Inhibitors of factor xa and methods of making and using the same

Abstract

The application belongs to the technical field of medicine and chemical industry, and particularly relates to FXa inhibitors and a preparation method and application thereof. The FXa inhibitor has a structural general formula as shown in the description, wherein R1 is,,, or. The preparation method of the FXa inhibitor comprises the following steps: taking p-nitroaniline as a starting material, and sequentially performing amide condensation, substitution and cycloaddition to prepare a compound 5; taking p-methoxyaniline as a starting material, and performing diazotization, cyclization, elimination and nitro reduction to prepare a compound 10; performing reaction of the compound 10 and 2,5-dimethoxytetrahydrofuran to obtain a compound 11, performing a Mannich reaction to obtain intermediates 12a-12e, and finally performing ammonolysis to obtain compounds A01-A05. The FXa inhibitor and the preparation method thereof synthesize novel pyrazolopyridine derivatives. When the FXa inhibitor is applied to preparation of an antithrombotic drug, high-efficiency anticoagulation activity, good pharmacokinetic properties and a low risk of bleeding are obtained.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical and chemical technology, specifically relating to FXa inhibitors, their preparation methods, and uses. Background Technology

[0002] Factor Xa (FXa) is a core serine protease in the coagulation cascade, located at the intersection of intrinsic and extrinsic coagulation pathways. It catalyzes the conversion of prothrombin to thrombin, playing a crucial role in thrombus formation. Because FXa is a key node in the coagulation amplification cascade, theoretically, inhibiting even a small amount of FXa can significantly reduce thrombin production, thereby achieving effective anticoagulation and potentially reducing the impact on normal hemostasis. Therefore, FXa is considered one of the most valuable targets in current anticoagulant drug development.

[0003] In recent years, direct FXa inhibitors, represented by rivaroxaban, apixaban, and edoxaban, have been successively launched on the market, demonstrating good clinical efficacy in the prevention and treatment of thrombotic diseases. These drugs have advantages such as high oral activity, a clear mechanism of action, and no need for frequent monitoring of coagulation parameters. Among them, apixaban (chemical name: 1-(4-methoxyphenyl)-7-oxo-6-[4-(2-oxopiperidin-1-yl)phenyl]-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide) is a highly effective and selective FXa inhibitor, widely used clinically for the prevention of venous thromboembolism after hip or knee replacement surgery and for the prevention of stroke in patients with atrial fibrillation.

[0004] Currently, numerous synthetic methods for apixaban and its analogues have been reported. For example, Chinese patent CN105732622A discloses a method for preparing apixaban from p-nitroaniline and δ-valerolactone as starting materials through a multi-step reaction. Although the starting materials are inexpensive and readily available, the route repeatedly uses sensitive reagents such as trimethylaluminum (AlMe3), requiring high control of reaction conditions and involving cumbersome steps, thus the overall yield needs further improvement. Chinese patent CN102675314A discloses a method for synthesizing apixaban by cyclizing p-nitroaniline with 5-bromopentanoyl chloride, followed by chlorination, elimination, [3+2] cyclization, reduction, amidation cyclization, and ammonolysis. This route also suffers from problems such as a long procedure time, high equipment requirements for some reactions (such as catalytic hydrogenation), and the use of expensive 5-bromopentanoyl chloride.

[0005] Furthermore, existing FXa inhibitors still present challenges in clinical application, including bleeding risks, individual tolerability differences, and long-term safety concerns. For example, although apixaban carries a lower bleeding risk than warfarin, adverse reactions such as gastrointestinal bleeding cannot be ignored. Therefore, developing novel FXa inhibitors with higher activity and better safety profiles, while exploring more efficient and economical synthesis methods, remains of significant clinical value and practical importance. Summary of the Invention

[0006] The technical problem to be solved by this invention is to overcome the above-mentioned defects in the prior art and provide an FXa inhibitor and its preparation method. A series of novel pyrrole groups containing different amino side chains were successfully introduced onto the benzene ring of the apixaban core, and a series of novel pyrazolopyridine derivatives were designed and synthesized. When applied to the preparation of antithrombotic drugs, these derivatives exhibit high anticoagulant activity, good pharmacokinetic properties, and a low bleeding risk.

[0007] The FXa inhibitor described in this invention has the following general structural formula: , where R1 is , , , or .

[0008] The compound A01, an inhibitor of FXa, is The chemical name is 6-(4-(2-((dimethylamino)methyl)-1H-pyrrolo-1-yl)phenyl)-1-(4-methoxyphenyl)-7-oxo-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide; A02 is The chemical name is 6-(4-(2-((diethylamino)methyl)-1H-pyrrolo-1-yl)phenyl)-1-(4-methoxyphenyl)-7-oxo-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide; A03 is The chemical name is 1-(4-methoxyphenyl)-7-oxo-6-(4-(2-(pyrrolidine-1-ylmethyl)-1H-pyrrol-1-yl)phenyl)-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide; A04 is The chemical name is 1-(4-methoxyphenyl)-7-oxo-6-(4-(2-(piperidin-1-ylmethyl)-1H-pyrrolo-1-yl)phenyl)-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide; A05 is Its chemical name is 1-(4-methoxyphenyl)-6-(4-(2-(morpholinomethyl)-1H-pyrrolo-1-yl)phenyl)-7-oxo-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide.

[0009] The method for preparing the FXa inhibitor includes the following steps: (1) Starting with p-nitroaniline, it undergoes an amide condensation reaction with 5-chloropentanoyl chloride to generate compound 5-chloro-N-(4-nitrophenyl)pentanoamide, i.e., compound 2. Compound 2 undergoes an intramolecular nucleophilic substitution cyclization reaction under alkaline conditions to generate compound 1-(4-nitrophenyl)piperidin-2-one, i.e., compound 3. Compound 3 undergoes a carbonyl α-position chlorination reaction under strong chlorination conditions to generate compound 3,3-dichloro-1-(4-nitrophenyl)piperidin-2-one, i.e., compound 4. Compound 4 undergoes a nucleophilic substitution-elimination tandem reaction with morpholine to obtain compound 3-morpholino-1-(4-nitrophenyl)-5,6-dihydropyridine-2(1H)-one, i.e., compound 5. (2) Using p-methoxyaniline as the starting material, sodium nitrite and hydrochloric acid were added to react and generate a diazonium salt. Then, ethyl 2-chloroacetoacetate was added to carry out a coupling reaction to obtain compound (Z)-2-chloro-2-(2-(4-methoxyphenyl)hydrazyl)ethyl acetate, i.e., compound 7; (3) Compound 5 and Compound 7 were mixed and subjected to a cycloaddition reaction to obtain compound 1-(4-methoxyphenyl)-7a-morpholino-6-(4-nitrophenyl)-7-oxo-3a,4,5,6,7,7a-hexahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ethyl ester, namely compound 8; (4) Compound 8 is mixed with a strong acid and undergoes an acid-catalyzed elimination reaction to generate compound 1-(4-methoxyphenyl)-6-(4-nitrophenyl)-7-oxo-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ethyl ester, i.e., compound 9; iron powder is mixed with ammonium chloride and acid is added, and compound 9 is added in batches to generate compound 6-(4-aminophenyl)-1-(4-methoxyphenyl)-7-oxo-4, 5,6,7-Tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ethyl ester, namely compound 10, was reacted with p-toluenesulfonic acid and 2,5-dimethoxytetrahydrofuran to prepare compound 6-(4-(1H-pyrrolo-1-yl)phenyl)-1-(4-methoxyphenyl)-7-oxo-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ethyl ester, namely compound 11; (5) Add compound 11, amine source, and formaldehyde solution to acetic acid and react at room temperature to generate Mannich bases, namely compound 12a, compound 12b, compound 12c, compound 12d, and compound 12e. (6) The compound Mannich base, sodium methoxide and formamide are mixed and dissolved in a solvent to carry out an amidation reaction to obtain FXa inhibitors, namely target compounds A01, A02, A03, A04 and A05.

[0010] The specific steps for generating compound 5-chloro-N-(4-nitrophenyl)pentanamide (compound 2) in step (1) are as follows: at room temperature, p-nitroaniline (compound 1) and triethylamine are dissolved in tetrahydrofuran, and 5-chloropentanyl chloride is added dropwise at 0~5℃. After the addition is complete, the reaction is stirred at room temperature. After the reaction is completed, the reaction solution is poured into ice water to precipitate. The precipitate is filtered, washed, and dried under reduced pressure to obtain compound 5-chloro-N-(4-nitrophenyl)pentanamide (compound 2).

[0011] The specific steps for generating compound 1-(4-nitrophenyl)piperidin-2-one (compound 3) in step (1) are as follows: compound 5-chloro-N-(4-nitrophenyl)pentanamide (compound 2) and potassium carbonate are added to dimethyl sulfoxide and stirred at 75~85℃. After the reaction is completed, the mixture is cooled to room temperature, the reaction solution is poured into ice water, a precipitate is precipitated, filtered, the precipitate is washed and dried under reduced pressure to obtain compound 1-(4-nitrophenyl)piperidin-2-one (compound 3).

[0012] The specific steps for generating compound 3,3-dichloro-1-(4-nitrophenyl)piperidin-2-one (compound 4) in step (1) are as follows: compound 1-(4-nitrophenyl)piperidin-2-one (compound 3) is dissolved in dichloromethane, and phosphorus pentachloride is added after stirring and dissolving. The mixture is heated under reflux and reacted. After the reaction is completed, the mixture is cooled to room temperature, the reaction solution is poured into ice water, the aqueous layer is separated, and the solution is extracted with dichloromethane. The organic phase is washed, dried, filtered, distilled under reduced pressure, and ground to obtain compound 3,3-dichloro-1-(4-nitrophenyl)piperidin-2-one (compound 4).

[0013] The specific steps for generating compound 3-morpholino-1-(4-nitrophenyl)-5,6-dihydropyridine-2(1H)-one (compound 5) in step (1) are as follows: 3,3-dichloro-1-(4-nitrophenyl)piperidin-2-one (compound 4) is mixed with morpholine and stirred at 25~135℃. After the reaction is completed, the mixture is cooled to room temperature and distilled under reduced pressure. The resulting precipitate is filtered and washed to obtain compound 3-morpholino-1-(4-nitrophenyl)-5,6-dihydropyridine-2(1H)-one (compound 5).

[0014] The specific steps of step (2) are as follows: under room temperature conditions, hydrochloric acid is added to the aqueous solution of p-methoxyaniline and stirred. After the addition is completed, sodium nitrite aqueous solution is added dropwise at -5~0℃. After the addition is completed, the reaction system is stirred at -5~0℃. Then, ethyl 2-chloroacetoacetate and sodium acetate are added and stirred. Then the reaction system is heated to 20~30℃ and reacted. After the reaction is completed, a precipitate is precipitated, filtered, and the precipitate is washed and dried under reduced pressure to obtain compound (Z)-2-chloro-2-(2-(4-methoxyphenyl)hydrazyl)ethyl acetate.

[0015] The specific steps of step (3) are as follows: triethylamine and ethyl acetate of compound (Z)-2-chloro-2-(2-(4-methoxyphenyl)hydrazino) are added to an ethyl acetate solution of compound 3-morpholino-1-(4-nitrophenyl)-5,6-dihydropyridine-2(1H)-one. The reaction is stirred at 75~85℃. After the reaction is completed, the mixture is cooled to room temperature, and a precipitate is formed. The precipitate is filtered and washed to obtain ethyl 1-(4-methoxyphenyl)-7a-morpholino-6-(4-nitrophenyl)-7-oxo-3a,4,5,6,7,7a-hexahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid.

[0016] The specific steps for synthesizing compound 9 in step (4) are as follows: Trifluoroacetic acid is added dropwise to the dichloromethane solution of compound 8 under ice bath conditions. After the addition is complete, the reaction is stirred at room temperature. After the reaction is complete, the reaction solution is poured into ice water, the organic phase is separated, and washed successively with water and saturated brine. The organic phase is dried with anhydrous sodium sulfate, filtered, and the solvent is removed by vacuum distillation to obtain a reddish-brown solid. The solid is then ground with diethyl ether to obtain a yellow intermediate, namely compound 9.

[0017] The specific steps for synthesizing compound 10 in step (4) are as follows: iron powder, hydrochloric acid and ammonium chloride are added to an ethanol solution and stirred vigorously at 75~85℃. Then, compound 9 is added in batches and the reaction continues until the reaction is completed by TLC monitoring. The hot reaction solution is filtered while hot and washed with hot methanol. The filtrates are combined and the solvent is removed by vacuum evaporation to obtain the target compound 10.

[0018] The specific steps for synthesizing compound 11 in step (4) are as follows: compound 10 and p-toluenesulfonic acid are added to a tetrahydrofuran solution of 2,5-dimethoxytetrahydrofuran. The mixture is heated to 55~65℃ for reaction. After the reaction is completed, it is cooled to room temperature. The reaction solution is extracted with dichloromethane, the organic phase is washed with water, and dried under reduced pressure to obtain a yellow intermediate, namely compound 11.

[0019] The amine source in step (5) is dimethylamine hydrochloride, diethylamine hydrochloride, tetrahydropyrrole, piperidine, or morpholine.

[0020] The specific steps of compound 12a in step (5) are as follows: dimethylamine hydrochloride, formaldehyde solution and compound 11 are added sequentially to a thoroughly stirred acetic acid solution and stirred at room temperature. After the reaction is completed, the reaction solution is poured into water and the pH is adjusted to 8 with NaOH solution under ice bath conditions. The precipitated solid is collected by vacuum filtration and the obtained residue is dried to obtain a yellow intermediate, namely compound 12a.

[0021] In step (5), compounds 12b, 12c, 12d, and 12e are all carried out in accordance with the steps of 12a above, except that the corresponding ammonium salt dimethylamine hydrochloride is replaced with diethylamine hydrochloride, tetrahydropyrrole, piperidine, or morpholine.

[0022] The specific operation of the target compound A01 in step (6) is as follows: Sodium methoxide, formamide, and compound 12a are dissolved in N,N-dimethylformamide and stirred at 45~55℃. After the reaction is completed, the mixture is cooled to room temperature, the reaction solution is poured into ice water, the precipitated solid is collected by vacuum filtration and dried, and the target compound A01 is obtained by column chromatography purification.

[0023] The specific operations for the target compounds A02, A03, A04, and A05 in step (6) can be the same as those for the preparation of A01, except that the raw materials are replaced with compounds 12b, 12c, 12d, and 12e.

[0024] The FXa inhibitors mentioned above are used in the preparation of drugs for treating thrombotic diseases, mainly in anticoagulant drugs.

[0025] The preparation method of the FXa inhibitor described in this invention specifically includes the following process: the synthetic routes of the target compounds A01-A05 are as follows... Figure 1 As shown: Starting from p-nitroaniline, intermediate 5 was prepared by amide condensation, substitution, and cycloaddition. Starting from p-methoxyaniline, intermediate 10 was prepared by diazotization, cyclization, elimination, and nitro reduction. Intermediate 10 was reacted with 2,5-dimethoxytetrahydrofuran to obtain intermediate 11, which was then subjected to the Mannich reaction to obtain intermediates 12a-12e. Finally, the target compounds A01-A05 were obtained by ammonolysis.

[0026] Compared with the prior art, the beneficial effects of the present invention are: (1) This invention provides a novel class of pyrazolopyridine FXa inhibitors. By introducing pyrrole groups with different amine side chains onto the benzene ring of the apixaban nucleus, compounds with higher FXa enzyme inhibitory activity were successfully obtained.

[0027] (2) The compounds of the present invention exhibited excellent effects in prolonging coagulation time in in vitro anticoagulant activity evaluation.

[0028] (3) The preparation method provided by this invention has a reasonable design, the raw materials are inexpensive and readily available, the reaction conditions are mild, and it avoids the use of sensitive reagents such as trimethylaluminum and harsh operations such as catalytic hydrogenation. The post-processing is simple and the overall yield is high. At the same time, different amino side chains can be conveniently introduced onto the pyrrole ring through the Mannich reaction, which can quickly construct a library of compounds with diverse structures, providing an efficient technical platform for subsequent structure-activity relationship studies and drug development. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the synthesis process route of the present invention.

[0030] Figure 2 The ¹H NMR (hydrogen nuclear magnetic resonance) spectrum of compound A01 prepared in Example 1 is shown.

[0031] Figure 3 The ¹H NMR (hydrogen nuclear magnetic resonance) spectrum of compound A01 prepared in Example 2 is shown.

[0032] Figure 4 The ¹H NMR (hydrogen nuclear magnetic resonance) spectrum of compound A01 prepared in Example 3 is shown.

[0033] Figure 5 The ¹H NMR (hydrogen nuclear magnetic resonance) spectrum of compound A01 prepared in Example 4 is shown.

[0034] Figure 6 The ¹H NMR (hydrogen nuclear magnetic resonance) spectrum of compound A01 prepared in Example 5 is shown.

[0035] Figure 7 The HPLC spectrum of compound A01 prepared in Example 1 is shown.

[0036] Figure 8 The image shows the HPLC spectrum of compound A01 prepared in Example 2.

[0037] Figure 9 The image shows the HPLC spectrum of compound A01 prepared in Example 3.

[0038] Figure 10 The image shows the HPLC spectrum of compound A01 prepared in Example 4.

[0039] Figure 11 The image shows the HPLC spectrum of compound A01 prepared in Example 5. Detailed Implementation

[0040] The present invention will be further described below with reference to specific embodiments.

[0041] Example 1 The preparation method of the FXa inhibitor A01 includes the following steps: (1) Preparation of intermediate 5-chloro-N-(4-nitrophenyl)pentanamide (compound 2) At room temperature, 50.0 g of p-nitroaniline (0.36 mol) and 100 mL of triethylamine (0.72 mol) were dissolved in 200 mL of tetrahydrofuran. 70 mL of 5-chloropentanoyl chloride (0.54 mol) was slowly added dropwise at 0–5 °C. After the addition was complete, the mixture was stirred at room temperature for 6 h. After the reaction was complete, the reaction solution was poured into 200 mL of ice water, and a solid precipitated. The precipitate was filtered, washed with diethyl ether, and dried under reduced pressure to give 72.3 g of a yellow solid, namely target compound 2. The calculated yield was 77.8%. LC-MS (ESI) m / z (%): 257.1 [M+H] + .

[0042] (2) Preparation of intermediate 1-(4-nitrophenyl)piperidin-2-one (compound 3) 72.3 g of compound 2 (0.28 mol) and 57.9 g of potassium carbonate (0.42 mol) were added to 360 mL of dimethyl sulfoxide. The mixture was stirred at 80 °C for 6 h. After the reaction was completed, the mixture was cooled to room temperature and poured into 200 mL of ice water. A solid precipitated, which was filtered. The precipitate was washed with water and dried under reduced pressure to give 55.7 g of a yellow powder, namely compound 3. The yield was calculated to be 89.6%. LC-MS (ESI) m / z (%): 221.1 [M+H] + .

[0043] (3) Preparation of intermediate 3,3-dichloro-1-(4-nitrophenyl)piperidin-2-one (compound 4) 55.7 g of compound 3 (0.25 mol) was dissolved in 330 mL of dichloromethane and stirred until completely dissolved. Then, 158.0 g of phosphorus pentachloride (0.76 mol) was added, and the mixture was heated under reflux for 5 h. After the reaction was complete, the mixture was cooled to room temperature, and the reaction solution was poured into 300 mL of ice water. The aqueous layer was separated and extracted three times with 100 mL of dichloromethane each time. The combined organic phases were washed successively with 100 mL of water (washed three times) and 200 mL of saturated brine. The organic phase was dried over anhydrous sodium sulfate, filtered, and the solvent was removed by vacuum distillation. The residue was ground with methanol to obtain 50.3 g of white powder, which was compound 4. The yield was calculated to be 69.0%. LC-MS (ESI) m / z (%): 289.0 [M+H] + .

[0044] (4) Preparation of intermediate 3-morpholino-1-(4-nitrophenyl)-5,6-dihydropyridine-2(1H)-one (compound 5) 50.3 g of intermediate 4 (0.17 mol) was mixed with 200 mL of morpholine and stirred at 130 °C for 1.5 h. After the reaction was completed, the mixture was cooled to room temperature, and the solvent was removed under reduced pressure. The resulting precipitate was collected by suction filtration and washed with water to give 46.3 g of a yellow solid, which was the target compound 5. The yield was calculated to be 87.6%. LC-MS (ESI) m / z (%): 304.0 [M+H] + .

[0045] (5) Preparation of intermediate (Z)-2-chloro-2-(2-(4-methoxyphenyl)hydrazino)ethyl acetate (compound 7) At room temperature, 50 mL of hydrochloric acid (0.6 mol) was added to 0.20 mol of p-methoxyaniline aqueous solution (24.6 g methoxyaniline dissolved in 100 mL of water). The solution was stirred. After the addition was complete, 0.22 mol of sodium nitrite aqueous solution (15.2 g sodium nitrite dissolved in 30 mL of water) was added dropwise at -5 °C. After the addition was complete, the reaction system was stirred at 0 °C for 30 min. Then, 34.5 g of ethyl 2-chloroacetoacetate (0.21 mol) and 49.2 g of sodium acetate (0.60 mol) were added to the system, and the mixture was stirred for another 30 min. The reaction system was then heated to 25 °C and reacted for 2 h. After the reaction was complete, a solid precipitated. The solid was filtered, washed with methanol, and dried under reduced pressure to give 43.6 g of the yellow target compound, compound 7. The yield was calculated to be 85.1%. LC-MS (ESI) m / z (%): 257.1 [M+H] + .

[0046] (6) Preparation of intermediate 1-(4-methoxyphenyl)-7a-morpholino-6-(4-nitrophenyl)-7-oxo-3a,4,5,6,7,7a-hexahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ethyl ester (compound 8) 32 mL of triethylamine (0.23 mol) and 46.1 g of compound 7 (0.18 mol) were added to 0.15 mol of a solution of compound 5 (45.5 g of compound 5 dissolved in 500 mL of ethyl acetate). The mixture was stirred at 80 °C for 6 h. After the reaction was completed, the mixture was cooled to room temperature, and a yellow solid precipitated. The precipitate was filtered and washed with ethyl acetate to give 76.5 g of the yellow target compound, compound 8. The yield was calculated to be 97.5%. LC-MS (ESI) m / z (%): 524.2 [M+H] + .

[0047] (7) Preparation of intermediate 1-(4-methoxyphenyl)-6-(4-nitrophenyl)-7-oxo-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ethyl ester (compound 9) Trifluoroacetic acid was added dropwise to a 0.12 mol solution of compound 8 (62.8 g of compound 8 dissolved in 650 mL of dichloromethane solution) under ice bath conditions. After the addition was complete, the mixture was stirred at room temperature for 1 h. After the reaction was complete, the reaction solution was poured into 300 mL of ice water, the organic phase was separated, and the mixture was washed three times with 100 mL of water each time, followed by washing with 200 mL of saturated brine. The organic phase was dried over anhydrous sodium sulfate, filtered, and the solvent was evaporated under reduced pressure to obtain a reddish-brown solid. The solid was then ground with diethyl ether to obtain 32.5 g of a yellow intermediate, compound 9, with a yield of 62.1%. LC-MS (ESI) m / z (%): 437.1 [M+H] + .

[0048] (8) Preparation of intermediate 6-(4-aminophenyl)-1-(4-methoxyphenyl)-7-oxo-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ethyl ester (compound 10) 22.4 g of iron powder (0.40 mol), 1.7 mL of hydrochloric acid (0.02 mol), and 2.7 g of ammonium chloride (0.05 mol) were added to 350 mL of 90 wt% ethanol. The mixture was stirred vigorously at 80 °C for 30 min. Then, 43.6 g of compound 9 (0.10 mol) was added in portions, and the reaction was continued until the reaction was complete as monitored by TLC. The hot reaction solution was filtered while hot and washed with hot methanol. The filtrates were combined, and the solvent was evaporated under reduced pressure to obtain 32.7 g of target compound 10. The yield was calculated to be 80.5%. LC-MS (ESI) m / z (%): 407.1 [M+H] + .

[0049] (9) Preparation of intermediate 6-(4-(1H-pyrrolo-1-yl)phenyl)-1-(4-methoxyphenyl)-7-oxo-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ethyl ester (compound 11) 10.0 g of compound 10 (24.6 mmol) and 0.1 g of p-toluenesulfonic acid (0.6 mmol) were added to 3.4 mL of a tetrahydrofuran solution of 2,5-dimethoxytetrahydrofuran (23.0 mmol). The mixture was heated to 60 °C and reacted for 1 h. After the reaction was completed, the mixture was cooled to room temperature and washed three times with 30 mL of dichloromethane each time. The reaction solution was extracted, the organic phase was washed with water, and dried under reduced pressure to give 7.9 g of a yellow intermediate, compound 11, with a yield of 70.0%. LC-MS (ESI) m / z (%): 457.2 [M+H] + .

[0050] (10) Preparation of intermediate 6-(4-(2-((dimethylamino)methyl)-1H-pyrrolo-1-yl)phenyl)-1-(4-methoxyphenyl)-7-oxo-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ethyl ester (compound 12a) 0.42 g of dimethylamine hydrochloride (5.2 mmol), 0.2 g of 37 wt% formaldehyde solution (2.2 mmol), and 1 g of compound 11 (2.2 mmol) were sequentially added to 20.0 mL of acetic acid solution with thorough stirring. The mixture was stirred at room temperature for 1 h. After the reaction was complete, the reaction solution was poured into water, and the pH was adjusted to 8 with 10 wt% NaOH under ice bath conditions. The precipitated solid was collected by vacuum filtration and dried to give 0.76 g of a yellow intermediate, compound 12a, with a yield of 67.3%. LC-MS (ESI) m / z (%): 514.2 [M+H] + .

[0051] (11) Preparation of FXa inhibitor A01 0.12 g sodium methoxide (2.25 mmol), 0.47 g formamide (10.5 mmol), and 0.76 g compound 12a (1.5 mmol) were dissolved in 20 mL of N,N-dimethylformamide. The mixture was stirred at 50 °C for 4 h. After the reaction was completed, the mixture was cooled to room temperature and poured into ice water. The precipitated solid was collected by vacuum filtration, dried, and purified by column chromatography to obtain 0.32 g of the target compound A01. The yield was calculated to be 45.4%, and the purity was 99.32%. Its HPLC results are as follows: Figure 7 As shown, the data is presented in Table 1.

[0052] Melting point analysis: mp: 177.1-178.3℃.

[0053] 1HNMR(600MHz,DMSO-d6)δ(ppm):7.73(s,1H),7.60-7.55(m,2H),7.54-7.50(m,2H),7.48-7.43(m,3H),7.01(d,J=6.8Hz,2H),6.97 (t,J=2.3Hz,1H),6.18(q,J=4.7,3.2Hz,2H),4.10(t,J=6.6Hz,2H),3.81(s,3H),3.33(s,2H),3.23(t,J=6.6Hz,2H),2.15(s,6H), such as Figure 2 As shown.

[0054] LC-MS (ESI) m / z (%): 485.2 [M+H] + .

[0055] Table 1 Data Table

[0056] Example 2 The preparation method of the FXa inhibitor A02 includes the following steps: (1) Preparation of intermediate 6-(4-(2-((diethylamino)methyl)-1H-pyrrolo-1-yl)phenyl)-1-(4-methoxyphenyl)-7-oxo-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ethyl ester (compound 12b). 0.57 g of diethylamine hydrochloride (5.2 mmol), 0.2 g of 37 wt% formaldehyde solution (2.2 mmol), and 1 g of compound 11 (2.2 mmol) were sequentially added to 20.0 mL of acetic acid solution with thorough stirring. The mixture was stirred at room temperature for 1 h. After the reaction was complete, the reaction solution was poured into water, and the pH was adjusted to 8 with 10 wt% NaOH under ice bath conditions. The precipitated solid was collected by vacuum filtration and dried to give 0.77 g of compound 12b. The yield was calculated to be 65.1%. LC-MS (ESI) m / z (%): 542.2 [M+H] + .

[0057] (2) Preparation of FXa inhibitor A02 0.12 g sodium methoxide (2.25 mmol), 0.47 g formamide (10.5 mmol), and 0.80 g compound 12b (1.48 mmol) were dissolved in 20 mL of N,N-dimethylformamide. The mixture was stirred at 50 °C for 4 h. After the reaction was completed, the mixture was cooled to room temperature and poured into ice water. The precipitated solid was collected by vacuum filtration, dried, and purified by column chromatography to obtain 0.30 g of the target compound A02. The yield was calculated to be 40.8%, and the purity was 99.57%. The HPLC results are as follows: Figure 8 As shown, the data is presented in Table 2.

[0058] Melting point analysis: mp: 176.5-178.1℃.

[0059] 1HNMR(600MHz,DMSO-d6)δ(ppm):7.76-7.71(m,1H),7.58(d,J=8.2Hz,2H),7.54-7.50(m,2H),7.45(d,J=8.3Hz,3H),7.03-6.99(m,2H) ,6.93(s,1H),6.15(s,2H),4.08(t,J=6.6Hz,2H),3.81(s,3H),3.41(s,2H),3.23(t,J=6.6Hz,2H),2.42(s,4H),0.86(t,J=6.9Hz,6H), such as Figure 3 As shown.

[0060] LC-MS (ESI) m / z (%): 513.2 [M+H] + .

[0061] Table 2 Data Table

[0062] Example 3 The method for preparing the FXa inhibitor A03 includes the following steps: (1) Preparation of intermediate 1-(4-methoxyphenyl)-7-oxo-6-(4-(2-(pyrrolidine-1-ylmethyl)-1H-pyrrol-1-yl)phenyl)-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ethyl ester (compound 12c) 0.37 g tetrahydropyrrole (5.2 mmol), 37 wt% formaldehyde solution (0.2 g, 2.2 mmol), and 1 g compound 11 (2.2 mmol) were sequentially added to 20.0 mL of acetic acid solution with thorough stirring. The mixture was stirred at room temperature for 1 h. After the reaction was complete, the reaction solution was poured into water, and the pH was adjusted to 8 with 10 wt% NaOH under ice bath conditions. The precipitated solid was collected by vacuum filtration and dried to give 0.84 g of compound 12c. The yield was calculated to be 70.8%. LC-MS (ESI) m / z (%): 540.2 [M+H] + .

[0063] (2) Preparation of FXa inhibitor A03 0.12 g sodium methoxide (2.25 mmol), 0.47 g formamide (10.5 mmol), and 0.81 g compound 12c (1.5 mmol) were dissolved in 20 mL of N,N-dimethylformamide. The mixture was stirred at 50 °C for 4 h. After the reaction was completed, the mixture was cooled to room temperature and poured into ice water. The precipitated solid was collected by vacuum filtration, dried, and purified by column chromatography to obtain 0.41 g of the target compound A03. The yield was calculated to be 51.2%, and the purity was 98.35%. The HPLC results are as follows: Figure 9 As shown, the data is presented in Table 3.

[0064] Melting point analysis: mp: 169.1-170.9℃.

[0065] 1HNMR(600MHz,DMSO-d6)δ(ppm):7.72(s,1H),7.57(d,J=8.4Hz,2H),7.51(d,J=8.9Hz,2H),7.49-7.43(m,3H),7.01(d,J=8.9Hz,2H),6. 95(s,1H),6.22(s,1H),6.17(s,1H),4.10(t,J=6.6Hz,2H),3.81(s,3H),3.32(s,2H),3.23(t,J=6.6Hz,2H),2.50(s,4H),1.70(s,4H), such as Figure 4 As shown.

[0066] LC-MS (ESI) m / z (%): 511.2 [M+H] + .

[0067] Table 3 Data Table

[0068] Example 4 The preparation method of the FXa inhibitor A04 includes the following steps: (1) Preparation of intermediate 1-(4-methoxyphenyl)-7-oxo-6-(4-(2-(piperidin-1-ylmethyl)-1H-pyrrolo-1-yl)phenyl)-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ethyl ester (compound 12d) 0.44 g piperidine (5.2 mmol), 0.2 g (2.2 mmol) of 37 wt% formaldehyde solution, and 1 g of compound 11 (2.2 mmol) were sequentially added to 20.0 mL of acetic acid solution with thorough stirring. The mixture was stirred at room temperature for 1 h. After the reaction was complete, the reaction solution was poured into water, and the pH was adjusted to 8 with 10 wt% NaOH under ice bath conditions. The precipitated solid was collected by vacuum filtration and dried to give 0.87 g of compound 12d. The yield was calculated to be 71.4%. LC-MS (ESI) m / z (%): 554.2 [M+H] + .

[0069] (2) Preparation of FXa inhibitor A04 0.12 g sodium methoxide (2.25 mmol), 0.47 g formamide (10.5 mmol), and 0.83 g compound 12d (1.5 mmol) were dissolved in 20 mL of N,N-dimethylformamide. The mixture was stirred at 50 °C for 4 h. After the reaction was completed, the mixture was cooled to room temperature and poured into ice water. The precipitated solid was collected by vacuum filtration, dried, and purified by column chromatography to obtain 0.31 g of the target compound A04. The yield was calculated to be 38.2%, and the purity was 98.50%. The HPLC results are as follows: Figure 10 As shown, the data is presented in Table 4.

[0070] Melting point analysis: mp: 181.2-182.9℃.

[0071] 1HNMR(600MHz,DMSO-d6)δ(ppm):7.73(s,1H),7.62(d,J=8.0Hz,2H),7.54-7.50(m,2H),7.48-7.43(m,3H),7.03-6.99(m,2H),6. 96(s,1H),6.15(s,2H),4.10(t,J=6.6Hz,2H),3.81(s,3H),3.22(t,J=6.6Hz,4H),2.32(s,4H),1.46(s,4H),1.40–1.32(m,2H), such as Figure 5 As shown.

[0072] LC-MS (ESI) m / z (%): 525.2 [M+H] + .

[0073] Table 4 Data Table

[0074] Example 5 The preparation method of the FXa inhibitor A05 includes the following steps: (1) Preparation of intermediate 1-(4-methoxyphenyl)-6-(4-(2-(morpholinomethyl)-1H-pyrrolo-1-yl)phenyl)-7-oxo-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ethyl ester (compound 12e) 0.45 g of morpholine (5.2 mmol), 0.2 g of 37 wt% formaldehyde solution (2.2 mmol), and 1 g of compound 11 (2.2 mmol) were sequentially added to 20.0 mL of acetic acid solution with thorough stirring. The mixture was stirred at room temperature for 1 h. After the reaction was complete, the reaction solution was poured into water, and the pH was adjusted to 8 with 10 wt% NaOH under ice bath conditions. The precipitated solid was collected by vacuum filtration and dried to give 0.98 g of compound 12e. The yield was calculated to be 80.4%. LC-MS (ESI) m / z (%): 556.2 [M+H] + .

[0075] (2) Preparation of FXa inhibitor A05 0.12 g sodium methoxide (2.25 mmol), 0.47 g formamide (10.5 mmol), and 0.83 g compound 12e (1.5 mmol) were dissolved in 20 mL of N,N-dimethylformamide. The mixture was stirred at 50 °C for 4 h. After the reaction was completed, the mixture was cooled to room temperature and poured into ice water. The precipitated solid was collected by vacuum filtration, dried, and purified by column chromatography to obtain 0.51 g of the target compound A05. The yield was calculated to be 55.5%, and the purity was 98.98%. The HPLC results are as follows: Figure 11 As shown, the data is presented in Table 5.

[0076] Melting point analysis: mp: 175.2-176.9℃.

[0077] 1HNMR(600MHz,DMSO-d6)δ(ppm):7.72(s,1H),7.62(d,J=8.7Hz,2H),7.54-7.50(m,2H),7.47-7.43(m,3H),7.01(dd,J=9.6,2.6Hz,2H),6.9 6(t,J=2.2Hz,1H),6.15(d,J=2.7Hz,2H),4.10(t,J=6.6Hz,2H),3.81(s,3H),3.53(s,4H),3.30(s,2H),3.23(t,J=6.6Hz,2H),2.33(s,4H), such as Figure 6 As shown.

[0078] LC-MS (ESI) m / z (%): 527.2 [M+H] + .

[0079] Table 5 Data Table

[0080] The inhibitors A01, A02, A03, A04, and A05 prepared according to the present invention were subjected to the following tests: I. FXa Inhibition Results (IC) 50 ) 1. Experimental Materials and Instruments Test compounds: Compounds A01 to A05 prepared in Examples 1 to 5.

[0081] Positive control: Apixaban.

[0082] Enzyme: Human FXa (coagulation factor Xa).

[0083] Substrate: Chromogenic substrate CH3OCO-D-Cha-Gly-Arg-pNA,AcOH (methoxycarbonyl-D-cyclohexylalanyl-glycyl-arginine p-nitroaniline acetate).

[0084] Buffer: 1× reaction buffer (containing 0.1 mol / L Tris, 0.1 mol / L NaCl, 5 mmol / L CaCl2, 0.1% BSA, pH 8.4).

[0085] Instruments: Synergy2 multi-functional microplate reader, Echo550 ultrasonic pipetting system, 384-well reaction plate.

[0086] 2. Solution preparation (1) Stock solution of the test compound: Weigh an appropriate amount of the test compound powder, dissolve it in 100% DMSO, prepare a 10 mmol / L stock solution, and store it in the dark for later use.

[0087] (2) Compound concentration gradient: The test compounds were serially diluted with 100% DMSO in a 384-well Source plate. The test compounds were started at a concentration of 1 μmol / L and serially diluted 5-fold to set 8 concentration points, with 2 replicates for each concentration. The positive control apixaban was started at a concentration of 300 nmol / L and serially diluted 3-fold to set 10 concentration points, with 2 replicates for each concentration. Max wells (containing DMSO and enzyme) and Min wells (without enzyme) were set as controls, with 20 μL of 100% DMSO transferred to each well.

[0088] (3) 2× enzyme solution: Prepare a 2-fold concentrated solution containing FXa enzyme using 1× reaction buffer.

[0089] (4) 2× substrate solution: Prepare a 2× concentrated solution containing the substrate using 1× reaction buffer.

[0090] 3. Experimental Procedure (1) Transfer 20 μL of the diluted compound solution in the 384-well Source plate to the 384-well reaction plate for testing using an Echo550.

[0091] (2) Add 10 μL of 2× enzyme solution to each compound well and the Max well of the reaction plate; add 10 μL of 1× reaction buffer (without enzyme) to the Min well. Centrifuge the reaction plate at 1000 rpm for 1 min and incubate at room temperature for 15 min.

[0092] (3) Add 10 μL of 2× substrate solution to each well of the reaction plate to start the enzyme reaction.

[0093] (4) Immediately use the Synergy2 microplate reader to continuously read the fluorescence signal (detection wavelength 405nm) and record the reaction curve.

[0094] 4. Data Processing and ICs 50 calculate (1) Select the linear reaction segment from the reaction curves of each well and calculate the slope.

[0095] (2) Calculate the inhibition rate (%Inhibition) at each concentration using the following formula: , in: Mean(Max): The average slope value of all Max wells (including DMSO and enzyme); Mean(Min): The average slope value of all Min wells (enzyme-free); SampleSignal: The slope value of the pores of the compound to be tested.

[0096] (3) Fitting dose-response curves: Using the common logarithm of compound concentration (logC) as the X-axis and the inhibition rate as the Y-axis, the dose-response curves were fitted using the "log(inhibitor) vs. response – Variable slope" model in GraphPadPrism5 software to obtain the IC50 values ​​of each compound. 50 Values. The results are shown in Table 6.

[0097] Table 6. IC50 values ​​of the enzyme-inhibiting activities of compounds A01-A05 50 value

[0098] II. Results of in vitro PT and APPT experiments 1. Experimental Materials APTT and PT reagent kits were purchased from Taizhou Zhongqinshi Biotechnology Co., Ltd.

[0099] Freeze-dried rabbit plasma (containing 3.8% sodium citrate): purchased from Qingdao Haibo Biotechnology Co., Ltd.

[0100] Automated coagulation analyzer: used to record coagulation time.

[0101] Test compounds: Compounds A01 to A05 prepared in Examples 1 to 5.

[0102] Positive control: Apixaban.

[0103] Solvent: DMSO.

[0104] 2. Experimental Methods 2.1 APTT assay (activated partial thromboplastin time) Preheat the APTT reagent and CaCl2 solution to 37°C. Add 90 μL of lyophilized rabbit plasma and 10 μL of different concentrations of the test compound solution (dissolved in DMSO) sequentially to the incubation vessel of the automated coagulation analyzer. A solvent control group (containing 10 μL of DMSO) is also included. Incubate the vessel at 37°C for 3 minutes. Then add 100 μL of preheated APTT reagent and continue incubating at 37°C for 3 minutes. Finally, add 100 μL of preheated CaCl2 solution to initiate the coagulation reaction and record the coagulation time.

[0105] 2.2 PT Measurement (Prothrombin Time) Preheat the PT reagent to 37°C. Add 90 μL of lyophilized rabbit plasma and 10 μL of different concentrations of the test compound solution (dissolved in DMSO) sequentially to the incubation vessel of the automated coagulation analyzer. Simultaneously, set up a solvent control group (containing 10 μL of DMSO). Incubate the vessel at 37°C for 3 min. Then add 200 μL of preheated PT reagent to initiate the coagulation reaction and record the coagulation time.

[0106] 3. Data Processing and EC 2X calculate Plotting compound concentration on the x-axis and corresponding clotting time on the y-axis, GraphPadPrism5 software was used for curve fitting to calculate the compound concentration that extended clotting time to twice that of the solvent control group, denoted as EC. 2x (Unit: μmol / L).

[0107] 4. Experimental Results The effects of each compound on PT and APTT were determined using the method described above, and the results are shown in Table 7.

[0108] Table 7 Effects of compounds on PT and APTT

[0109] Compounds A01, A02, and A03 of this invention all achieved or outperformed the positive control apixaban in terms of FXa enzyme inhibition activity and in vitro coagulation time prolongation, with A03 being the optimal candidate compound. Although A04 and A05 have anticoagulant activity, their effects are relatively inferior to A01, A02, and A03.

Claims

1. An FXa inhibitor, characterized in that, The general structural formula is: , where R1 is , , , or .

2. A method for preparing the FXa inhibitor according to claim 1, characterized in that, Includes the following steps: (1) Starting with p-nitroaniline, it undergoes an amide condensation reaction with 5-chloropentanoyl chloride to generate compound 5-chloro-N-(4-nitrophenyl)pentanoamide. Compound 5-chloro-N-(4-nitrophenyl)pentanoamide undergoes an intramolecular nucleophilic substitution cyclization reaction under alkaline conditions to generate compound 1-(4-nitrophenyl)piperidin-2-one. Compound 1-(4-nitrophenyl)piperidin-2-one undergoes a carbonyl α-position chlorination reaction under strong chlorination conditions to generate compound 3,3-dichloro-1-(4-nitrophenyl)piperidin-2-one. Compound 3,3-dichloro-1-(4-nitrophenyl)piperidin-2-one undergoes a nucleophilic substitution-elimination tandem reaction with morpholine to obtain compound 3-morpholino-1-(4-nitrophenyl)-5,6-dihydropyridine-2(1H)-one; (2) Using p-methoxyaniline as the starting material, sodium nitrite and hydrochloric acid were added to react and generate a diazonium salt. Then, ethyl 2-chloroacetoacetate was added to carry out a coupling reaction to obtain compound (Z)-2-chloro-2-(2-(4-methoxyphenyl)hydrazyl)ethyl acetate. (3) Compound 3-morpholino-1-(4-nitrophenyl)-5,6-dihydropyridine-2(1H)-one and compound (Z)-2-chloro-2-(2-(4-methoxyphenyl)hydrazino)ethyl acetate were mixed and subjected to a cycloaddition reaction to obtain compound 1-(4-methoxyphenyl)-7a-morpholino-6-(4-nitrophenyl)-7-oxo-3a,4,5,6,7,7a-hexahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ethyl ester; (4) Compound 1-(4-methoxyphenyl)-7a-morpholino-6-(4-nitrophenyl)-7-oxo-3a,4,5,6,7,7a-hexahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ethyl ester was subjected to an acid-catalyzed elimination reaction with a strong acid to generate compound 1-(4-methoxyphenyl)-6-(4-nitrophenyl)-7-oxo-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ethyl ester; iron powder was mixed with ammonium chloride and acid was added, and compound 1-(4-methoxyphenyl)-6-(4-nitrophenyl)-7-oxo-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ethyl ester was added in batches. Ethyl 6-carboxylic acid ester is reacted with p-toluenesulfonic acid and 2,5-dimethoxytetrahydrofuran to produce ethyl 6-(4-aminophenyl)-1-(4-methoxyphenyl)-7-oxo-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ester. The mixture of ethyl 6-(4-aminophenyl)-1-(4-methoxyphenyl)-7-oxo-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ester and p-toluenesulfonic acid and 2,5-dimethoxytetrahydrofuran yields ethyl 6-(4-(1H-pyrrolo-1-yl)phenyl)-1-(4-methoxyphenyl)-7-oxo-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ester. (5) Compound 6-(4-(1H-pyrrolo-1-yl)phenyl)-1-(4-methoxyphenyl)-7-oxo-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid ethyl ester, amine source, and formaldehyde solution were added to acetic acid and reacted at room temperature to generate the compound Mannich base; (6) The compound Mannich base, sodium methoxide and formamide were mixed and dissolved in a solvent to carry out an amidation reaction to obtain the FXa inhibitor.

3. The method for preparing the FXa inhibitor according to claim 2, characterized in that, The specific steps for generating compound 5-chloro-N-(4-nitrophenyl)pentanamide in step (1) are as follows: at room temperature, p-nitroaniline and triethylamine are dissolved in tetrahydrofuran, and 5-chloropentanyl chloride is added dropwise at 0~5℃. After the addition is complete, the reaction is stirred at room temperature. After the reaction is completed, the reaction solution is poured into ice water to precipitate the precipitate. The precipitate is filtered, washed, and dried under reduced pressure to obtain compound 5-chloro-N-(4-nitrophenyl)pentanamide.

4. The method for preparing the FXa inhibitor according to claim 3, characterized in that, The specific steps for generating compound 1-(4-nitrophenyl)piperidin-2-one in step (1) are as follows: 5-chloro-N-(4-nitrophenyl)pentanamide and potassium carbonate are added to dimethyl sulfoxide and stirred at 75~85℃. After the reaction is completed, the mixture is cooled to room temperature, the reaction solution is poured into ice water, a precipitate is formed, the precipitate is filtered, the precipitate is washed and dried under reduced pressure to obtain compound 1-(4-nitrophenyl)piperidin-2-one.

5. The method for preparing the FXa inhibitor according to claim 4, characterized in that, The specific steps for generating compound 3,3-dichloro-1-(4-nitrophenyl)piperidin-2-one in step (1) are as follows: Dissolve compound 1-(4-nitrophenyl)piperidin-2-one in dichloromethane, stir to dissolve, add phosphorus pentachloride, heat to reflux reaction, cool to room temperature after the reaction is completed, pour the reaction solution into ice water, separate the aqueous layer, extract with dichloromethane, wash and dry the organic phase, filter, distill under reduced pressure, and grind to obtain compound 3,3-dichloro-1-(4-nitrophenyl)piperidin-2-one.

6. The method for preparing the FXa inhibitor according to claim 5, characterized in that, The specific steps for generating compound 3-morpholino-1-(4-nitrophenyl)-5,6-dihydropyridine-2(1H)-one in step (1) are as follows: 3,3-dichloro-1-(4-nitrophenyl)piperidin-2-one is mixed with morpholine and stirred at 25~135℃. After the reaction is completed, the mixture is cooled to room temperature and distilled under reduced pressure. The resulting precipitate is filtered and washed to obtain compound 3-morpholino-1-(4-nitrophenyl)-5,6-dihydropyridine-2(1H)-one.

7. The method for preparing the FXa inhibitor according to claim 2, characterized in that, The specific steps of step (2) are as follows: under room temperature conditions, hydrochloric acid is added to the aqueous solution of p-methoxyaniline and stirred. After the addition is completed, sodium nitrite aqueous solution is added dropwise at -5~0℃. After the addition is completed, the reaction system is stirred at -5~0℃. Then, ethyl 2-chloroacetoacetate and sodium acetate are added and stirred. Then the reaction system is heated to 20~30℃ and reacted. After the reaction is completed, a precipitate is precipitated, filtered, and the precipitate is washed and dried under reduced pressure to obtain compound (Z)-2-chloro-2-(2-(4-methoxyphenyl)hydrazyl)ethyl acetate.

8. The method for preparing the FXa inhibitor according to claim 2, characterized in that, The specific steps of step (3) are as follows: triethylamine and ethyl acetate of compound (Z)-2-chloro-2-(2-(4-methoxyphenyl)hydrazino) are added to an ethyl acetate solution of compound 3-morpholino-1-(4-nitrophenyl)-5,6-dihydropyridine-2(1H)-one. The reaction is stirred at 75~85℃. After the reaction is completed, the mixture is cooled to room temperature, and a precipitate is formed. The precipitate is filtered and washed to obtain ethyl 1-(4-methoxyphenyl)-7a-morpholino-6-(4-nitrophenyl)-7-oxo-3a,4,5,6,7,7a-hexahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylic acid.

9. The method for preparing the FXa inhibitor according to any one of claims 2 to 8, characterized in that, The amine source in step (5) is dimethylamine hydrochloride, diethylamine hydrochloride, tetrahydropyrrole, piperidine, or morpholine.

10. The use of the FXa inhibitor as described in claim 1 in the preparation of a medicament for treating thrombotic diseases.

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