Isoxazole diphenyl ether compounds with BRD4 and BD2 inhibitory activity as well as preparation method and application of isoxazole diphenyl ether compounds

Abstract

The invention relates to the technical field of pharmacy, in particular to an isoxazole diphenyl ether compound with BRD4BD2 inhibitory activity and a preparation method and application of the isoxazole diphenyl ether compound. The invention provides an isoxazole diphenyl ether compound with BRD4BD2 inhibitory activity or a pharmaceutically acceptable salt thereof. The compound has a structural formula as shown in a general formula (I). The invention also provides application of the isoxazole diphenyl ether compound or the pharmaceutically acceptable salt thereof or the pharmaceutical composition containing the isoxazole diphenyl ether compound in preparation of drugs for preventing or treating cancers, inflammations and metabolic diseases related to BRD4BD2. Compared with the prior art, the benzisoxazole compound has the following technical effects: 1) benzisoxazole and a diphenyl ether skeleton are hybridized, and substituent groups are optimized, so that the combination effect of small molecules and target protein is improved, and the activity of the obtained optimal compound is higher than that of a compound in the prior art; and 2) the invention also provides a synthesis method of the BRD4BD2 inhibitor, and a target compound is efficiently prepared by designing a synthesis route.

Description

Technical Field

[0001] The present invention relates to the field of pharmaceutical technology, and in particular to an isoxazole diphenyl ether compound having BRD4 BD2 inhibitory activity, a preparation method and an application thereof. Background Art

[0002] Bromodomains (BRDs) are a class of conserved domains consisting of 60 to 110 amino acids, composed of four α-helices and several loop regions. They are epigenetic readers that play a key role in transcriptional activation by recognizing acetylated lysine residues on histones. Currently, the human proteome encodes 61 bromodomains, distributed across 46 different proteins, which are divided into eight families. The bromodomain and extra-terminal (BET) family is the most important, comprising four proteins: BRD2, BRD3, BRD4, and BRDT. Each protein contains two similar bromodomains (designated BD1 and BD2), resulting in a total of eight similar bromodomains in the BET family.

[0003] BET family bromodomain (BET-BRD) proteins bind to acetylated lysines on histones in chromatin promoter regions or super-enhancer regions through their bromodomains, then bind to positive transcription elongation factor b (p-TEFb), recruiting p-TEFb to chromatin. Furthermore, BET-BRD proteins can recruit mediators and transcription factors (such as the oncogene MYC and nuclear factor kappa B (NF-κB)) to form a super-elongation complex. P-TEFb promotes serine phosphorylation of the C-terminal domain of RNA polymerase II (RNApol II), ultimately driving RNA polymerase II-mediated transcription of multiple genes (Filippakopoulos P., Nat. Rev. Drug Discov. 2014, 13, 337-356; Hung KL, Nature 2021, 600, 731-736). A large number of studies have shown that the disorder of BET proteins is widely associated with the occurrence and development of cancer, inflammation, and metabolic diseases (Faivre E.J., Nature 2020, 578, 306-310; Aggarwal R., Clin. Cancer Res. 2022, 28, 3979-3989; Latif AL, Nat. Commun. 2021, 12, 241; Wang Z.-Q., Signal Transduct. Tar. 2023, 8, 420.).

[0004] Because BET-BRD acts as an epigenetic reader, it is involved in regulating the expression of multiple genes in the human body, including normal and abnormal gene expression. New evidence shows that simultaneous inhibition of BET-BRD BD1 and BD2 can lead to a wider range of phenotypes, which may affect the maintenance of normal transcriptional programs; selective inhibition of BD2 can specifically affect the expression of some pathogenic genes, with little effect on the maintenance of normal transcriptional programs, and the resulting phenotype is more specific (Faivre EJ, Nature 2020, 578, 306-310; Divakaran A., Med. Res. Rev. 2023, 43, 972-1018).

[0005] The first generation of BET-BRD inhibitors have inhibitory activity on the eight bromodomains of the BET family. Currently, a number of BET-BRD inhibitors have entered clinical trials for the treatment of various tumors (Shorstova T., Brit. J. Cancer 2021, 124, 1478-1490). However, clinical data show that clinical trials of most inhibitors are not very successful. The main problem is the generation of dose-limiting toxicities such as thrombocytopenia and gastrointestinal toxicity. At present, it is considered necessary to develop inhibitors that are selective for the BD1 or BD2 domains of the BET-BRD protein, which is expected to reduce dose-limiting toxicities. There are still few publicly reported BET-BRD BD2 inhibitors with excellent comprehensive performance. Apabetalone (RVX-208) is the first reported inhibitor that is partially selective for BRD-BD2, and the compound has entered Phase III clinical trials. Currently, RVX-208 is primarily used for coronary artery disease, type 2 diabetes, and acute pneumonia syndrome (Dhulkifle H., Acs Pharmacol. Transl. 2024, 7, 546-559); it has also been granted Breakthrough Therapy Designation by the FDA for use in combination with standard treatments (statins) as a secondary prevention therapy for adverse cardiovascular events caused by type 2 diabetes and acute coronary syndrome. However, the compound's activity and selectivity are not yet high enough (Picaud S., Proc. Natl. Acad. Sci. USA 2013, 110, 19754-19759; Faivre EJ, Nature 2020, 578, 306-310). ABBV-744 is a BET-BRD BD2 inhibitor developed by AbbVie and has entered Phase I clinical trials for myelofibrosis. ABBV-744 also has some disadvantages, such as the low clearance of the compound in mice and dogs; in addition, the compound is not effective at low micromolar concentrations (IC 50=3.1 μM) inhibits hERG potassium channels and has potential risks for cardiovascular disease (WO 2022116968 A1).

[0006] Therefore, there is still a need to develop more small molecule compounds with novel structures. New structures may exhibit new properties (activity, selectivity and drugability) and provide candidates for drug development. Summary of the Invention

[0007] In order to overcome the deficiencies of the prior art, the present invention aims to provide a class of isoxazole diphenyl ether compounds with BRD4 BD2 inhibitory activity, as well as a preparation method and application thereof.

[0008] The specific technical solutions of the present invention are as follows:

[0009] In a first aspect of the present invention, a class of isoxazole diphenyl ether compounds or pharmaceutically acceptable salts thereof having BRD4 BD2 inhibitory activity is provided, wherein the compound has a structural formula as shown in general formula (I):

[0010]

[0011] in,

[0012] R is selected from H or LR'; when R is selected from LR', L is connected to the amino group in the general formula (I);

[0013] L is selected from -SO2- or -CO-;

[0014] R′ is selected from Any one of a heterocyclic group, a C1-C6 alkyl group, and a C3-C6 cycloalkyl group; wherein R1-R5 are selected from H or halogen; and the heterocyclic group is selected from thienyl, pyrazolyl, or pyridyl.

[0015] The term "C1-C6 alkyl" refers to a saturated alkyl group of 1 to 6 carbon atoms, including straight-chain and branched-chain groups.

[0016] The term "C3-C6 cycloalkyl" refers to a saturated cycloalkyl group of 3 to 6 carbon atoms.

[0017] Preferably, R' is selected from any one of the following substituents: 2-chlorophenyl, 2-thienyl, 1-methyl-1H-4-pyrazolyl, 3-pyridyl, ethyl, n-propyl, isopropyl or cyclopropyl.

[0018] More preferably, R is selected from any one of the following substituents: hydrogen, cyclopropylsulfonyl, n-propylsulfonyl, 1-methyl-1H-pyrazole-4-sulfonyl, ethylsulfonyl, thiophene-2-sulfonyl, pyridine-3-sulfonyl, propionyl, 2-chlorobenzenesulfonyl, isopropylsulfonyl.

[0019] In a preferred embodiment of the present invention, the compound of general formula (I) is preferably any one of the following compounds:

[0020] 4-(2,4-Difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)aniline (SW-0).

[0021] N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)cyclopropanesulfonamide (SW1)

[0022] N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)propane-1-sulfonamide (SW-2)

[0023] N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)-1-methyl-1H-pyrazole-4-sulfonamide (SW-3)

[0024] N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)ethanesulfonamide (SW-4)

[0025] N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)thiophene-2-sulfonamide (SW-7)

[0026] N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)pyridine-3-sulfonamide (SW-8)

[0027] N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)propanamide (SW-9)

[0028] 2-Chloro-N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)benzenesulfonamide (SW-11)

[0029] N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)propane-2-sulfonamide (SW-12).

[0030] The specific structures of each compound are shown in Table 1:

[0031] Table 1 Structures of preferred compounds

[0032]

[0033]

[0034] More preferably,

[0035] The isoxazole diphenyl ether compound is any one of the following compounds:

[0036] N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)cyclopropanesulfonamide (SW-1). N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)propane-1-sulfonamide (SW-2). N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)ethanesulfonamide (SW-4). N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)propane-2-sulfonamide (SW-12).

[0037] In the present invention, pharmaceutically acceptable salts may include acid addition salts formed between the compound of formula (I) and the following acids: hydrobromic acid, hydrochloric acid, sulfuric acid, phosphoric acid, borate, methanesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, benzenesulfonic acid, citric acid, lactic acid, pyruvic acid, tartaric acid, acetic acid, maleic acid, succinic acid, mandelic acid, fumaric acid, salicylic acid, or phenylacetic acid. In addition, acid salts with inorganic bases, such as salts containing basic metal cations, alkaline earth metal cations, or ammonium cations, are also included.

[0038] In the second aspect of the present invention, a pharmaceutical composition is provided, comprising a compound as described in the first aspect or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable excipient. The compound or a pharmaceutically acceptable salt thereof is the key active ingredient of the pharmaceutical composition, which is used to treat a disease or improve symptoms. Pharmaceutically acceptable excipients are used to improve the physical properties, stability, solubility, bioavailability and other characteristics of the drug, and include but are not limited to fillers, disintegrants, binders, lubricants, stabilizers, flavoring agents, etc. The pharmaceutical composition can be prepared into a variety of dosage forms, such as tablets, capsules, injections, oral solutions, granules, etc., to meet the medication needs and administration routes of different patients.

[0039] In a third aspect of the present invention, there is provided the use of a compound of formula (I) or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition comprising the same, in the preparation of a medicament for inhibiting BRD4 BD2. Specifically, the present invention provides the use of an isoxazole diphenyl ether compound of formula (I) or a pharmaceutically acceptable salt thereof, or a pharmaceutical composition comprising the same, in the preparation of a medicament for preventing or treating cancer, inflammation, and metabolic diseases associated with BRD4BD2, wherein the cancer is leukemia, prostate cancer, or colon cancer, and the metabolic disease is diabetes or coronary artery disease.

[0040] In a fourth aspect of the present invention, a method for preparing the isoxazole diphenyl ether compound as described in the first aspect is provided.

[0041] The present invention adopts the following synthetic route to prepare the compound of general formula (I):

[0042]

[0043] The substituent R in the compound of general formula (I) is the same as defined in the first aspect.

[0044] The preparation method of the compound of general formula (I) specifically comprises the following steps:

[0045] 1) 1-(5-bromo-2-hydroxyphenyl)ethan-1-one, hydroxylamine hydrochloride, and sodium acetate are subjected to an oximation reaction to obtain compound 1-b, i.e., 1-(5-bromo-2-hydroxyphenyl)ethan-1-one oxime; the molar ratio of 1-(5-bromo-2-hydroxyphenyl)ethan-1-one, hydroxylamine hydrochloride, and sodium acetate is 1:1.5-2:1.5-2, the solvent is ethanol and water (volume ratio is 5:5-9:1), the reaction temperature is 77-85° C., and the reaction time is 1.5 to 4 hours;

[0046] 2) Compound 1-b and N,N-dimethylformamide dimethyl acetal (DMF-DMA) are subjected to a dehydration cyclization reaction to obtain compound 1-c, namely 5-bromo-3-methylbenzo[d]isoxazole; the molar ratio of 1-b to DMF-DMA is 1:4-5.2, the solvent is 1,4-dioxane, the reaction temperature is 100° C., and the reaction time is 8-30 min;

[0047] 3) 3-bromo-4-fluoronitrobenzene, 2,4-difluorophenol, and potassium carbonate are subjected to a substitution reaction to obtain compound 2-b, namely 2-bromo-1-(2,4-difluorophenoxy)-4-nitrobenzene; the molar ratio of 3-bromo-4-fluoronitrobenzene, 2,4-difluorophenol, and potassium carbonate is 1:1-1.2:1.5-3, the solvent is N,N-dimethylformamide, the reaction temperature is 70-90° C., and the reaction time is 2-5 hours;

[0048] 4) Compound 2-b, stannous chloride dihydrate, and concentrated hydrochloric acid were subjected to a reduction reaction to obtain compound 2-c, namely 3-bromo-4-(2,4-difluorophenoxy)aniline; the molar ratio of compound 2-b, stannous chloride dihydrate, and concentrated hydrochloric acid was 1:2-4:4-6, the solvent was ethanol, the reaction temperature was room temperature, and the reaction time was 12 h;

[0049] 5) Compound 2-c, pinacol diboronate, tris(dibenzylideneacetone)dipalladium (Pd2(dba)3), 1,3,5,7-tetramethyl-6-phenyl-2,4,8-trioxa-6-phosphoryladamantane (meCgPPh), and potassium acetate were subjected to borate esterification reaction to obtain compound 2-d, i.e., 4-(2,4-difluorophenoxy)-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline; the molar ratio of compound 2-c, pinacol diboronate, Pd2(dba)3, meCgPPh, and potassium acetate was 1:1.2-4:0.03-0.1:0.06-0.2:2-4, the solvent was 1,4-dioxane, the reaction system was vacuum, the reaction temperature was 80-110°C, and the reaction time was 12 h;

[0050] 6) Compound 2-d, 5-bromo-3-methylbenzisoxazole, [1,1-bis(diphenylphosphino)ferrocene] palladium dichloride (PdCl2(dppf)), and potassium phosphate were subjected to a Suzuki coupling reaction to obtain compound 2-e, i.e., 4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)aniline; the molar ratio of compound 2-d, 5-bromo-3-methylbenzisoxazole, PdCl2(dppf), and potassium phosphate was 1:1-1.2:0.05-0.2:4-8, the solvent was 1,4-dioxane and water (volume ratio 7-10:1), the reaction system was vacuum, the reaction temperature was 85-105°C, and the reaction time was 12 h;

[0051] 7) Compound 2-e is subjected to a sulfonylation or acylation reaction with different sulfonyl chlorides or acyl chlorides to obtain a final product; the molar ratio of compound 2-e to different sulfonyl chlorides or acyl chlorides is 1:1.1-3; the base used in the sulfonylation reaction is pyridine, and the volume-to-weight ratio of pyridine to 2-e is: 0.005-0.006 ml pyridine: 1 mg compound 2-e; the base used in the acylation reaction is triethylamine, and the molar ratio of compound 2-e to triethylamine is 1:1.5-3.5; the solvent is dichloromethane, the reaction temperature is room temperature to 40°C, and the reaction time is 2-12 hours.

[0052] Preferably,

[0053] In the step 1), the molar ratio of 1-(5-bromo-2-hydroxyphenyl)ethan-1-one, hydroxylamine hydrochloride, and sodium acetate is 1:1.6:1.6.

[0054] In the step 2), the molar ratio of compound 1-b to DMF-DMA is 1:4.6.

[0055] In the step 3), the molar ratio of 3-bromo-4-fluoronitrobenzene, 2,4-difluorophenol and potassium carbonate is 1:1:2.

[0056] In the step 4), the molar ratio of compound 2-b, stannous chloride dihydrate, and concentrated hydrochloric acid is 1:3.1:4.8.

[0057] In the step 5), the molar ratio of compound 2-c, pinacol diboronate, Pd2(dba)3, meCgPPh, and potassium acetate is 1:3:0.05:0.1:2.5.

[0058] In the step 6), the molar ratio of compound 2-d, 5-bromo-3-methylbenzisoxazole, PdCl2(dppf), and potassium phosphate is 1:1.1:0.08:6.5.

[0059] In the step 7), the sulfonyl chloride is selected from R1SO2Cl, the acyl chloride is selected from R1COCl; wherein R1 is selected from Any one of a heterocyclic group, a C1-C6 alkyl group, and a C3-C6 cycloalkyl group; wherein R1-R5 are selected from H or halogen; and the heterocyclic group is selected from thienyl, pyrazolyl, or pyridyl.

[0060] More preferably, in said step 7),

[0061] When cyclopropanesulfonyl chloride is used to carry out sulfonylation reaction with compound 2-e, the final product N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)cyclopropanesulfonamide (SW-1) is obtained;

[0062] When propylsulfonyl chloride is used to carry out sulfonylation reaction with compound 2-e, the final product N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)propane-1-sulfonamide (SW-2) is obtained;

[0063] When 1-methyl-1H-pyrazole-4-sulfonyl chloride is used to carry out sulfonylation reaction with compound 2-e, the final product N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)-1-methyl-1H-pyrazole-4-sulfonamide (SW-3) is obtained;

[0064] When ethylsulfonyl chloride is used to carry out sulfonylation reaction with compound 2-e, the final product N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)ethanesulfonamide (SW-4) is obtained;

[0065] When thiophene-2-sulfonyl chloride is used to carry out sulfonylation reaction with compound 2-e, the final product N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)thiophene-2-sulfonamide (SW-7) is obtained;

[0066] When pyridine-3-sulfonyl chloride is used to carry out sulfonylation reaction with compound 2-e, the final product N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)pyridine-3-sulfonamide (SW-8) is obtained;

[0067] When propionyl chloride is used to carry out acylation reaction with compound 2-e, the final product N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)propionamide (SW-9) is obtained;

[0068] When 2-chlorobenzenesulfonyl chloride is used to carry out sulfonylation reaction with compound 2-e, the final product 2-chloro-N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)benzenesulfonamide (SW-11) is obtained;

[0069] When isopropylsulfonyl chloride is used to carry out the sulfonylation reaction with compound 2-e, the final product N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)propane-2-sulfonamide (SW-12) is obtained.

[0070] The present invention has the following technical effects:

[0071] 1) The present invention improves the binding effect of small molecules with target proteins by hybridizing benzisoxazole and diphenyl ether skeletons and optimizing the substituents. The obtained optimal compound has higher activity than the prior art compounds.

[0072] 2) The present invention also provides a method for synthesizing the BRD4 BD2 inhibitor, and the target compound can be efficiently prepared by designing a synthetic route. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 This is a general formula diagram of the compound provided by the present invention.

[0074] Figure 2 The concentration inhibition curves of some representative compounds of the present invention on BRD4 BD2 are shown. DETAILED DESCRIPTION

[0075] The present invention is further described below with reference to examples. These examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0076] Example 1 Preparation of 4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)aniline (2-e, SW-0) Step 1 Preparation of 1-(5-bromo-2-hydroxyphenyl)-1-ethanone oxime (1-b)

[0077] 1-(5-Bromo-2-hydroxyphenyl)ethan-1-one (1-a) (20.0 g, 93.0 mmol) was dissolved in 60 mL of a mixed solvent of EtOH and water (V(EtOH):V(water)=7:3). Hydroxylamine hydrochloride (10.3 g, 148.8 mmol) and sodium acetate (12.2 g, 148.8 mmol) were added to the solution, and the reaction mixture was stirred at 80°C for 1.5 h. After completion of the reaction, the solvent was evaporated under reduced pressure, and water was added to the mixture with stirring until a large amount of solid precipitated. The solid was filtered, washed, and dried to obtain 21.2 g of a white solid with a yield of 99%. 1 HNMR (400MHz, CDCl3), δ11.15 (s, 1H), 7.52 (d, J = 2.4Hz, 1H), 7.34 (dd, J = 8.7, 2.4Hz, 1H), 7.30 (s, 1H), 6.86 (d, J = 8.7Hz, 1H), 2.34 (s, 3H).

[0078] Step 2 Preparation of 5-bromo-3-methylbenzo[d]isoxazole (1-c)

[0079] Compound 1-b (15 g, 65.2 mmol) was dissolved in 24 mL of 1,4-dioxane and DMF-DMA (35.7 g, 299.9 mmol) was added with vigorous stirring. The reaction mixture was heated to 100°C and stirred for 10 minutes. The reaction was monitored by TLC. After completion, two-thirds of the solvent was removed by evaporation under reduced pressure. Water was added to the residue, and the mixture was extracted with ethyl acetate (100 mL x 3). The combined organic layers were washed three times with water and once with saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (petroleum ether / ethyl acetate = 30:1, v / v) to obtain 8.9 g of a white solid in a 64% yield. 1 HNMR (400MHz, CDCl3) δ7.77 (d, J = 1.9 Hz, 1H), 7.62 (dd, J = 8.8, 1.7 Hz, 1H), 7.43 (d, J = 8.8 Hz, 1H), 2.56 (s, 3H).

[0080] Step 3 Preparation of 2-bromo-1-(2,4-difluorophenoxy)-4-nitrobenzene (2-b)

[0081] Dissolve 3-bromo-4-fluoronitrobenzene (3.38 g, 15.4 mmol) and 2,4-difluorophenol (2.0 g, 15.4 mmol) in 30 mL of DMF, add potassium carbonate (4.25 g, 30.7 mmol), and stir at 80°C for 4 h. Monitor the reaction by TLC. After completion, add 100 mL of water and extract with ethyl acetate (70 mL x 3). The combined organic layers are washed three times with water and once with saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to yield 4.92 g of an oil (97% yield). 1 HNMR (500MHz, DMSO-d6): δ8.57 (s, 1H), 8.19 (d, 1H, J = 9.1Hz), 7.62 (t, 1H, J = 10.6Hz), 7.52 (m, 1H), 7.24 (t, 1H, J = 8.0Hz), 6.99 (d, 1H, J = 9.1Hz).

[0082] Step 4 Preparation of 3-bromo-4-(2,4-difluorophenoxy)aniline (2-c)

[0083] Compound 2-b (4.92 g, 14.9 mmol) and stannous chloride dihydrate (10.43 g, 46.2 mmol) were dissolved in 40 mL of ethanol solution, 6 mL of hydrochloric acid was added, and the mixture was stirred at room temperature overnight. The reaction was monitored by TLC. After completion, 4 mol / L sodium hydroxide solution was added to adjust the pH to 7-8, 300 mL of water was added, and the mixture was extracted with ethyl acetate (100 mL×3). The combined organic layer was washed with water 3 times, washed with saturated brine once, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to obtain 4.37 g of an oily substance with a yield of 98% and a purity of 96.27%. R =4.083min. 1 HNMR (500MHz, DMSO-d6): δ7.37-7.41(m,1H),6.96-6.99(m,1H),6.88(d,1H,J=2.5Hz), 6.86 (d, 1H, J = 8.6Hz), 6.73-6.78 (m, 1H), 6.58 (dd, 1H, J = 8.6, 2.4Hz), 5.31 (s, 2H, NH2).

[0084] Step 5 Preparation of 4-(2,4-difluorophenoxy)-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline (2-d)

[0085] Compound 2-c (2.0 g, 6.66 mmol) and pinacol diboronate (5.08 g, 19.99 mmol) were dissolved in 50 mL of vacuum-degassed 1,4-dioxane. MeCgPPh (194.8 mg, 0.67 mmol), potassium acetate (1.64 g, 16.66 mmol), and Pd(dba) (305.14 mg, 0.33 mmol) were added sequentially. The reaction mixture was stirred at 100°C overnight under nitrogen. The reaction was monitored by TLC. After completion, 300 mL of water was added and the mixture was extracted with ethyl acetate (100 mL x 3). The combined organic layers were washed three times with water and once with saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (petroleum ether:ethyl acetate = 4:1, v / v) to obtain 0.75 g of an oily product in a 32% yield. This product was used directly in the next step.

[0086] Step 6 Preparation of 4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)aniline (2-e, SW-0)

[0087] Compound 2-d (0.75 g, 2.16 mmol) and 5-bromo-3-methylbenzisoxazole (0.50 g, 2.37 mmol) were dissolved in 28 mL of a vacuum-degassed mixture of 1,4-dioxane and water (1,4-dioxane:water = 7:1, v / v). Potassium phosphate (2.98 g, 14.03 mmol) and PdCl2(dppf) (126.36 mg, 0.17 mmol) were then added. The reaction mixture was stirred at 100°C overnight under nitrogen. The reaction was monitored by TLC. After completion, 100 mL of water was added and the mixture was extracted with ethyl acetate (70 mL x 3). The combined organic layers were washed three times with water and once with saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (petroleum ether:ethyl acetate = 4:1, v / v) to obtain 0.45 g of a white solid with a yield of 59% and a purity of 96.43%. R =3.570min; mp 132-133°C; 1 H NMR(400MHz,DMSO-d6)δ7.87(s,1H),7.79-7.52(m,2H),7.33-7.15(m,1H),6.97-6.75 (m,3H),6.74(d,J=2.3Hz,1H),6.63(dd,J=8.5,2.4Hz,1H),5.17(s,2H),2.53(s,3H); 13 C NMR(101MHz,DMSO-d6)δ161.21, 157.60,157.50,155.29,155.21,155.11(dd,J=241.4,10.1Hz,4'-ArC),152.96,152.84,150.50,150.38(dd, J＝248.5, 12.1 Hz, 2'-ArC ,146.22, 142.39, 142.35, 142.27, 142.23 (dd, J = 22.2, 4.0 Hz, 1'-ArC) ,142.26,133.26,132.46,131.16,122.04,121.56,121.10,118.66,118.59(d,J=7.1Hz,6'-ArC),115.99,114.41, 111.29, 111.26, 111.07, 111. ,109.14, 105.34, 105.12, 105.06, 104.84 (dd, J=28.3, 22.2Hz, 3'-ArC), 9.51.

[0088] Example 2 Preparation of N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)cyclopropanesulfonamide (SW-1)

[0089] Compound 2-e (50 mg, 0.14 mmol) was dissolved in 4 mL of dichloromethane, and then cyclopropanesulfonyl chloride (27.37 mg, 0.21 mmol) was added, and pyridine (0.25 mL) was added dropwise with stirring. The reaction mixture was stirred at 40 ° C overnight. TLC monitored the reaction. After completion, 50 mL of water was added and extracted with ethyl acetate (30 mL × 3). The combined organic layer was washed once with 2 mol / L hydrochloric acid (3 mL), washed 3 times with water, washed once with saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 4: 1, v / v) to obtain 58 mg of white solid, with a yield of 92% and a purity of 99.14%. t R =3.987min; mp167.3-168.2℃; 1 HNMR(400MHz,DMSO-d6)δ9.76(s,1H),7.95(s,1H),7.84-7.69(m,2H),7.45-7.32(m,2H),7.26(dd,J=8.8,2.7Hz,1H),7 .12(td,J=9.2,5.6Hz,1H),7.06-6.98(m,1H),6.96(d,J=8.8Hz,1H),2.71-2.63(m,1H),2.57(s,3H),1.04-0.86(m,4H). 13 C NMR (101MHz, CDCl3) δ162.34, 159.96, 159.85, 157.51, 157.41 (dd, J=​ ,155.29, ​ ​ ,152.05,139.96,139.93,139.85,139.81(dd,J=11.5,3.8Hz,1'-ArC),132.48,132.35,132.05,131.43,125.98,123.31,122.60, 121.91,121.89 ,121.83, 121.82,121.79 ​ 6'-ArC),117.97,111.52,111.48,111.29,111.25(dd,J=22.9,3.9Hz,5'-ArC),109.66,105.83, ​ ,29.87,10.12,5.73(2×C).

[0090] Example 3 N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)propane-1-sulfonamide (SW-2)

[0091] Prepared by referring to the method of Example 2, using compound 2-e and propylsulfonyl chloride as reactants. White solid; yield: 92%; t R =4.724min; mp165.9-167.1℃; 1 H NMR(400MHz,DMSO-d6)δ9.82(s,1H),7.95(s,1H),7.83-7.66(m,2H),7.38( ddd,J=11.5,8.9,3.0Hz,1H),7.34(d,J=2.7Hz,1H),7.23(dd,J=8.8,2.7Hz, 1H),7.12(td,J=9.2,5.6Hz,1H),7.06-6.98(m,1H),6.95(d,J=8.8Hz,1H),3 .10(t,J=7.6Hz,2H),2.56(s,3H),1.78-1.64(m,2H),0.96(t,J=7.4Hz,3H). 13 C NMR (101MHz,CDCl3)δ162.36, ​ ​ ,155.29, 155.06, 154.94,152.56,152.44(dd,J=251.5,12.2Hz,2'-ArC),151.77,139.95,139.91,139.83,139.79 ​,132.55,132.51,132.02,131.43,124.69,122.61,121.98, 121.92, 121.90,121.85,121.82,121.80(dd,J=9.6,2.0Hz,6'-ArC),118.14,111.52,111.48,111.29,111.26 ​ ​ ,109.68, ​ 3'-ArC),53.55,17.35,12.96,10.12.

[0092] Example 4 N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)-1-methyl-1H-pyrazole-4-sulfonamide (SW-3)

[0093] Prepared according to the method of Example 1, using compound 2-e and 1-methyl-1H-pyrazole-4-sulfonyl chloride as reactants. White solid; yield: 71%; t R =3.394min; mp101.4-102.4℃; 1 H NMR (400MHz, DMSO-d6) δ10.13(s,1H),8.25(s,1H),7.87(s,1H),7.78-7.65(m,3H),7.37(ddd,J=11.5,8.9,2.9Hz,1H),7.22(d,J=2.6 Hz,1H),7.13(dd,J=8.8,2.7Hz,1H),7.08(dd,J=9.2,5.6Hz,1H),7.05-6.97(m,1H),6.88(d,J=8.8Hz,1H),3.85(s,3H),2.57(s,3H). 13 C NMR(101MHz,DMSO-d6)δ161.43,159.00, ​ ,155.40, 154.10,153.82,151.63,151.50 (dd,J=249.0,12.8Hz,2'-ArC),149.89,140.01,139.97,139.89,139.86(dd,J=11.4,3.7Hz, ​ ,137.91,134.02,132.76,132.13,131.39,131.35,123.58,122.19,122.04, 121.83,121.73(d,J=10.1Hz,6'-ArC),121.44,120.96,118.33,112.01,111.78(d,J=22.9Hz,5'-ArC),109.46, 105.83,105.61,105.56,105.34 ​ ,39.03,9.56.

[0094] Example 5 N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)ethanesulfonamide (SW-4)

[0095] Prepared by referring to the method of Example 1, using compound 2-e and ethylsulfonyl chloride as reactants. White solid; yield: 85%; t R =3.968min; mp193.3-194.2℃; 1 H NMR (400MHz, DMSO-d6) δ9.83(s,1H),7.95(s,1H),7.80-7.69(m,2H),7.42-7.31(m,2H),7.24(dd,J=8.8,2.7Hz,1H),7.12( td,J=9.2,5.6Hz,1H),7.05-6.98(m,1H),6.95(d,J=8.8Hz,1H),3.13(q,J=7.3Hz,2H),2.56(s,3H),1.23(t,J=7.3Hz,3H). 13 C NMR(101MHz, CDCl3)δ162.38,159.98,159.88,157.53,157.43(dd,J=246.2,10.3Hz,4'-ArC),155.28,155.07,154.94,152.56,152 .44(dd,J=251.7,12.2Hz,2'-ArC),151.82,139.94,139.90,139.82,139.79(dd,J=11.6,3.7Hz,1'-ArC),132.57,132.45,131.99,1 31.42,124.76,122.62,122.08,121.93,121.91,121.84,121.83,121.75(dd,J=10.1,2.1Hz,6'-ArC),118.14,111.53,111.49,111. 30,111.26(dd,J=22.8,3.9Hz,5'-ArC),109.69,105.84,105.62,105.57,105.35(dd,J=26.9,21.9Hz,3'-ArC),46.17,10.13,8.34.

[0096] Example 6 N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)thiophene-2-sulfonamide (SW-7)

[0097] Prepared by referring to the method of Example 1, using compound 2-e and thiophene-2-sulfonyl chloride as reactants. White solid; yield: 64%; t R =3.968min; mp157.5-158.6℃; 1 H NMR (400MHz, DMSO-d6) δ10.43 (s, 1H), 7.95 (dd, J = 5.0, 1.2Hz, 1H), 7.83 (s, 1H), 7. 74(d,J=8.6Hz,1H),7.69(dd,J=8.7,1.6Hz,1H),7.56(dd,J=3.7,1.3Hz,1H),7.37( ddd,J=11.4,8.9,2.9Hz,1H),7.21(d,J=2.6Hz,1H),7.17(dd,J=4.9,3.8Hz,1H),7 .15-7.05(m,2H),7.03(dd,J=11.2,4.8Hz,1H),6.89(d,J=8.8Hz,1H),2.56(s,3H). 13 C NMR(101MHz,DMSO-d6)δ161.44,159.09,158.98,156.67,156.57(dd,J=242.9,10.6 ​ ,155.39, 154.15,154.03,151.68,151.55 ​ ,150.47,139.85,139.81,139.76,139.74,139.70(dd,J=11.4,3.7Hz,1'-ArC),133. 54,133.38,132.61,132.01,131.31,127.74(2×C),124.32,122.37,122.20,122.01, ​ 6'-ArC),118.22,112.06,112.03,111.83,111.80(dd,J=23.0,3.4Hz,5'-ArC),109.51,105.87, ​ ​ ,9.58.

[0098] Example 7 N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)pyridine-3-sulfonamide (SW-8)

[0099] Prepared according to the method of Example 1, using compound 2-e and pyridine-3-sulfonyl chloride as reactants. White solid; yield: 43%; t R =3.730min; mp102.4-103.4℃; 1 H NMR (400MHz, DMSO-d6) δ10.51(s,1H),8.89(d,J=2.0Hz,1H),8.86-8.78(m,1H),8.14(dt,J=8.2,2.1Hz,1H),7.83(s,1H),7.73(d,J=8.7Hz,1 H),7.70-7.63(m,2H),7.42-7.32(m,1H),7.19(d,J=2.6Hz,1H),7.16-7.05(m,2H),7.02(t,J=8.6Hz,1H),6.85(d,J=8.8Hz,1H),2.56(s,3H). 13 C NMR(101MHz,DMSO-d6)δ161.44,159.16,159.05,156.75,156.64(dd,J=242.9,10.8Hz,4'-ArC),155.39,154.21,154.08,153.61, ​ ,150.67,147.17, 139.68,139.64,139.57,139.53 (dd,J=11.5,3.7Hz,1'-ArC),135.65,134.87,132.89,131.88,131.38,13 1.31,124.63,124.44,122.46,122.20,122.16,122.14(6'-ArC),122.06, 118.15,112.09,112.05,111.82,111.82(dd,J=23.0,3.7Hz,5'-ArC),109 .49, 105.88, 105.66, 105.60, 105.38 (dd, J=27.5, 22.2Hz, 3'-ArC), 9.56.

[0100] Example 8 N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)propanamide (SW-9)

[0101] 3 mL of dichloromethane was added to a 10 mL sealed tube, followed by compound 2-e (50 mg, 0.14 mmol) and propionyl chloride (26.3 mg, 0.28 mmol), and triethylamine (30.36 mg, 0.30 mmol) was added dropwise with stirring. The reaction system was sealed and reacted at 40 ° C for 2 h. The reaction was monitored by TLC. After the reaction was completed, 50 mL of water was added and extracted with ethyl acetate (30 mL × 2). The combined organic layer was washed with water twice, washed with saturated brine once, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 4:1, v / v) to obtain 48 mg of white solid with a yield of 83%. t R =4.548min; mp187.1-188.2℃; 1 H NMR (400MHz, DMSO-d6) δ9.99(s,1H),7.94(s,1H),7.81(d,J=2.5Hz,1H),7.79-7.70(m,2H),7.57(dd,J=8.9,2.6Hz,1H),7.36(ddd,J=11.5,8. 9,2.9Hz,1H),7.06(td,J=9.1,5.7Hz,1H),7.03-6.96(m,1H),6.94(d,J=8.8Hz,1H),2.56(s,3H),2.33(q,J=7.5Hz,2H),1.09(t,J=7.5Hz,3H). 13 C NMR(101MHz,DMSO-d6)δ171.98,161.38, ​ ,155.38, 153.92, 153.80,151.43,151.32(dd,J=249.7,11.9Hz,2'-ArC),148.36,140.53,140.49,140.41,140.38(dd, ​ ,135.88,132.64,131.39,131.13,122.19,121.95,121.94, 121.23,121.14 (d,J=9.3Hz,6'-ArC),119.94,118.44,111.88,111.84,111.65,111.62(dd,J=23.1,3.7Hz, ​ ,109.36, ​ ​ ,29.48,9.67,9.57.

[0102] Example 9 2-Chloro-N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)benzenesulfonamide (SW-11)

[0103] Prepared by referring to the method of Example 1, using compound 2-e and 2-chlorobenzenesulfonyl chloride as reactants. White solid; yield: 58%; t R =2.687min; mp135.5-136.5℃; 1 H NMR (400MHz, DMSO-d6) δ10.66(s,1H),8.06(d,J=7.2Hz,1H),7.76(d,J=1.2 Hz,1H),7.73(d,J=8.7Hz,1H),7.70-7.61(m,3H),7.55(ddd,J=8.4,5.8,2. 9Hz,1H),7.35(ddd,J=11.3,8.8,2.9Hz,1H),7.20(d,J=2.7Hz,1H),7.09(d d,J=8.9,2.8Hz,1H),7.06-6.95(m,2H),6.84(d,J=8.9Hz,1H),2.56(s,3H). 13 C NMR (101MHz, CDCl3) δ162.31, 159.97, 159.86, 157.52, 157.42 (dd, J = 246.2, 10.3Hz, 4'-ArC), 155.21, 155.03, ​ ,152.22, 139.76,139.72,139.64,139.60 (dd,J=11.7,3.8Hz,1'-ArC),136.21,134.25,132.14,132.07,131.89,131.67,131.42,131.37,131.31,127.37,125.79,123.04,122.56, 121.97, ​ 6'-ArC),121.76,117.70,111.48,111.45,111.26,111.22(dd,J=22.9,3.9Hz,5'-A rC), 109.62, 105.79, 105.58, 105.53, 105.31 (dd, J=26.8, 21.9Hz, 3'-ArC), 10.10.

[0104] Example 10 N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)propane-2-sulfonamide (SW-12)

[0105] Prepared by referring to the method of Example 1, using compound 2-e and isopropylsulfonyl chloride as reactants. White solid; yield: 60%; t R=3.481min; mp87.5-88.5℃; 1 H NMR (400MHz, CDCl3) δ7.82(d,J=1.7Hz,1H),7.75(dd,J=8.7,1.7Hz,1H),7.55(d,J=8.7Hz,1H),7.37(d,J=2.7Hz,1H),7.2 0(dd,J=8.8,2.8Hz,1H),6.96-6.81(m,4H),6.81-6.72(m,1H),3.42-3.25(m,1H),2.60(s,3H),1.44(s,3H),1.42(s,3H). 13 C NMR (101MHz, CDCl3) δ162.34, 159.89, 159.78, 157.44, 157.34 (dd, J = 245.9, ​ ,155.30, ​ ​ ,151.43,140.06,140.02,139.94,139.90(dd,J=11.6,3.8Hz,1'-ArC),132.96,132.51,132.07,131.43,124.28,122.60,121.84, 121.76,121.74 ,121.69, 121.67, ​ ,118.24,111.47,111.43,111.24,111.20(dd,J=22.9,3.8Hz,5'-ArC),109.65,105.79,105.57, ​ ,52.76,16.62(2×C),10.11.

[0106] Purity and retention time determination of the compound of Example 11

[0107] Take an appropriate amount of compound and dissolve it in 1.5mL methanol, filter it through a 0.22μm microporous filter membrane and set aside. Use high performance liquid chromatography (Waters ARC-HPLC) to determine the purity and retention time of the compound. The chromatographic conditions are as follows: chromatographic column: Waters Symmetry C18 column (3.5um, 4.6×150mm), mobile phase: methanol: water (containing 5% methanol) = 80:20, flow rate: 0.8mL / min, column temperature: 30℃, detector: UV detector, detection wavelength: 254nm, injection volume: 10μL. The purity value is calculated using the area normalization method, and the retention time (t R ) was processed by the data workstation and read. The purity of all final products (SW-0 to SW-12) was greater than 95%, t RRecorded in the above embodiments.

[0108] Example 12 TR-FRET target activity test

[0109] Compound dilutions were prepared in DMSO in ECHO plates (Beckman). 15 μL biochemical reactions were performed in 384-well plates (OptiPlate-384, PerkinElmer). Each well reaction included 15 nL of compound, 5 μL of protein (N-terminally GST-tagged BRD4 BD2, amino acids 349-460) (final concentration 5 nM), 5 μL of peptide biotin (sequence: SGRG-K(Ac)-GG-K(Ac)-GLG-K(Ac)-GGA-K(Ac)-RHRKVGG-K (Biotin), synthesized by GL Company, China; final concentration 10 nM); and 5 μL of detection mixture (from EPIgeneous Binding Domain kit B, Revvity; the kit includes GST-Eu 3+ -Cryptate antibody and Streptavidin-XL665 reagent (final concentration of 1.25nM). The reaction mixture was shaken for 30 seconds and incubated at room temperature for 3 hours. The readings were made on an EnVision reader (PerkinElmer) with an excitation wavelength of 340nm and emission wavelengths of 615nm and 665nm. The blank control group (DMSO, detection buffer, polypeptide) and the high concentration control group (DMSO, protein, polypeptide) were used as references. The results were calculated by the fluorescence signals at 665nm and 615nm and expressed as HTRF ratio: HTRF ratio = F(665nm) / F(615nm). In the following formula, HTRF ratio is abbreviated as F. Inhibition rate = [1-(F inhibitor -F blankcontrol ) / F highcontrol -F blankcontrol ]×100. Inhibition curve and half-maximal inhibitory concentration (IC 50 ) values were calculated using GraphPad Prism 7 software.

[0110] Table 2 TSA assay for binding activity of compounds to BRD4(1) protein

[0111]

[0112]

[0113] Note: The control drug is RVX208 (for reference activity data, see the literature: Nature 578, 306-310 (2020)).

[0114] The results of the biological activity test show (Table 2) that the compounds SW-0 to SW-12 prepared in the present invention all have good BRD4BD2 protein binding effects (inhibitory effects). ​ The concentration-effect curves of representative compounds for inhibition of BRD4 BD2 are shown. Some compounds such as SW-1 (IC 50 =400.67nM), SW-2 (IC 50 =839.21nM), SW-4 (IC 50 =143.03nM), SW-12 (IC 50 =445.63 nM) showed better binding activity to BRD4 BD2 than the positive control compound RVX208.

[0115] The above are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention specification, or any direct or indirect application in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An isoxazole diphenyl ether compound or a pharmaceutically acceptable salt thereof having BRD4 BD2 inhibitory activity, characterized in that: The compound has the structural formula shown in general formula (I): in, R is selected from H or LR'; when R is selected from LR', L is connected to the amino group in the general formula (I); L is selected from -SO2- or -CO-; R′ is selected from Any one of a heterocyclic group, a C1-C6 alkyl group, and a C3-C6 cycloalkyl group; wherein R1-R5 are selected from H or halogen; and the heterocyclic group is selected from thienyl, pyrazolyl, or pyridyl.

2. The isoxazole diphenyl ether compound or a pharmaceutically acceptable salt thereof having BRD4 BD2 inhibitory activity according to claim 1, characterized in that: R' is selected from any one of the following substituents: 2-chlorophenyl, 2-thienyl, 1-methyl-1H-4-pyrazolyl, 3-pyridyl, ethyl, n-propyl, isopropyl or cyclopropyl.

3. The isoxazole diphenyl ether compound having BRD4 BD2 inhibitory activity or a pharmaceutically acceptable salt thereof according to claim 1, characterized in that: R is selected from any one of the following substituents: hydrogen, cyclopropylsulfonyl, n-propylsulfonyl, 1-methyl-1H-pyrazole-4-sulfonyl, ethylsulfonyl, thiophene-2-sulfonyl, pyridine-3-sulfonyl, propionyl, 2-chlorobenzenesulfonyl, isopropylsulfonyl.

4. The isoxazole diphenyl ether compound having BRD4 BD2 inhibitory activity or a pharmaceutically acceptable salt thereof according to claim 1, characterized in that: The compound of general formula (I) is preferably any one of the following compounds: 4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)aniline (SW-0); N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)cyclopropanesulfonamide (SW1); N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)propane-1-sulfonamide (SW-2); N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)-1-methyl-1H-pyrazole-4-sulfonamide (SW-3); N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)ethanesulfonamide (SW-4); N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)thiophene-2-sulfonamide (SW-7); N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)pyridine-3-sulfonamide (SW-8); N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)propionamide (SW-9); 2-Chloro-N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)benzenesulfonamide (SW-11); N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)propane-2-sulfonamide (SW-12).

5. A pharmaceutical composition comprising a compound according to any one of claims 1 to 4 or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable excipient.

6. Use of an isoxazole diphenyl ether compound or a pharmaceutically acceptable salt thereof or a pharmaceutical composition comprising the same as claimed in any one of claims 1 to 5 in the preparation of a drug for preventing or treating cancer, inflammation and metabolic diseases associated with BRD4 BD2.

7. The use according to claim 6, characterized in that The cancer is leukemia, prostate cancer or colon cancer, and the metabolic disease is diabetes or coronary artery disease.

8. The method for preparing an isoxazole diphenyl ether compound according to any one of claims 1 to 4, wherein: The compound of general formula (I) is prepared using the following synthetic route: The substituent R in the compound of general formula (I) is as defined in any one of claims 1 to 4; The preparation method of the compound of general formula (I) specifically comprises the following steps: 1) 1-(5-bromo-2-hydroxyphenyl)ethan-1-one, hydroxylamine hydrochloride, and sodium acetate are subjected to an oximation reaction to obtain compound 1-b, i.e., 1-(5-bromo-2-hydroxyphenyl)ethan-1-one oxime; the molar ratio of 1-(5-bromo-2-hydroxyphenyl)ethan-1-one, hydroxylamine hydrochloride, and sodium acetate is 1:1.5-2:1.5-2, the solvent is ethanol and water (volume ratio is 5:5-9:1), the reaction temperature is 77-85° C., and the reaction time is 1.5 to 4 hours; 2) Compound 1-b and N,N-dimethylformamide dimethyl acetal (DMF-DMA) are subjected to a dehydration cyclization reaction to obtain compound 1-c, namely 5-bromo-3-methylbenzo[d]isoxazole; the molar ratio of 1-b to DMF-DMA is 1:4-5.2, the solvent is 1,4-dioxane, the reaction temperature is 100° C., and the reaction time is 8-30 min; 3) 3-bromo-4-fluoronitrobenzene, 2,4-difluorophenol, and potassium carbonate are subjected to a substitution reaction to obtain compound 2-b, namely 2-bromo-1-(2,4-difluorophenoxy)-4-nitrobenzene; the molar ratio of 3-bromo-4-fluoronitrobenzene, 2,4-difluorophenol, and potassium carbonate is 1:1-1.2:1.5-3, the solvent is N,N-dimethylformamide, the reaction temperature is 70-90° C., and the reaction time is 2-5 hours; 4) Compound 2-b, stannous chloride dihydrate, and concentrated hydrochloric acid were subjected to a reduction reaction to obtain compound 2-c, namely 3-bromo-4-(2,4-difluorophenoxy)aniline; the molar ratio of compound 2-b, stannous chloride dihydrate, and concentrated hydrochloric acid was 1:2-4:4-6, the solvent was ethanol, the reaction temperature was room temperature, and the reaction time was 12 h; 5) Compound 2-c, pinacol diboronate, tris(dibenzylideneacetone)dipalladium (Pd2(dba)3), 1,3,5,7-tetramethyl-6-phenyl-2,4,8-trioxa-6-phosphoryladamantane (meCgPPh), and potassium acetate were subjected to borate esterification reaction to obtain compound 2-d, i.e., 4-(2,4-difluorophenoxy)-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline; the molar ratio of compound 2-c, pinacol diboronate, Pd2(dba)3, meCgPPh, and potassium acetate was 1:1.2-4:0.03-0.1:0.06-0.2:2-4, the solvent was 1,4-dioxane, the reaction system was vacuum, the reaction temperature was 80-110°C, and the reaction time was 12 h; 6) Compound 2-d, 5-bromo-3-methylbenzisoxazole, [1,1-bis(diphenylphosphino)ferrocene] palladium dichloride (PdCl2(dppf)), and potassium phosphate were subjected to a Suzuki coupling reaction to obtain compound 2-e, i.e., 4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)aniline; the molar ratio of compound 2-d, 5-bromo-3-methylbenzisoxazole, PdCl2(dppf), and potassium phosphate was 1:1-1.2:0.05-0.2:4-8, the solvent was 1,4-dioxane and water (volume ratio 7-10:1), the reaction system was vacuum, the reaction temperature was 85-105°C, and the reaction time was 12 h; 7) Compound 2-e is subjected to a sulfonylation or acylation reaction with different sulfonyl chlorides or acyl chlorides to obtain a final product; the molar ratio of compound 2-e to different sulfonyl chlorides or acyl chlorides is 1:1.1-3; the base used in the sulfonylation reaction is pyridine, and the volume-to-weight ratio of pyridine to 2-e is: 0.005-0.006 ml pyridine: 1 mg compound 2-e; the base used in the acylation reaction is triethylamine, and the molar ratio of compound 2-e to triethylamine is 1:1.5-3.5; the solvent is dichloromethane, the reaction temperature is room temperature to 40°C, and the reaction time is 2-12 hours.

9. The method for preparing an isoxazole diphenyl ether compound according to claim 5, wherein: In the step 1), the molar ratio of 1-(5-bromo-2-hydroxyphenyl)ethan-1-one, hydroxylamine hydrochloride, and sodium acetate is 1:1.6:1.6; In the step 2), the molar ratio of compound 1-b to DMF-DMA is 1:4.6; In the step 3), the molar ratio of 3-bromo-4-fluoronitrobenzene, 2,4-difluorophenol, and potassium carbonate is 1:1:2; In the step 4), the molar ratio of compound 2-b, stannous chloride dihydrate, and concentrated hydrochloric acid is 1:3.1:4.8; In the step 5), the molar ratio of compound 2-c, pinacol diboronate, Pd2(dba)3, meCgPPh, and potassium acetate is 1:3:0.05:0.1:2.5; In the step 6), the molar ratio of compound 2-d, 5-bromo-3-methylbenzisoxazole, PdCl2(dppf), and potassium phosphate is 1:1.1:0.08:6.5; In the step 7), the sulfonyl chloride is selected from R1SO2Cl, the acyl chloride is selected from R1COCl; wherein R1 is selected from Any one of a heterocyclic group, a C1-C6 alkyl group, and a C3-C6 cycloalkyl group; wherein R1-R5 are selected from H or halogen; and the heterocyclic group is selected from thienyl, pyrazolyl, or pyridyl.

10. The method for preparing an isoxazole diphenyl ether compound according to claim 7, wherein: In the step 7), When cyclopropanesulfonyl chloride is used to carry out sulfonylation reaction with compound 2-e, the final product N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)cyclopropanesulfonamide (SW-1) is obtained; When propylsulfonyl chloride is used to carry out sulfonylation reaction with compound 2-e, the final product N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)propane-1-sulfonamide (SW-2) is obtained; When 1-methyl-1H-pyrazole-4-sulfonyl chloride is used to carry out sulfonylation reaction with compound 2-e, the final product N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)-1-methyl-1H-pyrazole-4-sulfonamide (SW-3) is obtained; When ethylsulfonyl chloride is used to carry out sulfonylation reaction with compound 2-e, the final product N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)ethanesulfonamide (SW-4) is obtained; When thiophene-2-sulfonyl chloride is used to carry out sulfonylation reaction with compound 2-e, the final product N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)thiophene-2-sulfonamide (SW-7) is obtained; When pyridine-3-sulfonyl chloride is used to carry out sulfonylation reaction with compound 2-e, the final product N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)pyridine-3-sulfonamide (SW-8) is obtained; When propionyl chloride is used to carry out acylation reaction with compound 2-e, the final product N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)propionamide (SW-9) is obtained; When 2-chlorobenzenesulfonyl chloride is used to carry out sulfonylation reaction with compound 2-e, the final product 2-chloro-N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)benzenesulfonamide (SW-11) is obtained; When isopropylsulfonyl chloride is used to carry out the sulfonylation reaction with compound 2-e, the final product N-(4-(2,4-difluorophenoxy)-3-(3-methylbenzo[d]isoxazol-5-yl)phenyl)propane-2-sulfonamide (SW-12) is obtained.

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