,2H),2.78-2.77(m,1H),2.64-2.48(m,8H),1.11(d,J＝6.5Hz,6H);LRMS(ES)m/z 529.35(M⁺+1).

The compounds in table 8 below were synthesized according to the substantially same method as in example 66.

TABLE 8

EXAMPLE 77 Synthesis of Compound 77,3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [4- [ (4-isopropylpiperazin-1-yl) methyl ] phenyl ] -1,3, 4-oxadiazol-2-thione

[ Synthesis of 1]4- (4- (5-thio-4, 5-dihydro-1, 3, 4-oxadiazol-2-yl) benzyl) piperazine-1-carboxylic acid tert-butyl ester

A mixture of tert-butyl 4- [ [4- (hydrazinocarbonyl) phenyl ] methyl ] piperazine-1-carboxylate prepared in step 2 of example 86 (100.00%, 1.000g,2.990 mmol) and potassium ethylxanthate (100.00%, 0.575g,3.587 mmol) in ethanol (80 mL) was heated at reflux overnight. The mixture was cooled to room temperature, water was poured into the reaction mixture, and then extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 24g cartridge; ethyl acetate/hexane=0% to 40%) and concentrated to give the title compound (0.85 g,75.50%, white solid).

Synthesis of tert-butyl [ step 2]4- [ [4- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-thio-1, 3, 4-oxadiazol-2-yl ] phenyl ] methyl ] piperazine-1-carboxylate

A solution of tert-butyl 4- [ [4- (2-thio-3H-1, 3, 4-oxadiazol-5-yl) phenyl ] methyl ] piperazine-1-carboxylate (100.00%, 0.500g,1.328 mmol) and potassium carbonate (100.00%, 0.197g,1.988 mmol) synthesized in step 1 was dissolved in N, N-dimethylformamide (30 mL) was stirred at room temperature for 30 minutes. Then, 2- [6- (bromomethyl) -3-pyridinyl ] -5- (difluoromethyl) -1,3, 4-oxadiazole (100.00%, 0.404g,1.393 mmol) and potassium iodide (100.00%, 0.110g,0.663 mmol) were added and stirring was continued at the same temperature overnight. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 24g cartridge; ethyl acetate/hexane=0% to 40%) and concentrated to give the title compound (0.65 g,83.58% as a white solid).

[ Step 3] Synthesis of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [4- (piperazin-1-ylmethyl) phenyl ] -1,3, 4-oxadiazol-2-thione 2, 2-trifluoroacetic acid

A solution of tert-butyl 4- [ [4- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-thio-1, 3, 4-oxadiazol-2-yl ] phenyl ] methyl ] piperazine-1-carboxylate synthesized in step 2 (100.00%, 0.300g,0.512 mmol) and trifluoroacetic acid (100.00%, 0.175g,1.535 mmol) dissolved in dichloromethane (20 mL) at room temperature was stirred at the same temperature for 3 hours. After removal of the solvent from the reaction mixture under reduced pressure, the resulting product was used without further purification (0.28 g,91.17%, yellow oil).

[ Step 4] Synthesis of Compound 77

A solution of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [4- (piperazin-1-ylmethyl) phenyl ] -1,3, 4-oxadiazol-2-thione 2, 2-trifluoro-acetic acid (100.00%, 0.050g,0.083 mmol), acetone (100.00%, 0.010g,0.172 mmol) and N-ethyldiisopropylamine (100.00% solution, 0.029mL,0.167 mmol) synthesized in step 3 was stirred at room temperature for 30 minutes. Then, sodium triacetoxyborohydride (100.00%, 0.053g,0.250 mmol) was added, and stirring was continued at the same temperature overnight. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; methanol/dichloromethane=0% to 5%) and concentrated to give the title compound (0.022 g,50.00%, white solid).

¹H NMR(400MHz,CDCl₃)δ9.31(d,J＝2.2Hz,1H),8.39(dd,J＝8.2,2.2Hz,1H),7.95(d,J＝8.3Hz,2H),7.82(d,J＝8.2Hz,1H),7.46(d,J＝8.3Hz,2H),7.08(s,0.2H),6.95(s,0.5H),6.82(s,0.2H),4.73(s,2H),3.60(s,2H),3.16-2.92(m,1H),2.81-2.76(m,8H),1.19(d,J＝6.5Hz,6H);LRMS(ES)m/z 528.87(M⁺+1).

The compounds in table 9 below were synthesized in substantially the same manner as in example 77.

TABLE 9

EXAMPLE 26 Synthesis of Compound 26,3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [ 2-fluoro-3- [1- (oxetan-3-yl) -4-piperidinyl ] phenyl ] -1,3, 4-oxadiazol-2-one

[ Synthesis of 1]4- (2-fluoro-3-methoxycarbonyl-phenyl) -3, 6-dihydro-2H-pyridine-1-carboxylic acid tert-butyl ester

A solution of methyl 3-bromo-2-fluoro-benzoate (100.00%, 1.000g, 4.2919 mmol), tert-butyl 4- (4, 5-tetramethyl-1, 3, 2-dioxaborane-2-yl) -3, 6-dihydro-2H-pyridine-1-carboxylate (100.00%, 1.460g, 4.720 mmol), bis (triphenylphosphine) palladium (II) dichloride (100.00%, 0.301g, 0.428 mmol) and sodium carbonate (100.00%, 1.365g,12.879 mmol) in N, N-dimethylformamide (20 mL)/water (5 mL) was stirred at room temperature overnight. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 24g cartridge; ethyl acetate/hexane=0% to 30%) and concentrated to give the title compound (1.100 g,76.43%, white solid).

[ Step 2] Synthesis of tert-butyl 4- (2-fluoro-3-methoxycarbonyl-phenyl) piperidine-1-carboxylate

A solution of 4- (2-fluoro-3-methoxycarbonyl-phenyl) -3, 6-dihydro-2H-pyridine-1-carboxylic acid tert-butyl ester synthesized in step 1 (100.00%, 0.900g,2.683 mmol) and Pd/C (100.00%, 0.284 g,2.688 mmol) dissolved in methanol (20 mL) was stirred at the same temperature overnight. The reaction mixture was filtered through a pad of celite to remove solids, and the solvent in the filtrate was removed under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=0% to 40%) and concentrated to give the title compound (0.74 g,81.73% yellow oil).

Step 3 Synthesis of tert-butyl 4- [ 2-fluoro-3- (hydrazinocarbonyl) phenyl ] piperidine-1-carboxylate

A solution of tert-butyl 4- (2-fluoro-3-methoxycarbonyl-phenyl) piperidine-1-carboxylate (100.00%, 0.700g,2.075 mmol) synthesized in step 2 and hydrazine monohydrate (100.00%, 1.039g,20.755 mmol) dissolved in ethanol (30 mL) at room temperature was stirred at the same temperature overnight. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The resulting product was used without further purification (0.65 g,92.86% as white solid).

[ Step 4]4 Synthesis of tert-butyl- [ 2-fluoro-3- (2-oxo-3H-1, 3, 4-oxadiazol-5-yl) phenyl ] piperidine-1-carboxylate

A solution of tert-butyl 4- [ 2-fluoro-3- (hydrazinocarbonyl) phenyl ] piperidine-1-carboxylate (100.00%, 0.700g,2.075 mmol) synthesized in step 3 and 1,1' -carbonylbis-1H-imidazole (100.00%, 0.404g,2.492 mmol) dissolved in dichloromethane (30 mL) at room temperature was stirred overnight at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous ammonium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=0% to 40%) and concentrated to give the title compound (0.55 g,72.95%, white solid).

Synthesis of [ step 5]4- [3- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-oxo-1, 3, 4-oxadiazol-2-yl ] -2-fluoro-phenyl ] piperidine-1-carboxylic acid tert-butyl ester

To a solution of 4- [ 2-fluoro-3- (2-oxo-3H-1, 3, 4-oxadiazol-5-yl) phenyl ] piperidine-1-carboxylic acid tert-butyl ester (100.00%, 0.400g,1.101 mmol) and potassium carbonate (100.00%, 0.164g,1.655 mmol) synthesized in step 4 dissolved in N, N-dimethylformamide (20 mL) at room temperature was added 2- [ 6-bromomethyl-3-pyridinyl ] -5-difluoromethyl-1, 3, 4-oxadiazol (100.00%, 0.335g,1.155 mmol) and potassium iodide (100.00%, 0.091g,0.548 mmol) and stirred at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=0% to 40%) and concentrated to give the title compound (0.54 g,85.69%, white solid).

[ Step 6] Synthesis of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [ 2-fluoro-3- (4-piperidinyl) phenyl ] -1,3, 4-oxadiazol-2-one 2, 2-trifluoroacetic acid

A solution of 4- [3- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-oxo-1, 3, 4-oxadiazol-2-yl ] -2-fluoro-phenyl ] piperidine-1-carboxylic acid tert-butyl ester synthesized in step 5 (100.00%, 0.300g,0.524 mmol) and 2, 2-trifluoroacetic acid (100.00%, 0.719 g,1.570 mmol) dissolved in dichloromethane (20 mL) at room temperature was stirred at the same temperature for 3 hours. After removal of the solvent from the reaction mixture under reduced pressure, the resulting product was used without further purification (0.3 g,97.63%, yellow oil).

Step 7 Synthesis of Compound 26

A solution of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [ 2-fluoro-3- (4-piperidinyl) phenyl ] -1,3, 4-oxadiazol-2-one 2, 2-trifluoro-acetic acid (100.00%, 0.050g,0.085 mmol), N-ethyldiisopropylamine (100.00% solution, 0.03mL,0.172 mmol), oxetan-3-one (100.00%, 0.012g,0.167 mmol) and sodium triacetoxyborohydride (100.00%, 0.054g,0.255 mmol) synthesized in step 6, dissolved in dichloromethane (5 mL) at room temperature was stirred at the same temperature overnight. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; methanol/dichloromethane=0% to 5%) and concentrated to give the title compound (0.031 g,68.79%, white solid).

¹H NMR(400MHz,CDCl₃)δ9.32(d,J＝1.6Hz,1H),8.43(dd,J＝8.2,2.2Hz,1H),7.70-7.66(m,1H),7.53(d.J＝8.2Hz,1H),7.47-7.43(m,1H),7.26-7.23(m,1H),7.08(s,0.2H),6.95(s,0.5H),6.82(s,0.2H)5.26(s,2H),4.71-4.64(m,4H),3.56-3.50(m,1H),3.00-2.94(m,1H),2.91-2.88(m,2H),2.02-1.96(m,2H),1.87-1.81(m,4H);LRMS(ES)m/z 529.82(M⁺+1).

The compounds in table 10 below were synthesized according to the substantially same method as in example 26.

TABLE 10

EXAMPLE 27 Synthesis of Compound 27,3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [ 2-fluoro-3- [1- (1-methylazetidin-3-yl) -4-piperidinyl ] phenyl ] -1,3, 4-oxadiazol-2-one

Synthesis of tert-butyl [ step 1]3- [4- [3- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-oxo-1, 3, 4-oxadiazol-2-yl ] -2-fluoro-phenyl ] -1-piperidinyl ] azetidine-1-carboxylate

A solution of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [ 2-fluoro-3- (4-piperidinyl) phenyl ] -1,3, 4-oxadiazol-2-one 2, 2-trifluoro-acetic acid (100.00%, 0.150g,0.256 mmol), N-ethyldiisopropylamine (100.00% solution, 0.089mL,0.511 mmol), 3-oxoazetidine-1-carboxylic acid tert-butyl ester (100.00%, 0.088g,0.514 mmol) and sodium triacetoxyborohydride (100.00%, 0.163g,0.769 mmol) synthesized in step 6 of example 26, dissolved in dichloromethane (5 mL) at room temperature was stirred at the same temperature overnight. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; methanol/dichloromethane=0% to 5%) and concentrated to give the title compound (0.11 g,68.52%, white solid).

Step 2 Synthesis of 5- [3- [1- (azetidin-3-yl) -4-piperidinyl ] -2-fluoro-phenyl ] -3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -1,3, 4-oxadiazol-2-one 2, 2-trifluoroacetic acid

A solution of 3- [4- [3- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-oxo-1, 3, 4-oxadiazol-2-yl ] -2-fluoro-phenyl ] -1-piperidinyl ] azetidine-1-carboxylic acid tert-butyl ester (100.00%, 0.110g,0.175 mmol) synthesized in step 1 and 2, 2-trifluoroacetic acid (100.00%, 0.060g, 0.528 mmol) dissolved in dichloromethane (5 mL) at room temperature was stirred overnight at the same temperature. After removal of the solvent from the reaction mixture under reduced pressure, the resulting product was used without further purification (0.100 g,88.94%, yellow oil).

[ Step 3] Synthesis of Compound 27

A solution of 5- [3- [1- (azetidin-3-yl) -4-piperidinyl ] -2-fluoro-phenyl ] -3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -1,3, 4-oxadiazol-2-one 2, 2-trifluoroacetic acid (100.00%, 0.050g,0.078 mmol), formaldehyde (100.00%, 0.005g,0.167 mmol), N-ethyldiisopropylamine (100.00% solution, 0.027mL,0.155 mmol) and sodium triacetoxyborohydride (100.00%, 0.050g,0.236 mmol) synthesized in step 2 was stirred at room temperature in dichloromethane (5 mL) overnight at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; methanol/dichloromethane=0% to 5%) and concentrated to give the title compound (0.029 g,68.71% as a white solid).

¹H NMR(400MHz,CDCl₃)δ9.31(d,J＝1.6Hz,1H),8.43(dd,J＝8.2,2.2Hz,1H),7.69-7.65(m,1H),7.53(d.J＝8.2Hz,1H),7.45-7.41(m,1H),7.25-7.21(m,1H),7.08(s,0.2H),6.95(s,0.5H),6.82(s,0.2H)5.26(s,2H),3.76(brs,2H),3.09(brs,3H),2.99-2.90(m,3H),2.50(s,3H),2.09-1.94(m,2H),1.87-1.80(m,4H);LRMS(ES)m/z542.86(M⁺+1).

The compounds in table 11 below were synthesized according to the substantially same method as in example 27.

TABLE 11

EXAMPLE 81 Synthesis of Compound 81,5- [3- (1-cyclobutyl-4-piperidinyl) -2-fluoro-phenyl ] -3- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -1,3, 4-oxadiazol-2-thione

[ Step 1]4 Synthesis of tert-butyl- [ 2-fluoro-3- (2-thio-3H-1, 3, 4-oxadiazol-5-yl) phenyl ] piperidine-1-carboxylate

A mixture of tert-butyl 4- [ 2-fluoro-3- (hydrazinocarbonyl) phenyl ] piperidine-1-carboxylate (100.00%, 1.100g,3.260 mmol) prepared in step 3 of example 26 and potassium ethylxanthate (100.00%, 0.627g,3.911 mmol) in ethanol (80 mL) was heated at reflux overnight at room temperature. The mixture was cooled to room temperature, water was then added to the reaction mixture, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous ammonium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 24g cartridge; ethyl acetate/hexane=0% to 40%) and concentrated to give the title compound (0.9 g,72.76% as a white solid).

Step 2 Synthesis of tert-butyl 4- [3- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-thio-1, 3, 4-oxadiazol-2-yl ] -2-fluoro-phenyl ] piperidine-1-carboxylate

A solution of 4- [ 2-fluoro-3- (2-thioxo-3H-1, 3, 4-oxadiazol-5-yl) phenyl ] piperidine-1-carboxylic acid tert-butyl ester (100.00%, 0.500g,1.318 mmol) synthesized in step 1 and potassium carbonate (100.00%, 0.196g,1.978 mmol) dissolved in N, N-dimethylformamide (20 mL) was stirred at room temperature for 30 minutes. Then, 2- [6- (bromomethyl) -3-pyridinyl ] -5- (difluoromethyl) -1,3, 4-oxadiazole (100.00%, 0.401g,1.383 mmol) and potassium iodide (100.00%, 0.109g,0.657 mmol) were added and stirring was continued at the same temperature overnight. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 24g cartridge; ethyl acetate/hexane=0% to 30%) and concentrated to give the title compound (0.61 g,78.64%, white solid).

[ Step 3] Synthesis of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [ 2-fluoro-3- (4-piperidinyl) phenyl ] -1,3, 4-oxadiazol-2-thione 2, 2-trifluoroacetic acid

A solution of 4- [3- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-thio-1, 3, 4-oxadiazol-2-yl ] -2-fluoro-phenyl ] piperidine-1-carboxylic acid tert-butyl ester (100.00%, 0.400g,0.680 mmol) synthesized in step 2 and trifluoroacetic acid (100.00%, 0.232g,2.035 mmol) dissolved in dichloromethane (20 mL) at room temperature was stirred for 3 hours at the same temperature. After removal of the solvent from the reaction mixture under reduced pressure, the resulting product was used without further purification (0.37 g,90.37%, yellow oil).

[ Step 4] Synthesis of Compound 81

A solution of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [ 2-fluoro-3- (4-piperidinyl) phenyl ] -1,3, 4-oxadiazol-2-thione 2, 2-trifluoro-acetic acid (100.00%, 0.050g,0.083 mmol), cyclobutanone (100.00%, 0.012g,0.171 mmol) and N-ethyldiisopropylamine (100.00% solution, 0.029mL,0.167 mmol) synthesized in step 3 was stirred at room temperature for 30 minutes. Then, sodium triacetoxyborohydride (100.00%, 0.053g,0.250 mmol) was added, and stirring was continued at the same temperature overnight. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; methanol/dichloromethane=0% to 5%) and concentrated to give the title compound (0.029 g,64.40% as a white solid).

¹H NMR(400MHz,CDCl₃)δ9.31(d,J＝2.1Hz,1H),8.38(dd,J＝8.2,2.3Hz,1H),7.83-7.79(m,2H),7.49-7.45(m,1H),7.26-7.22(m,1H),7.08(s,0.2H),6.95(s,0.5H),6.82(s,0.2H),4.73(s,2H),3.15-3.12(m,2H),3.03-3.00(m,1H),2.88-2.84(m,1H),2.12-2.02(m,6H),1.98-1.88(m,4H),1.79-1.68(m,2H);LRMS(ES)m/z 543.90(M⁺+1).

The compounds in table 12 below were synthesized according to the substantially same method as in example 81.

TABLE 12

EXAMPLE 100 Synthesis of the Compound 100,3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [6- (4-ethylpiperazin-1-yl) -2-pyridinyl ] -1,3, 4-oxadiazol-2-thione

[ Synthesis of tert-butyl 1]4- (6-methoxycarbonyl-2-pyridinyl) piperazine-1-carboxylate

A solution of methyl 6-fluoropyridine-2-carboxylate (100.00%, 0.500g,3.223 mmol), tert-butyl piperazine-1-carboxylate (100.00%, 1.200g,6.443 mmol) and N, N-diisopropylethylamine (100.00% solution, 0.844mL,4.800 mmol) dissolved in dimethyl sulfoxide (15 mL) at 130℃was stirred at the same temperature overnight, and the reaction was stopped by reducing the temperature to room temperature. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 24g cartridge; ethyl acetate/hexane=0% to 60%) and concentrated to give the title compound (0.736 g,71.05% as yellow solid).

Step 2 Synthesis of tert-butyl 4- [6- (hydrazinocarbonyl) -2-pyridinyl ] piperazine-1-carboxylate

To a solution of tert-butyl 4- (6-methoxycarbonyl-2-pyridinyl) piperazine-1-carboxylate (100.00%, 0.356 g,2.290 mmol) synthesized in step 1 in ethanol (10 mL) was added hydrazine monohydrate (100.00% solution, 1.113mL,22.900 mmol) and stirred at 60 ℃ for 18 hours. The reaction was then terminated by cooling the temperature to room temperature. A saturated aqueous ammonium chloride solution was poured into the reaction mixture, followed by extraction with methylene chloride. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; methanol/dichloromethane=0% to 10%) and concentrated to give the title compound (0.73 g,99.18%, yellow solid).

[ Step 3] Synthesis of 4- [6- (2-thio-3H-1, 3, 4-oxadiazol-5-yl) -2-pyridinyl ] piperazine-1-carboxylic acid tert-butyl ester

A solution of the tert-butyl 4- [6- (hydrazinocarbonyl) -2-pyridinyl ] piperazine-1-carboxylate synthesized in step 2 (100.00%, 0.730g, 2.271mmol) and potassium ethylxanthate (100.00%, 0.264 g, 2.271mmol) dissolved in ethanol (10 mL) at room temperature was stirred at 90℃overnight. The reaction was then terminated by cooling the temperature to room temperature. A saturated aqueous ammonium chloride solution was poured into the reaction mixture, followed by extraction with methylene chloride. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 40g cartridge; dichloromethane/methanol=0% to 10%) and concentrated to give the title compound (0.604 g,73.18% as a yellow solid).

Synthesis of tert-butyl [ step 4]4- [6- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-thio-1, 3, 4-oxadiazol-2-yl ] -2-pyridinyl ] piperazine-1-carboxylate

A solution of the 4- [3- (2-thio-3H-1, 3, 4-oxadiazol-5-yl) phenyl ] piperazine-1-carboxylic acid tert-butyl ester (100.00%, 0.700g,1.932 mmol), 2- [6- (bromomethyl) -3-pyridinyl ] -5- (difluoromethyl) -1,3, 4-oxadiazole (100.00%, 1.000 eq, 1.932 mmol), potassium carbonate (100.00%, 2.000 eq, 3.863 mmol) and potassium iodide (100.00%, 2.000 eq, 3.863 mmol) synthesized in step 3 was dissolved in N, N-dimethylformamide (5 mL) at room temperature was stirred overnight at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=0% to 50%) and concentrated to obtain the title compound (0.14 g,12.68% as a yellow solid).

[ Step 5]3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- (6-piperazin-1-yl-2-pyridinyl) -1,3, 4-oxadiazol-2-thione Synthesis

A solution of 4- [6- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-thio-1, 3, 4-oxadiazol-2-yl ] -2-pyridinyl ] piperazine-1-carboxylic acid tert-butyl ester synthesized in step 4 (100.00%, 0.384g,0.671 mmol) and trifluoroacetic acid (100.00% solution, 0.513mL,6.700 mmol) dissolved in dichloromethane (3 mL) at room temperature was stirred overnight at the same temperature. Saturated aqueous sodium bicarbonate was poured into the reaction mixture, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The resulting product was used without further purification (0.31 g,97.83% yellow oil).

[ Step 6] Synthesis of Compound 100

A solution of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- (6-piperazin-1-yl-2-pyridinyl) -1,3, 4-oxadiazol-2-thione (100.00%, 0.100g,0.212 mmol), acetaldehyde (100.00% solution, 0.024mL,0.429 mmol) and N-ethyl-N-isopropyl-propan-2-amine (100.00% solution, 0.074mL,0.425 mmol) synthesized in step 5 was stirred at room temperature for 30 minutes, sodium triacetoxyborohydride (100.00%, 0.134g,0.635 mmol) was added, and stirring was continued at the same temperature for 18 hours. Saturated aqueous sodium bicarbonate was poured into the reaction mixture, followed by extraction with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; dichloromethane/methanol=0% to 10%) and concentrated to give the title compound (0.026 g,24.55% as a yellow solid).

¹H NMR(400MHz,CDCl₃)δ9.32(d,J＝1.6Hz,1H),8.37(dd,J＝8.2,2.2Hz,1H),7.84(d,J＝8.4Hz,1H),7.63-7.59(m,1H),7.43(d,J＝7.2Hz,1H),6.96(t,J＝51.6Hz,1H),6.78(d,J＝8.8Hz,1H),4.75(s,2H),3.69(t,J＝5.0Hz,4H),2.59(t,J＝5.0Hz,4H),2.50(q,J＝7.2Hz,2H),1.16(t,J＝7.2Hz,3H);LRMS(ES)m/z 501.5(M⁺+1).

The compounds in table 13 below were synthesized according to the substantially same method as in example 100.

TABLE 13

EXAMPLE 41 Synthesis of Compound 41,3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [ 2-fluoro-3- (1-methyl-4-piperidinyl) phenyl ] -1,3, 4-thiadiazol-2-one

[ Step 1]4 Synthesis of tert-butyl- [3- (aminothiocarbamoyl) -2-fluoro-phenyl ] piperidine-1-carboxylate

A solution of tert-butyl 4- [ 2-fluoro-3- (hydrazinocarbonyl) phenyl ] piperidine-1-carboxylate prepared in step 3 of example 26 (100.00%, 0.200g,0.593 mmol) and Lawesson's reagent (100.00%, 0.288g,0.712 mmol) dissolved in toluene (20 mL) at room temperature was stirred overnight at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous ammonium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The resulting product was used without further purification (0.11 g,52.51% as yellow oil).

[ Step 2] Synthesis of tert-butyl 4- [ 2-fluoro-3- (2-oxo-3H-1, 3, 4-thiadiazol-5-yl) phenyl ] piperidine-1-carboxylate

A solution of the 4- [3- (aminothiocarbamoyl) -2-fluoro-phenyl ] piperidine-1-carboxylic acid tert-butyl ester synthesized in step1 (100.00%, 0.200g,0.566 mmol) and 1,1' -carbonylbis-1H-imidazole (100.00%, 0.110g,0.678 mmol) dissolved in methylene chloride (20 mL) at room temperature was stirred overnight at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous ammonium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=0% to 40%) and concentrated to give the title compound (0.15 g,69.86% as a white solid).

Synthesis of tert-butyl [ step 3]4- [3- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-oxo-1, 3, 4-thiadiazol-2-yl ] -2-fluoro-phenyl ] piperidine-1-carboxylate

To a solution of 4- [ 2-fluoro-3- (2-oxo-3H-1, 3, 4-thiadiazol-5-yl) phenyl ] piperidine-1-carboxylic acid tert-butyl ester (100.00%, 0.073g,0.192 mmol) and potassium carbonate (100.00%, 0.029g,0.293 mmol) synthesized in step 2 dissolved in N, N-dimethylformamide (20 mL) at room temperature was added 2- [6- (bromomethyl) -3-pyridinyl ] -5- (difluoromethyl) -1,3, 4-oxadiazol (100.00%, 0.059g,0.203 mmol) and potassium iodide (100.00%, 0.016g,0.096 mmol) and stirred at the same temperature for 30 minutes. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=0% to 30%) and concentrated to obtain the title compound (0.05 g,44.15% as a white solid).

[ Step 4] Synthesis of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [ 2-fluoro-3- (4-piperidinyl) phenyl ] -1,3, 4-thiadiazol-2-one 2, 2-trifluoroacetic acid

A solution of 4- [3- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-oxo-1, 3, 4-thiadiazol-2-yl ] -2-fluoro-phenyl ] piperidine-1-carboxylic acid tert-butyl ester synthesized in step 3 (100.00%, 0.058g,0.099 mmol) and trifluoroacetic acid (100.00%, 0.034g,0.298 mmol) dissolved in dichloromethane (10 mL) at room temperature was stirred at the same temperature for 3 hours. After removal of the solvent from the reaction mixture under reduced pressure, the resulting product was used without further purification (0.055 g,92.64%, yellow oil).

[ Step 5] Synthesis of Compound 41

A solution of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [ 2-fluoro-3- (4-piperidinyl) phenyl ] -1,3, 4-thiadiazol-2-one 2, 2-trifluoroacetic acid (100.00%, 0.055g,0.091 mmol), N-ethyldiisopropylamine (100.00% solution, 0.032mL,0.184 mmol), formaldehyde (100.00%, 0.005g,0.167 mmol) and sodium triacetoxyborohydride (100.00%, 0.039g,0.184 mmol) synthesized in step 4 in dichloromethane (5 mL) was stirred at room temperature overnight at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; methanol/dichloromethane=0% to 5%) and concentrated to give the title compound (0.031 g,67.58%, white solid).

¹H NMR(400MHz,CDCl₃)δ9.32(d,J＝1.6Hz,1H),8.41(dd,J＝8.2,2.2Hz,1H),7.77-7.73(m,1H),7.46(d,J＝8.2Hz,1H),7.40-7.36(m,1H),7.28-7.17(m,1H),5.44(s,2H),3.13-3.10(m,2H),2.99-2.92(m,1H),2.43(s,3H),2.26-2.20(m,2H),1.98-1.86(m,4H);LRMS(ES)m/z 503.7(M⁺+1).

The compounds in table 14 below were synthesized according to the substantially same method as in example 41.

TABLE 14

EXAMPLE 20 Synthesis of the Compound 20,3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- (4-piperazin-1-ylphenyl) -1,3, 4-oxadiazol-2-one

[ Synthesis of tert-butyl 1]4- (4-methoxycarbonylphenyl) piperazine-1-carboxylate

A solution of methyl 4-bromobenzoate (100.00%, 0.500g,2.325 mmol), tert-butyl piperazine-1-carboxylate (100.00%, 1.200 eq., 2.790 mmol), tris (dibenzylideneacetone) dipalladium (100.00%, 5.000mol%,0.116 mmol), xphos (100.00%, 5.000mol%,0.116 mmol) and cesium carbonate (100.00%, 2.000 eq., 4.650 mmol) dissolved in toluene (50 mL) at 110℃was stirred overnight at the same temperature. The reaction was then terminated by cooling the temperature to room temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=0% to 30%) and concentrated to obtain the title compound (0.73 g,97.99%, brown solid).

Step 2 Synthesis of tert-butyl 4- [4- (hydrazinocarbonyl) phenyl ] piperazine-1-carboxylate

The solution of tert-butyl 4- (4-methoxycarbonylphenyl) piperazine-1-carboxylate (100.00%, 0.770g,2.403 mmol) and hydrazine monohydrate (100.00%, 10.000 eq., 24.030 mmol) synthesized in step 1, dissolved in dichloromethane (5 mL) at room temperature, was stirred at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12 g cartridge; ethyl acetate/hexane=0% to 30%) and concentrated to give the title compound (0.77 g,100.0% as a yellow solid).

[ Step 3] Synthesis of tert-butyl 4- [4- (2-oxo-3H-1, 3, 4-oxadiazol-5-yl) phenyl ] piperazine-1-carboxylate

The solution of tert-butyl 4- [4- (hydrazinocarbonyl) phenyl ] piperazine-1-carboxylate (100.00%, 0.770 g,2.403 mmol) and 1,1' -carbonylbis-1H-imidazole (100.00%, 1.500 eq, 3.605 mmol) synthesized in step 2, dissolved in dichloromethane (5 mL) was heated to reflux overnight. The reaction was then terminated by cooling the temperature to room temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12 g cartridge; ethyl acetate/hexane=0% to 100%) and concentrated to give the title compound (0.5 g,60.06% yellow solid).

Synthesis of [ step 4]4- [4- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-oxo-1, 3, 4-oxadiazol-2-yl ] phenyl ] piperazine-1-carboxylic acid tert-butyl ester

The solution of tert-butyl 4- [4- (2-oxo-3H-1, 3, 4-oxadiazol-5-yl) phenyl ] piperazine-1-carboxylate (100.00%, 0.500 g,1.443 mmol) and 2- [6- (bromomethyl) -3-pyridinyl ] -5- (difluoromethyl) -1,3, 4-oxadiazole (100.00%, 1.200 eq, 1.732 mmol), potassium carbonate (100.00%, 2.000 eq, 2.887 mmol) and potassium iodide (100.00%, 1.100 eq, 1.588 mmol) synthesized in step 3 were dissolved in N, N-dimethylformamide (25 mL) at room temperature was stirred at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12. 12 g cartridge; ethyl acetate/hexane=0% to 50%) and concentrated to obtain the title compound (0.9 g,112.2% as a yellow solid).

Step 5 Synthesis of Compound 20,3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- (4-piperazin-1-ylphenyl) -1,3, 4-oxadiazol-2-one

A solution of 4- [4- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-oxo-1, 3, 4-oxadiazol-2-yl ] phenyl ] piperazine-1-carboxylic acid tert-butyl ester synthesized in step 4 (100.00%, 0.900g,1.620 mmol) and 2, 2-trifluoroacetic acid (100.00%, 10.000 equivalents, 16.200 mmol) dissolved in dichloromethane (50 mL) at room temperature was stirred at the same temperature. The aqueous solution of N-sodium hydrogencarbonate was poured into the reaction mixture, followed by extraction with methylene chloride. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; dichloromethane/methanol=0% to 10%) and concentrated to give the title compound (0.12 g,16.26%, white solid).

¹H NMR(400MHz,CDCl₃)δ9.29(s,1H),8.39(d,J＝10.0Hz,1H),7.70(d,J＝8.8Hz,2H),7.49(d,J＝8.0Hz,1H),7.06-6.80(m,3H),5.18(s,2H),3.27(s,4H),3.02(s,4H);LRMS(ES)m/z 455.5(M⁺+1).

The compounds in table 15 below were synthesized according to the substantially same method as in example 20.

TABLE 15

EXAMPLE 21 Synthesis of Compound 21,3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [4- (4-methylpiperazin-1-yl) phenyl ] -1,3, 4-oxadiazol-2-one

A solution of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- (4-piperazin-1-ylphenyl) -1,3, 4-oxadiazol-2-one (100.00%, 0.060g,0.132 mmol), sodium triacetoxyborohydride (100.00%, 2.000 equivalents, 0.264 mmol) and formaldehyde (37.00%, 2.000 equivalents, 0.264 mmol) synthesized in step 5 of example 20 dissolved in dichloromethane (5 mL) at room temperature was stirred at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; dichloromethane/methanol=0% to 10%) and concentrated to give the title compound (0.025 g,40.42% as a yellow solid).

¹H NMR(400MHz,CDCl₃)δ9.29(s,1H),8.39(d,J＝10.4Hz,1H),7.70(d,J＝8.8Hz,2H),7.50(d,J＝8.0Hz,1H),6.93-6.80(m,3H),5.18(s,2H),3.34(s,4H),2.59(s,4H),2.36(s,3H);LRMS(ES)m/z 470.6(M⁺+1).

The compounds in table 16 below were synthesized according to the substantially same method as in example 21.

TABLE 16

EXAMPLE 6 Synthesis of the Compound 6,3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- [6- (4-isopropylpiperazin-1-yl) -2-pyridinyl ] -1,3, 4-oxadiazol-2-one

[ Synthesis of 1]6-fluoropyridine-2-carbohydrazide

To a solution of methyl 6-fluoropyridine-2-carboxylate (100.00%, 1.000g, 6.4476 mmol) dissolved in ethanol (30 mL) at room temperature was added hydrazine monohydrate (100.00% solution, 6.266mL,129.000 mmol) and stirred at the same temperature overnight. To a concentrate obtained by removing the solvent in the reaction mixture under reduced pressure, a saturated aqueous sodium hydrogencarbonate solution was poured, and the resultant mixture was extracted with methylene chloride. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The resulting product was used without further purification (1 g,100.00%, pale yellow solid).

[ Step 2] Synthesis of 5- (6-fluoro-2-pyridinyl) -3H-1,3, 4-oxadiazol-2-one

To a solution of 6-fluoropyridine-2-carbohydrazide (100.00%, 1.000g, 6.4476 mmol) and 1,1' -carbonylbis-1H-imidazole (100.00%, 1.254g, 7.284 mmol) synthesized in step 1 dissolved in tetrahydrofuran (30 mL) at room temperature was added triethylamine (100.00% solution, 1.251mL,9.000 mmol), and stirred overnight at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; methanol/dichloromethane=0% to 10%) and concentrated to give the title compound (0.21 g,17.987% yellow solid).

[ Step 3] Synthesis of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- (6-fluoro-2-pyridinyl) -1,3, 4-oxadiazol-2-one

To a solution of 5- (6-fluoro-2-pyridinyl) -3H-1,3, 4-oxadiazol-2-one (100.00%, 0.210g,1.160 mmol) and potassium carbonate (100.00%, 0.244g,1.765 mmol) synthesized in step 2, dissolved in N, N-dimethylformamide (5 mL) at room temperature was added 2- [6- (bromomethyl) -3-pyridinyl ] -5- (difluoromethyl) -1,3, 4-oxadiazol (100.00%, 0.404g,1.393 mmol), and stirred at the same temperature overnight. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; methanol/dichloromethane=0% to 10%) and concentrated to give the title compound (0.185 g,40.88% as a pale yellow solid).

[ Step 4] Synthesis of Compound 6

The solution of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- (6-fluoro-2-pyridinyl) -1,3, 4-oxadiazol-2-one (100.00%, 0.040g,0.103 mmol), 1-isopropylpiperazine (100.00% solution, 0.029mL,0.203 mmol) and N, N-diisopropylethylamine (100.00% solution, 0.027mL,0.150 mmol) synthesized in step 3 was stirred at the same temperature overnight, then the reaction was terminated by lowering the temperature to room temperature. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; methanol/dichloromethane=0% to 10%) and concentrated to give the title compound (0.02 g, 39.15%) as an orange solid.

¹H NMR(400MHz,CDCl₃)δ9.32(d,J＝1.6Hz,1H),8.43(dd,J＝8.2,2.2Hz,1H),7.61-7.57(m,1H),7.52(d,J＝8.0Hz,1H),7.23(d,J＝7.6Hz,1H),6.96(t,J＝51.6Hz,1H),6.78(d,J＝8.8Hz,1H),5.27(s,2H),3.76(s,4H),2.89-2.75(m,5H),1.18(d,J＝5.6Hz,6H);LRMS(ES)m/z 499.8(M⁺+1).

The compounds in table 17 below were synthesized according to the substantially same method as in example 6.

TABLE 17

EXAMPLE 19 Synthesis of Compound 19,3- ((5- (5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl) pyridin-2-yl) methyl) -5- (1-methyl-1H-indol-5-yl) -1,3, 4-oxadiazol-2 (3H) -thione

[ Step 1] Synthesis of methyl 1-methylindole-5-carboxylate

To a solution of methyl 1H-indole-5-carboxylate (100.00%, 0.500g,2.854 mmol) dissolved in N, N-dimethylformamide (7 mL) at 0deg.C was added sodium hydride (60.00%, 140.000mg,3.500 mmol) and stirred at the same temperature for 0.2 hours. Methyl iodide (100.00% solution, 0.27mL,4.340 mmol) was added to the reaction mixture and stirred at room temperature for an additional 4 hours. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=0% to 30%) and concentrated to give the title compound (0.27 g,49.996% as a white solid).

[ Step 2] Synthesis of 1-methylindole-5-carbohydrazide

Methyl 1-methylindole-5-carboxylate (100.00%, 160.000mg,0.846 mmol) synthesized in step 1 was dissolved in ethanol (2.5 mL), and hydrazine monohydrate (100.00% solution, 0.8mL,16.490 mmol) was added at room temperature and stirred at 60℃for 18 hours. Then, the temperature was lowered to room temperature to terminate the reaction. After removal of the solvent from the reaction mixture under reduced pressure, the resulting product was used without further purification (160 mg,100.00%, pale yellow solid).

[ Step 3] Synthesis of 5- (1-methylindol-5-yl) -3H-1,3, 4-oxadiazol-2-one

To a solution of 1-methylindole-5-carbohydrazide (100.00%, 160.000mg,0.846 mmol) and N, N-diisopropylethylamine (DIPEA, 100.00% solution, 0.3mL,1.700 mmol) synthesized in step 2 dissolved in methylene chloride (3 mL) at 0℃was added triphosgene (100.00%, 100.000mg,0.337 mmol), and stirred at the same temperature. The solvent in the reaction mixture was removed under reduced pressure, and then the concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=10% to 50%) and concentrated to give the title compound (270 mg,148.36%, white solid).

[ Step 4] Synthesis of Compound 19

To a solution of 5- (1-methylindol-5-yl) -3H-1,3, 4-oxadiazol-2-one (100.00%, 50.000mg,0.232 mmol) synthesized in step 3 dissolved in N, N-dimethylformamide (2 mL) at room temperature was added potassium carbonate (100.00%, 35,000mg,0.353 mmol), and stirred at the same temperature for 0.3 hours. To the reaction mixture was added 2- [6- (bromomethyl) -3-pyridinyl ] -5- (difluoromethyl) -1,3, 4-oxadiazole (100.00%, 80,000mg,0.276 mmol) and stirred for a further 18 hours at 35 ℃. A saturated aqueous sodium chloride solution was poured into the reaction mixture, and extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; hexane/ethyl acetate=100% to 50%) and concentrated to obtain the title compound (43 mg,43.61%, white solid).

¹H NMR(400MHz,CD₃OD)δ9.27(d,J＝1.2Hz,1H),8.52(dd,J＝8.4,2.4Hz,1H),8.10(d,J＝0.8Hz,1H),7.80(s,1H),7.70(t,J＝8.8Hz,1H),7.48(d,J＝8.8Hz,1H),7.26(d,J＝3.2Hz,1H),7.21(t,J＝51.6Hz,1H),6.57(dd,J＝3.2,0.4Hz,1H),5.25(s,2H),3.86(s,3H);LRMS(ES)m/z 425.7(M⁺+1).

The compounds in table 18 below were synthesized according to the substantially same method as in example 19.

TABLE 18

EXAMPLE 33 Synthesis of Compound 33,3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- (1H-indol-6-yl) -1,3, 4-oxadiazol-2-one

[ Step 1] Synthesis of 1-tert-Butoxycarbonylindole-6-carboxylic acid

To a solution of 1H-indole-6-carboxylic acid (100.00%, 1.000g,6.205 mmol) and di-tert-butyl carbonate diester (100.00%, 2.000g,9.164 mmol) dissolved in tetrahydrofuran (12 mL) at room temperature was added 4- (dimethylamino) pyridine (100.00%, 0.150g,1.228 mmol) and stirred at the same temperature for 18 hours. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 24g cartridge; ethyl acetate/hexane=0% to 30%) and concentrated to give the title compound (0.8 g,49.34%, white solid).

[ Synthesis of 2]6- (hydrazinocarbonyl) -1H-indole-1-carboxylic acid tert-butyl ester

To a solution of 1-t-butoxycarbonylindole-6-carboxylic acid (100.00%, 250mg,0.9568 mmol) synthesized in step 1 dissolved in tetrahydrofuran (5 mL) at room temperature was added 1,1' -carbonylbis-1H-imidazole (100.00%, 200.000mg,1.233 mmol), and stirred at the same temperature for 3 hours. Hydrazine monohydrate (100.00%, 145.000mg,2.897 mmol) was added to the reaction mixture and stirred at the same temperature for an additional 18 hours. After removal of the solvent from the reaction mixture under reduced pressure, the resulting product was used without further purification (mixture, pale yellow solid).

[ Synthesis of 3]6- (2-oxo-3H-1, 3, 4-oxadiazol-5-yl) indole-1-carboxylic acid tert-butyl ester

Tert-butyl 6- (hydrazinocarbonyl) indole-1-carboxylate synthesized in step 2 (100.00%, 450.000mg,1.635 mmol) and N, N-diisopropylethylamine (100.00% solution, 0.56mL,3.200 mmol) were dissolved in dichloromethane (5 mL), triphosgene (100.00%, 190.000mg,0.640 mmol) was added at 0℃and stirred at room temperature for 18 hours. The solvent in the reaction mixture was removed under reduced pressure, and then the concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=10% to 50%) and concentrated to obtain the title compound (270 mg,54.82%, white solid).

Synthesis of [ step 4]6- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-oxo-1, 3, 4-oxadiazol-2-yl ] indole-1-carboxylic acid tert-butyl ester

To a solution of tert-butyl 6- (2-oxo-3H-1, 3, 4-oxadiazol-5-yl) indole-1-carboxylate (100.00%, 55.000mg, 0.183mmol) synthesized in step 3 dissolved in N, N-dimethylformamide (2 mL) at room temperature was added potassium carbonate (100.00%, 25.000mg,0.252 mmol) and stirred at the same temperature for 0.3 hours. To the reaction mixture was added 2- [6- (bromomethyl) -3-pyridinyl ] -5- (difluoromethyl) -1,3, 4-oxadiazole (100.00%, 64,000mg,0.221 mmol) and stirred for a further 18 hours at 35 ℃. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; hexane/ethyl acetate=100% to 50%) and concentrated to obtain the title compound (58 mg,62.25%, white solid).

[ Step 5] Synthesis of Compound 33

To a solution of tert-butyl 6- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-oxo-1, 3, 4-oxadiazol-2-yl ] indole-1-carboxylate (100.00%, 50.000mg,0.098 mmol) synthesized in step 4 dissolved in dichloromethane (1 mL) at room temperature was added trifluoroacetic acid (100.00% solution, 0.3mL,3.918 mmol) and stirred at the same temperature for 1 hour. To the concentrate obtained by removing the solvent from the reaction mixture under reduced pressure, a saturated aqueous sodium hydrogencarbonate solution was poured, and the resultant mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; dichloromethane/methanol=100% to 80%) and concentrated to give the title compound (34 mg,84.59% as a pale yellow solid).

¹H NMR(400MHz,CD₃OD)δ9.27(d,J＝1.6Hz,1H),8.54(dd,J＝8.2,2.2Hz,1H),7.93(d,J＝0.8Hz,1H),7.73(d,J＝8.4Hz,1H),7.67(d,J＝8.4Hz,1H),7.53(dd,J＝8.4,1.6Hz,1H),7.44(d,J＝1.2Hz,1H),7.26(t,J＝51.6Hz,1H),5.26(s,2H);LRMS(ES)m/z 412.8(M⁺+1).

The compounds in table 19 below were synthesized according to the substantially same method as in example 33.

TABLE 19

EXAMPLE 11 Synthesis of the Compound 11,3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- (1, 2,3, 4-tetrahydroisoquinolin-6-yl) -1,3, 4-oxadiazol-2-one

[ Synthesis of 1]7- (hydrazinocarbonyl) -3, 4-dihydro-1H-isoquinoline-2-carboxylic acid tert-butyl ester

A solution of 2-tert-butyl, 7-methyl-3, 4-dihydro-1H-isoquinoline-2, 7-dicarboxylic acid ester (100.00%, 0.603g,2.070 mmol) and hydrazine monohydrate (100.00%, 10.000 equivalents, 20.700 mmol) dissolved in ethanol (20 mL) at 70℃was stirred at the same temperature overnight, then the reaction was terminated by reducing the temperature to room temperature. After removal of the solvent from the reaction mixture under reduced pressure, the resulting product was used without further purification (0.603 g,100.0%, white solid).

[ Synthesis of 2]7- (2-oxo-3H-1, 3, 4-oxadiazol-5-yl) -3, 4-dihydro-1H-isoquinoline-2-carboxylic acid tert-butyl ester

A solution of 7- (hydrazinocarbonyl) -3, 4-dihydro-1H-isoquinoline-2-carboxylic acid tert-butyl ester (100.00%, 0.640g, 2.197mmol) synthesized in step 1 and 1,1' -carbonylbis-1H-imidazole (100.00%, 1.500 eq, 3.296 mmol) dissolved in dichloromethane (5 mL) at 50℃was stirred at the same temperature overnight, then the reaction was stopped by reducing the temperature to room temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; ethyl acetate/hexane=0% to 100%) and concentrated to give the title compound (0.42 g,60.25%, white solid).

[ Step 3] Synthesis of 7- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-oxo-1, 3, 4-oxadiazol-2-yl ] -3, 4-dihydro-1H-isoquinoline-2-carboxylic acid tert-butyl ester

A solution of 7- (2-oxo-3H-1, 3, 4-oxadiazol-5-yl) -3, 4-dihydro-1H-isoquinoline-2-carboxylic acid tert-butyl ester (100.00%, 0.420g,1.324 mmol), 2- [6- (bromomethyl) -3-pyridinyl ] -5- (difluoromethyl) -1,3, 4-oxadiazole (100.00%, 1.200 eq, 1.588 mmol), potassium carbonate (100.00%, 2.000 eq, 2.647 mmol) and potassium iodide (100.00%, 1.100 eq, 1.456 mmol) synthesized in step 2 in N, N-dimethylformamide (25 mL) at room temperature was stirred overnight at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane, and the organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=0% to 100%) and concentrated to give the title compound (0.55 g,78.92% as a yellow solid).

[ Step 4] Synthesis of Compound 11

A solution of 7- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5-oxo-1, 3, 4-oxadiazol-2-yl ] -3, 4-dihydro-1H-isoquinoline-2-carboxylic acid tert-butyl ester (100.00%, 0.550g,1.045 mmol) synthesized in step 3 and 2, 2-trifluoroacetic acid (100.00%, 10.000 equivalents, 10.450 mmol) dissolved in dichloromethane (20 mL) at room temperature was stirred overnight at the same temperature. The aqueous solution of N-sodium hydrogencarbonate was poured into the reaction mixture, followed by extraction with methylene chloride. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; dichloromethane/methanol=0% to 10%) and concentrated to give the title compound (0.42 g,94.29%, yellow solid).

¹H NMR(400MHz,CDCl₃)δ9.31(s,1H),8.42(d,J＝8.4Hz,1H),7.60(s,2H),7.51(d,J＝7.6Hz,1H),7.12(d,J＝8.4Hz,1H),6.93(t,J＝51.6Hz,1H),5.21(s,2H),4.09(s,2H),3.19(s,2H),2.88(s,2H);LRMS(ES)m/z 427.4(M⁺+1).

EXAMPLE 12 Synthesis of Compound 12,3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- (2-methyl-3, 4-dihydro-1H-isoquinolin-7-yl) -1,3, 4-oxadiazol-2-one

A solution of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- (1, 2,3, 4-tetrahydroisoquinolin-7-yl) -1,3, 4-oxadiazol-2-one (100.00%, 0.080g,0.188 mmol), formaldehyde (100.00%, 1.500 eq, 0.281 mmol) and sodium triacetoxyborohydride (100.00%, 2.000 eq, 0.375 mmol) synthesized in step 4 of example 11 dissolved in dichloromethane (5 mL) at room temperature was stirred at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; dichloromethane/methanol=0% to 10%) and concentrated to give the title compound (0.02 g,24.21% as yellow solid).

¹H NMR(400MHz,CDCl₃)δ9.27(s,1H),8.38(d,J＝10.4Hz,1H),7.57(d,J＝8.0Hz,1H),7.52(d,J＝25.6Hz,2H),7.17(d,J＝8.0Hz,1H),6.93(t,J＝51.6Hz,1H),5.18(s,2H),3.60(s,2H),2.95(t,J＝5.6Hz,2H),2.72(t,J＝6.0Hz,2H),2.45(s,3H);LRMS(ES)m/z 441.4(M⁺+1).

The compounds in table 20 below were synthesized according to the substantially same method as in example 12.

TABLE 20

EXAMPLE 135 Synthesis of Compound 135,3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -3-fluoro-2-pyridinyl ] methyl ] -5- (2-methyl-3, 4-dihydro-1H-isoquinolin-6-yl) -1,3, 4-oxadiazol-2-thione

[ Synthesis of 1]6- (hydrazinocarbonyl) -3, 4-dihydro-1H-isoquinoline-2-carboxylic acid tert-butyl ester

To a solution of 2-tert-butyl, 6-methyl-3, 4-dihydro-1H-isoquinoline-2, 6-dicarboxylic acid ester (100.00%, 1.000g,3.433 mmol) dissolved in ethanol (20 mL) at room temperature was added hydrazine monohydrate (100.00% solution, 1.668mL,34.320 mmol) and stirred at 60℃overnight. The reaction was then terminated by reducing the temperature to room temperature. The solvent in the reaction mixture was removed under reduced pressure, and then the concentrate was purified by column chromatography (SiO ₂, 24g cartridge; methanol/dichloromethane=0% to 10%) and concentrated to give the title compound (1 g,100.0%, white solid).

[ Synthesis of 2]6- (2-thio-3H-1, 3, 4-oxadiazol-5-yl) -3, 4-dihydro-1H-isoquinoline-2-carboxylic acid tert-butyl ester

A solution of tert-butyl 6- (hydrazinocarbonyl) -3, 4-dihydro-1H-isoquinoline-2-carboxylate (100.00%, 0.640 g,2.204 mmol) and potassium ethylxanthate (100.00%, 0.353g,2.202 mmol) synthesized in step 1 dissolved in ethanol (10 mL) at room temperature was stirred overnight at 90 ℃. The reaction was then terminated by cooling the temperature to room temperature. A saturated aqueous ammonium chloride solution was poured into the reaction mixture, followed by extraction with methylene chloride. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; dichloromethane/methanol=0% to 10%) and concentrated to give the title compound (0.03 g, 4.083%) as a colorless oil.

[ Step 3]6- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -3-fluoro-2-pyridinyl ] methyl ] -5-oxo-1, 3, 4-oxadiazol-2-yl ] -3, 4-dihydro-1H-isoquinoline-2-carboxylic acid tert-butyl ester synthesis

To a solution of tert-butyl 6- (2-thio-3H-1, 3, 4-oxadiazol-5-yl) -3, 4-dihydro-1H-isoquinoline-2-carboxylate (100.00%, 0.550g,1.650 mmol) and potassium carbonate (100.00%, 0.229g,2.311 mmol) synthesized in step 2 in N, N-dimethylformamide (10 mL) was added 2- [6- (bromomethyl) -5-fluoro-3-pyridinyl ] -5- (difluoromethyl) -1,3, 4-oxadiazol (100.00%, 0.610g,1.980 mmol) dissolved at room temperature and stirred overnight at the same temperature. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; ethyl acetate/hexane=0% to 60%) and concentrated to obtain the title compound (0.3995 g,42.71% as yellow solid).

[ Step 4] Synthesis of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -3-fluoro-2-pyridinyl ] methyl ] -5- (1, 2,3, 4-tetrahydroisoquinolin-6-yl) -1,3, 4-oxadiazol-2-thione

A solution of 6- [4- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -3-fluoro-2-pyridinyl ] methyl ] -5-thio-1, 3, 4-oxadiazol-2-yl ] -3, 4-dihydro-1H-isoquinoline-2-carboxylic acid tert-butyl ester (100.00%, 0.3995 g,0.705 mmol) synthesized in step 3 and trifluoroacetic acid (100.00% solution, 0.539mL,7.040 mmol) in dichloromethane (5 mL) at room temperature was stirred overnight at the same temperature. The aqueous solution of N-sodium hydrogencarbonate was poured into the reaction mixture, followed by extraction with methylene chloride. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The resulting product was used without further purification (0.32 g,98.64% yellow oil).

[ Step 5] Synthesis of Compound 135

A solution of 3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -3-fluoro-2-pyridinyl ] methyl ] -5- (1, 2,3, 4-tetrahydroisoquinolin-6-yl) -1,3, 4-oxadiazol-2-thione (100.00%, 0.060g,0.130 mmol), formaldehyde (37.00% solution, 0.026mL,0.261 mmol) and N-ethyl-N-isopropyl-propan-2-amine (100.00% solution, 0.045mL,0.258 mmol) synthesized in step 4 was stirred at room temperature for 30 minutes, sodium triacetoxyborohydride (100.00%, 0.082g,0.389 mmol) was added, and stirring was continued at the same temperature for 18 hours. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; dichloromethane/methanol=0% to 10%) and concentrated to give the title compound (0.021 g,33.96% as a pale yellow solid).

¹H NMR(400MHz,CDCl₃)δ9.12(s,1H),8.15(dd,J＝9.0,1.8Hz,1H),7.79-7.76(m,2H),7.17(d,J＝8.0Hz,1H),6.96(t,J＝52.2Hz,1H),4.80(d,J＝1.6Hz,2H),3.65(s,2H),3.01(t,J＝5.8Hz,2H),2.76-2.73(m,2H),2.50(s,3H);LRMS(ES)m/z475.9(M⁺+1).

The compounds in table 21 below were synthesized according to the substantially same method as in example 135.

TABLE 21

EXAMPLE 69 Synthesis of Compound 69,3- [ [5- [5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl ] -2-pyridinyl ] methyl ] -5- (2-thienyl) -6H-1,3, 4-oxadiazin-2-one

[ Step 1] [ 2-oxo-2- (2-thienyl) ethyl ] acetate Synthesis

To a solution of 2-bromo-1- (2-thienyl) ethanone (100.00%, 0.500g,2.438 mmol) dissolved in N, N-dimethylformamide (10 mL) at room temperature was added potassium acetate (100.00%, 0.428 g,7.316 mmol) and potassium iodide (100.00%, 0.405g,2.440 mmol), and the mixture was stirred at the same temperature for 18 hours. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The resulting product was used without further purification (0.4475 g,99.078% yellow oil).

Synthesis of [ step 2] [ 2E) -2- (methoxycarbonylhydrazino) -2- (2-thienyl) ethyl ] acetate

To a solution of [ 2-oxo-2- (2-thienyl) ethyl ] acetate (100.00%, 0.445g,2.416 mmol) and hydrogen chloride (1.00M solution, 0.048mL,0.048 mmol) synthesized in step 1 dissolved in methanol (10 mL) at room temperature was added methyl hydrazinecarboxylate (100.00%, 0.239g,2.653 mmol), and stirred at the same temperature for 18 hours. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=0% to 50%) and concentrated to give the title compound (0.425 g,68.648% as a yellow solid).

[ Step 3] Synthesis of 5- (2-thienyl) -3, 6-dihydro-1, 3, 4-oxadiazin-2-one

A solution of [ (2E) -2- (methoxycarbonylhydrazono) -2- (2-thienyl) ethyl ] acetate (100.00%, 0.425g, 1.188 mmol) synthesized in step 2 and sodium ethoxide (about 20% ethanol solution, 20.00% solution, 0.962mL,2.500 mmol) dissolved in ethanol (10 mL) at room temperature was stirred at the same temperature for 30 minutes. A saturated aqueous ammonium chloride solution was poured into the reaction mixture, followed by extraction with methylene chloride. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=0% to 30%) and concentrated to give the title compound (0.2 g,66.192% as a yellow solid).

[ Step 4] Synthesis of Compound 69

A solution of 5- (2-thienyl) -3, 6-dihydro-1, 3, 4-oxadiazin-2-one (100.00%, 0.045g,0.247 mmol), 2- [6- (bromomethyl) -3-pyridyl ] -5- (difluoromethyl) -1,3, 4-oxadiazole (100.00%, 0.075g,0.259 mmol), potassium carbonate (100.00%, 0.037g,0.373 mmol) and potassium iodide (100.00%, 0.020g,0.120 mmol) synthesized in step 3 was dissolved in N, N-dimethylformamide (1 mL) at room temperature was stirred overnight at the same temperature. The reaction mixture was poured into water, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; ethyl acetate/hexane=0% to 60%) and concentrated to obtain the title compound (0.042 g,43.45%, pale yellow solid).

¹H NMR(400MHz,CDCl₃)δ9.32(d,J＝1.6Hz,1H),8.40(dd,J＝8.2,2.2Hz,1H),7.53(d,J＝8.4Hz,1H),7.47(dd,J＝5.2,1.2Hz,1H),7.25-7.24(m,1H),7.11-7.09(m,1H),6.96(t,J＝51.6Hz,1H),5.27(s,2H),5.25(s,2H);LRMS(ES)m/z 392.3(M⁺+1).

The compounds in table 22 below were synthesized according to the procedure substantially the same as in example 69.

TABLE 22

Example 142 Synthesis of Compound 142,3- ((5- (5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl) pyridin-2-yl) methyl) -5-phenyloxazol-2 (3H) -one

[ Step 1]6- (((tert-butoxycarbonyl) amino) methyl) nicotinic acid methyl ester Synthesis

To a solution of methyl 6- (aminomethyl) nicotinate (2.000 g,12.035 mmol) dissolved in methylene chloride (20 mL) at room temperature were added di-tert-butyl dicarbonate (3.152 g,14.442 mmol) and triethylamine (2.516 mL,18.053 mmol), and stirred at the same temperature for 18 hours. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 24g cartridge; ethyl acetate/hexane=0% to 40%) and concentrated to give the title compound (1.700 g,53.0% as a white solid).

[ Synthesis of methyl nicotinate by step 2]6- (((tert-butoxycarbonyl) (phenylethynyl) amino) methyl)

(Bromoethynyl) benzene (0.200 g,1.105 mmol) was dissolved in toluene (5 mL), and methyl 6- (((tert-butoxycarbonyl) amino) methyl) nicotinate synthesized in step 1 (0.353 g,1.326 mmol), copper (II) sulfate pentahydrate (0.055 g,0.221 mmol), potassium phosphate (0.563 g,2.651 mmol) and 1, 10-phenanthroline (0.080 g,0.442 mmol) were added at room temperature and stirred at 80℃for 36 hours. The reaction was then terminated by reducing the temperature to room temperature. The reaction mixture was filtered through a pad of celite to remove solids, and the solvent in the filtrate was removed under reduced pressure. The concentrate was then purified by column chromatography (SiO ₂, 12g cartridge; ethyl acetate/hexane=0% to 70%) and concentrated to give the title compound (0.110 g,27.2%, pale yellow solid).

[ Step 3]6 Synthesis of- ((2-oxo-5-phenyloxazol-3 (2H) -yl) methyl) nicotinic acid methyl ester

To a solution of methyl 6- (((tert-butoxycarbonyl) (phenylethynyl) amino) methyl) nicotinate (0.050 g,0.136 mmol) synthesized in step 2, dissolved in methylene chloride (0.5 mL) at room temperature was added silver bis (trifluoromethanesulfonyl) imide (0.003g, 0.0070 mmol), and stirred at the same temperature for 1 hour. A saturated aqueous ammonium chloride solution was poured into the reaction mixture, and extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; ethyl acetate/hexane=0% to 30%) and concentrated to give the title compound (0.030 g,70.8% as a yellow solid).

[ Step 4]6 Synthesis of- ((2-oxo-5-phenyloxazol-3 (2H) -yl) methyl) nicotinyl hydrazide

A solution of methyl 6- ((2-oxo-5-phenyloxazol-3 (2H) -yl) methyl) nicotinate (0.016 g,0.052 mmol) and hydrazine monohydrate (0.050 mL,1.031 mmol) synthesized in step 3 dissolved in ethanol (1 mL) at 80℃was stirred at the same temperature for 18 hours. The reaction was then terminated by cooling the temperature to room temperature. After removal of the solvent from the reaction mixture under reduced pressure, the resulting product was used without further purification (0.016 g,100.0%, white solid).

Step 5 Synthesis of Compound 142

To a solution of 6- ((2-oxo-5-phenyloxazol-3 (2H) -yl) methyl) nicotinoyl hydrazide (0.015 g,0.048 mmol) and triethylamine (0.040 mL,0.290 mmol) synthesized in step 4 dissolved in tetrahydrofuran (0.7 mL) at room temperature was added 2, 2-difluoroacetic anhydride (0.024 mL,0.193 mmol) and stirred at 80℃for 6 hours. The reaction was then terminated by cooling the temperature to room temperature. Saturated aqueous sodium bicarbonate solution was poured into the reaction mixture, followed by extraction with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; hexane/ethyl acetate=100% to 50%) and concentrated to give the title compound (0.008 g,44.7% as a white solid).

¹H NMR(400MHz,CD₃OD)δ9.28(s,1H),8.53(dd,J＝7.8,2.2Hz,1H),7.67(d,J＝8.4Hz,1H),7.56(d,J＝7.6Hz,2H),7.44-7.40(m,3H),7.33(t,J＝7.4Hz,1H),7.26(t,J＝51.4Hz,1H),7.26(t,J＝51.4Hz,1H),5.09(s,2H);LRMS(ES)m/z 371.2(M⁺+1).

The compounds in table 23 below were synthesized in substantially the same manner as in example 142.

TABLE 23

EXAMPLE 144 Synthesis of Compound 144,1- ((5- (5- (difluoromethyl) -1,3, 4-oxadiazol-2-yl) pyridin-2-yl) methyl) -3-methyl-4-phenyl-1, 3-dihydro-2H-imidazol-2-one

To a solution of 1-methyl-5-phenyl-1, 3-dihydro-2H-imidazol-2-one (0.050 g,0.287 mmol) and 2- (6- (bromomethyl) pyridin-3-yl) -5- (difluoromethyl) -1,3, 4-oxadiazole (0.100 g,0.345 mmol) dissolved in N, N-dimethylformamide (1 mL) at room temperature was added potassium carbonate (0.060 g,0.431 mmol) and potassium iodide (0.010g, 0.057 mmol) and stirred at 80℃for 18 hours. The reaction was then terminated by reducing the temperature to room temperature. Water was poured into the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO ₂, 4g cartridge; dichloromethane/methanol=100% to 80%) and concentrated to give the title compound (0.012 g,10.9%, white solid).

¹H NMR(400MHz,CDCl₃)δ8.18(d,J＝8.4Hz,2H),8.15(dd,J＝4.2,1.8Hz,1H),7.71(d,J＝8.0Hz,2H),7.62-7.57(m,2H),7.51-7.37(m,3H),6.95(t,J＝51.8Hz,1H),6.79(s,1H),5.66(s,2H),3.51(s,3H);LRMS(ES)m/z 384.2(M⁺+1).

Activity measurement and analysis protocol for the Compounds of the invention

Experimental example 1 confirmation of inhibition of HDAC enzyme Activity (in vitro)

The following experiments were performed to confirm HDAC6 selectivity of the compounds represented by formula I of the present invention by HDAC1 and HDAC6 enzyme activity inhibition assays.

HDAC enzymatic activity was determined using the HDAC fluorescence drug discovery kit (HDAC Fluorometric Drug Discovery Kit, BML-AK511,516) produced by enco LIFE SCIENCE. For the HDAC1 enzyme activity assay, human recombinant HDAC1 (BML-SE 456) was used as enzyme source, using "SIRT1 (BNL-KI 177) as substrate. Split-loading 5-fold diluted compound into 96-well plates, adding 0.3 μg enzyme and 10 μM substrate per well, reacting at 30deg.C for 60 min, addingDevelopment II (BML-KI 176) for 30 minutes to complete the reaction. Fluorescence values (Ex 360, em 460) were then measured using a multi-plate reader (Flexstation 3,Molecular Device). HDAC6 enzyme was assayed using the same protocol as the HDAC1 enzyme activity assay using human recombinant HDAC6 (382180) from Calbiochem. For the final results, the value of each IC ₅₀ was calculated using the GRAPHPAD PRISM 4.0 program. The results are shown in Table 24 below.

TABLE 24

As shown in table 24 above, from the HDAC1 and HDAC6 activity inhibition test results, the 1,3, 4-oxadiazole derivative compound of the present invention, its stereoisomer or its pharmaceutically acceptable salt, exhibits about 185 to about 3497 times excellent selective HDAC6 inhibitory activity.

Claims (13)

1. A 1,3,4-oxadiazole derivative compound represented by the following chemical formula I, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof: [Chemical Formula I] In the above chemical formula I, _R1 is _-C1-4 haloalkyl; _X1 to _X4 are each independently CR _X or N; _RX is -H, _-C1-4alkyl , _{-C1-4haloalkyl} or -halogen; Y is CR _Y or N; _RY is -H or -C _1-4 alkyl; Z is NR _Z , O or S; R _Z is -H or -C _1-4 alkyl; W is O or S; m is 0 or 1; Ring V is aryl, heteroaryl or hydroheteroaryl, wherein at least one H in the aryl, heteroaryl or hydroheteroaryl ring may be substituted by -C _1-4 alkyl, -C _1-4 aminoalkyl, -C _1-4 hydroxyalkyl, -C _1-4 haloalkyl, -halogen, -(CH ₂ )n-cycloalkyl, -(CH ₂ )n-heterocyclyl or -(CH ₂ )n-heteroaryl, wherein at least one H in the -(CH ₂ )n-cycloalkyl, -(CH ₂ )n-heterocyclyl or -(CH ₂ )n-heteroaryl ring may be substituted by -C _1-4 alkyl, -C _1-4 haloalkyl, -halogen, cycloalkyl or heterocyclyl (wherein at least one H in the cycloalkyl or heterocyclyl ring may be substituted by -C _1-4 alkyl); and n is 0, 1 or 2. 2. The 1,3,4-oxadiazole derivative compound according to claim 1, its stereoisomer or a pharmaceutically acceptable salt thereof, wherein _R1 is _-C1-4 haloalkyl; X ₁ is N; _X2 to _X4 are each independently CR _x ; _RX is -H or -halogen; Y is CR _Y or N; _RY is -H; Z is NR _Z , O or S; R _Z is -C _1-4 alkyl; W is O or S; m is 0 or 1; Ring V is aryl, heteroaryl or hydroheteroaryl, wherein at least one H on the aryl, heteroaryl or hydroheteroaryl ring may be substituted by -C _1-4 alkyl, -C _1-4 aminoalkyl, -halogen, -(CH ₂ )n-cycloalkyl, -(CH ₂ )n-heterocyclyl or -(CH ₂ )n-heteroaryl, wherein at least one H on the -(CH ₂ )n-cycloalkyl, -(CH ₂ )n-heterocyclyl or -(CH ₂ )n-heteroaryl ring may be substituted by -C _1-4 alkyl, -halogen, cycloalkyl or heterocyclyl (wherein at least one H on the cycloalkyl or heterocyclyl ring may be substituted by -C _1-4 alkyl); and n is 0 or 1. 3. The 1,3,4-oxadiazole derivative compound according to claim 1, its stereoisomer or a pharmaceutically acceptable salt thereof, wherein R ₁ is -CF ₂ H or -CF ₃ . 4. The 1,3,4-oxadiazole derivative compound according to claim 1, its stereoisomer or a pharmaceutically acceptable salt thereof, wherein _X1 is N; and _X2 to _X4 are each independently CH or CF. 5. The 1,3,4-oxadiazole derivative compound according to claim 1, its stereoisomer or a pharmaceutically acceptable salt thereof, wherein Y is CH or N; Z is NC _1-4 alkyl, O or S; W is O or S; and m is 0 or 1. 6. The 1,3,4-oxadiazole derivative compound according to claim 1, its stereoisomer or a pharmaceutically acceptable salt thereof, wherein Ring V is phenyl, 5-10 membered heteroaryl or 9-10 membered hydrogen heteroaryl, wherein at least one H in the phenyl, 5-10 membered heteroaryl or 9-10 membered hydrogen heteroaryl ring may be substituted by -C _1-4 alkyl, -C _1-4 aminoalkyl, -halogen, -(CH ₂ )n-cycloalkyl, -(CH ₂ )n-heterocyclyl or -(CH ₂ )n-heteroaryl, wherein at least one H in the -(CH ₂ )n-cycloalkyl, -(CH ₂ )n-heterocyclyl or -(CH ₂ )n-heteroaryl ring may be substituted by -C _1-4 alkyl, -halogen, 4-6 membered cycloalkyl or 4-6 membered heterocyclyl (wherein at least one H in the 4-6 membered cycloalkyl or 4-6 membered heterocyclyl ring may be substituted by -C _1-4 alkyl); and n is 0 or 1. 7. The 1,3,4-oxadiazole derivative compound according to claim 1, its stereoisomer or a pharmaceutically acceptable salt thereof, wherein The compound represented by the chemical formula I is any one selected from the following compounds: 8. A pharmaceutical composition for preventing or treating a disease mediated by histone deacetylase 6, comprising: The compound represented by Chemical Formula I according to any one of claims 1 to 7, its stereoisomer or a pharmaceutically acceptable salt thereof as an active ingredient. 9. The pharmaceutical composition for preventing or treating a disease mediated by histone deacetylase 6 according to claim 8, wherein The diseases mediated by histone deacetylase 6 are infectious diseases; tumors; endocrine, nutritional and metabolic diseases; mental and behavioral disorders; nervous system diseases; eye and eye appendage diseases; circulatory system diseases; respiratory system diseases; digestive system diseases; skin and subcutaneous tissue diseases; musculoskeletal and connective tissue diseases; or congenital malformations, mutations and chromosomal abnormalities. 10. The pharmaceutical composition for preventing or treating a disease mediated by histone deacetylase 6 according to claim 9, wherein The endocrine, nutritional and metabolic disease is Wilson's disease, amyloidosis or diabetes, The mental and behavioral disorders are depression or Rett syndrome, The nervous system disease is atrophy of the central nervous system, neurodegenerative diseases, movement disorders, neuropathy, motor neuron disease and demyelinating disease of the central nervous system, The eye and ocular adnexal disease is uveitis, The skin and subcutaneous tissue disease is psoriasis, The musculoskeletal and connective tissue disease is rheumatoid arthritis, osteoarthritis or systemic lupus erythematosus (SLE), The congenital malformation, variation and chromosomal abnormality is autosomal dominant polycystic kidney disease, The infectious disease is prion disease, The tumor is a benign tumor or a malignant tumor, The circulatory system disease is atrial fibrillation or stroke, The respiratory disease is asthma, and The digestive system disease is alcoholic liver disease, inflammatory bowel disease, Crohn's disease or ulcerative bowel disease. 11. A method for preventing or treating a disease mediated by histone deacetylase 6, comprising administering a therapeutically effective amount of a compound represented by Chemical Formula I according to any one of claims 1 to 7, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof as an active ingredient. 12. Use of a compound represented by Chemical Formula I according to any one of claims 1 to 7, a stereoisomer thereof or a pharmaceutically acceptable salt thereof in the preparation of a medicament for preventing or treating a disease mediated by histone deacetylase 6. 13. Use of the compound represented by Chemical Formula I according to any one of claims 1 to 7, its stereoisomer or a pharmaceutically acceptable salt thereof for preventing or treating a disease mediated by histone deacetylase 6.