A high-throughput microchannel continuous synthesis of N 6 - benzoyl-d-adenosine

Abstract

The application discloses a kind of high-flux microchannel continuous synthesis N 6 - benzoyl-D-adenosine method. With D-adenosine, trimethylchlorosilane and benzoyl chloride as raw material, pyridine as solvent and acid binding agent, three-stage microchannel reactor is used, and hydroxy trimethylsilyl group protection, N 6 Site selective benzoylation, in-situ desilylation and selective removal of N 6 ,N 6 -dibenzoyl byproduct reaction are sequentially and continuously completed. The target product is obtained after neutralization by hydrochloric acid, cooling and crystallization, centrifugation and drying. The method shortens the traditional kettle reaction time from 12-18 h to 20-60 min; the temperature control precision is high, and there is no local overheating; the HPLC purity is ≥99.0%, the maximum single impurity is ≤0.3%, and the yield is more than 90.0%. The application has the advantages of continuous stability, safety and efficiency, controllable impurities, easy industrialization and the like, and solves the technical defects of high impurity, long cycle, large yield fluctuation and high risk of amplification in traditional process.

Description

Technical Field

[0001] This invention belongs to the field of nucleoside drug intermediate synthesis technology, specifically relating to a high-throughput microchannel continuous flow method for preparing N... 6 The method for benzoyl-D-adenosine. Background Technology

[0002] N 6 -Benzoyl-D-adenosine is a key intermediate for small nucleic acid drugs, antiviral drugs, and antitumor active pharmaceutical ingredients. Current industrial production mostly employs a traditional batch process using pyridine as a solvent, sequentially performing silicon-based protection, benzoylation, ammonia deprotection, neutralization, crystallization, and purification to obtain the product. CN 104151384 B et al. reported N... 6 While the method for preparing benzoyl-D-adenosine represents a significant improvement over traditional processes, the traditional process still suffers from several drawbacks: the silicon-based protection and benzoylation are strongly exothermic reactions, leading to uneven mixing in the batch process, localized overheating, and the easy formation of dibenzoyl byproducts, resulting in low product purity; the reaction cycle is as long as 12–18 hours, and a concentration step is unavoidable in post-processing, resulting in low production efficiency; mass and heat transfer deteriorates after scale-up, leading to large yield fluctuations and poor stability; multiple batch operations pose high safety risks and generate large amounts of waste.

[0003] Microchannel reactors offer advantages such as large specific surface area, high heat exchange efficiency, uniform mixing, precise residence time, and small liquid holdup, making them particularly suitable for the synthesis of highly exothermic and selective nucleosides, and ideal for industrial production. Currently, the entire process of silicon-based protection-benzoylation-deprotection is integrated into microchannels for the continuous preparation of N... 6 The method for benzoyl-D-adenosine has not been publicly reported.

[0004] Invention Content

[0005] This invention patent overcomes the shortcomings of existing technologies and provides a continuous, rapid, high-purity, high-yield, safe, environmentally friendly, and industrially scalable high-throughput microchannel synthesis method for N. 6 The method for benzoyl-D-adenosine.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a high-throughput microchannel continuous synthesis method for N 6 The method for benzoyl-D-adenosine includes the following steps:

[0007] S1 Material Preparation:

[0008] Liquid A: Control the temperature at 15-25℃, add D-adenosine, DMF (N,N-dimethylformamide), and pyridine to the reactor, start stirring, and protect with nitrogen; wherein, the volume ratio of DMF to pyridine is 1:1, and the concentration of D-adenosine in the mixed solvent is 0.4mol / L-0.6mol / L;

[0009] Liquid B: Trimethylchlorosilane:

[0010] Liquid C: Benzoyl chloride;

[0011] Liquid D: 6N~10N sodium hydroxide solution:

[0012] Liquid E: Hydrochloric acid.

[0013] S2 First Microchannel: Silicon-based Protection

[0014] Liquid A and liquid B are simultaneously introduced into the first microchannel via a metering pump, and the temperature is maintained at 0℃~10℃ for 3min~10min to complete the protection of adenosine hydroxysilyl groups.

[0015] S3 Second Microchannel: N 6 -benzoylation

[0016] The material exiting from the first microchannel enters the second microchannel, mixes with liquid C, and is held at 5℃~20℃ for 5min~15min to complete the N2 process. 6 Selective benzoylation.

[0017] S4 Third Microchannel: Desilicone and Debenzoyl Groups:

[0018] The material exiting the second microchannel enters the third microchannel and mixes with liquid D. It is kept at −5℃~10℃ for 5min~12min to remove the silicon group and convert the dibenzoyl byproduct into the monobenzoyl product. The amount of OH⁻ in liquid D is 2.0~3.0 equivalents of the molar amount of D-adenosine to ensure complete removal of the silicon group and inhibit the residue of dibenzoyl byproduct.

[0019] S5 Neutralization and Post-processing:

[0020] The third microchannel feed solution E is neutralized with hydrochloric acid to pH 6.5–7.0, and then cooled to 0–5°C to induce crystallization. The solvent used for crystallization is a mixture of purified water and acetonitrile, wherein the amount of purified water is 0.5–1.0 times the volume of the reaction solution, and the amount of acetonitrile is 1.5–2.5 times the volume of the reaction solution, preferably with a volume ratio of 1:2. After crystallization, the solution is centrifuged and dried to obtain N. 6 -benzoyl-D-adenosine.

[0021] Material molar ratio: D-adenosine: trimethylchlorosilane: benzoyl chloride = 1 : 3.2~4.0 : 1.25~1.6; OH⁻ dosage: 2.0~3.0 equivalents of the molar amount of D-adenosine.

[0022] First microchannel: 0℃~10℃, stay for 3min~10min;

[0023] Second microchannel: 5℃~20℃, stay for 5min~15min;

[0024] Third microchannel: −5℃~10℃, stay for 5min~12min;

[0025] Adjust the pH of the reaction system to 6.5–7.0;

[0026] Drying: Vacuum drying at 40℃~45℃, moisture content ≤1.0%.

[0027] Microchannel system: Composed of three microchannel segments connected in series: silicon-based protection, benzoylation, and deprotection;

[0028] Materials: Glass, silicon carbide, or 316L lined with PTFE, with enhanced mixing structure within the microchannels to improve mass transfer efficiency. Attached Figure Description

[0029] Figure 1 This invention provides a high-throughput microchannel synthesis method for N 6 A schematic diagram of the benzoyl-D-adenosine process flow. The diagram illustrates the feed paths of liquids A, B, C, D, and E, as well as the series connection relationship and material flow direction of the three microchannels (first, second, and third).

[0030] Figure 2 N of the present invention 6 HPLC liquid phase of benzoyl-D-adenosine; Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1: As Figures 1-2As shown, this invention provides a technical solution: 100 g of D-adenosine raw material (0.328 mmol) dissolved in 100 mL of DMF and 100 mL of pyridine (volume ratio 1:1, D-adenosine concentration 0.5 mol / L) is transported to mixer 1 via pipeline A using a metering pump. Trimethylchlorosilane (146 g) is transported to mixer 1 via pipeline B (mixer 1 is placed in a low-temperature cold well at 2°C). After mixing, the mixture is retained for 3 minutes. Then, the mixture is transported to mixer 2, and simultaneously, benzoyl chloride (79 g) is transported to mixer 2 via pipeline C (mixer 2 is placed in circulating cooling water at 5°C). After mixing, the mixture is retained for 5 minutes. Then, the mixture is transported to mixer 3, and simultaneously, 10 N sodium hydroxide solution (67 g) is transported to mixer 3 via pipeline D (mixer 3 is placed in a low-temperature cold well at −5°C). The mixture is retained for 5 minutes at −5°C.

[0033] The 10N sodium hydroxide solution has a density of 1.33 g / mL, and 67 g of this solution corresponds to a volume of 50.4 mL, containing 0.504 mol of NaOH, i.e., 0.504 mol of OH⁻. Based on D-adenosine (0.328 mol), the amount of OH⁻ used is 1.54 equivalents. To ensure process robustness, the actual amount of OH⁻ used is 2.0–3.0 equivalents, corresponding to 65–98 g of 10N NaOH solution. In this embodiment, by extending the residence time in the third microchannel (5 min) and controlling the low temperature (−5℃), complete desilication and selective hydrolysis were still achieved at 1.54 equivalents, with a yield of 94.6%, purity of 99.8%, and a maximum single impurity of 0.088%.

[0034] Example 2: 100 g of D-adenosine (0.328 mmol) dissolved in 100 mL of DMF and 100 mL of pyridine (volume ratio 1:1, D-adenosine concentration 0.5 mol / L) was pumped to mixer 1 via line A. 146 g of trimethylchlorosilane was pumped to mixer 1 via line B (mixer 1 was placed in a cryogenic well at 5°C). After mixing, the mixture was held for 9 minutes. Then, the mixture was pumped to mixer 2, while 79 g of benzoyl chloride was pumped to mixer 2 via line C (mixer 2 was placed in circulating cooling water at 20°C). After mixing, the mixture was held for 13 minutes. Then, the mixture was pumped to mixer 3, while 88 g of 8N sodium hydroxide solution was pumped to mixer 3 via line D (mixer 3 was placed in a cryogenic well at −5°C). The mixture was held at −5°C for 14 minutes.

[0035] The 8N sodium hydroxide solution has a density of 1.22 g / mL, and 88 g of this solution corresponds to a volume of 72.1 mL, containing 0.577 mol of NaOH, i.e., 0.577 mol of OH⁻. Based on D-adenosine (0.328 mol), the amount of OH⁻ used is 1.76 equivalents. In this example, with 1.76 equivalents and a residence time of 14 min, the yield is 91.9%, the purity is 99.2%, and the maximum single impurity is 0.31%.

[0036] Example 3: 100 g of D-adenosine (0.328 mmol) dissolved in 100 mL of DMF and 100 mL of pyridine (volume ratio 1:1, D-adenosine concentration 0.5 mol / L) was pumped to mixer 1 via line A using a metering pump. Trimethylchlorosilane (146 g) was pumped to mixer 1 via line B (mixer 1 was placed in a cryogenic well at 2.8°C). After mixing, the mixture was held for 9 minutes. Then, the mixture was pumped to mixer 2, while benzoyl chloride (62 g) was pumped to mixer 2 via line C (mixer 2 was placed in circulating cooling water at 12°C). After mixing, the mixture was held for 13 minutes. Then, the mixture was pumped to mixer 3, while 6N sodium hydroxide solution (102 g) was pumped to mixer 3 via line D (mixer 3 was placed in a cryogenic well at 0°C). The mixture was held at −5°C for 12 minutes.

[0037] The 6N sodium hydroxide solution has a density of 1.06 g / mL, and 102 g of this solution corresponds to a volume of 96.2 mL, containing 0.577 mol of NaOH, i.e., 0.577 mol of OH⁻. Based on D-adenosine (0.328 mol), the amount of OH⁻ used is 1.76 equivalents. This example achieves efficient conversion at 1.76 equivalents, with a yield of 88.9%, purity of 99.75%, and a maximum single impurity of 0.08%.

[0038] Comparative Example 1: 100 mL of DMF and 100 mL of D-adenosine dissolved in pyridine (100 g) were added to a reactor. The temperature was lowered to 0℃~5℃, and trimethylchlorosilane (146 g) was slowly added dropwise. The addition process was exothermic. After the addition was completed, the reaction continued for 6~8 hours. Benzoyl chloride (79 g) was added dropwise. After the addition was completed, the reaction continued for 3~4 hours. The temperature was lowered to −5℃~0℃, and 200 mL of purified water was added dropwise. 10N sodium hydroxide solution was added dropwise until pH = 7. 400 mL of acetonitrile was added, and crystallization was carried out for 2 hours. The product was filtered and dried to obtain the product with a yield of 79.1%, a purity of 87.0%, and a benzoyl impurity of 1.8%.

[0039] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-throughput microchannel continuous synthesis method for N 6 The method for benzoyl-D-adenosine, characterized in that... Includes the following steps: S1: Preparation materials: Dissolve D-adenosine in a mixed solvent of DMF and pyridine to obtain solution A; trimethylchlorosilane is solution B; benzoyl chloride is solution C; 6N~10N sodium hydroxide solution is solution D; hydrochloric acid is solution E; S2: First microchannel reaction: Liquid A and liquid B are simultaneously introduced into the first microchannel at 0℃~10℃ via a metering pump and remain for 3min~10min to complete the trimethylsilyl protection of D-adenosine hydroxyl groups; S3: Second microchannel reaction: The reaction solution obtained in step (2) and liquid C are introduced into the second microchannel at 5℃~20℃ and left for 5min~15min to complete the N 6 Selective benzoylation; S4: Third microchannel reaction: The reaction solution obtained in step (3) and liquid D enter the third microchannel at −5℃~10℃ and stay for 5min~12min, simultaneously realizing the removal of silicon and selective hydrolysis of dibenzoyl byproducts into monobenzoyl target product; S5: Post-processing: The reaction solution obtained in step (4) is adjusted to pH 6.5-7.0 with liquid E, cooled to 0℃-5℃ to crystallize, and then centrifuged and dried to obtain N. 6 -benzoyl-D-adenosine.

2. The method according to claim 1, characterized in that, The molar ratio of D-adenosine, trimethylchlorosilane and benzoyl chloride is 1:3.2-4.0:1.4-1.

6.

3. The method according to claim 1, characterized in that, The reaction temperature of the first microchannel is 2℃~5℃, and the residence time is 3min~9min.

4. The method according to claim 1, characterized in that, The reaction temperature of the second microchannel is 12℃~18℃, and the residence time is 5min~13min.

5. The method according to claim 1, characterized in that, The reaction temperature of the third microchannel is -3℃ to 5℃, and the residence time is 5 min to 12 min.

6. The method according to claim 1, characterized in that, In step (5), the crystallization is achieved by adding a mixed solvent of purified water and acetonitrile to the neutralized reaction solution, wherein the amount of purified water is 0.5 to 1.0 times the volume of the reaction solution, and the amount of acetonitrile is 1.5 to 2.5 times the volume of the reaction solution.

7. The method according to claim 1, characterized in that, The drying in step (5) is vacuum drying at 40℃~45℃ until the product moisture content is ≤1.0%.

8. The method according to claim 1, characterized in that, The microchannel system consists of three microchannels connected in series, used sequentially for silicon-based protection, N... 6 - Benzoylation, desilication and selective debenzoylation reactions; the microchannel material is selected from glass, silicon carbide or 316L stainless steel lined with PTFE.

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