Preparation method of N-carbonyl benzyloxy-L-lysine
By using quaternary ammonium salt-ethylene glycol borate-based polystyrene as complexing reagent, the problems of more copper ion wastewater and more 9-BBN by-products in the prior art were solved, and efficient and environmentally friendly preparation of N-carbonylbenzyloxy-L-lysine was achieved, which has good industrial application value.
Patent Information
- Application Number
- CN202510227432.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-27
- Publication Date
- 2025-06-06
AI Technical Summary
In the prior art, copper ions are as complexing reagents, and copper ions have a large number of by-products as complexing reagents, which affects environmental protection and industrial applications.
Quaternary ammonium salt-ethylene glycol borate-based polystyrene was used as complexing reagent, and N-lysine hydrochloride was reacted under the action of phosphate buffer and N,N-dimethylformamide to protect the α-amino and carboxylic groups, and then the ε-amino was functionalized to benzyloxycarbonyl, and finally deborate protection was used to obtain N-carbonylbenzyloxy-L-lysine.
The formation of copper ion wastewater and by-products is avoided, with high selectivity, mild reaction conditions, and complexing reagents that are recyclable and recyclable, are environmentally friendly and have good industrial application value.
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Figure CN120097870A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of organic synthesis, and specifically relates to a method for preparing N-carbonylbenzyloxy-L-lysine. Background Art
[0002] Lysine is one of the essential amino acids that cannot be synthesized by the human body and animals. It is widely used in the food industry, feed industry, pharmaceutical industry and chemical industry.
[0003] Lysine is used as a pharmaceutical chemical intermediate or raw material, and usually needs to be protected by the ε-amino group. Currently, the most common method for protecting lysine is to use copper ions to simultaneously protect the α-amino group and the carboxyl group, then use benzyloxycarbonyl to protect the ε-amino group, and finally remove the complexed copper ions to obtain N-carbonylbenzyloxy-L-lysine. This method has the problems of long protection time, incomplete reaction, and a lot of copper ion wastewater. Using 9-boranobicyclo[3.3.1]nonane (9-BBN) as a complexing agent will result in a large amount of water and by-products, which is not environmentally friendly. Summary of the invention
[0004] The purpose of the present invention is to provide a method for preparing N-carbonylbenzyloxy-L-lysine to solve the technical problems that copper ions used as complexing agents produce a lot of copper ion wastewater and 9-BBN used as complexing agents produces a large amount of by-products.
[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is:
[0006] A method for preparing N-carbonylbenzyloxy-L-lysine comprises the following steps:
[0007] S1: L-lysine hydrochloride is mixed with a boron-containing complexing agent, and reacted in a phosphate buffer and N,N-dimethylformamide to obtain an intermediate b, as shown in Formula I;
[0008]
[0009] S2: The intermediate b is mixed with a benzyloxycarbonyl compound, and reacted under the action of a base and a solvent to obtain an intermediate c, and the reaction formula is shown in Formula II;
[0010]
[0011] S3: After the intermediate c is mixed with phosphate buffer, it reacts under the action of N,N-dimethylformamide to obtain N-carbonylbenzyloxy-L-lysine. The reaction formula is shown in Formula III:
[0012]
[0013] Furthermore, the pH of the phosphate buffer in S1 and S3 is 7.4, the phosphate buffer comprises potassium dihydrogen phosphate and disodium hydrogen phosphate, and the boron-containing complexing agent is quaternary ammonium salt-ethylene glycol borate-based polystyrene.
[0014] Furthermore, the structure of the boron-containing complexing agent is shown in Formula IV;
[0015]
[0016] Furthermore, the mass ratio of L-lysine hydrochloride to the boron-containing complexing agent in S1 is 1:2.04-3.06; the mass ratio of L-lysine hydrochloride to N,N-dimethylformamide is 1:2-10; and the volume ratio of the phosphate buffer to N,N-dimethylformamide is 1:3.
[0017] Furthermore, the reaction temperature in S1 is 25-40° C., and the reaction time is 0.5-1.5 h.
[0018] Furthermore, in S2, the mass ratio of the intermediate b to the benzyloxycarbonyl compound is 1:0.34-0.9; the mass ratio of the intermediate b to the base is 1:0.15-0.4; and the mass ratio of the intermediate b to the solvent is 1:2-10.
[0019] Furthermore, the reaction temperature in S2 is 0-30° C., and the reaction time is 2-5 h.
[0020] Furthermore, the benzyloxycarbonyl compound in S2 is one or more of benzyl chloroformate and benzyloxycarbonyl succinimide; the base is one or more of sodium bicarbonate, potassium bicarbonate, and triethylamine; and the solvent is one or more of N-methylpyrrolidone, water, tetrahydrofuran, dimethyl sulfoxide, and N,N-dimethylformamide.
[0021] Furthermore, the mass ratio of the intermediate c to N,N-dimethylformamide in S3 is 1:2-10; the volume ratio of N,N-dimethylformamide to phosphate buffer is 1:3; the reaction temperature in S3 is 25-40°C, and the reaction time is 0.5-1.5h.
[0022] Beneficial effects of the present invention:
[0023] The complexing agent of the invention selects a quaternary ammonium salt-ethylene glycol borate-based polystyrene complexing agent. The use of the quaternary ammonium salt-ethylene glycol borate-based polystyrene complexing agent avoids copper ions and 9-BBN generated by waste water with a large amount of copper ions, and the quaternary ammonium salt-ethylene glycol borate-based polystyrene complexing agent can be recycled and reused, and is environmentally friendly; the reaction selectivity is high, and the generation of by-products is avoided; the reaction is carried out at room temperature, the conditions are mild, the operation is simple, the reaction is more economical and green, and the requirements of large-scale industrial production are met, and the reaction has good industrial application value.
[0024] The invention uses L-lysine hydrochloride and a boron-containing complexing agent to protect the α-amino group and the carboxyl group, then performs benzyloxycarbonyl functionalization on the ε-amino group, and finally deborates the protection to obtain N-carbonylbenzyloxy-L-lysine. The invention has high selectivity, mild reaction conditions, and the complexing agent can be recycled and reused, is environmentally friendly, and has good industrial application value. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 It is the high performance liquid chromatogram of N-carbonylbenzyloxy-L-lysine in Example 1. DETAILED DESCRIPTION
[0026] The present invention will be further described below in conjunction with the embodiments of the present invention and the accompanying drawings.
[0027] The preparation method of quaternary ammonium salt-ethylene glycol borate polystyrene (QB) is synthesized according to a known method:
[0028] Under nitrogen atmosphere, 3-dimethylamino-1,2-propanediol and boric acid were added to a reaction bottle with an oil-water separator in a molar ratio of 1:1.26, and then toluene was added as a water-carrying agent and solvent. The reaction was stopped by reflux reaction until no water was separated from the water separator. Toluene was evaporated by rotary evaporator under reduced pressure to obtain a yellow transparent borate solid. The obtained borate solid was dissolved in acetone, and 4-chloromethylstyrene was added dropwise at room temperature, and the reflux reaction was continued for 3 hours. After the reaction was cooled to room temperature, anhydrous sodium carbonate was added for neutralization, and then a large amount of dichloromethane was used to dissolve it. After rotary evaporation, a yellow product was obtained, and the obtained yellow product was precipitated in petroleum ether 3 times. Finally, it was vacuum dried at room temperature for 3 hours to obtain a yellow powder, i.e., quaternary ammonium salt-ethylene glycol borate ester styrene.
[0029] 2.4 g and 8.6 mmol of quaternary ammonium salt-ethylene glycol borate ester styrene was used as a monomer, azobisisobutyronitrile was used as an initiator, and N,N-dimethylformamide / water (v / v, 1 / 3) was used as a mixed solvent, and the reaction was carried out under vacuum at 70°C for 24 hours. The reaction solution was transferred to a dialysis bag with a molecular weight cutoff of 3500, and dialyzed with ultrapure water for 3 days. Finally, the liquid in the dialysis bag was freeze-dried to obtain polystyrene quaternary ammonium salt-ethylene glycol borate, and the polystyrene quaternary ammonium salt-ethylene glycol borate was dissolved in pure water to obtain a polystyrene quaternary ammonium salt-ethylene glycol borate solution, and the polystyrene quaternary ammonium salt-ethylene glycol borate solution was titrated with hydrobromic acid at room temperature until the pH of the polystyrene quaternary ammonium salt-ethylene glycol borate solution was 0.5 to obtain QB.
[0030] Phosphate buffer (NaPB): Dissolve 136.89 g sodium chloride, 6.8 g potassium chloride, 17.55 g disodium hydrogen phosphate, and 2.4 g potassium dihydrogen phosphate in distilled water and adjust the pH of the solution to 7.4 with hydrochloric acid.
[0031] Example 1
[0032] The preparation method of N-carbonylbenzyloxy-L-lysine of Example 1 comprises the following steps:
[0033] 37.2 g of QB was dissolved in 38.4 mL of N,N-dimethylformamide (DMF) to obtain solution 1, and 18.2 g of L-lysine hydrochloride was dissolved in 12.8 mL of phosphate buffer with a concentration of 0.1 M and a pH of 7.4 to obtain solution 2; solution 1 was added to solution 2 at room temperature, and stirred at 25°C for 1.5 h to obtain a mixed solution; the mixed solution was poured into water and extracted three times with ethyl acetate, and the single amount of ethyl acetate used was 50 mL. The organic layer was washed with brine, dried with anhydrous sodium sulfate, and eluted with methanol-water (3:1) for column chromatography to obtain 45.5 g of intermediate b, with a yield of 91%.
[0034] 45.5 g of intermediate b, 6.8 g of sodium bicarbonate, and 91 mL of tetrahydrofuran (THF) were mixed to obtain a mixture, and 15.5 g of benzyl chloroformate was poured into the stirred mixture at 0°C, monitored by thin layer chromatography (TLC), stirred at 0°C for 5 h, and then extracted three times with dichloromethane, with a single amount of 50 mL. The organic phase was dried and evaporated to obtain a solid, which was eluted with hexane-ethyl acetate (2:1) by column chromatography to obtain 54.8 g of intermediate c, with a yield of 95%.
[0035] Dissolve 54.8g of intermediate c in 115.6mL of DMF, and add 346.8mL of 0.1M phosphate buffer at pH 7.4 at room temperature. After stirring at 40°C for 0.5h, pour into water and filter, recover QB from the filter cake, and extract the filtrate three times with ethyl acetate, with a single usage of 100mL. Wash the organic layer with brine, dry with anhydrous sodium sulfate, and elute with methanol-water (3:1) for column chromatography to obtain 23.4g of N-carbonylbenzyloxy-L-lysine with a purity of 99.98% and a yield of 96.7%.
[0036] The reaction pathway of N-carbonylbenzyloxy-L-lysine in Example 1 is shown in Formula V:
[0037]
[0038] Example 2
[0039] The preparation method of N-carbonylbenzyloxy-L-lysine of Example 2 comprises the following steps:
[0040] 45.5 g of QB was dissolved in 91 mL of DMF to obtain solution 1, and 18.2 g of L-lysine hydrochloride was dissolved in 30.3 mL of phosphate buffer with a concentration of 0.1 M and a pH of 7.4 to obtain solution 2; solution 1 was added to solution 2 at room temperature, and stirred at 35°C for 1 h to obtain a mixed solution; the mixed solution was poured into water and extracted three times with ethyl acetate, with a single amount of 100 mL of ethyl acetate. The organic layer was washed with brine, dried with anhydrous sodium sulfate, and eluted with methanol-water (3:1) for column chromatography to obtain 46.1 g of intermediate b with a yield of 92.3%.
[0041] 46.1 g of intermediate b, 13.8 g of sodium bicarbonate, and 230 mL of THF were mixed to obtain a mixture, and 18.4 g of benzyl chloroformate was poured into the stirred mixture at 0°C, monitored by TLC, stirred at 10°C for 3 h, and then extracted three times with dichloromethane, with a single amount of 50 mL. The organic phase was dried and evaporated to obtain a solid, which was eluted with hexane-ethyl acetate (2:1) by column chromatography to obtain 55.1 g of intermediate c, with a yield of 94.3%.
[0042] Dissolve 55.1g of intermediate c in 275mL of DMF, and add 825mL of 0.1M phosphate buffer at pH 7.4 at room temperature. Stir at 30°C for 1h, pour into water and filter, recover QB from the filter cake, and extract the filtrate three times with ethyl acetate, with a single usage of 100mL. Wash the organic layer with brine, dry with anhydrous sodium sulfate, and elute with methanol-water (3:1) for column chromatography to obtain 23.6g of N-carbonylbenzyloxy-L-lysine with a purity of 99.4% and a yield of 97%.
[0043] Example 3
[0044] The preparation method of N-carbonylbenzyloxy-L-lysine of Example 3 comprises the following steps:
[0045] 54.6 g of QB was dissolved in 182 mL of DMF to obtain solution 1, and 18.2 g of L-lysine hydrochloride was dissolved in 60.7 mL of phosphate buffer with a concentration of 0.1 M and a pH of 7.4 to obtain solution 2; solution 1 was added to solution 2 at room temperature, and stirred at 40°C for 0.5 h to obtain a mixed solution; the mixed solution was poured into water and extracted three times with ethyl acetate, with a single amount of 50 mL of ethyl acetate. The organic layer was washed with brine, dried with anhydrous sodium sulfate, and eluted with methanol-water (3:1) for column chromatography to obtain 43.6 g of intermediate b with a yield of 87.3%.
[0046] 43.6 g of intermediate b, 6.8 g of sodium bicarbonate, and 436 mL of THF were mixed to obtain a mixture, 15.5 g of benzyl chloroformate was poured into the stirred mixture at 0°C, monitored by TLC, stirred at 30°C for 2 h, and then extracted three times with dichloromethane, with a single amount of 500 mL. The organic phase was dried and evaporated to obtain a solid, which was eluted with hexane-ethyl acetate (2:1) by column chromatography to obtain 53.6 g of intermediate c, with a yield of 96.9%.
[0047] Dissolve 53.6g of intermediate c in 536mL of DMF, and add 1608mL of 0.1M phosphate buffer at pH 7.4 at room temperature. Stir at 40°C for 0.5h, pour into water and filter, recover QB from the filter cake, and extract the filtrate three times with ethyl acetate, with a single usage of 100mL. Wash the organic layer with brine, dry with anhydrous sodium sulfate, and elute with methanol-water (3:1) for column chromatography to obtain 22.5g of N-carbonylbenzyloxy-L-lysine with a purity of 99.8% and a yield of 95%.
[0048] Example 4
[0049] The preparation method of N-carbonylbenzyloxy-L-lysine of Example 4 comprises the following steps:
[0050] 45.5 g of QB was dissolved in 38.4 mL of DMF to obtain solution 1, and 18.2 g of L-lysine hydrochloride was dissolved in 12.8 mL of phosphate buffer with a concentration of 0.1 M and a pH of 7.4 to obtain solution 2; solution 1 was added to solution 2 at room temperature, and stirred at 25°C for 1.5 h to obtain a mixed solution; the mixed solution was poured into water and extracted three times with ethyl acetate, with a single amount of 50 mL of ethyl acetate. The organic layer was washed with brine, dried with anhydrous sodium sulfate, and eluted with methanol-water (3:1) for column chromatography to obtain 47.6 g of intermediate b with a yield of 95.3%.
[0051] 47.6 g of intermediate b, 7.14 g of potassium bicarbonate, and 100 mL of N-methylpyrrolidone (NMP) were mixed to obtain a mixture, and 16.18 g of benzyl chloroformate was poured into the stirred mixture at 0°C, monitored by TLC, stirred at 0°C for 2 h, and then extracted three times with dichloromethane, with a single amount of 50 mL. The organic phase was dried and evaporated to obtain a solid, which was eluted with hexane-ethyl acetate (2:1) by column chromatography to obtain 58.5 g of intermediate c, with a yield of 97%.
[0052] Dissolve 58.5g of intermediate c in 123.4mL of DMF, and add 370.2mL of 0.1M phosphate buffer at pH 7.4 at room temperature. Stir at 40°C for 0.5h, pour into water and filter, recover QB from the filter cake, and extract the filtrate three times with ethyl acetate, with a single usage of 100mL. Wash the organic layer with brine, dry with anhydrous sodium sulfate, and elute with methanol-water (3:1) for column chromatography to obtain 24.0g of N-carbonylbenzyloxy-L-lysine with a purity of 99.5% and a yield of 93%.
[0053] Example 5
[0054] The preparation method of N-carbonylbenzyloxy-L-lysine of Example 5 comprises the following steps:
[0055] 37.2 g of QB was dissolved in 127.5 mL of DMF to obtain solution 1, and 18.2 g of L-lysine hydrochloride was dissolved in 42.5 mL of phosphate buffer with a concentration of 0.1 M and a pH of 7.4 to obtain solution 2; solution 1 was added to solution 2 at room temperature, and stirred at 25°C for 1.5 h to obtain a mixed solution; the mixed solution was poured into water and extracted three times with ethyl acetate, and the single amount of ethyl acetate used was 500 mL. The organic layer was washed with brine, dried with anhydrous sodium sulfate, and eluted with methanol-water (3:1) for column chromatography to obtain 45.2 g of intermediate b, with a yield of 90.5%.
[0056] 45.2 g of intermediate b, 6.8 g of triethylamine, and 91 mL of dimethyl sulfoxide (DMSO) were mixed to obtain a mixture, and 40.7 g of benzyloxycarbonyl succinimide was poured into the stirred mixture at 0°C, monitored by TLC, stirred at 0°C for 3 h, and then extracted three times with dichloromethane, with a single amount of 50 mL. The organic phase was dried and evaporated to obtain a solid, which was eluted with hexane-ethyl acetate (2:1) by column chromatography to obtain 53.0 g of intermediate c, with a yield of 92.5%.
[0057] 53.0 g of intermediate c was dissolved in 159 mL of DMF, and 477 mL of 0.1 M phosphate buffer at pH 7.4 was added at room temperature. After stirring at 40 ° C for 0.5 h, the mixture was poured into water and filtered, QB was recovered from the filter cake, and the filtrate was extracted three times with ethyl acetate, with a single use amount of 100 mL. The organic layer was washed with brine, dried with anhydrous sodium sulfate, and eluted with methanol-water (3:1) for column chromatography to obtain 22.3 g of N-carbonylbenzyloxy-L-lysine with a purity of 99.6% and a yield of 95%.
Claims
1. A method for preparing N-carbonylbenzyloxy-L-lysine, characterized in that: The following steps are involved: S1: L-lysine hydrochloride is mixed with a boron-containing complexing agent, and reacted in a phosphate buffer and N,N-dimethylformamide to obtain an intermediate b, as shown in Formula I; S2: The intermediate b is mixed with a benzyloxycarbonyl compound, and reacted under the action of a base and a solvent to obtain an intermediate c, and the reaction formula is shown in Formula II; S3: After the intermediate c is mixed with phosphate buffer, it reacts under the action of N,N-dimethylformamide to obtain N-carbonylbenzyloxy-L-lysine. The reaction formula is shown in Formula III:
2. The method for preparing N-carbonylbenzyloxy-L-lysine according to claim 1, characterized in that: The pH of the phosphate buffer in S1 and S3 is 7.4, the phosphate buffer comprises potassium dihydrogen phosphate and disodium hydrogen phosphate, and the boron-containing complexing agent is quaternary ammonium salt-ethylene glycol borate-based polystyrene.
3. The method for preparing N-carbonylbenzyloxy-L-lysine according to claim 1 or 2, characterized in that: The structure of the boron-containing complexing agent is shown in Formula IV; 4. The method for preparing N-carbonylbenzyloxy-L-lysine according to claim 1, characterized in that: The mass ratio of L-lysine hydrochloride to the boron-containing complexing agent in S1 is 1:2.04-3.06; the mass ratio of L-lysine hydrochloride to N,N-dimethylformamide is 1:2-10; and the volume ratio of the phosphate buffer to N,N-dimethylformamide is 1:
3.
5. The method for preparing N-carbonylbenzyloxy-L-lysine according to claim 1, characterized in that: The reaction temperature in S1 is 25-40°C, and the reaction time is 0.5-1.5h.
6. The method for preparing N-carbonylbenzyloxy-L-lysine according to claim 1, characterized in that: The mass ratio of the intermediate b to the benzyloxycarbonyl compound in S2 is 1:0.34-0.9; the mass ratio of the intermediate b to the base is 1:0.15-0.4; the mass ratio of the intermediate b to the solvent is 1:2-10.
7. The method for preparing N-carbonylbenzyloxy-L-lysine according to claim 1, characterized in that: The reaction temperature in S2 is 0-30°C, and the reaction time is 2-5h.
8. The method for preparing N-carbonylbenzyloxy-L-lysine according to claim 1, characterized in that: The benzyloxycarbonyl compound in S2 is one or more of benzyl chloroformate and benzyloxycarbonyl succinimide; the base is one or more of sodium bicarbonate, potassium bicarbonate, and triethylamine; and the solvent is one or more of N-methylpyrrolidone, water, tetrahydrofuran, dimethyl sulfoxide, and N,N-dimethylformamide.
9. The method for preparing N-carbonylbenzyloxy-L-lysine according to claim 1, characterized in that: The mass ratio of the intermediate c to N,N-dimethylformamide in S3 is 1:2-10; the volume ratio of N,N-dimethylformamide to phosphate buffer is 1:3; the reaction temperature in S3 is 25-40°C, and the reaction time is 0.5-1.5h.