Efficient synthesis method of 3-oxo-4, 22-diene cholanic acid-24 methyl ester

Abstract

The invention discloses an efficient synthesis method of 3-oxo-4, 22-diene cholanic acid-24 methyl ester, which comprises the following steps: (1) adding 3-oxo-4, 22-diene cholanic acid and a switching reagent into a first solvent, mixing and dissolving until the reaction liquid is clear; and (2) concentrating and distilling the reaction liquid in the step (1) to remove the first solvent, then adding a second solvent, adding halide salt and triphenylphosphine oxide to form a complex precipitate, filtering, washing a filter cake by using the second solvent, and drying to obtain the high-purity 3-oxo-4, 22-diene cholanic acid-24 methyl ester. The synthesis method and purification process of 3-oxo-4, 22-diene cholanic acid-24 methyl ester provided by the invention have the advantages of mild conditions and simple operation, and are convenient for industrial application. The purity of the 3-oxo-4, 22-diene cholanic acid-24 methyl ester synthesized by the method provided by the invention reaches 99.6%, and the yield of the 3-oxo-4, 22-diene cholanic acid-24 methyl ester reaches 95.7%.

Description

(I) Technical field

[0001] The invention belongs to the technical field of drug synthesis, and in particular relates to a high-efficiency synthesis method of lithocholic acid intermediate 3-oxo-4,22-dienecholanoic acid-24 methyl ester. (II) Background technology

[0002] Lithocholic acid (3α-hydroxy-5β-cholanoic acid, as shown in Formula I) is a secondary bile acid, also known as cholelithic acid, which exists in the bile of higher vertebrates. The change of its content has important reference value in the diagnosis of liver diseases. Lithocholic acid has a wide range of biological activities, such as activating vitamin D receptors, inhibiting the activity of diabetes-related target PTP1B, activating TGR5 receptors, antibacterial and antifungal, anti-aging activities, and especially the compound has anti-tumor activity. In recent years, studies have found that lithocholic acid can inhibit the mutation of DNA polymerase β and reduce the probability of tumors caused by DNA polymerase β mutation.

[0003]

[0004] The document (Organic Preparations and Procedures International.2022,4,355-362) reports a method for chemically synthesizing lithocholic acid. In this document, petroleum ether beating method is used to synthesize and purify 3-oxo-4,22-dienecholanoic acid-24 methyl ester. This method requires that the product purity must be higher than 60% to achieve a relatively ideal purification effect. If the purity is not enough, silica gel purification is required first. Therefore, this method has certain limitations.

[0005] The document (Science Direct.2020,157,108600) reported a method for chemically synthesizing ursodeoxycholic acid. In this document, silica gel column chromatography was used to purify 3-oxo-4,22-dienecholic acid-24-methyl ester. This method requires the use of a large amount of organic solvents and silica gel, which is not environmentally friendly, and can only separate relatively large amounts (gram levels) of substances, and the process cannot be scaled up.

[0006] The document (ACS Omega.2023,8,23130-23141) reports a chemical method for synthesizing lithocholic acid. The solvent crystallization method used in the document synthesizes and purifies 3-oxo-4,22-diene cholanoic acid-24 methyl ester. This method requires the use of a large amount of inorganic acid and alkali and organic solvents, and the crystallization mother liquor contains a large amount of 3-oxo-4,22-diene cholanoic acid-24 methyl ester that cannot be recovered, which is not suitable for industrial production. The main reason is that a large amount of by-product triphenylphosphine will be produced during the synthesis of 3-oxo-4,22-diene cholanoic acid-24 methyl ester. If the purification problem of the by-product triphenylphosphine is not solved, the reaction yield will be affected, and the process cannot be scaled up. (III) Summary of the invention

[0007] The invention aims to provide a highly efficient synthesis method of 3-oxo-4,22-diene cholanoic acid-24 methyl ester. The method has the advantages of mild conditions, high efficiency, simple method and the like. The purified 3-oxo-4,22-diene cholanoic acid-24 methyl ester has almost no residue in the mother liquor, and the removal rate of triphenylphosphine oxide can reach more than 98%, which plays a vital role in improving the yield of the entire preparation process.

[0008] The technical solution adopted by the present invention is:

[0009] The present invention provides a highly efficient synthesis method of 3-oxo-4,22-dienecholanoic acid-24-methyl ester, the method comprising the following steps:

[0010] (1) adding 3-oxo-4,22-diene cholanoic acid and a witing reagent to a first solvent and mixing and dissolving them until the reaction solution becomes clear; the witing reagent comprises triphenylphosphine or ethoxyformylmethylenetriphenylphosphine; and the first solvent comprises toluene or acetone;

[0011] (2) The reaction solution of step (1) is concentrated and distilled to remove the first solvent, and then a second solvent is added, a halide salt is added to form a complex precipitate with triphenylphosphine oxide, and the filter cake is obtained by filtering, and the filter cake is washed with a second solvent and dried to obtain high-purity 3-oxo-4,22-dienecholanoic acid-24-methyl ester; the second solvent includes ethanol, isopropanol, ethyl acetate or isopropyl acetate.

[0012] Furthermore, the mixed dissolution in step (1) is carried out at 60-120°C.

[0013] Furthermore, in step (1), the mass ratio of 3-oxo-4,22-diene cholanoic acid to witing reagent is 1:1-3; the volume of the first solvent added is 1-5 mL / g (preferably 3 mL / g) based on the mass of 3-oxo-4,22-diene cholanoic acid.

[0014] Furthermore, when the witing reagent is triphenylphosphine, methyl bromoacetate and / or sodium hydride are added simultaneously, and the mass ratio of the amount of methyl bromoacetate added to 3-oxo-4,22-dienocholic acid is 0.1-0.5:1 (preferably 0.36:1); the mass ratio of the amount of sodium hydride added to 3-oxo-4,22-dienocholic acid is 0.01-0.1:1 (preferably 0.09:1); triphenylphosphine and methyl bromoacetate react to generate ethoxyformylmethylenetriphenylphosphine, which can accelerate the reaction speed under the action of the strong base sodium hydride.

[0015] Furthermore, the halide salt in step (2) is one of ZnCl2 or CaBr2, and the amount of the halide salt added is 0.01-0.1:1 (preferably 0.04-0.07:1) based on the mass ratio of 3-oxo-4,22-diene cholic acid in step (1).

[0016] Furthermore, the volume of the second solvent added in step (2) is 1-5 mL / g (preferably 3 mL / g) based on the mass of 3-oxo-4,22-dienecholine acid in step (1).

[0017] Furthermore, the temperature for forming the complex precipitate in step (2) is 20-30° C. (preferably 22° C.).

[0018] Furthermore, the drying in step (2) is performed by vacuum drying at 70°C.

[0019] Furthermore, the method comprises: (1) adding 3-oxo-4,22-diene cholanic acid to a first solvent, heating from room temperature to 60-120° C., adding a witing reagent and reacting until the reaction liquid is clear; (2) removing the first solvent by evaporation and concentration, adding a halide salt and a second solvent at 22° C. to react for 3-18 hours to precipitate a complex precipitate, wherein the solubility of the complex in the second solvent is significantly lower than that of 3-oxo-4,22-diene cholanic acid-24 methyl ester, and the impurity of triphenylphosphine which is difficult to remove is effectively removed; at the same time, the solubility of 3-oxo-4,22-diene cholanic acid-24 methyl ester in the second solvent is relatively high without heating, and the 3-oxo-4,22-diene cholanic acid-24 methyl ester will not react with the halide salt, thus no precipitation or precipitation will be formed, filtering to obtain a filter cake, washing the filter cake with a second solvent, and drying to obtain high-purity 3-oxo-4,22-diene cholanic acid-24 methyl ester with a yield of 95.7%.

[0020] Chemical structures of 3-oxo-4,22-dienecholine-24-methyl ester (Ⅱ) and triphenylphosphine (Ⅲ):

[0021]

[0022] Compared with the prior art, the beneficial effects of the present invention are mainly reflected in:

[0023] The synthesis method and purification process of 3-oxo-4,22-dienecholanoic acid-24-methyl ester provided by the invention have mild conditions, simple operation and are convenient for industrial application.

[0024] The method provided by the invention is used to synthesize 3-oxo-4,22-dienecholanoic acid-24-methyl ester, with a purity of 99.6% and a yield of 95.7%. (IV) Description of the drawings

[0025] Figure 1 The figure is a schematic diagram of the reaction process for the synthesis of 3-oxo-4,22-dienecholine acid-24 methyl ester.

[0026] Figure 2 3-oxo-4,22-diene cholanoic acid-24 methyl ester prepared in Example 1 1 H NMR spectra. (V) Specific implementation methods

[0027] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:

[0028] The purity of 3-oxo-4,22-dienecholine-24-methyl ester in the embodiment of the present invention was detected by HPLC method, using a reverse phase column (C18, 4.6×250 mm, 5 μm, Waters e2695-2489, equipped with a 2489 UV / Vis detector, with a wavelength of 241 nm) at a flow rate of 1 mL / min and a column temperature of 30°C. The mobile phase consisted of acetonitrile (solvent A) and 0.1% phosphoric acid (solvent B). The gradient mode included 0 minutes, 50% B; 15 minutes, 20% B; 25 minutes, 0% B; the injection volume was set to 20 μL.

[0029] Embodiment 1:

[0030] (1) In a reaction flask, add 10 g of 3-oxo-4,22-diene cholanic acid, then add 30 mL of toluene, heat from room temperature to 60°C, add 15.4 g of triphenylphosphine, 913 mg of sodium hydride and 3.6 g of methyl bromoacetate, and react at 60°C until the reaction solution becomes clear;

[0031] (2) The reaction solution of step (1) was evaporated and concentrated to remove toluene, and 30 mL of ethanol and 0.48 g of ZnCl2 were added at 22° C. The reaction was continued for 18 h. The precipitated solid no longer increased. The filter cake was filtered to obtain a filter cake. The filter cake was washed with ethanol and dried under vacuum at 70° C. to obtain 9.57 g of 3-oxo-4,22-dienecholanoic acid-24-methyl ester. The yield was 95.7% and the purity was 99.6%. 1 H NMR diagram is attached Figure 2 .

[0032] Embodiment 2:

[0033] (1) In a reaction flask, add 10 g of 3-oxo-4,22-diene cholic acid, then add 30 mL of toluene, heat from room temperature to 80°C, add 22.1 g of ethoxycarbonylmethylenetriphenylphosphine, and react at 80°C until the reaction solution becomes clear;

[0034] (2) The reaction solution of step (1) was evaporated and concentrated to remove toluene. 30 mL of isopropanol and 0.48 g of ZnCl2 were added at 22° C. and the reaction was carried out for 18 h. When the precipitated solid no longer increased, the filter cake was obtained by filtration. The filter cake was washed with isopropanol and dried under vacuum at 70° C. to obtain 9.07 g of 3-oxo-4,22-dienecholanoic acid-24-methyl ester with a yield of 90.7% and a purity of 99.3%.

[0035] Embodiment 3:

[0036] (1) In a reaction flask, add 10 g of 3-oxo-4,22-diene cholanoic acid, then add 30 mL of acetone, heat from room temperature to 60°C, add 22.1 g of ethoxycarbonylmethylenetriphenylphosphine, and react at 60°C until the reaction solution becomes clear;

[0037] (2) The reaction solution of step (1) was evaporated and concentrated to remove acetone, and 30 mL of ethyl acetate and 0.48 g of ZnCl2 were added at 22° C. The reaction was allowed to react for 18 h. When the precipitated solid no longer increased, the filter cake was obtained by filtration. The filter cake was washed with ethyl acetate and dried under vacuum at 70° C. to obtain 8.76 g of 3-oxo-4,22-dienecholanoic acid-24-methyl ester, with a yield of 87.6% and a purity of 88.1%.

[0038] Embodiment 4:

[0039] (1) In a reaction flask, add 10 g of 3-oxo-4,22-diene cholanoic acid, then add 30 mL of toluene, heat from room temperature to 120°C, add 15.4 g of triphenylphosphine and 3.6 g of methyl bromoacetate, and react at 120°C until the reaction solution becomes clear;

[0040] (2) Step (1) The reaction solution was evaporated and concentrated to remove toluene, 30 mL of isopropyl acetate and 0.48 g of ZnCl2 were added at 22° C., and the reaction was continued for 18 h. The precipitated solid no longer increased, and the filter cake was obtained by filtration. The filter cake was washed with isopropyl acetate and dried in vacuo at 70° C. to obtain 8.76 g of 3-oxo-4,22-dienecholanoic acid-24-methyl ester, with a yield of 89.3% and a purity of 89.9%. Compared with Example 1 in which a strong base was added, both the yield and purity were reduced.

[0041] Embodiment 5:

[0042] (1) In a reaction flask, add 10 g of 3-oxo-4,22-diene cholic acid, then add 30 mL of toluene, heat from room temperature to 120°C, add 22.1 g of ethoxycarbonylmethylenetriphenylphosphine, and react at 120°C until the reaction solution becomes clear;

[0043] (2) Step (1) was concentrated by evaporation to remove toluene, and 30 mL of ethanol and 0.48 g of ZnCl2 were added at 22°C. The reaction was continued for 18 h. When the precipitated solid no longer increased, the filter cake was obtained by filtration. The filter cake was washed with ethanol and dried under vacuum at 70°C to obtain 9.38 g of 3-oxo-4,22-dienecholanoic acid-24-methyl ester, with a yield of 93.8% and a purity of 96.1%.

[0044] Embodiment 6:

[0045] (1) In a reaction flask, add 10 g of 3-oxo-4,22-diene cholic acid, then add 30 mL of toluene, heat from room temperature to 120°C, add 22.1 g of ethoxycarbonylmethylenetriphenylphosphine, and react at 120°C until the reaction solution becomes clear;

[0046] (2) Step (1) The reaction solution was evaporated and concentrated to remove toluene. 30 mL of toluene and 0.70 g of CaBr2 were added at 22° C. and the reaction was carried out for 3 h. When the precipitated solid no longer increased, the filter cake was obtained by filtration. The filter cake was washed with toluene and dried under vacuum at 70° C. to obtain 9.54 g of 3-oxo-4,22-dienecholanoic acid-24-methyl ester with a yield of 95.4% and a purity of 97.3%.

[0047] Embodiment 7:

[0048] (1) In a reaction flask, add 10 g of 3-oxo-4,22-diene cholic acid, then add 30 mL of toluene, heat from room temperature to 120°C, add 22.1 g of ethoxycarbonylmethylenetriphenylphosphine, and react at 120°C until the reaction solution becomes clear;

[0049] (2) The reaction solution of step (1) was evaporated and concentrated to remove toluene. 30 mL of tetrahydrofuran and 0.70 g of CaBr2 were added at 22° C. and reacted for 3 h. The precipitated solid no longer increased. The filter cake was filtered to obtain a filter cake. The filter cake was washed with tetrahydrofuran and dried under vacuum at 70° C. to obtain 9.29 g of 3-oxo-4,22-dienecholanoic acid-24-methyl ester. The yield was 92.9% and the purity was 94.1%.

[0050] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An efficient synthesis method of 3-oxo-4,22-diene cholanoic acid-24 methyl ester, characterized in that: The method comprises the following steps: (1) adding 3-oxo-4,22-diene cholanoic acid and a witing reagent to a first solvent and mixing and dissolving them until the reaction solution becomes clear; the witing reagent comprises triphenylphosphine or ethoxyformylmethylenetriphenylphosphine; and the first solvent comprises toluene or acetone; (2) The reaction solution of step (1) is concentrated and distilled to remove the first solvent, and then a second solvent is added, a halide salt is added to form a complex precipitate with triphenylphosphine oxide, and the filter cake is obtained by filtering, and the filter cake is washed with a second solvent and dried to obtain high-purity 3-oxo-4,22-dienecholanoic acid-24-methyl ester; the second solvent includes ethanol, isopropanol, ethyl acetate or isopropyl acetate.

2. The method according to claim 1, characterized in that The mixed dissolution in step (1) is carried out at 60-120°C.

3. The method according to claim 1, characterized in that Step (1) The mass ratio of 3-oxo-4,22-diene cholanoic acid to witing reagent is 1:1-3; the volume amount of the first solvent added is 1-5 mL / g based on the mass of 3-oxo-4,22-diene cholanoic acid.

4. The method according to claim 1, characterized in that When the witing reagent is triphenylphosphine, methyl bromoacetate and / or sodium hydride are added simultaneously, and the mass ratio of the added amount of methyl bromoacetate to 3-oxo-4,22-diene cholanic acid is 0.1-0.5:1; the mass ratio of the added amount of sodium hydride to 3-oxo-4,22-diene cholanic acid is 0.01-0.1:

1.

5. The method according to claim 1, characterized in that The halide salt in step (2) is one of ZnCl2 and CaBr2, and the amount of the halide salt added is 0.01-0.1:1 based on the mass ratio of 3-oxo-4,22-diene cholic acid in step (1).

6. The method according to claim 1, characterized in that The volume amount of the second solvent added in step (2) is 1-5 mL / g based on the mass of 3-oxo-4,22-dienecholic acid in step (1).

7. The method according to claim 1, characterized in that The temperature for forming the complex precipitate in step (2) is 20-30°C.

8. The method according to claim 1, characterized in that The drying in step (2) is performed by vacuum drying at 70°C.

9. The method according to claim 1, characterized in that The method comprises: (1) adding 3-oxo-4,22-diene cholanic acid to a first solvent, heating from room temperature to 60-120° C., adding a witing reagent, and reacting at 60-120° C. until the reaction liquid is clear; (2) removing the first solvent by evaporation and concentration, adding a halide salt and a second solvent at 22° C. to react for 3-18 hours, filtering to obtain a filter cake, washing the filter cake with a second solvent, and drying to obtain high-purity 3-oxo-4,22-diene cholanic acid-24 methyl ester.

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