TWI481612B - Preparation process of (6r)-tetrahydrobiopterin hydrochloride - Google Patents

Description

Method for preparing (6 R )-tetrahydrobiopterin hydrochloride

This invention relates to a process for the preparation of a (6R)-tetrahydrobiopterin hydrochloride.

(6R)-Tetrahydrobiopterin (BH4) is a coenzyme produced by the organism itself and belongs to the natural ape family. The lanthanide is present in the organism in oxidized and reduced form, but only the reduced (6R)-5,6,7,8-tetrahydrobiopterin is biologically active, which is a coenzyme of phenylalanine hydroxylase. . Lack of BH4 will not only cause hyperphenylalaninemia, but also affect the formation of a variety of neurotransmitters, causing patients with a series of nervous system symptoms different from phenylketonuria.

Preparation of (6 R )-tetrahydrobiopterin, usually by first hydrogenating L -biopterin (abbreviated as BH2) to obtain a mixture of two diastereomers of R and S , and then by multiple times Obtained by recrystallization. US 2006/0142573 provides an industrialized method for the large scale preparation of L -biopterin. US 4,713,454 discloses a condition in which the reaction substrate is basic in the presence of a platinum-based metal catalyst and using an organic base (eg, an amine, including a primary amine, a secondary amine, a tertiary amine, and a quaternary amine) The method of preparing a (6 R )-tetrahydrobiopterin by performing a high pressure hydrogenation reaction of L -biopterin. In this case, special emphasis was placed on the use of inorganic bases to control the pH, which would reduce the product's asymmetric ratio R/S value.

In the present art, there remains a need for existing (6 R) - Preparation of tetrahydrobiopterin make improvements, in particular to improve the ease of operation, to reduce production costs, suitable for industrial production.

The present invention proposes for the first time to adjust the pH value of the reaction substrate by using potassium hydroxide and potassium dihydrogen phosphate in the hydrogenation reaction of L -biopterin to prepare a technical solution of (6R)-tetrahydrobiopterin hydrochloride. The method of the present invention uses potassium hydroxide and potassium dihydrogen phosphate, which are inorganic bases, have the advantages of easy removal and can simplify the operation process, and it is unexpectedly found that the method of the present invention can still allow a large reduction in solvent volume. The same product recovery rate is maintained, and the product recovery rate is stabilized, thereby increasing the unit production efficiency in the fixed volume production tank, increasing the operation simplicity, and facilitating industrial large-scale preparation of (6R)-tetrahydrobiopterin. Hydrochloride.

Accordingly, in one aspect, the present invention provides a process for the preparation of (6R)-tetrahydrobiopterin hydrochloride, which comprises reacting L-biopterin in the presence of a platinum-based metal catalyst in a solvent, potassium hydroxide, and Hydrogenation is carried out in an alkaline matrix of potassium dihydrogen phosphate, wherein potassium hydroxide and potassium dihydrogen phosphate control the pH of the basic substrate in the range of from about 10 to about 13 to produce (6R)-tetrahydrobiopterin Hydrochloride.

In particular, the ratio of L -biopterin to solvent of the method of the invention is in the range of from about 1:10 to about 1:1000 (w/v), more specifically from about 1:30 to about 1:100. The range (w/v). Unexpectedly, the method of the present invention maintains substantially equivalent (6R)-tetrahydrobiopterin hydrochloride recovery over a range of such large variations, with the effect of stabilizing product recovery, thereby Increase unit production efficiency.

Preferably, the method of the present invention further comprises the steps of removing the catalyst, acidifying, removing the solvent, and/or recrystallizing.

Various specific embodiments of the invention are described in detail below. Other features of the present invention will be apparent from the following detailed description of various embodiments.

It is believed that those skilled in the art of the invention can <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; Accordingly, the following description is to be considered as illustrative and not restrictive

All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to the invention.

The article "a" as used herein refers to one or more (ie, at least one) grammatical terms of the article.

The method of the present invention is for preparing (6R)-tetrahydrobiopterin hydrochloride, which comprises using L-biopterin in the presence of a platinum-based metal catalyst in a base containing a solvent, potassium hydroxide and potassium dihydrogen phosphate. The hydrogenation reaction is carried out in a substrate in which potassium hydroxide and potassium dihydrogen phosphate control the pH of the basic substrate in the range of from about 10 to about 13 to produce (6R)-tetrahydrobiopterin hydrochloride.

The preparation method of the present invention can be represented by the following reaction formula:

The hydrogenation reaction carried out according to the present invention refers to a chemical reaction in which hydrogen is added to a molecule having a double bond or a multiple bond, thereby hydrogenating L -biopteryrene to form a (6R)-tetrahydrobiopterin.

The hydrogenation reaction carried out according to the present invention is carried out in an alkaline reaction substrate in which potassium hydroxide and potassium dihydrogen phosphate are controlled to have a pH of from about 10 to about 13, more preferably from about 11 to about 12. In general, the organic base is an organic compound having an amine group in the molecule, for example, an amine compound; in contrast, the present invention uses potassium hydroxide and potassium dihydrogen phosphate, does not contain an amine group, and is an inorganic base.

The platinum group metal catalyst in the process of the invention may be any of those known in the art including, but not limited to, platinum black, platinum dioxide, platinum/carbon or platinum/alumina, preferably platinum black or platinum dioxide. . In the process of the present invention, the platinum group metal catalyst can be recovered and reused multiple times, and the recovered catalyst does not reduce the yield of the hydrogenated product.

The hydrogenation reaction in the present invention can be carried out at a hydrogen pressure of from about 1 to about 10 MPa, preferably from about 1 to about 6 MPa, most preferably from about 2 to about 4 MPa; and the reaction temperature is from about 0 to about 40 ° C, Preferably, it is from about 10 to about 30 ° C; and the reaction time is from about 20 to about 50 hours, preferably from about 25 to about 40 hours.

The solvent for carrying out the hydrogenation reaction of the present invention may be any of those known in the art including, but not limited to, water, alcohol or a combination thereof; it is preferably water. Related literature is for example US 4,649,197.

According to the process of the present invention, the ratio of the platinum group metal catalyst, L-biopteryrene and solvent which are subjected to the hydrogenation reaction can be adjusted by the person skilled in the art according to his own knowledge and/or its needs. The weight ratio of the platinum group metal to the L-biopterin is usually from about 1% to about 30%, preferably from about 10% to about 20%. The ratio of platinum metal catalyst to solvent (w:v) is from about 1:100 to about 1:2000; preferably from about 1:200 to about 1:1000; most preferably from about 1:300 to about 1:500. Related literature is for example US 4,595,752.

In particular, according to the process of the present invention, the ratio of L -biopterin to solvent for the hydrogenation reaction is in the range of from about 1:10 to about 1:1000 (w/v), more specifically at about 1:30. To the range of about 1:100 (w/v). Unexpectedly, the method of the present invention maintains substantially equivalent (6R)-tetrahydrobiopterin hydrochloride recovery rates, i.e., between each other, in the range of such large variations. The gap is no more than 5%, and better than 3%. Therefore, the method of the present invention can be used to stabilize product recovery, thereby increasing unit production efficiency in a fixed volume production tank, increasing operational simplicity, and facilitating industrial large-scale preparation of (6R)-tetrahydrobiopterin.

According to the method of the present invention, it further comprises the steps of removing the catalyst, acidifying, removing the solvent, and/or recrystallizing.

In the process of the present invention, the catalyst in the hydrogenation reaction can be removed by any conventional method including, but not limited to, filtration, such as atmospheric filtration or reduced pressure filtration, or centrifugation. Related literature is for example US 4,649,197.

After the catalyst is removed, an inorganic acid or an organic acid may be added for acidification, wherein the inorganic acid may be, but not limited to, hydrochloric acid or sulfuric acid; and the organic acid may be, but not limited to, fumaric acid or tartaric acid. The organic acid acidified product has a pH of from about 0 to about 6, preferably from about 2 to about 5, and the mineral acidified product has a pH of from about 0 to about 3, preferably about 1.

In addition, in the process of the present invention, the solvent may be removed by any conventional method including, but not limited to, atmospheric distillation or vacuum distillation under conditions of heating or no heating.

Then, the solvent may be further used to dissolve the product, including but not limited to an alcohol, an aqueous alcohol solution or a mixture of an aqueous acid solution and an alcohol. The preferred alcohol is methanol, ethanol or isopropanol. Preferably, the acid is hydrochloric acid or sulfuric acid. , tartaric acid or fumaric acid. The mixed volume ratio of water and alcohol of the aqueous alcohol solution is from about 1:10 to about 1:40, preferably from about 1:20 to about 1:30; the mixing volume ratio of the aqueous acid solution and the alcohol is about 1:10. Up to about 1:40, wherein the mixed volume ratio of water and acid of the aqueous acid solution is from about 1:0.02 to about 1:1.

The process of the present invention may further recrystallize the product obtained from the step (6) at least once, thereby obtaining a high purity (6R)-tetrahydrobiopterin hydrochloride.

The so-called high purity (6R)-tetrahydrobiopterin hydrochloride of the present invention means that the percentage of enantiomeric excess (ee) of (6R)-tetrahydrobiopterin hydrochloride is greater than about 99%. It is preferably greater than about 99.5%. The percentage of image isomer excess can be determined by the following formula:

Where [R] is the amount of the major isomer product and [S] is the amount of the minor isomer product.

The recrystallization in the present invention can be carried out in the form of a single solvent (e.g., repeating steps (5) and (6)) or a mixed solvent. The mixed solvent generally consists of two solvents which are miscible in any ratio. One of the solvents has a high solubility to the product and is called a good solvent; the other solvent has a small solubility to the product, which is called a poor solvent. In the operation, the substance to be crystallized is first dissolved in a good solvent, and then a poor solvent is added dropwise thereto, left to cool and crystallized. Related literature such as US 2006/0035900

The good solvent used for recrystallization includes, but is not limited to, water, inorganic acid, organic acid or a mixture thereof, wherein the inorganic acid may be, but not limited to, hydrochloric acid or sulfuric acid; and the organic acid may be, but not limited to, fumaric acid. Or tartaric acid. According to the invention, preferred solvents are water, hydrochloric acid or mixtures thereof. Related literature is for example US 2006/0035900.

The poor solvent used for the recrystallization includes, but is not limited to, an alcohol or an ether, wherein the alcohol may be, but not limited to, methanol, ethanol or isopropanol; and the ether may be, but not limited to, tetrahydrofuran or Oxyhexane, etc. According to the present invention, a preferred poor solvent is methanol, ethanol or tetrahydrofuran. Related literature is for example US 2006/0035900, chemistry letters, 1984, 735-738.

In the process of the invention, the conditions of the different recrystallizations may be the same or different. In a preferred embodiment of the invention, the recrystallization is carried out twice, wherein the ratio of the good solvent to the desired recrystallized (6R)-tetrahydrobiopterin hydrochloride product is from about 1:1 to about 20 : 1 (v: w), preferably from about 3:1 to about 10:1; and the volume ratio of the good solvent to the poor solvent used in the first recrystallization is from about 1:1 to about 1:10, Preferably, the ratio of the good solvent to the poor solvent used in the second recrystallization is from about 10:1 to about 10:20, preferably from about 10:5 to about 10: 15. In the first and second recrystallization operations, the other operating conditions were the same except that the ratio of the good solvent to the poor solvent was large.

When recrystallization is carried out, a certain amount of (6R)-tetrahydrobiopterin hydrochloride seed crystal may be added as needed. The seed crystal may be any (6R)-tetrahydrobiopterin hydrochloride crystal having an excess percentage of any mirror image isomer greater than 99%.

The method of the invention uses potassium hydroxide and potassium dihydrogen phosphate to control the pH of the reaction substrate of the hydrogenation reaction, which can be removed as an inorganic salt by simple post-treatment to increase (6R)-tetrahydrobiopterin. The safety of guanidine hydrochloride in drug use. Moreover, the platinum group metal catalyst in the method of the present invention can be easily recovered and reused to reduce the production cost. Moreover, the method of the present invention can tolerate a greatly varying ratio of L -biopterin to solvent while still maintaining an isotropic product recovery rate, and has the effect of stabilizing product recovery, thereby increasing unit production in a fixed volume production tank. Efficiency, increased ease of operation, and industrialization of large-scale preparation of (6R)-tetrahydrobiopterin.

The invention is hereinafter described in more detail by way of example only, and not by way of limitation.

Example 1

Add 0.05 g of platinum dioxide to 50 mL of water, add 0.5 g of L-biopterin with stirring, adjust the pH to 11.5 with potassium hydroxide and potassium dihydrogen phosphate, and transfer the mixture to the autoclave and charge 4.0 MPa. The hydrogen gas was reacted at 14 ° C for 50 hours, and then the catalyst was filtered off. After adding concentrated hydrochloric acid to adjust pH = 1, the water was distilled off under reduced pressure, and the obtained solid was analyzed by HPLC (6R): (6S) = 5.1:1, and 20 mL was added. Ethanol dissolved in the product, the insoluble inorganic salt was removed by filtration, the filtrate was removed under reduced pressure, dissolved in 2.5 mL of 3M hydrochloric acid, 5 mL of absolute ethanol was added dropwise, seed crystals were added, and the crystals were allowed to stand at 0 ° C to precipitate crystals. The white solid was dissolved in 1.5 mL of 3M hydrochloric acid, and 1.5 mL of absolute ethanol was slowly added dropwise to the solution, and the crystal was slowly precipitated at 0 ° C for 6 h, and the crystals were gradually filtered off, and dried to obtain (6R)-tetrahydrobiopterin hydrochloride white. The crystal was 0.27 g, the purity was >99.5%, the ee value was >99.5%, and the recovery was 41%.

Example 2

1 g of platinum dioxide was added to 1000 mL of water, 10 g of L-biopterin was added with stirring, and the pH was adjusted to 11.5 with potassium hydroxide and potassium dihydrogen phosphate. The mixture was transferred to an autoclave and charged with 4.0 MPa. The hydrogen gas was reacted at 14 ° C for 50 hours, then the catalyst was filtered off, concentrated hydrochloric acid was added to adjust pH = 1, and the water was distilled off under reduced pressure. The obtained solid was analyzed by HPLC (6R): (6S) = 4.2:1, 400 mL of ethanol dissolved product The insoluble inorganic salt was removed by filtration, the filtrate was removed under reduced pressure, and dissolved in 80 mL of 3M hydrochloric acid. After dropwise addition of 160 mL of anhydrous ethanol, seed crystals were added, and the crystals were allowed to stand at 4 ° C to precipitate a crystal. After adding 3 mL of hydrochloric acid to dissolve 50 mL, 40 mL of absolute ethanol was slowly added dropwise to the solution, and the crystal was slowly precipitated at 4 ° C for 6 h, and the crystals were gradually filtered off, and dried to obtain white crystals of (6R)-tetrahydrobiopterin hydrochloride. 3.96 g, purity >99.8%, ee value >99.8%, yield 30%.

Example 3

0.12 g of platinum dioxide has been used once to add 100 mL of water, 1.0 g of L-biopterin is added with stirring, the pH is adjusted to 11.5 with potassium hydroxide and potassium dihydrogen phosphate, and the mixture is transferred to an autoclave. After charging with 4.0 MPa of hydrogen, reacting at 14 ° C for 50 hours, filtering off the catalyst, adding concentrated hydrochloric acid to adjust pH = 1 and then distilling off the water under reduced pressure, and the obtained solid was analyzed by HPLC analysis (6R): (6S) = 4.5:1,400 The product was dissolved in mL ethanol, and the insoluble inorganic salt was removed by filtration. The filtrate was removed under reduced pressure, and dissolved in 6 mL of 3M hydrochloric acid. After dropwise addition of 12 mL of anhydrous ethanol, the crystals were allowed to stand at 4 ° C to precipitate crystals. After adding 3 mL of 3M hydrochloric acid to dissolve, 3 mL of absolute ethanol was slowly added dropwise to the solution, and the crystal was gradually precipitated at 4 ° C for 6 h, and the crystal was gradually precipitated, suction filtered, and dried to obtain white crystal of (6R)-tetrahydrobiopterin hydrochloride. 0.45 g, purity >99.8%, ee value >99.8%, recovery rate 34%.

Example 4

0.06 g of platinum dioxide has been used twice into 50 mL of water, 0.5 g of L-biopterin is added with stirring, the pH is adjusted to 11.5 with potassium hydroxide and potassium dihydrogen phosphate, and the mixture is transferred to an autoclave. After charging with 4.0 MPa of hydrogen, the reaction was carried out at 14 ° C for 50 hours, the catalyst was filtered off, concentrated hydrochloric acid was added to adjust pH = 1, and the water was distilled off under reduced pressure. The obtained solid was analyzed by HPLC (6R): (6S) = 4.5: 1,400 mL of ethanol was dissolved in the product, and the insoluble inorganic salt was removed by filtration. The filtrate was removed under reduced pressure, dissolved in 2.5 mL of 3M hydrochloric acid, and 5 mL of anhydrous ethanol was added dropwise, and then crystals were allowed to stand at 4 ° C to precipitate crystals. After solid solution was added to 1.5 mL of 3M hydrochloric acid, 1 mL of absolute ethanol was slowly added dropwise to the solution, and the crystal was gradually precipitated at 4 ° C for 6 h, and the crystal was precipitated by suction filtration to obtain (6R)-tetrahydrobiopterin hydrochloride white. The crystal was 0.23 g, the purity was >99.5%, the ee value was >99.5%, and the recovery was 35%.

Example 5

0.1 g of platinum dioxide was added to 30 to 100 ml of water (as shown in Table 1), and 1 g of L-biopterin was added with stirring, and then potassium hydroxide and potassium dihydrogen phosphate were added to adjust the pH to 11.4. The mixed solution was placed in an autoclave and reacted under a hydrogen pressure of 4.0 MPa at 14 ° C for 50 hours. After the reaction, the catalyst in the solution is filtered off, and concentrated hydrochloric acid is added to adjust the pH of the filtrate to 1, and then the filtrate is distilled under reduced pressure to remove water to obtain a solid, and the obtained solid is analyzed by HPLC according to the preceding example. : 6S reaction rate and recrystallization in the same step to calculate the pure yield. Table 1 shows the relevant reaction rates and pure product yields.

As shown in Table 1, according to the method of the present invention, 1 g of L-biopterin was also used, and almost equivalent (6R)-tetrahydrobiopterin was maintained over a range of solvent volumes ranging from 30 to 100 ml. The hydrochloride recovery rate (29-32%) has the effect of stabilizing product recovery, which increases the unit production efficiency in the fixed volume production tank, increases the operation simplicity, and contributes to the industrial large-scale preparation of (6R)-tetrahydrogen. Biological paralysis.

Those skilled in the art will be able to make changes and modifications in accordance with the embodiments without departing from the spirit of the invention. It is to be understood that the invention is not to be limited by the scope of the embodiments disclosed herein,

Claims (11)

A method for preparing (6R)-tetrahydrobiopterin hydrochloride, which comprises carrying out L-biopterin in an alkaline matrix containing a solvent, potassium hydroxide and potassium dihydrogen phosphate in the presence of a platinum-based metal catalyst A hydrogenation reaction in which potassium hydroxide and potassium dihydrogen phosphate control the pH of the basic substrate in the range of 10 to 13, and acidification is carried out by adding hydrochloric acid to produce (6R)-tetrahydrobiopterin hydrochloride. The preparation method according to Item 1, wherein the solvent is selected from the group consisting of water, alcohol, and a combination thereof. The production method according to the first aspect of the patent application, wherein the hydrogenation reaction is carried out at a hydrogen pressure of from 1 to 10 MPa. The preparation method according to the first aspect of the invention, wherein the temperature of the hydrogenation reaction is from 0 to 40 °C. The preparation method according to the first aspect of the patent application, wherein the hydrogenation reaction is carried out for 20 to 50 hours. The preparation method according to claim 1, wherein the ratio of the L -biopterin to the solvent is in the range of 1:10 to 1:1000 (w/v). The preparation method according to claim 6, wherein the ratio of the L -biopterin to the solvent is in the range of 1:30 to 1:100 (w/v). The preparation method according to any one of claims 1 to 7, which can be used for stabilizing the recovery rate of (6R)-tetrahydrobiopterin hydrochloride, thereby increasing unit production efficiency. The preparation method according to any one of claims 1 to 7, which further comprises removing the catalyst by filtration after hydrogenation of the L-biopterin. The preparation method according to claim 9 of the patent application, which further comprises a concentration step of removing the solvent under reduced pressure to obtain a concentrated product. The preparation method according to claim 10, further comprising recrystallizing the concentrated product.