NOVEL FXR AGONIST HAVING PYRAZINE STRUCTURE, AND PREPARATION METHOD AND USE

Abstract

The present invention relates to a novel FXR agonist having a pyrazine structure, a preparation method therefor and the use thereof, and in particular relates to a compound as represented by the following general formula (I), or a hydrate, a solvate or a pharmaceutically acceptable salt thereof or a resolved single isomer thereof, which has the effect of treating non-alcoholic fatty liver disease.

##STR00001##

Claims

1. A compound having the structure of Formula (I): ##STR00076## wherein R.sub.1 is halogen, COOH, ##STR00077## R.sub.2 is C.sub.1-C.sub.6 alkyl, cyclic hydrocarbyl, aryl, substituted alkyl, or substituted aryl; R.sub.3 is H, C.sub.1-C.sub.3 alkyl, cyclic hydrocarbyl, or substituted alkyl; and, X is C or N, or a hydrate, a solvate, a pharmaceutically acceptable salt, or a resolved single isomer thereof.

2. The compound according to claim 1, wherein R.sub.1 is Br; R.sub.2 is C.sub.1-C.sub.3 alkyl or cyclic hydrocarbyl; R.sub.3 is CH.sub.3.

3. The compound according to claim 1, wherein R.sub.2 is ##STR00078##

4. The compound according to claim 1, wherein said compound is ##STR00079## ##STR00080## ##STR00081## or a pharmaceutically acceptable salt thereof.

5. A pharmaceutical composition comprising a compound or a pharmaceutically acceptable salt thereof according to claim 1 as an active ingredient.

6. The pharmaceutical composition according to claim 5, further comprising a pharmaceutically acceptable carrier.

7. A method for preparing a compound according to claim 1, comprising Scheme 1: ##STR00082## ##STR00083##

8. A method for treating non-alcoholic fatty liver disease comprising administering to a subject in need thereof a compound according to claim 1.

9. The method according to claim 8, wherein the non-alcoholic fatty liver disease is non-alcoholic steatohepatitis.

10. A method for treating non-alcoholic fatty liver disease comprising administering to a subject in need thereof the pharmaceutical composition according to claim 5.

11. The method according to claim 10, wherein the non-alcoholic fatty liver disease is non-alcoholic steatohepatitis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0116] FIG. 1 is the .sup.1H-NMR spectrogram of compound TM-1 of the present invention;

[0117] FIG. 2 is the mass spectrogram of compound TM-1 of the present invention;

[0118] FIG. 3 is the .sup.1H-NMR spectrogram of compound TM-2 of the present invention;

[0119] FIG. 4 is the mass spectrogram of compound TM-2 of the present invention;

[0120] FIG. 5 is the .sup.1H-NMR spectrogram of compound TM-3 of the present invention;

[0121] FIG. 6 is the 1.sup.3C-NMR spectrogram of compound TM-3 of the present invention;

[0122] FIG. 7 is the mass spectrogram of compound TM-3 of the present invention;

[0123] FIG. 8 is the .sup.1H-NMR spectrogram of compound TM-4 of the present invention;

[0124] FIG. 9 is the mass spectrogram of compound TM-4 of the present invention;

[0125] FIG. 10 is the .sup.1H-NMR spectrogram of compound TM-5 of the present invention;

[0126] FIG. 11 is the mass spectrogram of compound TM-5 of the present invention;

[0127] FIG. 12 is the .sup.1H-NMR spectrogram of compound TM-6 of the present invention;

[0128] FIG. 13 is the 1.sup.3C-NMR spectrogram of compound TM-6 of the present invention;

[0129] FIG. 14 is the mass spectrogram of compound TM-6 of the present invention;

[0130] FIG. 15 is the .sup.1H-NMR spectrogram of compound TM-7 of the present invention;

[0131] FIG. 16 is the mass spectrogram of compound TM-7 of the present invention;

[0132] FIG. 17 is the .sup.1H-NMR spectrogram of compound TM-8 of the present invention;

[0133] FIG. 18 is the 1.sup.3C-NMR spectrogram of compound TM-8 of the present invention;

[0134] FIG. 19 is the mass spectrogram of compound TM-8 of the present invention;

[0135] FIG. 20 is the .sup.1H-NMR spectrogram of compound TM-9 of the present invention;

[0136] FIG. 21 is the 1.sup.3C-NMR spectrogram of compound TM-9 of the present invention;

[0137] FIG. 22 is the mass spectrogram of compound TM-9 of the present invention;

[0138] FIG. 23 is the .sup.1H-NMR spectrogram of compound TM-10 of the present invention;

[0139] FIG. 24 is the 1.sup.3C-NMR spectrogram of compound TM-10 of the present invention;

[0140] FIG. 25 is the mass spectrogram of compound TM-10 of the present invention.

DETAILED DESCRIPTION

[0141] The present invention is explained in detail below in conjunction with specific embodiments. Those skilled in the art can more fully understand the present patent. The specific embodiments are merely illustrative of the technical solutions of the present invention and do not limit the invention in any way. [0142] 1. The synthetic route for the (3-(2, 6-dichlorophenyl)-4-hydroxymethyl-5-cyclopropylisoxazole) intermediate is as follows:

##STR00035##

[0143] The synthesis method is as follows:

Synthesis of 2, 6-dichlorobenzaldehyde oxime

[0144] ##STR00036##

[0145] Hydroxylamine hydrochloride (11 g, 1 eq) and sodium hydroxide (6.3 g, 1.2 eq) were dissolved in water. A solution of 2, 6-dichlorobenzaldehyde (25 g, 0.14 mmol, 1.2 eq) in ethanol (200 mL) was added at room temperature. The mixture was stirred at 90 C. for 1 h. After cooling to room temperature, the ethanol was distilled off under reduced pressure. After the suction filtration, the filter cake is washed by water (2100 mL). After drying, a white solid (2, 6-dichlorobenzaldehyde oxime) 9.46 g was obtained in 84% yield.

1.2 Synthesis of 2, 6-dichloro-N-hydroxy-chlorobenzaldehyde oxime

[0146] ##STR00037##

[0147] A solution of N-chlorosuccinimide (16.08 g, 0.12 mol, 1 eq) in DMF (90 mL) was slowly added dropwise to a solution of 2, 6-dichlorobenzaldehyde oxime (22.8 g, 0.12 mol, 1 eq) in DMF (90 mL) at 40 C., stirred and monitored by TLC. After the reaction, the mixture was cooled to room temperature, poured into ice water (200 mL), extracted three times with methyl tert-butyl ether (3100 mL). The organic phase was combined, and then washed with water (3100 mL) and saturated salt solution (100 mL). After drying the ester layer with anhydrous sodium sulfate, suction filtration was performed, and the organic solvent was distilled off under reduced pressure to obtain the crude product as a yellow oil, which was separated and purified by silica gel column chromatography with gradient elution (PE:EA=5:1, v/v) to give a white solid (2,6-dichloro-N-hydroxy-chlorobenzaldehyde oxime) 26 g, yield 97%.

1.3 Synthesis of 3-(2, 6-dichlorophenyl)-5-cyclopropylisoxazole-4-methyl formate

[0148] ##STR00038##

[0149] 3-Cyclopropyl-methyl 3-oxopropionate (637.7 mg, 4.49 mmol, 1 eq) was added to a 100 mL reaction flask, which was sealed with a rubber stopper. Triethylamine (907.9 mg, 8.97 mmol, 2 eq) was added via a syringe to the reaction flask. The mixture was stirred vigorously at room temperature for 30 min. The reaction liquid was cooled to below 10 C. in an ice bath. A solution of 2, 6-dichloro-N-hydroxy-chlorobenzaldehyde oxime (1.0 g, 4.49 mmol, 1 eq) in ethanol was slowly added dropwise with stirring (monitoring internal temperature <24 C.). After slowly warming to room temperature and vigorously stirring overnight, the ethanol was distilled off under reduced pressure and extracted three times with ethyl acetate (3100 mL). The organic layer was washed with water (3100 mL), saturated salt solution (100 mL) and dried over anhydrous sodium sulfate to obtain crude oil. Silica gel column chromatography gradient elution separation and purification (PE:EA=40:1, v/v) was performed to give a white solid (methyl 3-(2, 6-dichlorophenyl)-5-cyclopropylisoxazole-4-methyl formate) 0.89 g, yield 55%.

1.4 Synthesis of 3-(2,6-dichlorophenyl)-4-hydroxymethyl-5-cyclopropylisoxazole

[0150] ##STR00039##

[0151] A solution of diisobutylaluminium hydride in toluene (4.0 mL, 6.0 mmol, 2.1 eq, 1.5M toluene solution) was slowly added dropwise to a solution of 3-(2, 6-dichlorophenyl)-5-cyclopropylisoxazole-4-methyl formate (0.89 g, 2.8 mmol, 1 eq) in anhydrous THF under the condition of nitrogen protection and ice bath. The mixture was allowed to warm to room temperature with vigorous stirring overnight. The reaction solution was re-cooled to 0 C. Methanol (2 mL) was slowly added dropwise and stirred for 10 min. The reaction solution was poured into 50 mL ice-water mixture, resulting in a gel-like suspension. The mixture was filtered by kieselguhr and extracted three times with ethyl acetate (3100 mL). The combined ester layer was washed with water (3100 mL) and saturated salt solution (100 mL), dried over anhydrous sodium sulfate and filtered to remove the solvent to give a white solid. Silica gel column chromatography gradient elution separation and purification (PE:EA=20:1, v/v) was performed to give a white solid (3-(2, 6-dichlorophenyl)-4-hydroxymethyl-5-cyclopropylisoxazole) 0.45 g in 56% yield.

2. Synthesis of 3-(2, 6-dichlorophenyl)-4-hydroxymethyl-5-isopropylisoxazole

2.1 Synthesis of 3-(2, 6-dichlorophenyl)-5-isopropylisoxazole-4-methyl formate

[0152] ##STR00040##

[0153] Methyl isobutyrylacetate (16.6 mL, 0.12 mol, 1 eq) was added into a 100 mL reaction flask, which was sealed with a rubber stopper. Triethylamine (33.25 mL, 0.24 mol, 2 eq) was added into the reaction flask via a syringe. The reaction flask was vigorously stirred at room temperature for 30 min. The reaction solution was cooled below 10 C. in an ice bath. A solution of 2, 6-dichloro-N-hydroxy-chlorobenzaldehyde oxime (26.6 g, 0.12 mol, 1 eq) in ethanol was slowly added dropwise with stirring (monitoring internal temperature <24 C.), slowly warmed to room temperature and vigorously stirred overnight. After removing ethanol by distillation under reduced pressure, ethyl acetate was added and the mixture was extracted three times (3100 mL). The organic layer was washed with water (3100 mL), saturated salt solution (100 mL) and dried over anhydrous sodium sulfate to obtain crude oil. Silica gel column chromatography gradient elution separation and purification (PE:EA=40:1, v/v) was performed to give a white solid (3-(2, 6-dichlorophenyl)-5-isopropylisoxazole-4-methyl formate) 21 g, yield 56%.

2.2 Synthesis of 3-(2, 6-dichlorophenyl)-4-hydroxymethyl-5-isopropylisoxazole

[0154] ##STR00041##

[0155] A solution of diisobutylaluminium hydride in toluene (92 mL, 0.14 mol, 2.1 eq, 1.5M toluene solution) was slowly added dropwise to a solution of 3-(2, 6-dichlorophenyl)-5-isopropylisoxazole-4-methyl formate (20 g, 0.06 mol, 1 eq) in anhydrous THF under the condition of nitrogen protection and ice bath. The mixture was allowed to warm to room temperature with vigorous stirring overnight. The reaction solution was re-cooled to 0 C. Methanol (20 mL) was slowly added dropwise and stirred for 10 min. The reaction solution was poured into 50 mL ice-water mixture, resulting in a gel-like suspension. The mixture was filtered by kieselguhr and extracted three times with ethyl acetate (3100 mL). The combined ester layer was washed with water (3100 mL) and saturated salt solution (100 mL), dried over anhydrous sodium sulfate and filtered to remove the solvent to give a white solid. Silica gel column chromatography gradient elution separation and purification (PE:EA=40:1, v/v) was performed to give a white solid (3-(2, 6-dichlorophenyl)-4-hydroxymethyl-5-isopropylisoxazole) 18 g in 94% yield.

3 Synthesis of 3-(2, 6-dichlorophenyl)-4-hydroxymethyl-5-phenylisoxazole

3.1 Synthesis of 3-(2, 6-dichlorophenyl)-5-phenylisoxazole-4-ethyl formate

[0156] ##STR00042##

[0157] Ethyl benzoylacetate (5.7 mL, 50 mmol, 1 eq) was added into a 100 mL reaction flask, which was sealed with a rubber stopper. Triethylamine (13.86 mL, 100 mmol, 2 eq) was added into the reaction flask via a syringe. The reaction flask was vigorously stirred at room temperature for 30 min. The reaction solution was cooled below 10 C. in an ice bath. A solution of 2, 6-dichloro-N-hydroxy-chlorobenzaldehyde oxime (10 g, 50 mmol, 1 eq) in ethanol was slowly added dropwise with stirring (monitor internal temperature <24 C.), slowly warmed to room temperature, and vigorously stirred overnight. After removing ethanol by distillation under reduced pressure, ethyl acetate was added and the mixture was extracted three times (3100 mL). The organic layer was washed with water (3100 mL), saturated salt solution (100 mL) and dried over anhydrous sodium sulfate to obtain crude oil. Silica gel column chromatography gradient elution separation and purification (PE:EA=40:1, v/v) was performed to give a white solid (3-(2, 6-dichlorophenyl)-5-phenylisoxazole-4-methyl formate) 11.7 g, yield 65%.

3.2 Synthesis of 3-(2, 6-dichlorophenyl)-4-hydroxymethyl-5-phenylisoxazole

[0158] ##STR00043##

[0159] A solution of diisobutylaluminium hydride in toluene (18 mL, 27 mmol, 2.1 eq, 1.5M toluene solution) was slowly added dropwise to a solution of 3-(2, 6-dichlorophenyl)-5-phenylisoxazole-4-methyl formate (4.72 g, 13 mmol, 1 eq) in anhydrous THF under the condition of nitrogen protection and ice bath. The mixture was allowed to warm to room temperature with vigorous stirring overnight. The reaction solution was re-cooled to 0 C. Methanol (20 mL) was slowly added dropwise and stirred for 10 min. The reaction solution was poured into 200 mL ice-water mixture, resulting in a gel-like suspension. The mixture was filtered by kieselguhr and extracted three times with ethyl acetate (3100 mL). The combined ester layer was washed with water (3100 mL) and saturated salt solution (100 mL), dried over anhydrous sodium sulfate and filtered to remove the solvent to give a white solid. Silica gel column chromatography gradient elution separation and purification (PE:EA=20:1, v/v) was performed to give a white solid (3-(2, 6-dichlorophenyl)-4-hydroxymethyl-5-phenylisoxazole) 9.1 g, 70% yield.

Embodiment 1: Synthetic Route of Compound TM-1

[0160] ##STR00044## ##STR00045##

3-(3-bromophenyl) cyclobutanone

[0161] ##STR00046##

[0162] To a solution of N, N-dimethylformamide (2.1 g, 24.6 mmol) in 1, 2-dichloroethane (40 mL) at 15 C., triflic anhydride (11.6 g, 41.0 mmol) was slowly added dropwise and the mixture was stirred at 15 C. for 30 min. 3-bromostyrene (3.0 g, 16.4 mmol) and 2, 4, 6-collidine (2.9 g, 24.6 mmol) were then added and the mixture was stirred at room temperature overnight. The reaction was quenched by adding water. The mixture was stirred at room temperature overnight. Dichloromethane was added to dilute and separate the organic phase, which was washed with water and saturated salt solution (200 ml), dried over anhydrous magnesium sulfate, filtered by suction, concentrated under reduced pressure, and separated and purified by silica gel column chromatography gradient elution (PE:EA=15:1, v/v) to obtain 3-(3-bromophenyl) cyclobutanone as a yellow solid, 1.3 g, yield 35%.

3-(3-oxocyclobutyl) methyl benzoate

[0163] ##STR00047##

[0164] Triethylamine (2.2 g, 21.3 mmol) was added to a mixed solvent of 3-(3-oxocyclobutyl) methyl benzoate (1.6 g, 7.1 mmol) and (1, l-bis (diphenylphosphino) ferrocene) dichloropalladium (520 mg, 0.7 mmol) in methanol (20 mL) and N,N-dimethylformamide (10 mL) at room temperature under a carbon monoxide balloon atmosphere. The mixture was heated to 55 C. for 18 hours, distilled off the solvent under reduced pressure and dissolved in ethyl acetate, washed with water. The organic layer was dried over anhydrous magnesium sulfate, suction filtered, concentrated under reduced pressure, and separated and purified by silica gel column chromatography gradient elution (PE:EA=3:1, v/v) to obtain 3-(3-oxocyclobutyl) methyl benzoate as a yellow oily solid 1.1 g, yield 75%.

4-(5-bromopyrazine-2-ylmethoxy)-5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazole

[0165] ##STR00048##

[0166] In a 100 ml round bottom flask, sodium hydride (4.9 g, 121.6 mmol) was placed, a small amount of petroleum ether was added, and the kerosene layer on the surface of the sodium hydride was washed twice. Tetrahydrofuran (30 ml) was added and the reaction flask was cooled in an ice bath at 0 C. 2, 5-dibromopyrazine (13.1 g, 55.3 mmol) was dissolved in tetrahydrofuran (10 ml) and added dropwise to the round bottom flask with stirring. After the reaction of 20 min, 1-a (5-cyclopropyl-3-(2,6-dichlorophenyl)-isoxazole-4-yl) methanol (15.7 g, 55.3 mmol) was dissolved in tetrahydrofuran (10 ml), and then slowly added dropwise to the reaction flask via a syringe. The temperature was warmed to room temperature and the reaction lasted for 12 h. After the reaction, the reaction solution was poured into 100 ml of ice-water mixture, and then extracted with ethyl acetate (3100 ml). The combined organic phase was washed with water and saturated salt solution and then dried by anhydrous MgSO.sub.4. Silica gel column chromatography gradient elution separation and purification (PE:EA=10:1, v/v) was performed to give white solid 6 (namely, 2-, (4-(5-bromopyrazine-2-ylmethoxy)-5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazole) 20.2 g, 83% yield.

3-(3-(5-((5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl) methyl benzoate

[0167] ##STR00049##

[0168] In a 100 ml three-necked flask under nitrogen protection, 6 (20.2 g, 45.8 mmol) was dissolved in tetrahydrofuran (80 ml) and the mixture was added into the reaction flask. Then the temperature was lowered to 78 C. N-butyl lithium (1.6M in hexane, 30.0 mL, 48.0 mmol) was slowly added dropwise. After stirring for 10 min, a solution of 3-(3-oxocyclobutyl) methyl benzoate 2 (9.0 g, 43.6 mmol) dissolved in tetrahydrofuran (20 ml) was slowly added dropwise. After reaction for 2 h at 78 C., the mixture was allowed to warm to room temperature overnight. After the reaction, the reaction was quenched with saturated ammonium chloride. The mixture was extracted with ethyl acetate. The organic phase was washed with saturated salt solution (200 ml), dried over anhydrous magnesium sulfate, and suction filtered. The organic solvent was distilled off under reduced pressure. Separated and purified by silica gel column chromatography gradient elution (PE:EA=15:1, v/v) was performed to obtain 3-(3-(5-((5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl) methyl benzoate as a yellow solid 5.6 g, 19% yield.

3-(3-(5-(5-cyclopropyl-3-(2, 6-dichlorophenyl)-4-ylmethoxy)-2-pyrazine)-1-hydroxycyclobutane) benzoic acid

[0169] ##STR00050##

[0170] 3-(3-(5-((5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl) methyl benzoate (5.6 g, 10.1 mmol) was dissolved in a mixed solvent of THF (10 mL) and methanol (10 mL). A solution of LiOH.Math.H.sub.2O (1.8 g, 42.6 mmol) in water (5 ml) was added at 35 C. The mixture was stirred overnight. The organic solvent was removed by distillation under reduced pressure. The pH was adjusted to 5 with 1N hydrochloric acid. The mixture was extracted three times by adding ethyl acetate, dried with anhydrous magnesium sulfate, with the solvent removed by distillation under reduced pressure, and separated and purified by high-pressure preparative liquid chromatography (acetonitrile:water=3:4, v/v) to obtain TM-1 3-(3-(5-(5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazole-4-ylmethoxy)-2-pyrazine)-1-hydroxycyclobutane) benzoic acid as a white solid 3.28 g, 57% yield.

[0171] As shown in FIG. 1, .sup.1H-NMR (400 MHz, DMSO-D6): 12.95 (s, 1H), 8.22-8.21 (m, 1H), 8.12-8.11 (m, 1H), 7.95-7.94 (m, 1H), 7.72 (d, J=2 Hz, 1H), 7.66-7.49 (m, 4H), 7.48-7.37 (m, 1H), 6.06 (s, 1H), 5.24 (s, 2H), 3.57-3.37 (m, 1H), 2.94-2.89 (m, 2H), 2.55-2.42 (m, 3H), 1.21 (d, J=24 Hz, 2H), 1.15 (d, J=16 Hz, 2H).

[0172] As shown in FIG. 2, SI-MS: m/z[M+H]+: Calcd. for C.sub.28H.sub.23Cl.sub.2N.sub.3O.sub.5: 551.1, Found: 552.2.

Embodiment 2: Synthetic Route of Compound TM-2

[0173] ##STR00051## ##STR00052##

Synthetic Steps

Synthesis of 3-(3-hydroxyazetidin-1-yl) methyl benzoate 3b

[0174] ##STR00053##

[0175] To a solution of methyl 3-iodobenzoate 3a (5.0 g, 19.1 mmol) in DMSO-D.sub.6 (70 mL) was added 3-azetidine-3-ol hydrochloride (2.5 g. 22.9 mmol), Cs.sub.2CO.sub.3 (15.5 g, 47.7 mmol), CuI (726 mg, 3.8 mmol) and L-proline (878 mg, 7.6 mmol). The mixture was then heated at 90 C. for 18 hours under argon atmosphere. The solution was diluted with ethyl acetate and water. Then the organic layer was washed with saline water three times, concentrated under reduced pressure, and separated and purified by silica gel column chromatography (DCM/MeOH=10/1, v/v) to give the product 3b as a white solid (2.7 g, 68%).

Synthesis of 3-(3-oxazacyclobutane-1-yl) methyl benzoate 3

[0176] ##STR00054##

[0177] Dimethyl sulfoxide (1.6 g, 20.3 mmol) was dissolved in dichloromethane (30 mL). Oxalyl chloride (1.3 g, 10.1 mmol) was added at 78 C. The mixture was stirred at 78 C. for 30 minutes. Then 3-(3-hydroxyazetidin-1-yl) methyl benzoate (1.4 g, 6.8 mmol) was dissolved in dichloromethane and slowly added dropwise to the reaction liquid at 78 C. with time controlled at 30 minutes, and then stirred at 78 C. for 30 minutes, followed by the addition of triethylamine (4.1 g, 40.5 mmol). The mixture reacted at 78 C. for 1 hour, and warmed to room temperature and reacted at room temperature for 2 hours. The reaction solution was diluted with water and extracted with ethyl acetate. The organic phase was washed with saturated salt solution, dried over anhydrous sodium sulfate, concentrated by suction filtration, and separated and purified by silica gel column chromatography (PE/EA=2/1) to give the product 3 as a white solid (0.9 g, 65%).

3-(3-(5-((5-cyclopropyl-3-(2, 6-dichlorophenyl)isoxazol-4-yl) methoxy)pyrazin-2-yl)-3-hydroxyazetidin-1-yl) methyl benzoate

[0178] ##STR00055##

[0179] In a 100 ml three-necked flask under nitrogen protection, 6 (1.9 g, 4.4 mmol) was dissolved in tetrahydrofuran (25 ml) and added into the reaction flask. The temperature was lowered to 78 C. N-butyl lithium (2.5M in hexane, 2.6 mL, 6.6 mmol) was slowly added dropwise. After stirring for 10 min, a solution of 3-(3-oxazacyclobutane-1-yl) methyl benzoate 3 (0.9 g, 4.4 mmol) dissolved in tetrahydrofuran (5 ml) was slowly added dropwise. After reaction for 2 h at 78 C., the mixture was allowed to warm to room temperature overnight. After the reaction, the reaction was quenched with saturated ammonium chloride. The mixture was extracted with ethyl acetate. The organic phase was washed with saturated salt solution (200 ml), dried over anhydrous magnesium sulfate, and suction filtered. The organic solvent was distilled off under reduced pressure. Separated and purified by silica gel column chromatography gradient elution (PE:EA=15:1, v/v) was performed to obtain a yellow solid 7 (namely 3-b) 3-(3-(5-((5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl) methyl benzoate 560 mg, 22% yield.

3-(3-(5-((5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxyazetidin-1-yl) benzoic acid

[0180] ##STR00056##

[0181] 3-(3-(5-((5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl) methyl benzoate (270 mg, 0.5 mmol) was dissolved in a mixed solvent of THF (3 ml) and methanol (3 ml). A solution of LiOH.Math.H.sub.2O (60 mg, 1.5 mmol) in water (3 ml) was added at 35 C. The mixture was stirred overnight. The organic solvent was removed by distillation under reduced pressure. The pH was adjusted to 5 with 1N hydrochloric acid. The mixture was extracted three times by adding ethyl acetate, dried with anhydrous magnesium sulfate, with the solvent removed by distillation under reduced pressure. Separated and purified by high-pressure preparative liquid chromatography (acetonitrile:water=3:4, v/v) was performed to obtain 3-(3-(5-((5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl benzoic acid) (namely TM-2) as a white solid 40 mg, yield 15%.

[0182] As shown in FIG. 3, .sup.1H-NMR (400 MHz, DMSO-D6): 8.22-8.21 (m, 1H), 8.08-8.08 (m, 1H), 7.59-7.51 (m, 4H), 7.27-7.25 (m, 2H), 7.00 (s, 1H), 6.67 (s, 1H), 5.24 (s, 2H), 4.21 (d, J=16 Hz, 2H), 3.98 (d, J=16 Hz, 2H), 2.51-2.50 (m, 1H), 1.22-1.18 (m, 2H), 1.15-1.12 (m, 2H).

[0183] As shown in FIG. 4, ESI-MS: m/z[M+H]+: Calcd. for C.sub.27H.sub.22Cl.sub.2N.sub.4O.sub.5: 552.1, Found: 553.1 (note, values are on right side of figure).

Embodiment 3: Synthetic Route of Compound TM-3

3-(3-bromophenyl)-1-(5-((5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazol-4-yl) methoxy) pyrazine-2-yl) cyclobutanol

[0184] ##STR00057##

[0185] In a 100 ml three-necked flask under nitrogen protection, 4-(5-bromopyrazine-2-ylmethoxy)-5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazole (1.14 g, 2.3 mmol) dissolved in anhydrous tetrahydrofuran (5 mL) was put into a reaction flask. Ethanol and liquid nitrogen were added into a 500 mL low-temperature Dewar flask to reduce the temperature to 78 C. N-butyllithium (1.7 ml, 2.7 mmol) was slowly added dropwise, and the mixture was stirred for 10 min. A solution of 3-(3-oxocyclobutanone) methyl benzoate (0.56 g, 2.5 mmol) dissolved in tetrahydrofuran (10 mL) was slowly added dropwise. The mixture was allowed to react for 2 h at 78 C. and then warm to room temperature to react overnight. After the reaction, the reaction liquid was slowly poured into an ice-water mixture, and extracted with ethyl acetate. The ester layer was washed with water (100 mL), dried over anhydrous magnesium sulfate, suction filtered, with the organic solvent distilled off under reduced pressure, and separated and purified by silica gel column chromatography gradient elution (PE:EA=10:1, v/v) to obtain 3-(3-bromophenyl)-(5-(5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazol-4-yl) methoxy) pyrazine-2-yl) cyclobutane-1-ol as a white solid, 567 mg, 42% yield.

[0186] As shown in FIG. 5, .sup.1H-NMR (400 MHz, CDCl3): 8.30 (1H, s), 8.06 (1H, d, J=4 Hz), 7.45 (1H, s), 7.42 (1H, d, J=1.6 Hz), 7.40 (1H, s), 7.36-7.32 (2H, m, J=16 Hz), 7.22-7.18 (2H, m, J=16 Hz), 5.23 (2H, s), 3.35-3.26 (1H, m), 2.99-2.93 (2H, m), 2.63-2.57 (2H, m), 2.36-2.29 (1H, m), 1.33-1.29 (2H, d, J=24 Hz), 1.21-1.16 (2H, d, J=16 Hz). As shown in FIG. 6, 1.sup.3C-NMR (100 MHz, DMSO-D6): 173.0, 159.6, 158.4, 150.9, 147.1, 130.0, 129.8, 129.3, 128.0, 127.9, 125.3, 122.6, 110.3, 71.0, 56.8, 44.5, 29.8, 8.5, 7.8.

[0187] As shown in FIG. 7, ESI-MS: m/z[M+2+H]+: Calcd. for C.sub.27H.sub.22BrCl.sub.2N.sub.3O.sub.3: 585.0222, Found: 588.0300.

Embodiment 4: Synthetic Route of Compound TM-4

1-(5-((5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazol-4-yl) methoxy) pyrazine-2-yl)-3-(3-(methylsulfonyl) phenyl) cyclobutanol

[0188] ##STR00058##

[0189] To a solution of 3-(3-bromophenyl)-1-(5-((5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazol-4-yl) methoxy) pyrazine-2-yl) cyclobutanol (500 mg, 0.85 mmol) in DMSO-D6 was added sodium methanesulfinate (130 mg, 1.28 mmol), CuI (50.2 mg, 0.26 mmol), L-proline (97.9 mg, 0.85 mmol) and diisopropylethylamine (DIPEA) (109.9 mg, 0.85 mmol). The mixture was stirred at 95 C. overnight, then diluted with water and extracted with EA. The organic phases were combined, washed with water and dried over Na.sub.2SO.sub.4. It was concentrated to dryness under reduced pressure and separated and purified by high pressure preparative liquid chromatography (acetonitrile:water=3:4, v/v) to obtain 1-(5-((5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazol-4-yl) methoxy) pyrazine-2-yl)-3-(3-(methylsulfonyl) phenyl) cyclobutanol as a white solid 324 mg, yield 65%.

[0190] As shown in FIG. 8, .sup.1H-NMR (400 MHz, CDCl3): 8.15 (s, 1H), 7.92 (s, 1H), 7.72-7.65 (m, 2H), 7.42-7.40 (m, 2H), 7.28-7.12 (m, 2H), 5.08 (s, 2H), 3.33-3.29 (m, 1H), 2.93-2.85 (m, 5H), 2.51-2.46 (m, 2H), 2.21-2.18 (m, 1H), 1.15 (d, J=16 Hz, 2H), 1.05 (d, J=16 Hz, 2H).

[0191] As shown in FIG. 9, ESI-MS: m/z[M+H]+: Calcd. for C.sub.28H.sub.25Cl.sub.2N.sub.3O.sub.5S: 585.1, Found: 586.3.

Embodiment 5: Synthetic Route of Compound TM-5

1-(5-((5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazol-4-yl) methoxy) pyrazine-2-yl)-3-(3-(phenylthio) phenyl) cyclobutanol

[0192] ##STR00059##

[0193] To a solution of 3-(3-bromophenyl)-1-(5-((5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazol-4-yl) methoxy) pyrazine-2-yl) cyclobutanol (1.0 g, 1.7 mmol) in toluene under argon protection was added DIEA (0.44 g, 3.41 mmol), thiobenzyl alcohol (0.21 g, 1.7 mmol), Pd.sub.2(dba).sub.3 (0.34 g, 0.37 mmol) and 4, 5-bisdiphenylphosphino-9, 9-dimethylxanthene (0.16 g, 0.27 mmol). The mixture was then stirred at 115 C. for 4 hours, and cooled to room temperature, diluted with water and extracted with EA. The organic phases were combined, washed with water and dried over Na.sub.2SO.sub.4. It was concentrated to dryness under reduced pressure and separated and purified by high pressure preparative liquid chromatography (acetonitrile:water=3:4, v/v) to obtain 1-(5-((5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazol-4-yl) methoxy) pyrazine-2-yl)-3-(3-(phenylthio) phenyl) cyclobutanol 367 mg as a white solid, yield 35%.

[0194] As shown in FIG. 10, .sup.1H-NMR (400 MHz, CDCl3): 8.23 (s, 1H), 8.01 (s, 1H), 7.46-7.54 (m, 3H), 7.23-7.33 (m, 8H), 7.14 (br d, J=7.6 Hz, 1H), 5.28 (s, 2H), 3.31-3.34 (m, 1H), 4.85 (H.sub.2O), 4.58 (HDO), 3.30 (CD.sub.3OD), 2.92-3.02 (m, 2H), 2.41-2.50 (m, 2H), 1.23 (s, 1H), 1.21 (br d, J=2.0 Hz, 2H), 1.19 (br d, J=2.0 Hz, 2H).

[0195] As shown in FIG. 11, ESI-MS: m/z[M+H]+: Calcd. for C.sub.33H.sub.27Cl.sub.2N.sub.3O.sub.3S: 615.1150, Found: 616.1421.

Embodiment 6: Synthesis of Compound TM-6

Synthesis of 4-(5-bromopyrazine-2-ylmethoxy)-5-isopropyl-3-(2, 6-dichlorophenyl) isoxazole

[0196] ##STR00060##

[0197] In a 100 mL round bottom flask, sodium hydride (60%, 0.83 g, 21 mmol) was placed, a small amount of petroleum ether was added, and the kerosene layer on the surface of the NaH was washed twice. 30 mL tetrahydrofuran was added and the reaction flask was cooled in a 0 C. ice bath. 2, 5-dibromopyrazine (833 mg, 3.5 mmol) was dissolved in 10 mL tetrahydrofuran and added dropwise to the round bottom flask with stirring. After the reaction for 20 min, 3-(2, 6-dichlorophenyl)-4-hydroxymethyl-5-isopropylisoxazole (1 g, 3.5 mmol) was dissolved in 10 mL of tetrahydrofuran, and the mixture was slowly dropped into the reaction flask by the needle tube. The reaction was allowed to warm to room temperature for 12 h. After the reaction, the reaction solution was poured into 100 mL of ice-water mixture, and then extracted with ethyl acetate (3100 mL). The combined organic phase was washed with water and saturated salt solution and dried by anhydrous MgSO.sub.4. Separation and purification by silica gel column chromatography gradient elution (PE:EA=10:1, v/v) was performed to give 4-(5-bromopyrazine-2-ylmethoxy)-5-isopropyl-3-(2, 6-dichlorophenyl) isoxazole as a white solid, 0.7 g, 53% yield.

Synthesis of 3-(3-(5-((3-(2, 6-dichlorophenyl)-5-isopropylisoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl) methyl benzoate

[0198] ##STR00061##

[0199] In a 100 ml three-necked flask under nitrogen protection, 4-(5-bromopyrazine-2-ylmethoxy)-5-isopropyl-3-(2, 6-dichlorophenyl) isoxazole (Ig, 2.3 mmol) dissolved in anhydrous tetrahydrofuran (20 mL) was put into a reaction flask. Ethanol and liquid nitrogen were added into a 500 mL low-temperature Dewar flask to reduce the temperature to 78 C. N-butyllithium (1.7 ml, 2.7 mmol) was slowly added dropwise, and the mixture was stirred for 10 min. A solution of 3-(3-oxocyclobutanone) methyl benzoate (0.51 g, 2.5 mmol) in tetrahydrofuran (10 mL) was slowly added dropwise. The mixture was allowed to warm to room temperature overnight after reaction for 2 h at 78 C. After the reaction, the reaction solution was slowly poured into an ice-water mixture and extracted with ethyl acetate, with the ester layer washed with water (100 mL), dried over anhydrous magnesium sulfate, suction filtered, with the organic solvent distilled off under reduced pressure, and separated and purified by silica gel column chromatography gradient elution (PE:EA=10:1, v/v) to obtain 3-(3-(5-((3-(2, 6-dichlorophenyl)-5-isopropylisoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl) methyl benzoate as a white solid 549 mg, 42% yield.

Synthesis of 3-(3-(5-(5-isopropyl-3-(2, isoxazole-4-ylmethoxy)-2-pyrazine)-1-hydroxycyclobutane) benzoic acid

[0200] ##STR00062##

[0201] 3-(3-(5-((3-(2, 6-dichlorophenyl)-5-isopropylisoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl) methyl benzoate (319 mg, 0.6 mmol, 1 eq) was dissolved in 20 mL THF and a solution of LiOH.Math.H.sub.2O (99 mg, 2.4 mmol, 4.2 eq) in water (5 mL) was added at 35 C. The mixture was stirred overnight. The organic solvent was removed by distillation under reduced pressure. The pH was adjusted to 5 with 1N hydrochloric acid. The mixture was extracted three times by adding ethyl acetate, dried with anhydrous magnesium sulfate, with the solvent removed by distillation under reduced pressure, and separated and purified by high-pressure preparative liquid chromatography. A Waters XBridge C18 column (150 nm*4.6 nm*3.5 um) is used, with a mobile phase of acetonitrile and water, a flow rate of 18 mL/min, fractions collected with a gradient of 45%-75%, and most of the acetonitrile removed by concentrating. The mixture was treated by lyophilization with a lyophilizer to give 126 mg of (3-(3-(5-(5-isopropyl-3-(2, 6-dichlorophenyl) isoxazole-4-ylmethoxy)-2-pyrazine)-1-hydroxycyclobutane) benzoic acid as a white powdery solid, yield 38%.

[0202] As shown in FIG. 12, .sup.1H-NMR (400 MHz, DMSO-D.sub.6): 12.97 (s, 1H), 8.20 (d, J=1.3 Hz, 1H), 8.09 (d, J=1.3 Hz, 1H), 7.95 (s, 1H), 7.79-7.77 (d, J=7.7 Hz, 1H), 7.63-7.61 (m, 2H), 7.55-7.53 (m, 2H), 7.44 (t, J=7.7 Hz, 1H), 6.09 (s, 1H), 5.19 (s, 2H), 3.61-3.54 (m, 1H), 3.42-3.33 (m, 1H), 2.90 (td, J=8.9, 2.5 Hz, 2H), 2.47-2.42 (m, 2H), 1.37 (d, J=7.0 Hz, 6H).

[0203] As shown in FIG. 13, 1.sup.3C-NMR (100 MHz, CDCl3): 176.8, 171.0, 159.3, 158.4, 150.9, 145.2, 131.2, 129.4, 128.7, 128.4, 128.2, 128.1, 128.0, 109.1, 71.1, 56.8, 44.5, 29.9, 27.0, 20.9, 1.0.

[0204] As shown in FIG. 14, ESI-MS: m/z[M+H]+: Calcd. for C.sub.28H.sub.25Cl.sub.2N.sub.3O.sub.5: 553.1171, Found: 554.1211.

Embodiment 7: Synthesis of Compound TM-7

Synthesis of 4-(5-bromopyrazine-2-ylmethoxy)-5-phenyl-3-(2, 6-dichlorophenyl) isoxazole

[0205] ##STR00063##

[0206] In a 100 mL round bottom flask, sodium hydride (60%, 0.83 g, 21 mmol) was placed, a small amount of petroleum ether was added, and the kerosene layer on the surface of the NaH was washed twice. 30 mL tetrahydrofuran was added and the reaction flask was cooled in a 0 C. ice bath. 2, 5-dibromopyrazine (833 mg, 3.5 mmol) was dissolved in 10 mL tetrahydrofuran and added dropwise to the round bottom flask with stirring. After the reaction for 20 min, 3-(2, 6-dichlorophenyl)-4-hydroxymethyl-5-phenylisoxazole (1.12 g, 3.5 mmol) was dissolved in 10 mL of tetrahydrofuran, and the mixture was slowly dropped into the reaction flask by the needle tube. The reaction was warmed to room temperature to react for 12 h. After the reaction, the reaction solution was poured into 100 mL of ice-water mixture, and then extracted with ethyl acetate (3100 mL). The combined organic phase was washed with water and saturated salt solution and dried by anhydrous MgSO4. Separation and purification by silica gel column chromatography gradient elution (PE:EA=10:1, v/v) was performed to give a white solid (4-(5-bromopyrazine-2-ylmethoxy)-5-phenyl-3-(2, 6-dichlorophenyl) isoxazole), 752 mg, 45% yield.

Synthesis of 3-(3-(5-((3-(2, 6-dichlorophenyl)-5-phenylisoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl) methyl benzoate

[0207] ##STR00064##

[0208] In a 100 mL three-necked flask under nitrogen protection, 4-(5-bromopyrazine-2-ylmethoxy)-5-phenyl-3-(2, 6-dichlorophenyl) isoxazole (1 g, 2.1 mmol) dissolved in anhydrous tetrahydrofuran (20 mL) was put into a reaction flask. Ethanol and liquid nitrogen were added into a 500 mL low temperature Dewar flask to reduce the temperature to 78 C. N-butyllithium solution (1.1N cyclohexane solution, 1.75 ml, 2.8 mmol) was added dropwise. After the mixture was stirred for 10 min, a solution of 3-(3-oxocyclobutanone) methyl benzoate (0.47 g, 2.3 mmol) dissolved in tetrahydrofuran (10 mL) was slowly added dropwise. The mixture was allowed to warm to room temperature to react overnight after reaction for 2 h at 78 C. After the reaction, the reaction solution was slowly poured into an ice-water mixture and extracted with ethyl acetate, with the ester layer washed with water (100 mL), dried over anhydrous magnesium sulfate, suction filtered, with the organic solvent distilled off under reduced pressure, and separated and purified by silica gel column chromatography gradient elution (PE:EA=10:1, v/v) to obtain 3-(3-(5-((3-(2, 6-dichlorophenyl)-5-phenylisoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl) methyl benzoate as a white solid 329 mg, yield 26%.

Synthesis of 3-(3-(5-(5-phenyl-3-(2, isoxazole-4-ylmethoxy)-2-pyrazine)-1-hydroxycyclobutane) benzoic acid

[0209] ##STR00065##

[0210] 3-(3-(5-((3-(2, 6-dichlorophenyl)-5-phenylisoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl) methyl benzoate (118 mg, 0.2 mmol, 1 eq) was dissolved in 20 mL THF and a solution of LiOH.Math.H.sub.2O (35 mg, 0.8 mmol, 4.2 eq) in water (5 mL) was added at 35 C. The mixture was stirred overnight. The organic solvent was removed by distillation under reduced pressure. The pH was adjusted to 5 with 1N hydrochloric acid. The mixture was extracted three times by adding ethyl acetate, dried with anhydrous magnesium sulfate, with the solvent removed by distillation under reduced pressure, and separated and purified by high-pressure preparative liquid chromatography. A Waters X Bridge C18 column (150 nm*4.6 nm*3.5 um) is used, with a mobile phase of acetonitrile and water, a flow rate of 18 mL/min, fractions collected with a gradient of 45%-75%, and most of the acetonitrile removed by concentrating. The mixture was treated by lyophilization with a lyophilizer to give 39 mg of (3-(3-(5-(5-phenyl-3-(2, 6-dichlorophenyl) isoxazole-4-ylmethoxy)-2-pyrazine)-1-hydroxycyclobutane) benzoic acid as a white powder solid, yield 33%.

[0211] As shown in FIG. 15, .sup.1H-NMR (400 MHz, DMSO-D6): 12.97 (s, 1H), 8.15 (d, J=1.3 Hz, 1H), 8.10 (d, J=1.3 Hz, 1H), 7.99-7.95 (m, J=16 Hz, 3H), 7.79-7.78 (d, J=4 Hz, 1H), 7.67-7.65 (m, J=8 Hz, 5H), 7.61-7.55 (m, J=8 Hz, 2H), 7.46-7.42 (m, 1H), 6.08 (s, 1H), 5.38 (s, 2H), 5.39-3.33 (m, 1H), 2.94-2.88 (m, 2H), 2.47-2.42 (m, 2H).

[0212] As shown in FIG. 16, ESI-MS: m/z[M+H]+: Calcd. for C.sub.31H.sub.23Cl.sub.2N.sub.3O.sub.5: 587.1015, Found: 588.1062.

Embodiment 8: Synthesis of Compound TM-8

[0213] ##STR00066##

3-methyl-5-methyl vinylbenzoate

[0214] ##STR00067##

[0215] In a 100 mL round bottom flask, methyl 3-bromobenzoate (1.12 g, 5 mmol), potassium vinyltrifluoroborate (820 mg, 6.12 mmol), PdCl.sub.2 (17.5 mg, 0.1 mmol), PPh.sub.3 (80 mg, 0.3 mmol) and Cs.sub.2CO.sub.3 (5 g, 15 mmol) were added, followed by THF (18 mL) and H.sub.2O (2 mL) under N.sub.2. The mixture was stirred at 80 C. for 22 h, and then cooled to room temperature, washed with water, dried over anhydrous magnesium sulfate and suction filtered, distillation under reduced pressure. Separation and purification by silica gel column chromatography gradient elution (PE:EA=60:1, v/v) was performed to give a pale pink oily liquid (3-methyl-5-methyl vinylbenzoate) 164 mg, yield 30%.

3-(2, 2-dichloro-3-oxocyclobutanone)-5-methyltoluate

[0216] ##STR00068##

[0217] 3-methyl-5-methyl vinylbenzoate (5.46 g, 31 mmol, 1 eq) was dissolved in diethyl ether (150 mL) under nitrogen protection. Zinc dust (6 g, 93 mmol, 3 eq) was added. After sonication for 30 min, a solution of trichloroacetyl chloride (8.7 mL, 77.5 mmol, 2.5 eq) in Et.sub.2O (50 mL) was added dropwise, with sonication continued for 30 min. The mixture was heated to 35 C. Sonication was continued for 2.5 h. After the reaction, it was cooled to room temperature and quenched by slowly dropwise addition of water (50 mL). The mixture was poured into water, stirred for 20 min, filtered, and rinsed with Et.sub.2O. The organic layer was washed with water (250 mL), saturated sodium bicarbonate (250 mL) and saturated sodium chloride (250 mL), dried over anhydrous magnesium sulfate, filtered, with the solvent distilled off under reduced pressure to give the crude product as a yellow oil. Separation and purification by silica gel column chromatography gradient elution (PE:EA=50:1, v/v) was performed to give 3-(2, 2-dichloro-3-oxocyclobutanone)-5-methyltoluate as a yellow oily liquid 3.56 g, yield 40%.

3-methyl-5-(3-oxocyclobutyl) methyl benzoate

[0218] ##STR00069##

[0219] 3-(2, 2-dichloro-3-oxocyclobutanone)-5-methyltoluate (2.79 g, 9.7 mmol, 1 eq) combined with zinc dust (2.54 g, 38.8 mmol, 4 eq) was dissolved in 60 mL acetic acid and the mixture was stirred at room temperature for 1 h. It was then refluxed for 3.5 h at 80 C. in an oil bath and cooled to room temperature after the reaction.

[0220] The solvent acetic acid was diluted with 100 mL of water and extracted with diethyl ether (340 mL). The combined organic phases were washed sequentially with saturated sodium carbonate solution (340 mL), water (100 mL), and saturated salt solution (100 mL). The drying was carried out with an amount of anhydrous MgSO.sub.4. Separation and purification by silica gel column chromatography gradient elution (PE:EA=50:1, v/v) was performed to give the compound (3-(3-oxocyclobutanone) methyl benzoate) 1.38 g, yield 65%.

Synthesis of 3-(3-(5-((5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl)-5-methyltoluate

[0221] ##STR00070##

[0222] In a 100 ml three-necked flask under nitrogen protection, 4-(5-bromopyrazine-2-ylmethoxy)-5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazole (1.02 g, 2.3 mmol) dissolved in anhydrous tetrahydrofuran (20 mL) was put into a reaction flask. Ethanol and liquid nitrogen were added into a 500 mL low-temperature Dewar flask to reduce the temperature to 78 C. N-butyllithium (1.7 ml, 2.7 mmol) was slowly added dropwise, and the mixture was stirred for 10 min. A solution of 3-methyl-5-(3-oxocyclobutyl) methyl benzoate (0.55 g, 2.5 mmol) dissolved in tetrahydrofuran (10 mL) was slowly added dropwise. The mixture was allowed to warm to room temperature to react overnight after reaction for 2 h at 78 C. After the reaction, the reaction solution was slowly poured into an ice-water mixture and extracted with ethyl acetate, with the ester layer washed with water (100 mL), dried over anhydrous magnesium sulfate, suction filtered, with the organic solvent distilled off under reduced pressure, and separated and purified by silica gel column chromatography gradient elution (PE:EA=10:1, v/v) to obtain 3-(3-(5-((5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl)-5-methyltoluate as a white solid, 47% yield.

3-(3-(5-((5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl)-5-methyl benzoic acid

[0223] ##STR00071##

[0224] 3-(3-(5-((3-(2, 6-dichlorophenyl)-5-isopropylisoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl)-5-methyl benzoate (116 mg, 0.2 mmol, 1 eq) was dissolved in 20 mL THF and a solution of LiOH.Math.H.sub.2O (35 mg, 0.8 mmol, 4.2 eq) in water (5 mL) was added at 35 C. The mixture was stirred overnight. The organic solvent was removed by distillation under reduced pressure. The pH was adjusted to 5 with 1N hydrochloric acid. The mixture was extracted three times by adding ethyl acetate, dried with anhydrous magnesium sulfate, with the solvent removed by distillation under reduced pressure, and separated and purified by high-pressure preparative liquid chromatography. A Waters X Bridge C18 column (150 nm*4.6 nm*3.5 um) is used, with a mobile phase of acetonitrile and water, a flow rate of 18 mL/min, fractions collected with a gradient of 45%-75%, and most of the acetonitrile removed by concentrating. The mixture was treated by lyophilization with a lyophilizer to give 3-(3-(5-((5-cyclopropyl-3-(2, 6-dichlorophenyl) isoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl)-5-methyl benzoic acid as a white powder solid, 37 mg, yield 33%.

[0225] As shown in FIG. 17, .sup.1H-NMR (400 MHz, DMSO-D6): 12.90 (1H, s), 8.21 (1H, d, J=1.2 Hz), 8.11 (1H, d, J=1.2 Hz), 7.74 (1H, s), 7.62-7.60 (3H, m), 7.56-7.52 (1H, m), 7.37 (1H, s), 6.06 (1H, s), 5.24 (2H, s), 3.38-3.29 (1H, m), 2.92-2.87 (2H, m), 2.59-2.53 (1H, m), 2.46-2.41 (2H, m), 2.35 (3H, s), 1.24-1.18 (2H, m), 1.16-1.14 (2H, m).

[0226] As shown in FIG. 18, 1.sup.3C-NMR (400 MHz, DMSO-D6): 6176.9, 168.9, 168.0, 159.3, 157.9, 153.5, 146.2, 135.1, 133.4, 133.0, 128.9, 127.6, 125.1, 109.9, 70.9, 56.3, 45.5, 29.8, 26.5, 21.3, 21.1.

[0227] As shown in FIG. 19, ESI-MS: m/z[M+H]+: Calcd. for C.sub.29H.sub.25Cl.sub.2N.sub.3O.sub.5: 565.1171, Found: 566.1234.

Embodiment 9: Synthesis of Compound TM-9

Synthesis of 3-(3-(5-((3-(2, 6-dichlorophenyl)-5-isopropylisoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl)-5-methyl toluate

[0228] ##STR00072##

[0229] In a 100 ml three-necked flask under nitrogen protection, 4-(5-bromopyrazine-2-ylmethoxy)-5-phenyl-3-(2, 6-dichlorophenyl) isoxazole (1.02 g, 2.3 mmol) dissolved in anhydrous tetrahydrofuran (20 mL) was put into a reaction flask. Ethanol and liquid nitrogen were added into a 500 mL low-temperature Dewar flask to reduce the temperature to 78 C. N-butyllithium (1.7 ml, 2.7 mmol) was slowly added dropwise, and the mixture was stirred for 10 min. A solution of 3-methyl-5-(3-oxocyclobutyl) methyl benzoate (0.55 g, 2.5 mmol) dissolved in tetrahydrofuran (10 mL) was slowly added dropwise. The mixture was allowed to warm to room temperature to react overnight after reaction for 2 h at 78 C. After the reaction, the reaction solution was slowly poured into an ice-water mixture and extracted with ethyl acetate, with the ester layer washed with water (100 mL), dried over anhydrous magnesium sulfate, suction filtered, with the organic solvent distilled off under reduced pressure, and separated and purified by silica gel column chromatography gradient elution (PE:EA=10 1, v/v, PE is petroleum ether, EA is ethyl acetate) to give a white solid (3-(3-(5-((3-(2, 6-dichlorophenyl)-5-isopropylisoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl)-5-methyl toluate), 643 mg, yield 48%.

Synthesis of 3-(3-(5-((3-(2, 6-dichlorophenyl)-5-isopropylisoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl)-5-methyl benzoic acid

[0230] ##STR00073##

[0231] 3-(3-(5-((3-(2, 6-dichlorophenyl)-5-cyclopropylisoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl) methyl toluate (117 mg, 0.2 mmol, 1 eq) was dissolved in 20 mL THF and a solution of LiOH.Math.H.sub.2O (35 mg, 0.8 mmol, 4.2 eq) in water (5 mL) was added at 35 C. The mixture was stirred overnight. The organic solvent was removed by distillation under reduced pressure. The pH was adjusted to 5 with 1N hydrochloric acid. The mixture was extracted three times by adding ethyl acetate, dried with anhydrous magnesium sulfate, with the solvent removed by distillation under reduced pressure, and separated and purified by high-pressure preparative liquid chromatography. A Waters X Bridge C18 column (150 nm*4.6 nm*3.5 um) is used, with a mobile phase of acetonitrile and water, a flow rate of 18 mL/min, fractions collected with a gradient of 45%-75%, and most of the acetonitrile removed by concentrating. The mixture was treated by lyophilization with a lyophilizer to give a white powdery solid (3-(3-(5-((3-(2, 6-dichlorophenyl)-5-isopropylisoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl)-5-methyl benzoic acid), 46 mg, yield 40%.

[0232] As shown in FIG. 20, .sup.1H-NMR (400 MHz, DMSO-D6): 12.88 (1H, brs), 8.20 (1H, d, J=1.2 Hz), 8.08 (1H, d, J=1.2 Hz), 7.73 (1H, s), 7.63-7.60 (3H, m), 7.56-7.52 (1H, s), 7.37 (1H, s), 6.06 (1H, brs), 5.19 (2H, s), 3.61-3.54 (1H, m), 2.91-2.85 (2H, m), 2.45-2.40 (2H, m), 2.35 (3H, s), 1.38-1.36 (6H, d, J=8 Hz).

[0233] As shown in FIG. 21, 1.sup.3C-NMR (100 MHz, DMSO-D6): 176.9, 168.0, 159.3, 157.9, 153.5, 146.2, 135.1, 133.4, 133.0, 128.9, 127.6, 125.1, 109.9, 70.9, 56.3, 45.5, 29.8, 26.5, 21.3, 21.1.

[0234] As shown in FIG. 22, ESI-MS: m/z[M+H]+: Calcd. for C.sub.29H.sub.27Cl.sub.2N.sub.3O.sub.5: 567.1328, Found: 568.1412.

Embodiment 10: Synthesis of Compound TM-10

Synthesis of 3-(3-(5-((3-(2, 6-dichlorophenyl)-5-phenylisoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl)-5-methyl toluate

[0235] ##STR00074##

[0236] In a 100 ml three-necked flask under nitrogen protection, 4-(5-bromopyrazine-2-ylmethoxy)-5-phenyl-3-(2, 6-dichlorophenyl) isoxazole (1.03 g, 2.3 mmol) dissolved in anhydrous tetrahydrofuran (20 mL) was put into a reaction flask. Ethanol and liquid nitrogen were added into a 500 mL low-temperature Dewar flask to reduce the temperature to 78 C. N-butyllithium (1.7 ml, 2.7 mmol) was slowly added dropwise, and the mixture was stirred for 10 min. A solution of 3-methyl-5-(3-oxocyclobutyl) methyl benzoate (0.55 g, 2.5 mmol) dissolved in tetrahydrofuran (10 mL) was slowly added dropwise. The mixture was allowed to warm to room temperature to react overnight after reaction for 2 h at 78 C. After the reaction, the reaction solution was slowly poured into an ice-water mixture and extracted with ethyl acetate, with the ester layer washed with water (100 mL), dried over anhydrous magnesium sulfate, suction filtered, with the organic solvent distilled off under reduced pressure, and separated and purified by silica gel column chromatography gradient elution (PE:EA=10:1, v/v) to obtain a white solid (3-(3-(5-((3-(2, 6-dichlorophenyl)-5-phenylisoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl)-5-methyl toluate) 496 mg, 35% yield.

Synthesis of 3-(3-(5-((3-(2, 6-dichlorophenyl)-5-phenylisoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl)-5-methyl benzoic acid

[0237] ##STR00075##

[0238] 3-(3-(5-((3-(2, 6-dichlorophenyl)-5-phenylisoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl)-5-methyl toluate (123 mg, 0.2 mmol, 1 eq) was dissolved in 20 mL THF and a solution of LiOH.Math.H.sub.2O (35 mg, 0.8 mmol, 4.2 eq) in water (5 mL) was added at 35 C. The mixture was stirred overnight. The organic solvent was removed by distillation under reduced pressure. The pH was adjusted to 5 with 1N hydrochloric acid. The mixture was extracted three times by adding ethyl acetate, dried with anhydrous magnesium sulfate, with the solvent removed by distillation under reduced pressure, and separated and purified by high-pressure preparative liquid chromatography. A Waters X Bridge C18 column (150 nm*4.6 nm*3.5 um) is used, with a mobile phase of acetonitrile and water, a flow rate of 18 mL/min, fractions collected with a gradient of 45%-75%, and most of the acetonitrile removed by concentrating. The mixture was treated by lyophilization with a lyophilizer to give a white powdery solid (3-(3-(5-((3-(2, 6-dichlorophenyl)-5-phenylisoxazol-4-yl) methoxy) pyrazine-2-yl)-3-hydroxycyclobutyl)-5-methyl benzoic acid), 37 mg, yield 31%.

[0239] As shown in FIG. 23, .sup.1H-NMR (400 MHz, DMSO-D6): 12.89 (1H, s), 8.14 (1H, d, J=1.6 Hz), 8.09 (1H, d, J=1.6 Hz), 7.99-7.96 (3H, m), 7.73 (1H, s), 7.67-7.65 (5H, m), 7.61-7.57 (2H, m), 7.37 (1H, s), 6.06 (1H, s), 5.38 (2H, s), 3.33-3.28 (1H, m), 2.91-2.86 (2H, m), 2.45-2.40 (2H, m), 2.35 (3H, s).

[0240] As shown in FIG. 24, 1.sup.3C-NMR (100 MHz, DMSO-D6): 168.4, 168.0, 160.4, 157.8, 153.7, 146.2, 135.2, 133.3, 131.6, 130.0, 129.0, 127.7, 127.2, 125.1, 111.5, 70.9, 57.0, 45.5, 29.8, 21.3.

[0241] As shown in FIG. 25, ESI-MS: m/z[M+H]+: Calcd. for C.sub.32H.sub.25Cl.sub.2N.sub.3O.sub.5: 601.1171, Found: 602.1249.