1,3,4-Oxadiazole Derivative Compounds as Histone Deacetylase 6 Inhibitors and Their Use

Abstract

The present invention relates to novel compounds having histone deacetylase 6 (HDAC6) inhibitory activity, a method for producing the same, and uses thereof. The novel compound according to the present invention, its stereoisomer, or a pharmaceutically acceptable salt thereof has histone deacetylase 6 (HDAC6) inhibitory activity and is effective in preventing or treating HDAC6-associated diseases, including cancer, inflammatory diseases, autoimmune diseases, neurological or neurodegenerative diseases.

Description

[Technical Field]

[0001] The present invention relates to a 1,3,4-oxadiazole derivative compound with a novel structure that has histone deacetylase 6 (HDAC6) inhibitory activity, a method for producing the same, and use thereof. [Background technology]

[0002] Post-translational modifications such as acetylation in cells are crucial regulatory modules at the heart of biological processes and are tightly controlled by numerous enzymes. Histones are central proteins that make up chromatin, acting as the axis around which DNA winds and aids in DNA condensation. The balance between histone acetylation and deacetylation also plays a crucial role in gene expression.

[0003] Histone deacetylases (HDACs) are enzymes that remove acetyl groups from lysine residues in histone proteins, which make up chromatin. They are known to be involved in gene silencing and induce cell cycle arrest, angiogenesis suppression, immunomodulation, and cell death (Hassig et al., Curr. Opin. Chem. Biol. 1997, 1, 300-308). Furthermore, inhibition of HDAC enzyme function has been reported to reduce the activity of cancer cell survival-related factors and activate cancer cell death-related factors in vivo, thereby inducing cancer cell self-destruction (Warrell et al., J. Natl. Cancer Inst. 1998, 90, 1621-1625).

[0004] In humans, 18 HDACs are known, classified into four classes based on their homology with yeast HDACs. Eleven HDACs that use zinc as a cofactor are divided into three 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 (HDAC 11). Seven HDACs in Class III (SIRTs 1-7) use NAD+ as a cofactor instead of zinc (Bolden et al., Nat. Rev. Drug Discov. 2006, 5(9), 769-784).

[0005] Although various HDAC inhibitors are in preclinical or clinical development, only nonselective HDAC inhibitors have been approved as anticancer drugs. Vorinostat (SAHA) and romidepsin (FK228) are approved for the treatment of cutaneous T-cell lymphoma, and panobinostat (LBH-589) has been approved for the treatment of multiple myeloma. However, nonselective HDAC inhibitors generally cause side effects such as fatigue and nausea at high doses (Piekarz et al., Pharmaceuticals 2010, 3, 2751-2767). These side effects have been reported to be caused by class I HDAC inhibition, and these side effects have limited the development of non-selective HDAC inhibitors in fields other than anticancer drugs (Witt et al., Cancer Letters 277, (2009), 8-21).

[0006] On the other hand, selective class II HDAC inhibition has been reported to be free of the toxicity seen in class I HDAC inhibition. If selective HDAC inhibitors are developed, they may be able to overcome the side effects, such as toxicity, caused by non-selective HDAC inhibition. Selective HDAC inhibitors may therefore be developed as effective therapeutic agents for a variety of diseases (Matthias et al., Mol. Cell. Biol. 2008, 28, 1688-1701).

[0007] HDAC6, a Class IIb HDAC, is primarily present in the cytoplasm and is known to be involved in the deacetylation of numerous non-histone substrates, including tubulin (HSP90, cortactin, etc.) (Yao et al., Mol. Cell 2005, 18, 601-607). HDAC6 has two catalytic domains, and a C-terminal zinc finger domain that can bind to ubiquitinated proteins. HDAC6 has many non-histone protein substrates and is therefore known to play important roles in various diseases, including cancer, inflammatory diseases, autoimmune diseases, neurological diseases, and neurodegenerative disorders (Santo et al., Blood 2012 119, 2579-2589; Vishwakarma et al., International Immunopharmacology 2013, 16, 72-78; Hu et al., J. Neurol. Sci. 2011, 304, 1-8).

[0008] The common structural features of various HDAC inhibitors are a cap group, a linker group, and a zinc-binding group (ZBG), as shown in the following structure of vorinostat. Many researchers have investigated the enzyme inhibitory activity and selectivity through structural modifications of the cap group and linker group. Among these, the zinc-binding group is known to play a more important role in enzyme inhibitory activity and selectivity (Wiest et al., J. Org. Chem. 2013 78:5051-5055; Methot et al., Bioorg. Med. Chem. Lett. 2008, 18, 973-978). [ka]

[0009] Most of these zinc-binding groups are hydroxamic acids or benzamides. Hydroxamic acid derivatives exhibit potent HDAC inhibitory effects, but suffer from low bioavailability and severe off-target activity. Benzamides, which contain aniline, have the potential to generate toxic metabolites in vivo (Woster et al., Med. Chem. Commun. 2015, online publication).

[0010] Therefore, unlike non-selective inhibitors that have side effects, the development of selective HDAC6 inhibitors with zinc-binding groups that are free of side effects and have improved bioavailability is currently required for the treatment of cancer, inflammatory diseases, autoimmune diseases, neurological diseases, and neurodegenerative disorders. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] WO2011 / 091213:ACY-1215 [Patent Document 2] WO2011 / 011186:Tubastatin [Patent Document 3] WO2013 / 052110:Sloan-K [Patent Document 4] WO2013 / 041407:Cellzome [Patent Document 5] WO2013 / 134467:Kozi [Patent Document 6] WO2013 / 008162:Novartis [Patent Document 7] WO2013 / 080120:Novartis [Patent Document 8] WO2013 / 066835:Tempero [Patent Document 9] WO2013 / 066838:Tempero [Patent Document 10] WO2013 / 066833:Tempero [Patent Document 11] WO2013 / 066839:Tempero Summary of the Invention [Problem to be solved by the invention]

[0012] An object of the present invention is to provide a compound, a stereoisomer thereof or a pharmaceutically acceptable salt thereof, which has selective histone deacetylase 6 (HDAC6) inhibitory activity.

[0013] Another object of the present invention is to provide a pharmaceutical composition comprising a compound having selective HDAC6 inhibitory activity, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof.

[0014] It is still another object of the present invention to provide a method for producing the same.

[0015] It is yet another object of the present invention to provide a pharmaceutical composition for preventing or treating diseases associated with HDAC6 activity.

[0016] Yet another object of the present invention is to provide its use for the manufacture of a medicament for the prevention or treatment of diseases associated with HDAC6 activity.

[0017] It is yet another object of the present invention to provide a method for preventing or treating diseases associated with HDAC6 activity, which comprises administering a therapeutically effective amount of said compound.

[0018] It is yet another object of the present invention to provide preventive or therapeutic uses for diseases associated with HDAC6 activity. [Means for solving the problem]

[0019] The present inventors have discovered oxadiazole derivative compounds having histone deacetylase 6 (HDAC6) inhibitory activity, and have accomplished the present invention by using these compounds to inhibit or treat diseases associated with HDAC6 activity.

[0020] This will be described in detail below. All combinations of the various elements disclosed in the present invention fall within the scope of the present invention. Furthermore, the following specific descriptions should not be construed as limiting the scope of the present invention.

[0021] 1,3,4-Oxadiazole oxadiazolone derivative compounds In accordance with the above object, the present invention provides a 1,3,4-oxadiazole derivative compound represented by the following formula I, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof: [Chemical I] [ka]

[0022] In the formula I, R1 is -C 1-4 is haloalkyl; X1 to X4 are each independently X or N; R X -H, -C 1-4 Alkyl, -C 1-4 haloalkyl, or -halo; Y is CR Y or N; R Y is -H or -C 1-4 is alkyl; Z is NR Z , O, or S; R Z is -H or -C 1-4 is alkyl; W is O or S; m is 0 or 1; Ring V is an aryl, heteroaryl, or hydroheteroaryl {wherein one or more H in said aryl, heteroaryl, or hydroheteroaryl ring is —C 1-4 Alkyl, -C 1-4 Aminoalkyl, -C 1-4 Hydroxyalkyl, -C 1-4 and optionally substituted with haloalkyl, -halo, -(CH2)n-cycloalkyl, -(CH2)n-heterocycloalkyl, or -(CH2)n-heteroaryl, wherein one or more H on said -(CH2)n-cycloalkyl, -(CH2)n-heterocycloalkyl, or -(CH2)n-heteroaryl ring is replaced by -C 1-4 Alkyl, -C 1-4 and optionally substituted with haloalkyl, -halo, cycloalkyl, or heterocycloalkyl (wherein one or more H in said cycloalkyl or heterocycloalkyl ring is replaced by -C 1-4 and n is 0, 1, or 2.

[0023] According to an embodiment of the present invention, the compounds of formula I of the present invention may range from: R1 is -C 1-4 is haloalkyl; X1 is N; X2 to X4 are each independently X and; R X is -H or -halo; Y is CR Y or N; R Y is -H; Z is NR Z , O, or S; R Z -C 1-4 is alkyl; W is O or S; m is 0 or 1; Ring V is an aryl, heteroaryl, or hydroheteroaryl {wherein one or more H in said aryl, heteroaryl, or hydroheteroaryl ring is —C 1-4 Alkyl, -C 1-4 and optionally substituted with aminoalkyl, -halo, -(CH2)n-cycloalkyl, -(CH2)n-heterocycloalkyl, or -(CH2)n-heteroaryl, wherein one or more H on said -(CH2)n-cycloalkyl, -(CH2)n-heterocycloalkyl, or -(CH2)n-heteroaryl ring is replaced by -C 1-4 and optionally substituted with alkyl, -halo, cycloalkyl, or heterocycloalkyl (wherein one or more H in said cycloalkyl or heterocycloalkyl ring is replaced by -C 1-4 and n is 0 or 1.

[0024] Also, according to an embodiment of the present invention, the compounds of formula I of the present invention may be in the following ranges: R1 is -CF2H or -CF3.

[0025] Also, according to an embodiment of the present invention, the compounds of formula I of the present invention may be in the following ranges: X1 is N; and X2 to X4 are each independently CH or CF.

[0026] Also, according to an embodiment of the present invention, the compounds of formula I of the present invention may be in the following ranges: 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.

[0027] Also, according to an embodiment of the present invention, the compounds of formula I of the present invention may be in the following ranges: Ring V is phenyl, a 5- to 10-membered heteroaryl, or a 9- to 10-membered hydroheteroaryl, wherein one or more H in said phenyl, 5- to 10-membered heteroaryl, or 9- to 10-membered hydroheteroaryl ring is selected from the group consisting of -C 1-4 Alkyl, -C 1-4 and optionally substituted with aminoalkyl, -halo, -(CH2)n-cycloalkyl, -(CH2)n-heterocycloalkyl, or -(CH2)n-heteroaryl, wherein one or more H on said -(CH2)n-cycloalkyl, -(CH2)n-heterocycloalkyl, or -(CH2)n-heteroaryl ring is replaced by -C 1-4 and optionally substituted with alkyl, -halo, 4- to 6-membered cycloalkyl, or 4- to 6-membered heterocycloalkyl (wherein one or more H in the 4- to 6-membered cycloalkyl or 4- to 6-membered heterocycloalkyl ring is -C 1-4 and n is 0 or 1.

[0028] Furthermore, according to an embodiment of the present invention, specific compounds represented by formula I of the present invention are as shown in Table 1 below:

[0029] [Table 1] [Table 2] [Table 3] [Table 4] [Table 5] [Table 6] [Table 7]

[0030] In the present invention, unless otherwise specified, "alkyl" can mean a straight or branched chain, acyclic, cyclic or a saturated hydrocarbon having these combined thereto. For example, "C 1-4 "Alkyl" may refer to an alkyl containing 1 to 4 carbon atoms. Non-cyclic alkyl may include, by way of example only, methyl, ethyl, n-propyl, n-butyl, isopropyl, sec-butyl, isobutyl, or tert-butyl, and the like, but is not limited thereto. Cyclic alkyl may be used interchangeably herein with "cycloalkyl," and may include, by way of example only, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, or cyclooctyl, and the like, but is not limited thereto.

[0031] In the present invention, "alkoxy" can refer to an alkyl ether group, -(O-alkyl), where alkyl is as defined above. For example, "C 1-4 "Alkoxy" is C 1-4 Alkoxy containing alkyl, i.e., -(OC 1-4Alkoxy can refer to alkoxy groups, and by way of example, alkoxy can include, but is not limited to, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, or tert-butoxy, and the like.

[0032] In the present invention, "halo" may be F, Cl, Br, or I.

[0033] As used herein, "haloalkyl" refers to a straight or branched chain alkyl (hydrocarbon) having one or more carbon atoms substituted with one or more halo groups, as defined herein. Examples of haloalkyl include, but are not limited to, methyl, ethyl, propyl, isopropyl, isobutyl, or n-butyl, each independently substituted with one or more halogen atoms, such as F, Cl, Br, or I.

[0034] In the present invention, "hydroxyalkyl" can refer to a straight or branched chain alkyl (hydrocarbon) having a carbon atom substituted with -OH. Examples of hydroxyalkyl include, but are not limited to, methyl, ethyl, propyl, isopropyl, isobutyl, or n-butyl, each independently substituted with one or more hydroxy groups.

[0035] As used herein, "aminoalkyl" can refer to a straight or branched chain alkyl (hydrocarbon) having a carbon atom substituted with amino-(NR'R"), where R' and R" are each independently hydrogen, and C 1-4 alkyl, wherein each of said selected R' and R'' can be independently substituted or unsubstituted.

[0036] In the present invention, "heterocycloalkyl" refers to a ring containing 1 to 5 heteroatoms selected from N, O, and S as ring-forming atoms, and may be saturated or partially unsaturated. When unsaturated, it can be referred to as a heterocycloalkene. Unless otherwise specified, heterocycloalkyl may be a monocyclic ring or a polycyclic ring such as a spiro ring, a bridged ring, or a fused ring. Furthermore, "heterocycloalkyl of 3 to 12 atoms" refers to a heterocycloalkyl containing 3 to 12 ring-forming atoms. Examples of heterocycloalkyl include pyrrolidine, piperidine, imidazolidine, pyrazolidine, butyrolactam, valerolactam, imidazolidinone, hydantoin, dioxolane, phthalimide, piperidine, pyrimidine-2,4(1H,3H)-dione, 1,4-dioxane, morpholine, thiomorpholine, thiomorpholine-S-oxide, thiazolinone ... These compounds may include, but are not limited to, morpholine-S,S-oxide, piperazine, pyran, pyridone, 3-pyrroline, thiopyran, pyrone, 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.

[0037] In the present invention, "arene" may refer to an aromatic hydrocarbon ring. The arene may be a monocyclic arene or a polycyclic arene. The number of ring carbon atoms of the arene may be 5 to 30, 5 to 20, or 5 to 15. Examples of arenes include, but are not limited to, benzene, naphthalene, fluorene, anthracene, phenanthrene, bibenzene, terbenzene, quaterbenzene, quinquephenylyl, sexibenzene, triphenylene, pyrene, benzofluoranthene, and chrysene. In this specification, a residue obtained by removing one hydrogen atom from the above-mentioned "arene" is referred to as "aryl."

[0038] In the present invention, a "heteroarene" may be a ring containing one or more heteroatoms selected from O, N, P, Si, and S. The number of ring carbon atoms in a heteroarene may be 2 or more and 30 or less, or 2 or more and 20 or less. A heteroarene may be a monocyclic heteroarene or a polycyclic heteroarene. A polycyclic heteroarene may have, for example, a two- or three-ring structure. Examples of heteroarenes include thiophene, purine, pyrrole, pyrazole, imidazole, thiazole, oxazole, isothiazole, oxadiazole, triazole, pyridine, bipyridyl, triazine, acridyl, pyridazine, pyrazine, quinoline, quinazoline, quinoxaline, phenoxazine, phthalazine, pyrimidine, pyridopyrimidine, pyridopyrazine, pyrazinopyrazine, isoquinoline, indole, carbazole, imidazopyridazine, imidazopyridine, imidazopyrimidine, and pyrazolopyrimidine. Examples of heteroarene include, but are not limited to, imidazopyrazine or pyrazolopyridine, N-arylcarbazole, N-heteroarylcarbazole, N-alkylcarbazole, benzoxazole, benzimidazole, benzothiazole, benzocarbazole, benzothiophene, dibenzothiophene, thienothiophene, benzofuran, phenanthroline, isoxazole, oxadiazole, thiadiazole, benzothiazole, tetrazole, phenothiazine, dibenzosilole, and dibenzofuran. In one embodiment of the present invention, the heteroarene may also include a bicyclic heterocyclo-arene, which includes an arene ring fused to a heterocycloalkyl ring or a heteroarene fused to a cycloalkyl ring. In this specification, a residue obtained by removing one hydrogen atom from the "heteroarene" is referred to as a "heteroaryl."

[0039] The compounds of Formula I of the present invention may contain one or more asymmetric carbon atoms and may therefore exist as racemates, racemic mixtures, single enantiomers, diastereoisomeric mixtures, and individual diastereomers. Such stereoisomers can be separated by conventional techniques, e.g., by resolution of the compounds of Formula I, such as by column chromatography or HPLC. Alternatively, individual stereoisomers of the compounds of Formula I can be stereospecifically synthesized using optically pure starting materials and / or reagents of known sequence.

[0040] In the present invention, the term "enantiomer" means a compound of the present invention or a salt thereof that has the same chemical or molecular formula but different spatial arrangement. Each such enantiomer and mixtures thereof are also included within the scope of the present invention. Unless otherwise specified, a solid bond (-) connected to an asymmetric carbon atom is replaced by a solid wedge bond that indicates the absolute configuration of the stereocenter. [ka] or dashed wedge bond [ka] may include:

[0041] The compound of Chemical Formula 1 of the present invention can exist in the form of a "pharmaceutically acceptable salt." As the salt, an acid addition salt formed with a pharmaceutically acceptable free acid is useful. The term "pharmaceutically acceptable salt" as used herein refers to any and all organic or inorganic acid addition salts of the compound, which have a relatively non-toxic and harmless effective concentration in patients, and the side effects attributable to the salt do not reduce the beneficial efficacy of the compound represented by Chemical Formula 1.

[0042] Acid addition salts are prepared by conventional methods, for example, by dissolving the compound in an excess amount of aqueous acid and precipitating the salt with a water-miscible organic solvent such as methanol, ethanol, acetone, or acetonitrile. Equal molar amounts of the compound and the acid or alcohol in water are heated, and the mixture can then be evaporated to dryness or the precipitated salt can be filtered off with suction.

[0043] In this case, the free acid may be an organic acid or an inorganic acid, and examples of the inorganic acid include hydrochloric acid, phosphoric acid, sulfuric acid, and nitric acid. Examples of the organic acid 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, carboxylic acid, vanillic acid, and hydroiodic acid. However, the organic and inorganic acids are not limited to these.

[0044] Pharmaceutically acceptable metal salts can also be prepared using a base. Alkali metal salts or alkaline earth metal salts can be obtained, for example, by dissolving a compound in an excess amount of alkali metal hydroxide or alkaline earth metal hydroxide solution, filtering the undissolved compound salt, and evaporating and drying the filtrate. In this case, sodium, potassium, or calcium salts are particularly suitable for pharmaceutical purposes, but are not limited to these. Corresponding silver salts can also be obtained by reacting an alkali metal or alkaline earth metal salt with an appropriate silver salt (e.g., silver nitrate).

[0045] Unless otherwise specified, pharmaceutically acceptable salts of the present invention include salts of acidic or basic groups that may be present in the compounds of Formula 1. For example, pharmaceutically acceptable salts may include sodium, calcium, and potassium salts of hydroxy groups, and other pharmaceutically acceptable salts of amino groups include hydrobromide, sulfate, hydrogen sulfate, phosphate, hydrogen phosphate, dihydrogen phosphate, acetate, succinate, citrate, tartrate, lactate, mandelate, methanesulfonate (mesylate), and p-toluenesulfonate (tosylate) salts, which may be prepared by salt preparation methods known in the art.

[0046] Method for producing 1,3,4-oxadiazole derivative compounds The present invention provides a method for producing a 1,3,4-oxadiazole derivative compound represented by the following formula I, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof. [Chemical I] [ka]

[0047] The formula I is as defined above.

[0048] In the present invention, preferred methods for producing the oxadiazole derivative compound represented by Formula I, its stereoisomer, or a pharmaceutically acceptable salt thereof are shown in the following [Reaction Scheme 1] to [Reaction Scheme 8], and these methods also include modifications that would be obvious to a person skilled in the art.

[0049] [Reaction Scheme 1] [ka]

[0050] According to Reaction Scheme 1, compound 1-1 is added with hydrazine to produce compound 1-2, which is then reacted with trifluoroacetic anhydride or difluoroacetic anhydride to produce compound 1-3, which is then brominated to produce compound 1-4, which is the Zn-Binder moiety of HDAC6 inhibitors and is used as an intermediate in the synthesis of all compounds.

[0051] [Reaction Scheme 2] [ka]

[0052] According to Reaction Scheme 2, compound 2-1 is prepared using hydrazine to produce compound 2-2, and then 1,3,4-oxadiazol-2(3H)-one and potassium ethylxanthate are used with CDI to produce 1,3,4-oxadiazol-2(3H)-thione compound 2-4. Alternatively, Lawesson's reagent can be added to compound 2-2 to produce compound 2-3, and then 1,3,4-thiadiazol-2(3H)-one compound 2-4 can be produced using CDI. Compound 2-5 is produced by a substitution reaction between compound 2-4 and compound 1-4. Compound 2-5 prepared by Reaction Scheme 2 may be 1, 5, 15, 16, 17, 18, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 59, 60, 61, 62, etc.

[0053] [Reaction Scheme 3] [ka]

[0054] In Reaction Scheme 3, compound 3-1 having an aldehyde structure is subjected to reductive amination to produce compound 3-2, and then compound 3-3 is prepared using hydrazine. Compound 3-3 is then prepared using CDI to produce 1,3,4-oxadiazol-2(3H)-one compound 3-4. Compound 3-5 can then be prepared by a substitution reaction with compound 1-4. Examples of compound 3-5 prepared by Reaction Scheme 3 include compounds 2 and 4.

[0055] [Reaction Scheme 3-1] [ka]

[0056] In Reaction Scheme 3-1, compound 3-1 is converted to dioxolane compound 3-1-1, which protects the aldehyde structure, using ethylene glycol, and then converted to compound 3-1-2 using hydrazine. Then, using CDI, 1,3,4-oxadiazol-2(3H)-one and potassium ethylxanthate, 1,3,4-oxadiazol-2(3H)-thione compound 3-1-3 is produced. Compound 3-1-4 is then converted to compound 1-4 via a substitution reaction. The dioxolane aldehyde protecting group is then removed using iron(III) chloride hexahydrate to produce compound 3-1-5. Compound 3-5 can then be produced by a reductive amination reaction. Examples of compound 3-5 produced by Reaction Scheme 3-1 include 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, and 134.

[0057] [Reaction Scheme 3-2] [ka]

[0058] In Reaction Scheme 3-2, compound 3-1 having an aldehyde structure is subjected to reductive amination to produce compound 3-2-1. Compound 3-2-2 is then prepared using hydrazine, followed by CDI and 1,3,4-oxadiazol-2(3H)-one and potassium ethylxanthate to produce 1,3,4-oxadiazol-2(3H)-thione compound 3-2-4. Compound 3-2-2 is then prepared using Lawesson's reagent to produce compound 3-2-3, followed by CDI and 1,3,4-thiadiazol-2(3H)-one compound 3-2-4. Compound 3-2-4 is then subjected to a substitution reaction with compound 1-4 to produce compound 3-2-5. The amine protecting group is removed to produce compound 3-2-6, which is then subjected to reductive amination to produce compound 3-2-7. Examples of the compound 3-2-7 produced in the above reaction scheme 3-2 include compounds 63, 64, 65, 66, 67, 68, 77, 78, 79, and 83.

[0059] [Reaction Scheme 4] [ka]

[0060] In Reaction Scheme 4, compound 4-2 is prepared from halogen-containing ester compound 4-1 by a Suzuki-C coupling (CC) reaction, followed by a reduction reaction to prepare compound 4-3. Compound 4-1 is then subjected to a Buchwald-C coupling and substitution reaction to prepare compound 4-3. Compound 4-4 is then prepared using hydrazine, and 1,3,4-oxadiazol-2(3H)-one and potassium ethylxanthate are then used with CDI to prepare 1,3,4-oxadiazol-2(3H)-thione compound 4-6. Compound 4-5 is then prepared from compound 4-4 using Lawesson's reagent, and then 1,3,4-thiadiazol-2(3H)-one compound 4-6 is then prepared using CDI. Compound 4-7 is then prepared by a substitution reaction with compound 1-4, and the amine protecting group is removed to prepare compound 4-8, which includes compounds 20, 23, and 36. Compound 4-9 can also be produced by a reductive amination reaction. Examples of Compound 4-9 produced by Reaction Scheme 4 include Compounds 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, and 127.

[0061] Alternatively, compound 4-8 prepared by Reaction Scheme 4 may be subjected to reductive amination to prepare compound 4-10, followed by removal of the amine protecting group to prepare compound 4-11, which may then be subjected to reductive amination to prepare compound 4-12. Examples of compound 4-12 include compounds 27 and 28.

[0062] [Reaction Scheme 4-1] [ka]

[0063] In the reaction scheme 4-1, hydrazine is used to prepare compound 4-2 from ester compound 4-1 containing a halogen atom, and CDI is used to prepare 1,3,4-oxadiazol-2(3H)-one compound 4-3. Compound 4-4 is then prepared by a substitution reaction with compound 1-4, and compound 4-9 is prepared by an amine substitution reaction. The compounds prepared in the reaction scheme 4-1 may be compounds 6, 7, etc.

[0064] [Reaction Scheme 5] [ka]

[0065] In Reaction Scheme 5, compound 5-1 containing an amine is alkylated with an amine protecting group to produce compound 5-2, and then compound 5-3 is prepared using hydrazine. Compound 5-3 is then prepared using CDI, 1,3,4-oxadiazol-2(3H)-one, and potassium ethylxanthate to produce 1,3,4-oxadiazol-2(3H)-thione compound 5-4. Compound 5-5 is then prepared by a substitution reaction with compound 1-4. Examples of compound 5-5 prepared by Reaction Scheme 5 include compounds 19, 31, and 32.

[0066] Furthermore, the amine protecting group of compound 5-5 prepared by the above reaction formula 5 can be removed to prepare compound 5-6, and examples of compound 5-6 include compounds 3, 11, 33, 34, and 35.

[0067] Then, compound 5-7 is produced by reductive amination. Compounds 5-7 produced by Reaction Scheme 5 include compounds 12, 13, 14, 135, 136, 137, 138, 139, 140, and 141.

[0068] [Reaction Scheme 6] [ka]

[0069] In Reaction Scheme 6, bromo compound 6-1 is substituted to produce acetate compound 6-2, which is then substituted to produce hydrazine carboxylate compound 6-3. Then, sodium ethylate is used to produce 1,3,4-oxadiazin-2-one compound 6-4, which is then substituted with compound 1-4 to produce compound 6-5. Compounds 6-5 produced by Reaction Scheme 6 include compounds 69, 70, 71, 72, 73, and 74.

[0070] [Reaction Scheme 7] [ka]

[0071] In Reaction Scheme 7, compound 7-1 is protected with an amine-protecting group to produce compound 7-2, which is then subjected to a substitution reaction with compound 7-3 to produce triple-bond compound 7-4. Then, bis(trifluoromethanesulfonyl)imide silver is used to produce oxazol-2(3H)-one compound 7-5. Compound 7-6 is then prepared using hydrazine, which is then reacted with trifluoroacetic anhydride or difluoroacetic anhydride to produce compound 7-7. Compounds prepared in Reaction Scheme 7 may include 142, 143, etc.

[0072] [Reaction Scheme 8] [ka]

[0073] In the reaction scheme 8, the imidazol-2-one compound 8-1 can be substituted with the compound 1-4 to produce the compound 8-2. The compound produced in the reaction scheme 8 can be 144 or the like.

[0074] Use of 1,3,4-oxadiazole derivative compounds The present invention provides the use of a compound represented by the following formula I, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof: [Chemical I] [ka]

[0075] The formula I is as defined above.

[0076] According to one embodiment of the present invention, there is provided a pharmaceutical composition comprising, as an active ingredient, a compound represented by formula I, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof.

[0077] In addition, according to one embodiment of the present invention, there is provided a pharmaceutical composition for preventing or treating diseases associated with histone deacetylase 6 activity, comprising, as an active ingredient, a compound represented by formula I, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof. The pharmaceutical composition of the present invention selectively inhibits histone deacetylase 6, thereby exhibiting significant effects in preventing or treating diseases associated with histone deacetylase 6 activity.

[0078] The diseases associated with histone deacetylase 6 activity include cancer, inflammatory diseases, autoimmune diseases, neurological or neurodegenerative diseases, and specifically include lung cancer, colon cancer, breast cancer, prostate cancer, liver cancer, brain cancer, ovarian cancer, gastric cancer, skin cancer, pancreatic cancer, glioma, glioblastoma, leukemia, lymphoma, multiple myeloma, solid tumors, Wilson's disease, spinal cerebral ataxia, prion disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, amyloidosis, Alzheimer's disease, alcoholic liver disease, spinal muscular atrophy, rheumatoid arthritis, and osteoarthritis, as well as other symptoms or diseases associated with the abnormal function of histone deacetylase.

[0079] According to one embodiment of the present invention, examples of the histone deacetylase-mediated diseases include infectious diseases, neoplasms, endocrine, nutritional and metabolic diseases, mental and behavioral disorders, neurological diseases, eye and appendage diseases, cardiovascular diseases, respiratory diseases, gastrointestinal diseases, skin and subcutaneous tissue diseases, musculoskeletal and connective tissue diseases, or congenital malformations, deformities and chromosomal abnormalities, as well as other conditions or diseases associated with abnormal function of histone deacetylase 6.

[0080] In the present invention, the infectious disease may be a prion disease. The neoplasm 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 carcinoma, breast cancer, melanoma, skin cancer, liver cancer, brain cancer, gastric cancer, ovarian cancer, pancreatic cancer, head and neck cancer, oral cancer, or glioma). The endocrine, nutritional, and metabolic disease may be Wilson's disease, amyloidosis, or diabetes. The mental and behavioral disorder may be depression or Rett syndrome. The neurological disease may be a central nervous system atrophy (e.g., Huntington's disease, spinal muscular atrophy (SMA), spinocerebellar ataxia (SCA)), a neurodegenerative disease (e.g., Alzheimer's disease), a movement disorder (e.g., Parkinson's disease), a neuropathy (e.g., hereditary neuropathy (Charcot-Marie-Tooth disease), sporadic neurodegeneration, inflammatory neuropathy, or drug-induced neurodegeneration), a motor neuron disease (e.g., amyotrophic lateral sclerosis (ALS)), or a central nervous system demyelinating disease (e.g., multiple sclerosis (MS)). The eye and adnexal disease may be uveitis. The cardiovascular disease may be atrial fibrillation or stroke. The respiratory disease may be asthma. The gastrointestinal disease may be alcoholic liver disease, inflammatory bowel disease, Crohn's disease, or ulcerative colitis. The skin and subcutaneous tissue disease may be psoriasis. The musculoskeletal and connective tissue disease may be rheumatoid arthritis, osteoarthritis, or systemic lupus erythematosus (SLE), and the congenital malformation, deformity, or chromosomal abnormality may be autosomal dominant polycystic kidney disease.

[0081] The stereoisomers and pharmaceutically acceptable salts thereof are as described above in the description of the stereoisomers and pharmaceutically acceptable salts of the compounds of formula I of the present invention.

[0082] The pharmaceutical compositions of the present invention may further comprise one or more pharmaceutically acceptable carriers for administration in addition to the compound represented by Formula I, its stereoisomer, or a pharmaceutically acceptable salt thereof. The pharmaceutically acceptable carriers may include saline, sterile water, Ringer's solution, buffered saline, dextrose solution, maltodextrin solution, glycerol, ethanol, or a mixture of one or more of these components. Other common additives, such as antioxidants, buffers, and bacteriostats, may be added as needed. Furthermore, the compositions may be formulated into injectable forms, such as aqueous solutions, suspensions, and emulsions, as well as pills, capsules, granules, or tablets, by adding diluents, dispersants, surfactants, binders, and lubricants. Therefore, the compositions of the present invention may be in the form of patches, liquids, pills, capsules, granules, tablets, suppositories, and the like. These preparations can be prepared by conventional methods used in the art or by the methods disclosed in Remington's Pharmaceutical Sciences (latest edition), Mack Publishing Company, Easton PA, and can be formulated into various preparations depending on the disease or ingredient.

[0083] The composition of the present invention can be administered orally or parenterally (for example, intravenously, subcutaneously, intraperitoneally, or topically) depending on the intended method, and the dosage range varies depending on the patient's weight, age, sex, health condition, diet, administration time, administration method, excretion rate, severity of disease, etc. The daily dosage of the compound represented by formula I of the present invention is approximately 1 to 1000 mg / kg, preferably 5 to 100 mg / kg, and can be administered once or in divided doses per day.

[0084] The pharmaceutical composition of the present invention may further contain one or more active ingredients exhibiting the same or similar pharmacological effects in addition to the compound represented by Formula I, its stereoisomer, or a pharmaceutically acceptable salt thereof.

[0085] According to a specific embodiment, the present invention provides a method for preventing or treating a disease associated with histone deacetylase 6 activity, comprising administering a therapeutically effective amount of a compound represented by Formula I, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof to a subject in need thereof. The subject may be a mammal, including a human.

[0086] The method for preventing or treating a disease associated with histone deacetylase 6 activity of the present invention includes not only treating the disease itself before the onset of symptoms but also inhibiting or avoiding the symptoms by administering the compound represented by Formula I, its stereoisomer, or a pharmaceutically acceptable salt thereof. Furthermore, the method for preventing or treating a disease associated with histone deacetylase 6 activity of the present invention may further include administering a therapeutically effective amount of an additional active agent useful for treating the disease together with the compound represented by Formula I, and the additional active agent may exhibit a synergistic or supplementary effect with the compound of Formula I.

[0087] The term "therapeutically effective amount" as used herein refers to an amount of a compound represented by Formula I that is effective in preventing or treating a disease associated with histone deacetylase 6 activity. Specifically, "therapeutically effective amount" refers to an amount sufficient to treat a disease at a reasonable benefit / risk ratio applicable to any medical treatment. The effective dose level can be determined based on factors well known in the medical field, including the type and severity of the individual, age, sex, type of disease, drug activity, drug sensitivity, administration time, administration route and excretion rate, treatment duration, concurrently used drugs, and other factors. The pharmaceutical compositions of the present invention can be administered as an individual therapeutic agent or in combination with other therapeutic agents, and can be administered sequentially or simultaneously with commercially available therapeutic agents. They can be administered in single or multiple doses. Taking these factors into consideration, it is important to administer an amount that achieves maximum efficacy with the minimum amount without side effects, and this can be easily determined by those skilled in the art. The dosage of the pharmaceutical compositions of the present invention can be determined by experts depending on various factors, such as the patient's condition, age, sex, and comorbidities. The active ingredients of the pharmaceutical compositions of the present invention are highly safe and can be used at or above the determined dosage.

[0088] Furthermore, according to one embodiment of the present invention, the present invention provides a method for selectively inhibiting HDAC6, which comprises administering a compound represented by formula I, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof to a mammal, including a human.

[0089] According to one embodiment of the present invention, the present invention provides the use of a compound represented by formula I, a stereoisomer thereof or a pharmaceutically acceptable salt thereof.

[0090] According to one embodiment of the present invention, the present invention also provides use of the compound represented by Formula I, its stereoisomer, or a pharmaceutically acceptable salt thereof for the manufacture of a medicament for treating a disease associated with the activity of histone deacetylase 6. The compound represented by Formula I for the manufacture of the medicament can be mixed with acceptable adjuvants, diluents, carriers, etc., and can be prepared as a combined preparation together with other active ingredients, thereby enhancing the effect of the active ingredient.

[0091] All statements regarding the uses, compositions, and methods of treatment of the present invention apply equally unless they contradict each other.

[0092] The embodiments of the present invention can be modified in various forms, and the scope of the present invention is not limited to the embodiments described below. Furthermore, the embodiments of the present invention are provided to more completely explain the present invention to those having average knowledge in the art. Furthermore, throughout the specification, the term "comprise" a certain element does not exclude other elements, and means that other elements may also be included, unless otherwise specified to the contrary. [Effects of the Invention]

[0093] The compound represented by formula I of the present invention, its stereoisomer, or a pharmaceutically acceptable salt thereof can selectively inhibit HDAC6, and therefore has a significantly excellent preventive or therapeutic effect on diseases associated with histone deacetylase 6 activity. DETAILED DESCRIPTION OF THE INVENTION

[0094] The present invention will be described in more detail below through examples and experimental examples. However, these examples are merely illustrative of the present invention and are not intended to limit the scope of the present invention. [Example]

[0095] Production of 1,3,4-oxadiazole derivative compounds A specific method for producing the compound represented by formula I is as follows.

[0096] Example 5: Synthesis of compound 5,3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-(2-thienyl)-1,3,4-oxadiazol-2-one [Step 1] Synthesis of 6-methylnicotinohydrazide [ka]

[0097] Hydrazine monohydrate (32.151 mL, 661.507 mmol) was added to a solution of methyl 6-methylnicotinate (10.000 g, 66.151 mmol) in ethanol (200 mL) at room temperature, and the mixture was stirred at the same temperature for 18 hours. The solvent was removed from the reaction mixture under reduced pressure, and the resulting concentrate was poured into water and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate and dried over anhydrous magnesium sulfate, then filtered and concentrated under reduced pressure. The resulting product was used without further purification (8.248 g, 82.5%, white solid).

[0098] [Step 2] Synthesis of 2-(difluoromethyl)-5-(6-methylpyridin-3-yl)-1,3,4-oxadiazole [ka]

[0099] To a solution of 6-methylnicotinohydrazide (8.248 g, 54.561 mmol) synthesized in Step 1 in tetrahydrofuran (200 mL) at 0 °C, triethylamine (38.024 mL, 272.805 mmol) was added 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 the mixture was stirred at 80 °C for an additional 3 hours. The temperature was then lowered to room temperature to terminate the reaction. Saturated aqueous sodium bicarbonate was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, removed with anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 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.

[0100] [Step 3] Synthesis of 2-(6-(bromomethyl)-pyridin-3-yl)-5-(difluoromethyl)-1,3,4-oxadiazole [ka]

[0101] 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, 8.110 g, 45.569 mmol), and azobisisobutyronitrile (AIBN, 0.624 g, 3.797 mmol) in 1,2-dichloroethane (120 mL) was stirred at room temperature for 6 hours. Water was poured into the reaction mixture, which was then extracted with dichloromethane. The organic layer was washed with saturated aqueous ammonium chloride and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 80 g cartridge; ethyl acetate / hexane = 0% to 40%) and concentrated to give the title compound (3.960 g, 36.0%) as a brown solid.

[0102] [Step 4] Synthesis of thiophene-2-carbohydrazide [ka]

[0103] Hydrazine monohydrate (100.00% solution, 1.367 mL, 28.100 mmol) was added to a solution of methylthiophene-2-carboxylate (100.00% solution, 0.163 mL, 1.410 mmol) in ethanol (10 mL) at room temperature, and the mixture was stirred at 60 °C for 5 hours. The temperature was then lowered to room temperature to terminate the reaction. The solvent was removed from the reaction mixture under reduced pressure, and the concentrate was poured into saturated aqueous sodium bicarbonate and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and dried over anhydrous magnesium sulfate, then filtered and concentrated under reduced pressure. The product was used without further purification (0.2 g, 99.8%, pale yellow solid).

[0104] [Step 5] Synthesis of 5-(2-thienyl)-3H-1,3,4-oxadiazol-2-one [ka]

[0105] Thiophene-2-carbohydrazide (100.00%, 0.200 g, 1.407 mmol) synthesized in Step 4 and 1,1'-carbonylbis-1H-imidazole (100.00%, 0.274 g, 1.690 mmol) were dissolved in tetrahydrofuran (10 mL) at room temperature. Triethylamine (100.00% solution, 0.273 mL, 2.000 mmol) was added and stirred at the same temperature overnight. Water was poured into the reaction mixture, which was then extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and then dried over anhydrous magnesium sulfate. It was then filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; methanol / dichloromethane = 0% to 10%) and concentrated to give the title compound (0.143 g, 60.450%, pale yellow solid).

[0106] [Step 6] Synthesis of Compound 5 [ka]

[0107] 2-[6-(bromomethyl)-3-pyridyl]-5-(difluoromethyl)-1,3,4-oxadiazole (100.00%, 0.122 g, 0.421 mmol) prepared in Step 3 was added to a solution of 5-(2-thienyl)-3H-1,3,4-oxadiazol-2-one (100.00%, 0.063 g, 0.350 mmol) prepared in Step 5 and potassium carbonate (100.00%, 0.049 g, 0.494 mmol) in N,N-dimethylformamide (2 mL) at room temperature, and the mixture was stirred overnight at the same temperature. Water was poured into the reaction mixture, which was then extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified and concentrated by column chromatography (SiO2, 4 g cartridge; methanol / dichloromethane = 0% to 10%), and the resulting product was purified again by chromatography (SiO2, 4 g cartridge; methanol / dichloromethane = 0% to 10%) and concentrated to give the title compound (0.036 g, 26.44%, yellow solid).

[0108] 1 H NMR (400 MHz, CDCl3)δ 9.34-9.33(m, 1H), 8.44(dd, J=8.2, 2.2 Hz, 1H), 7.65(dd, J=4.0, 1.2 Hz, 1H), 7.55-7.52(m, 2H), 7.17-7.15(m, 1H), 6.96(t, J=51.6 Hz, 1H), 5.22(s, 2H); LRMS(ES)m / z 378.7(M + +1).

[0109] Following substantially the same method as in Example 5, the compounds in Table 2 below were synthesized.

[0110] [Table 8]

[0111] 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-oxadiazole-2(3H)-thione [Step 1] Synthesis of benzohydrazine [ka]

[0112] A solution of methyl benzoate (0.500 g, 2.203 mmol) and hydrazine monohydrate (0.920 mL, 7.308 mmol) in ethanol (12 mL) was heated to reflux for 18 hours, and then the temperature was lowered to room temperature to terminate the reaction. The solvent was removed from the reaction mixture under reduced pressure, and the resulting product was used without further purification (0.500 g, 100.0%, white solid).

[0113] [Step 2] Synthesis of 5-phenyl-1,3,4-oxadiazole-2(3H)-thione [ka]

[0114] To a solution of the benzohydrazide (100.00%, 0.500 g, 3.672 mmol) synthesized in Step 1 in ethanol (12 mL) at room temperature, potassium ethylxanthate (100.00%, 0.589 g, 3.674 mmol) was added and stirred at the same temperature. The solvent was removed from the reaction mixture under reduced pressure, and the precipitated solid was filtered, washed with water, and dried to obtain the title compound (0.45 g, 68.759%) as a pale yellow solid.

[0115] [Step 3] Synthesis of compound 45 [ka]

[0116] To a solution of 5-phenyl-1,3,4-oxadiazole-2(3H)-thione (100.00%, 50.000 mg, 0.281 mmol) synthesized in Step 1 in N,N-dimethylformamide (2 mL) at room temperature, potassium carbonate (100.00%, 40.000 mg, 0.404 mmol) was added and stirred at the same temperature for 0.3 hours. 2-[6-(bromomethyl)-3-pyridyl]-5-(difluoromethyl)-1,3,4-oxadiazole (100.00%, 100.000 mg, 0.345 mmol) was added to the reaction mixture, which was then stirred at 35°C for an additional 18 hours. Water was poured into the reaction mixture, which was then extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; hexane / ethyl acetate = 100% to 50%) and concentrated to give the title compound (58 mg, 53.36%) in the form of a white solid.

[0117] 1 H NMR (400 MHz, CDCl3)δ 9.32(d, J=1.6 Hz, 1H), 8.40(dd, J=8.2, 2.2 Hz, 1H), 8.01(dd, J=8.2, 1.4 Hz, 2H), 7.83(d, J=8.4 Hz, 1H), 7.56-7.51(m, 3H), 6.96(t, J=51.6 Hz, 1H), 4.75(s, 2H); LRMS(ES)m / z 388.8(M + +1).

[0118] The compounds in Table 3 below were synthesized according to substantially the same method as in Example 45.

[0119] [Table 9] [Table 10]

[0120] Example 43: Synthesis of Compound 43, 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-phenyl-1,3,4-thiadiazol-2-one [Step 1] Synthesis of benzohydrazide [ka]

[0121] A solution of methyl benzoate (100.00%, 1.000 g, 7.345 mmol) and hydrazine monohydrate (100.00%, 3.677 g, 73.452 mmol) in ethanol (80 mL) at 90 °C was stirred overnight at the same temperature, then the temperature was lowered to room temperature to complete the reaction. The solvent was removed from the reaction mixture under reduced pressure, and water was poured into the resulting concentrate, which was then extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate and dried over anhydrous magnesium sulfate, then filtered and concentrated under reduced pressure. The resulting product was used without further purification (0.88 g, 88.000%, white solid).

[0122] [Step 2] Synthesis of benzenecarbothiohydrazide [ka]

[0123] A solution of the benzohydrazide (100.00%, 0.500 g, 3.672 mmol) synthesized in Step 1 and Lawesson's reagent (100.00%, 1.782 g, 4.406 mmol) in toluene (20 mL) was stirred at 100 °C overnight at the same temperature, then the temperature was lowered to room temperature to terminate the reaction. Water was poured into the reaction mixture and extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride and dried over anhydrous magnesium sulfate, then filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 30%) and concentrated to yield the title compound (0.31 g, 55.455%, white solid).

[0124] [Step 3] Synthesis of 5-phenyl-3H-1,3,4-thiadiazol-2-one [ka]

[0125] A solution of benzenecarbothiohydrazide (100.00%, 0.280 g, 1.839 mmol) synthesized in Step 2 and 1,1'-carbonylbis-1H-imidazole (100.00%, 0.358 g, 2.208 mmol) in dichloromethane (20 mL) was stirred at 50 °C overnight at the same temperature, then the temperature was lowered to room temperature to complete the reaction. Water was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and dried over anhydrous magnesium sulfate, then filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 24 g cartridge; ethyl acetate / hexane = 0% to 30%) and concentrated to yield the title compound (0.25 g, 76.264%, white solid).

[0126] [Step 4] Synthesis of compound 43 [ka]

[0127] A solution of 5-phenyl-3H-1,3,4-thiadiazol-2-one (100.00%, 0.050 g, 0.281 mmol) synthesized in Step 3 and potassium carbonate (100.00%, 0.058 g, 0.420 mmol) in N,N-dimethylformamide (5 mL) was stirred at room temperature for 30 minutes, and then 2-[6-(bromomethyl)-3-pyridyl]-5-(difluoromethyl)-1,3,4-oxadiazole (100.00%, 0.085 g, 0.293 mmol) and potassium iodide (100.00%, 0.023 g, 0.139 mmol) were added and stirred at the same temperature overnight. Water was poured into the reaction mixture, which was then extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; ethyl acetate / hexane = 0% to 50%) and concentrated to give the title compound (0.054 g, 49.68%, white solid).

[0128] 1 H NMR (400 MHz, CDCl3) δ 9.33 (d, J=1.6 Hz, 1H), 8.42 (dd, J=8.2, 2.2 Hz, 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).

[0129] Following substantially the same method as in Example 43, the compounds in Table 4 below were synthesized.

[0130] [Table 11]

[0131] Example 4 Synthesis of Compound 4, 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[2-fluoro-4-[(4-methyl-1-piperidyl)methyl]phenyl]-1,3,4-oxadiazol-2-one [Step 1] Synthesis of methyl 2-fluoro-4-[(4-methyl-1-piperidyl)methyl]benzoate [ka]

[0132] A solution of methyl 2-fluoro-4-formylbenzoate (100.00%, 0.300 g, 1.647 mmol), 4-methylpiperidine (100.00%, 2.000 equiv., 3.294 mmol), and sodium triacetoxyborohydride (100.00%, 2.000 equiv., 3.294 mmol) in dichloromethane (10 mL) was stirred at room temperature overnight. Water was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; ethyl acetate / hexane = 0% to 100%) and concentrated to give the title compound (0.43 g, 98.41%, yellow oil).

[0133] [Step 2] Synthesis of 2-fluoro-4-[(4-methyl-1-piperidyl)methyl]benzohydrazide [ka]

[0134] A solution of methyl 2-fluoro-4-[(4-methyl-1-piperidyl)methyl]benzoate (100.00%, 0.420 g, 1.583 mmol) synthesized in Step 1 and hydrazine monohydrate (100.00%, 10.000 equivalents, 15.830 mmol) in ethanol (10 mL) at 80 ° C was stirred overnight at the same temperature, and then the temperature was lowered to room temperature to complete the reaction. The solvent was removed from the reaction mixture under reduced pressure, and the resulting product was used without further purification (0.42 g, 100.0%, white solid).

[0135] [Step 3] Synthesis of 5-[2-fluoro-4-[(4-methyl-1-piperidyl)methyl]phenyl]-3H-1,3,4-oxadiazol-2-one [ka]

[0136] A solution of 2-fluoro-4-[(4-methyl-1-piperidyl)methyl]benzohydrazide (100.00%, 0.420 g, 1.583 mmol), triphosgene (100.00%, 0.400 equivalents, 0.633 mmol), and N,N-diisopropylethylamine (100.00%, 2.000 equivalents, 3.166 mmol) in dichloromethane (10 mL) was stirred at 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 and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 100%) and concentrated to give the title compound (0.275 g, 59.63%, white solid).

[0137] [Step 4] Synthesis of Compound 4 [ka]

[0138] A solution of 5-[2-fluoro-4-[(4-methyl-1-piperidyl)methyl]phenyl]-3H-1,3,4-oxadiazol-2-one (100.00%, 0.090 g, 0.309 mmol), 2-[6-(bromomethyl)-3-pyridyl]-5-(difluoromethyl)-1,3,4-oxadiazole (100.00%, 1.200 equivalents, 0.371 mmol), potassium carbonate (100.00%, 2.000 equivalents, 0.618 mmol), and potassium iodide (100.00%, 1.100 equivalents, 0.340 mmol) in N,N-dimethylformamide (5 mL) was stirred overnight at the same temperature. Water was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and then filtered with anhydrous magnesium sulfate, then concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; ethyl acetate / hexane = 0% to 100%) and concentrated to give the title compound (0.07 g, 45.27%, white solid).

[0139] 1 H NMR (400 MHz, CDCl3)δ 9.25(s, 1H), 8.37(d, J=10.0 Hz, 1H), 7.69(t, J=7.6 Hz, 1H), 7.49(d, J=8.0 Hz, 1H), 7.21-7.18(m, 2H), 6.93(t, J=51.6 Hz, 1H), 5.22(s, 2H), 3.47(s, 2H), 2.76(d, J=11.2 Hz, 2H), 1.95(t, J=10.8 Hz, 2H), 1.57(d, J=12.0 Hz, 2H), 1.34-1.20(m, 3H), 0.89(d, J=6.0 Hz, 3H);LRMS(ES)m / z 501.4(M + +1).

[0140] Following substantially the same method as in Example 4, the compounds in Table 5 below were synthesized.

[0141] [Table 12]

[0142] 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-oxadiazole-2(3H)-thione [Step 1] Synthesis of methyl 3-(1,3-dioxolan-2-yl)benzoate [ka]

[0143] A mixture of methyl 3-formylbenzoate (100.00%, 2.000 g, 12.183 mmol), ethylene glycol (100.00%, 3.781 g, 60.920 mmol), and 4-methylbenzenesulfonic acid hydrate (100.00%, 0.232 g, 1.220 mmol) in toluene (120 mL) was heated to reflux overnight. The mixture was cooled to room temperature, poured into water, and extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride, removed with anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 80 g cartridge; ethyl acetate / hexane = 0% to 10%) and concentrated to give the title compound (1.8 g, 70.959%, ​​white solid).

[0144] [Step 2] Synthesis of 3-(1,3-dioxolan-2-yl)benzohydrazide [ka]

[0145] A solution of methyl 3-(1,3-dioxolan-2-yl)benzoate (100.00%, 1.130 g, 5.427 mmol) synthesized in Step 1 and hydrazine monohydrate (100.00%, 2.717 g, 54.275 mmol) in ethanol (80 mL) was stirred at 80 °C overnight at the same temperature, then the temperature was lowered to room temperature to complete the reaction. Water was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate and dried over anhydrous magnesium sulfate, then filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 24 g cartridge; methanol / dichloromethane = 0% to 5%) and concentrated to yield the title compound (1.1 g, 97.345%, white solid).

[0146] [Step 3] Synthesis of 5-[3-(1,3-dioxolan-2-yl)phenyl]-3H-1,3,4-oxadiazole-2-thione [ka]

[0147] A solution of 3-(1,3-dioxolan-2-yl)benzohydrazide (100.00%, 0.900 g, 4.323 mmol) synthesized in Step 2 and potassium ethylxanthate (100.00%, 0.762 g, 4.754 mmol) in ethanol (50 mL) was stirred at 80 °C overnight at the same temperature, then the temperature was lowered to room temperature to complete the reaction. Water was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and dried over anhydrous magnesium sulfate, then filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 24 g cartridge; ethyl acetate / hexane = 0% to 30%) and concentrated to give the title compound (0.7 g, 64.70%, white solid).

[0148] [Step 4] Synthesis of 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[3-(1,3-dioxolan-2-yl)phenyl]-1,3,4-oxadiazole-2-thione [ka]

[0149] A solution of 5-[3-(1,3-dioxolan-2-yl)phenyl]-3H-1,3,4-oxadiazole-2-thione (100.00%, 0.350 g, 1.398 mmol), 2-[6-(bromomethyl)-3-pyridyl]-5-(difluoromethyl)-1,3,4-oxadiazole (100.00%, 0.426 g, 1.469 mmol), potassium carbonate (100.00%, 0.208 g, 2.099 mmol), and potassium iodide (100.00%, 0.116 g, 0.699 mmol) in N,N-dimethylformamide (30 mL) was stirred at room temperature for 30 minutes and then overnight at the same temperature. Water was poured into the reaction mixture and extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 50%) and concentrated to give the title compound (0.51 g, 79.39%, white solid).

[0150] [Step 5] Synthesis of 3-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-thioxo-1,3,4-oxadiazol-2-yl]benzaldehyde [ka]

[0151] A solution of 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[3-(1,3-dioxolan-2-yl)phenyl]-1,3,4-oxadiazole-2-thione (100.00%, 0.500 g, 1.088 mmol) synthesized in Step 4 and ferric chloride hexahydrate (100.00%, 1.030 g, 3.811 mmol) in dichloromethane (30 mL) was stirred at room temperature overnight. Water was poured into the reaction mixture, which was then extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and dried over anhydrous magnesium sulfate, then filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 40%) and concentrated to give the title compound (0.350 g, 77.41%) as a white solid.

[0152] [Step 6] Synthesis of compound 84 [ka]

[0153] N-methylmethanamine (100.00%, 0.007 g, 0.155 mmol) was added to a solution of 4-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-thioxo-1,3,4-oxadiazol-2-yl]benzaldehyde (100.00%, 0.030 g, 0.072 mmol) synthesized in Step 5 in dichloromethane (5 mL) at room temperature, and the mixture was stirred at the same temperature for 30 minutes. Water was poured into the reaction mixture, which was then extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate and dried over anhydrous magnesium sulfate, then filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; methanol / dichloromethane = 0% to 5%) and concentrated to give the title compound (0.011 g, 34.27%, white solid).

[0154] 1H NMR(400 MHz, CDCl3)δ 9.32(d, J=1.7 Hz, 1H), 8.39(dd, J=8.2, 2.2 Hz, 1H), 7.94-7.90(m, 2H), 7.83(d, J=8.2 Hz, 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).

[0155] Following substantially the same method as in Example 84, the compounds in Table 6 below were synthesized.

[0156] [Table 13] [Table 14] [Table 15] [Table 16] [Table 17] [Table 18] [Table 19] [Table 20]

[0157] Example 132: Synthesis of Compound 132, 5-[4-(azetidin-1-ylmethyl)phenyl]-3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-1,3,4-oxadiazol-2-one [Step 1] Synthesis of methyl 4-(1,3-dioxolan-2-yl)benzoate [ka]

[0158] A mixture of methyl 4-formylbenzoate (100.00%, 3.000 g, 18.275 mmol), ethylene glycol (100.00%, 5.672 g, 91.380 mmol), and 4-methylbenzenesulfonic acid hydrate (100.00%, 0.348 g, 1.830 mmol) in toluene (150 mL) was heated to reflux overnight. The mixture was cooled to room temperature, poured into water, and extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 80 g cartridge; ethyl acetate / hexane = 0% to 10%) and concentrated to give the title compound (3.5 g, 91.984%, white solid).

[0159] [Step 2] Synthesis of 4-(1,3-dioxolan-2-yl)benzohydrazide [ka]

[0160] A mixture of methyl 4-(1,3-dioxolan-2-yl)benzoate (100.00%, 2.000 g, 9.606 mmol) synthesized in Step 1 and hydrazine monohydrate (100.00%, 4.809 g, 96.065 mmol) in ethanol (100 mL) was heated to reflux overnight. After cooling to room temperature, water was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 40 g cartridge; methanol / dichloromethane = 0% to 5%) and concentrated to give the title compound (1.8 g, 90.000%, white solid).

[0161] [Step 3] Synthesis of 5-[4-(1,3-dioxolan-2-yl)phenyl]-3H-1,3,4-oxadiazol-2-one [ka]

[0162] A mixture of 4-(1,3-dioxolan-2-yl)benzohydrazide (100.00%, 0.650 g, 3.122 mmol) synthesized in Step 2 and 1,1'-carbonylbis-1H-imidazole (100.00%, 0.607 g, 3.744 mmol) in dichloromethane (50 mL) was heated to reflux overnight. After cooling to room temperature, the reaction mixture was poured into water and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 50%) and concentrated to give the title compound (0.45 g, 61.545%, white solid).

[0163] [Step 4] Synthesis of 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[4-(1,3-dioxolan-2-yl)phenyl]-1,3,4-oxadiazol-2-one [ka]

[0164] To a solution of 5-[4-(1,3-dioxolan-2-yl)phenyl]-3H-1,3,4-oxadiazol-2-one (100.00%, 0.500 g, 2.135 mmol) and potassium carbonate (100.00%, 0.443 g, 3.205 mmol) in N,N-dimethylformamide (30 mL) at room temperature, 2-[6-(bromomethyl)-3-pyridyl]-5-(difluoromethyl)-1,3,4-oxadiazole (100.00%, 0.650 g, 2.241 mmol) and potassium iodide (100.00%, 0.177 g, 1.066 mmol) were added and stirred at the same temperature for 30 minutes. The reaction mixture was poured into water and extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride, removed with anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. Ethyl acetate (5 mL) was added to the concentrate and stirred. The precipitated solid was filtered, washed with hexane, and dried to obtain the title compound (0.74 g, 78.18%, white solid).

[0165] [Step 5] Synthesis of 4-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-oxo-1,3,4-oxadiazol-2-yl]benzaldehyde [ka]

[0166] A solution of 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[4-(1,3-dioxolan-2-yl)phenyl]-1,3,4-oxadiazol-2-one (100.00%, 0.280 g, 0.632 mmol) synthesized in Step 4 and ferric chloride hexahydrate (100.00%, 0.512 g, 1.894 mmol) in dichloromethane (30 mL) was stirred at the same temperature overnight. Water was poured into the reaction mixture, which was then extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and dried over anhydrous magnesium sulfate, then filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 50%) and concentrated to give the title compound (0.18 g, 71.39%, white solid).

[0167] [Step 6] Synthesis of Compound 132 [ka]

[0168] A solution of 4-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-oxo-1,3,4-oxadiazol-2-yl]benzaldehyde (100.00%, 0.030 g, 0.075 mmol) synthesized in Step 5 and azetidine hydrochloride (100.00%, 0.014 g, 0.150 mmol) in dichloromethane (5 mL) was stirred at room temperature for 30 minutes, and sodium triacetoxyborohydride (100.00%, 0.048 g, 0.227 mmol) was added and stirred at the same temperature overnight. Water was poured into the reaction mixture, which was then extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate and dried over anhydrous magnesium sulfate, then filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; methanol / dichloromethane = 0% to 5%) and concentrated to give the title compound (0.019 g, 57.42%, white solid).

[0169] 1 H NMR (400 MHz, CDCl3)δ 9.33(d, J=1.5 Hz, 1H), 8.43(dd, J=8.2, 2.2 Hz, 1H), 7.82(d, J=8.3 Hz, 2H), 7.55-7.52(m, 1 H), 7.43(d, J=8.1 Hz, 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).

[0170] The compounds in Table 7 below were synthesized in substantially the same manner as in Example 132.

[0171] [Table 21]

[0172] Example 83: Synthesis of Compound 83, 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[4-[(4-isopropylpiperazin-1-yl)methyl]phenyl]-1,3,4-oxadiazol-2-one [Step 1] Synthesis of tert-butyl 4-[(4-methoxycarbonylphenyl)methyl]piperazine-1-carboxylate [ka]

[0173] A solution of methyl 4-formylbenzoate (100.00%, 0.500 g, 3.046 mmol), tert-butyl piperazine-1-carboxylate (100.00%, 0.681 g, 3.656 mmol), and sodium triacetoxyborohydride (100.00%, 1.291 g, 6.091 mmol) in dichloromethane (20 mL) was stirred at room temperature overnight. Water was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate and dried over anhydrous magnesium sulfate, then filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 24 g cartridge; ethyl acetate / hexane = 0% to 30%) and concentrated to give the title compound (0.89 g, 87.38%, white solid).

[0174] [Step 2] Synthesis of tert-butyl 4-[[4-(hydrazinecarbonyl)phenyl]methyl]piperazine-1-carboxylate [ka]

[0175] A solution of tert-butyl 4-[(4-methoxycarbonylphenyl)methyl]piperazine-1-carboxylate (100.00%, 0.300 g, 0.897 mmol) synthesized in Step 1 and hydrazine monohydrate (100.00%, 0.449 g, 8.969 mmol) in ethanol (20 mL) was stirred at 90 °C overnight at the same temperature, then the temperature was lowered to room temperature to complete the reaction. Water was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate and dried over anhydrous magnesium sulfate, then filtered and concentrated under reduced pressure. The resulting product was used without further purification (0.29 g, 96.67%, white solid).

[0176] [Step 3] Synthesis of tert-butyl 4-[[4-(2-oxo-3H-1,3,4-oxadiazol-5-yl)phenyl]methyl]piperazine-1-carboxylate [ka]

[0177] To a solution of tert-butyl 4-[[4-(hydrazinecarbonyl)phenyl]methyl]piperazine-1-carboxylate (100.00%, 0.500 g, 1.495 mmol) synthesized in Step 2 and 1,1'-carbonylbis-1H-imidazole (100.00%, 0.291 g, 1.795 mmol) in tetrahydrofuran (10 mL) at room temperature, triethylamine (100.00% solution, 0.29 mL, 2.100 mmol) was added and stirred at the same temperature overnight. Water was poured into the reaction mixture, which was then extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and dried over anhydrous magnesium sulfate, then filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 24 g cartridge; methanol / dichloromethane = 0% to 10%) and concentrated to give the title compound (0.468 g, 86.85%, white solid).

[0178] [Step 4] Synthesis of tert-butyl 4-[[4-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-oxo-1,3,4-oxadiazol-2-yl]phenyl]methyl]piperazine-1-carboxylate [ka]

[0179] 2-[6-(bromomethyl)-3-pyridyl]-5-(difluoromethyl)-1,3,4-oxadiazole (100.00%, 0.228 g, 0.786 mmol) prepared in Step 3 of Example 5 was added to a solution of tert-butyl 4-[[4-(2-oxo-3H-1,3,4-oxadiazol-5-yl)phenyl]methyl]piperazine-1-carboxylate (100.00%, 0.236 g, 0.655 mmol) prepared in Step 3 of Example 5 and potassium carbonate (100.00%, 0.091 g, 0.918 mmol) in N,N-dimethylformamide (3 mL) at room temperature. The mixture was stirred overnight at the same temperature. Water was poured into the reaction mixture, which was then extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride and dehydrated with anhydrous magnesium sulfate. The mixture was then filtered and concentrated under reduced pressure. The concentrate was purified and concentrated by column chromatography (SiO2, 4 g cartridge; ethyl acetate / hexane = 0% to 60%), and the resulting product was purified again by chromatography (SiO2, 4 g cartridge; methanol / dichloromethane = 0% to 10%) and concentrated to give the title compound (0.37 g, 99.20%, white solid).

[0180] [Step 5] Synthesis of 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[4-(piperazin-1-ylmethyl)phenyl]-1,3,4-oxadiazol-2-one [ka]

[0181] A solution of tert-butyl 4-[[4-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-oxo-1,3,4-oxadiazol-2-yl]phenyl]methyl]piperazine-1-carboxylate (100.00%, 0.370 g, 0.650 mmol) synthesized in Step 4 and trifluoroacetic acid (100.00% solution, 0.497 mL, 6.490 mmol) in dichloromethane (3 mL) was stirred at room temperature overnight. Saturated aqueous sodium bicarbonate solution was poured into the reaction mixture and 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 (0.3 g, 98.39%, yellow oil).

[0182] [Step 6] Synthesis of Compound 83 [ka]

[0183] 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[4-(piperazin-1-ylmethyl)phenyl]-1,3,4-oxadiazol-2-one (100.00%, 0.075 g, 0.160 mmol) synthesized in Step 5, acetone (100.00% solution, 0.019 mL, 0.257 mmol) and N-ethyl-N-isopropyl-propan-2-amine (100.00% solution, 0.056 mL, 0.322 mmol) in dichloromethane (1 mL) was stirred at room temperature for 30 minutes, sodium triacetoxyborohydride (100.00%, 0.101 g, 0.479 mmol) was added, and the mixture was stirred at the same temperature for an additional 18 hours. Saturated aqueous sodium bicarbonate was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; dichloromethane / methanol = 0% to 10%) and concentrated to give the title compound (0.014 g, 17.13%, pale yellow solid).

[0184] 1 H NMR (400 MHz, CD3OD)δ 9.25(d, J=1.6 Hz, 1H), 8.53(dd, J=8.2, 2.2 Hz, 1H), 7.85(d, J=8.4 Hz, 2H), 7.72(d, J=8.0 Hz, 1H), 7.53(d, J=8.4 Hz, 2H), 7.26(t, J=51.6 Hz, 1H), 5.26(s, 2H), 3.63(s, 2H), 2.74-2.59(m, 9H), 1.15(d, J=6.8 Hz, 6H);LRMS(ES)m / z 512.8(M + +1).

[0185] Example 66: Synthesis of Compound 66, 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[4-(4-isopropylpiperazin-1-yl)phenyl]-1,3,4-thiadiazol-2-one [Step 1] Synthesis of tert-butyl 4-[[4-(aminocarbamothioyl)phenyl]methyl]piperazine-1-carboxylate [ka]

[0186] A solution of tert-butyl 4-[[4-(hydrazinecarbonyl)phenyl]methyl]piperazine-1-carboxylate (100.00%, 1.000 g, 2.990 mmol) synthesized in Step 2 of Example 86 and Lawesson's reagent (100.00%, 1.451 g, 3.587 mmol) in toluene (40 mL) was stirred at 80 °C overnight at the same temperature, then the temperature was lowered to room temperature to complete the reaction. 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 and dehydrated with anhydrous magnesium sulfate, then filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 24 g cartridge; ethyl acetate / hexane = 0% to 60%) and concentrated to give the title compound (0.61 g, 58.20%, white solid).

[0187] [Step 2] Synthesis of tert-butyl 4-[[4-(2-oxo-3H-1,3,4-thiadiazol-5-yl)phenyl]methyl]piperazine-1-carboxylate [ka]

[0188] A solution of tert-butyl 4-[[4-(aminocarbamothioyl)phenyl]methyl]piperazine-1-carboxylate (100.00%, 0.500 g, 1.427 mmol) synthesized in Step 1 and 1,1'-carbonylbis-1H-imidazole (100.00%, 0.278 g, 1.715 mmol) in dichloromethane (30 mL) was stirred at 50 °C overnight at the same temperature and then cooled to room temperature to complete the reaction. Water was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous ammonium chloride and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 40%) and concentrated to give the title compound (0.25 g, 46.55%, white solid).

[0189] [Step 3] Synthesis of tert-butyl 4-[[4-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-oxo-1,3,4-thiadiazol-2-yl]phenyl]methyl]piperazine-1-carboxylate [ka]

[0190] A solution of tert-butyl 4-[[4-(2-oxo-3H-1,3,4-thiadiazol-5-yl)phenyl]methyl]piperazine-1-carboxylate (100.00%, 0.100 g, 0.266 mmol) synthesized in Step 2 and potassium carbonate (100.00%, 0.055 g, 0.398 mmol) in N,N-dimethylformamide (10 mL) was stirred at room temperature for 30 minutes, and 2-[6-(bromomethyl)-3-pyridyl]-5-(difluoromethyl)-1,3,4-oxadiazole (100.00%, 0.081 g, 0.279 mmol) and potassium iodide (100.00%, 0.022 g, 0.133 mmol) was added, followed by stirring at the same temperature overnight. Water was poured into the reaction mixture, which was then extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 40%) and concentrated to give the title compound (0.095 g, 61.08%, white solid).

[0191] [Step 4] Synthesis of 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[4-(piperazin-1-ylmethyl)phenyl]-1,3,4-thiadiazol-2-one 2,2,2-trifluoroacetic acid [ka]

[0192] A solution of tert-butyl 4-[[4-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-oxo-1,3,4-thiadiazol-2-yl]phenyl]methyl]piperazine-1-carboxylate (100.00%, 0.090 g, 0.154 mmol) synthesized in Step 3 and trifluoroacetic acid (100.00%, 0.053 g, 0.465 mmol) in dichloromethane (10 mL) was stirred overnight at the same temperature. The reaction mixture was then evaporated under reduced pressure, and the resulting product was used without further purification (0.088 g, 95.51%, yellow oil).

[0193] [Step 5] Synthesis of compound 66 [ka]

[0194] 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[4-(piperazin-1-ylmethyl)phenyl]-1,3,4-thiadiazol-2-one synthesized in Step 4. A solution of 2,2,2-trifluoroacetic acid (100.00%, 0.030 g, 0.051 mmol), acetone (100.00%, 0.006 g, 0.103 mmol), N-ethyldiisopropylamine (100.00% solution, 0.018 mL, 0.103 mmol) and sodium triacetoxyborohydride (100.00%, 0.033 g, 0.156 mmol) in dichloromethane (5 mL) was stirred at room temperature for 30 minutes and then further 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 and then dried over anhydrous magnesium sulfate. The organic layer was then filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; methanol / dichloromethane = 0% to 5%) and concentrated to give the title compound (0.011 g, 41.80%, white solid).

[0195] 1H NMR (400 MHz, CDCl3)δ 9.33(d, J=1.6 Hz, 1H), 8.41(dd, J=8.2, 2.2 Hz, 1H), 7.64(d, J=8.2 Hz, 2H), 7.47(d, J=8.2 Hz, 1H), 7.41(d, J=8.2 Hz, 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=6.5 Hz, 6H);LRMS(ES)m / z 529.35(M + +1).

[0196] Following substantially the same steps as those in Example 66, the compounds in Table 8 below were synthesized.

[0197] [Table 22]

[0198] Example 77: Synthesis of Compound 77, 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[4-[(4-isopropylpiperazin-1-yl)methyl]phenyl]-1,3,4-oxadiazole-2-thione [Step 1] Synthesis of tert-butyl 4-(4-(5-thioxo-4,5-dihydro-1,3,4-oxadiazol-2-yl)benzyl)piperazine-1-carboxylate [ka]

[0199] A mixture of tert-butyl 4-[[4-(hydrazinecarbonyl)phenyl]methyl]piperazine-1-carboxylate (100.00%, 1.000 g, 2.990 mmol) prepared in Step 2 of Example 86 and potassium ethyl xanthate (100.00%, 0.575 g, 3.587 mmol) in ethanol (80 mL) was heated to reflux overnight. After cooling to room temperature, water was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 24 g cartridge; ethyl acetate / hexane = 0% to 40%) and concentrated to give the title compound (0.85 g, 75.50%, white solid).

[0200] [Step 2] Synthesis of tert-butyl 4-[[4-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-thioxo-1,3,4-oxadiazol-2-yl]phenyl]methyl]piperazine-1-carboxylate [ka]

[0201] A solution of tert-butyl 4-[[4-(2-thioxo-3H-1,3,4-oxadiazol-5-yl)phenyl]methyl]piperazine-1-carboxylate (100.00%, 0.500 g, 1.328 mmol) and potassium carbonate (100.00%, 0.197 g, 1.988 mmol) in N,N-dimethylformamide (30 mL) was stirred at room temperature for 30 minutes, and then 2-[6-(bromomethyl)-3-pyridyl]-5-(difluoromethyl)-1,3,4-oxadiazole (100.00%, 0.404 g, 1.393 mmol) and potassium iodide (100.00%, 0.110 g, 0.663 mmol) were added and stirred overnight at the same temperature. The reaction mixture was poured into water and extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 24 g cartridge; ethyl acetate / hexane = 0% to 40%) and concentrated to give the title compound (0.65 g, 83.58%, white solid).

[0202] [Step 3] Synthesis of 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[4-(piperazin-1-ylmethyl)phenyl]-1,3,4-oxadiazole-2-thione 2,2,2-trifluoroacetic acid [ka]

[0203] A solution of tert-butyl 4-[[4-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-thioxo-1,3,4-oxadiazol-2-yl]phenyl]methyl]piperazine-1-carboxylate (100.00%, 0.300 g, 0.512 mmol) synthesized in Step 2 and trifluoroacetic acid (100.00%, 0.175 g, 1.535 mmol) in dichloromethane (20 mL) was stirred at the same temperature for 3 hours. The solvent was removed from the reaction mixture under reduced pressure, and the resulting product was used without further purification (0.28 g, 91.17%, yellow oil).

[0204] [Step 4] Synthesis of compound 77 [ka]

[0205] 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[4-(piperazin-1-ylmethyl)phenyl]-1,3,4-oxadiazole-2-thione synthesized in Step 3. A solution of 2,2,2-trifluoroacetic acid (100.00%, 0.050 g, 0.083 mmol), acetone (100.00%, 0.010 g, 0.172 mmol), and N-ethyldiisopropylamine (100.00% solution, 0.029 mL, 0.167 mmol) in dichloromethane (5 mL) was stirred at room temperature for 30 minutes, and sodium triacetoxyborohydride (100.00%, 0.053 g, 0.250 mmol) was added, followed by additional stirring 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 and then dried over anhydrous magnesium sulfate. The organic layer was then filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; methanol / dichloromethane = 0% to 5%) and concentrated to give the title compound (0.022 g, 50.00%, white solid).

[0206] 1H NMR (400 MHz, CDCl3)δ 9.31(d, J=2.2 Hz, 1H), 8.39(dd, J=8.2, 2.2 Hz, 1H), 7.95(d, J=8.3 Hz, 2H), 7.82(d, J=8.2 Hz, 1H), 7.46(d, J=8.3 Hz, 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=6.5 Hz, 6H);LRMS(ES)m / z 528.87(M + +1).

[0207] The compounds in Table 9 below were synthesized according to substantially the same method as in Example 77.

[0208] [Table 23]

[0209] Example 26: Synthesis of Compound 26, 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[2-fluoro-3-[1-(oxetan-3-yl)-4-piperidyl]phenyl]-1,3,4-oxadiazol-2-one [Step 1] Synthesis of tert-butyl 4-(2-fluoro-3-methoxycarbonyl-phenyl)-3,6-dihydro-2H-pyridine-1-carboxylate [ka]

[0210] A solution of methyl 3-bromo-2-fluorobenzoate (100.00%, 1.000 g, 4.291 mmol), tert-butyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3,6-dihydro-2H-pyridine-1-carboxylate (100.00%, 1.460 g, 4.722 mmol), bis(triphenylphosphine)palladium(II) dichloride (100.00%, 0.301 g, 0.429 mmol), and sodium carbonate (100.00%, 1.365 g, 12.879 mmol) in N,N-dimethylformamide (20 mL) / water (5 mL) was stirred overnight at the same temperature. The reaction mixture was poured into water and extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 24 g cartridge; ethyl acetate / hexane = 0% to 30%) and concentrated to give the title compound (1.100 g, 76.43%, white solid).

[0211] [Step 2] Synthesis of tert-butyl 4-(2-fluoro-3-methoxycarbonyl-phenyl)piperidine-1-carboxylate [ka]

[0212] A solution of tert-butyl 4-(2-fluoro-3-methoxycarbonyl-phenyl)-3,6-dihydro-2H-pyridine-1-carboxylate (100.00%, 0.900 g, 2.683 mmol) synthesized in Step 1 and Pd / C (100.00%, 0.286 g, 2.688 mmol) in methanol (20 mL) was stirred at room temperature overnight. The reaction mixture was filtered through a Celite pad, and the filtrate was stripped of solids and the solvent removed under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 40%) and concentrated to give the title compound (0.74 g, 81.73%, yellow oil).

[0213] [Step 3] Synthesis of tert-butyl 4-[2-fluoro-3-(hydrazinecarbonyl)phenyl]piperidine-1-carboxylate [ka]

[0214] A solution of tert-butyl 4-(2-fluoro-3-methoxycarbonyl-phenyl)piperidine-1-carboxylate (100.00%, 0.700 g, 2.075 mmol) synthesized in Step 2 and hydrazine monohydrate (100.00%, 1.039 g, 20.755 mmol) in ethanol (30 mL) was stirred at room temperature overnight. Water was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The resulting product was used without further purification (0.65 g, 92.86%, white solid).

[0215] [Step 4] Synthesis of tert-butyl 4-[2-fluoro-3-(2-oxo-3H-1,3,4-oxadiazol-5-yl)phenyl]piperidine-1-carboxylate [ka]

[0216] A solution of tert-butyl 4-[2-fluoro-3-(hydrazinecarbonyl)phenyl]piperidine-1-carboxylate (100.00%, 0.700 g, 2.075 mmol) synthesized in Step 3 and 1,1'-carbonylbis-1H-imidazole (100.00%, 0.404 g, 2.492 mmol) in dichloromethane (30 mL) was stirred at room temperature overnight. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous ammonium chloride and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 40%) and concentrated to give the title compound (0.55 g, 72.95%, white solid).

[0217] [Step 5] Synthesis of tert-butyl 4-[3-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-oxo-1,3,4-oxadiazol-2-yl]-2-fluoro-phenyl]piperidine-1-carboxylate [ka]

[0218] To a solution of tert-butyl 4-[2-fluoro-3-(2-oxo-3H-1,3,4-oxadiazol-5-yl)phenyl]piperidine-1-carboxylate (100.00%, 0.400 g, 1.101 mmol) and potassium carbonate (100.00%, 0.164 g, 1.655 mmol) in N,N-dimethylformamide (20 mL) at room temperature, 2-[6-(bromomethyl)-3-pyridyl]-5-(difluoromethyl)-1,3,4-oxadiazole (100.00%, 0.335 g, 1.155 mmol) and potassium iodide (100.00%, 0.091 g, 0.548 mmol) were added and stirred at the same temperature. Water was poured into the reaction mixture, which was then extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 40%) and concentrated to give the title compound (0.54 g, 85.69%, white solid).

[0219] [Step 6] Synthesis of 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[2-fluoro-3-(4-piperidyl)phenyl]-1,3,4-oxadiazol-2-one 2,2,2-trifluoroacetic acid [ka]

[0220] A solution of tert-butyl 4-[3-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-oxo-1,3,4-oxadiazol-2-yl]-2-fluoro-phenyl]piperidine-1-carboxylate (100.00%, 0.300 g, 0.524 mmol) synthesized in Step 5 and 2,2,2-trifluoroacetic acid (100.00%, 0.179 g, 1.570 mmol) in dichloromethane (20 mL) was stirred at the same temperature for 3 hours. After removing the solvent from the reaction mixture under reduced pressure, the resulting product was used without further purification (0.3 g, 97.63%, yellow oil).

[0221] [Step 7] Synthesis of compound 26 [ka]

[0222] A solution of 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[2-fluoro-3-(4-piperidyl)phenyl]-1,3,4-oxadiazol-2-one (2,2,2-trifluoroacetic acid, 100.00%, 0.050 g, 0.085 mmol), N-ethyldiisopropylamine (100.00% solution, 0.03 mL, 0.172 mmol), oxetan-3-one (100.00%, 0.012 g, 0.167 mmol), and sodium triacetoxyborohydride (100.00%, 0.054 g, 0.255 mmol) in dichloromethane (5 mL) 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 and then filtered with anhydrous magnesium sulfate, then concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; methanol / dichloromethane = 0% to 5%) and concentrated to give the title compound (0.031 g, 68.79%, white solid).

[0223] 1H NMR (400 MHz, CDCl3)δ 9.32(d, J=1.6 Hz, 1H), 8.43(dd, J=8.2, 2.2 Hz, 1H), 7.70-7.66(m, 1H), 7.53(dJ=8.2 Hz, 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).

[0224] Following substantially the same method as in Example 26, the compounds in Table 10 below were synthesized.

[0225] [Table 24] [Table 25]

[0226] Example 27: Synthesis of Compound 27, 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[2-fluoro-3-[1-(1-methylazetidin-3-yl)-4-piperidyl]phenyl]-1,3,4-oxadiazol-2-one [Step 1] Synthesis of tert-butyl 3-[4-[3-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-oxo-1,3,4-oxadiazol-2-yl]-2-fluoro-phenyl]-1-piperidyl]azetidine-1-carboxylate [ka]

[0227] 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[2-fluoro-3-(4-piperidyl)phenyl]-1,3,4-oxadiazol-2-one synthesized in step 6 of Example 26 2,2,2-trifluoroacetic acid (100.00%, 0.150 g, 0.256 mmol), N-ethyldiisopropylamine (100.00% solution, 0.089 mL, 0.511 mmol), tert-butyl 3-oxoazetidine-1-carboxylate (100.00%, 0.088 g, 0.514 mmol) and sodium triacetoxyborohydride (100.00%, 0.163 g, 0.769 mmol) in dichloromethane (5 mL) at room temperature was stirred overnight at the same temperature. Water was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; methanol / dichloromethane = 0% to 5%) and concentrated to give the title compound (0.11 g, 68.52%, white solid).

[0228] [Step 2] Synthesis of 5-[3-[1-(azetidin-3-yl)-4-piperidyl]-2-fluoro-phenyl]-3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-1,3,4-oxadiazol-2-one 2,2,2-trifluoroacetic acid [ka]

[0229] A solution of tert-butyl 3-[4-[3-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-oxo-1,3,4-oxadiazol-2-yl]-2-fluoro-phenyl]-1-piperidyl]azetidine-1-carboxylate (100.00%, 0.110 g, 0.175 mmol) synthesized in Step 1 and 2,2,2-trifluoroacetic acid (100.00%, 0.060 g, 0.526 mmol) in dichloromethane (5 mL) was stirred overnight at the same temperature. After removing the solvent from the reaction mixture under reduced pressure, the resulting product was used without further purification (0.100 g, 88.94%, yellow oil).

[0230] [Step 3] Synthesis of compound 27 [ka]

[0231] 5- [3- [1- (azetidin-3-yl) -4-piperidyl] -2-fluoro - phenyl] -3- [ [5- [5- (difluoromethyl) -1,3,4-oxadiazol-2-yl] -2-pyridyl] methyl] -1,3,4-oxadiazol-2-one synthesized in step 2 2,2,2-trifluoroacetic acid (100.00%, 0.050 g, 0.078 mmol), formaldehyde (100.00%, 0.005 g, 0.167 mmol), N- ethyldi-isopropylamine (100.00% solution, 0.027 mL, 0.155 mmol) and sodium triacetoxyborohydride (100.00%, 0.050 g, 0.236 mmol) in dichloromethane (5 mL) at room temperature was stirred overnight at the same temperature. Water was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; methanol / dichloromethane = 0% to 5%) and concentrated to give the title compound (0.029 g, 68.71%, white solid).

[0232] 1 H NMR (400 MHz, CDCl3)δ 9.31(d, J=1.6 Hz, 1H), 8.43(dd, J=8.2, 2.2 Hz, 1H), 7.69-7.65(m, 1H), 7.53(dJ=8.2 Hz, 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 / z 542.86(M + +1).

[0233] Following substantially the same method as in Example 27, the compounds in Table 11 below were synthesized.

[0234] [Table 26]

[0235] Example 81: Synthesis of Compound 81, 5-[3-(1-cyclobutyl-4-piperidyl)-2-fluoro-phenyl]-3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-1,3,4-oxadiazole-2-thione [Step 1] Synthesis of tert-butyl 4-[2-fluoro-3-(2-thioxo-3H-1,3,4-oxadiazol-5-yl)phenyl]piperidine-1-carboxylate [ka]

[0236] A mixture of tert-butyl 4-[2-fluoro-3-(hydrazinecarbonyl)phenyl]piperidine-1-carboxylate (100.00%, 1.100 g, 3.260 mmol) prepared in Step 3 of Example 26 and potassium ethyl xanthate (100.00%, 0.627 g, 3.911 mmol) in ethanol (80 mL) was heated to reflux overnight. After cooling to room temperature, water was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous ammonium chloride and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 24 g cartridge; ethyl acetate / hexane = 0% to 40%) and concentrated to give the title compound (0.9 g, 72.76%, white solid).

[0237] [Step 2] Synthesis of tert-butyl 4-[3-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-thioxo-1,3,4-oxadiazol-2-yl]-2-fluoro-phenyl]piperidine-1-carboxylate [ka]

[0238] A solution of tert-butyl 4-[2-fluoro-3-(2-thioxo-3H-1,3,4-oxadiazol-5-yl)phenyl]piperidine-1-carboxylate (100.00%, 0.500 g, 1.318 mmol) and potassium carbonate (100.00%, 0.196 g, 1.978 mmol) in N,N-dimethylformamide (20 mL) was stirred at room temperature for 30 minutes, and then 2-[6-(bromomethyl)-3-pyridyl]-5-(difluoromethyl)-1,3,4-oxadiazole (100.00%, 0.401 g, 1.383 mmol) and potassium iodide (100.00%, 0.109 g, 0.657 mmol) were added and stirred overnight at the same temperature. Water was poured into the reaction mixture and extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 24 g cartridge; ethyl acetate / hexane = 0% to 30%) and concentrated to give the title compound (0.61 g, 78.64%, white solid).

[0239] [Step 3] Synthesis of 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[2-fluoro-3-(4-piperidyl)phenyl]-1,3,4-oxadiazole-2-thione 2,2,2-trifluoroacetic acid [ka]

[0240] A solution of tert-butyl 4-[3-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-thioxo-1,3,4-oxadiazol-2-yl]-2-fluoro-phenyl]piperidine-1-carboxylate (100.00%, 0.400 g, 0.680 mmol) synthesized in Step 2 and trifluoroacetic acid (100.00%, 0.232 g, 2.035 mmol) dissolved in dichloromethane (20 mL) at room temperature was stirred at the same temperature for 3 hours. After removing the solvent from the reaction mixture under reduced pressure, the resulting product was used without further purification (0.37 g, 90.37%, yellow oil).

[0241] [Step 4] Synthesis of compound 81 [ka]

[0242] 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[2-fluoro-3-(4-piperidyl)phenyl]-1,3,4-oxadiazole-2-thione synthesized in Step 3. A solution of 2,2,2-trifluoroacetic acid (100.00%, 0.050 g, 0.083 mmol), cyclobutanone (100.00%, 0.012 g, 0.171 mmol) and N-ethyldiisopropylamine (100.00% solution, 0.029 mL, 0.167 mmol) in dichloromethane (5 mL) was stirred at room temperature for 30 minutes, and sodium triacetoxyborohydride (100.00%, 0.053 g, 0.250 mmol) was added, followed by additional stirring at the same temperature overnight. Water was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; methanol / dichloromethane = 0% to 5%) and concentrated to give the title compound (0.029 g, 64.40%, white solid).

[0243] 1 H NMR (400 MHz, CDCl3) δ 9.31 (d, J=2.1 Hz, 1H), 8.38 (dd, J=8.2, 2.3 Hz, 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).

[0244] Following substantially the same procedures as in Example 81, the compounds in Table 12 below were synthesized.

[0245] [Table 27]

[0246] Example 100: Synthesis of Compound 100, 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[6-(4-ethylpiperazin-1-yl)-2-pyridyl]-1,3,4-oxadiazole-2-thione [Step 1] Synthesis of tert-butyl 4-(6-methoxycarbonyl-2-pyridyl)piperazine-1-carboxylate [ka]

[0247] A solution of methyl 6-fluoropyridine-2-carboxylate (100.00%, 0.500 g, 3.223 mmol), tert-butyl piperazine-1-carboxylate (100.00%, 1.200 g, 6.443 mmol), and N,N-diisopropylethylamine (100.00% solution, 0.844 mL, 4.800 mmol) in dimethyl sulfoxide (15 mL) was stirred at 130 °C overnight at the same temperature, then cooled to room temperature to terminate the reaction. Water was poured into the reaction mixture and extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride and dried over anhydrous magnesium sulfate, then filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 24 g cartridge; ethyl acetate / hexane = 0% to 60%) and concentrated to give the title compound (0.736 g, 71.05%, yellow solid).

[0248] [Step 2] Synthesis of tert-butyl 4-[6-(hydrazinecarbonyl)-2-pyridyl]piperazine-1-carboxylate [ka]

[0249] To a solution of tert-butyl 4-(6-methoxycarbonyl-2-pyridyl)piperazine-1-carboxylate (100.00%, 0.736 g, 2.290 mmol) synthesized in Step 1 in ethanol (10 mL) at room temperature, hydrazine monohydrate (100.00% solution, 1.113 mL, 22.900 mmol) was added and stirred at 60 °C for 18 hours. The temperature was then lowered to room temperature to complete the reaction. Saturated aqueous ammonium chloride solution was poured into the reaction mixture, which was then extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride solution, removed with anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; methanol / dichloromethane = 0% to 10%) and concentrated to yield the title compound (0.73 g, 99.18%, yellow solid).

[0250] [Step 3] Synthesis of tert-butyl 4-[6-(2-thioxo-3H-1,3,4-oxadiazol-5-yl)-2-pyridyl]piperazine-1-carboxylate [ka]

[0251] A solution of tert-butyl 4-[6-(hydrazinecarbonyl)-2-pyridyl]piperazine-1-carboxylate (100.00%, 0.730 g, 2.271 mmol) synthesized in Step 2 and potassium ethylxanthate (100.00%, 0.364 g, 2.271 mmol) in ethanol (10 mL) was stirred at 90 °C overnight, then the temperature was lowered to room temperature to complete the reaction. Saturated aqueous ammonium chloride was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and dried over anhydrous magnesium sulfate, then filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 40 g cartridge; dichloromethane / methanol = 0% to 10%) and concentrated to yield the title compound (0.604 g, 73.18%, yellow solid).

[0252] [Step 4] Synthesis of tert-butyl 4-[6-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-thioxo-1,3,4-oxadiazol-2-yl]-2-pyridyl]piperazine-1-carboxylate [ka]

[0253] A solution of tert-butyl 4-[3-(2-thioxo-3H-1,3,4-oxadiazol-5-yl)phenyl]piperazine-1-carboxylate (100.00%, 0.700 g, 1.932 mmol), 2-[6-(bromomethyl)-3-pyridyl]-5-(difluoromethyl)-1,3,4-oxadiazole (100.00%, 1.000 equivalents, 1.932 mmol), potassium carbonate (100.00%, 2.000 equivalents, 3.863 mmol), and potassium iodide (100.00%, 2.000 equivalents, 3.863 mmol) in N,N-dimethylformamide (5 mL) was stirred overnight at the same temperature. Water was poured into the reaction mixture, which was then extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride and then filtered with anhydrous magnesium sulfate, then concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 50%) and concentrated to give the title compound (0.14 g, 12.68%, yellow solid).

[0254] [Step 5] Synthesis of 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-(6-piperazin-1-yl-2-pyridyl)-1,3,4-oxadiazole-2-thione [ka]

[0255] A solution of tert-butyl 4-[6-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-thioxo-1,3,4-oxadiazol-2-yl]-2-pyridyl]piperazine-1-carboxylate (100.00%, 0.384 g, 0.671 mmol) synthesized in Step 4 and trifluoroacetic acid (100.00% solution, 0.513 mL, 6.700 mmol) in dichloromethane (3 mL) was stirred at room temperature overnight. Saturated aqueous sodium bicarbonate solution was poured into the reaction mixture and 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 (0.31 g, 97.83%, yellow oil).

[0256] [Step 6] Synthesis of Compound 100 [ka]

[0257] A solution of 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-(6-piperazin-1-yl-2-pyridyl)-1,3,4-oxadiazole-2-thione (100.00%, 0.100 g, 0.212 mmol) synthesized in Step 5, acetaldehyde (100.00% solution, 0.024 mL, 0.429 mmol) and N-ethyl-N-isopropyl-propan-2-amine (100.00% solution, 0.074 mL, 0.425 mmol) in dichloromethane (1 mL) was stirred at room temperature for 30 minutes, sodium triacetoxyborohydride (100.00%, 0.134 g, 0.635 mmol) was added, and the mixture was stirred at the same temperature for an additional 18 hours. Saturated aqueous sodium bicarbonate was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; dichloromethane / methanol = 0% to 10%) and concentrated to give the title compound (0.026 g, 24.55%, yellow solid).

[0258] 1 H NMR (400 MHz, CDCl3)δ 9.32(d, J=1.6 Hz, 1H), 8.37(dd, J=8.2, 2.2 Hz, 1H), 7.84(d, J=8.4 Hz, 1H), 7.63-7.59(m, 1H), 7.43(d, J=7.2 Hz, 1H), 6.96(t, J=51.6 Hz, 1H), 6.78(d, J=8.8 Hz, 1H), 4.75(s, 2H), 3.69(t, J=5.0 Hz, 4H), 2.59(t, J=5.0 Hz, 4H), 2.50(q, J=7.2 Hz, 2H), 1.16(t, J=7.2 Hz, 3H); LRMS(ES)m / z 501.5(M + +1).

[0259] Following substantially the same procedures as in Example 100, the compounds in Table 13 below were synthesized.

[0260] [Table 28] [Table 29]

[0261] Example 41: Synthesis of Compound 41, 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[2-fluoro-3-(1-methyl-4-piperidyl)phenyl]-1,3,4-thiadiazol-2-one [Step 1] Synthesis of tert-butyl 4-[3-(aminocarbamothioyl)-2-fluoro-phenyl]piperidine-1-carboxylate [ka]

[0262] A solution of tert-butyl 4-[2-fluoro-3-(hydrazinecarbonyl)phenyl]piperidine-1-carboxylate (100.00%, 0.200 g, 0.593 mmol) prepared in Step 3 of Example 26 and Lawesson's reagent (100.00%, 0.288 g, 0.712 mmol) in toluene (20 mL) was stirred at room temperature overnight. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous ammonium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The resulting product was used without further purification (0.11 g, 52.51%, yellow oil).

[0263] [Step 2] Synthesis of tert-butyl 4-[2-fluoro-3-(2-oxo-3H-1,3,4-thiadiazol-5-yl)phenyl]piperidine-1-carboxylate [ka]

[0264] A solution of tert-butyl 4-[3-(aminocarbamothioyl)-2-fluorophenyl]piperidine-1-carboxylate (100.00%, 0.200 g, 0.566 mmol) synthesized in Step 1 and 1,1'-carbonylbis-1H-imidazole (100.00%, 0.110 g, 0.678 mmol) in dichloromethane (20 mL) was stirred at room temperature overnight. Water was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous ammonium chloride and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 40%) and concentrated to give the title compound (0.15 g, 69.86%, white solid).

[0265] [Step 3] Synthesis of tert-butyl 4-[3-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-oxo-1,3,4-thiadiazol-2-yl]-2-fluoro-phenyl]piperidine-1-carboxylate [ka]

[0266] To a solution of tert-butyl 4-[2-fluoro-3-(2-oxo-3H-1,3,4-thiadiazol-5-yl)phenyl]piperidine-1-carboxylate (100.00%, 0.073 g, 0.192 mmol) and potassium carbonate (100.00%, 0.029 g, 0.293 mmol) in N,N-dimethylformamide (20 mL) at room temperature, 2-[6-(bromomethyl)-3-pyridyl]-5-(difluoromethyl)-1,3,4-oxadiazole (100.00%, 0.059 g, 0.203 mmol) and potassium iodide (100.00%, 0.016 g, 0.096 mmol) were added and stirred at the same temperature for 30 minutes. Water was poured into the reaction mixture and extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 30%) and concentrated to give the title compound (0.05 g, 44.15%, white solid).

[0267] [Step 4] Synthesis of 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[2-fluoro-3-(4-piperidyl)phenyl]-1,3,4-thiadiazol-2-one 2,2,2-trifluoroacetic acid [ka]

[0268] A solution of tert-butyl 4-[3-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-oxo-1,3,4-thiadiazol-2-yl]-2-fluoro-phenyl]piperidine-1-carboxylate (100.00%, 0.058 g, 0.099 mmol) synthesized in Step 3 and trifluoroacetic acid (100.00%, 0.034 g, 0.298 mmol) in dichloromethane (10 mL) was stirred at the same temperature for 3 hours. After removing the solvent from the reaction mixture under reduced pressure, the resulting product was used without further purification (0.055 g, 92.64%, yellow oil).

[0269] [Step 5] Synthesis of compound 41 [ka]

[0270] A solution of 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[2-fluoro-3-(4-piperidyl)phenyl]-1,3,4-thiadiazol-2-one (100.00%, 0.055 g, 0.091 mmol), N-ethyldiisopropylamine (100.00% solution, 0.032 mL, 0.184 mmol), formaldehyde (100.00%, 0.005 g, 0.167 mmol), and sodium triacetoxyborohydride (100.00%, 0.039 g, 0.184 mmol) in dichloromethane (5 mL) was stirred overnight at the same temperature. Water was poured into the reaction mixture, which was then extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium bicarbonate and then filtered with anhydrous magnesium sulfate, then concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; methanol / dichloromethane = 0% to 5%) and concentrated to give the title compound (0.031 g, 67.58%, white solid).

[0271] 1H NMR (400 MHz, CDCl3)δ 9.32(d, J=1.6 Hz, 1H), 8.41(dd, J=8.2, 2.2 Hz, 1H), 7.77-7.73(m, 1H), 7.46(d, J=8.2 Hz, 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).

[0272] Following substantially the same method as in Example 41, the compounds in Table 14 below were synthesized.

[0273] [Table 30]

[0274] Example 20: Synthesis of Compound 20, 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-(4-piperazin-1-ylphenyl)-1,3,4-oxadiazol-2-one [Step 1] Synthesis of tert-butyl 4-(4-methoxycarbonylphenyl)piperazine-1-carboxylate [ka]

[0275] A solution of methyl 4-bromobenzoate (100.00%, 0.500 g, 2.325 mmol), tert-butyl piperazine-1-carboxylate (100.00%, 1.200 equiv, 2.790 mmol), tris(dibenzylideneacetone)dipalladium (100.00%, 5.000 mol%, 0.116 mmol), Xphos (100.00%, 5.000 mol%, 0.116 mmol), and cesium carbonate (100.00%, 2.000 equiv, 4.650 mmol) in toluene (50 mL) at 110 °C was stirred overnight at the same temperature and then cooled to room temperature to terminate the reaction. Water was poured into the reaction mixture, which was then extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, removed with anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 30%) and concentrated to give the title compound (0.73 g, 97.99%, brown solid).

[0276] [Step 2] Synthesis of tert-butyl 4-[4-(hydrazinecarbonyl)phenyl]piperazine-1-carboxylate [ka]

[0277] A solution of tert-butyl 4-(4-methoxycarbonylphenyl)piperazine-1-carboxylate (100.00%, 0.770 g, 2.403 mmol) synthesized in Step 1 and hydrazine monohydrate (100.00%, 10.000 equivalents, 24.030 mmol) in dichloromethane (5 mL) 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 and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 30%) and concentrated to give the title compound (0.77 g, 100.0%, yellow solid).

[0278] [Step 3] Synthesis of tert-butyl 4-[4-(2-oxo-3H-1,3,4-oxadiazol-5-yl)phenyl]piperazine-1-carboxylate [ka]

[0279] A solution of tert-butyl 4-[4-(hydrazinecarbonyl)phenyl]piperazine-1-carboxylate (100.00%, 0.770 g, 2.403 mmol) synthesized in Step 2 and 1,1'-carbonylbis-1H-imidazole (100.00%, 1.500 equiv., 3.605 mmol) in dichloromethane (5 mL) was heated to reflux overnight and then cooled to room temperature to complete the reaction. Water was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 100%) and concentrated to yield the title compound (0.5 g, 60.06%, yellow solid).

[0280] [Step 4] Synthesis of tert-butyl 4-[4-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-oxo-1,3,4-oxadiazol-2-yl]phenyl]piperazine-1-carboxylate [ka]

[0281] A 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), 2-[6-(bromomethyl)-3-pyridyl]-5-(difluoromethyl)-1,3,4-oxadiazole (100.00%, 1.200 equivalents, 1.732 mmol), potassium carbonate (100.00%, 2.000 equivalents, 2.887 mmol), and potassium iodide (100.00%, 1.100 equivalents, 1.588 mmol) in N,N-dimethylformamide (25 mL) was stirred at room temperature. Water was poured into the reaction mixture, which was then extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 50%) and concentrated to give the title compound (0.9 g, 112.2%, yellow solid).

[0282] [Step 5] Synthesis of Compound 20, 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-(4-piperazin-1-ylphenyl)-1,3,4-oxadiazol-2-one [ka]

[0283] A solution of tert-butyl 4-[4-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-oxo-1,3,4-oxadiazol-2-yl]phenyl]piperazine-1-carboxylate (100.00%, 0.900 g, 1.620 mmol) synthesized in Step 4 and 2,2,2-trifluoroacetic acid (100.00%, 10.000 equivalents, 16.200 mmol) in dichloromethane (50 mL) was stirred at the same temperature. Aqueous sodium bicarbonate was poured into the reaction mixture, and the mixture was extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; dichloromethane / methanol = 0% to 10%) and concentrated to give the title compound (0.12 g, 16.26%, white solid).

[0284] 1 H NMR (400 MHz, CDCl3)δ 9.29(s, 1H), 8.39(d, J=10.0 Hz, 1H), 7.70(d, J=8.8 Hz, 2H), 7.49(d, J=8.0 Hz, 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).

[0285] Following substantially the same method as in Example 20, the compounds in Table 15 below were synthesized.

[0286] [Table 31]

[0287] Example 21: Synthesis of Compound 21, 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[4-(4-methylpiperazin-1-yl)phenyl]-1,3,4-oxadiazol-2-one [ka]

[0288] A solution of 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-(4-piperazin-1-ylphenyl)-1,3,4-oxadiazol-2-one (100.00%, 0.060 g, 0.132 mmol) synthesized in Step 5 of Example 20, sodium triacetoxyborohydride (100.00%, 2.000 equivalents, 0.264 mmol), and formaldehyde (37.00%, 2.000 equivalents, 0.264 mmol) in dichloromethane (5 mL) 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, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; dichloromethane / methanol = 0% to 10%) and concentrated to give the title compound (0.025 g, 40.42%, yellow solid).

[0289] 1 H NMR (400 MHz, CDCl3)δ 9.29(s, 1H), 8.39(d, J=10.4 Hz, 1H), 7.70(d, J=8.8 Hz, 2H), 7.50(d, J=8.0 Hz, 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).

[0290] Following substantially the same method as in Example 21, the compounds in Table 16 below were synthesized.

[0291] [Table 32] [Table 33]

[0292] Example 6 Synthesis of Compound 6, 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-[6-(4-isopropylpiperazin-1-yl)-2-pyridyl]-1,3,4-oxadiazol-2-one [Step 1] Synthesis of 6-fluoropyridine-2-carbohydrazide [ka]

[0293] Hydrazine monohydrate (100.00% solution, 6.266 mL, 129.000 mmol) was added to a solution of methyl 6-fluoropyridine-2-carboxylate (100.00%, 1.000 g, 6.446 mmol) in ethanol (30 mL) at room temperature, and the mixture was stirred overnight at the same temperature. The solvent was removed from the reaction mixture under reduced pressure, and the resulting concentrate was poured into saturated aqueous sodium bicarbonate and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, 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).

[0294] [Step 2] Synthesis of 5-(6-fluoro-2-pyridyl)-3H-1,3,4-oxadiazol-2-one [ka]

[0295] To a solution of 6-fluoropyridine-2-carbohydrazide (100.00%, 1.000 g, 6.446 mmol) synthesized in Step 1 and 1,1'-carbonylbis-1H-imidazole (100.00%, 1.254 g, 7.734 mmol) in tetrahydrofuran (30 mL) at room temperature, triethylamine (100.00% solution, 1.251 mL, 9.000 mmol) was added and stirred at the same temperature overnight. Water was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; methanol / dichloromethane = 0% to 10%) and concentrated to give the title compound (0.21 g, 17.987%, yellow solid).

[0296] [Step 3] Synthesis of 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-(6-fluoro-2-pyridyl)-1,3,4-oxadiazol-2-one [ka]

[0297] 5-(6-fluoro-2-pyridyl)-3H-1,3,4-oxadiazol-2-one (100.00%, 0.210 g, 1.160 mmol) synthesized in Step 2 and potassium carbonate (100.00%, 0.244 g, 1.765 mmol) were dissolved in N,N-dimethylformamide (5 mL) at room temperature. 2-[6-(bromomethyl)-3-pyridyl]-5-(difluoromethyl)-1,3,4-oxadiazole (100.00%, 0.404 g, 1.393 mmol) was added and stirred at the same temperature overnight. Water was poured into the reaction mixture, which was then extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; methanol / dichloromethane = 0% to 10%) and concentrated to give the title compound (0.185 g, 40.88%, pale yellow solid).

[0298] [Step 4] Synthesis of Compound 6 [ka]

[0299] A solution of 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-(6-fluoro-2-pyridyl)-1,3,4-oxadiazol-2-one (100.00%, 0.040 g, 0.103 mmol) synthesized in Step 3, 1-isopropylpiperazine (100.00% solution, 0.029 mL, 0.203 mmol), and N,N-diisopropylethylamine (100.00% solution, 0.027 mL, 0.150 mmol) in dimethyl sulfoxide (1 mL) at 130 °C was stirred overnight at the same temperature and then cooled to room temperature to complete the reaction. Water was poured into the reaction mixture and extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride and dried over anhydrous magnesium sulfate, then filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; methanol / dichloromethane = 0% to 10%) and concentrated to give the title compound (0.02 g, 39.15%) in the form of an orange solid.

[0300] 1 H NMR (400 MHz, CDCl3)δ 9.32(d, J=1.6 Hz, 1H), 8.43(dd, J=8.2, 2.2 Hz, 1H), 7.61-7.57(m, 1H), 7.52(d, J=8.0 Hz, 1H), 7.23(d, J=7.6 Hz, 1H), 6.96(t, J=51.6 Hz, 1H), 6.78(d, J=8.8 Hz, 1H), 5.27(s, 2H), 3.76(s, 4H), 2.89-2.75(m, 5H), 1.18(d, J=5.6 Hz, 6H);LRMS(ES)m / z 499.8(M + +1).

[0301] Following substantially the same method as in Example 6, the compounds in Table 17 below were synthesized.

[0302] [Table 34]

[0303] 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-oxadiazole-2(3H)-thione [Step 1] Synthesis of methyl 1-methylindole-5-carboxylate [ka]

[0304] To a solution of methyl 1H-indole-5-carboxylate (100.00%, 0.500 g, 2.854 mmol) in N,N-dimethylformamide (7 mL) at 0 °C, sodium hydride (60.00%, 140.000 mg, 3.500 mmol) was added and stirred at the same temperature for 0.2 h. Iodomethane (100.00% solution, 0.27 mL, 4.340 mmol) was added to the reaction mixture, and the mixture was stirred at room temperature for an additional 4 h. 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 and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 30%) and concentrated to give the title compound (0.27 g, 49.996%, white solid).

[0305] [Step 2] Synthesis of 1-methylindole-5-carbohydrazide [ka]

[0306] Methyl 1-methylindole-5-carboxylate (100.00%, 160.000 mg, 0.846 mmol) synthesized in Step 1 was dissolved in ethanol (2.5 mL), and hydrazine monohydrate (100.00% solution, 0.8 mL, 16.490 mmol) was added at room temperature. The mixture was stirred at 60 °C for 18 hours, and then the temperature was lowered to room temperature to complete the reaction. The solvent was removed from the reaction mixture under reduced pressure, and the resulting product (160 mg, 100.00%, pale yellow solid) was used without further purification.

[0307] [Step 3] Synthesis of 5-(1-methylindol-5-yl)-3H-1,3,4-oxadiazol-2-one [ka]

[0308] To a solution of 1-methylindole-5-carbohydrazide (100.00%, 160.000 mg, 0.846 mmol) synthesized in Step 2 and N,N-diisopropylethylamine (DIPEA, 100.00% solution, 0.3 mL, 1.700 mmol) in dichloromethane (3 mL) at 0 °C, triphosgene (100.00%, 100.000 mg, 0.337 mmol) was added and stirred at the same temperature. The reaction mixture was evaporated under reduced pressure, and the concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 10% to 50%) and concentrated to give the title compound (270 mg, 148.36%, white solid).

[0309] [Step 4] Synthesis of compound 19 [ka]

[0310] To a solution of 5-(1-methylindol-5-yl)-3H-1,3,4-oxadiazol-2-one (100.00%, 50.000 mg, 0.232 mmol) synthesized in Step 3 in N,N-dimethylformamide (2 mL) at room temperature, potassium carbonate (100.00%, 35.000 mg, 0.353 mmol) was added and stirred at the same temperature for 0.3 hours. 2-[6-(bromomethyl)-3-pyridyl]-5-(difluoromethyl)-1,3,4-oxadiazole (100.00%, 80.000 mg, 0.276 mmol) was added to the reaction mixture, which was then stirred at 35°C for an additional 18 hours. A saturated aqueous solution of sodium chloride was poured into the reaction mixture, which was then extracted with ethyl acetate. The organic layer was washed with a saturated aqueous solution of sodium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; hexane / ethyl acetate = 100% to 50%) and concentrated to give the title compound (43 mg, 43.61%, white solid).

[0311] 1 H NMR (400 MHz, CD3OD)δ 9.27(d, J=1.2 Hz, 1H), 8.52(dd, J=8.4, 2.4 Hz, 1H), 8.10(d, J=0.8 Hz, 1H), 7.80(s, 1H), 7.70(t, J=8.8 Hz, 1H), 7.48(d, J=8.8 Hz, 1H), 7.26(d, J=3.2 Hz, 1H), 7.21(t, J=51.6 Hz, 1H), 6.57(dd, J=3.2, 0.4 Hz, 1H), 5.25(s, 2H), 3.86(s, 3H);LRMS(ES)m / z 425.7(M + +1).

[0312] Following substantially the same method as in Example 19, the compounds in Table 18 below were synthesized.

[0313] [Table 35]

[0314] Example 33: Synthesis of Compound 33, 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-(1H-indol-6-yl)-1,3,4-oxadiazol-2-one [Step 1] Synthesis of 1-tert-butoxycarbonylindole-6-carboxylic acid [ka]

[0315] 4-(Dimethylamino)pyridine (100.00%, 0.150 g, 1.228 mmol) was added to a solution of 1H-indole-6-carboxylic acid (100.00%, 1.000 g, 6.205 mmol) and di-tert-butyl dicarbonate (100.00%, 2.000 g, 9.164 mmol) in tetrahydrofuran (12 mL) at room temperature, and the mixture was stirred at the same temperature for 18 hours. Water was added to the reaction mixture, which was then extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 24 g cartridge; ethyl acetate / hexane = 0% to 30%) and concentrated to give the title compound (0.8 g, 49.34%, white solid).

[0316] [Step 2] Synthesis of tert-butyl 6-(hydrazinecarbonyl)-1H-indole-1-carboxylate [ka]

[0317] 1-tert-Butoxycarbonylindole-6-carboxylic acid (100.00%, 250 mg, 0.9568 mmol) synthesized in Step 1 was dissolved in tetrahydrofuran (5 mL) at room temperature, to which 1,1'-carbonylbis-1H-imidazole (100.00%, 200.000 mg, 1.233 mmol) was added and stirred at the same temperature for 3 hours. Hydrazine monohydrate (100.00%, 145.000 mg, 2.897 mmol) was added to the reaction mixture, and the mixture was stirred at the same temperature for an additional 18 hours. The solvent was removed from the reaction mixture under reduced pressure, and the resulting product was used without further purification (mixture, pale yellow solid).

[0318] [Step 3] Synthesis of tert-butyl 6-(2-oxo-3H-1,3,4-oxadiazol-5-yl)indole-1-carboxylate [ka]

[0319] tert-Butyl 6-(hydrazinecarbonyl)indole-1-carboxylate (100.00%, 450.000 mg, 1.635 mmol) synthesized in Step 2 and N,N-diisopropylethylamine (100.00% solution, 0.56 mL, 3.200 mmol) were dissolved in dichloromethane (5 mL). Triphosgene (100.00%, 190.000 mg, 0.640 mmol) was added at 0 °C and the mixture was stirred at room temperature for 18 h. The solvent was removed from the reaction mixture under reduced pressure, and the concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 10% to 50%) and concentrated to give the title compound (270 mg, 54.82%, white solid).

[0320] [Step 4] Synthesis of tert-butyl 6-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-oxo-1,3,4-oxadiazol-2-yl]indole-1-carboxylate [ka]

[0321] To a solution of tert-butyl 6-(2-oxo-3H-1,3,4-oxadiazol-5-yl)indole-1-carboxylate (100.00%, 55.000 mg, 0.183 mmol) synthesized in Step 3 in N,N-dimethylformamide (2 mL) at room temperature, potassium carbonate (100.00%, 25.000 mg, 0.252 mmol) was added and stirred at the same temperature for 0.3 hours. 2-[6-(bromomethyl)-3-pyridyl]-5-(difluoromethyl)-1,3,4-oxadiazole (100.00%, 64.000 mg, 0.221 mmol) was added to the reaction mixture, which was then stirred at 35°C for an additional 18 hours. Water was poured into the reaction mixture, which was then extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; hexane / ethyl acetate = 100% to 50%) and concentrated to give the title compound (58 mg, 62.25%, white solid).

[0322] [Step 5] Synthesis of compound 33 [ka]

[0323] To a solution of tert-butyl 6-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-oxo-1,3,4-oxadiazol-2-yl]indole-1-carboxylate (100.00%, 50.000 mg, 0.098 mmol) synthesized in Step 4 in dichloromethane (1 mL) at room temperature, trifluoroacetic acid (100.00% solution, 0.3 mL, 3.918 mmol) was added and stirred at the same temperature for 1 hour. The solvent was removed from the reaction mixture under reduced pressure, and the resulting concentrate was poured into saturated aqueous sodium bicarbonate and extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride and dried over anhydrous magnesium sulfate, then filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; dichloromethane / methanol = 100% to 80%) and concentrated to give the title compound (34 mg, 84.59%, pale yellow solid).

[0324] 1 H NMR (400 MHz, CD3OD)δ 9.27(d, J=1.6 Hz, 1H), 8.54(dd, J=8.2, 2.2 Hz, 1H), 7.93(d, J=0.8 Hz, 1H), 7.73(d, J=8.4 Hz, 1H), 7.67(d, J=8.4 Hz, 1H), 7.53(dd, J=8.4, 1.6 Hz, 1H), 7.44(d, J=1.2 Hz, 1H), 7.26(t, J=51.6 Hz, 1H), 5.26(s, 2H); LRMS(ES)m / z 412.8(M + +1).

[0325] Following substantially the same method as in Example 33, the compounds in Table 19 below were synthesized.

[0326] [Table 36]

[0327] Example 11: Synthesis of Compound 11, 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-(1,2,3,4-tetrahydroisoquinolin-6-yl)-1,3,4-oxadiazol-2-one [Step 1] Synthesis of tert-butyl 7-(hydrazinecarbonyl)-3,4-dihydro-1H-isoquinoline-2-carboxylate [ka]

[0328] A solution of 2-tert-butyl, 7-methyl-3,4-dihydro-1H-isoquinoline-2,7-dicarboxylate (100.00%, 0.603 g, 2.070 mmol) and hydrazine monohydrate (100.00%, 10.000 equivalents, 20.700 mmol) in ethanol (20 mL) at 70 °C was stirred overnight at the same temperature, then cooled to room temperature to complete the reaction. The solvent was removed from the reaction mixture under reduced pressure, and the resulting material was used without further purification (0.603 g, 100.0%, white solid).

[0329] [Step 2] Synthesis of tert-butyl 7-(2-oxo-3H-1,3,4-oxadiazol-5-yl)-3,4-dihydro-1H-isoquinoline-2-carboxylate [ka]

[0330] A solution of tert-butyl 7-(hydrazinecarbonyl)-3,4-dihydro-1H-isoquinoline-2-carboxylate (100.00%, 0.640 g, 2.197 mmol) synthesized in Step 1 and 1,1'-carbonylbis-1H-imidazole (100.00%, 1.500 equiv., 3.296 mmol) in dichloromethane (5 mL) was stirred at 50 °C overnight at the same temperature and then cooled to room temperature to complete the reaction. Water was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; ethyl acetate / hexane = 0% to 100%) and concentrated to yield the title compound (0.42 g, 60.25%, white solid).

[0331] [Step 3] Synthesis of tert-butyl 7-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-oxo-1,3,4-oxadiazol-2-yl]-3,4-dihydro-1H-isoquinoline-2-carboxylate [ka]

[0332] A solution of tert-butyl 7-(2-oxo-3H-1,3,4-oxadiazol-5-yl)-3,4-dihydro-1H-isoquinoline-2-carboxylate (100.00%, 0.420 g, 1.324 mmol), 2-[6-(bromomethyl)-3-pyridyl]-5-(difluoromethyl)-1,3,4-oxadiazole (100.00%, 1.200 equivalents, 1.588 mmol), potassium carbonate (100.00%, 2.000 equivalents, 2.647 mmol), and potassium iodide (100.00%, 1.100 equivalents, 1.456 mmol) in N,N-dimethylformamide (25 mL) was stirred overnight at the same temperature. Water was poured into the reaction mixture, which was then extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and then filtered with anhydrous magnesium sulfate, then concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 100%) and concentrated to give the title compound (0.55 g, 78.92%, yellow solid).

[0333] [Step 4] Synthesis of compound 11 [ka]

[0334] A solution of tert-butyl 7-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-oxo-1,3,4-oxadiazol-2-yl]-3,4-dihydro-1H-isoquinoline-2-carboxylate (100.00%, 0.550 g, 1.045 mmol) synthesized in Step 3 and 2,2,2-trifluoroacetic acid (100.00%, 10.000 equivalents, 10.450 mmol) in dichloromethane (20 mL) was stirred at room temperature overnight. Aqueous sodium bicarbonate was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; dichloromethane / methanol = 0% to 10%) and concentrated to give the title compound (0.42 g, 94.29%, yellow solid).

[0335] 1 H NMR (400 MHz, CDCl3)δ 9.31(s, 1H), 8.42(d, J=8.4 Hz, 1H), 7.60(s, 2H), 7.51(d, J=7.6 Hz, 1H), 7.12(d, J=8.4 Hz, 1H), 6.93(t, J=51.6 Hz, 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).

[0336] Example 12: Synthesis of Compound 12, 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-(2-methyl-3,4-dihydro-1H-isoquinolin-7-yl)-1,3,4-oxadiazol-2-one [ka]

[0337] A solution of 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-(1,2,3,4-tetrahydroisoquinolin-7-yl)-1,3,4-oxadiazol-2-one (100.00%, 0.080 g, 0.188 mmol) synthesized in Step 4 of Example 11, formaldehyde (100.00%, 1.500 equiv., 0.281 mmol), and sodium triacetoxyborohydride (100.00%, 2.000 equiv., 0.375 mmol) in dichloromethane (5 mL) was stirred at room temperature overnight. Water was poured into the reaction mixture, which was then extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; dichloromethane / methanol = 0% to 10%) and concentrated to give the title compound (0.02 g, 24.21%, yellow solid).

[0338] 1 H NMR (400 MHz, CDCl3)δ 9.27(s, 1H), 8.38(d, J=10.4 Hz, 1H), 7.57(d, J=8.0 Hz, 1H), 7.52(d, J=25.6 Hz, 2H), 7.17(d, J=8.0 Hz, 1H), 6.93(t, J=51.6 Hz, 1H), 5.18(s, 2H), 3.60(s, 2H), 2.95(t, J=5.6 Hz, 2H), 2.72(t, J=6.0 Hz, 2H), 2.45(s, 3H); LRMS(ES)m / z 441.4(M + +1).

[0339] Following substantially the same method as in Example 12, the compounds in Table 20 below were synthesized.

[0340] [Table 37]

[0341] Example 135: Synthesis of Compound 135, 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-3-fluoro-2-pyridyl]methyl]-5-(2-methyl-3,4-dihydro-1H-isoquinolin-6-yl)-1,3,4-oxadiazole-2-thione [Step 1] Synthesis of tert-butyl 6-(hydrazinecarbonyl)-3,4-dihydro-1H-isoquinoline-2-carboxylate [ka]

[0342] To a solution of 2-tert-butyl, 6-methyl-3,4-dihydro-1H-isoquinoline-2,6-dicarboxylate (100.00%, 1.000 g, 3.433 mmol) in ethanol (20 mL) at room temperature, hydrazine monohydrate (100.00% solution, 1.668 mL, 34.320 mmol) was added and stirred at 60 °C overnight. The reaction was then cooled to room temperature to terminate the reaction. The solvent was removed from the reaction mixture under reduced pressure, and the concentrate was purified by column chromatography (SiO2, 24 g cartridge; methanol / dichloromethane = 0% to 10%) and concentrated to give the title compound (1 g, 100.0%, white solid).

[0343] [Step 2] Synthesis of tert-butyl 6-(2-thioxo-3H-1,3,4-oxadiazol-5-yl)-3,4-dihydro-1H-isoquinoline-2-carboxylate [ka]

[0344] A solution of tert-butyl 6-(hydrazinecarbonyl)-3,4-dihydro-1H-isoquinoline-2-carboxylate (100.00%, 0.642 g, 2.204 mmol) synthesized in Step 1 and potassium ethyl xanthate (100.00%, 0.353 g, 2.202 mmol) in ethanol (10 mL) was stirred at 90 °C overnight, then the temperature was lowered to room temperature to complete the reaction. Saturated aqueous ammonium chloride was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; dichloromethane / methanol = 0% to 10%) and concentrated to yield the title compound (0.03 g, 4.083%, colorless oil).

[0345] [Step 3] Synthesis of tert-butyl 6-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-3-fluoro-2-pyridyl]methyl]-5-oxo-1,3,4-oxadiazol-2-yl]-3,4-dihydro-1H-isoquinoline-2-carboxylate [ka]

[0346] To a solution of tert-butyl 6-(2-thioxo-3H-1,3,4-oxadiazol-5-yl)-3,4-dihydro-1H-isoquinoline-2-carboxylate (100.00%, 0.550 g, 1.650 mmol) synthesized in Step 2 and potassium carbonate (100.00%, 0.229 g, 2.311 mmol) in N,N-dimethylformamide (10 mL) at room temperature, 2-[6-(bromomethyl)-5-fluoro-3-pyridyl]-5-(difluoromethyl)-1,3,4-oxadiazole (100.00%, 0.610 g, 1.980 mmol) was added and stirred at the same temperature overnight. Water was poured into the reaction mixture, which was then extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; ethyl acetate / hexane = 0% to 60%) and concentrated to give the title compound (0.395 g, 42.71%, yellow solid).

[0347] [Step 4] Synthesis of 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-3-fluoro-2-pyridyl]methyl]-5-(1,2,3,4-tetrahydroisoquinolin-6-yl)-1,3,4-oxadiazole-2-thione [ka]

[0348] A solution of tert-butyl 6-[4-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-3-fluoro-2-pyridyl]methyl]-5-thioxo-1,3,4-oxadiazol-2-yl]-3,4-dihydro-1H-isoquinoline-2-carboxylate (100.00%, 0.395 g, 0.705 mmol) synthesized in Step 3 and trifluoroacetic acid (100.00% solution, 0.539 mL, 7.040 mmol) in dichloromethane (5 mL) was stirred at room temperature overnight. Aqueous sodium bicarbonate was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride, 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).

[0349] [Step 5] Synthesis of Compound 135 [ka]

[0350] 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-3-fluoro-2-pyridyl]methyl]-5-(1,2,3,4-tetrahydroisoquinolin-6-yl)-1,3,4-oxadiazole-2-thione (100.00%, 0.060 g, 0.130 mmol) synthesized in Step 4, formaldehyde (37.00% solution, 0.026 A solution of N-ethyl-N-isopropyl-propan-2-amine (100.00% solution, 0.045 mL, 0.258 mmol) in dichloromethane (1 mL) was stirred at room temperature for 30 minutes, and sodium triacetoxyborohydride (100.00%, 0.082 g, 0.389 mmol) was added. The mixture was stirred at the same temperature for an additional 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 and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; dichloromethane / methanol = 0% to 10%) and concentrated to give the title compound (0.021 g, 33.96%, pale yellow solid).

[0351] 1 H NMR (400 MHz, CDCl3)δ 9.12(s, 1H), 8.15(dd, J=9.0, 1.8 Hz, 1H), 7.79-7.76(m, 2H), 7.17(d, J=8.0 Hz, 1H), 6.96(t, J=52.2 Hz, 1H), 4.80(d, J=1.6 Hz, 2H), 3.65(s, 2H), 3.01(t, J=5.8 Hz, 2H), 2.76-2.73(m, 2H), 2.50(s, 3H); LRMS(ES)m / z 475.9(M + +1).

[0352] Following substantially the same procedures as in Example 135, the compounds in Table 21 below were synthesized.

[0353] [Table 38]

[0354] Example 69: Synthesis of Compound 69, 3-[[5-[5-(difluoromethyl)-1,3,4-oxadiazol-2-yl]-2-pyridyl]methyl]-5-(2-thienyl)-6H-1,3,4-oxadiazin-2-one [Step 1] Synthesis of [2-oxo-2-(2-thienyl)ethyl]acetate [ka]

[0355] To a solution of 2-bromo-1-(2-thienyl)ethanone (100.00%, 0.500 g, 2.438 mmol) in N,N-dimethylformamide (10 mL) at room temperature, potassium acetate (100.00%, 0.718 g, 7.316 mmol) and potassium iodide (100.00%, 0.405 g, 2.440 mmol) were added and stirred at the same temperature for 18 hours. Water was poured into the reaction mixture and extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The resulting product was used without further purification (0.445 g, 99.078%, yellow oil).

[0356] [Step 2] Synthesis of [(2E)-2-(methoxycarbonylhydrazono)-2-(2-thienyl)ethyl]acetate [ka]

[0357] To a solution of [2-oxo-2-(2-thienyl)ethyl]acetate (100.00%, 0.445 g, 2.416 mmol) synthesized in Step 1 and hydrogen chloride (1.00 M solution, 0.048 mL, 0.048 mmol) in methanol (10 mL) at room temperature, methyl hydrazinocarboxylate (100.00%, 0.239 g, 2.653 mmol) was added and stirred at the same temperature for 18 hours. Water was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 50%) and concentrated to give the title compound (0.425 g, 68.648%, yellow solid).

[0358] [Step 3] Synthesis of 5-(2-thienyl)-3,6-dihydro-1,3,4-oxadiazin-2-one [ka]

[0359] A solution of [(2E)-2-(methoxycarbonylhydrazono)-2-(2-thienyl)ethyl]acetate (100.00%, 0.425 g, 1.658 mmol) synthesized in Step 2 and sodium ethoxide (ca. 20% in ethanol, 20.00% solution, 0.962 mL, 2.500 mmol) in ethanol (10 mL) was stirred at room temperature for 30 minutes. Saturated aqueous ammonium chloride was poured into the reaction mixture and extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and then dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 12 g cartridge; ethyl acetate / hexane = 0% to 30%) and concentrated to give the title compound (0.2 g, 66.192%, yellow solid).

[0360] [Step 4] Synthesis of compound 69 [ka]

[0361] A solution of 5-(2-thienyl)-3,6-dihydro-1,3,4-oxadiazin-2-one (100.00%, 0.045 g, 0.247 mmol), 2-[6-(bromomethyl)-3-pyridyl]-5-(difluoromethyl)-1,3,4-oxadiazole (100.00%, 0.075 g, 0.259 mmol), potassium carbonate (100.00%, 0.037 g, 0.373 mmol), and potassium iodide (100.00%, 0.020 g, 0.120 mmol) in N,N-dimethylformamide (1 mL) was stirred overnight at the same temperature. Water was poured into the reaction mixture, which was then extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; ethyl acetate / hexane = 0% to 60%) and concentrated to give the title compound (0.042 g, 43.45%, pale yellow solid).

[0362] 1 H NMR(400 MHz, CDCl3)δ 9.32(d, J=1.6 Hz, 1H), 8.40(dd, J=8.2, 2.2 Hz, 1H), 7.53(d, J=8.4 Hz, 1H), 7.47(dd, J=5.2, 1.2 Hz, 1H), 7.25-7.24(m, 1H), 7.11-7.09(m, 1H), 6.96(t, J=51.6 Hz, 1H), 5.27(s, 2H), 5.25(s, 2H); LRMS(ES)m / z 392.3(M + +1).

[0363] Following substantially the same procedures as in Example 69, the compounds in Table 22 below were synthesized.

[0364] [Table 39]

[0365] 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] Synthesis of methyl 6-(((tert-butoxycarbonyl)amino)methyl)nicotinate [ka]

[0366] To a solution of methyl 6-(aminomethyl)nicotinate (2.000 g, 12.035 mmol) in dichloromethane (20 mL) at room temperature, di-tert-butyl dicarbonate (3.152 g, 14.442 mmol) and triethylamine (2.516 mL, 18.053 mmol) were added and stirred at the same temperature for 18 hours. Water was poured into the reaction mixture, which was then extracted with dichloromethane. The organic layer was washed with saturated aqueous sodium chloride and then dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 24 g cartridge; ethyl acetate / hexane = 0% to 40%) and concentrated to give the title compound (1.700 g, 53.0%, white solid).

[0367] [Step 2] Synthesis of methyl 6-(((tert-butoxycarbonyl)(phenylethynyl)amino)methyl)nicotinate [ka]

[0368] (Bromoethynyl)benzene (0.200 g, 1.105 mmol) was dissolved in toluene (5 mL), and methyl 6-(((tert-butoxycarbonyl)amino)methyl)nicotinate (0.353 g, 1.326 mmol) synthesized in Step 1, 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. The mixture was stirred at 80° C. for 36 hours, and then the temperature was lowered to room temperature to complete the reaction. The reaction mixture was filtered through a Celite pad, and the filtrate from which the solids were removed was subjected to reduced pressure to remove the solvent. The concentrate was then purified by column chromatography (SiO, 12 g cartridge; ethyl acetate / hexane = 0% to 70%) and concentrated to give the title compound (0.110 g, 27.2%, pale yellow solid).

[0369] [Step 3] Synthesis of methyl 6-((2-oxo-5-phenyloxazol-3(2H)-yl)methyl)nicotinate [ka]

[0370] To a solution of methyl 6-(((tert-butoxycarbonyl)(phenylethynyl)amino)methyl)nicotinate (0.050 g, 0.136 mmol) synthesized in Step 2 in dichloromethane (0.5 mL) at room temperature, silver bis(trifluoromethanesulfonyl)imide (0.003 g, 0.007 mmol) was added and stirred at the same temperature for 1 hour. Saturated aqueous ammonium chloride solution 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 and then dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; ethyl acetate / hexane = 0% to 30%) and concentrated to give the title compound (0.030 g, 70.8%, yellow solid).

[0371] [Step 4] Synthesis of 6-((2-oxo-5-phenyloxazol-3(2H)-yl)methyl)nicotinohydrazide [ka]

[0372] A solution of methyl 6-((2-oxo-5-phenyloxazol-3(2H)-yl)methyl)nicotinate (0.016 g, 0.052 mmol) synthesized in Step 3 and hydrazine monohydrate (0.050 mL, 1.031 mmol) in ethanol (1 mL) at 80 °C was stirred at the same temperature for 18 hours, and then the temperature was lowered to room temperature to complete the reaction. The solvent was removed from the reaction mixture under reduced pressure, and the resulting product was used without further purification (0.016 g, 100.0%, white solid).

[0373] [Step 5] Synthesis of Compound 142 [ka]

[0374] To a solution of 6-((2-oxo-5-phenyloxazol-3(2H)-yl)methyl)nicotinohydrazide (0.015 g, 0.048 mmol) synthesized in Step 4 and triethylamine (0.040 mL, 0.290 mmol) in tetrahydrofuran (0.7 mL) at room temperature, 2,2-difluoroacetic anhydride (0.024 mL, 0.193 mmol) was added and stirred at 80 °C for 6 h. The temperature was then lowered to room temperature to complete the reaction. Saturated aqueous sodium bicarbonate was poured into the reaction mixture, which was then extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride and then dehydrated with anhydrous sodium sulfate. The mixture was then filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; hexane / ethyl acetate = 100% to 50%) and concentrated to give the title compound (0.008 g, 44.7%, white solid).

[0375] 1H NMR (400 MHz, CD3OD)δ 9.28(s, 1H), 8.53(dd, J=7.8, 2.2 Hz, 1H), 7.67(d, J=8.4 Hz, 1H), 7.56(d, J=7.6 Hz, 2H), 7.44-7.40(m, 3H), 7.33(t, J=7.4 Hz, 1H), 7.26(t, J=51.4 Hz, 1H), 7.26(t, J=51.4 Hz, 1H), 5.09(s, 2H); LRMS(ES)m / z 371.2(M + +1).

[0376] Following substantially the same procedures as in Example 142, the compounds in Table 23 below were synthesized.

[0377] [Table 40]

[0378] 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 [ka]

[0379] 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) in N,N-dimethylformamide (1 mL) at room temperature, potassium carbonate (0.060 g, 0.431 mmol) and potassium iodide (0.010 g, 0.057 mmol) were added and the mixture was stirred at 80 °C for 18 hours. The temperature was then lowered to room temperature to terminate the reaction. Water was poured into the reaction mixture, which was then extracted with ethyl acetate. The organic layer was washed with saturated aqueous sodium chloride and dehydrated with anhydrous sodium sulfate, then filtered and concentrated under reduced pressure. The concentrate was purified by column chromatography (SiO2, 4 g cartridge; dichloromethane / methanol = 100% to 80%) and concentrated to give the title compound (0.012 g, 10.9%, white solid).

[0380] 1 H NMR(400 MHz, CDCl3)δ 8.18(d, J=8.4 Hz, 2H), 8.15(dd, J=4.2, 1.8 Hz, 1H), 7.71(d, J=8.0 Hz, 2H), 7.62 ~ 7.57(m, 2H), 7.51 ~ 7.37(m, 3H), 6.95(t, J=51.8 Hz, 1H), 6.79(s, 1H), 5.66(s, 2H), 3.51(s, 3H); LRMS(ES)m / z 384.2(M + +1).

[0381] Protocols for measuring and analyzing the activity of the compounds of the present invention <Experimental Example 1> Confirmation of HDAC enzyme activity inhibition (in vitro) Experiments were carried out to confirm the selectivity of the compound represented by formula I of the present invention for HDAC6 through HDAC1 and HDAC6 enzyme activity inhibition experiments.

[0382] HDAC enzyme activity was measured using the HDAC Fluorimetric Drug Discovery Kit (BML-AK511, 516) from Enzo Life Sciences. For the HDAC1 enzyme activity assay, human recombinant HDAC1 (BML-SE456) was used as the enzyme source, and Fluor de Lys®-SIRT1 (BNL-KI177) was used as the substrate. Five-fold diluted compounds were dispensed into a 96-well plate, and 0.3 μg of enzyme and 10 μM substrate were added per well. The reaction was allowed to proceed at 30°C for 60 minutes. Fluor de Lys® Developer II (BML-KI176) was then added, and the reaction was allowed to proceed for 30 minutes. The fluorescence values ​​(Ex 360, Em 460) were then measured using a multi-plate reader (Flexstation 3, Molecular Devices). For the HDAC6 enzyme, Calbiochem's human recombinant HDAC6 (382180) was used, following the same protocol as for the HDAC1 enzyme activity assay. The final results were calculated as the respective IC values ​​using GraphPad Prism 4.0. 50 The values ​​were calculated and the results are summarized in Table 24 below.

[0383] [Table 41] [Table 42] [Table 43]

[0384] As shown in Table 24, the results of the activity inhibition test against HDAC1 and HDAC6 confirmed that the 1,3,4-oxadiazole derivative compounds of the present invention, their stereoisomers, or pharmaceutically acceptable salts thereof exhibit excellent selective HDAC6 inhibitory activity of about 185 to about 3497 times.

Claims

1. A 1,3,4-oxadiazole derivative compound represented by the following formula I, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof: Chemical I 【Chemical 1】 In the formula I, R １ is -C １－４ haloalkyl; X １ ~X ４ are each independently CR Ｘ or N; R Ｘ is -H, -C １－４ Alkyl, —C １－４ haloalkyl, or -halo; Y is CR Ｙ or N; R Ｙ is -H or -C １－４ is alkyl; Z is NR Ｚ , O, or S; R Ｚ is -H or -C １－４ is alkyl; W is O or S; m is 0 or 1; Ring V is aryl, heteroaryl, or hydroheteroaryl, wherein one or more H in said aryl, heteroaryl, or hydroheteroaryl ring is —C １－４ Alkyl, —C １－４ Aminoalkyl, -C １－４ Hydroxyalkyl, —C １－４ Haloalkyl, -halo, -(CH ２ ) n-cycloalkyl, —(CH ２ ) n-heterocycloalkyl, or —(CH ２ )n-heteroaryl, in which case the -(CH ２ ) n-cycloalkyl, —(CH ２ ) n-heterocycloalkyl, or —(CH ２ ) One or more H in the n-heteroaryl ring is -C １－４ Alkyl, —C １－４ and optionally substituted with haloalkyl, -halo, cycloalkyl, or heterocycloalkyl (wherein one or more H in the cycloalkyl or heterocycloalkyl ring is replaced with -C １－４ optionally substituted with alkyl; and n is 0, 1, or 2.

2. R １ is -C １－４ haloalkyl; X １ is N; X ２ ~X ４ are each independently CR Ｘ and R Ｘ is —H or -halo; Y is CR Ｙ or N; R Ｙ is —H; Z is NR Ｚ , O, or S; R Ｚ is -C １－４ is alkyl; W is O or S; m is 0 or 1; Ring V is aryl, heteroaryl, or hydroheteroaryl, wherein one or more H in said aryl, heteroaryl, or hydroheteroaryl ring is —C １－４ Alkyl, —C １－４ Aminoalkyl, -halo, -(CH ２ ) n-cycloalkyl, —(CH ２ ) n-heterocycloalkyl, or —(CH ２ )n-heteroaryl, in which case the -(CH ２ ) n-cycloalkyl, —(CH ２ ) n-heterocycloalkyl, or —(CH ２ ) One or more H in the n-heteroaryl ring is -C １－４ and optionally substituted with alkyl, -halo, cycloalkyl, or heterocycloalkyl (wherein one or more H in the cycloalkyl or heterocycloalkyl ring is replaced with —C １－４ optionally substituted with alkyl; and n is 0 or 1; 2. The 1,3,4-oxadiazole derivative compound according to claim 1, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof.

3. R １ is -CF ２ H or -CF ３ is; 2. The 1,3,4-oxadiazole derivative compound according to claim 1, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof.

4. X １ is N; and X ２ ~X ４ are each independently CH or CF; 2. The 1,3,4-oxadiazole derivative compound according to claim 1, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof.

5. 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; 2. The 1,3,4-oxadiazole derivative compound according to claim 1, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof.

6. Ring V is phenyl, a 5- to 10-membered heteroaryl, or a 9- to 10-membered hydroheteroaryl, wherein one or more H in said phenyl, 5- to 10-membered heteroaryl, or 9- to 10-membered hydroheteroaryl ring is selected from the group consisting of -C １－４ Alkyl, —C １－４ Aminoalkyl, -halo, -(CH ２ ) n-cycloalkyl, —(CH ２ ) n-heterocycloalkyl, or —(CH ２ )n-heteroaryl, in which case the -(CH ２ ) n-cycloalkyl, —(CH ２ ) n-heterocycloalkyl, or —(CH ２ ) One or more H in the n-heteroaryl ring is -C １－４ and optionally substituted with alkyl, -halo, 4- to 6-membered cycloalkyl, or 4- to 6-membered heterocycloalkyl (wherein one or more H in said 4- to 6-membered cycloalkyl or 4- to 6-membered heterocycloalkyl ring is replaced with —C １－４ optionally substituted with alkyl; and n is 0 or 1; 2. The 1,3,4-oxadiazole derivative compound according to claim 1, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof.

7. The compound represented by formula I is a 1,3,4-oxadiazole derivative compound, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof according to claim 1, which is any one selected from the group consisting of the following compounds: 【Chemistry 2】 【Chemistry 3】 【Chemistry 4】 【Chemistry 5】 【Chemistry 6】 【Chemistry 7】 【Chemistry 8】 。

8. A pharmaceutical composition for preventing or treating a histone deacetylase 6-mediated disease, comprising as an active ingredient a compound represented by formula I according to any one of claims 1 to 7, a stereoisomer thereof, or a pharmaceutically acceptable salt thereof.

9. The histone acetyltransferase 6 mediated disease is an infectious disease; a neoplasm; an endocrine, nutritional and metabolic disease; a mental and behavioral disorder; a neurological disease; an eye and appendage disease; a cardiovascular disease; a respiratory disease; a gastrointestinal disease; a skin and subcutaneous tissue disease; a musculoskeletal and connective tissue disease; or a congenital malformation, deformity and chromosomal abnormality. The pharmaceutical composition for preventing or treating a histone deacetylase 6-mediated disease according to claim 8.

10. the endocrine, nutritional and metabolic disease is Wilson's disease, amyloidosis or diabetes; the mental and behavioral disorder is depression or Rett syndrome; the neurological disease is a central nervous system atrophy, a neurodegenerative disease, a movement disorder, a neuropathy, a motor neuron disease, or a central nervous system demyelinating disease; said ocular and adnexal disease is uveitis; said skin and subcutaneous tissue disease is psoriasis; the musculoskeletal and connective tissue disease is rheumatoid arthritis, osteoarthritis or systemic lupus erythematosus; the congenital malformation, deformity, or chromosomal abnormality is autosomal dominant polycystic kidney disease; the infectious disease is a prion disease, the neoplasm is a benign or malignant tumor; the cardiovascular disease is atrial fibrillation or stroke; the respiratory disease is asthma, and The gastrointestinal disease is alcoholic liver disease, inflammatory bowel disease, Crohn's disease or ulcerative colitis; The pharmaceutical composition for preventing or treating a histone deacetylase 6-mediated disease according to claim 9.

11. A method for preventing or treating a histone deacetylase 6-mediated disease, comprising administering a therapeutically effective amount of a compound represented by 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 of formula I according to any one of claims 1 to 7, a stereoisomer thereof or a pharmaceutically acceptable salt thereof for the manufacture of a medicament for the prevention or treatment of a histone deacetylase 6-mediated disease.

13. Use of a compound of formula I according to any one of claims 1 to 7, its stereoisomer, or a pharmaceutically acceptable salt thereof for the prevention or treatment of a histone deacetylase 6-mediated disease.

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