Calcitriol impurity B and preparation method thereof
The method for preparing calcitriol impurity B solves the problem of the lack of synthesis methods in the existing technology, and achieves high yield and high purity of calcitriol impurity B product, ensuring the consistency and safety of drug quality.
Patent Information
- Application Number
- CN202511064744.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-31
- Publication Date
- 2025-11-21
AI Technical Summary
The lack of a synthetic method for calcitriol impurity B in the existing technology makes it difficult to effectively control in quality control, affecting the safety and consistency of the drug.
Calcitriol impurity B was prepared by mixing intermediate 3 with a base and a solvent, heating under reflux, and then adding a photosensitizer under light conditions. The specific steps included using sodium hydroxide, potassium hydroxide, or lithium hydroxide as the base, water, methanol, or tetrahydrofuran as the solvent, 9-acetylanthracene as the photosensitizer, light wavelength of 365-370 nm, dichloromethane, ethyl acetate, or tetrahydrofuran as the solvent, selenium dioxide as the catalyst, and separation and purification steps including column chromatography or recrystallization.
A high yield and high purity preparation of calcitriol impurity B was achieved, with product purity reaching over 99%, meeting quality control requirements.
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Figure CN120987822A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of pharmaceutical technology, specifically to a calcitriol impurity B and its preparation method. Background Technology
[0002] Calcitriol, chemically named 9,10-open-cholesterol-5Z,7E,10(19)-triene-1α,3β,25-triol, has the following chemical structure:
[0003]
[0004] Chemical structure of calcitriol
[0005] Calcitriol plays a crucial role in regulating calcium and phosphorus metabolism and bone mineralization, and also acts as a key regulator in physiological activities such as induction of cell differentiation and inhibition of cell proliferation. Currently, calcitriol is used to treat postmenopausal women and senile osteoporosis, hypoparathyroidism, renal osteodystrophy, vitamin D3-dependent rickets, and renal rickets, renal bone changes, and hypoparathyroidism caused by various kidney diseases.
[0006] Drug impurities are a crucial aspect of drug research and production control. In some drugs, the presence of impurities is often closely related to adverse reactions, impacting drug safety and quality controllability. Therefore, impurity research is a vital step in ensuring clinical drug safety and quality controllability, and is also a key indicator for evaluating drug consistency.
[0007] In the EP and USP pharmacopoeia standards, calcitriol impurity B is an important impurity in its quality research and control. The chemical name of impurity B is (5Z,7E)-9,10-open-cholest-5,7,10(19)-triene-1β,3β,25-triol, and its chemical structure is shown below:
[0008]
[0009] Structural formula of calcitriol impurity B
[0010] A comparison of the structural formulas of calcitriol and calcitriol impurity B reveals that they are diastereomers based on a chiral carbon atom at position 1. In calcitriol, the hydroxyl group at position 1 is located at the α-position, while in calcitriol impurity B, the hydroxyl group at position 1 is located at the β-position. Calcitriol impurity B is generated during the hydroxylation reaction at position 1 of the carbon atom during calcitriol synthesis. Due to the non-specific stereoselectivity of this reaction, the generation of this impurity cannot be completely avoided and must be separated in subsequent processes. Therefore, calcitriol impurity B is considered an important control impurity in quality studies.
[0011] There are currently no reported methods for synthesizing calcitriol impurity B. Therefore, it is necessary to develop a method for preparing a calcitriol impurity B reference standard so as to play an important role in the quality control of calcitriol. Summary of the Invention
[0012] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a calcitriol impurity B and its preparation method, thereby solving the technical problem of how to prepare a calcitriol impurity B reference standard in the prior art.
[0013] To achieve the above-mentioned technical objectives, the present invention provides a method for preparing calcitriol impurity B, comprising the following steps:
[0014] S1. Intermediate 3, the first solvent and the base are mixed and then heated under reflux to obtain intermediate 4; the ratio of intermediate 3, the first solvent and the base is (12-16)g:(170-180)mL:(10-20)g.
[0015] S2. Dissolve intermediate 4 in a second solvent, cool to 0-5°C, then add a photosensitizer and react under light irradiation to obtain the calcitriol impurity B.
[0016] The structural formula of intermediate 3 is as follows:
[0017]
[0018] The structural formula of intermediate 4 is as follows:
[0019]
[0020] In any embodiment, in step S1, the alkali is sodium hydroxide, potassium hydroxide, or lithium hydroxide.
[0021] In any embodiment, in step S1, the first solvent is a mixture of water and methanol, ethanol, or tetrahydrofuran. For example, it can be a mixture of water and methanol, a mixture of water and ethanol, or a mixture of water and tetrahydrofuran.
[0022] In any embodiment, in step S2, the photosensitizer is 9-acetylanthracene.
[0023] In any embodiment, in step S2, the illumination wavelength of the photoreaction is 365-370 nm.
[0024] In any embodiment, in step S2, the second solvent is one or more of dichloromethane, trichloromethane, ethyl acetate, and tetrahydrofuran.
[0025] In any embodiment, in step S1, the intermediate 3 is prepared by the following steps:
[0026] Compound I, catalyst, co-oxidant and third solvent are subjected to hydroxylation reaction to obtain mixture A;
[0027] Mixture A, the fourth solvent, and phenylboronic acid are reacted to obtain mixture B, and mixture B is separated and purified to obtain intermediate 3;
[0028] The structural formula of compound I is as follows:
[0029]
[0030] In any embodiment, the co-oxidant is N-methylmorpholine-N-oxide; and / or, the third solvent is one or more of halogenated hydrocarbons and small molecule alcohols, preferably a mixed solvent of dichloromethane and methanol; and / or, the fourth solvent is an aprotic solvent, including one or more of dichloromethane, trichloromethane, ethyl acetate and tetrahydrofuran.
[0031] In any embodiment, the catalyst is selenium dioxide; and / or, the separation and purification method is column chromatography or recrystallization.
[0032] In addition, this specific embodiment also proposes a calcitriol impurity B, which is prepared by the above-described method.
[0033] Compared with the prior art, the beneficial effects of the present invention include: the preparation method of calcitriol impurity B proposed in the present invention includes the following steps: S1, mixing intermediate 3, a first solvent and an alkali, and then heating to reflux to obtain intermediate 4; S2, dissolving intermediate 4 in a second solvent, cooling to 0-5°C, and then adding a photosensitizer to react under light conditions to obtain the calcitriol impurity B. The yield of the obtained calcitriol impurity B is high, and the purity of the product can reach more than 99%. Attached Figure Description
[0034] Figure 1 This is the HPLC chromatogram of calcitriol impurity B obtained in Example 1 of this invention.
[0035] Figure 2 This is the HPLC chromatogram of calcitriol impurity B obtained in Example 2 of the present invention. Detailed Implementation
[0036] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60–120 and 80–110 are listed for a specific parameter, it is understood that ranges of 60–110 and 80–120 are also expected. Furthermore, if minimum range values of 1 and 2 are listed, and if maximum range values of 3, 4, and 5 are listed, then the following ranges are all expected: 1–3, 1–4, 1–5, 2–3, 2–4, and 2–5. In this application, unless otherwise stated, the numerical range "a–b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.
[0037] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.
[0038] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).
[0039] This specific embodiment provides a method for preparing calcitriol impurity B, including the following steps:
[0040] S1. Mix intermediate 3, the first solvent and the base, and then heat to react to obtain intermediate 4;
[0041] S2. Dissolve intermediate 4 in a second solvent, cool to 0-5°C, then add a photosensitizer and react under light conditions to obtain the calcitriol impurity B; the photosensitizer is 9-acetylanthracene; the light wavelength of the light reaction is 365-370nm; the second solvent is one or more of dichloromethane, trichloromethane, ethyl acetate and tetrahydrofuran.
[0042] The structural formula of intermediate 3 is as follows:
[0043]
[0044] The structural formula of intermediate 4 is as follows:
[0045]
[0046] In some embodiments, in step S1, the alkali is sodium hydroxide, potassium hydroxide, or lithium hydroxide; the first solvent is a mixture of water and methanol, ethanol, or tetrahydrofuran.
[0047] In some embodiments, in step S1, the intermediate 3 is obtained by the following steps:
[0048] Compound I, a catalyst, a co-oxidizing agent, and a third solvent are subjected to a hydroxylation reaction to generate mixture A; the co-oxidizing agent is N-methylmorpholine-N-oxide; the third solvent is one or more of halogenated hydrocarbons and small molecule alcohols, preferably a mixed solvent of dichloromethane and methanol; the catalyst is selenium dioxide;
[0049] Mixture A, the fourth solvent, and phenylboronic acid are reacted to generate mixture B. Mixture B is then separated and purified to obtain intermediate 3. The fourth solvent is an aprotic solvent, including one or more of dichloromethane, trichloromethane, ethyl acetate, and tetrahydrofuran. The separation and purification are performed by column chromatography or recrystallization.
[0050] The structural formula of compound I is as follows:
[0051]
[0052] The relevant reaction formulas are as follows:
[0053]
[0054] This specific embodiment also proposes a calcitriol impurity B, which is prepared by the above-described method.
[0055] The method for preparing calcitriol impurity B proposed in this specific embodiment has the following inventive concept:
[0056] In the presence of a co-oxidant, under the catalysis of selenium dioxide, the compound of formula I is hydroxylated in a suitable solvent to generate mixture 1;
[0057] Mixture 1 is reacted with phenylboronic acid in a suitable solvent to produce mixture 2;
[0058] Mixture 2 was separated and purified to produce intermediate 3;
[0059] Intermediate 3 is hydrolyzed to generate intermediate 4;
[0060] Intermediate 4 was reacted under light to generate calcitriol impurity B.
[0061] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0062] In this invention, the terms "some embodiments," "this embodiment," and examples are used to describe a subset of all possible embodiments. However, it is understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with each other without conflict.
[0063] If the application documents contain similar descriptions such as "first / second", the following explanation shall be added: In the following description, the terms "first / second / third" are used only to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first / second / third" may be interchanged in a specific order or sequence where permitted, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.
[0064] In this embodiment, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, object A and / or object B can represent three situations: object A exists alone, object A and object B exist simultaneously, and object B exists alone.
[0065] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.
[0066] Example 1
[0067] 50 g (125 mmol) of compound I was added to a mixed solution of 250 ml dichloromethane and 250 ml methanol and stirred. 1.39 g (12.5 mmol) of selenium dioxide, 29.25 g (250 mmol) of N-methylmorpholine-N-oxide and 17 g (250 mmol) of imidazole were added to the reaction system. The mixture was heated to reflux at 42 °C for 5 hours, cooled to room temperature, concentrated, and ethyl acetate and water were added. The organic phase was separated, washed with water, washed with saturated sodium chloride solution, dried over anhydrous sodium sulfate, concentrated to dryness, and column chromatography was used to obtain 30.7 g of a yellow oily substance, which is mixture 1.
[0068] The reaction formula is as follows:
[0069]
[0070] 30.0g of mixture 1 was added to 200ml of tetrahydrofuran, stirred, and 8.8g of phenylboronic acid was added. The mixture was reacted at room temperature (25℃) for 24 hours. The reaction solution was concentrated to dryness to obtain 36.5g of mixture 2.
[0071] The reaction formula is as follows:
[0072]
[0073] Mixture 2 was subjected to silica gel column chromatography with ethyl acetate / n-hexane (1 / 3) as the eluent, yielding intermediate 3 in an amount of 12.6 g;
[0074] The reaction formula is as follows:
[0075]
[0076] 12.6 g of intermediate 3 was dissolved in 150 ml of tetrahydrofuran, and 20 ml of water and 10 g of sodium hydroxide were added. The mixture was stirred and heated to reflux for 3 hours. The reaction solution was concentrated under reduced pressure. 300 ml of ethyl acetate and 100 ml of deionized water were added to the residue, and the mixture was stirred for 30 minutes. After standing, the organic phase was separated, washed with water and saturated sodium chloride solution, dried, and concentrated to give 8.67 g of intermediate 4. Yield: 83.0%; HPLC purity: 98.6%.
[0077] The reaction formula is as follows:
[0078]
[0079] Intermediate 4 (8.6 g) was dissolved in 200 ml of dry tetrahydrofuran, magnetically stirred, and cooled to 0 °C. 455 mg of 9-acetylanthracene was added, and the mixture was reacted under 365 nm light for 15 minutes. The mixture was concentrated under reduced pressure, and the residue was precipitated by silica gel column chromatography with ethyl acetate / n-hexane (1 / 1) as elution, yielding 8.3 g of a white, foamy solid. 415 ml of methyl formate was added, and the mixture was heated to reflux until completely dissolved. Crystallization was carried out at 2–8 °C for 24 hours. The crystals were filtered and dried under vacuum at room temperature to constant weight, yielding 4.1 g of a white solid, which was calcitriol impurity B. Yield: 47.7%. Figure 1 HPLC purity: 99.37%.
[0080] The reaction formula is as follows:
[0081]
[0082] Example 2
[0083] Mix 15.5 g of intermediate 3 with 150 ml of ethanol, stir, add 20 ml of water and 18.5 g of potassium hydroxide. Heat to reflux and react for 3.5 hours. Concentrate the reaction solution under reduced pressure. Add 350 ml of ethyl acetate and 150 ml of water to the residue, stir for 10 minutes, let stand, separate the organic phase, wash the organic phase with water, wash with saturated sodium chloride solution, dry with anhydrous sodium sulfate, concentrate, and give 10.2 g of intermediate 4. Yield: 79.0%; HPLC purity: 98.3%.
[0084] The reaction formula is as follows:
[0085]
[0086] Intermediate 4 (10.0%) was dissolved in 300 ml of ethyl acetate, magnetically stirred, and cooled to 0 °C. 500 mg of 9-acetylanthracene was added, and the mixture was reacted under 365 nm light for 25 minutes. The solution was concentrated under reduced pressure to obtain a yellow oil. This oil was eluted with ethyl acetate / n-hexane (1 / 1) using silica gel column chromatography. The target product was collected and concentrated under reduced pressure to obtain 9.5 g of a white, foamy solid. 475 ml of methyl formate was added, and the mixture was heated to reflux to obtain a clear, foamy solution. The solution was naturally cooled to room temperature and then allowed to stand at 2–8 °C for 24 hours. It was then filtered, washed with cold methyl formate, and dried under vacuum at room temperature to constant weight to obtain 5.2 g of a white solid, which was calcitriol impurity B. Yield: 52.0%. Figure 2 HPLC purity: 99.48%.
[0087] The reaction formula is as follows:
[0088]
[0089] Other beneficial effects of this invention include:
[0090] Previously, there were no reports on methods for preparing calcitriol impurity B. This invention discloses a method for synthesizing calcitriol impurity B, which can be used to synthesize a calcitriol impurity B reference standard, and is of great significance for the quality control of calcitriol.
[0091] The method for synthesizing calcitriol impurity B disclosed in this invention has a high yield, is simple to operate, and the purity of the product can reach over 99%.
[0092] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. A method for preparing calcitriol impurity B, characterized in that, Includes the following steps: S1. Mix intermediate 3, the first solvent and the base, and then heat to reflux to obtain intermediate 4; S2. Dissolve intermediate 4 in a second solvent, cool to 0-5°C, then add a photosensitizer and react under light irradiation to obtain the calcitriol impurity B. The structural formula of intermediate 3 is as follows: The structural formula of intermediate 4 is as follows:
2. The method for preparing calcitriol impurity B according to claim 1, characterized in that, In step S1, the alkali is sodium hydroxide, potassium hydroxide, or lithium hydroxide.
3. The method for preparing calcitriol impurity B according to claim 1, characterized in that, In step S1, the first solvent is a mixture of water and methanol, ethanol or tetrahydrofuran.
4. The method for preparing calcitriol impurity B according to claim 1, characterized in that, In step S2, the photosensitizer is 9-acetylanthracene.
5. The method for preparing calcitriol impurity B according to claim 1, characterized in that, In step S2, the illumination wavelength of the photoreaction is 365-370 nm.
6. The method for preparing calcitriol impurity B according to claim 1, characterized in that, In step S2, the second solvent is one or more of dichloromethane, trichloromethane, ethyl acetate, and tetrahydrofuran.
7. The method for preparing calcitriol impurity B according to claim 1, characterized in that, In step S1, the intermediate 3 is prepared by the following steps: Compound I, catalyst, co-oxidant and third solvent are subjected to hydroxylation reaction to obtain mixture A; Mixture A, the fourth solvent, and phenylboronic acid are reacted to obtain mixture B, and mixture B is separated and purified to obtain intermediate 3; The structural formula of compound I is as follows:
8. The method for preparing calcitriol impurity B according to claim 7, characterized in that, The co-oxidant is N-methylmorpholine-N-oxide; and / or, the third solvent is one or more of halogenated hydrocarbons and small molecule alcohols, preferably a mixed solvent of dichloromethane and methanol; and / or, the fourth solvent is an aprotic solvent, including one or more of dichloromethane, trichloromethane, ethyl acetate and tetrahydrofuran.
9. The method for preparing calcitriol impurity B according to claim 7, characterized in that, The catalyst is selenium dioxide; and / or the separation and purification method is column chromatography or recrystallization.
10. A calcitriol impurity B, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.