Method for purifying biotin precursor and prepared biotin precursor crystals

Abstract

The present invention relates to the field of biotin preparation and discloses a method for refining a biotin precursor and the resulting biotin precursor crystals. The method comprises: (1) passing a biotin precursor solution through a resin containing ionic groups and non-polar groups at a rate of 1-30 BV / h to obtain material A; and (2) crystallizing material A to obtain biotin precursor crystals. The method can produce a biotin precursor of relatively high purity and has the advantages of a simple process route and low production cost.

Description

Technical Field

[0001] The present invention relates to the field of biotin preparation, and in particular to a method for refining a biotin precursor and the prepared biotin precursor crystals. Background Art

[0002] Biotin, also known as VH or vitamin B7, is an essential nutrient for the human body. As the last vitamin to be fully industrialized, biotin's synthesis process is lengthy, with numerous intermediates, low yields, numerous side reactions, and a high concentration of impurities. Current industrial production methods for impurity removal still primarily rely on extraction, which has limited purification effectiveness and carries over a significant amount of impurities to the next step, significantly reducing the efficiency of subsequent synthesis reactions and increasing unit product consumption. Some companies have already made corresponding improvements, employing crystallization techniques in the biotin precursor preparation step to improve raw material purity. However, the process still requires multiple steps, including acidification, alkalization, and secondary acidification, making it cumbersome, inefficient, and prone to emulsification issues.

[0003] Based on this, there is an urgent need to develop a simple, efficient and low-cost biotin precursor purification process. Summary of the Invention

[0004] The present invention aims to overcome the complex and inefficient purification processes of biotin precursors in existing technologies by providing a method for purifying a biotin precursor and the resulting biotin precursor crystals. The method can produce a biotin precursor of high purity, while also offering the advantages of a simple process and low production costs.

[0005] In order to achieve the above object, the present invention provides a method for purifying a biotin precursor, which comprises:

[0006] (1) passing a biotin precursor solution through a resin containing ionic groups and non-polar groups at a rate of 1-30 BV / h to obtain material A;

[0007] (2) Crystallizing material A to obtain biotin precursor crystals.

[0008] Preferably, the rate at which the biotin precursor solution passes through the resin is 2-20 BV / h.

[0009] Preferably, the ionic groups are sulfonic acid groups and / or quaternary ammonium groups.

[0010] Preferably, the non-polar group is a C4-C18 aliphatic group and / or a C10-C30 aromatic group.

[0011] Preferably, the particle size of the resin is 20-400 mesh, preferably 100-250 mesh.

[0012] The second aspect of the present invention provides a biotin precursor crystal prepared by the method described in the first aspect.

[0013] Through the above technical solution, the beneficial effects of the present invention include:

[0014] 1. The method of the present invention can produce a high-purity biotin precursor, which is beneficial for subsequent reactions and reduces the use of raw materials. Furthermore, the method has a simple process route, which can reduce the total time of the biotin production process, improve production efficiency, and facilitate industrial scale-up.

[0015] 2. In the method of the present invention, the resin can be recycled and the solvent can be recycled during the production process, which can reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic flow chart of the biotin precursor purification method of the present invention. DETAILED DESCRIPTION

[0017] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0018] One aspect of the present invention provides a method for refining a biotin precursor, the method comprising:

[0019] (1) passing a biotin precursor solution through a resin containing ionic groups and non-polar groups at a rate of 1-30 BV / h to obtain material A;

[0020] (2) Crystallizing material A to obtain biotin precursor crystals.

[0021] In the present invention, BV refers to the volume of the chromatography column filled with the filler layer.

[0022] Specifically, the BV of a resin refers to the volume of a resin chromatography column filled with resin.

[0023] The BV in activated carbon refers to the volume of the activated carbon column filled with activated carbon.

[0024] In the present invention, the volume of the filler layer of the resin chromatography column and the activated carbon column can be appropriately selected according to actual conditions.

[0025] The present invention has no particular limitation on the method of resin column packing, and the method can be carried out according to conventional methods in the art. The present invention uses wet column packing as an example.

[0026] According to the present invention, preferably, the rate at which the biotin precursor solution passes through the resin is 2-20 BV / h. For example, 2 BV / h, 3 BV / h, 4 BV / h, 5 BV / h, 6 BV / h, 7 BV / h, 8 BV / h, 9 BV / h, 10 BV / h, 11 BV / h, 12 BV / h, 13 BV / h, 14 BV / h, 15 BV / h, 16 BV / h, 17 BV / h, 18 BV / h, 19 BV / h, 20 BV / h, and any value within the range formed by any two of these values. This preferred embodiment allows for efficient and convenient separation of the product and impurities, improving product quality, reducing operational steps, and increasing production efficiency.

[0027] According to the present invention, preferably, the ionic groups are sulfonic acid groups and / or quaternary ammonium groups. Using this preferred embodiment, the ionic groups can synergistically act with the non-polar groups to effectively improve the adsorption effect.

[0028] According to the present invention, preferably, the non-polar group is a C4-C18 aliphatic group and / or a C10-C30 aromatic group. Using this preferred embodiment, the synergistic effect with the ionic group can effectively improve the adsorption effect.

[0029] According to the present invention, preferably, the particle size of the resin is 20-400 mesh, preferably 100-250 mesh, for example, 20 mesh, 50 mesh, 100 mesh, 150 mesh, 200 mesh, 250 mesh, 300 mesh, 350 mesh, 400 mesh, and any value in the range formed by any two of these values.

[0030] By adopting this preferred embodiment, on the one hand, the resin is ensured to have a good adsorption effect, and on the other hand, the biotin precursor solution is allowed to pass through at a higher flow rate, thereby reducing production time and saving costs.

[0031] The present invention allows for a wide range of resin types; any resin that meets the above requirements can be used. Preferably, the resin is selected from at least one of TOYOPEARL MX-Trp-650M resin, UniBPC-SCX resin, and UniBPC-WCX resin. All of these resins are commercially available.

[0032] According to the present invention, preferably, the mass fraction of the biotin precursor solution is 10-30%.

[0033] According to the present invention, preferably, the crystallization in step (2) is cooling crystallization.

[0034] According to the present invention, preferably, the crystallization includes: cooling material A to a crystallization temperature and then maintaining it at a constant temperature, wherein the crystallization temperature is -50 to 0°C, preferably -30 to -5°C, such as -50°C, -45°C, -40°C, -35°C, -30°C, -25°C, -20°C, -15°C, -10°C, -5°C, 0°C, and any value in the range consisting of any two of these values; the constant temperature time is 0.5-6h, preferably 1-4h, such as 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, and any value in the range consisting of any two of these values. Using this preferred embodiment, the prepared crystals have high purity, good crystal form, and are easy to separate from the solvent.

[0035] According to the present invention, preferably, the cooling rate is 0.1-3°C / min, preferably 0.2-2°C / min. For example, 0.1°C / min, 0.2°C / min, 0.3°C / min, 0.4°C / min, 0.5°C / min, 0.6°C / min, 0.7°C / min, 0.8°C / min, 0.9°C / min, 1°C / min, 1.1°C / min, 1.2°C / min, 1.3°C / min, 1.4°C / min, 1.5°C / min, 1.6°C / min, 1.7°C / min, 1.8°C / min, 1.9°C / min, 2°C / min, 2.1°C / min, 2.2°C / min, 2.3°C / min, 2.4°C / min, 2.5°C / min, 2.6°C / min, 2.7°C / min, 2.8°C / min, 2.9°C / min, 3°C / min, and any value in the range consisting of any two of these values. Adopting this preferred embodiment is more conducive to crystallization.

[0036] According to the present invention, preferably, the crystallization is carried out under stirring, and the rotating speed of the stirring is 1-150rpm, preferably 5-50rpm. For example, 1rpm, 2rpm, 5rpm, 10rpm, 15rpm, 20rpm, 25rpm, 30rpm, 35rpm, 40rpm, 45rpm, 50rpm, 60rpm, 70rpm, 80rpm, 90rpm, 100rpm, 110rpm, 120rpm, 130rpm, 140rpm, 150rpm, and any value in the range consisting of any two of these values. Adopting this preferred embodiment, the crystallization rate can be accelerated while ensuring the quality of the crystals.

[0037] The present invention has no particular limitation on the source of the biotin precursor solution, and the biotin precursor solution can be prepared by various conventional methods in the art. To more clearly illustrate the preparation of the biotin precursor, a specific preparation method is provided, but the present invention is not limited thereto.

[0038] According to the present invention, preferably, the method for preparing the biotin precursor solution comprises:

[0039] (a) reacting magnesium powder, 1,4-dichlorobutane and a first solvent in the presence of an initiator under anhydrous and oxygen-free conditions to obtain a Grignard reagent;

[0040] (b) subjecting the thiolactone, the Grignard reagent obtained in step (a), and carbon dioxide to a double addition reaction;

[0041] (c) in the presence of a second solvent, subjecting the reaction product of step (b), water and an acid to a hydrolysis and acidification reaction to obtain a biotin precursor solution.

[0042] The reaction conditions of step (a) of the present invention are relatively wide and can be carried out according to conventional methods in the art. Preferably, the reaction conditions of step (a) include: a temperature of 65-75°C, preferably 65-70°C; and a reaction time of 3-10 hours, preferably 3-8 hours.

[0043] According to the present invention, preferably, the molar ratio of the magnesium powder, 1,4-dichlorobutane, the first solvent and the initiator is 1:0.2-1:10-20:0.001-0.1.

[0044] The present invention has a wide range of selection for the type of initiator. Preferably, the initiator is elemental iodine or a Grignard reagent.

[0045] The present invention has a wide range of choices for the first solvent, and can be various organic solvents commonly used in the art. Preferably, the first solvent is selected from at least one of tetrahydrofuran, 2-methyltetrahydrofuran, and diethyl ether.

[0046] In the present invention, the first solvent can be recovered and reused.

[0047] According to the present invention, preferably, the double addition reaction in step (b) comprises: firstly performing a first reaction on the thiolactone and the Grignard reagent obtained in step (a), and then performing a second reaction on the thiolactone and carbon dioxide.

[0048] The present invention has no particular limitation on the conditions of the first reaction and the second reaction and the amount of each substance used. They can be carried out according to conventional methods in the art and are not limited herein.

[0049] The thiolactone of the present invention can be a conventional choice in the art. Preferably, the thiolactone is (3aS,6aR)-1,3-dibenzyl-tetrahydro-4H-thieno[3,4-d]imidazole-2,4-(1H)-dione.

[0050] According to a specific embodiment of the present invention, the thiolactone is provided in the form of a mixed solution, and the solvent of the mixed solution is selected from at least one of tetrahydrofuran, 2-methyltetrahydrofuran and diethyl ether.

[0051] Preferably, the solvent of the mixed solution is the same as the first solvent.

[0052] Preferably, the mass fraction of thiolactone in the thiolactone mixed solution is 10-20%. This preferred embodiment can ensure the smooth progress of the double addition reaction and save the amount of solvent, thereby saving costs.

[0053] The present invention has a wide range of conditions for the hydrolysis and acidification reaction, and can be carried out according to conventional methods in the art. Preferably, the hydrolysis and acidification reaction conditions in step (c) include: a temperature of 20-50°C, preferably 30-50°C; and a time of 1-6 hours, preferably 2-5 hours.

[0054] According to the present invention, preferably, the molar ratio of the reaction product of step (b), water, acid and the second solvent is 1:10-80:10-80:5-40.

[0055] The present invention has a wide range of choices for the type of acid, which can be a conventional choice in the art. Preferably, the acid is hydrochloric acid and / or sulfuric acid.

[0056] The second solvent of the present invention is a water-insoluble solvent, and the bioprecursor can be dissolved in the second solvent. Preferably, the second solvent is selected from at least one of toluene, ethyl acetate and chloroform.

[0057] In the present invention, the bioprogenitor solution is a solution obtained by dissolving the bioprogenitor in the second solvent.

[0058] According to a specific embodiment of the present invention, the product obtained by the hydrolysis and acidification reaction is allowed to stand and separate into layers to obtain a bioprotokinase solution.

[0059] Preferably, the method further comprises: performing solid-liquid separation on the crystallization product of step (2) to obtain biotin precursor crystals and crystallization mother liquor respectively.

[0060] The present invention has no particular limitation on the solid-liquid separation method, which can be performed by referring to conventional technical means in the art. The present invention uses filtration as an example.

[0061] Preferably, the biotin precursor crystal is used as a raw material for preparing biotin.

[0062] Preferably, the crystallization mother liquor is adsorbed by an activated carbon column. For economic considerations, in the present invention, the crystallization mother liquor after adsorption by activated carbon can be reused as the second solvent.

[0063] According to the present invention, preferably, the method further comprises: desorbing the activated carbon column after adsorption.

[0064] According to the present invention, preferably, the desorption conditions include: temperature of 60-100° C. and pH of 3-7.

[0065] According to the present invention, preferably, the desorption agent is an organic solvent, preferably at least one selected from toluene, ethyl acetate and chloroform.

[0066] Preferably, the desorbing agent is the same as the second solvent.

[0067] Preferably, the pH is adjusted using acid (the type of acid is the same as the type of acid mentioned above).

[0068] The present invention has no particular limitation on the amount of the desorption agent, as long as the residual biotin precursor is completely eluted. Preferably, the amount of the desorption agent is 5-25 BV.

[0069] In the present invention, the concentration of the biotin precursor is measured by liquid chromatography.

[0070] For economic considerations, in the present invention, the material C obtained after desorbing the activated carbon can be reused as the second solvent.

[0071] Preferably, the method further comprises: incinerating the desorbed activated carbon. In order not to affect production, the present invention further comprises a spare activated carbon column connected in parallel with the activated carbon column.

[0072] Preferably, the method further comprises: rinsing the resin with a second solvent before using the resin.

[0073] According to the present invention, preferably, the method further comprises: eluting the resin after adsorption in step (1).

[0074] According to the present invention, preferably, the elution temperature is 40-80°C.

[0075] According to the present invention, preferably, the eluting agent is a non-polar organic solvent, preferably at least one selected from toluene, ethyl acetate and chloroform.

[0076] Preferably, the eluting agent is the same as the second solvent.

[0077] The present invention has no particular limitation on the amount of the eluting agent, as long as all the biotin precursor is eluted.

[0078] According to the present invention, preferably, the flow rate of the eluting agent is 0.5-10 BV / h.

[0079] Preferably, the material B obtained by eluting the resin is crystallized.

[0080] According to the present invention, preferably, the method further comprises: regenerating the eluted resin. The resin of the present invention can be reused after regeneration, which is beneficial to reducing production costs.

[0081] The regeneration agent of the present invention is helpful for removing impurities adsorbed by the resin. According to the present invention, preferably, the regeneration agent is n-hexane or petroleum ether.

[0082] In the present invention, the terms "first" and "second" do not limit the substances and operations, but are only used to distinguish substances introduced in different steps and operations performed in different stages.

[0083] The second aspect of the present invention provides a biotin precursor crystal prepared by the method described in the first aspect.

[0084] The present invention will be described in detail below through examples.

[0085] TOYOPEARL MX-Trp-650M resin is a commercial product of Tosoh (Shanghai) Biotechnology Co., Ltd. with the brand number 0022817 and a particle size of 200 mesh;

[0086] UniBPC-SCX resin is a commercial product of Suzhou Nawei Technology Co., Ltd. with the brand name UB60SC and a particle size of 240-250 mesh;

[0087] Nuvia cPrime resin is a commercial product of Bio-Rad Corporation in the United States with the brand name Nuvia cPrime, and has a particle size of 160-170 mesh.

[0088] Example 1

[0089] Now combined Figure 1To better illustrate the method of the present invention, 1,4-dichlorobutane and magnesium turnings were reacted in an anhydrous and oxygen-free environment using tetrahydrofuran as the solvent and a Grignard reagent seed as the initiator at 68°C for 4 hours to prepare a Grignard reagent. The molar ratio of 1,4-dichlorobutane, magnesium turnings, tetrahydrofuran, and Grignard reagent seed was 1:0.5:15:0.005. A 16% by mass thiolactone / tetrahydrofuran mixed solution was added dropwise to the Grignard reagent, and the reaction was continued at -30°C for 2.5 hours. CO₂ was then introduced for a double addition reaction, and the reaction was continued for 1 hour. The mass ratio of the Grignard reagent, thiolactone / tetrahydrofuran mixed solution, and CO₂ was 1:1.02:0.05. The tetrahydrofuran solvent was recovered, and then hydrochloric acid, water, and the toluene solution (materials B and C) were added. The mixture was reacted at 40°C for 3 hours. The molar ratio of the double addition reaction product, water, hydrochloric acid, and toluene solution was 1:30:50:30. After standing and separating the layers, a biotin precursor solution with a mass fraction of 27.5% was obtained.

[0090] 100 mL of TOYOPEARL MX-Trp-650M resin was wet-packed into a column, then rinsed with 5 BV of toluene solvent to reach equilibrium. The biotin precursor solution was passed through the resin at a flow rate of 8 BV / h to obtain material A. The residual biotin precursor solution in the column was eluted with 4 BV of toluene solvent to obtain material B. Material A and material B were then cooled to -5°C at a rate of 1°C / min for crystallization, with stirring at 50 rpm. Biotin precursor crystals precipitated after 1 hour, with a molar yield of 85%. The crystallization mother liquor was filtered to obtain material W. After adsorption on the activated carbon column, the crystallization mother liquor was applied to the hydrochloric acid hydrolysis step described above.

[0091] The adsorbed resin column was eluted with 50 BV of toluene at 70°C at a flow rate of 5 BV / h, followed by 4 BV of n-hexane to remove impurities. The adsorbed activated carbon was then rinsed with 10 BV of toluene at 80°C, pH 4, and the washed material C was used in the hydrochloric acid hydrolysis step described above.

[0092] Example 2

[0093] The Grignard reagent was prepared by reacting 1,4-dichlorobutane with magnesium turnings in an anhydrous and oxygen-free environment using tetrahydrofuran as the solvent and a Grignard reagent seed as the initiator at 68°C for 4 hours. The molar ratio of 1,4-dichlorobutane, magnesium turnings, tetrahydrofuran, and seed was 1:0.5:15:0.005. A 16% thiolactone / tetrahydrofuran mixed solution was added dropwise to the Grignard reagent, and the reaction was continued at -30°C for 2.5 hours. CO2 was then introduced for a double addition reaction, which was continued for 1 hour. The mass ratio of the Grignard reagent, thiolactone / tetrahydrofuran mixed solution, and CO2 was 1:1.02:0.05. The tetrahydrofuran solvent was recovered, and then hydrochloric acid, water, and the toluene solution (materials B and C) were added. The mixture was reacted at 40°C for 3 hours. The molar ratio of the double addition reaction product, water, hydrochloric acid, and toluene solution was 1:30:50:26. After standing and separating, a biotin precursor solution with a mass fraction of 32.3% was obtained.

[0094] 100 mL of UniBPC-SCX resin was wet-packed into a column. 5 BV of toluene was rinsed to equilibrium. The biotin precursor solution was passed through the resin at a flow rate of 8 BV / h to obtain Material A. The residual biotin precursor solution in the column was eluted with 4 BV of toluene to obtain Material B. Material A and Material B were then cooled to -10°C at a rate of 1.5°C / min for crystallization with stirring at 30 rpm. Biotin precursor crystals precipitated after 1.5 hours, with a molar yield of 86%. The mother liquor was filtered to obtain the crystallization product. After adsorption on the activated carbon column, the mother liquor was used as Material W in the hydrochloric acid hydrolysis step described above.

[0095] The adsorbed resin column was eluted with 80°C toluene at a flow rate of 2 BV / h for 30 BV. The adsorbed resin column was then washed with 4 BV of n-hexane to remove impurities. The adsorbed activated carbon was then rinsed with 15 BV of toluene at 70°C and pH 6. The rinsed material C was then used in the hydrochloric acid hydrolysis step described above.

[0096] Example 3

[0097] The Grignard reagent was prepared by reacting 1,4-dichlorobutane with magnesium turnings in an anhydrous and oxygen-free environment using tetrahydrofuran as the solvent and a Grignard reagent seed as the initiator at 68°C for 4 hours. The molar ratio of 1,4-dichlorobutane, magnesium turnings, tetrahydrofuran, and Grignard reagent seed was 1:0.5:15:0.005. A 16% thiolactone / tetrahydrofuran mixed solution was added dropwise to the Grignard reagent, and the reaction was continued at -30°C for 2.5 hours. CO2 was then introduced for a double addition reaction, which was continued for 1 hour. The mass ratio of the Grignard reagent, thiolactone / tetrahydrofuran mixed solution, and CO2 was 1:1.02:0.05. The tetrahydrofuran solvent was recovered, and then hydrochloric acid, water, and the toluene solution (materials B and C) were added. The mixture was reacted at 40°C for 3 hours. The molar ratio of the double addition reaction product, water, hydrochloric acid, and toluene solution was 1:30:50:20. After standing and separating, a biotin precursor solution with a mass fraction of 35.8% was obtained.

[0098] 100 mL of UniBPC-SCX resin was wet-packed into a column. 5 BV of toluene was rinsed to equilibrium. The biotin precursor solution was passed through the resin at a flow rate of 10 BV / h to obtain Material A. The residual biotin precursor solution in the column was eluted with 4 BV of toluene to obtain Material B. Material A and Material B were then cooled to -5°C at a rate of 0.5°C / min for crystallization with stirring at 50 rpm. Biotin precursor crystals precipitated after 1 hour, with a molar yield of 85%. The mother liquor was filtered to obtain the crystallization product. Material W, after adsorption on the activated carbon column, was applied to the hydrochloric acid hydrolysis step described above.

[0099] The adsorbed resin column was eluted with 20 BV of toluene at 60°C at a flow rate of 3 BV / h. Then, the adsorbed resin column was washed with 4 BV of petroleum ether to remove impurities. The adsorbed activated carbon was rinsed with 8 BV of toluene at 90°C and pH 5. The rinsed material C was then used in the hydrochloric acid hydrolysis step described above.

[0100] Example 4

[0101] The Grignard reagent was prepared by reacting 1,4-dichlorobutane with magnesium turnings in an anhydrous and oxygen-free environment using tetrahydrofuran as the solvent and a Grignard reagent seed as the initiator at 68°C for 4 hours. The molar ratio of 1,4-dichlorobutane, magnesium turnings, tetrahydrofuran, and Grignard reagent seed was 1:0.5:15:0.005. A 16% thiolactone / tetrahydrofuran mixed solution was added dropwise to the Grignard reagent, and the reaction was continued at -30°C for 2.5 hours. CO2 was then introduced for a double addition reaction, which was continued for 1 hour. The mass ratio of the Grignard reagent, thiolactone / tetrahydrofuran mixed solution, and CO2 was 1:1.02:0.05. The tetrahydrofuran solvent was recovered, and then hydrochloric acid, water, and the toluene solution (materials B and C) were added. The mixture was reacted at 40°C for 3 hours. The molar ratio of the double addition reaction product, water, hydrochloric acid, and toluene solution was 1:30:50:30. After standing and separating the layers, a biotin precursor solution with a mass fraction of 27.5% was obtained.

[0102] Take 100mL TOYOPEARL MX-Trp-650M resin, wet pack the column, and then rinse 5BV with toluene solvent to reach equilibrium. Pass the biotin precursor solution through the resin at a flow rate of 4BV / h to obtain material A. Use 4BV of toluene solvent to elute the residual biotin precursor solution in the column to obtain material B. Then, cool material A and material B to -15°C at a rate of 0.8°C / min for crystallization, with a stirring speed of 30rpm. After 2h, biotin precursor crystals precipitate, and the molar yield of biotin precursor crystals is 92%. Filter to obtain the crystallization mother liquor. After adsorption of the crystallization mother liquor on the activated carbon column, apply material W to the previous hydrochloric acid hydrolysis step.

[0103] The adsorbed resin column was eluted with 80°C toluene at a flow rate of 1 BV / h for 20 BV. The adsorbed resin column was then washed with 4 BV of petroleum ether to remove impurities. The adsorbed activated carbon was then rinsed with 15 BV of toluene at 70°C and pH 5. The rinsed material C was then used in the hydrochloric acid hydrolysis step described above.

[0104] Example 5

[0105] A Grignard reagent was prepared by reacting 1,4-dichlorobutane with magnesium turnings in an anhydrous and oxygen-free environment using tetrahydrofuran as the solvent and seeds as the initiator at 68°C for 4 hours. The molar ratio of 1,4-dichlorobutane, magnesium turnings, tetrahydrofuran, and seeds was 1:0.5:15:0.005. A 16% thiolactone / tetrahydrofuran mixture was added dropwise to the Grignard reagent, and the reaction was continued at -30°C for 2.5 hours. CO₂ was then introduced for a double addition reaction, which was continued for 1 hour. The mass ratio of the Grignard reagent, thiolactone / tetrahydrofuran mixture, and CO₂ was 1:1.02:0.05. The tetrahydrofuran solvent was recovered, and hydrochloric acid, water, and the recycled toluene solution (materials B and C) were added. The reaction was continued at 40°C for 3 hours. The molar ratio of the double addition reaction product, water, hydrochloric acid, and recycled toluene solution was 1:30:50:28. The solution was allowed to stand for separation to obtain a biotin precursor solution with a mass fraction of 28.5%.

[0106] 100 mL of UniBPC-SCX resin was wet-packed into a column, then rinsed with 5 BV of toluene solvent to reach equilibrium. The biotin precursor solution was passed through the resin at a flow rate of 15 BV / h to obtain material A. The residual biotin precursor solution in the column was eluted with 4 BV of toluene solvent to obtain material B. Material A and material B were then cooled to -25°C at a rate of 1.5°C / min for crystallization, with a stirring speed of 60 rpm. Biotin precursor crystals precipitated after 2 hours, with a molar yield of 80%. The crystallization mother liquor was filtered to obtain material W. After adsorption on the activated carbon column, the crystallization mother liquor was applied to the hydrochloric acid hydrolysis step described above.

[0107] The adsorbed resin column was eluted with 80°C toluene at a flow rate of 4 BV / h for 30 BV. The adsorbed resin column was then washed with 5 BV of n-hexane to remove impurities. The adsorbed activated carbon was then rinsed with 15 BV of toluene at 70°C and pH 5. The rinsed material C was then used in the hydrochloric acid hydrolysis step described above.

[0108] Example 6

[0109] The method of Example 4 was followed, except that the TOYOPEARL MX-Trp-650M resin was replaced with an equal volume of Nuvia cPrime resin. The molar yield of biotin precursor crystals was 75%.

[0110] Example 7

[0111] The method of Example 4 was followed, except that the biotin precursor solution was passed through the resin at a flow rate of 25 BV / h. The molar yield of biotin precursor crystals was 72%.

[0112] It can be seen from the results of the above examples of the present invention that the biotin precursor obtained by the purification method of the present invention has a significantly higher yield.

[0113] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for purifying a biotin precursor, characterized in that: The method includes: (1) passing a biotin precursor solution through a resin containing ionic groups and non-polar groups at a rate of 1-30 BV / h to obtain material A; the resin is selected from at least one of TOYOPEARL MX-Trp-650M resin, UniBPC-SCX resin, Nuvia cPrime resin, and UniBPC-WCX resin; (2) crystallizing material A to obtain biotin precursor crystals; Wherein, the preparation method of the biotin precursor solution comprises: (a) reacting magnesium powder, 1,4-dichlorobutane and a first solvent in the presence of an initiator under anhydrous and oxygen-free conditions to obtain a Grignard reagent; (b) subjecting the thiolactone, the Grignard reagent obtained in step (a), and carbon dioxide to a double addition reaction; (c) hydrolyzing and acidifying the reaction product of step (b), water, and an acid in the presence of a second solvent to obtain a biotin precursor solution; wherein the hydrolysis and acidification reaction in step (c) is carried out at a temperature of 20-50° C. and for 1-6 hours.

2. The method according to claim 1, wherein The biotin precursor solution passes through the resin at a rate of 2-20 BV / h.

3. The method according to claim 1, wherein The particle size of the resin is 20-400 meshes.

4. The method according to claim 3, wherein: The particle size of the resin is 100-250 meshes.

5. The method according to claim 1, wherein The mass fraction of the biotin precursor solution is 10-30%.

6. The method according to claim 1, wherein The crystallization in step (2) is cooling crystallization.

7. The method according to claim 6, wherein: The crystallization comprises: cooling material A to a crystallization temperature and then maintaining the temperature at a constant temperature, wherein the crystallization temperature is -50 to 0° C. and the constant temperature time is 0.5 to 6 hours.

8. The method according to claim 7, wherein: The crystallization comprises: cooling material A to a crystallization temperature and then maintaining the temperature at a constant temperature, wherein the crystallization temperature is -30 to -5°C; and the constant temperature time is 1 to 4 hours.

9. The method according to claim 8, wherein The cooling rate is 0.1-3°C / min.

10. The method according to claim 9, wherein: The cooling rate is 0.2-2°C / min.

11. The method according to claim 8, wherein The crystallization is carried out under stirring conditions, and the stirring speed is 1-150 rpm.

12. The method according to claim 11, wherein The crystallization is carried out under stirring conditions, and the stirring speed is 5-50 rpm.

13. The method according to any one of claims 1 to 12, wherein: The reaction conditions of step (a) include: temperature of 65-75° C.; time of 3-10 h.

14. The method according to claim 13, wherein The reaction conditions of step (a) include: temperature of 65-70° C.; time of 3-8 h.

15. The method according to any one of claims 1 to 12, wherein: The molar ratio of the magnesium powder, 1,4-dichlorobutane, the first solvent and the initiator is 1:0.2-1:10-20:0.001-0.

1.

16. The method according to any one of claims 1 to 12, wherein: The initiator is iodine element or Grignard reagent.

17. The method according to any one of claims 1 to 12, wherein: The first solvent is selected from at least one of tetrahydrofuran, 2-methyltetrahydrofuran and diethyl ether.

18. The method according to any one of claims 1 to 12, wherein: The double addition reaction in step (b) comprises: firstly carrying out a first reaction of the thiolactone with the Grignard reagent obtained in step (a), and then carrying out a second reaction with carbon dioxide.

19. The method according to any one of claims 1 to 12, wherein: The conditions for the hydrolysis and acidification reaction in step (c) include: temperature of 30-50° C.; time of 2-5 hours.

20. The method according to any one of claims 1 to 12, wherein: In step (c), the molar ratio of the reaction product of step (b), water, acid and the second solvent is 1:10-80:10-80:5-40.

21. The method according to any one of claims 1 to 12, wherein: The acid is hydrochloric acid and / or sulfuric acid.

22. The method according to any one of claims 1 to 12, wherein: The second solvent is selected from at least one of toluene, ethyl acetate and chloroform.

23. The method according to any one of claims 1 to 12, wherein: The method further comprises: performing solid-liquid separation on the crystallization product of step (2) to obtain biotin precursor crystals and crystallization mother liquor respectively.

24. The method according to claim 23, wherein The crystallization mother liquor is adsorbed by an activated carbon column.

25. The method according to claim 24, wherein The method further comprises: desorbing the adsorbed activated carbon column.

26. The method according to claim 25, wherein The desorption conditions include: temperature of 60-100° C. and pH of 3-7.

27. The method according to claim 25, wherein The desorption agent for desorption is an organic solvent.

28. The method according to claim 27, wherein The desorption agent is selected from at least one of toluene, ethyl acetate and chloroform.

29. The method according to claim 27, wherein The dosage of the desorption agent is 5-25BV.

30. The method according to any one of claims 1 to 12, wherein: The method further comprises: eluting the resin after adsorption in step (1).

31. The method according to claim 30, wherein The elution temperature is 40-80°C.

32. The method according to claim 30, wherein The eluting agent is selected from at least one of toluene, ethyl acetate and chloroform.

33. The method according to claim 32, wherein The flow rate of the eluting agent is 0.5-10 BV / h.

34. The method of claim 30, wherein: The method further comprises: regenerating the eluted resin.

35. The method according to claim 34, wherein The regeneration agent is n-hexane or petroleum ether.

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