Method for preparing dehydroepiandrosterone by aqueous phase enzyme catalysis

Abstract

The present invention discloses a method for preparing dehydroepiandrosterone by aqueous phase enzyme catalysis. The preparation method of the compound shown in Formula 3 provided by the present invention comprises the following steps: in an aqueous phase buffer system, in the presence of a nonionic auxiliary agent, glucose, 3-keto reductase, glucose dehydrogenase and NAD, the compound shown in Formula 2 is subjected to a reduction reaction as shown below to obtain a compound shown in Formula 3; the nonionic auxiliary agent is a polyoxyethylene ether auxiliary agent and / or a polysorbate auxiliary agent. The preparation method of the present invention performs an enzyme catalytic reaction in the aqueous phase, the enzyme is not easily inactivated, can be used repeatedly, reduces production costs, and less impurities are generated in the aqueous phase.

Description

Technical Field

[0001] The invention relates to a method for preparing dehydroepiandrosterone by aqueous phase enzyme catalysis. Background Art

[0002] Dehydroepiandrosterone, also known as dehydroepiandrosterone, is called dehydroepiandrosterone in English, or DHEA for short. Its chemical name is 3β-hydroxyandrost-5-ene-17-one, with a molecular formula of C19H28O2, a molecular weight of 288.43, and a CAS number of 53-43-0. Its structural formula is as follows:

[0003]

[0004] Dehydroepiandrosterone is an adrenal hormone precursor secreted by the reticular layer of the human adrenal cortex. It has physiological activities such as regulating obesity, preventing diabetes, resisting carcinogenesis and viral infection, improving memory, immune response and stress response, and reducing tension. It can participate in the synthesis of various hormones secreted by the adrenal glands and is an intermediate in the manufacture of steroid hormones.

[0005] According to literature and patent reports, the current routes for synthesizing dehydroepiandrosterone are mainly the following:

[0006] 1) Chemical method

[0007] Using 4-androstenedione (4-AD) as the raw material, the three keto groups are first esterified, then the keto group at position 17 is protected, and then reduced to obtain three hydroxyl groups, and finally the 17th position is deprotected to finally obtain dehydroepiandrosterone. The reaction formula is as follows:

[0008]

[0009] This method is a purely chemical synthesis method, which involves many steps, requires metal catalysts, generates a large amount of wastewater, and has a relatively high production cost.

[0010] 2) Biological fermentation method

[0011] Using sterol as the starting material, first protect the hydroxyl group at position 3, then remove the side chain at position 17 through fermentation to obtain the keto group at position 17, and finally hydrolyze to obtain dehydroepiandrosterone. The reaction formula is as follows:

[0012]

[0013] This method requires a fermentation method, and the stability and post-processing of the fermentation have always been key factors restricting industrialization.

[0014] 3) Bio-enzyme catalysis method

[0015] Using 4-androstenedione as the starting material, after double bond transposition, dehydroepiandrosterone is obtained by 3-keto reductase. As reported in patents CN 106086148 A, CN 109312382 A, and CN 105695551 A, after 5-androstenedione (5-AD) is synthesized, an organic phase system is used for enzyme catalysis conversion, which will increase the impurities of the product, and the organic solvent will inactivate the enzyme, increasing the production cost. The reaction formula is as follows:

[0016] Summary of the invention

[0017] The technical problem to be solved by the present invention is that the existing enzyme catalytic reaction is carried out in an organic phase, which will inactivate the enzyme and increase the impurities of the product. Therefore, the present invention provides a method for preparing dehydroepiandrosterone by enzyme catalysis in an aqueous phase. The present invention carries out the enzyme catalytic reaction in an aqueous phase, the enzyme is not easily inactivated, can be used multiple times, reduces the production cost, and at the same time, less impurities are generated in the aqueous phase.

[0018] The present invention solves the above technical problems through the following technical solutions.

[0019] The present invention provides a method for preparing a compound as shown in Formula 3, comprising the following steps: in an aqueous buffer system, in the presence of a nonionic auxiliary agent, glucose, 3-ketoreductase, glucose dehydrogenase and NAD, subjecting the compound as shown in Formula 2 to a reduction reaction as shown below, to obtain a compound as shown in Formula 3; the nonionic auxiliary agent is a polyoxyethylene ether auxiliary agent and / or a polysorbate auxiliary agent;

[0020]

[0021] In the reduction reaction, the buffer system may be a phosphate buffer solution, and the phosphate may be one or more of sodium dihydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, and dipotassium hydrogen phosphate.

[0022] In the reduction reaction, the pH of the buffer system may be 6.0 to 7.0, preferably 6.5 to 7.0, such as 7.0.

[0023] In the reduction reaction, the mass volume ratio of the compound represented by Formula 2 to the buffer system is a conventional mass volume ratio in the art, preferably 100 mg / mL to 200 mg / mL, more preferably 140 mg / mL to 160 mg / mL.

[0024] In the reduction reaction, the polyoxyethylene ether auxiliary agent is preferably Triton X-100.

[0025] In the reduction reaction, the polysorbate adjuvant is preferably Tween 60 or Tween 80, such as Tween 80.

[0026] In the reduction reaction, the mass ratio of the compound represented by formula 2 to the nonionic auxiliary agent can be (2-3):1, preferably (2.2-2.5):1.

[0027] In the reduction reaction, the reaction is carried out in the presence of a defoaming agent, and the defoaming agent can be one or more of a polysiloxane defoaming agent, a polyoxypropylene glycerol ether defoaming agent, and a silicone ether defoaming agent, preferably a silicone ether defoaming agent, such as the one produced by Yantai Hengxin Chemical Technology Co., Ltd. X-298 composite high-efficiency defoaming agent.

[0028] In the reduction reaction, the mass ratio of the compound represented by Formula 2 to the defoaming agent is a conventional mass ratio in the art, preferably (30-60):1, more preferably (45-50):1.

[0029] In the reduction reaction, the mass ratio of the compound represented by formula 2 to the glucose can be 1:(2-3), preferably 1:(2.2-2.5).

[0030] In the reduction reaction, the mass ratio of the compound represented by formula 2 to the 3-ketoreductase can be (15-22):1, preferably (18-20):1.

[0031] In the reduction reaction, the mass ratio of the 3-ketoreductase to the glucose dehydrogenase may be (3-7):1, for example, 5:1.

[0032] In the reduction reaction, the mass ratio of the 3-ketoreductase to the NAD may be (20-30):1, for example 25:1.

[0033] In the reduction reaction, the reaction temperature is a conventional temperature for this reaction in the art, preferably 20 to 40°C, such as 30°C.

[0034] The reduction reaction may further include the following steps: after the reduction reaction is completed, the reaction system is filtered, and in the filtrate, in the presence of glucose, when the pH value is 7.0, the compound represented by Formula 2 is subjected to the reduction reaction shown below to obtain a compound represented by Formula 3;

[0035]

[0036] The method for preparing the compound of formula 3 may further include the following steps: in a protective atmosphere, in a solvent, in the presence of a base, subjecting the compound of formula 1 to a double bond transposition reaction as shown below to obtain a compound of formula 2;

[0037]

[0038] In the double bond transposition reaction, the protective atmosphere may be nitrogen or an inert gas, preferably nitrogen.

[0039] In the double bond transposition reaction, the solvent is preferably an alcohol solvent, such as tert-butanol.

[0040] In the double bond transposition reaction, the mass ratio of the compound represented by Formula 1 to the solvent is a conventional mass ratio in the art, preferably 1:(3-4), for example 1:3.9.

[0041] In the double bond transposition reaction, the base is preferably an organic base, such as potassium tert-butoxide.

[0042] In the double bond transposition reaction, the mass ratio of the compound represented by Formula 1 to the base is preferably (1-1.5):1, for example 1.2:1.

[0043] In the double bond transposition reaction, the reaction temperature is a conventional temperature for this reaction in the art, preferably 20 to 40°C, such as 30°C.

[0044] The double bond transposition reaction may further include post-treatment, and the post-treatment includes the following steps: after the double bond transposition reaction is completed, the reaction system is quenched and filtered to obtain the compound shown in Formula 2.

[0045] In the double bond transposition reaction, the quenching may be performed by adding the reaction system into a quenching system.

[0046] In the double bond transposition reaction, the quenching system can be a mixed solution of acid and water.

[0047] In the double bond transposition reaction, the acid is preferably an organic acid, such as glacial acetic acid.

[0048] In the double bond transposition reaction, the mass ratio of the acid to the water may be (15-20):1, for example, 16.4:1.

[0049] Without violating the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0050] The reagents and raw materials used in the present invention are commercially available.

[0051] The positive improvement effect of the present invention is that the enzyme-catalyzed conversion reaction of 5-androstenedione in the method is carried out in an aqueous phase system, thereby avoiding the inactivation of the enzyme, allowing the enzyme to be recycled, greatly reducing the amount of enzyme used, and improving the reaction yield. DETAILED DESCRIPTION

[0052] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0053] Enzymes and defoamers used in the examples:

[0054]

[0055] Example 1: Preparation of 5-AD

[0056] Add potassium tert-butoxide (32.8 g, 0.29 mol) and tert-butanol (156 g, 2.10 mol) to a 250 mL three-necked flask, protect with nitrogen, and dissolve at 60 ° C. Then pour 4-AD (40 g, 0.14 mol) into the bottle, maintain a nitrogen atmosphere, and react at 30 ° C for 1 hour. During the reaction, a reaction quenching system is configured, ice water is maintained at 5 ° C, and 15.4 g glacial acetic acid and 936 mL water are added to the quenching system. The reaction mixture is slowly poured into the quenching system and stirred at low temperature for 0.5 hours. Filter to obtain 5-AD solid. The sample is directly used for the next enzyme catalytic reaction.

[0057] Example 2: Preparation of DHEA

[0058] According to the operation of Example 1, all the obtained 5-AD solids were poured into a 1L three-necked flask, 88g glucose, 16g Triton X-100 were added, and then 0.1M PBS was added to 400mL, stirred evenly, the pH was controlled at 7.0, 2g 3-keto reductase, 0.4g glucose dehydrogenase and 0.08g NAD were added, and the reaction was carried out at 30°C for 4 hours. According to the spot plate results, the substrate was confirmed to be completely converted and collected, and the filtrate was directly filtered and retained for application. The filter cake was washed with water, dried and weighed. Product weight: 36.4g, yield 91%, HPLC purity 97%.

[0059] Example 3: Application of DHEA enzyme catalytic mother solution

[0060] Pour the filtrate in Example 2 into a 1L three-necked flask, add the 5-AD solid obtained by the operation of Example 1, add 88g of glucose, stir evenly, control the pH at 7.0, and react at 30°C for 4 hours. According to the spot plate results, after confirming that the substrate is completely converted, collect the material, filter it directly, and discard the filtrate. Wash the filter cake with water, dry it and weigh it. Product weight: 38.5g, yield 96.3%, HPLC purity 97%.

[0061] Example 4: Preparation of DHEA

[0062] According to the operation of Example 1, all the obtained 5-AD solids were poured into a 1L three-necked flask, 88g glucose, 16g Tween 80 were added, and then 0.1M PBS was added to 400mL, stirred evenly, the pH was controlled at 7.0, 2g 3-ketoreductase, 0.4g glucose dehydrogenase and 0.08g NAD were added, and the reaction was carried out at 30°C for 4 hours. According to the spot plate results, the substrate was confirmed to be completely converted and collected, and the filtrate was directly filtered and retained for application. The filter cake was washed with water, dried and weighed. Product weight: 34g, yield 85%, HPLC purity 97%.

[0063] Example 5: Application of DHEA enzyme catalytic mother solution

[0064] Pour the filtrate in Example 4 into a 1L three-necked flask, add the 5-AD solid obtained by the operation of Example 1, add 88g of glucose, stir evenly, control the pH at 7.0, and react at 30°C for 4 hours. According to the spot plate results, after confirming that the substrate is completely converted, collect the material, filter it directly, and discard the filtrate. Wash the filter cake with water, dry it and weigh it. Product weight: 38.8g, yield 97%, HPLC purity 97%.

[0065] Example 6: Preparation of DHEA

[0066] According to the operation of Example 1, the obtained 5-AD solid was poured into a 1L three-necked flask, and 88g of glucose, 16g of Triton X-100 and 0.8g of composite high-efficiency defoaming agent ( X-298, purchased from Yantai Hengxin Chemical Technology Co., Ltd.), then supplemented with 0.1M PBS to 400mL, stirred evenly, pH controlled at 7.0, added 2g of 3-ketoreductase, 0.4g of glucose dehydrogenase and 0.08g of NAD, and reacted at 30°C for 4 hours. According to the spot plate results, after confirming that the substrate is completely converted, collect the material, filter directly, and retain the filtrate for application. Wash the filter cake with water, dry and weigh. Product weight: 38g, yield 95%, HPLC purity 97%.

[0067] Example 7: Application of DHEA enzyme catalytic mother solution

[0068] Pour the filtrate in Example 6 into a 1L three-necked flask, add the 5-AD solid obtained by the operation of Example 1, add 88g of glucose, stir evenly, control the pH at 7.0, and react at 30°C for 4 hours. According to the spot plate results, after confirming that the substrate is completely converted, collect the material, filter directly, and retain the filtrate for reuse. Wash the filter cake with water, dry and weigh it. Product weight: 39.2g, yield 98%, HPLC purity 97%.

[0069] Example 8: Application of DHEA enzyme catalytic mother solution

[0070] The filtrate obtained according to Example 7 was poured into a 1L three-necked flask, and the 5-AD solid obtained according to Example 1 was added, 88g of glucose, 1g of 3-ketoreductase, 0.2g of glucose dehydrogenase and 0.04g of NAD were added, stirred evenly, the pH was controlled at 7.0, and the reaction was carried out at 30°C for 12 hours. According to the spot plate results, the substrate was confirmed to be completely converted, and the material was collected and directly filtered, and the filtrate was discarded. The filter cake was washed with water, dried and weighed. Product weight: 39.3g, yield 98.3%, HPLC purity 97%.

[0071] Comparative Example 1: Preparation of DHEA (refer to the example of CN106086148B)

[0072] The 5-AD solid obtained in Example 1 was dissolved in 200 mL of 2-methyltetrahydrofuran, and 200 mL of 0.1 M pH 6.5 PBS solution was added and stirred. 88 g of glucose, 2 g of 3-ketoreductase, 0.4 g of glucose dehydrogenase and 0.08 g of NAD were added in sequence, and the reaction was carried out at 30°C for 4 hours. According to the spot plate results, the substrate was completely converted and the material was collected. It was extracted twice with 200 mL of ethyl acetate, the aqueous phase was discarded, the extracts were combined and concentrated until there was no droplet, and the solid was dried and weighed. Product weight: 28.5 g, yield 71.25%, HPLC purity 96%.

[0073] Comparative Example 2: Preparation of DHEA

[0074] According to the operation of Example 1, all the obtained 5-AD solids were poured into a 1L three-necked flask, 88g of glucose and 16g of soybean oil were added, and then 0.1M PBS was added to 400mL, stirred evenly, the pH was controlled at 7.0, 2g of 3-keto reductase, 0.4g of glucose dehydrogenase and 0.08g of NAD were added, and the reaction was carried out at 30°C for 4 hours. According to the spot plate results, after confirming that the substrate was completely converted, the material was collected and directly filtered, and the filtrate was retained for application. The filter cake was washed with water, dried and weighed. Product weight: 23.2g, yield 58%, HPLC purity 65%.

[0075] Comparative Example 3: Preparation of DHEA

[0076] According to the operation of Example 1, all the obtained 5-AD solids were poured into a 1L three-necked flask, 88g of glucose and 16g of phospholipids were added, and then 0.1M PBS was added to 400mL, stirred evenly, the pH was controlled at 7.0, 2g of 3-ketoreductase, 0.4g of glucose dehydrogenase and 0.08g of NAD were added, and the reaction was carried out at 30°C for 4 hours. According to the results of the spot plate, the substrate was confirmed to be completely converted and the material was collected and directly filtered, and the filtrate was retained for application. The filter cake was washed with water, dried and weighed. Product weight: 28g, yield 70%, HPLC purity 82%.

Claims

1. A method for preparing a compound as shown in formula 3, characterized in that: The method comprises the following steps: in an aqueous buffer system, in the presence of a nonionic auxiliary agent, glucose, 3-ketoreductase, glucose dehydrogenase and NAD, subjecting the compound represented by Formula 2 to a reduction reaction as shown below, to obtain a compound represented by Formula 3; the nonionic auxiliary agent is a polyoxyethylene ether auxiliary agent and / or a polysorbate auxiliary agent; The polyoxyethylene ether auxiliary agent is Triton X-100; The polysorbate adjuvant is Tween 80; The mass ratio of the compound represented by formula 2 to the nonionic auxiliary agent is (2-3):

1.

2. The method for preparing the compound as shown in Formula 3 according to claim 1, characterized in that: The method for preparing the compound as shown in Formula 3 satisfies one or more of the following conditions: (1) In the reduction reaction, the buffer system is a phosphate buffer solution; (2) In the reduction reaction, the pH of the buffer system is 6.0 to 7.0; (3) In the reduction reaction, the mass volume ratio of the compound represented by Formula 2 to the buffer system is 100 mg / mL to 200 mg / mL; (4) In the reduction reaction, the reaction is carried out in the presence of a defoaming agent; (5) In the reduction reaction, the mass ratio of the compound represented by formula 2 to the glucose is 1:(2-3); (6) In the reduction reaction, the mass ratio of the compound represented by Formula 2 to the 3-ketoreductase is (15-22):1; (7) In the reduction reaction, the mass ratio of the 3-ketoreductase to the glucose dehydrogenase is (3-7):1; (8) In the reduction reaction, the mass ratio of the 3-ketoreductase to the NAD is (20-30):1; In the reduction reaction described in (9), the reaction temperature is 20 to 40°C.

3. The method for preparing the compound as shown in Formula 3 according to claim 2, characterized in that: The method for preparing the compound as shown in Formula 3 satisfies one or more of the following conditions: (1) In the reduction reaction, the phosphate is one or more of sodium dihydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate and dipotassium hydrogen phosphate; (2) In the reduction reaction, the pH of the buffer system is 6.5 to 7.0; (3) In the reduction reaction, the mass volume ratio of the compound represented by Formula 2 to the buffer system is 140 mg / mL to 160 mg / mL; (4) In the reduction reaction, the mass ratio of the compound represented by formula 2 to the nonionic auxiliary agent is (2.2-2.5):1; (5) In the reduction reaction, the defoaming agent is one or more of a polysiloxane defoaming agent, a polyoxypropylene glycerol ether defoaming agent and a silicone ether defoaming agent; (6) In the reduction reaction, the mass ratio of the compound represented by formula 2 to the defoaming agent is (30-60):1; (7) In the reduction reaction, the mass ratio of the compound represented by formula 2 to the glucose is 1:(2.2-2.5); (8) In the reduction reaction, the mass ratio of the compound represented by formula 2 to the 3-ketoreductase is (18-20):1; (9) In the reduction reaction, the mass ratio of the 3-ketoreductase to the glucose dehydrogenase is 5:1; (10) In the reduction reaction, the mass ratio of the 3-ketoreductase to the NAD is 25:1; In the reduction reaction described in (11), the reaction temperature is 30°C.

4. The method for preparing the compound as shown in Formula 3 according to claim 3, characterized in that: The method for preparing the compound as shown in Formula 3 satisfies one or more of the following conditions: (1) In the reduction reaction, the pH of the buffer system is 7.0; (2) In the reduction reaction, the defoaming agent is a silicone ether defoaming agent; In the reduction reaction described in (3), the mass ratio of the compound represented by formula 2 to the defoaming agent is (45-50):

1.

5. The method for preparing the compound as shown in Formula 3 according to claim 4, characterized in that: The method for preparing the compound as shown in Formula 3 satisfies one or more of the following conditions: (1) The NAD described is NAD (CAS 53-84-9) produced by Suzhou Hanzyme Biotechnology Co., Ltd.; (2) The defoamer is produced by Yantai Hengxin Chemical Technology Co., Ltd. X-298 composite high-efficiency defoaming agent; (3) After the reaction is completed, the reaction is directly filtered and the filtrate is recycled for the above reaction; The raw materials for the reaction in (4) are the nonionic auxiliary agent, glucose, 3-ketoreductase, glucose dehydrogenase and NAD, and the aqueous buffer system, or the nonionic auxiliary agent, defoaming agent, glucose, 3-ketoreductase, glucose dehydrogenase and NAD, and the aqueous buffer system.

6. The method for preparing the compound of formula 3 according to claim 2, characterized in that: The preparation method of the compound shown in Formula 3 is Scheme 1 or Scheme 2: Solution 1: The buffer system is a phosphate buffer solution; The pH of the buffer system is 7.0; The mass volume ratio of the compound represented by formula 2 to the buffer system is 140 mg / mL to 160 mg / mL; The non-ionic auxiliary agent is Triton X-100 and / or Tween 80; The mass ratio of the compound represented by formula 2 to the nonionic auxiliary agent is (2.2-2.5):1; The mass ratio of the compound represented by formula 2 to the glucose is 1:(2.2-2.5); The mass ratio of the compound represented by formula 2 to the 3-ketoreductase is (18-20):1; The mass ratio of the 3-ketoreductase to the glucose dehydrogenase is 5:1; The mass ratio of the 3-ketoreductase to the NAD is 25:1; The reaction temperature is 30°C; Solution 2 The buffer system is a phosphate buffer solution; The pH of the buffer system is 7.0; The mass volume ratio of the compound represented by formula 2 to the buffer system is 140 mg / mL to 160 mg / mL; The non-ionic auxiliary agent is Triton X-100; The mass ratio of the compound represented by formula 2 to the nonionic auxiliary agent is (2.2-2.5):1; The defoamer is a silicone ether defoamer; The mass ratio of the compound represented by formula 2 to the defoaming agent is (45-50):1; The mass ratio of the compound represented by formula 2 to the glucose is 1:(2.2-2.5); The mass ratio of the compound represented by formula 2 to the 3-ketoreductase is (18-20):1; The mass ratio of the 3-ketoreductase to the glucose dehydrogenase is 5:1; The mass ratio of the 3-ketoreductase to the NAD is 25:1; The reaction temperature is 30°C.

7. The method for preparing the compound of formula 3 according to claim 5, characterized in that: The recycling method comprises the following steps: after the reduction reaction is completed, the reaction system is filtered, and in the filtrate, in the presence of glucose, 3-ketoreductase, glucose dehydrogenase and NAD, when the pH value is 7.0, the compound represented by formula 2 is subjected to the following reduction reaction to obtain a compound represented by formula 3; 8. The method for preparing the compound of formula 3 according to claim 7, characterized in that: In the recycling step, the definitions and conditions of the compound represented by formula 2, glucose, 3-ketoreductase, glucose dehydrogenase and NAD are as described in any one of claims 1-6.

9. The method for preparing the compound as shown in Formula 3 according to any one of claims 1 to 7, characterized in that: The method further comprises the following steps: in a protective atmosphere, in a solvent, in the presence of a base, subjecting the compound represented by Formula 1 to a double bond transposition reaction as shown below, to obtain a compound represented by Formula 2; 10. The method for preparing the compound of formula 3 according to claim 9, characterized in that: The method for preparing the compound as shown in Formula 3 satisfies one or more of the following conditions: (1) In the double bond transposition reaction, the protective atmosphere is an inert gas; (2) In the double bond transposition reaction, the solvent is an alcohol solvent; (3) In the double bond transposition reaction, the mass ratio of the compound represented by Formula 1 to the solvent is 1:(3-4); (4) In the double bond transposition reaction, the base is an organic base; (5) In the double bond transposition reaction, the mass ratio of the compound represented by Formula 1 to the base is (1 to 1.5):1; In the double bond transposition reaction described in (6), the reaction temperature is 20 to 40°C.

11. The method for preparing the compound of formula 3 according to claim 10, characterized in that: The method for preparing the compound as shown in Formula 3 satisfies one or more of the following conditions: (1) In the double bond transposition reaction, the protective atmosphere is nitrogen; (2) In the double bond transposition reaction, the solvent is tert-butyl alcohol; (3) In the double bond transposition reaction, the mass ratio of the compound represented by Formula 1 to the solvent is 1:3.9; (4) In the double bond transposition reaction, the base is potassium tert-butoxide; (5) In the double bond transposition reaction, the mass ratio of the compound represented by Formula 1 to the base is 1.2:1; In the double bond transposition reaction described in (6), the reaction temperature is 30°C.

12. The method for preparing the compound of formula 3 according to claim 10, characterized in that: The double bond transposition reaction further includes post-treatment, and the post-treatment includes the following steps: after the double bond transposition reaction is completed, the reaction system is quenched and filtered to obtain the compound shown in formula 2.

13. The method for preparing the compound of formula 3 according to claim 12, characterized in that: The preparation method of the compound shown in Formula 3 satisfies the following conditions: (1) The quenching is to add the reaction system into the quenching system; (2) The quenching system is a mixed solution of acid and water.

14. The method for preparing the compound of formula 3 according to claim 13, characterized in that: The acid is an organic acid.

15. The method for preparing the compound of formula 3 according to claim 13, characterized in that: The mass ratio of the acid to the water is (15-20):

1.

16. The method for preparing the compound of formula 3 according to claim 13, characterized in that: The preparation method of the compound shown in Formula 3 satisfies the following conditions: (1) The acid is glacial acetic acid; The mass ratio of the acid described in (2) to the water described is 16.4:1.

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