Mabavir impurity and preparation method thereof

Abstract

The invention belongs to the technical field of medicine synthesis, and particularly relates to a macloxvir impurity and a preparation method thereof. The impurity is prepared by reacting a macloxvir key intermediate compound as shown in a formula II with a halogenated formate compound in the presence of alkali. The preparation method of the macarovir process impurity provided by the invention is simple in preparation process, high in product purity, good in safety and suitable for industrial production, provides a standard reference substance and a detection method for quality research of raw material medicines of macarovir, greatly reduces the difficulty of quality research of macarovir, and has a good application prospect. Therefore, contributions are made to research on the quality of active pharmaceutical ingredients of macloxvir.

Description

Technical Field

[0001] The invention belongs to the technical field of pharmaceutical synthesis, and particularly relates to an impurity of mabaloxavir and a preparation method thereof. Background Art

[0002] Mabaloxavir is a prodrug that is hydrolyzed by arylacetamide deacetylase (AADAC) into baloxavir, an active ingredient with anti-influenza virus effects, after entering the human body. Baloxavir inhibits the activity of influenza virus RdRp by binding to PA protein (i.e., Cap-dependent endonuclease) with endonuclease activity, blocking the synthesis of viral mRNA, thereby inhibiting viral proliferation and exerting an antiviral effect. Currently, mabaloxavir is approved for the treatment of influenza A and B in more than 70 countries.

[0003] In the process of preparing the raw material of Mabaloxavir, the active ingredient baloxavir undergoes an ester exchange side reaction with methyl chloromethyl carbonate to form compounds of Formula III and Formula IV. These compounds are key process impurities of Mabaloxavir. In order to ensure the full and accurate study of these impurities, we have developed a preparation method for these compounds.

[0004]

[0005] US Patent (US10392406) discloses compounds of Mabaloxavir, and also reports compounds having Formula III, but there is no relevant report on the preparation method of such compounds. Therefore, we tried the following preparation method: Method 1:

[0006] The method is to prepare the compound of formula I by condensing formula II and carbonate monoester to form an ester under the action of a condensing agent. The carbonate monoester, a reaction substrate involved in the method, is prone to spontaneous combustion, and there is a great safety hazard during use.

[0007] Method 2:

[0008] The method is to carry out ester exchange reaction between the compound of formula II and methyl carbonate under the catalysis of DBU to prepare the compound of formula I. The reaction involved in the preparation method is relatively mild, but the reaction conversion rate is low.

[0009] Method 3:

[0010] The method is to prepare the compound of formula I by carbonylation reaction of formula II and fatty alcohol under the action of CDI. The method has many side reactions, low reaction conversion rate and difficult post-processing purification.

[0011] Therefore, providing a method for preparing the compounds of formula III and formula IV with mild reaction, high reaction conversion rate and high safety is of great significance for improving the drug quality control of mabaloxavir. Summary of the invention

[0012] The purpose of the present invention is to solve the problem that the prior art lacks a method for preparing key process impurities of mabaloxavir, and to provide a method for preparing key process impurities of mabaloxavir which has simple process, high preparation purity and is suitable for industrial production.

[0013] To achieve the above object, the technical solution of the present invention is: The present invention provides a method for preparing a compound of formula I, which comprises: in the presence of a base, reacting a compound of formula II with a compound of formula The compound reacts, and the reaction route is:

[0014] Wherein, the structural formulas of Formula I and Formula II are:

[0015] R is selected from unsubstituted alkyl, halogenated alkyl or aryl, and X is selected from Cl or Br.

[0016] Preferably, R is selected from methyl or chloromethyl, X is selected from Cl, and the structure is shown in Formula III and Formula IV:

[0017] According to an embodiment of the present invention, the inventors found that the difficulty in the reaction process is that The amount of the compound used and the type of reaction base used. If the alkalinity of the reaction base is too strong, the formed product will be degraded, thereby reducing the reaction yield. If the amount of the compound used is too small, the reaction will be incomplete, resulting in a low product yield. If the amount used is too high, the quaternary ammonium salt by-products will increase, resulting in a lower product yield. For details, see Examples 2 and 3.

[0018] Preferably, the compound of formula II and The molar ratio of the compounds is selected from 1:1.00 to 1.50.

[0019] The base used in the reaction is selected from one or more of triethylamine, diisopropylethylamine, pyridine, sodium bicarbonate, sodium carbonate, potassium bicarbonate, potassium carbonate, dipotassium hydrogen phosphate, potassium phosphate, and cesium carbonate, and the molar ratio of the compound of formula II to the base is selected from 1:1.00~2.00.

[0020] According to an embodiment of the present invention, the reaction solvent uses an aprotic solvent, which is selected from one or more of dichloromethane, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, acetone, 1,4-dioxane, acetonitrile, chloroform, and 1,2-dichloroethane.

[0021] Preferably, in the preparation method, the mass volume ratio of the compound of formula II to the reaction solvent is 1:5-10.

[0022] According to an embodiment of the present invention, the reaction temperature is not limited, but the reaction can usually be carried out at -20°C to 100°C, preferably at 0~30°C.

[0023] According to an embodiment of the present invention, the reaction time is not limited, but the reaction can usually be carried out for 0.5 h to 24 h, preferably 1 to 10 h.

[0024] The present invention also provides a method for detecting the compound of formula (I) in mabaloxavir, comprising: (1) Dilution solution: solution A (0.1% trifluoroacetic acid solution containing 0.5 mmol / L disodium ethylenediaminetetraacetate)-acetonitrile (1:3); (2) Test solution: Take an appropriate amount of the product, dissolve it in diluent and dilute it to a solution containing approximately 0.4 mg of mabaloxavir per 1 ml; (3) Chromatographic conditions: Use octadecylsilane bonded silica gel as filler (Waters XSelect CSH column, 4.6 mm × 150 mm, 3.5 μm or chromatographic column with equivalent performance); use solution A as mobile phase A, acetonitrile as mobile phase B, column temperature at 60 °C, and perform gradient elution as shown in the table below; flow rate at 0.6 ml per minute; column temperature at 35 °C; detection wavelength at 259 nm; injection volume at 5 μl, gradient elution program as follows: ; (4) Determination method: Accurately measure the test sample solution, inject it into the liquid chromatograph, and record the chromatogram.

[0025] Beneficial effects of the present invention: The method for preparing the process impurities of mabaloxavir provided by the present invention has a simple preparation process, high product purity, good safety, and is suitable for industrial production. It provides a standard reference substance and a detection method for the quality research of the raw material of mabaloxavir, greatly reduces the difficulty of the quality research of mabaloxavir, and thus contributes to the quality research of the raw material of mabaloxavir. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is the mass spectrum of the compound of formula III.

[0027] Figure 2 The compound of formula III 1H-NMR spectrum. Figure 3 It is the HPLC spectrum of the compound of formula III.

[0028] Figure 4 is the mass spectrum of the compound of formula IV.

[0029] Figure 5 The HPLC spectrum of the compound of formula IV is shown in FIG.

[0030] Figure 6 HPLC profile of Mabaloxavir. DETAILED DESCRIPTION Example 1

[0031] Preparation of compound of formula III At room temperature, 2.32 g (4.80 mmol, 1.00 equivalent) of the compound of formula II and 0.73 g (7.20 mmol, 1.40 equivalent) of triethylamine were mixed in 20 ml of dichloromethane and stirred to dissolve, followed by adding 0.54 g (5.76 mmol, 1.20 equivalent) of methyl chloroformate. After stirring and reacting at room temperature for 8 hours, 20 ml of water was added to the reaction solution for washing and extraction. After standing and separating the liquids, the lower organic phase was retained, dried over anhydrous sodium sulfate, and concentrated to dryness under reduced pressure to obtain a white solid powder of the compound of formula III (2.18 g, yield 83.85%, purity 99.25%), M ＋ =542.1. 1 H-NMR (400 MHz, DMSO) δ: 7.53 – 7.45(m, 1H), 7.39 (dd, J = 18.1, 8.4 Hz, 1H), 7.33 (d, J = 7.8 Hz, 1H), 7.19 –7.13 (m, 1H), 7.12 – 7.07 (m, 1H), 7.01 (d, J = 7.2 Hz, 1H), 6.83 (t, J = 7.2Hz, 1H), 5.82 (d, J = 7.8 Hz, 1H), 5.74 (d, J = 15.2 Hz, 1H), 5.47 (d, J =14.5 Hz, 1H), 4.50 (d, J = 7.5 Hz, 1H), 4.41 (d, J = 11.7 Hz, 1H), 4.06 (d, J= 14.4 Hz, 1H), 3.98 (d, J = 9.5 Hz, 1H), 3.87 (s, 3H), 3.68 (dd, J = 11.3,2.4 Hz, 1H), 3.57 (s, 1H), 3.05 – 2.92 (m, 1H). Example 2

[0032] Comparison of reaction base types prepared from compounds of formula III Specific implementation method As shown in Example 1, we tried to use different types of reaction bases (listed in the following table) with the same equivalent (1.40 equivalents relative to 1 mole of compound of formula II) to prepare compound of formula III, and the corresponding reaction yield and product purity are shown in the following table: Table 1 Effect of different reaction bases on the preparation of compounds of formula III Example 3

[0033] Comparison of the amount of methyl chloroformate prepared by the compound of formula III Specific implementation method As shown in Example 1, we tried to use different equivalents (relative to 1 molar equivalent of compound II, as listed in the following table) of methyl chloroformate to prepare compound III, and the corresponding reaction yield and product purity are shown in the following table: Table 2 Effect of different equivalents of methyl chloroformate on the preparation of compounds of formula III Example 4

[0034] Preparation of compound of formula III At room temperature, 2.00 g (4.14 mmol, 1.00 equivalent) of the compound of formula II and 0.03 g (0.21 mmol, 0.05 equivalent) of DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) were mixed in 20 ml of tetrahydrofuran and stirred to dissolve, followed by adding 0.75 g (8.33 mmol, 2.01 equivalent) of dimethyl carbonate, and the temperature was raised to reflux for reaction for 24 hours, and the reaction solution was concentrated and separated by column chromatography to obtain a white solid powder of the compound of formula III (0.45 g, yield 20.09%, purity 98.32%), [M+H] ＋ =542.1. Example 5

[0035] Preparation of compounds of formula IV At room temperature, 8.00 g (16.55 mmol) of the compound of formula II and 2.51 g (24.82 mmol) of triethylamine were mixed in 80 ml of dichloromethane and stirred to dissolve, then placed in an ice-water bath to cool to -10°C, chloromethyl chloroformate was added dropwise, and after the addition was completed, the reaction was kept warm for 10 hours, 80 ml of water was added to the reaction solution for washing and extraction, and after standing and separating the liquids, the lower organic phase was retained, dried over anhydrous sodium sulfate, and separated by column chromatography to obtain a white solid powder of the compound of formula IV (5.70 g, yield 54.28%, purity 91.47%), [M+H] ＋ =576.1. Example 6

[0036] Preparation of Mabaloxavir At room temperature, 6.37 g (13.18 mmol) of the compound of formula II and 1.80 g (14.49 mmol) of dimethyl chloromethyl carbonate were mixed in 30 ml of DMF, stirred and dissolved until clear, and then a catalytic amount of potassium iodide and 2.73 g (19.76 mmol) of potassium carbonate were added, and the mixture was heated to 80±5° C. for 8 hours. 30 ml of water was added to the reaction solution to quench the reaction, and 60 ml of EA was used for extraction. Column chromatography was performed to separate 5.23 g of mabaloxavir, which was subjected to mass analysis. The relevant detection methods are as follows: Dilution solution: Solution A (0.1% trifluoroacetic acid solution containing 0.5 mmol / L disodium ethylenediaminetetraacetate)-acetonitrile (1:3).

[0037] Test solution: Take an appropriate amount of the product, dissolve it in diluent and dilute it to a solution containing approximately 0.4 mg of mabaloxavir per 1 ml.

[0038] Chromatographic conditions: octadecylsilane bonded silica gel as filler (Waters XSelect CSH column, 4.6 mm × 150 mm, 3.5 μm or chromatographic column with equivalent performance); solution A as mobile phase A, acetonitrile as mobile phase B, column temperature at 60 ° C, gradient elution as shown in the table below; flow rate 0.6 ml per minute; column temperature 35 ° C; detection wavelength 259 nm; injection volume 5 μl, gradient elution program: ; Determination method: Accurately measure the test solution, inject it into the liquid chromatograph, and record the chromatogram.

[0039] Detection spectrum such as Figure 6As shown, it is inevitable to produce a by-product of the compound of formula III in the process of preparing mabaloxavir. Due to the poor stability of the compound of formula IV, it has been degraded into a compound of formula II during the process. However, studying the standard compound of formula IV is of great significance for the control of intermediates in the synthesis process of mabaloxavir.

Claims

1. A method for preparing a compound of formula I, It is characterized in that The method is as follows: in the presence of a base, a compound of formula II and a Compound reaction, wherein the structures of Formula I and Formula II are: R is selected from unsubstituted alkyl, halogenated alkyl or aryl, and X is selected from Cl or Br.

2. A method for preparing a compound of formula I according to claim 1, It is characterized in that The R is selected from methyl or chloromethyl, and X is selected from Cl.

3. A method for preparing a compound of formula I according to claim 1, It is characterized in that The compound of formula II and the compound of formula The molar ratio of the compounds is selected from 1:1.00 to 1.

50.

4. A method for preparing a compound of formula I according to claim 1, It is characterized in that The base is selected from one or more of triethylamine, diisopropylethylamine, pyridine, sodium bicarbonate, sodium carbonate, potassium bicarbonate, potassium carbonate, dipotassium hydrogen phosphate, potassium phosphate, and cesium carbonate.

5. A method for preparing a compound of formula I according to claim 4, It is characterized in that The molar ratio of the compound of formula II to the base is selected from 1:1.00 to 2.

00.

6. A method for preparing a compound of formula I according to claim 1, It is characterized in that The reaction solvent in the reaction is selected from one or more of dichloromethane, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, acetone, 1,4-dioxane, acetonitrile, chloroform, and 1,2-dichloroethane.

7. A method for preparing a compound of formula I according to claim 6, It is characterized in that In the preparation method, the mass volume ratio of the compound of formula II to the reaction solvent is 1:5-10.

8. A method for preparing a compound of formula I according to claim 1, It is characterized in that The reaction temperature in the reaction is selected from 0~30°C.

9. A method for preparing a compound of formula I according to claim 1, It is characterized in that The reaction time in the reaction is selected from 1 to 10 hours.

10. A method for detecting the compound of formula (I) in mabaloxavir, It is characterized in that The method includes: (1) Dilution solution: Solution A, containing 0.5 mmol / L disodium ethylenediaminetetraacetic acid in 0.1% trifluoroacetic acid solution-acetonitrile, with a volume ratio of 1:3; (2) Test solution: Take an appropriate amount of the product, dissolve it in diluent and dilute it to a solution containing approximately 0.4 mg of mabaloxavir per 1 ml; (3) Chromatographic conditions: Use Waters XSelect CSH column, 4.6 mm × 150 mm, 3.5 μm or equivalent performance column; solution A as mobile phase A, acetonitrile as mobile phase B, column temperature at 60 °C, gradient elution according to the following table; flow rate 0.6 ml / min; column temperature 35 °C; detection wavelength 259 nm; injection volume 5 μl, gradient elution program: ； (4) Determination method: Accurately measure the test sample solution, inject it into the liquid chromatograph, and record the chromatogram.

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