6-OXO-1,6-DIHYDROPYRIDAZINE PRODRUG DERIVATIVE, PREPARATION METHOD THEREFOR, AND APPLICATION THEREOF IN MEDICINE

Abstract

Specifically, the present invention relates to the 6-oxo-1,6-dihydropyridazine prodrug derivative shown in general formula (I), a preparation method therefor, a pharmaceutical composition containing the derivative, a use thereof as a NaV inhibitor, and a use thereof in the preparation of a drug for the treatment and/or prevention of pain and pain-related diseases.

##STR00001##

Claims

1. A compound of formula (I) or a tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or a pharmaceutically acceptable salt thereof, ##STR00095## wherein: M is selected from the group consisting of O atom, CR.sup.4R.sup.5 and S atom; ring A is an aryl or heteroaryl; each R.sup.1 is identical or different and each is independently selected from the group consisting of hydrogen atom, halogen, alkyl, deuterated alkyl, alkoxy, deuterated alkoxy, haloalkyl, haloalkoxy, cyano, amino, nitro, hydroxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl; each R.sup.2 is identical or different and each is independently selected from the group consisting of hydrogen atom, halogen, alkyl, deuterated alkyl, alkoxy, deuterated alkoxy, haloalkyl, haloalkoxy, cyano, amino, nitro, hydroxy, hydroxyalkyl, cycloalkyl, cycloalkyloxy, heterocyclyl, aryl and heteroaryl, wherein the alkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl are each optionally substituted by one or more substituents selected from the group consisting of alkyl, haloalkyl, halogen, amino, nitro, cyano, hydroxy, alkoxy, haloalkoxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl; each R.sup.3 is identical or different and each is independently selected from the group consisting of hydrogen atom, halogen, alkyl, alkoxy, haloalkyl, cyano, amino, nitro, hydroxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl; R.sup.4 and R.sup.5 are identical or different and are each independently selected from the group consisting of hydrogen atom, deuterium atom, halogen, alkyl, alkoxy, haloalkyl, cyano, amino, nitro, hydroxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl; R.sup.w is selected from the group consisting of hydrogen atom, alkyl, —C(O)R.sup.6, —S(O).sub.2OH, —S(O).sub.2O.sup.−Q.sup.+, —PO(OH).sub.2, —PO(OH)O.sup.−Q.sup.+, —PO(O.sup.−).sub.22Q.sup.+ and —PO(O.sup.−).sub.2W.sup.2+; Q.sup.+ is a pharmaceutically acceptable monovalent cation; W.sup.2+ is a pharmaceutically acceptable divalent cation; R.sup.6 is selected from the group consisting of alkyl, alkoxy, alkenyl, carboxy and carboxylate, wherein the alkyl, alkoxy and alkenyl are each optionally substituted by one or more substituents selected from the group consisting of hydroxy, amino, carboxy and carboxylate; n is 0, 1, 2, 3 or 4; s is 0, 1, 2, 3 or 4; and t is 0, 1 or 2.

2. The compound of formula (I) or the tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or the pharmaceutically acceptable salt thereof according to claim 1, wherein ring A is a phenyl or pyridyl.

3. The compound of formula (I) or the tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or the pharmaceutically acceptable salt thereof according to claim 1, wherein R.sup.w is selected from the group consisting of hydrogen atom, —C(O)-alkyl, —C(O)-alkoxy, —C(O)-alkylene-COOH, —C(O)-alkenylene-COOH, —C(O)—COOH, —S(O).sub.2OH and —C(O)-alkylene-NH.sub.2, wherein the alkyl, alkoxy, alkylene and alkenylene are each optionally substituted by one or more hydroxys.

4. The compound of formula (I) or the tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or the pharmaceutically acceptable salt thereof according to claim 1, wherein R.sup.w is selected from the group consisting of hydrogen atom, —C(O)CH.sub.3, —C(O)CH(OH)CH.sub.3, —C(O)CH(CH.sub.3).sub.2, —C(O)OCH.sub.2CH.sub.3, —C(O)CH.sub.2COOH, —C(O)CH.sub.2CH.sub.2COOH, —C(O)CH(OH)CH.sub.2COOH, —C(O)CH.sub.2CH(OH)COOH, —C(O)CH(OH)CH(OH)COOH, —C(O)—CH═CH—COOH, —C(O)—COOH, —S(O).sub.2OH and —C(O)CH.sub.2NH.sub.2.

5. The compound of formula (I) or the tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or the pharmaceutically acceptable salt thereof according to any one of claim 1, wherein M is an O.

6. The compound of formula (I) or the tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or the pharmaceutically acceptable salt thereof according to claim 1, being a compound of formula (II) or a tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or a pharmaceutically acceptable salt thereof, ##STR00096## wherein: each R.sup.1 is identical or different and each is independently selected from the group consisting of hydrogen atom, halogen, alkyl, deuterated alkyl, alkoxy, deuterated alkoxy, haloalkyl, haloalkoxy, cyano, amino, nitro, hydroxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl; each R.sup.2 is identical or different and each is independently selected from the group consisting of hydrogen atom, halogen, alkyl, deuterated alkyl, alkoxy, deuterated alkoxy, haloalkyl, haloalkoxy, cyano, amino, nitro, hydroxy, hydroxyalkyl, cycloalkyl, cycloalkyloxy, heterocyclyl, aryl and heteroaryl, wherein the alkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl are each optionally substituted by one or more substituents selected from the group consisting of alkyl, haloalkyl, halogen, amino, nitro, cyano, hydroxy, alkoxy, haloalkoxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl: each R.sup.3 is identical or different and each is independently selected from the group consisting of hydrogen atom, halogen, alkyl, alkoxy, haloalkyl, cyano, amino, nitro, hydroxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl: R.sup.w is selected from the group consisting of hydrogen atom, alkyl, —C(O)R.sup.6, —S(O).sub.2OH, —S(O).sub.2O.sup.−Q.sup.+, —PO(OH).sub.2, —PO(OH)O.sup.−Q.sup.+, —PO(O.sup.−).sub.22Q.sup.+ and —PO(O.sup.−).sub.2W.sup.2+; Q.sup.+ is a pharmaceutically acceptable monovalent cation; W.sup.2+ is a pharmaceutically acceptable divalent cation; R.sup.6 is selected from the group consisting of alkyl, alkoxy, alkenyl, carboxy and carboxylate, wherein the alkyl, alkoxy and alkenyl are each optionally substituted by one or more substituents selected from the group consisting of hydroxy, amino, carboxy and carboxylate; n is 0, 1, 2, 3 or 4: s is 0, 1, 2, 3 or 4; and t is 0, 1 or 2.

7. The compound of formula (I) or the tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or the pharmaceutically acceptable salt thereof according to claim 1, being a compound of formula (IIaa) or a tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or a pharmaceutically acceptable salt thereof, ##STR00097## wherein: R.sup.1a is a halogen; R.sup.1b is a haloalkyl; and each R.sup.2 is identical or different and each is independently selected from the group consisting of hydrogen atom, halogen, alkyl, deuterated alkyl, alkoxy, deuterated alkoxy, haloalkyl, haloalkoxy, cyano, amino, nitro, hydroxy, hydroxyalkyl, cycloalkyl, cycloalkyloxy, heterocyclyl, aryl and heteroaryl, wherein the alkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl are each optionally substituted by one or more substituents selected from the group consisting of alkyl, haloalkyl, halogen, amino, nitro, cyano, hydroxy, alkoxy, haloalkoxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl; each R.sup.3 is identical or different and each is independently selected from the group consisting of hydrogen atom, halogen, alkyl, alkoxy, haloalkyl, cyano, amino, nitro, hydroxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl: R.sup.w is selected from the group consisting of hydrogen atom, alkyl, —C(O)R.sup.6, —S(O).sub.2OH, —S(O).sub.2O.sup.−Q.sup.+, —PO(OH).sub.2, —PO(OH)O.sup.−Q.sup.+, —PO(O.sup.−).sub.22Q.sup.+ and —PO(O.sup.−).sub.2W.sup.2+ Q.sup.+ is a pharmaceutically acceptable monovalent cation; W.sup.2+ is a pharmaceutically acceptable divalent cation; R.sup.6 is selected from the group consisting of alkyl, alkoxy, alkenyl, carboxy and carboxylate, wherein the alkyl, alkoxy and alkenyl are each optionally substituted by one or more substituents selected from the group consisting of hydroxy, amino, carboxy and carboxylate; s is 0, 1, 2, 3 or 4; and t is 0, 1 or 2.

8. The compound of formula (I) or the tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or the pharmaceutically acceptable salt thereof according to claim 1, wherein each R.sup.1 is identical or different and each is independently selected from the group consisting of hydrogen atom, halogen, alkyl and haloalkyl.

9. The compound of formula (I) or the tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or the pharmaceutically acceptable salt thereof according to claim 1, wherein each R.sup.2 is identical or different and each is independently selected from the group consisting of hydrogen atom, halogen, alkyl, alkoxy, deuterated alkoxy, haloalkyl, haloalkoxy, cycloalkyl and cycloalkyloxy.

10. The compound of formula (I) or the tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or the pharmaceutically acceptable salt thereof according to claim 1, wherein R.sup.3 is a hydrogen atom.

11. The compound of formula (I) or the tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or the pharmaceutically acceptable salt thereof according to claim 1, being a compound of formula (III) or a tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or a pharmaceutically acceptable salt thereof, ##STR00098## wherein: R.sup.w is selected from the group consisting of hydrogen atom, alkyl, —C(O)R.sup.6, —S(O).sub.2OH, —S(O).sub.2O.sup.−Q.sup.+, —PO(OH).sub.2, —PO(OH)O.sup.−Q.sup.+, —PO(O.sup.−).sub.22Q.sup.+ and —PO(O.sup.−).sub.2W.sup.2+; Q.sup.+ is a pharmaceutically acceptable monovalent cation; W.sup.2+ is a pharmaceutically acceptable divalent cation, R.sup.6 is selected from the group consisting of alkyl, alkoxy, alkenyl, carboxy and carboxylate, wherein the alkyl, alkoxy and alkenyl are each optionally substituted by one or more substituents selected from the group consisting of hydroxy, amino, carboxy and carboxylate.

12. The compound of formula (I) or the tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or the pharmaceutically acceptable salt thereof according to claim 1, being a compound of formula (IV) or a tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or a pharmaceutically acceptable salt thereof, ##STR00099## wherein: R.sup.7 is selected from the group consisting of alkyl, deuterated alkyl and cycloalkyl; and R.sup.w is selected from the group consisting of hydrogen atom, alkyl, —C(O)R.sup.6, —S(O).sub.2OH, —S(O).sub.2O.sup.−Q.sup.+, —PO(OH).sub.2, —PO(OH)O.sup.−Q.sup.+, —PO(O.sup.−).sub.22Q.sup.+ and —PO(O.sup.−).sub.2W.sup.2+; Q.sup.+ is a pharmaceutically acceptable monovalent cation; W.sup.2+ is a pharmaceutically acceptable divalent cation, R.sup.6 is selected from the group consisting of alkyl, alkoxy, alkenyl, carboxy and carboxylate, wherein the alkyl, alkoxy and alkenyl are each optionally substituted by one or more substituents selected from the group consisting of hydroxy, amino, carboxy and carboxylate.

13. The compound of formula (I) or the tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or the pharmaceutically acceptable salt thereof according to claim 1, selected from the group consisting of: ##STR00100## ##STR00101## ##STR00102## ##STR00103## ##STR00104## ##STR00105## ##STR00106## ##STR00107## ##STR00108## ##STR00109##

14. A method for preparing the compound of formula (I) or the tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or the pharmaceutically acceptable salt thereof according to claim 1, comprising a step of: ##STR00110## reacting a compound of formula (IA) with R.sup.w—X, ##STR00111## or sulfur trioxide pyridine to obtain the compound of formula (I); wherein: R.sup.w is —C(O)R.sup.6 or —S(O).sub.2OH; X is a halogen or hydroxy; is a single bond or double bond; and M is selected from the group consisting of O atom, CR.sup.4R.sup.5 and S atom: ring A is an aryl or heteroaryl; each R.sup.1 is identical or different and each is independently selected from the group consisting of hydrogen atom, halogen, alkyl, deuterated alkyl, alkoxy, deuterated alkoxy, haloalkyl, haloalkoxy, cyano, amino, nitro, hydroxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl; each R.sup.2 is identical or different and each is independently selected from the group consisting of hydrogen atom, halogen, alkyl, deuterated alkyl, alkoxy, deuterated alkoxy, haloalkyl, haloalkoxy, cyano, amino, nitro, hydroxy, hydroxyalkyl, cycloalkyl, cycloalkyloxy, heterocyclyl, aryl and heteroaryl, wherein the alkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl are each optionally substituted by one or more substituents selected from the group consisting of alkyl, haloalkyl, halogen, amino, nitro, cyano, hydroxy, alkoxy, haloalkoxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl; each R.sup.3 is identical or different and each is independently selected from the group consisting of hydrogen atom, halogen, alkyl, alkoxy, haloalkyl, cyano, amino, nitro, hydroxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl; R.sup.4 and R.sup.5 are identical or different and are each independently selected from the group consisting of hydrogen atom, deuterium atom, halogen, alkyl, alkoxy, haloalkyl, cyano, amino, nitro, hydroxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl; R.sup.6 is selected from the group consisting of alkyl, alkoxy, alkenyl, carboxy and carboxylate, wherein the alkyl, alkoxy and alkenyl are each optionally substituted by one or more substituents selected from the group consisting of hydroxy, amino, carboxy and carboxylate; n is 0, 1, 2, 3 or 4: s is 0, 1, 2, 3 or 4; and t is 0, 1 or 2.

15. The method according to claim 14, further comprising a step of: ##STR00112## reacting a compound of formula (IB) with formaldehyde solution to obtain the compound of formula (IA); wherein: M is selected from the group consisting of O atom, CR.sup.4R.sup.5 and S atom; ring A is an aryl or heteroaryl; each R.sup.1 is identical or different and each is independently selected from the group consisting of hydrogen atom, halogen, alkyl, deuterated alkyl, alkoxy, deuterated alkoxy, haloalkyl, haloalkoxy, cyano, amino, nitro, hydroxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl; each R.sup.2 is identical or different and each is independently selected from the group consisting of hydrogen atom, halogen, alkyl, deuterated alkyl, alkoxy, deuterated alkoxy, haloalkyl, haloalkoxy, cyano, amino, nitro, hydroxy, hydroxyalkyl, cycloalkyl, cycloalkyloxy, heterocyclyl, aryl and heteroaryl, wherein the alkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl are each optionally substituted by one or more substituents selected from the group consisting of alkyl, haloalkyl, halogen, amino, nitro, cyano, hydroxy, alkoxy, haloalkoxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl; each R.sup.3 is identical or different and each is independently selected from the group consisting of hydrogen atom, halogen, alkyl, alkoxy, haloalkyl, cyano, amino, nitro, hydroxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl; R.sup.4 and R.sup.5 are identical or different and are each independently selected from the group consisting of hydrogen atom, deuterium atom, halogen, alkyl, alkoxy, haloalkyl, cyano, amino, nitro, hydroxy, hydroxyalkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl; n is 0, 1, 2, 3 or 4: s is 0, 1, 2, 3 or 4; and t is 0, 1 or 2.

16. A pharmaceutical composition, comprising the compound of formula (I) or the tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or the pharmaceutically acceptable salt thereof according to claim 1, and one or more pharmaceutically acceptable carriers, diluents or excipients.

17. A method of inhibiting a voltage-gated sodium channel in a subject in need thereof, the method comprising: administering the compound of formula (I) or the tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or the pharmaceutically acceptable salt thereof according to claim 1 to the subject.

18. A method of treating and/or alleviating pain and pain-related diseases, multiple sclerosis, Charcot-Marie-Tooth syndrome, incontinence or cardiac arrhythmia in a subject in need thereof, the method comprising: administering the compound of formula (I) or the tautomer, mesomer, racemate, enantiomer, diastereomer thereof, or mixture thereof, or the pharmaceutically acceptable salt thereof according to claim 1 to the subject.

Description

DETAILED DESCRIPTION

[0264] The present disclosure will be further described with reference to the following examples, but the examples should not be considered as limiting the scope of the present disclosure.

EXAMPLES

[0265] The structures of the compounds were identified by nuclear magnetic resonance (NMR) and/or mass spectrometry (MS). NMR shifts (6) are given in 10.sup.−6 (ppm). NMR is determined by a Bruker AVANCE-400 machine. The solvents for determination are deuterated-dimethyl sulfoxide (DMSO-d.sub.6), deuterated-chloroform (CDCl.sub.3) and deuterated-methanol (CD.sub.3OD), and the internal standard is tetramethylsilane (TMS).

[0266] MS was determined by an Agilent 1200/1290 DAD-6110/6120 Quadrupole MS liquid chromatograph/mass spectrometer (manufacturer: Agilent, MS model: 6110/6120 Quadrupole MS), waters ACQuity UPLC-QD/SQD (manufacturer: waters, MS model: waters ACQuity Qda Detector/waters SQ Detector), THERMO Ultimate 3000-Q Exactive (manufacturer: THERMO, MS model: THERMO Q Exactive).

[0267] High performance liquid chromatography (HPLC) was determined on an Agilent HPLC 1200DAD, Agilent HPLC 1200VWD and Waters HPLC e2695-2489 high pressure liquid chromatograph.

[0268] Chiral HPLC was determined on an Agilent 1260 DAD high performance liquid chromatograph.

[0269] Preparative chromatography was carried out on Waters 2545-2767, Waters 2767-SQ Detecor2, Shimadzu LC-20AP and Gilson GX-281 preparative chromatographs.

[0270] Chiral preparation was carried out on a Shimadzu LC-20AP preparative chromatograph.

[0271] CombiFlash rapid preparation instrument used was Combiflash Rf200 (TELEDYNE ISCO).

[0272] Yantai Huanghai HSGF254 or Qingdao GF254 silica gel plate was used as the thin-layer silica gel chromatography (TLC) plate. The dimension of the silica gel plate used in TLC was 0.15 mm to 0.2 mm, and the dimension of the silica gel plate used in product purification was 0.4 mm to 0.5 mm.

[0273] Yantai Huanghai 200 to 300 mesh silica gel was generally used as a carrier for silica gel column chromatography.

[0274] The average kinase inhibition rates and IC.sub.50 values were determined by a NovoStar microplate reader (BMG Co., Germany).

[0275] The known starting materials of the present disclosure can be prepared by the known methods in the art, or can be purchased from ABCR GmbH & Co. KG, Acros Organics, Aldrich Chemical Company, Accela ChemBio Inc., Dan Chemical Company etc.

[0276] Unless otherwise stated, the reactions were carried out under argon atmosphere or nitrogen atmosphere.

[0277] “Argon atmosphere” or “nitrogen atmosphere” means that a reaction flask is equipped with an argon or nitrogen balloon (about 1 L).

[0278] “Hydrogen atmosphere” means that a reaction flask is equipped with a hydrogen balloon (about 1 L).

[0279] Pressurized hydrogenation reaction was performed on a Parr 3916EKX hydrogenation instrument and a Qinglan QL-500 hydrogen generator or HC2-SS hydrogenation instrument.

[0280] In hydrogenation reactions, the reaction system was generally vacuumed and filled with hydrogen, and the above operation was repeated three times.

[0281] CEM Discover-S 908860 type microwave reactor was used in microwave reactions.

[0282] Unless otherwise stated, the solution refers to an aqueous solution.

[0283] Unless otherwise stated, the reaction temperature is room temperature from 20° C. to 30° C.

[0284] The reaction process in the examples was monitored by thin layer chromatography (TLC). The developing solvent used in the reactions, the eluent system in column chromatography and the developing solvent system in thin layer chromatography for purification of the compounds included: A: dichloromethane/methanol system, B: n-hexane/ethyl acetate system, C: petroleum ether/ethyl acetate system, D: acetone, E: dichloromethane/acetone system, F: ethyl acetate/dichloromethane system, G: ethyl acetate/dichloromethane/n-hexane, and H: ethyl acetate/dichloromethane/acetone. The ratio of the volume of the solvent was adjusted according to the polarity of the compounds, and a small quantity of alkaline reagent such as triethylamine or acidic reagent such as acetic acid could also be added for adjustment.

Example 1

5-Chloro-2-(4-fluoro-2-methylphenoxy)-N-(1-(hydroxymethyl)-6-oxo-1,6-dihydropyridazin-4-yl)-4-(trifluoromethyl)benzamide 1

[0285] ##STR00079## ##STR00080##

Step 1

5-Chloro-2-fluoro-4-(trifluoromethyl)benzoic acid 1b

[0286] 2,2,6,6-Tetramethylpiperidine (19.2 g, 135.93 mmol, Accela ChemBio (Shanghai) Inc.) was added to tetrahydrofuran (200 mL) under an argon atmosphere. The resulting solution was cooled to 0° C., then n-butyl lithium (1.6 M, 85.1 mL) was added dropwise within about 45 minutes at a controlled temperature below 3° C. The reaction solution was reacted at 0° C. for 1 hour, and then cooled to −78° C. Compound 1-chloro-4-fluoro-2-(trifluoromethyl)benzene 1a (18 g, 90.66 mmol, Shanghai Titan Scientific Co., Ltd.) was added dropwise, and the reaction solution was reacted for 3 hours. Excess dry ice was added, and the reaction solution was naturally warmed up to 0° C., followed by the addition of 150 mL of ice water. The reaction solution was separated into two phases. The aqueous phase was adjusted to pH 5 to 6 with concentrated hydrochloric acid and extracted with ethyl acetate (50 mL), and the organic phase was concentrated under reduced pressure. The crude product was washed with n-hexane (50 mL), then purified by silica gel column chromatography with eluent system A to obtain the title compound 1b (15 g, yield: 68%).

[0287] MS m/z (ESI): 241.1 [M−1].

Step 2

Methyl 5-chloro-2-fluoro-4-(trifluoromethyl)benzoate 1c

[0288] Compound 1b (5 g, 20.61 mmol) was added to thionyl chloride (49.2 g, 413.55 mmol), and the reaction solution was reacted at 80° C. for 2 hours. The reaction solution was concentrated under reduced pressure. The resulting oil was added dropwise to methanol (100 mL), and the reaction solution was reacted at room temperature for 1 hour. The reaction solution was concentrated under reduced pressure, and the resulting residue was purified by silica gel column chromatography with eluent system B to obtain the title compound 1c (2.78 g, yield: 52%).

Step 3

Methyl 5-chloro-2-(4-fluoro-2-methylphenoxy)-4-(trifluoromethyl)benzoate 1d

[0289] Compound 1c (2.78 g, 10.83 mmol), 4-fluoro-2-methyl-phenol (1.5 g, 11.89 mmol, Shanghai Bide Pharmatech Ltd.) and cesium carbonate (6 g, 18.41 mmol) were added to N,N-dimethylformamide (20 mL), and the reaction solution was reacted at 100° C. for 1 hour. The reaction solution was cooled and filtered. The filtrate was concentrated to obtain the target compound 1d (3.92 g), which was used directly in the next step without purification.

[0290] MS m/z (ESI): 363.1 [M+1].

Step 4

5-Chloro-2-(4-fluoro-2-methylphenoxy)-4-(trifluoromethyl)benzoic acid 1e

[0291] The crude compound 1d (3.92 g, 10.81 mmol) was dissolved in methanol (30 mL), followed by the addition of water (10 mL) and sodium hydroxide (1.3 g, 32.5 mmol), and the reaction solution was reacted for 16 hours. The reaction solution was concentrated, followed by the addition of 10 mL of water, and the pH was adjusted to 1 with concentrated hydrochloric acid. The resulting solution was extracted with ethyl acetate (20 mL×3), and the organic phase was dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under reduced pressure, and the resulting residue was purified by silica gel column chromatography with eluent system A to obtain the title compound 1e (3.67 g, yield: 97%).

[0292] MS m/z (ESI): 346.8 [M−1].

Step 5

5-Chloro-2-(4-fluoro-2-methylphenoxy)-4-(trifluoromethyl)benzoyl chloride 1f

[0293] Compound 1e (3.67 g, 10.52 mmol) was added to thionyl chloride (20 g, 168.1 mmol), and the reaction solution was reacted at 80° C. for 2 hours. The reaction solution was concentrated to obtain the crude title compound 1f (3.86 g), which was used directly in the next step without purification.

Step 6

5-Chloro-N-(6-chloropyridazin-4-yl)-2-(4-fluoro-2-methylphenoxy)-4-(trifluoromethyl)benzamide 1g

[0294] 4-Dimethylaminopyridine (130 mg, 1.05 mmol) and 6-chloropyridazin-4-amine (1.51 g, 11.57 mmol, Pharmablock Sciences (Nanjing), Inc.) were dissolved in pyridine (40 mL), and the resulting solution was dried over molecular sieves. The crude compound 1f (3.86 g, 10.51 mmol) was added, and the reaction solution was reacted for 16 hours under an argon atmosphere. The reaction solution was concentrated under reduced pressure, and the resulting residue was purified by silica gel column chromatography with eluent system B to obtain the title compound 1g (1.3 g, yield: 39%).

[0295] MS m/z (ESI): 460.0 [M+1].

Step 7

5-Chloro-2-(4-fluoro-2-methylphenoxy)-N-(6-oxo-1,6-dihydropyridazin-4-yl)-4-(trifluoromethyl)benzamide 1h

[0296] Compound 1g (1.3 g, 2.82 mmol) and potassium acetate (555 mg, 5.65 mmol) were added to acetic acid (20 mL), and the reaction solution was reacted at 130° C. for 3 hours. The reaction solution was concentrated, and the resulting residue was purified by silica gel column chromatography with eluent system B to obtain the title compound 1h (800 mg, yield: 64%).

[0297] MS m/z (ESI): 442.0 [M+1].

Step 8

5-Chloro-2-(4-fluoro-2-methylphenoxy)-N-(1-(hydroxymethyl)-6-oxo-1,6-dihydropyridazin-4-yl)-4-(trifluoromethyl)benzamide 1

[0298] Compound 1h (975 mg, 2.21 mmol) was added to methanol (12 mL), followed by the addition of formaldehyde solution (12 g, 147.87 mmol, 37 wt %, Sinopharm Chemical Reagent Co., Ltd.). The reaction solution was heated to reflux for 16 hours under an argon atmosphere. The reaction solution was concentrated under reduced pressure and filtered. The resulting filter cake was washed with water, and dried to obtain the title compound 1 (1.0 g, yield: 96%).

[0299] MS m/z (ESI): 472.0 [M+1].

[0300] .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ 11.11 (s, 1H), 8.08 (s, 1H), 7.91 (s, 1H), 7.10-7.22 (m, 2H), 7.04-7.10 (m, 3H), 6.66 (t, 1H), 5.23 (d, 2H), 2.13 (s, 3H).

Example 2

4-((4-(5-Chloro-2-(4-fluoro-2-methylphenoxy)-4-(trifluoromethyl)benzamido)-6-oxopyridazin-1(6H)-yl)methoxy)-4-oxobutanoic acid 2

[0301] ##STR00081##

[0302] Compound 1 (990 mg, 2.10 mmol) was added to dichloromethane (20 mL), followed by the addition of succinic anhydride (300 mg, 3.00 mmol, Sinopharm Chemical Reagent Co., Ltd.), 4-dimethylaminopyridine (40 mg, 0.32 mmol) and N,N-diisopropylethylamine (600 mg, 4.64 mmol). The reaction solution was reacted at 30° C. for 5 hours. The reaction solution was concentrated under reduced pressure, and the resulting residue was purified by preparative high performance liquid chromatography (Waters 2767-SQ Detecor2, eluent system: ammonium acetate, water, acetonitrile) to obtain the title compound 2 (yield: 68%).

[0303] MS m/z (ESI): 572.0 [M+1].

[0304] .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ 12.23 (s, 1H), 11.21 (s, 1H), 8.08 (s, 1H), 7.94 (d, 1H), 7.28 (d, 1H), 7.19 (d, 1H), 7.05-7.09 (m, 3H), 5.86 (s, 2H), 2.40-2.53 (m, 4H), 2.13 (s, 3H).

Example 3

(4-(5-Chloro-2-(4-fluoro-2-methylphenoxy)-4-(trifluoromethyl)benzamido)-6-oxopyridazin-1(6H)-yl)methyl isobutyrate 3

[0305] ##STR00082##

[0306] In accordance with the synthetic route in Example 2, the starting compound succinic anhydride was replaced with isobutyryl chloride (Sun Chemical Technology (Shanghai) Co., Ltd.), accordingly, the title compound 3 (60 mg, yield: 52%) was prepared.

[0307] MS m/z (ESI): 542.1 [M+1].

[0308] .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ 11.21 (s, 1H), 8.08 (s, 1H), 7.94 (s, 1H), 7.27 (s, 1H), 7.19 (d, 1H), 7.05-7.09 (m, 3H), 5.87 (s, 2H), 2.50-2.60 (m, 1H), 2.13 (s, 3H), 1.03 (d, 6H).

Example 4

(4-(5-Chloro-2-(4-fluoro-2-methylphenoxy)-4-(trifluoromethyl)benzamido)-6-oxopyridazin-1(6H)-yl)methyl acetate 4

[0309] ##STR00083##

[0310] In accordance with the synthetic route in Example 2, the starting compound succinic anhydride was replaced with acetyl chloride (Sinopharm Chemical Reagent Co., Ltd.), accordingly, the title compound 4 (60 mg, yield: 55%) was prepared.

[0311] MS m/z (ESI): 514.1 [M+1].

[0312] .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ 11.21 (s, 1H), 8.08 (s, 1H), 7.94 (s, 1H), 7.28 (d, 1H), 7.19 (d, 1H), 7.05-7.09 (m, 3H), 5.85 (s, 2H), 2.13 (s, 3H), 2.01 (s, 3H).

Example 5

(4-(5-Chloro-2-(4-fluoro-2-methylphenoxy)-4-(trifluoromethyl)benzamido)-6-oxopyridazin-1(6H)-yl)methyl ethyl carbonate 5

[0313] ##STR00084##

[0314] In accordance with the synthetic route in Example 2, the starting compound succinic anhydride was replaced with ethyl chloroacetate (Sinopharm Chemical Reagent Co., Ltd.), accordingly, the title compound 5 (15 mg, yield: 13%) was prepared.

[0315] MS m/z (ESI): 544.1 [M+1].

[0316] .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ 11.22 (s, 1H), 8.09 (s, 1H), 7.94 (d, 1H), 7.28 (d, 1H), 7.19 (d, 1H), 7.05-7.09 (m, 3H), 5.89 (s, 2H), 4.12 (q, 2H), 2.13 (s, 3H), 1.18 (t, 3H).

Example 6

4-((4-(5-Chloro-2-(4-fluoro-2-methoxyphenoxy)-4-(trifluoromethyl)benzamido)-6-oxopyridazin-1(6H)-yl)methoxy)-4-oxobutanoic acid 6

[0317] ##STR00085## ##STR00086##

Step 1

5-Chloro-2-fluoro-4-(trifluoromethyl)benzoyl chloride 6a

[0318] Compound 1b (5.00 g, 20.6 mmol) was added to 15 mL of thionyl chloride, and the reaction solution was reacted at 80° C. for 2 hours. The reaction solution was concentrated under reduced pressure to obtain the crude title compound 6a (5.38 g), which was used directly in the next step without purification.

Step 2

5-Chloro-2-fluoro-N-(6-oxo-1,6-dihydropyridazin-4-yl)-4-(trifluoromethyl)benzamide 6b

[0319] 5-Aminopyridazin-3-one (3.06 g, 24.8 mmol, prepared according to the method disclosed in Example 386 on page 100 of the description of the patent application “WO2016004417”) was dissolved in 40 mL of N-methylpyrrolidone. The resulting solution was cooled to 0° C., and sodium hydride (2.06 g, 51.5 mmol, purity: 60%) was slowly add in batches. The reaction solution was stirred at 0° C. for 30 minutes. Compound 6a (5.38 g, 20.6 mmol) was dissolved in 3 mL of N-methylpyrrolidone, and the resulting solution was slowly added dropwise to the above reaction solution, which was then stirred at room temperature overnight. The reaction solution containing the title compound 6b was used directly in the next step without purification.

Step 3

5-Chloro-2-(4-fluoro-2-methoxyphenoxy)-N-(6-oxo-1,6-dihydropyridazin-4-yl)-4-(trifluoromethyl)benzamide 6c

[0320] 4-Fluoro-2-methoxyphenol (2.34 g, 16.5 mmol, Tokyo Chemical Industry (Shanghai) Co., Ltd.) and cesium carbonate (6.71 g, 20.6 mmol, Accela ChemBio (Shanghai) Inc.) were added directly to the reaction solution containing compound 6b. The reaction solution was reacted at 60° C. overnight, and then cooled to room temperature. Ethyl acetate (250 mL) was added, and the reaction solution was washed with water (100 mL×3). The organic phase was dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under reduced pressure, and the resulting residue was purified by silica gel column chromatography with eluent system B to obtain the title compound 6c (3.0 g, yield: 32%).

[0321] MS m/z (ESI): 458.1 [M+1].

[0322] .sup.1H NMR (400 MHz, DMSO-d.sub.6): δ 12.87 (s, 1H), 11.03 (s, 1H), 8.05 (s, 1H), 7.92 (s, 1H), 7.27 (dd, 1H), 7.22 (s, 1H), 7.15 (dd, 1H), 7.00 (s, 1H), 6.87-6.82 (m, 1H), 3.71 (s, 3H).

Step 4

5-Chloro-2-(4-fluoro-2-methoxyphenoxy)-N-(1-(hydroxymethyl)-6-oxo-1,6-dihydropyridazin-4-yl)-4-(trifluoromethyl)benzamide 6d

[0323] Compound 6c (3.00 g, 6.55 mmol) was added to 30 mL of methanol, followed by the addition of formaldehyde solution (30 mL, 37 wt %, Sinopharm Chemical Reagent Co., Ltd.). The reaction solution was heated to reflux for 16 hours under an argon atmosphere. The reaction solution was concentrated under reduced pressure and filtered. The resulting filter cake was dried to obtain the title compound 6d (2.90 g, yield: 910%).

[0324] MS m/z (ESI): 488.2 [M+1].

Step 5

4-((4-(5-Chloro-2-(4-fluoro-2-methoxyphenoxy)-4-(trifluoromethyl)benzamido)-6-oxopyridazin-1(6H)-yl)methoxy)-4-oxobutanoic acid 6

[0325] Compound 6d (2.90 g, 5.94 mmol) was added to 50 mL of dichloromethane, followed by the addition of succinic anhydride (893 mg, 8.92 mmol, Sinopharm Chemical Reagent Co., Ltd.), 4-dimethylaminopyridine (110 mg, 0.89 mmol) and N,N-diisopropylethylamine (1.54 g, 11.92 mmol). The reaction solution was reacted at 30° C. overnight. The reaction solution was concentrated under reduced pressure, and the resulting residue was purified by preparative high performance liquid chromatography (Waters 2767-SQ Detecor2, eluent system: ammonium acetate, water, acetonitrile) to obtain the title compound 6 (2.8 g, yield: 80%).

[0326] MS m/z (ESI): 588.1 [M+1].

[0327] 1H NMR (400 MHz, DMSO-d.sub.6) δ 12.22 (s, 1H), 11.16 (s, 1H), 8.03 (s, 1H), 7.97 (d, 1H), 7.31 (s, 1H), 7.24 (dd, 1H), 7.11 (dd, 1H), 6.97 (s, 1H), 6.84-7.79 (m, 1H), 5.87 (s, 2H), 2.52-2.41 (m, 4H), 2.03 (s, 3H).

Example 7

4-((4-(5-Chloro-2-(4-fluoro-2-(methoxy-d.SUB.3.)phenoxy)-4-(trifluoromethyl)benzamido)-6-oxopyridazin-1(6H)-yl)methoxy)-4-oxobutanoic acid 7

[0328] ##STR00087## ##STR00088##

Step 1

1-Bromo-4-fluoro-2-(methoxy-d.SUB.3.)benzene 7b

[0329] 2-Bromo-5-fluorophenol 7a (1 g, 5.2 mmol, Accela ChemBio (Shanghai) Inc.), deuterated methyl iodide (911 mg, 6.3 mmol, Sun Chemical Technology (Shanghai) Co., Ltd.) and potassium carbonate (1.45 g, 10.5 mmol) were added to N,N-dimethylformamide (10 mL). The reaction solution was stirred and reacted for 6 hours. The reaction solution was cooled to room temperature. Ethyl acetate (20 mL) was added, and the reaction solution was washed with water (20 mL×3). The organic phases were combined, dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under reduced pressure, and the resulting residue was purified by silica gel column chromatography with eluent system A to obtain the title compound 7b (840 mg, yield: 71%).

[0330] .sup.1H NMR (400 MHz, CDCl.sub.3): δ 7.49-7.45 (m, 1H), 6.66-6.57 (m, 2H).

Step 2

4-Fluoro-2-(methoxy-d.SUB.3.)phenol 7c

[0331] Compound 7b (840 mg, 4 mmol) and triisopropyl borate (987 mg, 5.25 mmol, Shanghai Titan Scientific Co., Ltd.) were added to a mixed solution of tetrahydrofuran/toluene (150 mL/30 mL). The air in the reaction flask was replaced with argon. The reaction solution was cooled to −78° C., then n-butyl lithium (1.6 M, 3.8 mL, 6.1 mmol) was slowly added dropwise within 20 minutes. The reaction solution was naturally warmed up to room temperature and stirred overnight. The reaction solution was cooled to 0° C. in an ice bath. Methanol (50 mL) was added, and hydrogen peroxide (30 wt %, 10 mL) and 10% sodium hydroxide solution (40 mL) were added dropwise. The reaction solution was stirred at room temperature for 1 hour. Saturated sodium thiosulfate solution (50 mL) was slowly added dropwise, and the reaction solution was extracted with ethyl acetate (200 mL×3). The organic phase was washed with saturated sodium bicarbonate solution (150 mL), dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under reduced pressure, and the resulting residue was purified by silica gel column chromatography with eluent system B to obtain the title compound 7c (570 mg, yield: 97%).

[0332] MS m/z (ESI): 144.0 [M−1].

[0333] .sup.1H NMR (400 MHz, DMSO-d.sub.6): δ 8.89 (s, 1H), 6.85-6.82 (m, 1H), 6.76-6.72 (m, 1H), 6.59-6.54 (m, 1H).

Step 3

5-Chloro-2-(4-fluoro-2-(methoxy-d.SUB.3.)phenoxy)-N-(6-oxo-1,6-dihydropyridazin-4-yl)-4-(trifluoromethyl)benzamide 7d

[0334] Compound 6b (1 g, 2.98 mmol), compound 7c (433 mg, 2.98 mmol) and cesium carbonate (1.02 g, 3.13 mmol, Accela ChemBio (Shanghai) Inc.) were added to N-methylpyrrolidone (10 mL). The reaction solution was reacted at 80° C. for 3 hours, and cooled to room temperature. Ethyl acetate (20 mL) was added, and the reaction solution was washed with water (10 mL×3). The organic phases were combined, dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under reduced pressure, and the resulting residue was purified by silica gel column chromatography with eluent system B to obtain the title compound 7d (280 mg, yield: 20%).

[0335] MS m/z (ESI): 461.0 [M−1].

[0336] .sup.1H NMR (400 MHz, DMSO-d.sub.6): δ 12.87 (s, 1H), 11.03 (s, 1H), 8.06 (s, 1H), 7.93 (d, 1H), 7.29-7.23 (m, 2H), 7.16-7.13 (m, 1H), 7.01 (s, 1H), 6.88-6.83 (m, 1H).

Step 4

5-Chloro-2-(4-fluoro-2-(methoxy-d.SUB.3.)phenoxy)-N-(1-(hydroxymethyl)-6-oxo-1,6-dihydropyridazin-4-yl)-4-(trifluoromethyl)benzamide 7e

[0337] Compound 7d (6.1 g, 13.2 mmol) was added to 60 mL of methanol, followed by the addition of formaldehyde solution (60 mL, 37 wt %, Sinopharm Chemical Reagent Co., Ltd.). The reaction solution was heated to reflux for 16 hours under an argon atmosphere. The reaction solution was concentrated under reduced pressure and filtered. The resulting filter cake was dried to obtain the title compound 7e (5.6 g, yield: 86%).

[0338] MS m/z (ESI): 491.2 [M+1].

Step 5

4-((4-(5-Chloro-2-(4-fluoro-2-(methoxy-d.SUB.3.)phenoxy)-4-(trifluoromethyl)benzamido)-6-oxopyridazin-1(6H)-yl)methoxy)-4-oxobutanoic acid 7

[0339] Compound 7e (3.43 g, 7 mmol) was added to 80 mL of dichloromethane, followed by the addition of succinic anhydride (1.05 g, 10.5 mmol, Sinopharm Chemical Reagent Co., Ltd.), 4-dimethylaminopyridine (1.09 g, 8.8 mmol) and N,N-diisopropylethylamine (1.81 g, 14 mmol). The reaction solution was reacted at 30° C. overnight. The reaction solution was concentrated under reduced pressure, and the resulting residue was purified by preparative high performance liquid chromatography (Waters 2767-SQ Detecor2, eluent system: ammonium acetate, water, acetonitrile) to obtain the title compound 7 (2.7 g, yield: 65%).

[0340] MS m/z (ESI): 589.0 [M−1], 591.0 [M+1].

[0341] .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ 12.21 (s, 1H), 11.93 (s, 1H), 8.07 (s, 1H), 8.02 (d, 1H), 7.34 (d, 1H), 7.30-7.26 (m, 1H), 7.16-7.13 (m, 1H), 7.01 (s, 1H), 6.88-6.83 (m, 1H), 5.91 (s, 2H), 2.67-2.46 (m, 4H).

Example 8

(4-(5-Chloro-2-(4-fluoro-2-methylphenoxy)-4-(trifluoromethyl)benzamido)-6-oxopyridazin-1(6H)-yl)methyl hydrogen sulfate 8

[0342] ##STR00089##

[0343] In accordance with the synthetic route in Example 2, the starting compound succinic anhydride was replaced with sulfur trioxide pyridine (Accela ChemBio (Shanghai) Inc.), accordingly, the title compound 8 (30 mg) was prepared.

[0344] MS m/z (ESI): 550.0 [M−1].

[0345] .sup.1H NMR (400 MHz, CD.sub.3OD) δ 7.98-7.97 (m, 2H), 7.52-7.51 (m, 1H), 7.12-7.09 (m, 1H), 7.06-6.97 (m, 3H), 5.88 (s, 2H), 2.21 (s, 3H).

Example 9

(E)-4-((4-(5-Chloro-2-(4-fluoro-2-methylphenoxy)-4-(trifluoromethyl)benzamido)-6-oxopyridazin-1(6H)-yl)methoxy)-4-oxobut-2-enoic acid 9

[0346] ##STR00090##

[0347] In accordance with the synthetic route in Example 2, the starting compound succinic anhydride was replaced with trans-butenedioic acid (Accela ChemBio (Shanghai) Inc.), accordingly, the title compound 9 (10 mg) was prepared.

[0348] MS m/z (ESI): 570.1 [M+1].

[0349] .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ 12.22 (s, 1H), 8.08 (s, 1H), 7.96 (s, 1H), 7.29 (s, 1H), 7.19 (d, 1H), 7.00-7.13 (m, 3H), 6.60-6.75 (m, 2H), 6.01 (s, 2H), 2.13 (s, 3H).

Example 10

3-((4-(5-Chloro-2-(4-fluoro-2-methylphenoxy)-4-(trifluoromethyl)benzamido)-6-oxopyridazin-1(6H)-yl)methoxy)-3-oxopropanoic acid 10

[0350] ##STR00091##

[0351] In accordance with the synthetic route in Example 2, the starting compound succinic anhydride was replaced with propanedioic acid (Accela ChemBio (Shanghai) Inc.), accordingly, the title compound 10 (13 mg) was prepared.

[0352] MS m/z (ESI): 558.0 [M+1].

[0353] .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ 12.22 (s, 1H), 8.09 (s, 1H), 7.95 (s, 1H), 7.29 (s, 1H), 7.20 (d, 1H), 7.00-7.13 (m, 3H), 5.91 (s, 2H), 3.41 (s, 2H), 2.13 (s, 3H).

Example 11

4-((4-(5-Chloro-2-(2-ethyl-4-fluorophenoxy)-4-(trifluoromethyl)benzamido)-6-oxopyridazin-1(6H)-yl)methoxy)-4-oxobutanoic acid 11

[0354] ##STR00092##

[0355] In accordance with the synthetic route in Example 6, the starting compound 4-fluoro-2-methoxyphenol of Step 3 was replaced with 2-ethyl-4-fluorophenol (Shanghai Bide Pharmatech Ltd.), accordingly, the title compound 11 (2.3 g) was prepared.

[0356] MS m/z (ESI): 584.0 [M−1].

[0357] .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ 12.23 (br, 1H), 11.25 (s, 1H), 8.12 (s, 1H), 7.98-7.98 (dd, 1H), 7.32-7.32 (d, 1H), 7.25-7.23 (d, 1H), 7.13-7.11 (m, 2H), 7.10 (s, 1H), 5.90 (s, 2H), 2.58-2.53 (m, 4H), 2.49-2.46 (m, 2H), 1.10-1.06 (t, 3H).

Example 12

(4-(5-Chloro-2-(4-fluoro-2-(methoxy-d.SUB.3.)phenoxy)-4-(trifluoromethyl)benzamido)-6-oxopyridazin-1(6H)-yl)methyl hydrogen sulfate 12

[0358] ##STR00093##

[0359] In accordance with the synthetic route in Example 7, the starting compound succinic anhydride of Step 5 was replaced with sulfur trioxide pyridine (Accela ChemBio (Shanghai) Inc.), accordingly, the title compound 12 (85 mg) was prepared.

[0360] MS m/z (ESI): 568.9 [M−1].

[0361] .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ 8.02 (s, 1H), 7.89 (d, 1H), 7.23-7.19 (m, 2H), 7.09-7.05 (m, 2H), 6.94 (s, 1H), 6.80-6.76 (m, 1H), 5.48 (s, 2H).

Example 13

(E)-4-((4-(5-Chloro-2-(4-fluoro-2-(methoxy-d.SUB.3.)phenoxy)-4-(trifluoromethyl)benzamido)-6-oxopyridazin-1(6H)-yl)methoxy)-4-oxobut-2-enoic acid 13

[0362] ##STR00094##

[0363] In accordance with the synthetic route in Example 7, the starting compound succinic anhydride of Step 5 was replaced with trans-butenedioic acid (Accela ChemBio (Shanghai) Inc.), accordingly, the title compound 13 (11 mg) was prepared.

[0364] MS m/z (ESI): 587.0 [M−1].

[0365] .sup.1H NMR (400 MHz, CD.sub.3OD) δ 7.95 (d, 1H), 7.88 (s, 1H), 7.46 (d, 1H), 7.18-7.14 (m, 1H), 6.95 (s, 1H), 6.92-6.89 (m, 1H), 6.79 (d, 1H), 6.71-6.66 (m, 1H), 6.56 (d, 1H), 6.02 (s, 2H).

Physical and Chemical Properties

[0366] The present disclosure will be further described with reference to the following test examples, but the test examples should not be considered as limiting the scope of the present disclosure.

Test Example 1. Solubility of the Compound of the Present Disclosure in PBS Solution (pH 7.4) at Room Temperature

[0367] 1. Experimental materials

[0368] Reagents: dimethyl sulfoxide (analytical grade), ethanol (analytical grade), acetonitrile (chromatographic grade), NaH.sub.2PO.sub.4.2H.sub.2O (analytical grade), Na.sub.2HPO.sub.4.12H.sub.2O (analytical grade), ammonium acetate (analytical grade), sodium hydroxide, sodium chloride (analytical grade).

[0369] Instrument: liquid chromatograph.

[0370] 2. Experimental procedures

[0371] 2.1 Formulation of the PBS solution (pH 7.4): 0.57 g of NaH.sub.2PO.sub.42.H.sub.2O, 5.55 g of Na.sub.2HPO.sub.4.12H.sub.2O and 6.48 g of NaCl were weighed, followed by the addition of ultra-pure water. The pH was adjusted to 7.4±0.05 with 1 M NaOH or 1 M HCl. Water was added until the volume reached 1 L. The PBS solution was stored in a refrigerator at 4° C. (the storage life was 6 months).

[0372] 2.2 Formulation of the solution of the compound in PBS 7.4: An appropriate amount of the test compound was weighed, and dissolved in DMSO or a mixed solution of DMSO:acetonitrile:ethanol (1:1:1) to obtain a 10 mM stock solution of the test compound. 10 μL of the stock solution of the test compound and 990 μL of the PBS solution (pH 7.4) were precisely measured and placed in a 2 mL sample vial and mixed well, and the DMSO concentration of the final solution was 1% (v/v). This solution was formulated in duplicate, shaken on a plate bed at room temperature for 24 hours, and centrifuged at 5000 rpm for 20 minutes. The supernatant was analyzed by the liquid chromatograph.

[0373] 2.3 Formulation of the reference solution: 10 μL of the stock solution of the test sample (concentration: 10 mM, dissolved in DMSO) and 990 μL of an organic mixed solvent (usually DMSO:acetonitrile:ethanol=1:1:1) were precisely measured and placed in a 2 mL sample vial, and mixed well to obtain a clear 100 μM sample solution. The solution was filtered through a 0.45 μm organic phase microporous filter membrane, and the filtrate was analyzed by the liquid chromatograph.

[0374] 3. Data processing

[0375] Solubility (μM)=peak area of the sample/peak area of the reference*concentration of the reference (μM)*sample solution dilution factor

[0376] The average of two measurements was used as the final solubility.

TABLE-US-00002 TABLE 1 Solubility of the compounds of the present disclosure in PBS solution (pH 7.4) PBS pH7.4 Example No. (μM)  1h 0.5 2 57.4  6c 0.44 6 44.92  7d 1.26 7 34.46 8 707.02 9 63.45 10  146.93 12  96.19 13  63.59

[0377] Conclusion: At room temperature, the solubility of compounds 1h, 6c and 7d in the PBS solution (pH 7.4) is poor, while the solubility of the prodrug compounds of the present disclosure in the PBS solution (pH 7.4) is greatly improved.

Biological Assay

Test Example 2. Pharmacokinetics Assay of the Compounds of the Present Disclosure in Rats

[0378] 1. Abstract

[0379] SD rats were used as test animals. The drug concentration in plasma at different time points was determined by LC/MS/MS method after oral administration of the compounds of Example 2, Example 6 and Example 7 to SD rats. The pharmacokinetic behavior of the compounds of the present disclosure was studied and evaluated in SD rats.

[0380] 2. Test protocol

[0381] 2.1 Test compounds

[0382] Compounds of Example 2, Example 6 and Example 7.

[0383] 2.2 Test animals

[0384] Forty SD rats (half male and half female, equally divided into ten groups) were purchased from Shanghai Jiesijie Laboratory Animal Co., LTD. (Certificate No.: SCXK(Shanghai) 2013-0006).

[0385] 2.3 Preparation of the test compound

[0386] An appropriate amount of the compound of Example 2 was weighed, followed by the addition of 5% of DMSO, 5% of tween 80 and 90% of normal saline successively to obtain a colorless, clear and transparent solution.

[0387] An appropriate amount of the compound of Example 2 was weighed, followed by the addition of 0.5% sodium carboxymethyl cellulose (containing 0.5% tween 80) to obtain a white homogeneous suspension.

[0388] An appropriate amount of the compound of Example 6 was weighed, and added to 200 mM (5% PVPK30+5% TPGS) Na.sub.2HPO.sub.4 solution (pH=9) to obtain a homogeneous suspension.

[0389] An appropriate amount of the compound of Example 7 was weighed, and added to 200 mM (5% PVPK30+5% TPGS) Na.sub.2HPO.sub.4 solution (pH=9) to obtain a homogeneous suspension.

[0390] 2.4 Administration

[0391] After an overnight fast, the SD rats were intragastrically administered the test compounds. Regarding to the compound of Example 2 (formulation: 5% of DMSO, 5% of tween 80 and 90% of normal saline), the administration dose was 2 mg/kg, the administration volume was 10 mL/kg, and the administration concentration was 0.2 mg/mL. Regarding to the compound of Example 2 (formulation: 0.5% sodium carboxymethyl cellulose (containing 0.5% tween 80)), the administration dose was 10, 30, 100 mg/kg, the administration volume was 10 mL/kg, and the administration concentration was 1, 3, 10 mg/mL. Regarding to the compound of Example 6, the administration dose was 100, 300, 900 mg/kg, the administration volume was 10 mL/kg, and the administration concentration was 10, 30, 90 mg/mL. Regarding to the compound of Example 7, the administration dose was 10, 30, 100 mg/kg, the administration volume was 10 mL/kg, and the administration concentration was 1, 3, 10 mg/mL.

[0392] 3. Process

[0393] After an overnight fast, the SD rats were intragastrically administered the test compounds. 0.2 ml of blood was taken from the orbit before the administration and at 0.5, 1.0, 2.0, 4.0, 6.0, 8.0, 11.0 and 24.0 hours after the administration. The samples were stored in heparinized tubes, and centrifuged for 10 minutes at 3500 rpm to separate the blood plasma. The plasma samples were stored at −20° C. The SD rats were fed 2 hours after the administration.

[0394] The content of the test compound in the plasma of SD rats after administration of the test compound at different concentrations was determined: 25 μL of SD rat plasma at each time point after the administration was taken, followed by the addition of 50 μL of the internal standard camptothecin solution (100 ng/mL) and 200 μL of acetonitrile. The resulting solution was vortex-mixed for 5 minutes, and centrifuged for 10 minutes (3700 rpm). 3.0 μL of the supernatant was taken from the plasma samples of the compound of Example 2 (the group at the administration dose of 2 mg/kg) for LC/MS/MS analysis. 2.0 μL of the supernatant was taken from the plasma samples of the compound of Example 2 (the group at the administration dose of 10, 30, or 100 mg/kg) for LC/MS/MS analysis. 0.2 μL of the supernatant was taken from the plasma samples of the compound of Example 6 for LC/MS/MS analysis. 1 μL of the supernatant was taken from the plasma samples of the compound of Example 7 for LC/MS/MS analysis.

[0395] 4. Results of pharmacokinetic parameters in SD rats

[0396] After the intragastrical administration, the plasma samples were analyzed using LC/MS/MS to determine the concentration of compound 2 and compound 1h, the concentration of compound 6 and compound 6c, as well as the concentration of compound 7 and compound 7d. The compounds of Example 2, Example 6 and Example 7 were not detected in the rats. The following data are the pharmacokinetic data of metabolite compounds 1h, 6c and 7d.

TABLE-US-00003 TABLE 2 Pharmacokinetic parameters of the compounds of the present disclosure in rats Plasma Area under Residence concentration curve Half-life time Test Compound being Cmax AUC T1/2 MRT compound Dose analyzed (ng/mL) (ng/mL * h) (h) (h) Example 2  2 mpk Compound 1h  374 ± 69.9  5680 ± 2170 19.0 ± 14.8 28.4 ± 21.5 Example 2  10 mpk Compound 1h  568 ± 184  9336 ± 5628 — — Example 2  30 mpk Compound 1h 1196 ± 372  19878 ± 9629 — — Example 2 100 mpk Compound 1h 2148 ± 794  41378 ± 17825 — — Example 6 100 mpk Compound 6c 6128 ± 2067  67383 ± 36193 4.46 ± 1.57 7.84 ± 2.11 Example 6 300 mpk Compound 6c 9573 ± 3392 113517 ± 20151 19.5 ± 21.6 28.6 ± 29.9 Example 6 900 mpk Compound 6c 7737 ± 1657 117947 ± 28070 76.4 ± 91.9  110 ± 131 Example 7  10 mpk Compound 7d  945 ± 291.0  11027 ± 3704 6.66 ± 2.36 10.5 ± 2.78 Example 7  30 mpk Compound 7d 2623 ± 602.1  34937 ± 8573   10 ± 5.73   15 ± 7.56 Example 7 100 mpk Compound 7d 5178 ± 555  92124 ± 12300 18.9 ± 7.6 28.0 ± 10.3

[0397] Conclusion: The above research results confirm that in rats, the compound of Example 2 was converted into compound 1h in vivo; the compound of Example 6 was converted into compound 6c in vivo; and the compound of Example 7 was converted into compound 7d in vivo. Moreover, the compounds of the present disclosure are well absorbed, and have a significant pharmacokinetic advantage.

Test Example 3. Determination of the Inhibitory Activity of the Compounds of the Present Disclosure on Na.SUB.V.1.8

[0398] The purpose of the experiment is to investigate the effect of the compounds on Na.sub.V1.8 ion channel in an in vitro experiment, wherein the Na.sub.V1.8 ion channel is stably expressed on HEK293 cells. After the Na.sub.V1.8 current becomes stable, the Na.sub.V1.8 currents before and after the administration of the compound are compared so as to obtain the effect of the compound on the Na.sub.V1.8 ion channel.

[0399] 1. Experimental materials and instruments

[0400] 1) Patch clamp amplifier: patch clamp PC-505B (WARNER instruments)/MultiClamp 700A (Axon instrument).

[0401] 2) Digital-to-analog converter: Digidata 1440A (Axon CNS)/Digidata 1550A (Axon instruments).

[0402] 3) Micro-manipulator: MP-225 (SUTTER instrument).

[0403] 4) Inverted microscope: TL4 (Olympus).

[0404] 5) Glass microelectrode puller: PC-10 (NARISHIGE).

[0405] 6) Microelectrode glass capillary: B12024F (Wuhan Weitan Scientific Instrument Co., Ltd.).

[0406] 7) Dimethyl sulfoxide (DMSO) D2650 (Sigma-Aldrich).

[0407] 8) TTX AF3014 (Affix Scientific).

[0408] 2. Experimental procedures

[0409] 2.1 Formulation of the compounds

[0410] Except for NaOH and KOH used for acid titration and base titration, all the compounds used for formulating the extracellular fluid and intracellular fluid were purchased from Sigma (St. Louis, Mo.). Extracellular fluid (mM): NaCl, 137; KCl, 4; CaCl.sub.2, 1.8; MgCl.sub.2, 1; HEPES, 10; glucose, 10; pH 7.4 (NaOH titration). Intracellular fluid (mM): aspartic acid, 140; MgCl.sub.2, 2; EGTA, 11; HEPES, 10; pH 7.2 (CsOH titration). All solutions of test compound and control compound contained 1 μM TTX.

[0411] The test compound was dissolved in dimethyl sulfoxide (DMSO) at a stock concentration of 9 mM. The stock solution of the test compound was dissolved in the extracellular fluid on the day of the test and formulated into the required concentration.

[0412] 2.2 Test process of the manual patch clamp

[0413] 1) The compound was formulated into solutions with specified concentrations, the solutions were added to the pipelines respectively in order from low to high concentration, and the pipelines were marked.

[0414] 2) The cell was transferred to the perfusion tank. A positive pressure was applied to the electrode. The tip of the electrode touched the cell. The three-way valve of the air extracting device was adjusted to a three-way state. A negative pressure was applied to the electrode, so that a high-resistance seal was formed between the electrode and the cell. The negative pressure was applied continuously, thereby causing the cell membrane to rupture and forming a current path.

[0415] 3) After the current for rupturing the cell membrane became stable, perfusion of different concentrations was carried out in sequence. Once the current was stable for at least one minute, perfusion of the next concentration was carried out. The duration of the perfusion of each concentration did not exceed five minutes.

[0416] 4) The perfusion tank was cleaned. The perfusion tank was rinsed with the drug solutions in order from high to low concentration, and the rinse duration for each concentration of drug solution was 20 seconds. The perfusion tank was finally rinsed with the extracellular fluid for 1 mintue.

[0417] 2.3 Test voltage equation (resting) and results

[0418] The cell was clamped at −80 mV. The cell was depolarized to 10 mV with a square wave lasting 10 milliseconds to obtain the Na.sub.V1.8 current. This procedure was repeated every 5 seconds. The maximum current caused by the square wave was measured. After the current became stable, the test compound was perfused. After the response became stable, the blocking intensity was calculated.

[0419] 3. Data analysis

[0420] The data was stored in the computer system for analysis. Data collection and analysis were carried out by pCLAMP 10 (Molecular Devices, Union City, Calif.), and the analysis results were reviewed by the administrator. Stable current means that the current changes within a limited range overtime. The magnitude of stable current was used to calculate the effect of the compound at the concentration.

[0421] The inhibitory activity of the compounds of the present disclosure on Na.sub.V1.8 was determined by the above test, and the resulting IC.sub.50 values are shown in Table 3.

TABLE-US-00004 TABLE 3 IC.sub.50 of the prodrug compounds and metabolites thereof of the present disclosure on inhibiting the Nav1.8 channel activity Example No. IC.sub.50 (nM) 1h 1.3 2  37.6 6c 1.3 6  3.9 7d 0.54 7  14.5

[0422] Conclusion: The prodrug compounds and metabolites thereof of the present disclosure have a significant inhibitory effect on the Na.sub.V1.8 channel activity.