A method for preparing (r)-1,2-distearoyl phosphatidylglycerol
By using allyl alcohol as a starting material, combined with a tert-butyldimethylsilane protecting group and mild reaction conditions, a low-cost, high-yield (R)-1,2-distearate phosphatidylglycerol was successfully prepared, solving the problems of difficult-to-control synthesis conditions and environmental pollution in existing technologies, making it suitable for large-scale industrial applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUZHOU SOUTHEAST PHARM CO LTD
- Filing Date
- 2023-07-12
- Publication Date
- 2026-06-12
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Figure QLYQS_1 
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of pharmaceutical and chemical technology, and specifically relates to a method for preparing artificial phospholipid distearate phosphatidylglycerol (DSPG) suitable for large-scale green industrial production. Technical Background
[0002] Phospholipids are an important component of biological membranes. Their polar phosphate ends are hydrophilic, while their two long hydrocarbon chains have nonpolar ends that are lipophilic. This unique physicochemical property allows them to spontaneously form closed bilayers in aqueous media, becoming the biological membrane framework and suitable as liposome materials in the pharmaceutical industry. (R)-1,2-distearatephosphatidylglycerol (DSPG) has advantages over natural phospholipids, including longer lifespan, better stability, and stronger antioxidant capacity.
[0003] Currently, there are few literature reports on the artificial synthesis of distearylphosphatidylglycerol, and the synthesis conditions are difficult to control, resulting in significant environmental pollution, which is not conducive to large-scale production while ensuring yield. Chinese patent document CN103864840A discloses a method for preparing artificial phospholipid DSPG, which uses 3-halopropene as a raw material for oxidation to obtain (S)-1,2-diol-3-halopropane, followed by sequential addition reactions with stearic anhydride or stearoyl halide and the introduction of a protecting phosphate group. After deprotection, (R)-1,2-glycerol distearate-glycerol-3-phosphatidic acid is obtained; finally, it undergoes an addition reaction with 2,2-dimethyl-4-methanol-1,3-dioxolane in anhydrous pyridine to obtain (R)-1,2-distearylphosphatidylglycerol (DSPG). Chinese patent document CN113354679A discloses a preparation process for sodium distearylphosphatidylglycerol (DSPGNa).
[0004]
[0005] The synthetic route involves expensive raw materials and harsh conditions, and generates a significant amount of hazardous waste, making it unsuitable for large-scale industrial production while ensuring high yields. Summary of the Invention
[0006] This invention addresses the shortcomings of existing technologies by providing a novel method for preparing (R)-1,2-distearate phosphatidylglycerol. This method features mild reaction conditions and produces fewer byproducts during the preparation of (R)-1,2-distearate phosphatidylglycerol. Compared to existing synthetic routes, it offers milder reaction conditions and is suitable for green industrial production.
[0007] The technical method of the present invention is as follows:
[0008] A method for preparing an artificial phospholipid (R)-1,2-distearate phosphatidylglycerol, characterized by comprising the following steps:
[0009] (1) Allyl alcohol and tert-butyldimethylchlorosilane react in a tetrahydrofuran solution under nitrogen protection, preferably at room temperature and stirred for 3 hours, to produce allyl tert-butyldimethylsilyl ether, as shown in the following reaction formula:
[0010]
[0011] The above reaction can be further purified by the following steps: the solution after the reaction is washed with dilute hydrochloric acid, 1.5M potassium hydroxide aqueous solution and saturated saline solution respectively, dried with anhydrous sodium sulfate, and concentrated to obtain the product.
[0012] (2) Propylene tert-butyl dimethyl silyl ether was reacted with chiral catalyst quinidine 1,4-(2,3-dioxanaphthalene) diether at 0°C under nitrogen protection in an aqueous tert-butanol solution with stirring for 5 hours, preferably with a volume ratio of tert-butanol to water of 2:1, to obtain (S)-1,2-diol-3-tert-butyl dimethyl silyl propyl ether, as shown in the following reaction formula:
[0013]
[0014] The preferred oxidant for the above reaction is K2OsO2(OH)4.
[0015] The above reaction may further include a purification step: the aqueous layer of the reaction product is separated and extracted with ethyl acetate; the combined organic layers are washed with 1M potassium hydroxide solution, dilute hydrochloric acid, and saturated brine, respectively. Anhydrous magnesium sulfate is dried and concentrated to obtain a crude product, which is then recrystallized from a mixture of petroleum ether and ethyl acetate to obtain a pure product.
[0016] (3) Reaction of (S)-1,2,-diol-3-tert-butyldimethylsilyl ether with a hard acyl halide in dichloromethane under nitrogen protection, preferably refluxed at 40°C for 4 hours, yields (R)-1,2-distearate-3-tert-butyldimethylsilylpropyl ether, as shown in the following reaction formula:
[0017]
[0018] Where Y is a halogen, representing Cl, Br, or I, with Cl being preferred; R represents a straight-chain alkane C. 17 H 35 .
[0019] The above reaction may further include a purification step: after cooling the reaction system to room temperature, a large amount of anhydrous diethyl ether is poured in. The organic layer is washed with 10% sodium bicarbonate aqueous solution and saturated brine, dried with anhydrous sodium sulfate, filtered, and the crude product obtained by concentration under reduced pressure is recrystallized with methyl tert-butyl ether.
[0020] (4) The silane protecting group of (R)-1,2-distearate-3-tert-butyldimethylsilylpropyl ether is removed by stirring at room temperature for 10 hours in a mixed solution of acetic acid, tetrahydrofuran, and water, preferably acetic acid, with a volume ratio of tetrahydrofuran to water of 3:1:1, to obtain (R)-1,2-distearate-3-propanol. The reaction formula is as follows:
[0021]
[0022] Where R represents a straight-chain alkane C. 17 H 35 .
[0023] The above reaction may further include a purification step: washing the reaction product with saturated brine, drying it with anhydrous sodium sulfate, and concentrating it to obtain the final product.
[0024] (5) Sodium (R)-1,2-distearate-3-propanol tert-butoxide is stirred in dichloromethane, preferably under nitrogen protection, at room temperature for 30 minutes. Then, diethyl chlorophosphate, preferably diluted tenfold with dichloromethane, is added to the reaction system. The mixture is stirred at room temperature for 10 hours to produce diethyl (R)-1,2-distearate-3-phospholipid, as shown in the following reaction formula:
[0025]
[0026] Where R represents a straight-chain alkane C. 17 H 35 .
[0027] (6) Trimethylbromosilane is preferably diluted ten times with anhydrous dichloromethane at 0°C. A dichloromethane solution of (R)-1,2-distearate-3-phosphatidylcholine is stirred at room temperature for 3 hours under nitrogen protection to produce (R)-1,2-distearate-3-phosphatidylcholine, as shown in the following reaction formula:
[0028]
[0029] Where R represents a straight-chain alkane C. 17 H 35 .
[0030] The above reaction may further include a purification step: after the reaction is complete, the reaction is quenched with methanol at 0°C, the crude product is concentrated, dissolved by heating with ethyl acetate, and crystallized with petroleum ether to obtain the product.
[0031] (7) Dissolve (R)-1,2-distearate-3-phosphatidic acid and (R)-p-toluenesulfonic acid glycidyl ester in dichloromethane, preferably under nitrogen protection at room temperature for 4 hours under conditions of pH 5-7, to produce (R)-1,2-distearate phosphatidylglycerol, as shown in the following reaction formula:
[0032]
[0033] Where R represents a straight-chain alkane C. 17 H 35 .
[0034] The preparation method of the present invention includes a step of recrystallizing the (R)-1,2-distearatephosphatidylglycerol obtained in step (7). Ethyl acetate is preferred as the recrystallization solvent.
[0035] Alternatively, the (R)-1,2-distearatephosphatidylglycerol obtained in step (7) can be purified by concentrating the reaction product under reduced pressure to obtain a crude product, followed by rapid column chromatography (200-300 mesh, developing solvent CHCl3:CH3OH:H2O=15:3:1, v / v / v) to obtain a white gel.
[0036] Compared with existing preparation methods, the present invention has the following advantages:
[0037] 1. The synthesis of (R)-1,2-distearate phosphatidylglycerol from simple raw materials has a lower cost; the selected hydroxyl protecting group TBS group is environmentally friendly and easier to remove in industrial production; trimethylbromosilane has high coupling efficiency with hydroxyl groups, which improves the yield; compared with other synthetic routes, most of the reaction temperature in this route is at room temperature, which reduces energy consumption costs in industry.
[0038] 2. The synthesized (R)-1,2-distearate phosphatidylglycerol exhibits good optical stability, ensuring the optical purity of subsequent products.
[0039] 3. This invention uses allyl alcohol as the starting material, and the tert-butyldimethylsilyl protecting group used is easy to remove. The other raw materials used are readily available, the reaction conditions are mild and easy to introduce, and it is more suitable for industrial production and application. Detailed Implementation
[0040] The specific process steps described below are illustrated by way of embodiments. However, these embodiments do not limit the present invention, and any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the scope of protection of the present invention.
[0041] Unless otherwise stated, the terms used in this invention generally have the meanings commonly understood by those skilled in the art.
[0042] Example 1. Preparation of tert-butyl dimethyl silyl ether.
[0043] Under nitrogen protection, 58 g (1 mol) of allyl alcohol and 180 g (1.2 mol) of tert-butyldimethylchlorosilane were dissolved in 1 L of dichloromethane and stirred at room temperature for 3 h. The resulting solution was washed with 1 M dilute hydrochloric acid, 1.5 M potassium hydroxide aqueous solution and saturated brine, dried over anhydrous sodium sulfate and concentrated to obtain 170 g of tert-butyldimethylsilyl ether, with a yield of 98%.
[0044] Example 2. Preparation of (S)-1,2-diol-3-tert-butyldimethylsilylpropyl ether.
[0045] Under nitrogen protection, 80 g (1 mol) of 1,4-(2,3-diazanaphthalene diether)(DHQD)2PHAL and 180 g (0.5 mol) of K2OsO2(OH)4 were added to a round-bottom reaction flask and dissolved in 1 L of an aqueous solution of tert-butanol (tert-butanol:water = 2:1). The mixture was stirred at 0 °C for 30 minutes, and then 0.17 g (0.99 mmol) of propylene tert-butyldimethylsilyl ether was added and the reaction was carried out for 5 hours. Finally, 200 g of Na2S2O4 was added and the reaction was stopped by stirring for another 30 minutes. The aqueous layer of the reaction product was separated and extracted with ethyl acetate. The combined organic layers were washed with 1 M potassium hydroxide aqueous solution, 1 N dilute hydrochloric acid, and saturated brine, respectively. The product was dried over anhydrous magnesium sulfate and concentrated to obtain a crude product. Recrystallization was performed using a mixture of petroleum ether and ethyl acetate to obtain 150 g of (S)-1,2-diol-3-tert-butyldimethylsilylpropyl ether, with a yield of 75%.
[0046] Example 3. Preparation of (R)-1,2-distearate-3-tert-butyldimethylsilylpropyl ether.
[0047] 23 g (0.75 mol) of stearoyl chloride and 10 g (0.5 mol) of (S)-1,2-diol-3-tert-butyldimethylsilylpropyl ether were dissolved in 200 mL of dichloromethane. The mixture was refluxed at 40 °C for 4 hours under nitrogen protection. Heating was then stopped, and the reaction system was cooled to room temperature. A large amount of anhydrous diethyl ether was then added. The organic layer was washed with 100 mL of 10% sodium bicarbonate aqueous solution and saturated brine, dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was recrystallized from methyl tert-butyl ether to give 29 g of (R)-1,2-distearate-3-tert-butyldimethylsilylpropyl ether, with a yield of 81%.
[0048] Example 4. Preparation of (R)-1,2-distearate-3-propanol.
[0049] 22 g (0.3 mol) of (R)-1,2-distearate-3-tert-butyldimethylsilylpropyl ether was dissolved in 15 mL of a mixed solution of acetic acid:tetrahydrofuran:water = 3:1:1 (v / v / v). The mixture was stirred at room temperature for 10 hours under nitrogen protection. The reaction product was washed with saturated brine, dried over anhydrous sodium sulfate, and concentrated to give 16 g of (R)-1,2-distearate-3-propanol, with a yield of 85%.
[0050] Example 5. Preparation of (R)-1,2-distearate-3-phospholipid diethyl ester.
[0051] 0.16 g (0.25 mmol) of (R)-1,2-distearate-3-propanol and 2.4 g (0.25 mol) of sodium tert-butoxide were stirred in dichloromethane at room temperature for 30 minutes under nitrogen protection. 5.2 g (0.3 mol) of diluted diethyl chlorophosphate was added to the reaction system after dilution with 2 mL of dichloromethane. The mixture was stirred at room temperature for 10 hours. The product was washed with saturated brine, and the organic layer was dried over anhydrous sodium sulfate. The product was concentrated to give 0.14 g of (R)-1,2-distearate-3-phospholipid diethyl ester, with a yield of 73%.
[0052] Example 6. Preparation of (R)-1,2-distearate-3-phosphatidic acid.
[0053] 10 g (0.13 mol) of (R)-1,2-distearate-3-propanol was dissolved in 100 mL of anhydrous dichloromethane. 2 g (0.26 mol) of trimethylbromosilane was diluted in 200 mL of anhydrous dichloromethane at 0 °C. The mixture was stirred at room temperature for 3 hours under nitrogen protection. After the reaction was complete, the reaction was quenched with 100 mL of methanol at 0 °C. The crude product was concentrated and dissolved in 5 mL of ethyl acetate by heating. The solution was then crystallized from 4 mL of petroleum ether to give 8.4 g of a white solid (R)-1,2-distearate-3-phosphatidic acid, with a yield of 92%.
[0054] Example 7. Preparation of (R)-1,2-distearate phosphatidylglycerol.
[0055] 7 g (0.1 mol) (R)-1,2-distearate-3-phosphatidic acid and 2 g (0.1 mol) (R)-p-toluenesulfonic acid glycidyl ester were dissolved in dichloromethane. The solution was adjusted to pH 5-7 with dilute hydrochloric acid and stirred at room temperature for 4 hours under nitrogen protection. The reaction product was concentrated under reduced pressure to obtain a crude product, which was recrystallized from ethyl acetate to give 4.3 g of a white gel, with a yield of 57%.
[0056] Example 8. Effect of the amount of ethyl acetate used for recrystallization of (R)-1,2-distearate phosphatidylglycerol on the yield.
[0057] 10 g of crude (R)-1,2-distearate phosphatidylglycerol was added to a round-bottom flask, and 10 mL, 15 mL, 20 mL, 25 mL, and 30 mL of ethyl acetate were added respectively. The yields were calculated, and the results are shown in the table below:
[0058] Ethyl acetate volume (mL) Yield (%) 10 31.1％ 15 45.5％ 20 57.0％ 25 49.4％ 30 33.3％
[0059] Therefore, in the preparation of (R)-1,2-distearate phosphatidylglycerol, it is preferable that the volume of ethyl acetate used during recrystallization is twice that of the crude product.
[0060] Example 9. Effect of the volume ratio of tert-butanol to water in step (2) on the yield of product (S)-1,2-diol-3-tert-butyldimethylsilylpropyl ether
[0061] Under nitrogen protection, 8 g (0.1 mol) of quinidine 1,4-(2,3-diazanaphthalene diether)(DHQD)2PHAL and 18 g (0.05 mol) of K2OsO2(OH)4 were added to a round-bottom reaction flask. The mixture was dissolved in 100 mL of aqueous solutions of tert-butanol in varying proportions. The mixture was stirred at 0°C for 30 minutes. Then, 0.017 g (0.1 mol) of propylene tert-butyl dimethyl silyl ether was added, and the reaction was continued for 5 hours. Finally, 20 g of Na2S2O4 was added, and the reaction was stopped after stirring for another 30 minutes. The aqueous layer of the reaction product was separated and extracted with ethyl acetate. The combined organic layers were washed with 1M potassium hydroxide solution, 1N dilute hydrochloric acid, and saturated brine, respectively. The crude product was dried over anhydrous magnesium sulfate and concentrated. Recrystallization was performed using a mixture of petroleum ether and ethyl acetate. The yields were calculated after filtration, and the results are shown in the table below.
[0062] tert-Butanol:Water (v / v) Yield (%) 1:1 39.1％ 1:2 9.6％ 1:3 2.1％ 2:1 74.7％ 3:1 42％
[0063] Therefore, in the preparation of (S)-1,2-diol-3-tert-butyldimethylsilylpropyl ether, the volume ratio of tert-butanol to water in the aqueous solution of tert-butanol is preferably 2:1.
[0064] Example 9. Effect of the volume ratio of the mixed solvents acetic acid, tetrahydrofuran, and water in step (4) on the yield of product (R)-1,2-distearate-3-propanol
[0065] 20 g (0.3 mol) of (R)-1,2-distearate-3-tert-butyldimethylsilylpropyl ether was dissolved in 15 mL of a mixed solution of acetic acid, tetrahydrofuran, and water in different volume ratios. The mixture was stirred at room temperature for 10 hours under nitrogen protection. The reaction product was washed with saturated brine, dried over anhydrous sodium sulfate, concentrated, and the yields were calculated. The results are shown in the table below.
[0066] Acetic acid:tetrahydrofuran:water (v / v / v) Yield (%) 1:1:1 44.4％ 1:1:2 37.1％ 1:1:3 26.8％ 2:1:1 67.5％ 3:1:1 83.9％
[0067] Therefore, the preferred volume ratio of the mixed solvents acetic acid, tetrahydrofuran, and water in the preparation of (R)-1,2-distearate-3-propanol is 3:1:1.
Claims
1. A method for preparing (R)-1,2-distearate phosphatidylglycerol, characterized by the following steps: (1) Allyl alcohol reacts with tert-butyldimethylchlorosilane in tetrahydrofuran solution under nitrogen protection at room temperature to produce tert-butyldimethylsilyl ether, as shown in the following reaction formula: ； (2) Propylene tert-butyl dimethyl silyl ether undergoes oxidation in an aqueous tert-butanol solution under nitrogen protection at 0°C, catalyzed by the chiral catalyst hydrogenated quinidine 1,4-(2,3-dioxanaphthalene) diether, to give (S)-1,2-diol-3-tert-butyl dimethyl silyl ether propane, as shown in the following reaction formula: ； (3) The reaction of (S)-1,2-diol-3-tert-butyldimethylsilyl ether with stearoyl halide under nitrogen protection in dichloromethane yields (R)-1,2-distearate-3-tert-butyldimethylsilylpropyl ether, as shown in the following reaction formula: ， Where Y is a halogen, representing Cl, Br, or I, and R represents a straight-chain alkane C. 17 H 35 ; (4) The silane protecting group of (R)-1,2-distearate-3-tert-butyldimethylsilyl ether propane was removed by stirring at room temperature in a mixed solution of acetic acid, tetrahydrofuran and water to obtain (R)-1,2-distearate-3-propanol, as shown in the following reaction formula: ， Where R represents a straight-chain alkane C. 17 H 35 ; (5) (R)-1,2-distearate-3-propanol is reacted with diethyl chlorophosphate and sodium tert-butoxide in dichloromethane under nitrogen protection at room temperature to produce (R)-1,2-distearate-3-phospholipid diethyl ester. The reaction formula is as follows: ， Where R represents a straight-chain alkane C. 17 H 35 ; (6) (R)-1,2-distearate-3-phosphatidyl diethyl ester and trimethylbromosilane were stirred in dichloromethane at room temperature under nitrogen protection to produce (R)-1,2-distearate-3-phosphatidyl acid. The reaction formula is as follows: ， Where R represents a straight-chain alkane C. 17 H 35 ; (7) (R)-1,2-distearate-3-phosphatidic acid and (R)-p-toluenesulfonic acid glycidyl ester dichloromethane were stirred at room temperature under nitrogen protection to produce (R)-1,2-distearate-phosphatidylglycerol, and the reaction formula is as follows: ， Where R represents a straight-chain alkane C. 17 H 35 .
2. The preparation method according to claim 1, characterized in that... The oxidant used in step (2) oxidation reaction is K2OsO2(OH)4.
3. The preparation method according to claim 1, characterized in that... In step (2), the volume ratio of tert-butanol to water in the aqueous solution of tert-butanol is 1:
2.
4. The preparation method according to claim 1, characterized in that... The volume ratio of acetic acid, tetrahydrofuran and water in step (4) is 3:1:
1.
5. The preparation method according to any one of claims 1-4, characterized in that... It also includes a step of recrystallizing the (R)-1,2-distearatephosphatidylglycerol obtained in step (7) using ethyl acetate.