阅读说明：本技术 一种前阿尔法骨化醇的制备方法 (Preparation method of pre-alpha-calciferol ) 是由 邱妍川 张慧梅 钟玲 于 2019-05-17 设计创作，主要内容包括：发明提供了一种前阿尔法骨化醇的制备方法。采用高温水浴回流制备前阿尔法骨化醇,以高效液相色谱法对其进行分离纯化,并运用HRMS,NMR对其进行了结构鉴定,结果显示所得化合物为前阿尔法骨化醇。该方法过程简单、周期短、成本低且收率高,可循环制备。(The invention provides a preparation method of pre-alpha calciferol. The method comprises the steps of preparing the pre-alpha calciferol by adopting high-temperature water bath reflux, separating and purifying the pre-alpha calciferol by using a high performance liquid chromatography, carrying out structure identification on the pre-alpha calciferol by using HRMS and NMR, and displaying the result that the obtained compound is the pre-alpha calciferol. The method has the advantages of simple process, short period, low cost, high yield and cyclic preparation.)

1. A preparation method of pre-alpha-calciferol is characterized by comprising the following steps:

1, placing alfacalcidol raw material into a reactor, and dissolving with absolute ethyl alcohol;

heating the reactor in the step 1, and condensing and refluxing;

taking out the product in the reactor in the step 2, and removing ethanol by rotary evaporation;

4) adding mobile phase to dissolve the product obtained in the step 3, namely, carrying out liquid phase preparation

Collecting the components for 17-20 min by a silica gel column chromatography;

concentrating the fraction obtained in step 5) to gel form;

freeze-drying the gelatinous product obtained in step 6 to obtain a white powder of the pro-alfacalcidol.

2. Process for the preparation of pre-alpha-calciferol according to claim 1, characterized in that: the reactor in the step 1) is a round-bottom flask; the weight volume ratio of the alfacalcidol raw material to the absolute ethyl alcohol is as follows: 2: 1-4: 1; the unit of weight is mg and the unit of volume is mL, which can be scaled up.

3. Process for the preparation of pre-alpha-calciferol according to claim 1 or 2, characterized in that: step 2) the heating mode is heating by a hot water bath at the temperature of 80-90 ℃; the condensing reflux time is 1.5 hours to 2 hours.

4. Process for the preparation of pre-alpha-calciferol according to claim 1 or 3, characterized in that: and 3, removing the ethanol by rotary steaming at 55-65 ℃ under reduced pressure in a hot water bath.

5. Process for the preparation of pre-alpha-calciferol according to claim 1, characterized in that: step 4. the mobile phase comprises the components of n-heptane, ethyl acetate and dichloromethane;

6. process for the preparation of pre-alpha-calciferol according to claim 1 or 4, characterized in that: the weight volume ratio of the product obtained in the step 3) to the mobile phase is as follows: 5: 1-10: 1; the unit of weight is mg and the unit of volume is mL, which can be scaled up.

7. Process for the preparation of pre-alpha-calciferol according to claim 1 or 4, characterized in that: the chromatographic column in the step 5) is SILICA gel column (GRACE, ALLTIMA, SILICA, 4.6X 250mm, 5 μm-10 μm). The column temperature is 27 ℃ to 33 ℃.

8. Process for the preparation of pre-alpha-calciferol according to claim 1 or 4, characterized in that: and 6, concentrating the product into gel by nitrogen blowing under ice bath condition.

9. Process for the preparation of pre-alpha-calciferol according to claim 1 or 4, characterized in that: in step 7, the freeze-drying process is vacuum freeze-drying.

Technical Field

The present invention relates to drug analysis experiments.

Background

The chemical name of alpha-calciferol is (5Z, 7E) -9, 10-secocholest-5, 7, 10(19) -triene-1 α, 3 β -diol, the action mechanism is that the utilization of calcium is regulated, osteomalacia is avoided, the active metabolite also has the regulation effect on osteoblast, important bone matrix protein and growth factor are produced, and the alpha-calciferol tablet is sold in Japan in 7 months of 1988, and the alpha-calciferol tablet is applicable to osteoporosis, chronic renal failure improvement, parathyroid hypofunction, vitamin D resistant rickets, osteomalacia and other diseases and has various symptoms of abnormal vitamin D metabolism.

In the consistency evaluation pharmaceutical research of the home-made alfacalcidol tablets and the reference preparation according to the related guiding principles and file requirements, the fact that a certain level of pro-alfacalcidol exists in both the originally-researched product and the home-made product is found, and the quality standards of alfacalcidol raw materials and tablets in pharmacopoeia are not controlled. In EP9.2 alfacalcidol feedstock quality standards, there is a description of "tautomerism of alfacalcidol to pro-alfacalcidol occurs in solution, both compounds being active substances depending on temperature and time" (see figure 1). Under the term of content measurement, "the peak of the pre-alfacalcidol is counted as the content, if necessary". Since prealgacalciferol is both an active substance, it is necessary to control the contents of alfacalcidol and prealgalcidol simultaneously under the planned content measurement. However, due to the difference of the response of the ultraviolet light of the alfacalcidol and the alfacalcidol, errors also exist in the content determination process. The high performance liquid chromatography with the former alfacalcidol as the reference substance can directly position the chromatographic peak position, obviously reduce or eliminate the influence caused by relative retention time and ultraviolet response difference, and has more accurate content determination, but the method needs the high-purity former alfacalcidol as the reference substance.

Because the pre-alfacalcidol is extremely unstable and is easy to be subjected to tautomerism with the alfacalcidol at normal temperature, if the pre-alfacalcidol is directly synthesized, a synthesis route needs to be designed, and the development cycle is long, the cost is high, and the difficulty is high. If the pre-alpha-calcitol is directly separated and prepared from the bulk drugs, a large amount of bulk drugs are consumed, and the problem of high material cost also exists.

Disclosure of Invention

The invention aims to provide a method for preparing pre-alpha-calciferol, which is characterized by comprising the following steps of:

1, placing alfacalcidol raw material into a reactor, and dissolving with absolute ethyl alcohol;

heating the reactor in the step 1, and condensing and refluxing;

taking out the product in the reactor in the step 2, and removing ethanol by rotary evaporation;

4) adding mobile phase to dissolve the product obtained in the step 3, namely, carrying out liquid phase preparation

Collecting 17-20 min components by silica gel column chromatography at a flow rate of 4.5-5.5 mL/min;

concentrating the fraction obtained in step 5) to gel form;

freeze-drying the gelatinous product obtained in step 6 to obtain a white powder of the pro-alfacalcidol.

The technical effect of the invention is undoubtedly that the pre-alpha-calciferol is obtained by adopting a directional degradation mode and is separated and purified by chromatographic preparation and other means. The preparation method comprises four steps of high-temperature preparation, separation and purification, low-temperature concentration and reduced pressure drying, and has the advantages of simple preparation process, short period, low cost and high yield. Through detection, the pre-alpha-calciferol with the purity of more than 95 percent can be obtained in a short time, and the requirement of using the pre-alpha-calciferol as a reference substance is met. And the alpha-calciferol which is not damaged under the high-temperature preparation condition can be collected and then circularly prepared, so that the utilization rate is greatly improved, and the cost is reduced.

Drawings

FIG. 1 tautomerism of alfacalcidol to Prefalcidol

FIG. 2 HPLC detection of crude Pre-alpha-calciferol solution

FIG. 3 HPLC detection of crude Pre-Alkalcalcitol solution

FIG. 4 front alpha-calciferol chemical structure diagram.

Detailed Description

The present invention is further illustrated by the following examples, but it should not be construed that the scope of the above-described subject matter is limited to the following examples. Various substitutions and alterations can be made without departing from the technical idea of the invention and the scope of the invention is covered by the present invention according to the common technical knowledge and the conventional means in the field.