阅读说明：本技术 L-丙氨酸-2-乙基丁酯盐酸盐的纯化方法 (Purification method of L-alanine-2-ethyl butyl ester hydrochloride ) 是由 李德勇 *** 董国润 汪有斌 张丽 于 2020-07-30 设计创作，主要内容包括：一种L-丙氨酸-2-乙基丁酯盐酸盐的纯化方法,属于制药领域。纯化方法包括：将L-丙氨酸-2-乙基丁酯盐酸盐的粗品与溶剂形成的溶解液重结晶,获得L-丙氨酸-2-乙基丁酯盐酸盐成品。其中,溶剂包括乙醇、乙酸乙酯、甲苯、甲基叔丁醚和二氯甲烷中的至少一种。上述实现过程中,通过特定的溶剂的选择结合重结晶的方式,有效提高L-丙氨酸-2-乙基丁酯盐酸盐成品的相对纯度及手性纯度,使得其相对纯度及手性纯度均能够大于99.5％。(A purification method of L-alanine-2-ethyl butyl ester hydrochloride belongs to the field of pharmacy. The purification method comprises the following steps: and recrystallizing the crude product of the L-alanine-2-ethyl butyl ester hydrochloride and a dissolved solution formed by the solvent to obtain a finished product of the L-alanine-2-ethyl butyl ester hydrochloride. Wherein the solvent comprises at least one of ethanol, ethyl acetate, toluene, methyl tertiary butyl ether and dichloromethane. In the implementation process, the relative purity and the chiral purity of the finished product of the L-alanine-2-ethylbutyl ester hydrochloride are effectively improved by combining the selection of a specific solvent with a recrystallization mode, so that the relative purity and the chiral purity can be more than 99.5%.)

1. A method for purifying L-alanine-2-ethylbutyl ester hydrochloride is characterized by comprising the following steps:

recrystallizing a dissolved solution formed by the crude product of the L-alanine-2-ethyl butyl ester hydrochloride and the solvent to obtain a finished product of the L-alanine-2-ethyl butyl ester hydrochloride;

wherein the solvent comprises at least one of ethanol, ethyl acetate, toluene, methyl tertiary butyl ether and dichloromethane.

2. The purification process according to claim 1, wherein the solvent is ethyl acetate.

3. The purification method according to claim 1, wherein when the solvent is ethyl acetate and the recrystallization mode is gradient cooling crystallization, the finished product of the L-alanine-2-ethylbutyl ester hydrochloride comprises single crystals of the L-alanine-2-ethylbutyl ester hydrochloride with a regular shape.

4. The purification method according to claim 1, wherein the recrystallization means includes any one of concentration crystallization under reduced pressure, gradient temperature-reduction crystallization, and slow temperature-reduction crystallization.

5. The purification process according to claim 3 or 4, wherein the gradient temperature-decreasing crystallization comprises: cooling at a gradient of 1.5-3 deg.C every 15-25min and maintaining the temperature for at least 15min every time until the temperature is 25-35 deg.C.

6. The purification process according to claim 3 or 4, wherein the gradient temperature-decreasing crystallization comprises: cooling at 1.5-2.5 deg.C every 20min and maintaining the temperature for 15-25min until the temperature is 25-35 deg.C.

7. The purification method according to claim 1, wherein the temperature of the dissolution solution before recrystallization is 45 to 50 ℃.

8. The purification process according to claim 1, wherein the weight ratio of the crude L-alanine-2-ethylbutyl ester hydrochloride to the solvent is 1: 2-3.

9. The purification method of claim 1, wherein the chiral purity of the crude product is 90.0% to 99.5%, and the relative purity of the crude product is 90.0% to 99.5%.

10. The purification process according to claim 1, further comprising collecting the crystals after recrystallization and vacuum drying to obtain the final product of L-alanine-2-ethylbutyl ester hydrochloride.

Technical Field

The application relates to the field of pharmacy, and particularly relates to a purification method of L-alanine-2-ethylbutyl ester hydrochloride.

Background

RudeSeivir is a small-molecule broad-spectrum antiviral drug developed by Gilidard scientific Inc.

The chiral purity and the relative purity of the L-alanine-2-ethyl butyl ester hydrochloride serving as a Reidesciclovir intermediate have great influence on the curative effect of finally prepared Reidesciclovir, the chiral purity and the relative purity of the existing L-alanine-2-ethyl butyl ester hydrochloride are generally lower than 99.5%, and impurities with similar structures and the same properties, namely chiral isomeric impurities, which are difficult to purify and remove are difficult to effectively remove, can seriously influence the purity of the L-alanine-2-ethyl butyl ester hydrochloride.

Meanwhile, most of the existing L-alanine-2-ethyl butyl ester hydrochloride is mixed crystals, and the structure of the mixed crystals has strong hygroscopicity, so that the mixed crystals are easy to absorb moisture after being stored for a long time, and the falling of ester groups is caused, thereby causing the deterioration of products.

In view of this, the present application is hereby presented.

Disclosure of Invention

The application provides a method for purifying L-alanine-2-ethyl butyl ester hydrochloride, which aims to solve at least one technical problem.

The embodiment of the application is realized as follows:

the application example provides a method for purifying L-alanine-2-ethyl butyl ester hydrochloride, which comprises the following steps:

and recrystallizing the crude product of the L-alanine-2-ethyl butyl ester hydrochloride and a dissolved solution formed by the solvent to obtain a finished product of the L-alanine-2-ethyl butyl ester hydrochloride.

Wherein the solvent comprises at least one of ethanol, ethyl acetate, toluene, methyl tertiary butyl ether and dichloromethane.

In the implementation process, the relative purity and the chiral purity of the finished product of the L-alanine-2-ethylbutyl ester hydrochloride are effectively improved by combining the selection of a specific solvent with a recrystallization mode, so that the relative purity and the chiral purity can be more than 99.5%.

In some possible examples of the present application, the solvent is ethyl acetate.

In some possible examples of the present application, when the solvent is ethyl acetate and the recrystallization is gradient cooling crystallization, the finished product of the L-alanine-2-ethylbutyl ester hydrochloride comprises single crystals of the L-alanine-2-ethylbutyl ester hydrochloride with a regular shape.

In the implementation process, the specific solvent ethyl acetate is selected and combined with a specific recrystallization mode, so that the relative purity and the chiral purity of the finished product of the L-alanine-2-ethyl butyl ester hydrochloride are remarkably improved and can reach 99.9%, meanwhile, the single crystal L-alanine-2-ethyl butyl ester hydrochloride can be obtained, and the single crystal L-alanine-2-ethyl butyl ester hydrochloride has large particle size, reduces the surface area of the material, can be stored for a longer time, is more stable in structure and is less prone to moisture absorption and deterioration compared with a mixed crystal structure.

In some possible examples of the present application, the recrystallization means includes any one of concentration crystallization under reduced pressure, gradient temperature-decreasing crystallization, and slow temperature-decreasing crystallization.

In some possible examples of the present application, the gradient temperature-decreasing crystallization comprises: cooling at a gradient of 1.5-3 deg.C every 15-25min and maintaining the temperature for at least 15min every time until the temperature is 25-35 deg.C.

Optionally, cooling at 1.5-2.5 deg.C every 20min, and maintaining the temperature for 15-25min after each cooling, until the temperature is 25-35 deg.C.

Optionally, the gradient temperature-decreasing crystallization comprises: cooling at 2 deg.C every 20min and maintaining the temperature for 15-25min until the temperature is 25-35 deg.C.

In the implementation process, through the matching of the parameters of the gradient cooling crystallization and the reasonable matching of the parameters and the solvent, the crude product is effectively purified, and the relative purity and the chiral purity of the finished product of the L-alanine-2-ethylbutyl ester hydrochloride are improved.

In one possible example of the application, the temperature of the dissolution solution before recrystallization is 45-50 ℃.

At the above temperature, the crude product has good solubility in ethyl acetate.

In one possible example of the present application, the weight ratio of crude L-alanine-2-ethylbutyl ester hydrochloride to solvent is 1: 2-3.

The above proportion ensures good solubility of the crude product in the solvent.

In one possible example of the present application, the chiral purity of the crude product is 90.0% to 99.5%, and the relative purity of the crude product is 90.0% to 99.5%.

Under the set conditions, the impurity interference is small, and the crude product is effectively purified, so that the relative purity and the chiral purity of the crude product are improved to be more than 99.5 percent.

In one possible example of the present application, after recrystallization, the purification method further comprises collecting the crystals and vacuum drying to obtain the finished product of L-alanine-2-ethylbutyl ester hydrochloride.

The purification method of L-alanine-2-ethyl butyl ester hydrochloride provided by the application has the beneficial effects that:

the purification purity of the L-alanine-2-ethyl butyl ester hydrochloric acid finished product is greatly improved through the synergistic effect of the specific solvent and the purification mode of recrystallization, and the solvent can be recycled, so that the method is suitable for industrial production, and has the advantages of no toxicity, no harm, environmental protection, safety and low production cost.

Through tests, by the purification method, when the solvent is ethyl acetate and a gradient cooling crystallization mode is adopted, the L-alanine-2-ethylbutyl ester hydrochloride with a single crystal structure can be obtained, the relative purity is higher than 99.5%, the chiral purity is higher than 99.5%, the product performance is very excellent, and the method has unexpected beneficial effects.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

FIG. 1 is a relative purity profile of crude L-alanine-2-ethylbutyl ester hydrochloride;

FIG. 2 is a chiral purity profile of a crude L-alanine-2-ethylbutyl ester hydrochloride;

FIG. 3 is an electron microscope scan of the L-alanine-2-ethylbutyl ester hydrochloride product of example 1;

FIG. 4 is a graph of the relative purity of the L-alanine-2-ethylbutyl ester hydrochloride product of example 1;

FIG. 5 is a chiral purity map of the L-alanine-2-ethylbutyl ester hydrochloride product of example 1;

FIG. 6 is an electron microscope scan of the product L-alanine-2-ethylbutyl ester hydrochloride of example 5.

Detailed Description

Embodiments of the present application will be described in detail below with reference to examples, but those skilled in the art will appreciate that the following examples are only illustrative of the present application and should not be construed as limiting the scope of the present application. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The applicant finds that when the solvent is at least one of ethanol, ethyl acetate, toluene, methyl tertiary butyl ether and dichloromethane, the relative purity and chiral purity of the finished L-alanine-2-ethyl butyl ester hydrochloride can be obviously improved by adopting a recrystallization mode, and particularly, when the solvent is ethyl acetate and the gradient decompression condition is adopted, the finished single-crystal L-alanine-2-ethyl butyl ester hydrochloride can be obtained.

The following is a detailed description of the purification method of L-alanine-2-ethylbutyl ester hydrochloride according to the examples of the present application:

a method for purifying L-alanine-2-ethylbutyl ester hydrochloride, comprising:

s1, obtaining a dissolving solution formed by a crude product of L-alanine-2-ethyl butyl ester hydrochloride and a solvent.

Wherein the solvent comprises at least one of ethanol, ethyl acetate, toluene, methyl tertiary butyl ether and dichloromethane. Specifically, the solvent may be ethanol, ethyl acetate, toluene, methyl tertiary butyl ether or dichloromethane, or may be a mixture of ethanol and ethyl acetate, or a mixture of ethanol and methyl tertiary butyl ether, which is not limited herein.

Wherein the temperature of the dissolving solution is 45-50 deg.C, such as 45 deg.C, 47 deg.C, 48 deg.C, 49 deg.C or 50 deg.C.

The method for obtaining the dissolved solution formed by the crude product of the L-alanine-2-ethyl butyl ester hydrochloride and the solvent comprises the following steps: mixing the crude product of L-alanine-2-ethyl butyl ester hydrochloride with ethyl acetate, stirring and heating to obtain a solution at 45-50 ℃.

In addition to the above manner, the crude L-alanine-2-ethylbutyl ester hydrochloride can be dissolved in a solvent at 45-50 ℃ to obtain the above solution at 45-50 ℃.

Alternatively, the weight ratio of the crude L-alanine-2-ethylbutyl ester hydrochloride to the solvent is 1: 2-3. For example, the weight ratio of the crude L-alanine-2-ethylbutyl ester hydrochloride to the solvent is 1:2, 1:2.2, 1:2.5, 1:2.7 or 1: 3.

It should be noted that the chiral purity and the relative purity of the crude product of L-alanine-2-ethylbutyl ester hydrochloride are equal to or less than 99.5%, for example, 80% to 99.5%, optionally, the crude product of L-alanine-2-ethylbutyl ester hydrochloride is a mixed crystal, and the chiral purity of the crude product is 90.0% to 99.5%, optionally, the relative purity of the crude product is 90.0% to 99.5%, under the above purity conditions, the purification by the method of the present application is facilitated, and the relative purity and the chiral purity of the purified L-alanine-2-ethylbutyl ester hydrochloride finished product are high.

S2, recrystallizing the 45-50 ℃ dissolved solution.

Wherein, the recrystallization mode comprises any one of decompression concentration crystallization, gradient cooling crystallization and slow cooling crystallization.

For example, the slow cooling crystallization includes: slowly cooling to 25-30 ℃ within 2-3 h.

Optionally, the gradient temperature-decreasing crystallization comprises: cooling at a gradient of 1.5-3 deg.C every 15-25min and maintaining the temperature for at least 15min every time until the temperature is 25-35 deg.C. For example, the temperature is reduced by 1.5 ℃, 1.7 ℃, 1.9 ℃, 2 ℃, 2.1 ℃, 2.4 ℃, 2.6 ℃ or 3 ℃ every 15min, 17min, 18min, 20min, 22min, 24min or 25min, and the temperature is preserved for at least 15min after each temperature reduction until the temperature is reduced to 25 ℃, 26 ℃, 27 ℃, 28 ℃, 30 ℃, 33 ℃ or 35 ℃.

Further, the gradient cooling crystallization comprises: cooling at 1.5-2.5 deg.C every 20min and maintaining the temperature for 15-25min until the temperature is 25-35 deg.C.

Further, the gradient cooling crystallization comprises: cooling at 2 deg.C every 20min and maintaining the temperature for 15-25min until the temperature is 25-35 deg.C.

Optionally, when the solvent is ethyl acetate and the recrystallization mode is the gradient temperature-reduction crystallization, the finished product of the L-alanine-2-ethyl butyl ester hydrochloride comprises single crystals of the L-alanine-2-ethyl butyl ester hydrochloride with a regular shape; that is, the single-crystal L-alanine-2-ethylbutyl ester hydrochloride in which the crystal particle size of the single-crystal L-alanine-2-ethylbutyl ester salt was > 800. mu.m was obtained in the above manner.

It should be noted that the selection of the solvent and the specific mode of recrystallization have significant influence on the crystalline phase, chiral purity and relative purity of the finished product of L-alanine-2-ethylbutyl ester hydrochloride, in the embodiment of the present application, in addition to the fact that the solvent is ethyl acetate-gradient cooling crystallization mode, the finished product of single-crystal L-alanine-2-ethylbutyl ester hydrochloride can be obtained, the rest of solvents and/or different recrystallization modes are combined, the obtained finished product of L-alanine-2-ethylbutyl ester hydrochloride is mixed crystal, and the crystal particle size of the mixed crystal L-alanine-2-ethylbutyl ester hydrochloride is lower than 50 μm.

S3, collecting the solid, and drying in vacuum to obtain the finished product of the L-alanine-2-ethyl butyl ester hydrochloride.

Optionally, the temperature of vacuum drying is 30-50 ℃.

The purification process of L-alanine-2-ethylbutyl ester hydrochloride according to the present application is further described in detail with reference to examples.

In the following examples, the relative purity and chiral purity of the crude and finished product of L-alanine-2-ethylbutyl ester hydrochloride were determined by HPLC, wherein: indicates the relative purity of the compound; EE value indicates the chiral purity of the compound. The L value represents the particle size of the crystals of L-alanine-2-ethylbutyl ester hydrochloride.

Detecting the relative purity of the product by high performance liquid chromatography: agilent 1200 liquid chromatograph, column: agilent SB-C18 (4.6X 150mm, 5 μm), detection wavelength 265nm, column temperature 25 ℃, flow rate 1.0ml/min, mobile phase: 0.1% aqueous phosphoric acid solution-acetonitrile (70: 30 by volume), and a sample amount of 5. mu.l was introduced.

Detecting the chiral purity of the product by high performance liquid chromatography: the detection conditions are as follows: shimadzu LC-20A/UV; a chromatographic column: CHIRALCEL OD-H (4.6 mm. times.250 mm, 5 μm), mobile phase: n-hexane-ethanol-diethylamine (volume ratio 40:60:0.2), flow rate: 1mL/min, column temperature: 25 ℃, detection wavelength: 210nm, and the sample size is 5 μ l.

In the following examples, the same crude L-alanine-2-ethylbutyl ester hydrochloride is used, wherein FIG. 1 and FIG. 2 show the relative purity and chiral purity of the crude L-alanine-2-ethylbutyl ester hydrochloride, respectively, wherein Table 1 shows the detection results corresponding to FIG. 1, Table 2 shows the detection results corresponding to FIG. 2, wherein Peak No. 5 in Table 1 shows L-alanine-2-ethylbutyl ester hydrochloride, and Peak No. 2 in Table 2 shows L-alanine-2-ethylbutyl ester hydrochloride.

TABLE 1 results of relative purity measurements

TABLE 2 relative purity test results

That is, HPLC: 99.262%, EE: 92.78 percent.