Preparation process of a key intermediate of deoxycholic acid

Abstract

The present invention provides a preparation process for a key intermediate of deoxycholic acid. Compared with the prior art, the preparation process provided by the present invention has high reaction selectivity, high conversion rate, high yield, simple post-treatment operation, fewer impurities, high product purity, low industrialization cost, and has good prospects for large-scale application.

Description

Technical Field

[0001] The present invention relates to the technical field of drug synthesis, and particularly to a preparation process of a key intermediate of deoxycholic acid. Background Art

[0002] Deoxycholic acid (3α,12α-dihydroxy-5β-cholan-24-oic acid) is a free bile acid present in bile. It has strong surface activity and can disrupt and dissolve cell membranes. When deoxycholic acid is injected into subcutaneous adipose tissue, it can physically disrupt the cell membranes of cells, thereby causing fat dissolution and producing local subcutaneous adipose tissue dissolution in a small area. In the field of medical aesthetics, deoxycholic acid injection can be used to treat and improve the protrusion of moderate to severe submental fat (double chin) in adults, so it has great commercial value. In addition, deoxycholic acid can also be synthesized with amino acids and their analogs to form complexes such as taurodeoxycholic acid.

[0003] Deoxycholic acid can also be made into various deoxycholate salts and used as pharmaceutical excipients in various preparations, such as tablets, injections, etc. However, there is no pharmaceutical-grade sodium deoxycholate on the market in China, and the commercially available sodium deoxycholate is basically extracted from animals. Although it can be used to prepare bacterial culture media, protein analysis, as an ionic detergent, and replace cephalin for cholesterol flocculation test, etc., it cannot be used as a pharmaceutical excipient in drug preparations. Therefore, the application prospects of deoxycholic acid and its salts that can be used as pharmaceutical excipients are very broad and have great market value. Based on this, the preparation processes of the key intermediates of deoxycholic acid or its salts, 7-ketocholic acid (3α,12α-dihydroxy-7-keto-5β-cholan-24-oic acid) or 7-ketocholic acid ester (3α,12α-dihydroxy-7-keto-5β-cholan-24-oic acid ester), have attracted more and more attention from researchers and enterprises.

[0004] US Patent US2321598A discloses a method for directly oxidizing cholic acid with chromium trioxide to obtain 7-ketocholic acid, in which the oxidant used is chromium trioxide and the reaction solvent is glacial acetic acid (the reaction formula is shown as follows). The disadvantage of this method is that the reaction selectivity is poor, and 3-OH and 12-OH will also be partially oxidized to carbonyl groups, resulting in more impurities and low purity in the obtained product.

[0005]

[0006] Xiao-Long He et al. (A facile synthesis of ursodeoxycholic acid and obeticholic acid from cholic acid [J] Steroids. Volume 140, December 2018, Pages 173-178) disclosed a new preparation method of 7-ketocholic acid (the reaction formula is shown below). This method uses acetone / water as the reaction solvent, and cholic acid reacts with NBS to obtain 7-ketocholic acid. The defect of this method is that the reaction conversion rate is low, there is a large amount of remaining substrate, and the reaction is incomplete.

[0007]

[0008] US Patent US2321598A disclosed a method of directly oxidizing cholic acid with chromic acid to obtain 7-ketocholic acid. This method has the defects of low reaction selectivity and too strong oxidizing property of the oxidant. The low selectivity and too strong oxidizing property of the oxidant will lead to the formation of polyketocholic acid, resulting in more product impurities, low yield, low purity, and high industrialization cost. Specifically, the reaction formula of the above method is shown below:

[0009]

[0010] In summary, it is urgent to develop a new preparation process for 7-ketocholic acid or 7-ketocholic acid ester, which is a key intermediate of deoxycholic acid. Summary of the Invention

[0011] In order to solve the deficiencies of the prior art, the present invention provides a preparation process for a key intermediate of deoxycholic acid. The preparation process provided by the present invention has high reaction selectivity, high conversion rate, high yield, simple post-treatment operation, few impurities, high product purity, low industrialization cost, and has good prospects for large-scale application.

[0012] Therefore, an object of the present invention is to provide a preparation process for a key intermediate of deoxycholic acid;

[0013] Another object of the present invention is to provide a method for preparing deoxycholic acid using the above-mentioned preparation process for a key intermediate of deoxycholic acid.

[0014] The technical solutions to achieve the above objects of the present invention are as follows.

[0015] On the one hand, the present invention provides a preparation process for a key intermediate of deoxycholic acid, and the reaction route of the preparation process is as follows:

[0016]

[0017] Among them, in the said preparation process, using compound I as the raw material, in an organic solvent, with o-iodoxybenzoic acid (INX) as the oxidant, an oxidation reaction is carried out to obtain compound II;

[0018] Among them, in compound I and compound II, the R group is any one selected from hydrogen, methyl, ethyl, isopropyl, propyl and butyl, preferably methyl.

[0019] In a specific embodiment of the present invention, the structure of the o-iodoxybenzoic acid (INX) is as follows:

[0020]

[0021] Furthermore, the molar ratio of compound I to o-iodoxybenzoic acid (INX) is 1:1.0 to 1:5.0, preferably 1:1.0 to 1:1.5, more preferably 1:1.5;

[0022] Furthermore, the organic solvent is one or more selected from DMF, DMSO, THF and ethylene glycol. Preferably, the organic solvent is a mixed solvent of DMSO and THF. More preferably, in the mixed solvent of DMSO and THF, the volume ratio of DMSO to THF is 4:1 to 8:1, and further preferably 6:1;

[0023] Furthermore, the reaction concentration of compound I is 20 mg / ml - 40 mg / ml, preferably 28 mg / ml - 34 mg / ml; more preferably 33.3 mg / ml;

[0024] Furthermore, the oxidation reaction is carried out at 20 - 100 °C, preferably at 40 - 60 °C, more preferably at 50 °C; furthermore, the time of the oxidation reaction is 8 - 36 h, preferably 8 - 12 h, more preferably 12 h.

[0025] Furthermore, after the oxidation reaction is completed, the preparation process further includes a post-treatment process for compound II, and the post-treatment process includes the following steps:

[0026] i) Add purified water to the reaction solution after the oxidation reaction is completed, crystallize, and filter;

[0027] ii) Wash the solid obtained in step i) with ethyl acetate, extract and separate with saturated NaHCO3 to obtain an organic phase, crystallize, filter by suction, and dry to obtain the product.

[0028] Furthermore, in step ii) of the above post-treatment process, the organic solvent used for crystallization is selected from n-hexane, cyclohexane and n-heptane, preferably n-hexane.

[0029] In a specific embodiment, the preparation process of the key intermediate of deoxycholic acid provided by the present invention is carried out as follows:

[0030] Compound I and iodylnaphthoic acid (INX) with a molar ratio of 1:1.5 are dissolved in a mixed solvent of DMSO and THF with a volume ratio of 6:1, reacted at 50 °C for 12 h, purified water is added, crystallization occurs, filtration is carried out, the solid is washed with ethyl acetate, extracted and separated with saturated NaHCO3, the organic phase is retained, dried over anhydrous Na2SO4, and then n-hexane is added dropwise for crystallization, suction filtration and drying to obtain the product.

[0031] On the other hand, the present invention provides a method for preparing deoxycholic acid using the above preparation process, and the reaction route of the method is as follows:

[0032]

[0033] Wherein, the R group is any one selected from hydrogen, methyl, ethyl, isopropyl, propyl and butyl, preferably methyl;

[0034] Wherein, the method comprises the following steps:

[0035] (1) Oxidation reaction: Compound I is subjected to an oxidation reaction to obtain Compound II, and the oxidant used for the oxidation reaction is iodylnaphthoic acid (INX);

[0036] (2) Reduction reaction: Compound II obtained in step (1) is subjected to a reduction reaction under the conditions of hydrazine hydrate and a base to obtain deoxycholic acid (Compound III).

[0037] Preferably, in step (1), the oxidation reaction is carried out in one or more solvents selected from DMF, DMSO, THF and ethylene glycol, preferably in a mixed solvent containing DMSO and THF; further preferably, in the mixed solvent containing DMSO and THF, the volume ratio of DMSO to THF is 4:1 to 8:1, and more preferably 6:1;

[0038] Preferably, the reaction concentration of Compound I is 20 mg / ml - 40 mg / ml, preferably 28 mg / ml - 34 mg / ml; more preferably 33.3 mg / ml;

[0039] Preferably, the oxidation reaction is carried out at 20 - 100 °C, more preferably at 40 - 60 °C; still more preferably at 50 °C; further preferably, the reaction time of the oxidation reaction is 8 - 36 h, preferably 8 - 12 h, more preferably 12 h;

[0040] Preferably, the molar ratio of Compound I to iodosobenzoic acid (INX) is from 1:1.0 to 1:5.0, preferably from 1:1.0 to 1:1.5, and more preferably 1:1.5;

[0041] Preferably, after step (1) and before step (2), the method further comprises a post-treatment process for Compound II, wherein the post-treatment process comprises the following steps:

[0042] i) Add purified water to the reaction solution after the oxidation reaction is completed, crystallize, and filter;

[0043] ii) Wash the solid obtained in step i) with ethyl acetate, extract and separate with saturated NaHCO3 to obtain an organic phase, crystallize, filter by suction, and dry to obtain the product.

[0044] Further, in step ii) of the above post-treatment process, the organic solvent used for crystallization is selected from n-hexane, cyclohexane, and n-heptane, and preferably n-hexane.

[0045] Further, in step (2), the base is an inorganic base. More preferably, the base is selected from one or more of KOH, NaOH, and LiOH, and further preferably KOH;

[0046] Preferably, the hydrazine hydrate is 50% (w / w) hydrazine hydrate;

[0047] Preferably, the molar ratio of Compound II to hydrazine hydrate is from 1:10 to 1:70, more preferably from 1:20 to 1:30, and further preferably 1:25;

[0048] Preferably, the molar ratio of Compound II to the base is from 1:10 to 1:40, more preferably 1:20 to 1:40, and further preferably 1:30;

[0049] Preferably, in step (2), the reduction reaction comprises steps of forming hydrazone and decomposing hydrazone. Further preferably, the reaction of forming hydrazone is carried out at 100 - 120 °C, preferably 105 - 115 °C for 2 - 6 h, preferably 3 h; More preferably, the reaction of decomposing hydrazone is carried out at 140 - 220 °C, preferably 175 - 195 °C for 2 - 6 h, preferably 3 h. In some specific embodiments, the reaction of forming hydrazone is carried out at 110 °C for 3 h, and the reaction of decomposing hydrazone is carried out at 180 °C for 3 h.

[0050] Preferably, in step (2), the reduction reaction is carried out in diethylene glycol.

[0051] Further, the method for preparing deoxycholic acid provided by the present invention further includes the step of (3) refining deoxycholic acid; preferably, the refining of deoxycholic acid is carried out as follows: Compound III is dissolved in tetrahydrofuran at 55°C, and a mixed solvent of acetonitrile and dichloromethane is added dropwise to precipitate a white solid. After cooling to room temperature, filtration is carried out to obtain deoxycholic acid. In some specific embodiments, the refining of deoxycholic acid is carried out as follows: Compound III is dissolved in tetrahydrofuran at 55°C, and a mixed solvent of acetonitrile and dichloromethane with a volume ratio of 1.5:1 is added dropwise to precipitate a white solid. After cooling to 25°C, filtration is carried out to obtain deoxycholic acid.

[0052] Compared with the prior art, the advantages of the present invention at least include the following aspects:

[0053] The present invention provides a preparation process for a key intermediate of deoxycholic acid. This process uses cholic acid or cholate as a substrate and a novel oxidant, iodosonaphthoic acid (INX). By controlling specific reaction conditions, the 7-OH in cholic acid or cholate can be highly selectively oxidized, while the 3-OH and 12-OH are hardly oxidized. Therefore, the preparation process provided by the present invention has high reaction selectivity, high conversion rate, simple post-treatment operation, fewer impurities, high yield, high purity, low industrialization cost, and has a good prospect for large-scale application.

[0054] Regarding the novel oxidant iodosonaphthoic acid (INX) used in the present invention, the inventors have found through research that due to the large spatial volume of the naphthalene ring in iodosonaphthoic acid, the skeletal structure of the aromatic ring is changed. While retaining the oxidation activity of the traditional catalyst iodosobenzoic acid (IBX), the selectivity of this oxidant for the oxidation of hydroxyl groups at different positions of rigid structure substrates such as steroids can be improved. Therefore, INX has high oxidation reaction selectivity.

[0055] For different reaction substrates, the control of reaction conditions is particularly important. When oxidizing methyl cholate, the molar ratio of methyl cholate to iodosonaphthoic acid, the temperature and time of the oxidation reaction, and the selection of organic solvents in the reaction system jointly affect the reaction yield and product purity of the oxidation of the 7-position hydroxyl group. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings, where:

[0057] Figure 1 Shows the reaction route of the method for preparing deoxycholic acid provided by the present invention.

[0058] Figure 2 Shows the mass spectrum of Compound II (R is -CH3).

[0059] Figure 3The 1H NMR spectrum of Compound II (R is -CH3) is shown.

[0060] Figure 4 The 13C NMR spectrum of Compound II (R is -CH3) is shown.

[0061] Figure 5 The mass spectrum of Compound III is shown.

[0062] Figure 6 The 1H NMR spectrum of Compound III is shown.

[0063] Figure 7 The 13C NMR spectrum of Compound III is shown. Detailed implementation manners

[0064] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content disclosed in the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0065] In the embodiments of the present invention, unless otherwise specified, the reaction route adopted is as follows:

[0066]

[0067] Examples 1 - 6:

[0068] (1) Synthesis of Compound II (R is -CH3):

[0069] Dissolve o-iodoxybenzoic acid INX (specific dosage is shown in Table 1) in a mixed solvent of 600 ml of DMSO and THF (volume ratio 6:1), then add Compound I (R is -CH3) (20 g, 47.33 mmol), heat up to 50 °C, stir and react for 12 h. After HPLC detection shows the reaction is completed, add 600 ml of purified water, a large amount of white solid precipitates. Filter by suction, wash the solid 3 times with 200 ml of ethyl acetate in portions, combine the liquid phases, add 100 ml of saturated NaHCO3, stir and then let it stand for liquid separation. Retain the organic phase, dry it over anhydrous Na2SO4, then add 500 ml of n-hexane to crystallize, filter by suction and dry to obtain Compound II (R is -CH3). Characterize the Compound II obtained in Example 3, and the results are as Figures 2 - 4 shown, and the characterization data are as follows: ESI-MS m / z = 465.9 [M+HCOO] - , 11H NMR (400 MHz, DMSO-d6) δ 4.49 (d, J = 4.6 Hz, 1H), 4.30 (d, J = 4.0 Hz, 1H), 3.80 (d, J = 3.5 Hz, 1H), 3.57 (s, 3H), 3.36 (ddd, J = 15.1, 7.5, 3.7 Hz, 1H), 2.87 (dd, J = 12.4, 5.9 Hz, 1H), 2.41 (t, J = 11.6 Hz, 1H), 2.32 (ddd, J = 14.6, 9.4, 4.8 Hz, 1H), 2.17 (dtd, J = 24.9, 12.3, 10.6, 5.5 Hz, 2H), 2.07 - 1.95 (m, 1H), 1.93 - 1.82 (m, 1H), 1.81 - 1.53 (m, 7H), 1.52 - 1.36 (m, 3H), 1.34 - 1.14 (m, 4H), 1.11 (s, 3H), 1.09 - 0.80 (m, 6H), 0.59 (s, 3H) ppm; 13 13C NMR (100 MHz, DMSO-d6) δ 211.31, 173.70, 70.04, 69.13, 51.12, 48.77, 45.91, 45.39, 45.26, 45.05, 40.20, 37.42, 35.30, 34.77, 34.30, 33.83, 30.68, 30.44, 29.66, 29.21, 27.26, 23.99, 22.59, 16.95, 12.45 ppm.

[0070] Table 1

[0071]

[0072] Table 1 shows that when the molar ratio of Compound I to INX is 1:0.5, there is a large amount of raw materials remaining and the reaction is incomplete; when the molar ratio of Compound I to INX is in the range of 1:1.0 - 1:5.0, the mass yield of Compound II is about 90%; when the molar ratio is greater than or equal to 1:1.5, the mass yield of Compound II no longer increases, but the purity decreases; therefore, the molar ratio of Compound I to INX is preferably 1:1.0 - 1:1.5.

[0073] (2) Synthesis of Compound III:

[0074] Dissolve compound II (R is -CH3) (18.4 g, 43.75 mmol) in 184 ml of diethylene glycol, add KOH (73.6 g, 1.31 mol) and 50% hydrazine hydrate (109.48 g, 1.09 mol), react at 110 °C for 3 h, distill off 50% hydrazine hydrate under atmospheric pressure, raise the temperature to 180 °C and react for 3 h, stop the reaction, add 552 ml of purified water, slowly add concentrated hydrochloric acid dropwise until acidic, precipitate a white solid, filter by suction and dry to obtain compound III (15.4 g of white solid, mass yield 84%).

[0075] (3) Refinement of deoxycholic acid:

[0076] Dissolve compound III (15.4 g, 39.23 mmol) in 77 ml of tetrahydrofuran at 55 °C, add dropwise a mixed solvent of 231 ml of acetonitrile and 154 ml of dichloromethane, precipitate a white solid, cool to room temperature (25 °C) and filter by suction to obtain deoxycholic acid (14.1 g, mass yield 92%). Characterize compound III obtained in Example 3, and the results are as Figures 5 - 7 shown. The characterization data are as follows: ESI-MS m / z = 391.5 [M-H] - , 1 H NMR (400 MHz, DMSO-d6) δ 11.91 (s, 1H), 4.45 (d, J = 4.3 Hz, 1H), 4.19 (d, J = 4.1 Hz, 1H), 3.78 (q, J = 3.1 Hz, 1H), 3.36 (s, 1H), 2.22 (ddd, J = 15.1, 9.6, 5.2 Hz, 1H), 2.09 (ddd, J = 15.7, 9.2, 6.8 Hz, 1H), 1.77 (qt, J = 9.0, 4.3 Hz, 4H), 1.69 - 1.42 (m, 6H), 1.41 - 1.24 (m, 8H), 1.18 (td, J = 11.3, 9.4, 6.3 Hz, 3H), 1.02 (ddd, J = 25.7, 13.0, 4.5 Hz, 2H), 0.91 (d, J = 6.4 Hz, 3H), 0.87 (d, J = 3.3 Hz, 1H), 0.84 (s, 3H), 0.59 (s, 3H) ppm; 13 C NMR (100 MHz, DMSO-d6) δ 174.91, 70.99, 69.94, 47.45, 46.16, 45.99, 41.60, 36.29, 35.64, 35.14, 34.96, 33.81, 32.91, 30.83, 30.74, 30.23, 28.59, 27.17, 26.98, 26.09, 23.50, 23.08, 16.91, 12.43 ppm.

[0077] Examples 7 - 13

[0078] (1) Synthesis of Compound II (R is -CH3):

[0079] Dissolve o-iodoxybenzoic acid INX (23.43 g, 80.00 mmol) in 600 ml of reaction solvent (specific solvent types are shown in Table 2), then add Compound I (R is -CH3) (20.0 g, 47.33 mmol), heat up to 50 °C, stir and react for 12 h. After the reaction is completed as detected by HPLC, add 600 ml of purified water, a large amount of white solid will precipitate. Filter by suction, wash the solid 3 times with 200 ml of ethyl acetate in portions, combine the liquid phases, add 100 ml of saturated NaHCO3 for extraction and separation, retain the organic phase, dry it over anhydrous Na2SO4, then add 500 ml of n-hexane to crystallize, filter by suction and dry to obtain Compound II (R is -CH3).

[0080] Table 2

[0081]

[0082]

[0083] Table 2 shows that when the reaction solvent is a single DMF, DMSO or THF, the yield is relatively low; when the reaction solvent is ethylene glycol, although the mass yield of Compound II is high, the product purity is relatively low; when the reaction solvent is a mixed solvent of DMSO and THF with a volume ratio of 4:1 to 8:1, the mass yield of Compound II is about 92% - 94%, and the purity is relatively high. Therefore, the reaction solvent is preferably a mixed solvent of DMSO and THF, and more preferably a mixed solvent of DMSO and THF with a volume ratio of 4:1 to 8:1.

[0084] The experimental operations of steps (2) and (3) are consistent with the corresponding steps of Examples 1 - 6.

[0085] Examples 14 - 19

[0086] (1) Synthesis of Compound II (R is -CH3):

[0087] Dissolve o-iodosobenzoic acid INX (23.43 g, 80.00 mmol) in 600 ml of reaction solvent (DMSO:THF = 6:1), then add Compound I (R is -CH3) (20.0 g, 47.33 mmol), raise the temperature to 50 °C, and stir the reaction (the reaction time is shown in Table 3). After the reaction is completed as detected by HPLC, add 600 ml of purified water, and a large amount of white solid will precipitate. Filter by suction, wash the solid 3 times with 200 ml of ethyl acetate in portions, combine the liquid phases, add 100 ml of saturated NaHCO3 for extraction and separation, retain the organic phase, dry it over anhydrous Na2SO4, then add 500 ml of n-hexane dropwise for crystallization, and filter by suction and dry to obtain Compound II (R is -CH3).

[0088] Table 3

[0089]

[0090]

[0091] Table 3 shows that when the reaction time is 5 h, there are still raw materials remaining as detected by HPLC, and the reaction does not proceed further; when the reaction time is greater than or equal to 8 h, the reaction is completed as detected by HPLC. Therefore, the reaction time is preferably 8 - 12 h.

[0092] The experimental operations of steps (2) and (3) are consistent with the corresponding steps in Examples 1 - 6.

[0093] Examples 20 - 24

[0094] (1) Synthesis of Compound II (R is -CH3):

[0095] Dissolve o-iodosobenzoic acid INX (23.43 g, 80.00 mmol) in 600 ml of reaction solvent (DMSO:THF = 6:1), then add Compound I (R is -CH3) (20.0 g, 47.33 mmol), stir the reaction for 12 h (the reaction temperature is shown in Table 4). After the reaction is completed as detected by HPLC, add 600 ml of purified water, and a large amount of white solid will precipitate. Filter by suction, wash the solid 3 times with 200 ml of ethyl acetate in portions, combine the organic phases, add 100 ml of saturated NaHCO3 for extraction and separation, retain the organic phase, dry it over anhydrous Na2SO4, then add 500 ml of n-hexane dropwise for crystallization, and filter by suction and dry to obtain Compound II (R is -CH3).

[0096] Table 4

[0097]

[0098] Table 4 shows that when the reaction temperature is 20 °C, there is still raw material remaining after 12 h of reaction, and the reaction time needs to be extended to complete the reaction; when the reaction temperature is between 40 °C and 60 °C, the reaction proceeds normally; when the reaction temperature is between 80 °C and 100 °C, the reaction is intense, boiling, and there is a reflux phenomenon; therefore, the reaction temperature is preferably 40 °C to 60 °C.

[0099] The experimental operations of steps (2) and (3) are consistent with the corresponding steps in Examples 1 to 6.

[0100] Examples 25 - 29

[0101] (1) Synthesis of Compound II (R is -CH3):

[0102] Dissolve o-iodoxybenzoic acid INX (23.43 g, 80.00 mmol) in a mixed solvent of DMSO:THF = 6:1 (volume ratio), then add Compound I (R is -CH3) (20.0 g, 47.33 mmol), heat up to 50 °C, stir and react for 12 h. After HPLC detection shows the reaction is complete, add purified water with the same volume as the reaction solvent, a large amount of white solid precipitates, filter by suction, wash the solid 3 times with 200 ml of ethyl acetate, combine the organic phases, add 100 ml of saturated NaHCO3 for extraction and separation, retain the organic phase, dry over anhydrous Na2SO4, then add 500 ml of n-hexane to crystallize, filter by suction and dry to obtain Compound II (R is -CH3).

[0103] The usage amount of the mixed solvent of DMSO and THF and the reaction results are shown in Table 5 below.

[0104] Table 5

[0105]

[0106] Table 5 shows that when the reaction concentration of Compound I is 50 mg / ml, the reaction materials are not completely dissolved and the reaction does not proceed further; when the reaction concentration of Compound I is 40 - 20 mg / ml, the reaction proceeds normally; to avoid excessive solvent volume and obtain a higher purity of Compound II, the reaction concentration of Compound I is preferably 28 - 34 mg / ml.

[0107] The experimental operations of steps (2) and (3) are consistent with the corresponding steps in Examples 1 to 6.

[0108] Examples 30 - 33

[0109] (1) Synthesis of Compound II (R is -CH3):

[0110] Dissolve o-iodosobenzoic acid INX (23.43 g, 80.00 mmol) in 600 ml of reaction solvent (DMSO:THF = 6:1), then add compound I (R is -CH3) (20.0 g, 47.33 mmol), heat up to 50 °C, stir and react for 12 h. After the reaction is completed as detected by HPLC, add 600 ml of purified water, a large amount of white solid precipitates. Filter by suction, wash the solid 3 times with 200 ml of ethyl acetate in portions, combine the organic phases, add 100 ml of saturated NaHCO3 for extraction and separation of liquid layers, retain the organic phase, dry over anhydrous Na2SO4, then add 500 ml of solvent for crystallization (the types of solvents added are shown in Table 6), filter by suction and dry to obtain compound II (R is -CH3).

[0111] Table 6

[0112] Example number Solvent type Mass yield of Compound II Purity of Compound II 30 n - Hexane 93.8％(18.76g) 99.4％ 31 Cyclohexane 92.3％(18.46g) 96.7％ 32 Isopropyl ether Not precipitated -- 33 n - Heptane 91.2％(18.24g) 99.3％

[0113] Table 6 shows that when the solvent is isopropyl ether, no solid can be precipitated; when the solvent is n-hexane, cyclohexane or n-heptane, the crystallization is normal.

[0114] The experimental operations of steps (2) and (3) are consistent with the corresponding steps of Examples 1 to 6.

Claims

1. A preparation process of a key intermediate of deoxycholic acid, and the reaction route of the preparation process is as follows: Among them, In the preparation process, using compound I as a raw material, an oxidation reaction is carried out with iodosobenzoic acid (INX) as an oxidant in an organic solvent to obtain compound II; Wherein, in compound I and compound II, the R group is any one selected from hydrogen, methyl, ethyl, isopropyl, propyl and butyl; Wherein, the molar ratio of compound I to iodosobenzoic acid (INX) is 1:1.0 - 1:1.5; The organic solvent is a mixed solvent of DMSO and THF, wherein the volume ratio of DMSO to THF is 4:1 - 8:1; The reaction concentration of compound I is 28mg / ml - 34mg / ml; The oxidation reaction is carried out at 40 - 60 °C; The time of the oxidation reaction is 8 - 12h; Wherein, after the oxidation reaction ends, the preparation process further includes a post-treatment process of compound II, and the post-treatment process includes the following steps: i) Add purified water to the reaction solution after the oxidation reaction ends, crystallize, and filter; ii) Wash the solid obtained in step i) with ethyl acetate, extract and separate with saturated NaHCO3 to obtain an organic phase, crystallize, filter by suction, and dry to obtain; Wherein, in step ii) of the above post-treatment process, the organic solvent used for crystallization is selected from n-hexane and n-heptane.

2. The preparation process according to claim 1, wherein, In compound I and compound II, the R group is methyl.

3. The preparation process according to claim 1, wherein, The molar ratio of compound I to iodosobenzoic acid (INX) is 1:1.

5.

4. The preparation process according to claim 1, wherein, In the mixed solvent of DMSO and THF, the volume ratio of DMSO to THF is 6:

1.

5. The preparation process according to claim 1, wherein, The reaction concentration of compound I is 33.3mg / ml.

6. According to the preparation process described in claim 1, wherein, The oxidation reaction is carried out at 50 °C.

7. The preparation process according to claim 1, wherein, The time of the oxidation reaction is 12h.

8. The preparation process according to claim 1, wherein, In step ii) of the above post-treatment process, the organic solvent used for crystallization is n-hexane.

9. A method for preparing deoxycholic acid using the preparation process according to any one of claims 1 - 8, and the reaction route of the method is as follows: Among them, The R group is any one selected from hydrogen, methyl, ethyl, isopropyl, propyl and butyl; Wherein, the method includes the following steps: (1) Oxidation reaction: Carry out an oxidation reaction on compound I to obtain compound II, wherein the oxidant used for the oxidation reaction is iodosobenzoic acid (INX); (2) Reduction reaction: Carry out a reduction reaction on compound II obtained in step (1) under the conditions of hydrazine hydrate and a base to obtain deoxycholic acid (compound III); Wherein, in step (1), the oxidation reaction is carried out in a mixed solvent containing DMSO and THF, wherein the volume ratio of DMSO to THF is 4:1 - 8:1; The reaction concentration of compound I is 28mg / ml - 34mg / ml; The oxidation reaction is carried out at 40 - 60 °C; the time of the oxidation reaction is 8 - 12h; The molar ratio value of compound I to iodosobenzoic acid (INX) is 1:1.0 - 1:1.5; Wherein, after step (1) and before step (2), the method further includes a post-treatment process for Compound II, and the post-treatment process includes the following steps: i) Add purified water to the reaction solution after the oxidation reaction is completed, crystallize, and filter; ii) Wash the solid obtained in step i) with ethyl acetate, extract and separate with saturated NaHCO3 to obtain an organic phase, crystallize, filter by suction, and dry to obtain the product; Wherein, in step ii) of the above post-treatment process, the organic solvent used for crystallization is selected from n-hexane and n-heptane.

10. The method according to claim 9, wherein In Compound I and Compound II, the R group is a methyl group.

11. The method according to claim 9, wherein, In the mixed solvent containing DMSO and THF, the volume ratio of DMSO to THF is 6:

1.

12. The method according to claim 9, wherein, The reaction concentration of Compound I is 33.3 mg / ml.

13. The method according to claim 9, wherein The oxidation reaction is carried out at 50 °C.

14. The method according to claim 9, wherein, The time of the oxidation reaction is 12 h.

15. The method according to claim 9, wherein, In step ii) of the above post-treatment process, the organic solvent used for crystallization is n-hexane.

16. The method according to claim 9, wherein, In step (2), the base is an inorganic base.

17. The method according to claim 16, wherein The base is one or more selected from KOH, NaOH, and LiOH.

18. According to the method of claim 17, wherein the base is KOH.

19. The method according to claim 9, wherein, The hydrazine hydrate is 50% (w / w) hydrazine hydrate.

20. The method according to claim 9, wherein, The molar ratio of Compound II to hydrazine hydrate is 1:10 to 1:

70.

21. The method according to claim 20, wherein, The molar ratio of Compound II to hydrazine hydrate is 1:20 to 1:

30.

22. The method according to claim 21, wherein, The molar ratio of Compound II to hydrazine hydrate is 1:

25.

23. The method according to claim 9, wherein, The molar ratio of Compound II to the base is 1:10 to 1:

40.

24. The method according to claim 23, wherein, The molar ratio of Compound II to the base is 1:20 to 1:

40.

25. The method according to claim 24, wherein, The molar ratio of Compound II to the base is 1:

30.

26. The method according to claim 9, wherein In step (2), the reduction reaction includes the steps of forming a hydrazone and decomposing the hydrazone.

27. The method according to claim 26, wherein The reaction for forming a hydrazone is carried out at 100-120 °C for 2-6 h.

28. The method according to claim 27, wherein, The reaction for forming a hydrazone is carried out at 100-120 °C for 3 h.

29. The method according to claim 26, wherein, The reaction for forming a hydrazone is carried out at 105-115 °C for 2-6 h.

30. The method according to claim 29, wherein, The reaction for forming a hydrazone is carried out at 105-115 °C for 3 h.

31. The method according to claim 26, wherein The reaction for decomposing the hydrazone is carried out at 140-220 °C for 2-6 h.

32. The method according to claim 31, wherein, The reaction for decomposing the hydrazone is carried out at 140-220 °C for 3 h.

33. The method according to claim 26, wherein, The reaction for decomposing the hydrazone is carried out at 175-195 °C for 2-6 h.

34. The method according to claim 33, wherein, The reaction for decomposing the hydrazone is carried out at 175-195 °C for 3 h.

35. The method according to claim 26, wherein, In step (2), the reduction reaction is carried out in a diethylene glycol solvent.

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