Method for preparing zalvizepam chiral intermediate by chemical-enzyme method

Abstract

The invention discloses a method for preparing a zalvizepam chiral intermediate by a chemical-enzyme method. According to the present invention, the aromatic hydrocarbon fragment of the compound III is directly removed through the concentrated sulfuric acid or the concentrated hydrochloric acid to obtain the ketonic acid compound IV, and then the ketonic acid compound IV reacts with the transaminase to obtain the zavazepam chiral intermediate I. The route has characteristics of simple operation and low cost, and is suitable for industrial production.

Description

Technical fields:

[0001] This invention belongs to the field of biocatalysis technology, specifically relating to a chemical-enzymatic method for preparing zavigipan chiral intermediates. Background technology:

[0002] Zavegepant is a calcitonin gene-related peptide (CGRP) receptor antagonist developed by Bristol-Myers Squibb. On March 9, 2023, Zavegepant was approved by the U.S. FDA for the treatment of acute migraine in adults with or without aura. This product is also the first CGRP receptor antagonist nasal spray for the acute treatment of migraine in adults.

[0003] The structure of zavigepan contains only one chiral site, and the control of this chirality is the key and difficult point in the synthesis of zavigepan. As shown by the retrosynthetic analysis in Scheme 1, this chiral site is mainly introduced by compound I. The preparation of compound I will directly affect the chirality of zavigepan and its commercialization.

[0004]

[0005] Patent WO2022172829A1 discloses a method for preparing compound I using multi-enzyme catalysis, as shown in Scheme 2. In this method, compound 1 undergoes a two-step reaction to yield the enzymatic substrate compound 3, which is then hydrolyzed by hydantoinase, decarbamoylase, and racemic hydantoin to generate compound I. This reaction involves three enzymes, requires a relatively large amount of cells, and achieves a yield of 92.4%, a conversion rate of 96.7%, and an ee value of 99.0%.

[0006]

[0007] The literature *Organic Process Research & Development*, 2012, 16(12), 1953-1966, reports a method for preparing compound I, the route of which is shown in Scheme 3. This method uses compound II as a starting material, first reacting it with hippuric acid... The reaction yielded compound III, which then underwent an alcoholysis ring-opening reaction with sodium methoxide at a controlled temperature below 30°C. Following this, it reacted with HCl at 100°C for 6 hours to yield hydrolysis product IV. Finally, approximately 30 g / L of compound IV was reacted with D-transaminase for 72 hours to yield compound I. The yield of this enzymatic reaction step was 77%, with an ee value of 99%. This route involves complex dearomatication, involving two steps of alcoholysis and hydrolysis, with the reaction conditions being initially low temperature followed by high temperature, and a yield of approximately 70%, making it unsuitable for industrial production.

[0008]

[0009]

[0010] In existing technologies, the preparation methods for zavigipan intermediate I are costly, cumbersome, and unsuitable for industrialization. Therefore, we need to develop a low-cost, simple, safe, environmentally friendly, and industrially applicable preparation method. Summary of the Invention:

[0011] The purpose of this invention is to address the shortcomings of existing technologies by providing a simple and easily industrialized method for preparing zavigipan chiral intermediate I.

[0012] The technical solution adopted in this invention is shown in Scheme 4:

[0013]

[0014] This invention provides a method for preparing zavigipan chiral intermediate I, specifically comprising the following steps: under conditions of 50–110°C, compound III reacts with concentrated hydrochloric acid or concentrated sulfuric acid to generate compound IV, and then compound IV is converted into compound I under the catalysis of a transaminase, wherein the transaminase is selected from ES-ATA-153 or ES-ATA-156.

[0015] Furthermore, the volume ratio of compound III to concentrated hydrochloric acid or concentrated sulfuric acid is 1:4 to 1:15, preferably 1:8 to 1:10.

[0016] Furthermore, the compound IV and transaminase undergo an enzymatic reaction in a buffer solution at a temperature of 20–60°C.

[0017] Furthermore, the transaminase is derived from Arthrobacter sp., Actinobacteria sp., Rhodobacter sp., Vitreoscillastercoraria DSM 513, Chromobacterium violaceum, or their homologs.

[0018] Furthermore, the transaminase participates in the catalytic reaction in the form of transaminase powder, transaminase solution, transaminase homogenate, transaminase-containing cells, immobilized cells, immobilized enzymes, etc., with transaminase cells being the preferred form.

[0019] Furthermore, the transaminase expression receptor strain is selected from Escherichia coli, yeast, Streptomyces or Bacillus subtilis.

[0020] Furthermore, the transaminase is selected from Shangke Biomedical (Shanghai) Co., Ltd.

[0021] Furthermore, the preparation method of compound III is shown in Scheme 5, wherein compound II reacts with hippuric acid. The reaction yields compound III.

[0022]

[0023] Furthermore, compound I can be used to prepare zavigipan.

[0024] The beneficial effects of this invention are that it discloses a new method for preparing zavigepan chiral intermediate I. This invention directly removes the aromatic fragment of compound III by concentrated sulfuric acid or concentrated hydrochloric acid to obtain keto acid compound IV, combining the complex two-step alcoholysis and hydrolysis reactions into a one-step reaction with a reaction yield of up to 85%. Then, it reacts with transaminase to obtain compound I. This route is simple to operate, low in cost, and more suitable for industrial production. Attached image description:

[0025] Figure 1 Example 3: HPLC chromatogram of substrate transformation

[0026] Figure 2 Example 5: HPLC chromatogram of substrate transformation Detailed implementation method:

[0027] The technical content of the present invention will be further described below with reference to specific embodiments, in order to better understand the content of the present invention, but the scope of protection of the present invention is not limited thereto.

[0028] Example 1: Preparation of Compound III

[0029] 31.1L of toluene, compound II (2595g, 16.22mol, 1.0eq), potassium acetate (2225.1g, 22.67mol, 1.4eq), hippuric acid (5800g, 32.37mol, 2eq), and 7.8L of acetic anhydride were added sequentially to a 50L reactor. After the addition was complete, the system turned into a dark red turbid liquid. The temperature was raised to 80℃ and the reaction was carried out for 3 hours. After the reaction was completed, the mixture was cooled to room temperature and filtered. The filter cake was taken and 30.0L of water was added and the mixture was stirred for 1 hour. Then it was filtered again. The resulting wet product was used directly for the next reaction.

[0030] Example 2 Preparation of Compound IV

[0031] Add 24.5 mL of 50% sulfuric acid and compound III (4.9 g, 1.6 mol, 1.0 eq) from Example 1 to a 100 mL reaction flask, then slowly heat to 85 °C. During the heating process, a large number of bubbles will be generated. Continue stirring for 8 hours. After the reaction is complete, cool to room temperature, filter, and wash the filter cake with 10 mL of water. Slurry the filter cake with a mixed solvent of isopropanol and water for 2 hours, then filter. Dry the filter cake under vacuum at 45 °C to obtain 2.82 g of product, with a yield of 80.0%.

[0032] Example 3 Preparation of Compound IV

[0033] Add 1.5 L of concentrated hydrochloric acid and compound III (214.0 g, 0.71 mol, 1.0 eq) from Example 1 to a 5 L reaction flask. Then slowly heat to 90 °C. During heating, a large amount of bubbles will be generated. Continue stirring for 8 hours. After the reaction is complete, cool to room temperature, filter, and wash the filter cake with 230 mL of water. Pulverize the filter cake with a mixture of isopropanol and water for 2 hours, then filter again. Dry the filter cake under vacuum at 45 °C to obtain 128.0 g of product, with a yield of 83.1%. The substrate conversion HPLC chromatogram is shown below. Figure 1 As shown.

[0034] Example 4 Preparation of Compound IV

[0035] 25.0 L of concentrated hydrochloric acid and compound III (5.0 kg, 16.48 mol, 1.0 eq) from Example 1 were added to a 50 L reactor. The mixture was then slowly heated to 105 °C. During the heating process, a large number of bubbles were generated. The mixture was stirred for 8 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the filter cake was washed with 10 L of water. The filter cake was then slurried with a mixture of isopropanol and water for 2 hours, filtered again, and vacuum dried at 45 °C to obtain 2949.4 g of product, with a yield of 82.0%.

[0036] Example 5 Preparation of Compound I

[0037] 1.57 L of water, isopropylamine (135.4 g, 2.30 mol, 5.0 eq), and compound IV (100.0 g, 0.46 mol, 1.0 eq) were added to a 5 L reactor. The pH of the system was adjusted to 8.0–8.5 with concentrated hydrochloric acid, and the system turned into a light brown clear liquid. Then, a prepared pyridoxal phosphate solution (50.0 mL, 2.0 g / L) and transaminase cells (Shanghai ES-ATA-153, 375.0 mL) were added sequentially to the system. The mixture was stirred at 32 °C for 48 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the filter cake was washed with 110 mL of water. The filter cake was then vacuum dried at 45 °C to obtain 91.8 g of off-white solid, with a yield of 91.4%. The substrate transformation HPLC chromatogram is shown in [Figure number missing]. Figure 2 As shown.

[0038] Example 6 Preparation of Compound I

[0039] 32.45 L of purified water, isopropylamine (2800 g, 47.2 mol, 5.0 eq), and compound IV (2060 g, 9.45 mol, 1.0 eq) were added to a 50 L reactor. The pH of the system was adjusted to 8.0–8.5 with concentrated hydrochloric acid, and the system turned into a light brown clear liquid. Then, a prepared pyridoxal phosphate solution (1030.0 mL, 2.0 g / L) and transaminase homogenate (Shanghai ES-ATA-156, 7.7 L) were added to the system sequentially. The mixture was stirred at 32 °C for 48 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the filter cake was washed with 2.5 L of water. The filter cake was dried under vacuum at 45 °C to obtain 1873 g of off-white solid, with a yield of 90.5%.

Claims

1. A method for preparing zavigepan chiral intermediate compound I using a chemical-enzymatic method, characterized in that, Under conditions of 50–110℃, compound III reacts with concentrated hydrochloric acid or concentrated sulfuric acid to form compound IV. Then, compound IV is converted into compound I under the catalysis of transaminase. The reaction formula is shown below: The transaminases are selected from ES-ATA-153 and ES-ATA-156.

2. The preparation method according to claim 1, characterized in that, The volume ratio of compound III to concentrated hydrochloric acid or concentrated sulfuric acid is 1:4 to 1:

15.

3. The preparation method according to claim 1, characterized in that, The transaminase participates in the catalytic reaction in the form of transaminase powder, transaminase clear solution, transaminase homogenate, transaminase-containing cells, immobilized cells, immobilized enzymes, etc.

4. The preparation method according to claim 1, characterized in that, The transaminase expression receptor strains are selected from Escherichia coli, yeast, Streptomyces or Bacillus subtilis.

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