Preparation method of cyclopentylpyridine derivative

Abstract

The invention provides a preparation method of a cyclopentylpyridine derivative. The cyclopentylpyridine derivative is prepared through Hofmann alkylation reaction, ester hydrolysis, rearrangement reaction, reduction reaction and condensation reaction. The route is high in yield, simple in post-treatment and suitable for industrial production.

Description

[0001] This application claims the priority of the Chinese patent application filed with the China Patent Office on July 28, 2023, with application number 202310944502.9 and invention name “Method for preparing cyclopentylpyridine derivatives”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention belongs to the field of pharmaceutical chemistry, and in particular relates to a method for preparing a KIF18A inhibitor. Background Art

[0003] KIF18A is a mitotic motor protein that regulates chromosome arrangement during cell mitosis, avoids errors in the mitotic process, and ensures the normal progress of mitosis.

[0004] The vast majority of human cells are diploid, and extensive cell cycle controls exist to ensure that this state is maintained during successive cell divisions. Despite these controls, errors can occur that result in the doubling of the entire genome, thereby converting a naturally diploid cell into a genetically unstable tetraploid cell. Cells that have undergone whole-genome doubling (WGD) (i.e., WGD + Cells) have carcinogenic potential, and the results (Nature. 2021Feb; 590(7846): 492-497) showed that KIF18A protein levels increased in WGD + In all 10 cell lines, KIF18A knockout increased the expression of - Cell line, WGD + Cell viability was significantly reduced, and live cell imaging showed that WGD occurred after KIF18A loss. + Breast cancer cells relative to WGD - Cells exhibited increased spindle length and chromosome hyperoscillation, which promoted chromosome shedding, capsule activation, and prolonged mitosis. These data revealed that loss of KIF18A impaired WGD + Therefore, KIF18A is an attractive therapeutic target and its inhibition may contribute to WGD + Specific targeting of tumors while sparing normal diploid cells that make up human tissues.

[0005] WO2024051812A describes a method for preparing compound 66 (i.e., the compound of formula (I) of the present application), a KIF18A inhibitor:

[0006]

[0007] In the process of synthesizing compound 66b from compound 66a, the two chlorine atoms of compound 66a lack selectivity, resulting in isomers or disubstituted products, resulting in poor purity of compound 66b and great difficulty in separation; in the second step of the reaction of synthesizing compound 66c from compound 66b, after the NH2DMB donor substituent in compound 66b is used to prepare 66b, the chlorine atom's leaving ability is weakened and the electrophilicity is reduced, so a Buchwald metal coupling reaction must be adopted. The process uses precious metal catalysis, which increases the cost and has a low yield (43%), making it unsuitable for industrial production; when preparing compound 66 from compound 66d and 4g, it is necessary to remove the TBS protecting group, which has poor atom economy. Summary of the invention

[0008] The invention relates to a novel method for preparing a compound of formula (I). The yield of the new route is significantly improved, and the total yield can reach more than 60%.

[0009] The present invention provides a method for preparing a compound represented by formula (I) or a pharmaceutically acceptable salt thereof, characterized in that:

[0010]

[0011] Prepared by condensation reaction of a compound of formula (II) with a compound of formula (III);

[0012]

[0013] Among them, R 1 , R 2 Each is independently halogen.

[0014] In some embodiments, the condensation reaction is carried out under the conditions of an organic base and a condensing agent, and the organic base is selected from any combination of one or more of triethylamine, N,N-diisopropylethylamine or N-methylmorpholine;

[0015] In some embodiments, the condensing agent is selected from 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate, O-benzotriazole-tetramethyluronium hexafluorophosphate, 6-chlorobenzotriazole-1,1,3,3-tetramethyluronium hexafluorophosphate, benzotriazol-1-yl-oxytripyrrolidinophosphorus hexafluorophosphate or 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride;

[0016] In some embodiments, the solvent for the condensation reaction is selected from any combination of one or more of N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone.

[0017] In some embodiments, the compound of formula (II) is prepared by reduction reaction of a compound of formula (IV),

[0018]

[0019] Among them, R 1 , R 2 and R 3 Each is independently halogen.

[0020] In some embodiments, the reduction reaction is carried out under the conditions of a catalyst and a reducing agent, and the catalyst is selected from palladium black, Pd / C, Pd(OH)2 / C, PdCl2 / C, Raney nickel or Pt / C;

[0021] In some embodiments, the reducing agent is selected from one or more of hydrogen, formic acid, formamide, ammonium formate, hydrazine hydrate and cyclohexene;

[0022] In some embodiments, the reduction reaction solvent is selected from any combination of one or more selected from methanol and ethanol.

[0023] In some embodiments, the compound of formula (IV) is prepared by rearrangement reaction of the compound of formula (V),

[0024]

[0025] Among them, R 1 , R 2 and R 3 Each is independently halogen.

[0026] In some embodiments, the rearrangement reaction is carried out in the presence of an azide reagent and an organic base, wherein the azide reagent is selected from sodium azide, trimethylsilyl azide (TMSA), diphenylphosphoryl azide (DPPA) or tetramethylguanidine azide (TMGA);

[0027] In some embodiments, the organic base is selected from triethylamine, N,N-diisopropylethylamine or N-methylmorpholine;

[0028] In some embodiments, the solvent for the rearrangement reaction is selected from any combination of one or more of toluene, xylene, 1,4-dioxane, 2-methyltetrahydrofuran, and ethylene glycol dimethyl ether.

[0029] In some embodiments, the compound of formula (V) is prepared by ester hydrolysis of the compound of formula (VI).

[0030]

[0031] Among them, R 1 , R 2 and R 3 Each is independently halogen; R 4 C 1-4alkyl.

[0032] In some embodiments, the ester hydrolysis reaction is carried out under alkaline conditions, and the base is selected from sodium hydroxide, potassium hydroxide or lithium hydroxide;

[0033] In some embodiments, the ester hydrolysis reaction solvent is selected from any combination of one or more of methanol, ethanol, and tetrahydrofuran.

[0034] In some embodiments, the compound of formula (VI) is prepared by a Hofmann alkylation reaction of a compound of formula (VII) with a compound of formula (VIII).

[0035]

[0036] Among them, R 1 , R 2 and R 3 Each is independently halogen; R 4 C 1-4 Alkyl; R 5 It is a halogen.

[0037] In some embodiments, the Hofmann alkylation reaction is carried out under the condition of an acid-binding agent, and the acid-binding agent is selected from any combination of triethylamine, N,N-diisopropylethylamine, N-methylmorpholine, pyridine, potassium carbonate or sodium carbonate;

[0038] In some embodiments, the Hofmann alkylation reaction solvent is selected from any combination of one or more of acetonitrile, ethanol, isopropanol, n-propanol, acetone, butanone, water, N,N-dimethylformamide or N,N-dimethylacetamide.

[0039] The present invention also provides a method for preparing a compound represented by formula (I) or a pharmaceutically acceptable salt thereof, comprising the following steps:

[0040]

[0041] Among them, R 1 , R 2 and R 3 Each is independently halogen; R 4 C 1-4 Alkyl; R 5 is a halogen;

[0042] (a) a compound of formula (VII) and a compound of formula (V) (III) undergo a Hofmann alkylation reaction to prepare a compound of formula (VI);

[0043] (b) ester hydrolysis of the compound of formula (VI) to obtain the compound of formula (V);

[0044] (c) the compound of formula (V) undergoes a rearrangement reaction to prepare a compound of formula (IV);

[0045] (d) subjecting the compound of formula (IV) to a reduction reaction to obtain a compound of formula (II);

[0046] (e) The compound of formula (II) undergoes an amide condensation reaction with the compound of formula (III) to prepare the compound of formula (I).

[0047] In some embodiments, the Hofmann alkylation reaction of step (a) is carried out under the condition of an acid-binding agent, and the acid-binding agent is selected from any combination of one or more of triethylamine, N,N-diisopropylethylamine, N-methylmorpholine, pyridine, potassium carbonate or sodium carbonate.

[0048] In some embodiments, the Hofmann alkylation reaction solvent in step (a) is selected from any combination of one or more of acetonitrile, ethanol, isopropanol, n-propanol, acetone, butanone, water, N,N-dimethylformamide or N,N-dimethylacetamide.

[0049] In some embodiments, the ester hydrolysis reaction of step (b) is carried out under alkaline conditions, and the base is selected from sodium hydroxide, potassium hydroxide or lithium hydroxide.

[0050] In some embodiments, the solvent for the ester hydrolysis reaction in step (b) is selected from any combination of one or more of methanol, ethanol, and tetrahydrofuran.

[0051] In some embodiments, the rearrangement reaction of step (c) is carried out in the presence of an azide reagent and an organic base, wherein the azide reagent is selected from sodium azide, trimethylsilyl azide (TMSA), diphenylphosphoryl azide (DPPA) or tetramethylguanidine azide (TMGA).

[0052] In some embodiments, the organic base of the rearrangement reaction of step (c) is selected from triethylamine, N,N-diisopropylethylamine or N-methylmorpholine;

[0053] In some embodiments, the solvent for the rearrangement reaction in step (c) is selected from any combination of one or more of toluene, xylene, 1,4-dioxane, 2-methyltetrahydrofuran, and ethylene glycol dimethyl ether.

[0054] In some embodiments, the reduction reaction of step (d) is carried out under the conditions of a catalyst and a reducing agent, and the catalyst is selected from palladium black, Pd / C, Pd(OH)2 / C, PdCl2 / C, Raney nickel or Pt / C.

[0055] In some embodiments, the reducing agent of step (d) is selected from one or more of hydrogen, formic acid, formamide, ammonium formate, hydrazine hydrate and cyclohexene.

[0056] In some embodiments, the reduction reaction solvent in step (d) is selected from any combination of one or more selected from methanol and ethanol.

[0057] In some embodiments, the amide condensation reaction of step (e) is carried out under the conditions of an organic base and a condensing agent, and the organic base is selected from any combination of one or more of triethylamine, N,N-diisopropylethylamine or N-methylmorpholine.

[0058] In some embodiments, the condensing agent of step (e) is selected from 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate, O-benzotriazole-tetramethyluronium hexafluorophosphate, 6-chlorobenzotriazole-1,1,3,3-tetramethyluronium hexafluorophosphate, benzotriazol-1-yl-oxytripyrrolidinophosphorus hexafluorophosphate or 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride.

[0059] In some embodiments, the solvent for the condensation reaction in step (e) is selected from any combination of one or more of N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone.

[0060] In some embodiments, wherein R 1 , R 2 , R 3 and R 5 Each is independently selected from F, Cl, Br or I; R 4 is selected from methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl or tert-butyl.

[0061] In some embodiments, R 1 F; R 2 F; R 3 Br; R 4 is ethyl; R 5 For Br.

[0062] In some embodiments, the compound of formula (I) is:

[0063]

[0064] The present invention also provides a compound of formula (II):

[0065]

[0066] R 1 , R 2 As defined in formula (I).

[0067] In some embodiments, the compound of formula (II) is selected from:

[0068]

[0069] On the other hand, the present invention also provides a crystalline form A of the compound of formula (I), characterized in that: the X-ray powder diffraction pattern of the crystalline form A has characteristic peaks at 2θ values ​​of 3.60, 17.90, and 19.33, and the 2θ error range is ±0.2°.

[0070] In some embodiments, the X-ray powder diffraction pattern of the crystalline form A has characteristic peaks at 2θ values ​​of 3.60, 8.56, 9.04, 16.76, 17.90, 19.33, 19.89, and 20.20, and the 2θ error range is ±0.2°.

[0071] In some embodiments, the X-ray powder diffraction pattern of the crystalline form A has characteristic peaks at 2θ values ​​of 3.60, 8.56, 9.04, 10.73, 16.24, 16.39, 16.76, 17.90, 19.33, 19.89, and 20.20, and the 2θ error range is ±0.2°.

[0072] In some embodiments, the X-ray powder diffraction pattern of the crystalline form A has characteristic peaks at 2θ values ​​of 3.60, 8.56, 9.04, 10.73, 15.72, 16.24, 16.39, 16.76, 17.14, 17.90, 18.41, 19.33, 19.89, 20.20, 21.37, and 22.43, and the 2θ error range is ±0.2°.

[0073] In some embodiments, the X-ray powder diffraction peak analysis data of Form A are shown in Table 1.

[0074] Table 1 XRPD diffraction peak analysis data of Form A

[0075]

[0076]

[0077] In some embodiments, the X-ray powder diffraction pattern of Form A is substantially as follows Figure 1 shown.

[0078] In some embodiments, the crystalline form A has a TGA-DSC spectrum with an endothermic peak at 202.10°C.

[0079] In some embodiments, the TGA-DSC spectrum of Form A is substantially as follows Figure 2 shown.

[0080] On the other hand, the present invention also provides a pharmaceutical composition comprising an effective therapeutic amount of the crystalline form A of the compound of formula (I) and one or more pharmaceutically acceptable carriers.

[0081] On the other hand, the present invention also provides the use of the crystalline form A of the compound of formula (I) or a pharmaceutical composition thereof in the preparation of a drug for treating a disease mediated by a KIF18A protease inhibitor.

[0082] The technical effect of the present invention is as follows: as the key intermediate compound of formula (II) of the compound of formula (I), the present application selects suitable starting materials and adopts bromide for reaction. The raw materials contain ester electron-withdrawing groups, which activate the ortho-bromine atoms of pyridine, making Hofmann alkylation easy to occur, and obtaining a product with a high yield; and the intermediate compound of formula (II) is prepared through subsequent reactions of ester hydrolysis, rearrangement reaction, and hydrogenation debromination, and the reaction selectivity is good, the conversion rate is high, the quality of the obtained product is more controllable, the yield is higher, and it is suitable for industrial production; the last step is conventional amide condensation, and there is no need to protect the hydroxyl group, and the atom economy is better.

[0083] Explanation and Definitions

[0084] Unless otherwise specified, the following terms and phrases used herein are intended to have the following meanings. A particular term or phrase should not be considered ambiguous or unclear without a special definition, but should be understood according to the ordinary meaning.

[0085] "Alkyl" refers to a straight or branched chain saturated hydrocarbon group. 1-4 Examples of the alkyl group include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl and the like.

[0086] "Halogen" means a fluorine, chlorine, bromine or iodine atom.

[0087] In the present invention, the amide reaction uses a condensing agent and an organic base, and the condensing agent includes but is not limited to carbodiimide condensing agents, carbonium salt condensing agents, phosphonium salt condensing agents, organic phosphorus condensing agents, and the like.

[0088] The carbodiimide condensing agent is selected from dicyclohexylcarbodiimide (DCC), diisopropylcarbodiimide (DIC) and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI);

[0089] When using a carbodiimide condensation agent, a catalyst or activator is generally required to be added, and the catalyst or activator is selected from 4-N,N-dimethylpyridine (DMAP), 1-hydroxybenzotriazole (HOBt), etc.;

[0090] The carbonium salt condensing agent includes, but is not limited to, 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU), O-benzotriazole-tetramethyluronium hexafluorophosphate (HBTU), 6-chlorobenzotriazole-1,1,3,3-tetramethyluronium hexafluorophosphate (HCTU), O-(7-azabenzotriazole-1-yl)-bis(tetrahydropyrrolyl)carbonium hexafluorophosphate (HAPyU), O-(benzotriazole-1-yl)-bis(tetrahydropyrrolyl)carbonium hexafluorophosphate (HBPyU), O-(benzotriazole-1-yl)-bis(dimethylamino)carbonium tetrafluoroborate (TBTU), O-(N-succinimidyl)-bis(dimethylamino)carbonium tetrafluoroborate (TSTU), etc.

[0091] Phosphonium salt condensing agents include, but are not limited to, benzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate (PyBOP), 7-azobenzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate (PyAOP), and benzotriazol-1-yloxy-tris(dimethylamino)phosphonium hexafluorophosphate (BOP).

[0092] The organophosphorus condensing agent includes, but is not limited to, diphenylphosphoryl chloride (DPP-Cl), diethyl cyanophosphate (DECP), diphenylphosphoryl azide (DPPA), dimethylthiophosphoryl azide (MPTA), bis(2-oxo-3-oxazolidinyl)phosphoryl chloride (BOP-Cl), and the like.

[0093] In the present invention, the acid-binding agent includes an organic base or an inorganic base, wherein the inorganic base includes but is not limited to potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, lithium hydroxide, calcium hydroxide, sodium bicarbonate, and the like.

[0094] In the present invention, the organic base includes but is not limited to triethylamine (TEA), N,N-diisopropylethylamine (DIPEA), N-methylmorpholine (NMM), pyridine (Py), ethylenediamine (EDA), monoethanolamine (MEA), 4-N,N-dimethylaminopyridine (DMAP), 1,8-diazabicycloundec-7-ene (DBU), potassium tert-butoxide, sodium tert-butoxide, n-butyl lithium, tert-butyl lithium, sodium bis(trimethylsilyl)amide (NaHMDS), lithium diisopropylamide (LDA), etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0095] Figure 1 is the XRPD spectrum of Form A of the compound of formula (I);

[0096] Figure 2 is the TGA-DSC spectrum of Form A of the compound of formula (I); DETAILED DESCRIPTION

[0097] The present invention is described in detail below by way of examples, but it is not intended to impose any adverse limitations on the present invention. The present invention has been described in detail herein, and specific embodiments thereof are also disclosed therein. It will be apparent to those skilled in the art that various changes and modifications may be made to the specific embodiments of the present invention without departing from the spirit and scope of the present invention.

[0098] Experimental equipment summary:

[0099] The structure of the compound of the present invention is determined by nuclear magnetic resonance (NMR) or / and liquid chromatography-mass spectrometry (LC-MS), or ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS). The NMR chemical shift (δ) is given in parts per million (ppm). The NMR is measured using a Bruker Neo 400M or Bruker Ascend 400 nuclear magnetic instrument, and the measurement solvent is deuterated dimethyl sulfoxide (DMSO-d6), deuterated methanol (CD3OD) and deuterated chloroform (CDCl3), heavy water (D2O), and the internal standard is tetramethylsilane (TMS).

[0100] Liquid chromatography-mass spectrometry (LC-MS) was performed using an Agilent 1260-6125B single quadrupole massspectrometer with a Welch Biomate column (C18, 2.7 μm, 4.6 × 50 mm) or a Waters H-Class SQD2 with a Welch Ultimate column (XB-C18, 1.8 μm, 2.1 × 50 mm) mass spectrometer (the ion source was electrospray ionization).

[0101] Ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS) was performed using a Waters UPLC H-class SQD mass spectrometer (with electrospray ionization as the ion source).

[0102] HPLC determination was performed using Waters e2695-2998 or Waters ARC and Agilent 1260 or Agilent Poroshell HPH high performance liquid chromatography.

[0103] The thin layer chromatography silica gel plate uses GF254 silica gel plate from Yantai Jiangyou Silica Gel Development Co., Ltd. or GF254 silica gel plate from Rushan Shangbang New Materials Co., Ltd. The specification used by TLC is 0.15mm~0.20mm, and the preparation type is 20×20cm. Column chromatography generally uses 200~300 mesh silica gel from Chenghua as the carrier.

[0104] Crystal characterization instruments and analysis methods:

[0105] X-ray powder diffraction (XRPD)

[0106] Solid samples were analyzed using an X-ray powder diffractometer (X'Pert PRO). An appropriate amount of fine powder of the sample was placed in the groove of the sample holder and pressed into a flat and dense surface with a glass sheet. The XRPD measurement parameters are shown in Table 2.

[0107] Table 2 XRPD test parameters

[0108] instrument PANalytical, X'Pert PRO light source Cu Target Scan Angle 3-45°(2θ) Scan speed 8° / min Light tube voltage / current 40KV / 40mA Diverging slits 1 / 8°

[0109] TGA-DSC analysis method:

[0110] The solid was analyzed by thermogravimetric-differential scanning calorimetry using a Mettler Toledo simultaneous thermal analyzer. An appropriate amount of the sample was placed in a crucible with a small spoon, spread evenly, and weighed. The sample was heated according to the parameters listed in Table 3, and the data was analyzed using STARe.

[0111] Table 3 TGA-DSC analysis method parameters

[0112]

[0113]

[0114] The starting materials in the examples of the present invention are known and can be purchased on the market, or can be synthesized by or according to methods known in the art.

[0115] Unless otherwise specified, all reactions of the present invention are carried out under continuous magnetic stirring in a dry nitrogen or argon atmosphere, the solvent is a dry solvent, and the reaction temperature is in degrees Celsius or ° C. Unless otherwise specified, room temperature refers to 25±5° C.

[0116] Example 1 Preparation of the compound of formula (I)

[0117]

[0118] Step 1: Preparation of compound (V)

[0119] Dissolve 1,4-dibromo-6,7-dihydro-5H-cyclopenta[c]pyridine-3-carboxylic acid ethyl ester (20 g, 57.3 mmol) and 4,4-difluoropiperidine (34.67 g, 286.5 mmol) in N-methylpyrrolidone (100 mL), add N,N-diisopropylethylamine (37.03 g, 286.5 mmol), and stir at 130°C to 150°C for 24 h. The reaction was cooled to room temperature, and water (1 L) and ethyl acetate (200 mL) were added for extraction. The aqueous phase was extracted twice with ethyl acetate (100 mL). The organic phases were combined, washed three times with saturated brine (20 mL), and concentrated. The reaction solution was concentrated and the crude product was purified by column chromatography (petroleum ether / ethyl acetate = 10 / 1) to give 4-bromo-1-(4,4-difluoropiperidin-1-yl)-6,7-dihydro-5H-cyclopenta[c]pyridine-3-carboxylic acid ethyl ester (19.8 g, yield 88.8%).

[0120] MS(ESI)M / Z: 389.18, 391.14[M+H] +

[0121] 1 H NMR (400MHz, CDCl3) δ = 4.42 (q, J = 7.1Hz, 2H), 3.59–3.50 (m, 4H), 3.02–2.91 (m, 4H), 2.16–1.98 (m, 6H), 1.41 (t, J = 7.1Hz, 3H).

[0122] Step 2: Preparation of compound (IV)

[0123] Dissolve 4-bromo-1-(4,4-difluoropiperidin-1-yl)-6,7-dihydro-5H-cyclopenta[c]pyridine-3-carboxylic acid ethyl ester (51 g, 131.1 mmol) in tetrahydrofuran (70 mL) and methanol (70 mL), add lithium hydroxide (9.44 g, 393.3 mmol, 70 mL water). Stir at room temperature for 6 h. Concentrate the solvent, adjust pH to 6 with 1N HCl solution, filter the precipitated solid, and dry to obtain 4-bromo-1-(4,4-difluoropiperidin-1-yl)-6,7-dihydro-5H-cyclopenta[c]pyridine-3-carboxylic acid (45.5 g, 95.8%).

[0124] MS (ESI) M / Z: 361.18, 363.19 [M+H] +

[0125] 1H NMR (400MHz, Methanol-d4) δ = 3.60–3.50 (m, 4H), 3.11–3.04 (m, 2H), 3.01–2.94 (m, 2H), 2.18–1.99 (m, 6H).

[0126] Step 3: Preparation of compound (III)

[0127] 4-Bromo-1-(4,4-difluoropiperidin-1-yl)-6,7-dihydro-5H-cyclopenta[c]pyridine-3-carboxylic acid (68.9 g, 190.86 mmol), diphenylphosphoryl azide (105 g, 381.72 mmol) were dissolved in toluene (100 mL), N,N-diisopropylethylamine (74 g, 572.58 mmol) and water (17.2 g, 954.3 mmol). The mixture was reacted at 90°C for 20 minutes. The solvent was concentrated, and water (100 mL) and ethyl acetate (200 mL) were added for extraction. The aqueous phase was extracted twice with ethyl acetate (100 mL). The organic phases were combined, washed three times with saturated brine (20 mL), and concentrated. The reaction solution was concentrated and the crude product was purified by column chromatography (petroleum ether / ethyl acetate = 5 / 1) to give 4-bromo-1-(4,4-difluoropiperidin-1-yl)-6,7-dihydro-5H-cyclopentadien[c]pyridine-3-amine (59.5 g, yield 93.9%).

[0128] MS (ESI) M / Z: 334.14 [M+H] +

[0129] 1 H NMR (400MHz, CDCl3) δ = 4.58 (s, 2H), 3.47 (t, J = 6.4Hz, 4H), 2.85 (dt, J = 19.6, 7.3Hz, 4H), 2.15–1.90 (m, 6H).

[0130] Step 4: Preparation of compound (II)

[0131] At room temperature, 4-bromo-1-(4,4-difluoropiperidin-1-yl)-6,7-dihydro-5H-cyclopentadien[c]pyridine-3-amine (66.3 g) was dissolved in methanol (100 mL), and 10% Pd / C (3.3 g) was added. The mixture was reacted under hydrogen for 18 hours. The mixture was filtered and the solvent was dried to obtain 1-(4,4-difluoropiperidin-1-yl)-6,7-dihydro-5H-cyclopentadien[c]pyridine-3-amine (48.52 g, yield 96%).

[0132] MS (ESI) M / Z: 254.24 [M+H] +

[0133] 1 H NMR (400MHz, DMSO-d6) δ = 5.95 (s, 1H), 5.35 (s, 2H), 3.41–3.33 (m, 4H), 2.72–2.56 (m, 4H), 2.04–1.86 (m, 6H).

[0134] Step 5: Preparation of compound (I)

[0135] 1-(4,4-difluoropiperidin-1-yl)-6,7-dihydro-5H-cyclopenta[c]pyridin-3-amine (48.52 g, 191.78 mmol), 4-((2-hydroxyethyl)sulfonamido)-2-(6-azaspiro[2.5]octan-6-yl)benzoic acid (74.76 g, 210.96 mmol) and 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (109.4 g, 287.67 mmol) were dissolved in N,N-dimethylacetamide (100 mL), and N,N-diisopropylethylamine (74.4 g, 575.34 mmol) was added. The reaction was allowed to react at room temperature for 18 hours. TLC monitored the reaction to be complete. The reaction solution was poured into water (5 L) and stirred for 1 h. The residue was filtered and slurried with water twice. The filter residue was slurried with ethyl acetate / methyl tert-butyl ether (1:1) to obtain a solid, namely N-(1-(4,4-difluoropiperidin-1-yl)-6,7-dihydro-5H-cyclopenta[c]pyridin-3-yl)-4-((2-hydroxyethyl)sulfonamido)-2-(6-azaspiro[2.5]octan-6-yl)benzamide (93.8 g, yield 83%).

[0136] MS (ESI) M / Z: 590.2 [M+H] +

[0137] 1 H NMR (400MHz, DMSO-d6) δ = 12.75 (s, 1H), 10.18 (s, 1H), 8.05 (d, J = 8.6Hz, 1H), 7.76 (s, 1H), 7.25 (d, J = 2.2Hz, 1H), 7.11 (dd, J = 8.6, 2.1Hz, 1H), 4.94(s,1H),3.81–3.71(m,2H),3.57–3.45(m,4H),3.39–3.33(m,2H), 3.05–2.88(m,4H),2.87–2.77(m,4H),2.29–1.35(m,10H),0.37(s,4H).

[0138] The compound of formula (I) in Example 1 was prepared through five steps of Hofmann alkylation reaction, ester hydrolysis, reduction, rearrangement reaction and condensation reaction, with a total yield of 63.6%. Compared with the method described in the patent for the compound, the yield was significantly improved.

[0139] The solid compound of formula (I) prepared in Example 1 was subjected to XRPD and TGA-DSC test characterization. The solid was Form A, and its XRPD spectrum was as follows: Figure 1 shown.

[0140] TGA-DSC spectrum Figure 2 As shown, the DSC results show that Form A has an endothermic peak at 202.10°C.

[0141] Intermediate (VI) can be prepared by referring to Advanced Synthesis & Catalysis (2016), 358 (12), 1916-1923:

[0142]

[0143] Compound (VI-1) (80 g, 0.87 mol) was dissolved in acetone (2 L), and silver nitrate (443 g, 2.61 mol) was added at 20°C, and then N-bromosuccinimide (NBS, 464 g, 2.61 mol) was slowly added. The reaction solution was stirred at room temperature overnight under nitrogen protection, and the raw material was completely consumed by TLC monitoring, and the filtrate was filtered and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (petroleum ether, PE) to obtain compound (VI-2) (150 g, yield 70%).

[0144] 1 H NMR (400MHz, CDCl3) δ = 2.33 (t, J = 7.0Hz, 4H), 1.73 (p, J = 7.0Hz, 2H).

[0145] At room temperature, ethyl cyanoformate (130.8 g, 1320.4 mmol) was dissolved in 1,2-dichloroethane (1.8 L), and (1,5-cyclooctadiene) (pentamethylcyclopentadiene) ruthenium chloride (12.58 g, 33.01 mmol) was added. 1,7-dibromoheptyl-1,6-diyne (compound (VI-2), 165 g, 660.2 mmol) was dissolved in 1,2-dichloroethane (600 mL), and it was slowly pumped into the 1,2-dichloroethane solution of ethyl cyanoformate over 3 hours using a syringe pump, during which the temperature of the reaction solution was kept at no more than 15°C. After the addition was completed, the reaction solution was stirred at room temperature for 16 hours. The reaction solution was concentrated, and the obtained solid was washed with ethyl acetate (1.3 L) and water (500 mL) three times. Then the organic phase was concentrated, and the obtained crude product was purified by column chromatography (petroleum ether / ethyl acetate = 10 / 1) to give compound (VI) 1,4-dibromo-6,7-dihydro-5H-cyclopenta[C]pyridine-3-carboxylic acid ethyl ester (179.3 g, yield 77.7%).

[0146] MS (ESI) M / Z: 350.1 [M+H] +

[0147] 1 H NMR (400MHz, CDCl3) δ = 4.45 (q, J = 7.1Hz, 1H), 3.10 (td, J = 7.8, 3.1Hz, 2H), 2.20 (dd, J = 15.5, 7.8Hz, 1H), 1.42 (t, J = 7.1Hz, 1H).

[0148] Intermediate (VIII) can be prepared according to the method of Journal of Medicinal Chemistry (2022), 65(6), 4972-4990

[0149]

[0150] At room temperature, methyl 2-fluoro-4-iodobenzoate (compound (VIII-1), 206 g, 735.6 mmol) was dissolved in dimethyl sulfoxide (1.3 L), followed by the addition of cesium carbonate (344.8 g, 1058.4 mmol) and 6-aza-spiro [2.5] octane hydrochloride (114 g, 772.38 mmol). After the addition was completed, the reaction solution was heated to 90 ° C and stirred overnight. After cooling to room temperature, water (3 L) and ethyl acetate (2 L) were added, and the aqueous phase was extracted twice with ethyl acetate (2 L). The organic phases were combined, saturated brine (1 L) was added and washed three times, and the reaction solution was concentrated. The crude product was purified by column chromatography to obtain compound (VIII-2) methyl 4-iodo-2-(6-azaspiro [2.5] octan-6-yl) benzoate (240.3 g, yield 88%).

[0151] MS (ESI) M / Z: 372.19 [M+H] +

[0152] 1 H NMR (400MHz, CDCl3) δ = 7.39 (d, J = 8.2Hz, 1H), 7.37 (d, J = 1.6Hz, 1H), 7.29–7 .25(m,1H),3.88(s,3H),3.10–3.02(m,4H),1.57–1.47(m,4H),0.34(s,4H)

[0153] At room temperature, methyl 4-iodo-2-(6-azaspiro[2.5]octan-6-yl)benzoate (240 g, 646.5 mmol) was dissolved in N,N-dimethylformamide (1200 mL), followed by the addition of 2-hydroxy-1-sulfonamide (121 g, 969.8 mmol), potassium phosphate (685 g, 3232.5 mmol), cuprous iodide (61.5 g, 323.25 mmol), and sarcosine (28.8 g, 323.25 mmol). After the addition was completed, the reaction system was replaced with a nitrogen atmosphere, the reaction solution was heated to 100° C., and stirred overnight. The mixture was cooled to room temperature, and water (3 L) and ethyl acetate (3 L) were added. The aqueous phase was extracted twice with ethyl acetate (2 L). The organic phases were combined and washed three times with saturated brine (2 L). The organic phase was concentrated and the crude product was purified by column chromatography to give compound (VIII-3) 4-((2-hydroxyethyl)sulfonamido)-2-(6-azaspiro[2.5]octan-6-yl)benzoic acid methyl ester (178.4 g, yield 75%).

[0154] MS (ESI) M / Z: 369.4 [M+H] +

[0155] 1H NMR (400MHz, CDCl3) δ = 7.72 (d, J = 8.4Hz, 1H), 6.96 (s, 1H), 6.77 (d, J = 7.3Hz, 1H), 4.11–4.02 (m, 2 H),3.90(d,J=11.0Hz,3H),3.37–3.26(m,2H),3.17–3.03(m,4H),1.61–1.48(m,4H),0.35(s,4H)

[0156] At room temperature, methyl 4-((2-hydroxyethyl)sulfonamido)-2-(6-azaspiro[2.5]oct-6-yl)benzoate (178 g, 484 mmol) was dissolved in tetrahydrofuran (500 mL) and methanol (500 mL), followed by the addition of an aqueous solution (500 mL) of sodium hydroxide (90 g, 2250 mmol). After the addition was complete, the reaction solution was heated to 60°C and stirred for 2 hours. After cooling to room temperature, the reaction solution was concentrated, and water (500 mL) and ethyl acetate (1 L) were added for extraction. The resulting aqueous phase was cooled to 0°C, and concentrated hydrochloric acid was slowly added dropwise to adjust the pH to 5-6. A large amount of white solid precipitated, which was filtered and dried to obtain compound (VIII) 4-((2-hydroxyethyl)sulfonamido)-2-(6-azaspiro[2.5]oct-6-yl)benzoic acid (161 g, yield 94%).

[0157] MS (ESI) M / Z: 355.3 [M+H] +

[0158] 1 H NMR (400MHz, DMSO-d6) δ = 7.94 (d, J = 8.6Hz, 1H), 7.35 (d, J = 2.1Hz, 1H), 7.16 (dd, J = 8.6, 2.1Hz, 1H), 3.75(t,J=6.4Hz,2H),3.34(t,J=6.4Hz,3H),3.00(t,J=5.3Hz,4H),1.64–1.50(m,4H),0.43(s,4H).

[0159] Comparative Example 1 Preparation method of compound of formula (I)

[0160] Laboratory method, step B has poor selectivity because both Cl in the reaction substrate 1b can participate in the reaction, and needs to be reacted with the aid of a microwave reactor, resulting in a high content of isomer impurities (producing by-products 1d and 1e), step C has a low yield (45%), step D has a yield of 56%, and the total yield of the compound of formula (I) is only 4.2%, which is not suitable for industrial production.

[0161]

[0162] Steps:

[0163] Step A: At room temperature, 3,5,6-trichloro-1,2,4-triazine (800 mg, 0.138 mmol) was dissolved in cyclopentene (4 mL), and the reaction solution was stirred at 70°C for 48 hours. The mixture was cooled to room temperature and concentrated under reduced pressure. The crude target compound was purified by silica gel column chromatography to obtain the product 1,3-dichloro-6,7-dihydro-5H-cyclopenta[c]pyridine (700 mg).

[0164] MS (ESI) M / Z: 188.0 [M+H] + .

[0165] Step B: At room temperature, 3-dichloro-6,7-dihydro-5H-cyclopenta[c]pyridine (400 mg, 2.126 mmol) and 4,4-difluoropiperidine (283 mg, 2.339 mmol) were added to N-methylpyrrolidone (5 mL), and the reaction was stirred at 150°C in a microwave for 8 hours. After cooling to room temperature, the reaction solution was added to water (50 mL), extracted with ethyl acetate (40 mL), the organic phase was washed three times with water (20 mL / time), and then washed with a saturated sodium chloride aqueous solution (40 mL), the organic phase was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by silica gel column chromatography to obtain the product 3-chloro-1-(4,4-difluoropiperidin-1-yl)-6,7-dihydro-5H-cyclopenta[c]pyridine (410 mg), i.e., compound 1c.

[0166] MS (ESI) M / Z: 273.0 [M+H] + .

[0167] Step C: Under nitrogen protection at room temperature, 3-chloro-1-(4,4-difluoropiperidin-1-yl)-6,7-dihydro-5H-cyclopenta[c]pyridine (490 mg, 1.797 mmol) was dissolved in dioxane (5 mL), and 2,4-dimethoxybenzylamine (601 mg, 3.594 mmol), tris(dibenzylideneacetone)palladium (165 mg, 0.18 mmol), 4,5-bis(diphenylphosphine)-9,9-dimethylxanthene (208 mg, 0.36 mmol) and cesium carbonate (1.75 g, 5.391 mmol) were added to the system. The reaction solution was stirred at 100°C in a microwave for 8 hours. The reaction mixture was filtered and concentrated under reduced pressure. The crude compound was purified by preparative HPLC to give the product 1-(4,4-difluoropiperidin-1-yl)-N-(2,4-dimethoxybenzyl)-6,7-dihydro-5H-cyclopenta[c]pyridin-3-amine (330 mg).

[0168] MS (ESI) M / Z: 404.2 [M+H] + .

[0169] Step D: At room temperature, 1-(4,4-difluoropiperidin-1-yl)-N-(2,4-dimethoxybenzyl)-6,7-dihydro-5H-cyclopenta[c]pyridine-3-amine (330 mg, 0.818 mmol) and trifluoroacetic acid (2 mL) were added to dichloromethane (5 mL) and stirred for 2 hours. The mixture was concentrated under reduced pressure and the crude compound was purified by preparative high performance liquid chromatography to obtain the product 1-(4,4-difluoropiperidin-1-yl)-6,7-dihydro-5H-cyclopenta[c]pyridine-3-amine (118 mg).

[0170] MS (ESI) M / Z: 254.1 [M+H] + .

[0171] Step E: At room temperature, 4-iodo-2-(6-azaspiro[2.5]octan-6-yl)benzoic acid (93 mg, 0.26 mmol), 1-(4,4-difluoropiperidin-1-yl)-6,7-dihydro-5H-cyclopenta[c]pyridine-3-amine (66 mg, 0.26 mmol), HATU (198 mg, 0.52 mmol) and N,N-diisopropylethylamine (101 mg, 0.78 mmol) were added to N,N-dimethylformamide (3 mL) and stirred at room temperature overnight. The reaction solution was added to water and extracted with ethyl acetate (20 mL). The organic phase was washed three times with water (20 mL) and then with a saturated sodium chloride aqueous solution (25 mL). The organic phase was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The concentrate was purified by silica gel column chromatography. The crude compound obtained was purified by preparative high performance liquid chromatography to obtain the product N-(1-(4,4-difluoropiperidin-1-yl)-6,7-dihydro-5H-cyclopenta[c]pyridin-3-yl)-4-iodo-2-(6-azaspiro[2.5]octan-6-yl)benzamide (94 mg). MS (ESI) M / Z: 593.2 [M+H] + .

[0172] Step F: Under nitrogen protection at room temperature, N-(1-(4,4-difluoropiperidin-1-yl)-6,7-dihydro-5H-cyclopenta[c]pyridin-3-yl)-4-iodo-2-(6-azaspiro[2.5]octan-6-yl)benzamide (60 mg, 0.101 mmol) was dissolved in N,N-dimethylformamide (3 mL), and 2-hydroxyethane-1-sulfonamide (25.3 mg, 0.202 mmol), sarcosine (4.5 mg, 0.05 mmol), cuprous iodide (38.5 mg, 0.202 mmol) and potassium phosphate (107 mg, 0.505 mmol) were added to the system. The resulting reaction solution was stirred at 130° C. for 16 hours. The temperature was cooled to room temperature, the reaction solution was added to water (10 mL), extracted with ethyl acetate (15 mL), the organic phase was washed three times with water (15 mL / time), and then washed with saturated sodium chloride aqueous solution, the organic phase was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude compound was purified by preparative high performance liquid chromatography to give the target product N-(1-(4,4-difluoropiperidin-1-yl)-6,7-dihydro-5H-cyclopenta[c]pyridin-3-yl)-4-((2-hydroxyethyl)sulfonamido)-2-(6-azaspiro[2.5]octan-6-yl)benzamide (24.27 mg).

[0173] MS (ESI) M / Z: 590.4 [M+H] + .

[0174] 1H NMR (400MHz, DMSO) δ12.75(s,1H),10.17(s,1H),8.04(d,J=8.0Hz,1H),7.76(s,1H),7.24(s,1H),7.10(d,J=8.0Hz,1H),4.95(s,1H),3.75(t, J=8.0Hz,2H),3.45-3.55(m,4H),3.39-3.30(m,4H),3.01-2.90(m,4H) ,2.84–2.80(m,4H),2.12–2.00(m,6H),1.75-1.71(m,2H),0.37(s,4H).

[0175] Biological test example 1: Evaluation of the inhibitory effect of the compounds of the present invention on human KIF18A actin activity

[0176] This experiment used the ADP-Glo ​​method to test the inhibitory effect of the compound of formula (I) on human KIF18A actin, and obtained the half concentration IC of the compound to inhibit protein activity. 50 .

[0177] The abbreviations and their corresponding names used in the test examples of the present invention are as follows:

[0178] abbreviation name <![CDATA[MgCl2]]> Magnesium chloride KCl Potassium chloride EGTA Ethylene glycol bis(2-aminoethyl ether)tetraacetic acid DTT Dithiothreitol BSA BSA Tween-20 Polysorbate 20 CP Smart Chemistry R1 <![CDATA[ADP-Glo TM Reagent]]> R2 Kinase Detection Substrate

[0179] 1. Experimental Materials

[0180] 1) MgCl2, KCl, EGTA, DTT, BSA, and Tween-20 were purchased from Sigma to prepare Assay buffer

[0181] 2) KIF18A was purchased from CP

[0182] 3) MT was purchased from Cytoskeleton

[0183] 4) Paclitaxel was purchased from MCE

[0184] 5) ADP-Glo ​​reagent, purchased from Promega.

[0185] 2. Experimental Methods

[0186] a) Add 50 nL of the test compound or DMSO to a 384-well microplate;

[0187] b) Add 2.5 μL of KIF18A diluted in Assay buffer and incubate at room temperature for 30 minutes;

[0188] c) Add 2.5 μL of substrate mixture diluted in Assay buffer and incubate at room temperature for 60 minutes;

[0189] d) Add 5 μL ADP-Glo ​​R1, centrifuge briefly, and incubate at room temperature for 2 hours;

[0190] e) Add 10 μL ADP-Glo ​​R2, centrifuge briefly, and incubate at room temperature for 1 hour;

[0191] f) Chemiluminescent signals were detected using Envision microplate reader (PerkinElmer).

[0192] g) GraphPad Prism 6 software was used for data analysis to obtain the IC of the compound. 50 .

[0193] 3. Experimental results

[0194] The results of the inhibition of human KIF18A protein activity by the compound of formula (I): IC 50 is 125nM.

[0195] Biological test example 2: Evaluation of the inhibitory effect of the compound of the present invention on the proliferation of ovarian cancer cell NCIOVCAR3

[0196] In this experiment, the CellTiter-Glo (CTG) method was used to test the inhibitory effect of the compound of formula (I) on the proliferation of NCIOVCAR3 cells, and the half-maximum concentration IC of the compound for inhibiting cell growth was obtained. 50 .

[0197] 1. Experimental Materials

[0198] a) 1640 culture medium, fetal bovine serum (FBS), and Penicillin-Streptomycin were purchased from GIBCO

[0199] b) CellTiter-Glo reagent, purchased from Promega.

[0200] 2. Experimental Methods

[0201] a) Day 0: NCIOVCAR3 cells were seeded in a 384-well plate at a density of 500 cells per well, with 50 μL per well.

[0202] b) Day 1: Add the test compound to the culture plate using TECAN, with a final DMSO concentration of 0.5%, and add DMSO to the blank control wells, with a final concentration of 0.5%. Place the culture plate in a cell culture incubator and incubate for 120 hours (37° C., 5% CO 2 ).

[0203] c) Day 6: Add 50 μL Cell Titer-Glo reagent to each well, shake at 500 rpm for 2 minutes, and incubate at room temperature in the dark for 10 minutes to stabilize the luminescent signal.

[0204] d) Chemiluminescent signals were detected using Envision microplate reader (PerkinElmer).

[0205] e) GraphPad Prism 6 software was used for data analysis to obtain the IC of the compound. 50 .

[0206] 3. Experimental results

[0207] The results of the inhibition of proliferation of ovarian cancer cell NCIOVCAR3 by the compound of formula (I): IC 50 is 31nM.

Claims

1. A method for preparing a compound represented by formula (I) or a pharmaceutically acceptable salt thereof, characterized in that: Prepared by condensation reaction of a compound of formula (II) with a compound of formula (III); Among them, R 1 , R 2 Each is independently halogen.

2. The method according to claim 1, wherein the condensation reaction is carried out under the conditions of an organic base and a condensing agent, and the organic base is selected from one or more of triethylamine, N,N-diisopropylethylamine or N-methylmorpholine in any combination; The condensing agent is selected from 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate, O-benzotriazole-tetramethyluronium hexafluorophosphate, 6-chlorobenzotriazole-1,1,3,3-tetramethyluronium hexafluorophosphate, benzotriazole-1-yl-oxytripyrrolidinophosphine hexafluorophosphate or 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride; The solvent for the condensation reaction is selected from any combination of one or more of N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone.

3. The method according to claim 1 or 2, wherein the compound of formula (II) is prepared by reduction reaction of a compound of formula (IV), in, R 1 , R 2 and R 3 Each is independently halogen.

4. The method according to claim 3, wherein the reduction reaction is carried out under the conditions of a catalyst and a reducing agent, and the catalyst is selected from palladium black, Pd / C, Pd(OH)2 / C, PdCl2 / C, Raney nickel or Pt / C; The reducing agent is selected from one or more of hydrogen, formic acid, formamide, ammonium formate, hydrazine hydrate and cyclohexene; The solvent for the reduction reaction is selected from any combination of one or more of methanol and ethanol.

5. The method according to any one of claims 1 to 4, wherein the compound of formula (IV) is prepared by rearrangement reaction of the compound of formula (V), in, R 1 , R 2 and R 3 Each is independently halogen.

6. The method according to claim 5, wherein the rearrangement reaction is carried out in the presence of an azide reagent and an organic base, wherein the azide reagent is selected from sodium azide, trimethylsilyl azide (TMSA), diphenylphosphoryl azide (DPPA) or tetramethylguanidine azide (TMGA); The organic base is selected from triethylamine, N,N-diisopropylethylamine or N-methylmorpholine; The solvent for the rearrangement reaction is selected from one or more of toluene, xylene, 1,4-dioxane, 2-methyltetrahydrofuran, and ethylene glycol dimethyl ether in any combination.

7. The method according to any one of claims 1 to 6, wherein the compound of formula (V) is prepared by ester hydrolysis of the compound of formula (VI), in, R 1 , R 2 and R 3 Each is independently halogen; R 4 C 1-4 alkyl.

8. The method according to claim 7, wherein the ester hydrolysis reaction is carried out under alkaline conditions, and the base is selected from sodium hydroxide, potassium hydroxide or lithium hydroxide; The solvent is selected from any combination of methanol, ethanol and tetrahydrofuran.

9. The method according to any one of claims 1 to 8, wherein the compound of formula (VI) is prepared by Hofmann alkylation reaction of a compound of formula (VII) with a compound of formula (VIII), in, R 1 , R 2 and R 3 Each is independently halogen; R 4 C 1-4 Alkyl; R 5 It is a halogen.

10. The method according to claim 9, wherein the Hofmann alkylation reaction is carried out under the condition of an acid-binding agent, and the acid-binding agent is selected from one or more of triethylamine, N,N-diisopropylethylamine, N-methylmorpholine, pyridine, potassium carbonate or sodium carbonate in any combination; The solvent for the alkylation reaction is selected from one or more of acetonitrile, ethanol, isopropanol, n-propanol, acetone, butanone, water, N,N-dimethylformamide or N,N-dimethylacetamide.

11. A method for preparing a compound represented by formula (I) or a pharmaceutically acceptable salt thereof, comprising the following steps: in, R 1 , R 2 and R 3 Each is independently halogen; R 4 C 1-4 Alkyl; R 5 is a halogen; (a) a compound of formula (VII) and a compound of formula (V) (III) undergo a Hofmann alkylation reaction to prepare a compound of formula (VI); (b) ester hydrolysis of the compound of formula (VI) to obtain the compound of formula (V); (c) the compound of formula (V) undergoes a rearrangement reaction to prepare a compound of formula (IV); (d) subjecting the compound of formula (IV) to a reduction reaction to obtain a compound of formula (II); (e) The compound of formula (II) undergoes an amide condensation reaction with the compound of formula (III) to prepare the compound of formula (I).

12. The method according to any one of claims 1 to 11, wherein: R 1 , R 2 , R 3 and R 5 Each is independently selected from F, Cl, Br or I; R 4 is selected from methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl or tert-butyl; Preferably, R 1 F; R 2 F; R 3 Br; R 4 is ethyl; R 5 For Br.

13. The method according to any one of claims 1 to 12, wherein: The compound of formula (I) is:

14. Compounds of formula (II): R 1 , R 2 The definition as in claim 1.

15. Form A of the compound of formula (I), characterized in that: The X-ray powder diffraction spectrum of the crystal form A has characteristic peaks at 2θ values ​​of 3.60, 17.90, and 19.33, and the 2θ error range is ±0.2°; Preferably, the X-ray powder diffraction pattern of the crystalline form A has characteristic peaks at 2θ values ​​of 3.60, 8.56, 9.04, 16.76, 17.90, 19.33, 19.89, and 20.20, and the 2θ error range is ±0.2°; Preferably, the X-ray powder diffraction pattern of the crystalline form A has characteristic peaks at 2θ values ​​of 3.60, 8.56, 9.04, 10.73, 16.24, 16.39, 16.76, 17.90, 19.33, 19.89, and 20.20, and the 2θ error range is ±0.2°; Preferably, the X-ray powder diffraction pattern of the crystalline form A has characteristic peaks at 2θ values ​​of 3.60, 8.56, 9.04, 10.73, 15.72, 16.24, 16.39, 16.76, 17.14, 17.90, 18.41, 19.33, 19.89, 20.20, 21.37, and 22.43, and the 2θ error range is ±0.2°; Further preferably, the X-ray powder diffraction pattern of the crystalline form A is substantially as shown in Figure 1.

16. The crystal form A according to claim 15, wherein its TGA-DSC spectrum has an endothermic peak at 202.10°C; preferably, the TGA-DSC spectrum of the crystal form A is substantially as shown in FIG2.

17. A pharmaceutical composition comprising a therapeutically effective amount of the crystalline form A according to claim 15 or 16 and one or more pharmaceutically acceptable carriers.

18. Use of the crystalline form A according to claim 15 or 16 or the pharmaceutical composition according to claim 17 in the preparation of a drug for treating a disease mediated by a KIF18A protease inhibitor.

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