Preparation method of ursodesoxycholic acid
Through a simple and efficient process, including esterification, oxidation and reduction reaction, the problems of excessive synthesis route, low safety and low yield in the existing synthetic ursodeoxycholic acid method have been successfully solved, achieving high efficiency, Safe ursodeoxycholic acid synthesis, suitable for industrial production.
Patent Information
- Application Number
- CN202411573606.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-06
- Publication Date
- 2025-02-18
AI Technical Summary
The existing methods for synthesizing ursodeoxycholic acid have problems such as too long synthesis route, low safety and low yield, and industrial production cannot be achieved.
Through a simple and efficient process, including esterification of gestinocholic acid in the presence of methanol and catalyst, followed by esterification with acetic anhydride in an organic solvent, adjusting the pH value, oxidation and reduction reactions, Ursodeoxycholic acid is finally obtained in the presence of n-butanol and reducing agent.
The synthesis steps are simplified, the safety is improved, and the yield is improved, making it suitable for industrial production.
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Abstract
Description
Technical Field
[0001] The invention relates to a method for preparing ursodeoxycholic acid under low cost and mild reaction conditions, and belongs to the technical field of organic synthesis. Background Art
[0002] Ursodeoxycholic acid (3α, 7β-dihydroxy-5β-cholanoic acid) is the main component of bear bile in traditional Chinese medicine. It was once mainly used to treat gallstones, digestive tract diseases and various acute and chronic liver diseases. New research shows that ursodeoxycholic acid not only has a good effect on the treatment of primary biliary cirrhosis, primary sclerosing cholangitis, and chronic active hepatitis, but can also be used to treat chronic hepatitis and rejection after liver transplantation.
[0003] The chemical method for synthesizing ursodeoxycholic acid that has been reported mainly extracts and separates bile acid, hyodeoxycholic acid, and chenodeoxycholic acid from the bile of cattle, sheep, pigs, chickens, and ducks, and then converts them into ursodeoxycholic acid through multi-step reactions. The synthesis route and process of ursodeoxycholic acid synthesized from bile acid and hyodeoxycholic acid as starting materials are extremely complicated, with an average of about 7 steps of synthesis steps, low yield, and inability to achieve industrial production. Chenodeoxycholic acid and ursodeoxycholic acid are diastereomers of each other, and the process of synthesizing ursodeoxycholic acid from chenodeoxycholic acid is relatively simple, but the current synthesis method is still relatively complicated, with low safety and low yield.
[0004] In view of the problems existing in the existing process of synthesizing ursodeoxycholic acid, such as a long synthesis route, low safety, and low yield, the present invention is intended to provide a new process for synthesizing ursodeoxycholic acid. Summary of the invention
[0005] In view of the deficiencies in the prior art, the present invention provides a method for preparing ursodeoxycholic acid, which has simple and efficient synthesis process, high safety and high product purity.
[0006] The preparation method of ursodeoxycholic acid provided by the present invention comprises the following steps:
[0007] S1. In the presence of methanol and catalyst I, chenodeoxycholic acid is subjected to esterification reaction, and then an excess of base is added, filtered and concentrated to obtain compound 2;
[0008] S2. In an organic solvent I, the compound 2 is subjected to an esterification reaction with acetic anhydride, and then the pH value is adjusted to acidic, and the compound 3 is obtained by extraction, concentration and purification;
[0009] S3, in an organic solvent II, in the presence of a catalyst II, the compound 3 is subjected to an oxidation reaction, and then extracted, concentrated, and purified to obtain a compound 4;
[0010] S4. In the presence of n-butanol and a reducing agent, the compound 4 is subjected to a reduction reaction, and then an excess of hydrochloric acid is added, extracted, concentrated, and purified to obtain ursodeoxycholic acid.
[0011] The synthetic process route of the preparation method of the present invention is as follows:
[0012]
[0013] In the preparation method of the present invention, in step S1, the catalyst I is one of p-toluenesulfonic acid, dilute sulfuric acid, dilute hydrochloric acid, benzenesulfonic acid and methanesulfonic acid,
[0014] The alkali is one of sodium hydroxide, sodium carbonate and sodium bicarbonate;
[0015] The molar ratio of the chenodeoxycholic acid to the catalyst I is 1:0.05-0.5, the reaction temperature is 10-35°C, and the stirring time is 2-6h.
[0016] In the preparation method of the present invention, in step S2, the organic solvent I is one of pyridine, triethylamine and piperidine;
[0017] The molar ratio of the compound 2, the acetic anhydride and the organic solvent I is 1:2-4:5-15, the reaction temperature is 10-35° C., the stirring time is 10-15 h, and the pH is 4-6.
[0018] In the preparation method of the present invention, in step S3, the organic solvent II is one of acetone, ethyl acetate and tetrahydrofuran;
[0019] The catalyst II is one of NBS, sodium periodate, potassium permanganate, potassium dichromate and chromium trioxide;
[0020] The molar ratio of the compound 3 to the catalyst II is 1:1-3, the stirring temperature is 10-35°C, and the reaction time is 10-15h.
[0021] In the preparation method of the present invention, in step S4, the reducing agent is one of metallic sodium, nickel dichloride, and metallic lithium;
[0022] The molar ratio of the compound 4 to the reducing agent is 1:10-40, the stirring temperature is 80-120° C., and the reaction time is 1-5 h.
[0023] In the preparation method of the present invention, in steps S2-S4, the purification steps are all silica gel column chromatography.
[0024] Compared with the prior art, the preparation method of the present invention has the following characteristics:
[0025] 1) The method of the present invention has short synthesis steps, simple operation and high yield.
[0026] 2) The method of the present invention has low energy consumption and low cost.
[0027] 3) The method of the present invention is highly safe and easy to produce on an industrial scale. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of compound 2 provided by the present invention.
[0029] Figure 2 The hydrogen nuclear magnetic resonance spectrum of compound 3 provided by the present invention.
[0030] Figure 3 The hydrogen nuclear magnetic resonance spectrum of compound 4 provided by the present invention.
[0031] Figure 4 The hydrogen nuclear magnetic resonance spectrum of compound 5 provided by the present invention. DETAILED DESCRIPTION
[0032] The present invention is further described below in conjunction with specific examples, but the present invention is not limited to the following examples. The methods described are conventional methods unless otherwise specified. The raw materials described can be obtained from public commercial channels unless otherwise specified.
[0033] The specifications and sources of the reagents used in the following examples are as follows:
[0034] Chenodeoxycholic acid, acetic anhydride, p-toluenesulfonic acid, methanesulfonic acid, pyridine, triethylamine, acetone, NBS, sodium periodate, metallic sodium, nickel dichloride, metallic lithium, hydrochloric acid, and sodium hydroxide were all purchased from Shanghai Sinopharm Chemical Reagent Co., Ltd. and were all analytically pure reagents.
[0035] Embodiment 1,
[0036] (1) Add 20 g of chenodeoxycholic acid (Compound 1) and 0.49 g of methanesulfonic acid to methanol, react at 28° C. for 6 h, add excess sodium carbonate, filter, and concentrate to obtain Compound 2 with a yield of 98%.
[0037] Among them, the nuclear magnetic resonance hydrogen spectrum of compound 2 is as follows Figure 1 As shown, it can be seen that compound 2 is methyl esterified chenodeoxycholic acid.
[0038] (2) 10 g of compound 2 was dissolved in pyridine, 7.7 g of acetic anhydride was added, and the reaction system was stirred at 28° C. for 10 h. After the reaction, the pH of the system was adjusted to 5-6 with dilute hydrochloric acid, extracted, concentrated, and purified by silica gel column chromatography (petroleum ether / ethyl acetate=5:2) to obtain compound 3 with a yield of 85%.
[0039] Among them, the nuclear magnetic resonance hydrogen spectrum of compound 3 is as follows Figure 2As shown, it can be seen that compound 3 is methyl chenodeoxycholate in which the hydroxyl group at the carbon atom position 3 is protected by acetylation.
[0040] (3) 1 g of compound 3 was dissolved in acetone, 0.7 g of NBS was added, and the mixture was stirred at 28° C. for 10 h. The mixture was extracted, concentrated, and chromatographed on a silica gel column (petroleum ether / ethyl acetate=1:3) to obtain compound 4 with a yield of 90%.
[0041] Among them, the nuclear magnetic resonance hydrogen spectrum of compound 4 is as follows Figure 3 As shown, it can be seen that compound 4 is methyl chenodeoxycholate in which the hydroxyl group on the carbon atom at position 7 is oxidized to a keto group, and the hydroxyl group on the carbon atom at position 3 is protected by acetylation.
[0042] (4) 10 g of compound 4 was dissolved in n-butanol, 18 g of sodium metal was added, and the mixture was stirred at 100° C. for 3 h. An excess of hydrochloric acid was added, and the mixture was extracted, concentrated, and chromatographed on a silica gel column (petroleum ether / ethyl acetate=5:2) to obtain the target product ursodeoxycholic acid (compound 5) with a yield of 95%.
[0043] Among them, the nuclear magnetic resonance hydrogen spectrum of compound 5 (ursodeoxycholic acid) is as follows Figure 4 As shown, it can be seen that compound 5 is ursodeoxycholic acid, and the configuration of the hydroxyl group at position 7 of the compound 5 is opposite to that of the hydroxyl group at position 7 of chenodeoxycholic acid.
[0044] The total yield of this example is 71%.
[0045] Embodiment 2,
[0046] (1) Add 20 g of chenodeoxycholic acid (Compound 1) and 0.80 g of benzenesulfonic acid to methanol, react at 28° C. for 6 h, add excess sodium carbonate, filter, and concentrate to obtain Compound 2 with a yield of 97%.
[0047] (2) 10 g of compound 2 was dissolved in pyridine, 7.7 g of acetic anhydride was added, and the reaction system was stirred at 35° C. for 8 h. After the reaction was completed, the pH of the system was adjusted to 5-6 with dilute hydrochloric acid, extracted, concentrated, and purified by silica gel column chromatography to obtain compound 3 with a yield of 82%.
[0048] (3) 1 g of compound 3 was dissolved in acetone, 1.6 g of sodium periodate was added, and the mixture was stirred at 28°C for 10 h. The mixture was extracted, concentrated, and subjected to silica gel column chromatography to obtain compound 4 with a yield of 91%.
[0049] (4) 10 g of compound 4 was dissolved in n-butanol, 32 g of nickel dichloride was added, and the mixture was stirred at 100° C. for 3 h. Excess hydrochloric acid was added, and the mixture was extracted, concentrated, and subjected to silica gel column chromatography to obtain the target product ursodeoxycholic acid (compound 5) with a yield of 94%.
[0050] The total yield of this example is 68%.
[0051] Comparative Example 1
[0052] (1) Add 20 g of chenodeoxycholic acid and 0.8 g of hydrochloric acid to methanol, react at 80° C. for 10 h, add excess sodium bicarbonate, extract, concentrate, and purify by silica gel column chromatography (petroleum ether / ethyl acetate=5:2) to obtain methyl esterified chenodeoxycholic acid with a yield of 91%.
[0053] (2) Dissolve 10 g of chenodeoxycholic acid methyl ester in pyridine, add 8 g of ethyl chloroformate, and stir the reaction system at 0°C for 12 h. After the reaction, adjust the pH of the system to 5-6 with dilute hydrochloric acid, extract, concentrate, and purify by silica gel column chromatography (petroleum ether / ethyl acetate = 3:1) to obtain 3-protected chenodeoxycholic acid methyl ester with a yield of 88%.
[0054] (3) 1 g of 3-position protected chenodeoxycholic acid methyl ester was dissolved in acetone, 0.7 g of Jones reagent was added, and the mixture was stirred at 0°C for 10 h. The mixture was extracted, concentrated, and chromatographed on a silica gel column (petroleum ether / ethyl acetate = 5:2) to obtain a chenodeoxycholic acid derivative in which the 7-position hydroxyl group was oxidized to a carbon group. The yield was 94%.
[0055] (4) Dissolve 10 g of a chenodeoxycholic acid derivative in which the 7-hydroxyl group is oxidized to a carbon group in water, add 15 g of potassium hydroxide, stir at 100° C. for 3 h, add excess hydrochloric acid, extract, concentrate, and perform silica gel column chromatography (petroleum ether / ethyl acetate=5:2) to obtain chenodeoxycholic acid in which the 7-hydroxyl group is oxidized to a carbon group, with a yield of 83%.
[0056] (5) 30 g of sodium borohydride and 50 g of chenodeoxycholic acid in which the 7-hydroxyl group is oxidized to a carbon group are dissolved in 50 mL of tetrahydrofuran and stirred at 0°C for 3 h. After the reaction is completed, the reaction solution is acidified with a 20% hydrochloric acid solution, the tetrahydrofuran is evaporated, and then poured into water, extracted with ethyl acetate, washed twice with a saturated sodium chloride solution, dried, and then the solvent is removed to obtain ursodeoxycholic acid with a yield of 91%.
[0057]
[0058] The results showed that the process included five steps of reaction and the route was too long. Although the yield of each step was high, the overall yield was not high (57%). Each step of the reaction required cooling or heating, and the explosive reagent sodium borohydride was used, which had high energy consumption, low safety and high cost.
[0059] Comparative Example 2
[0060] (1) Dissolve 6 g of chenodeoxycholic acid in a mixed solution of 160 mL of acetone and water (3:1), then add 3.26 g of NBS and keep in a constant temperature water bath at 26°C for 1 hour. After the reaction is complete, add an excess of sodium bisulfite solution and pour into a large amount of water to precipitate white flocs, which are filtered and washed with distilled water until neutral to obtain a white solid, which is chenodeoxycholic acid with the 7-hydroxy group oxidized to a carbon group, with a yield of 30%.
[0061] (2) 5 g of chenodeoxycholic acid in which the 7-hydroxyl group is oxidized to a carbon group and 3.82 g of CeCl3·7H2O are placed in a flask, 100 mL of n-butanol is added, and the mixture is heated to reflux. After dissolution, the mixture is cooled to room temperature, and 2.42 g of potassium borohydride is added, and the mixture is stirred for 3 h. The solvent is evaporated to dryness, and the obtained light yellow solid is dissolved in sodium carbonate solution, filtered, and hydrochloric acid is added to the filtrate to acidify it, and white floccules are precipitated. The mixture is filtered, washed with water, dried, and recrystallized to obtain ursodeoxycholic acid, with a yield of 88%.
[0062]
[0063] The results showed that although the process was simple, the oxidation reaction in step (1) was not selective, and both the 3- and 7-hydroxyl groups of chenodeoxycholic acid could be oxidized, resulting in a low yield of the target product (total yield 26%) and a large amount of impurities. In step (2), an explosive reagent, potassium borohydride, was used, which had low safety and was not convenient for industrial production.
[0064] Comparative Example 3
[0065] (1) Add 20 g of chenodeoxycholic acid (Compound 1) and 0.49 g of methanesulfonic acid to methanol, react at 28° C. for 6 h, add excess sodium carbonate, filter, and concentrate to obtain Compound 2 with a yield of 98%.
[0066] (2) 10 g of compound 2 was dissolved in pyridine, 7.7 g of acetic anhydride was added, and the reaction system was stirred at 28° C. for 10 h. After the reaction, the pH of the system was adjusted to 5-6 with dilute hydrochloric acid, extracted, concentrated, and purified by silica gel column chromatography (petroleum ether / ethyl acetate=3:1) to obtain compound 3 with a yield of 85%.
[0067] (3) 1 g of compound 3 was dissolved in acetone, 0.7 g of NBS was added, and the mixture was stirred at 28° C. for 10 h. The mixture was extracted, concentrated, and chromatographed on a silica gel column (petroleum ether / ethyl acetate=5:2) to obtain compound 4 with a yield of 90%.
[0068] (4) 10 g of compound 4 was dissolved in n-butanol, 18 g of sodium metal was added, and the mixture was stirred at 50° C. for 6 h. Excess hydrochloric acid was added, and the mixture was extracted, concentrated, and chromatographed on a silica gel column (petroleum ether / ethyl acetate=5:2) to obtain the target product ursodeoxycholic acid (compound 5) with a yield of 15%.
[0069] The results showed that the total yield was 11%. The reaction in step (4) could simultaneously remove the carboxyl and hydroxyl protection groups, but too low a reaction temperature would result in the failure of the deprotection.
[0070] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.
Claims
1. A method for preparing ursodeoxycholic acid, comprising the following steps: S1. In the presence of methanol and catalyst I, chenodeoxycholic acid is subjected to esterification reaction, and then an excess of base is added, filtered and concentrated to obtain compound 2; S2. In an organic solvent I, the compound 2 is subjected to an esterification reaction with acetic anhydride, and then the pH value is adjusted to acidic, and the compound 3 is obtained by extraction, concentration and purification; S3, in an organic solvent II, in the presence of a catalyst II, the compound 3 undergoes an oxidation reaction, and then is extracted, concentrated, and purified to obtain a compound 4; S4. In the presence of n-butanol and a reducing agent, the compound 4 is subjected to a reduction reaction, and then an excess of hydrochloric acid is added, extracted, concentrated, and purified to obtain ursodeoxycholic acid.
2. The preparation method according to claim 1, characterized in that: In step S1, the catalyst I is one of p-toluenesulfonic acid, dilute sulfuric acid, dilute hydrochloric acid, benzenesulfonic acid and methanesulfonic acid. The alkali is one of sodium hydroxide, sodium carbonate and sodium bicarbonate; The molar ratio of the chenodeoxycholic acid to the catalyst I is 1:0.05-0.5, the reaction temperature is 10-35°C, and the stirring time is 2-6h.
3. The preparation method according to claim 1 or 2, characterized in that: In step S2, the organic solvent I is one of pyridine, triethylamine and piperidine; The molar ratio of the compound 2, the acetic anhydride and the organic solvent I is 1:2-4:5-15, the reaction temperature is 10-35° C., the stirring time is 10-15 h, and the pH is 4-6.
4. The preparation method according to any one of claims 1 to 3, characterized in that: In step S3, the organic solvent II is one of acetone, ethyl acetate and tetrahydrofuran; The catalyst II is one of NBS, sodium periodate, potassium permanganate, potassium dichromate, and chromium trioxide; The molar ratio of the compound 3 to the catalyst II is 1:1-3, the stirring temperature is 10-35°C, and the reaction time is 10-15h.
5. The preparation method according to any one of claims 1 to 4, characterized in that: In step S4, the reducing agent is one of metallic sodium, nickel dichloride, and metallic lithium; The molar ratio of the compound 4 to the reducing agent is 1:10-40, the stirring temperature is 80-120° C., and the reaction time is 1-5 h.
6. The preparation method according to any one of claims 1 to 5, characterized in that: In steps S2-S4, the purification steps are all performed by silica gel column chromatography.