Preparation method of medicinal pregnenolone isobutyrate

Abstract

The invention discloses a preparation method of medicinal pregnenolone isobutyrate, which comprises the following steps: (1) sequentially adding isobutyric acid (I), an organic solvent A and an acid-binding agent into a reaction container, uniformly stirring, dropwise adding an organic solvent A solution of an organic phosphorus condensing agent, and reacting to obtain a reaction solution containing an intermediate (II); (2) dropwise adding a pregnenolone (III) solution into the reaction solution, and reacting to obtain a reaction solution containing pregnenolone isobutyrate (IV); (3) filtering the reaction solution obtained in the step (2), concentrating under reduced pressure, dissolving, passing through a silica gel column, eluting with normal hexane / ethyl acetate, dripping a TLC plate, collecting eluent containing pregnenolone isobutyrate, and concentrating under reduced pressure to obtain concentrated solution; (4) adding an organic solvent B, uniformly stirring, and filtering to obtain a filter cake; (5) washing a filter cake, and drying to obtain medicinal pregnenolone isobutyrate (IV); the method has the advantages of high safety, easily available raw materials, low production cost, high yield and small environmental pollution.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of pharmacy, and particularly relates to a preparation method of pharmaceutical pregnenolone isobutyrate. BACKGROUND

[0002] Pregnenolone isobutyrate is an esterified pregnenolone derivative formed by esterification of endogenous hormone precursor pregnenolone and isobutyrate. Pregnenolone derivative is a "pro-athletic supplement" that can improve endurance or recovery ability, and pregnenolone isobutyrate can play a potential role by regulating steroid hormone metabolism and neural activity. Its action is mainly based on the physiological function of pregnenolone, the pharmacokinetic optimization of the esterified structure and the use as a standard for drug detection.

[0003] The patent for invention with Chinese patent number CN201310379872 discloses a preparation method of pregnenolone acetate similar to pregnenolone isobutyrate, i.e. using ethyl acetate as a solvent, palladium / carbon catalyst and ammonium acetate as a composite catalyst to hydrogenate dienolone acetate. The method is hydrogenated at 35-45 DEG C, 0.4-0.8 MPa under the action of metal catalyst. The reaction uses heavy metal catalyst, which can cause the product to exceed the standard of heavy metal, increase the difficulty of filtration, and at the same time, the required pressure in the reaction process is high, hydrogen is flammable and explosive, and the safety risk is high. Therefore, an economical and efficient preparation method of pharmaceutical pregnenolone isobutyrate is needed.

[0004] As an esterified pregnenolone derivative, pregnenolone isobutyrate is commonly esterified by acyl chloride method, acid anhydride method or using DCC / DMAP condensing agent. However, isobutyric acid is difficult to form acid anhydride due to too large steric hindrance, and is not easy to use acid anhydride method; acyl chloride method needs to use reagents such as thionyl chloride or oxalyl chloride, which has high risk in industrial production and also produces a large amount of waste gas to cause environmental pollution; the hydroxyl group of pregnenolone is at position 3, and has low activity, and a long reaction time and high temperature may be needed when using DCC / DMAP condensing agent, and the reaction condition is harsh. Therefore, in order to improve the product quality of pregnenolone isobutyrate to meet the pharmaceutical demand, it is urgent to develop an economical and efficient preparation method of pharmaceutical pregnenolone isobutyrate with low environmental pollution, high pregnenolone isobutyrate content, high yield, simple post-treatment operation and suitable for industrial production. SUMMARY

[0005] The purpose of the present application is to overcome the deficiencies of the prior art, and provide a preparation method of pharmaceutical pregnenolone isobutyrate with low production cost, small environmental pollution, high pregnenolone isobutyrate content, high yield, simple post-treatment operation and meeting the industrial production standard of pharmaceutical enterprises.

[0006] The technical scheme of the present application is outlined as follows:

[0007] The method for preparing pharmaceutical pregnenolone isobutyrate comprises the following steps:

[0008] (1) The isobutyric acid I, organic solvent A and acid-binding agent are added into a reaction container in the ratio of 1:6-8.5:0.8-1.3 by mass, and stirred uniformly under nitrogen atmosphere; the temperature is lowered to -10-0°C, and the solution of organic phosphorus condensing agent in organic solvent A is added dropwise under stirring, and reacted at -10-0°C for 3-5 hours to obtain a reaction solution containing intermediate II, wherein the molar ratio of isobutyric acid to organic phosphorus condensing agent is 1:1-1.5;

[0009] (2) The 6M solution of pregnenolone III in organic solvent A is added dropwise into the reaction solution containing intermediate II, wherein the molar ratio of pregnenolone to isobutyric acid is 0.7-1:1; the temperature is raised to 15-35°C, and reacted for 3-6 hours to obtain a reaction solution containing pregnenolone isobutyrate IV;

[0010] (3) The reaction solution obtained in step (2) is filtered, and the filtrate is concentrated under reduced pressure to remove the organic solvent A and acid-binding agent, and dissolved in the mixture of n-hexane / ethyl acetate with a volume ratio of 10 / 1, and passed through a 100-200 mesh silica gel column, and eluted with n-hexane / ethyl acetate with a volume ratio of 8 / 1 as the mobile phase, and spotted on a TLC plate, wherein the developing agent of the TLC plate is n-hexane / ethyl acetate with a volume ratio of 5 / 1; the eluent containing pregnenolone isobutyrate is collected, and concentrated under reduced pressure to completely remove n-hexane / ethyl acetate, and obtain a concentrated solution;

[0011] (4) The concentrated solution obtained in step (3) is added with organic solvent B, and the temperature is raised to 45-80°C, and stirred for 0.5-1.5 hours; the temperature is lowered to 10-35°C, and filtered to obtain a filter cake;

[0012] (5) The filter cake obtained in step (4) is washed with organic solvent B, and dried to obtain pharmaceutical pregnenolone isobutyrate IV.

[0013] Preferably, the organic solvent A is dichloromethane, acetonitrile or toluene.

[0014] Preferably, the acid-binding agent is triethylamine, pyridine or diisopropyl ethylamine.

[0015] Preferably, the molar ratio of isobutyric acid to organic phosphorus condensing agent is 1:1.1-1.35.

[0016] Preferably, the organic phosphorus condensing agent is bis(2-oxo-3-oxazolidinyl) chlorophosphite, diphenyl chlorophosphite or propyl phosphonic anhydride; the bis(2-oxo-3-oxazolidinyl) chlorophosphite is abbreviated as BOP-Cl; the diphenyl chlorophosphite is abbreviated as DPP-Cl; and the propyl phosphonic anhydride is abbreviated as T3P.

[0017] Preferably, the organic solvent B is 0.15-0.6 times the mass of the pregnenolone in step (2).

[0018] Preferably, the organic solvent B is n-hexane, petroleum ether, acetone or ethyl acetate.

[0019] Advantages of the present application:

[0020] 1. The present application uses ester condensation method to prepare pharmaceutical pregnenolone isobutyrate, compared with the traditional esterification method, the method has higher reactivity of active ester (compound II), mild reaction conditions, fast reaction rate and high yield.

[0021] 2. The organic phosphorus condensing agent used in the present application can easily extract the water-soluble by-products into water, greatly reducing the purification difficulty and simplifying the post-treatment;

[0022] 3. The present application uses column chromatography and recrystallization purification process, which has high purification efficiency and a yield of more than 84.0%;

[0023] 4. Based on the accurate control of experimental conditions and test parameters, the pregnenolone isobutyrate obtained by the present application has a content of more than 99.5%, an acid value of less than 0.1 and a moisture content of less than 0.1%, which has excellent quality and meets the pharmaceutical requirements;

[0024] 5. The production process used in the present application has controllable safety, easy-to-obtain raw materials, low production cost, environmental friendliness and small pollution, and is suitable for industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 GC spectrum of the pharmaceutical pregnenolone isobutyrate. 1 H-NMR spectrum.

[0026] Figure 2 GC spectrum of the pharmaceutical pregnenolone isobutyrate.

[0027] Figure 3 Synthesis route of the pharmaceutical pregnenolone isobutyrate. DETAILED DESCRIPTION

[0028] The organic phosphorus condensing agent used in the present application is bis(2-oxo-3-oxazolidinyl) chlorophosphine, diphenyl chlorophosphoryl or propyl phosphonic anhydride; wherein bis(2-oxo-3-oxazolidinyl) chlorophosphine is abbreviated as BOP-Cl; diphenyl chlorophosphoryl is abbreviated as DPP-Cl; and the propyl phosphonic anhydride is abbreviated as T3P.

[0029] BOP-Cl (Jiangsu Jitai Peptide Technology Co., Ltd.); DPP-Cl (Zhen De Chemical Technology (Shanghai) Co., Ltd.); T3P (Hubei Hengjingrui Chemical Co., Ltd.) are taken as examples, but the present application is not limited thereto.

[0030] The preparation method of the organic solvent A solution of the organic phosphorus condensing agent in each embodiment is as follows: 100 g of the organic phosphorus condensing agent is added into 150 g of the organic solvent A in proportion, and stirred and dissolved until clear.

[0031] The following examples further describe the present application in detail, which should not be understood as limiting the claims of the present application.

[0032] Example 1

[0033] The preparation method of the pharmaceutical pregnenolone isobutyrate includes the following steps:

[0034] (1) Isobutyric acid I 1000 g (11.35 mol), dichloromethane 8500 g (8.5 times), and triethylamine 800 g (0.8 times) are sequentially added into a reaction container, and stirred uniformly under a nitrogen atmosphere; cooled to 0°C, and BOP-Cl dichloromethane solution (the mass of the solution is 10837.89 g, and BOP-Cl is 17.03 mol, 1.5 times) is added dropwise under stirring at 0°C, and reacted for 3 hours to obtain a reaction liquid containing intermediate II-2, as shown in Figure 3 ;

[0035] (2) 6M pregnenolone III dichloromethane solution is added dropwise into the reaction liquid containing intermediate II-2, and the molar ratio of the pregnenolone to isobutyric acid is 0.7:1 (pregnenolone is 2516.0 g, 7.95 mol); warmed to 35°C, and reacted for 3 hours to obtain a reaction liquid containing pregnenolone isobutyrate IV;

[0036] (3) The reaction liquid obtained in step (2) is filtered, the filtrate is concentrated under reduced pressure to remove dichloromethane and triethylamine, dissolved in a mixture of n-hexane / ethyl acetate with a volume ratio of 10 / 1, passed through a 100-200 mesh silica gel column, eluted with n-hexane / ethyl acetate with a volume ratio of 8 / 1 as the mobile phase, spotted on a TLC plate, the developing agent of the TLC plate is n-hexane / ethyl acetate with a volume ratio of 5 / 1, the eluent containing pregnenolone isobutyrate is collected, and n-hexane / ethyl acetate is completely removed by reduced pressure concentration to obtain a concentrated liquid;

[0037] (4) Petroleum ether 1509.6 g (the mass of the petroleum ether is 0.6 times the mass of the pregnenolone in step (2)) is added into the concentrated liquid obtained in step (3), warmed to 80°C, and stirred for 0.5 hours; cooled to 35°C, and filtered to obtain a filter cake;

[0038] (5) The filter cake is washed with petroleum ether, and dried to obtain the pharmaceutical pregnenolone isobutyrate IV.

[0039] The product was sampled and tested for quality. The qualified product was then sub-packed and stored. 1 H-NMR spectrum (see Figure 1 )2608.8g, purification yield 84.89%. The GC spectrum of the pharmaceutical pregnenolone isobutyrate is shown in Figure 2 , and the quality indicators were in line with the pharmaceutical enterprise standards, as shown in Table 1.

[0040] Example 2

[0041] The method for preparing pharmaceutical pregnenolone isobutyrate includes the following steps:

[0042] (1) Isobutyric acid I 1000g (11.35mol), toluene 6000g (6 times), and diisopropyl ethylamine 1300g (1.3 times) were sequentially added to a reaction container, and stirred uniformly under a nitrogen atmosphere. The temperature was lowered to -10°C, and T3P toluene solution (9028.36g, T3P was 11.35mol) was added dropwise under stirring. The reaction was carried out at -10°C for 5 hours to obtain a reaction liquid containing intermediate II-3, as shown in Figure 3 ;

[0043] (2) 6M pregnenolone III toluene solution was added dropwise to the reaction liquid containing intermediate II-3, and the molar ratio of pregnenolone to isobutyric acid was 1:1 (pregnenolone was 3592.0g, 11.35mol). The temperature was raised to 15°C, and the reaction was carried out for 6 hours to obtain a reaction liquid containing pregnenolone isobutyrate IV;

[0044] (3) The reaction liquid obtained in step (2) was filtered, and the filtrate was concentrated under reduced pressure to remove toluene and diisopropyl ethylamine. The concentrated liquid was dissolved in a mixture of n-hexane / ethyl acetate with a volume ratio of 10 / 1, and passed through a 100-200 mesh silica gel column. N-hexane / ethyl acetate with a volume ratio of 8 / 1 was used as the mobile phase for elution. The TLC plate was spotted, and the developing agent for the TLC plate was n-hexane / ethyl acetate with a volume ratio of 5 / 1. The eluent containing pregnenolone isobutyrate was collected, and n-hexane / ethyl acetate was completely removed by reduced pressure concentration to obtain a concentrated liquid;

[0045] (4) To the concentrated liquid obtained in step (3), 538.8g of acetone was added (the mass of acetone was 0.15 times the mass of pregnenolone in step (2)), and the temperature was raised to 45°C. The mixture was stirred for 1.5 hours, and then the temperature was lowered to 10°C. The mixture was filtered to obtain a filter cake;

[0046] (5) The filter cake was washed with acetone and dried to obtain pharmaceutical pregnenolone isobutyrate IV.

[0047] The product was sampled and tested for quality. The qualified product was then sub-packed and stored.3685.9g, purification yield 84.01%. The quality indicators were in line with the pharmaceutical enterprise standards, as shown in Table 1.

[0048] Example 3

[0049] The method for preparing the pharmaceutical pregnenolone isobutyrate comprises the following steps:

[0050] (1) Isobutyric acid I 1000g (11.35mol), acetonitrile 8000g (8 times), pyridine 900g (0.9 times) are sequentially added into a reaction container, stirred uniformly under nitrogen atmosphere, reduced to -6°C, and T3P (1.35 times) acetonitrile solution (12186.29g, T3P is 15.32mol) is added dropwise under stirring at -6°C, reacted for 4 hours at -6°C to obtain a reaction solution containing intermediate II-3, see Figure 3 ;

[0051] (2) 6M pregnenolone III acetonitrile solution is added dropwise into the reaction solution containing intermediate II-3, the molar ratio of the pregnenolone to isobutyric acid is 0.8:1 (pregnenolone is 2873.6g, 9.08mol); the temperature is increased to 30°C, and reacted for 4 hours to obtain a reaction solution containing pregnenolone isobutyrate IV;

[0052] (3) The reaction solution obtained in step (2) is filtered, the filtrate is concentrated under reduced pressure to remove acetonitrile and pyridine, dissolved with a mixture of n-hexane / ethyl acetate with a volume ratio of 10 / 1, passed through a 100-200 mesh silica gel column, eluted with n-hexane / ethyl acetate with a volume ratio of 8 / 1 as the mobile phase, spotted on a TLC plate, the developing agent of the TLC plate is n-hexane / ethyl acetate with a volume ratio of 5 / 1, the eluent containing pregnenolone isobutyrate is collected, and n-hexane / ethyl acetate is completely removed under reduced pressure to obtain a concentrated solution;

[0053] (4) 1293.1g of n-hexane (the mass of n-hexane is 0.45 times the mass of pregnenolone in step (2)) is added into the concentrated solution obtained in step (3), the temperature is increased to 75°C, and stirred for 0.6 hours. The temperature is reduced to 25°C, filtered to obtain a filter cake;

[0054] (5) The filter cake is washed with n-hexane, dried to obtain the pharmaceutical pregnenolone isobutyrate IV.

[0055] After sampling and detecting the product to be qualified, it is stored after being divided into small packages. 2990.8g, the purification yield is 85.21%. After inspection, the quality indicators all meet the pharmaceutical enterprise standards, see Table 1.

[0056] Example 4

[0057] The method for preparing the pharmaceutical pregnenolone isobutyrate comprises the following steps:

[0058] (1) Put isobutyric acid I 1000g (11.35mol), toluene 6500g (6.5 times), pyridine 1000g (1.0 times) into a reaction vessel in turn, and stir them under nitrogen atmosphere. Lower the temperature to -5°C, and drop DPP-Cl (1.1 times) toluene solution (7388.77g, DPP-Cl is 12.49mol) under stirring at -5°C. React for 4 hours at -5°C to obtain a reaction solution containing intermediate II-1, see Figure 3 ;

[0059] (2) Drop 6M pregnenolone III toluene solution into the reaction solution containing intermediate II-1, and the molar ratio of pregnenolone to isobutyric acid is 0.9:1 (pregnenolone is 3234.4g, 10.22mol). Raise the temperature to 20°C, and react for 5 hours to obtain a reaction solution containing pregnenolone isobutyrate IV;

[0060] (3) Filter the reaction solution obtained in step (2), and concentrate the filtrate under reduced pressure to remove toluene and pyridine. Dissolve it in n-hexane / ethyl acetate mixture with a volume ratio of 10 / 1, and pass it through a 100-200 mesh silica gel column. Elute it with n-hexane / ethyl acetate mixture with a volume ratio of 8 / 1 as mobile phase. Spot the TLC plate, and the developing agent of the TLC plate is n-hexane / ethyl acetate mixture with a volume ratio of 5 / 1. Collect the eluent containing pregnenolone isobutyrate, and concentrate it under reduced pressure to completely remove n-hexane / ethyl acetate to obtain a concentrated solution;

[0061] (4) Add ethyl acetate 970.3g (the mass of ethyl acetate is 0.3 times the mass of pregnenolone in step (2)) to the concentrated solution obtained in step (3), and raise the temperature to 55°C. Stir for 1 hour. Lower the temperature to 30°C, and filter to obtain a filter cake;

[0062] (5) Wash the filter cake with ethyl acetate, and dry it to obtain pharmaceutical pregnenolone isobutyrate IV.

[0063] After sampling and testing the product to be qualified, store it in separate containers, 3388.8g, and the purification yield is 85.78%. After testing, the quality indicators all meet the pharmaceutical enterprise standards, see Table 1.

[0064] Example 5

[0065] The preparation method of pharmaceutical pregnenolone isobutyrate includes the following steps:

[0066] (1)Into a reaction vessel, isobutyric acid (I) 1000g (11.35mol), dichloromethane 7000g (7 times), pyridine 1100g (1.1 times) were added successively, and stirred uniformly under nitrogen atmosphere. The temperature was lowered to -3°C, and a solution of DPP-Cl (1.2 times) in dichloromethane (8057.25g, DPP-Cl is 13.62mol) was added dropwise under stirring at -3°C. The reaction was carried out for 3.5 hours at -3°C to obtain a reaction solution containing intermediate II-1, see Figure 3 ;

[0067] (2) To the reaction solution containing intermediate II-1, a 6M solution of pregnenolone III in dichloromethane was added dropwise, and the molar ratio of pregnenolone to isobutyric acid was 0.85:1 (pregnenolone is 3054.0g, 9.65mol). The temperature was raised to 25°C, and the reaction was carried out for 4.5 hours to obtain a reaction solution containing pregnenolone isobutyrate IV;

[0068] (3) The reaction solution obtained in step (2) was filtered, and the filtrate was concentrated under reduced pressure to remove dichloromethane and pyridine. The residue was dissolved in a mixture of n-hexane / ethyl acetate (10 / 1, by volume), and passed through a 100-200 mesh silica gel column. The column was eluted with a mixture of n-hexane / ethyl acetate (8 / 1, by volume) as the mobile phase. The eluate containing pregnenolone isobutyrate was collected, and n-hexane / ethyl acetate was completely removed by concentration under reduced pressure to obtain a concentrated solution;

[0069] (4) To the concentrated solution obtained in step (3), n-hexane 1068.9g (the mass of n-hexane is 0.35 times the mass of pregnenolone in step (2)) was added, and the temperature was raised to 50°C. The mixture was stirred for 1.2 hours, and then the temperature was lowered to 20°C. The mixture was filtered to obtain a filter cake;

[0070] (5) The filter cake was washed with n-hexane, and dried to obtain pharmaceutical pregnenolone isobutyrate IV.

[0071] After sampling and testing, the product was stored after being divided into portions. The yield of the purified product was 3223.3g, and the yield was 86.41%. The quality indicators met the standards of pharmaceutical enterprises, as shown in Table 1.

[0072] Table 1: Enterprise standards and test results of pharmaceutical pregnenolone isobutyrate

[0073]

Claims

1. A method for preparing medicinal pregnenolone isobutyrate, characterized in that The following steps are involved: (1) isobutyric acid (I), organic solvent A and acid binding agent are sequentially added to a reaction vessel in a mass ratio of 1:6-8.5:0.8-1.3, and stirred evenly under a nitrogen atmosphere; the temperature is reduced to -10-0°C, and a solution of an organic phosphorus condensing agent in organic solvent A is added dropwise under stirring, and the reaction is carried out at -10-0°C for 3-5 hours to obtain a reaction solution containing the intermediate (II), wherein the molar ratio of the isobutyric acid to the organic phosphorus condensing agent is 1:1-1.5; (2) adding a solution of pregnenolone (III) in an organic solvent A dropwise to the reaction solution containing the intermediate (II), wherein the molar ratio of pregnenolone to isobutyric acid is 0.7 to 1:1; heating to 15 to 35° C. and reacting for 3 to 6 hours to obtain a reaction solution containing pregnenolone isobutyrate (IV); (3) filtering the reaction solution obtained in step (2), concentrating the filtrate under reduced pressure to remove the organic solvent A and the acid-binding agent, dissolving the filtrate with a n-hexane / ethyl acetate mixture in a volume ratio of 10 / 1, passing the filtrate through a 100-200 mesh silica gel column, eluting with n-hexane / ethyl acetate in a volume ratio of 8 / 1 as the mobile phase, spotting the filtrate on a TLC plate, using n-hexane / ethyl acetate in a volume ratio of 5 / 1 as the developing solvent, collecting the eluate containing pregnenolone isobutyrate, and concentrating the filtrate under reduced pressure to completely remove the n-hexane / ethyl acetate to obtain a concentrated solution; (4) adding organic solvent B to the concentrated solution obtained in step (3), heating to 45-80° C., stirring for 0.5-1.5 hours; cooling to 10-35° C., filtering to obtain a filter cake; (5) washing the filter cake obtained in step (4) with an organic solvent B and drying it to obtain medicinal pregnenolone isobutyrate (IV).

2. The preparation method according to claim 1, wherein The organic solvent A is dichloromethane, acetonitrile or toluene.

3. The preparation method according to claim 1, wherein The acid binding agent is triethylamine, pyridine or diisopropylethylamine.

4. The preparation method according to claim 1, wherein The molar ratio of the isobutyric acid to the organophosphorus condensing agent is 1:1.1-1.

35.

5. The preparation method according to claim 1 or 4, characterized in that The organophosphorus condensing agent is bis(2-oxo-3-oxazolidinyl)phosphinoyl chloride, diphenylphosphinoyl chloride or propylphosphonic anhydride; the bis(2-oxo-3-oxazolidinyl)phosphinoyl chloride is abbreviated as BOP-Cl; the diphenylphosphinoyl chloride is abbreviated as DPP-Cl; and the propylphosphonic anhydride is abbreviated as T3P.

6. The preparation method according to claim 1, wherein The organic solvent B is 0.15 to 0.6 times the mass of the pregnenolone in step (2).

7. The preparation method according to claim 1 or 6, characterized in that The organic solvent B is n-hexane, petroleum ether, acetone or ethyl acetate.

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