Method for preparing (S)-(-)-1-amphetamine

Abstract

The invention discloses a method for preparing (S)-(-)-1-amphetamine. According to the method, propiophenone serves as a substrate and is converted into (S)-(-)-1-amphetamine under the catalytic action of imine reductase and ammonia water, the conversion rate is larger than or equal to 99%, and the ee value of the product is larger than or equal to 99%. The method disclosed by the invention is simple to operate and high in atom economy, and can be used for industrial production.

Description

Technical field:

[0001] The invention belongs to the technical field of biocatalysis, and in particular relates to a method for preparing (S)-(-)-1-amphetamine. Background technology:

[0002] (S)-(-)-1-amphetamine, with the structural formula shown in I and CAS number 3789-59-1, is an important pharmaceutical intermediate that can be used to prepare neurokinin-3 receptor (NK3R) antagonists, such as Talnetant for the treatment of schizophrenia, Pavinetant for the treatment of hot flashes and polycystic ovary syndrome, etc. In the future, this compound can be used to prepare more new drugs.

[0003]

[0004] Patent CN104630171A discloses a preparation route for (S)-(-)-1-amphetamine as shown in Scheme 1. In this route, (RS)-1-amphetamine is used as a substrate. Under the action of R-aminotransferase from Trichoderma reesei QM6a, (S)-(-)-amphetamine is obtained by chiral resolution. The conversion rate is 50% and the ee value is 99%. In this route, the material loss in the resolution step is large and the yield is low.

[0005]

[0006] The preparation route of (S)-(-)-1-amphetamine disclosed in patent CN107001312A is shown in Scheme 2. The route uses phenylacetone as a substrate and reacts with Pd 0 -AmP-MCF and R-transaminase combined heterogeneous / enzyme-assisted catalytic reaction system undergoes reductive amination and kinetic resolution reaction to obtain (S)-(-)-amphetamine with an ee value of 99% in a yield of 95%. 0 -AmP-MCF is complex to make, difficult to preserve, and not suitable for industrial production.

[0007]

[0008] The preparation route of (S)-(-)-1-amphetamine disclosed in patent CN112481229B is shown in Scheme 3. The substrate is phenylacetone, and an enzymatic reaction occurs under the action of transaminase and pyruvate decarboxylase. After 48 hours of conversion, the substrate conversion rate is 94.4% and the ee value is 99%.

[0009]

[0010] Therefore, we need to develop a preparation method that is simple to operate, high in yield, safe and environmentally friendly, and suitable for industrialization. Summary of the invention:

[0011] The object of the present invention is to provide a method for preparing (S)-(-)-1-amphetamine which is simple to operate and easy to industrialize in view of the deficiencies in the prior art.

[0012] The technical solution adopted by the present invention is shown in Scheme 4:

[0013]

[0014] The invention provides a method for preparing (S)-(-)-1-amphetamine, which specifically comprises the following steps: taking phenylacetone as a substrate and converting it into (S)-(-)-1-amphetamine under the catalytic action of ammonia water, imine reductase and glucose dehydrogenase.

[0015] Furthermore, the phenylpropiotone first reacts with aqueous ammonia to generate imine, and then is converted into (S)-(-)-1-amphetamine under the action of imine reductase.

[0016] Furthermore, aqueous ammonia needs to be added in the reaction, and the amount of aqueous ammonia used is 1.0 to 8.0 equivalents, preferably 3.0 to 5.0 equivalents.

[0017] Furthermore, the imine reductase participates in the catalytic reaction in the form of imine reductase enzyme powder, imine reductase enzyme solution, imine reductase homogenous solution, imine reductase lyophilized powder, cells containing imine reductase, etc., preferably imine reductase homogenous solution and lyophilized powder.

[0018] Furthermore, the imine reductase is selected from the imine reductases ES-IRED-101 to ES-IRED-117 produced by Shangke Biopharmaceuticals (Shanghai) Co., Ltd., preferably ES-IRED-103, ES-IRED-112, and ES-IRED-115.

[0019] Furthermore, the imine reductase expression strain is selected from Escherichia coli.

[0020] Furthermore, the glucose dehydrogenase is selected from glucose dehydrogenase ES-GDH-101 to ES-GDH-110 produced by Shangke Biopharmaceutical (Shanghai) Co., Ltd., preferably ES-GDH-110.

[0021] Furthermore, coenzymes can be added to the reaction system to promote the reaction. When cells containing imine reductase are used, a small amount of coenzymes are contained in the cells, and the coenzymes may not be added at this time. In some cases, the prepared imine reductase powder also contains a small amount of coenzymes, and the coenzymes may not be added at this time. However, coenzymes can also be added to the reaction system to further promote the reaction. When coenzymes are added to the reaction system to promote the reaction, the coenzymes are selected from NAD + , NADH, NADP + , NADPH or a combination thereof, preferably NADP + .

[0022] Furthermore, the concentration of the added coenzyme is 0.02 to 0.4 g / L, preferably 0.04 to 0.2 g / L.

[0023] Furthermore, the coenzymes used in this technical solution are all selected from the coenzyme products sold by Shangke Biopharmaceuticals (Shanghai) Co., Ltd.

[0024] Furthermore, a cosolvent needs to be added in the reaction, and the cosolvent is selected from methanol, ethanol, isopropanol, tert-butanol, ethyl acetate, tetrahydrofuran, methyl tert-butyl ether, isopropyl ether, acetone, acetonitrile, toluene, cyclohexane, n-hexane, n-heptane, 2-methyl-tetrahydrofuran, dimethyl sulfoxide, preferably isopropyl ether, cyclohexane, n-hexane, n-heptane, and dimethyl sulfoxide.

[0025] Furthermore, the reaction time is 1 h to 48 h, preferably 24 h to 32 h.

[0026] Furthermore, the reaction needs to be controlled at a pH of 6.0 to 12.0, preferably at a pH of 8.0 to 9.0.

[0027] Furthermore, the reaction temperature is 20°C to 60°C, preferably 30°C to 40°C.

[0028] The beneficial effect of the present invention is that the present invention provides a method for preparing (S)-(-)-1-amphetamine, wherein phenylacetone is converted into (S)-(-)-1-amphetamine under the action of ammonia water and imine reductase, the substrate conversion rate is ≥99%, the product ee value is ≥99%, the method is simple to operate, has high atom economy, and can be used for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Example 7 Product purity HPLC analysis chart.

[0030] Figure 2 HPLC analysis of chiral purity of the product in Example 7. DETAILED DESCRIPTION

[0031] The technical content of the present invention is further described below in conjunction with specific embodiments, the purpose of which is to provide a better understanding of the content of the present invention, but the protection scope of the present invention is not limited thereto.

[0032] Example 1 Screening of Imine Reductase

[0033] The enzymes in the imine reductase enzyme library of Shangke Biopharmaceuticals (Shanghai) Co., Ltd. were used to screen the reaction of the substrate. 0.1g of phenylacetone and 0.33mL of isopropyl ether were added to the system in sequence. After mixing, an ammonia solution was added dropwise. The ammonia solution consisted of 0.15g of 25% ammonia water and 1.33mL of 0.5M potassium phosphate buffer with pH=8. After the addition was completed, the solution was stirred evenly. Imine reductase, glucose dehydrogenase and coenzyme NADP were added continuously. The pH was adjusted to 8.5 with 5% hydrochloric acid. The reaction was stirred at 35°C for 24 hours. After the reaction was completed, HPLC detection and analysis were performed. The results showed that the best enzymes were imine reductases ES-IRED-103, ES-IRED-112, and ES-IRED-115, with a conversion rate of ≥70%, and chiral HPLC detection showed that the product ee value was ≥98.0%.

[0034] Example 2 Optimization of reaction conditions --- selection of co-solvent

[0035] In order to optimize the effect on product synthesis during the conversion process, the cosolvents in the screened imine reductase reaction process were optimized respectively. The cosolvents included isopropyl ether, cyclohexane, n-hexane, n-heptane, dimethyl sulfoxide, ethanol, and ethyl acetate. The other reaction conditions were the same as those in Example 1. The reaction results were analyzed. The specific data are shown in Table 1. The reaction results show that the conversion effect is better when isopropyl ether, cyclohexane, and n-hexane are used as cosolvents.

[0036] Table 1 Optimization results of cosolvent

[0037]

[0038] Example 3 Optimization of reaction conditions --- selection of temperature

[0039] In order to optimize the effect of parameters on product synthesis during the conversion process, the temperature during the reaction of the screened imine reductase was optimized. The temperature was set in the range of 20°C to 50°C, and the reaction was carried out for 24 hours. The other reaction conditions were the same as those in Example 1. The reaction results were analyzed. The specific data are shown in Table 2. The reaction results show that the conversion effect is better when the temperature is 30 to 40°C.

[0040] Table 2 Optimization results at different temperatures

[0041]

[0042] Example 4 Optimization of reaction conditions --- pH selection

[0043] In order to optimize the effect of parameters on product synthesis during the conversion process, the pH of the screened imine reductase reaction process was optimized, and the pH was set between 7.0 and 11.0. The reaction was carried out for 24 hours. The other reaction conditions were the same as those in Example 1. The reaction results were analyzed. The specific data are shown in Table 3. The reaction results showed that the conversion effect was better when the pH was 8.0 to 9.0.

[0044] Table 3 Optimization results of different pH values

[0045]

[0046] Example 5 Optimization of reaction conditions --- dosage of ammonia water

[0047] In order to optimize the effect on product synthesis during the conversion process, the amount of ammonia water used in the screened imine reductase reaction process was optimized, and the amount of ammonia water was set at 1.0 to 8.0 equivalents. The other reaction conditions were consistent with Example 1. The reaction results were analyzed. The specific data are shown in Table 4. The reaction results show that the conversion effect is better when 3.0 to 5.0 equivalents of ammonia water are added.

[0048] Table 4 Optimization results of ammonia dosage

[0049]

[0050] Example 6 Optimization of reaction conditions---reaction time

[0051] In order to optimize the effect on product synthesis during the conversion process, the reaction time of the screened imine reductase reaction process was optimized, and the reaction time was set at 1 to 48 hours. The other reaction conditions were consistent with those in Example 1. The reaction results were analyzed. The specific data are shown in Table 5. The reaction results show that the conversion effect is better when the reaction time is 24 to 32 hours.

[0052] Table 5 Optimization results of reaction time

[0053]

[0054] Example 7 Preparation of (S)-(-)-1-amphetamine

[0055] Into the three-mouth reaction flask, 45.0g of phenylacetone and 150mL of normal hexane were added successively. After mixing, an aqueous ammonia solution was added dropwise, which was composed of 115.0g of 25% ammonia water and 600mL of 0.5M potassium phosphate buffer with pH=8. After completion of the dropwise addition, the mixture was stirred evenly. Imine reductase (ES-IRED-112), glucose dehydrogenase (ES-GDH-110) and coenzyme NADP were added. The pH=9.0 was adjusted with 5% hydrochloric acid. The reaction was stirred at 35°C for 32 hours. After TLC monitoring showed that the substrate disappeared, cyclohexane was removed by distillation under reduced pressure, enzyme was removed by ultrafiltration, and the pH of the filtrate was adjusted to 12. The mixture was extracted 3 times with n-butanol and (S)-(-)-1-amphetamine was obtained by distillation under reduced pressure. The conversion rate was 99.9%, the yield was 95%, the product purity was 98.5%, the ee value was 99.8%, and the product purity HPLC atlas was shown in Figure 5. Figure 1 As shown, the chiral purity HPLC spectrum of the product is shown in Figure 2 shown.

Claims

1. A method for preparing (S)-(-)-1-amphetamine, characterized in that, With phenylacetone as substrate, it is converted into (S)-(-)-1-amphetamine under the catalysis of ammonia, imine reductase and glucose dehydrogenase. The reaction equation is as follows:

2. The preparation method according to claim 1, characterized in that The amount of ammonia water used is 1.0 to 8.0 equivalents.

3. The preparation method according to claim 1, characterized in that: The imine reductase participates in the catalytic reaction in the form of enzyme powder, enzyme solution, homogenized solution, freeze-dried powder, cells containing the enzyme, and the like.

4. The preparation method according to claim 1, characterized in that: The imine reductase is selected from the imine reductase ES-IRED-101 to ES-IRED-117 produced by Shangke Biopharmaceutical (Shanghai) Co., Ltd.

5. The method according to claim 1, characterized in that The imine reductase is selected from genetically engineered Escherichia coli or yeast.

6. The preparation method according to claim 1, characterized in that: The glucose dehydrogenase is selected from glucose dehydrogenase ES-GDH-101 to ES-GDH-110 produced by Shangke Biopharmaceutical (Shanghai) Co., Ltd.

7. The preparation method according to claim 1, characterized in that: The coenzyme is selected from NAD + , NADH, NADP + , NADPH or a combination thereof.

8. The preparation method according to claim 1, characterized in that: A cosolvent needs to be added in the reaction, and the cosolvent is selected from methanol, ethanol, isopropanol, tert-butanol, ethyl acetate, tetrahydrofuran, methyl tert-butyl ether, isopropyl ether, acetone, acetonitrile, toluene, cyclohexane, n-hexane, n-heptane, 2-methyl-tetrahydrofuran, and dimethyl sulfoxide.

9. The preparation method according to claim 1, characterized in that: The reaction temperature is 20°C to 60°C.

10. The preparation method according to claim 1, characterized in that: The reaction needs to control the pH to be 6.0-12.0.

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