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Preparation process of L-methyldopa methyl ester

A technology of methyl dopa methyl ester and preparation process, which is applied in the preparation of organic compounds, cyanide reaction preparation, organic chemistry and other directions, can solve the problems of difficult environmental protection, reduced product quality and yield, and high reaction temperature, and achieves The effect of easy industrial production, less side reactions and cost reduction

Inactive Publication Date: 2018-06-12
SHANDONG XINHUA PHARMA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This kind of preparation technology, existing problems are: reaction temperature is high, energy consumption is high; Recycling solvent cost is high, and the water content of reclaiming solvent is high, if reclaiming solvent mechanically, the solvent of reclaiming is methanol or ethanol that evaporates, and wherein water will It affects the progress of the esterification reaction, the reaction is not complete, and the product quality and yield are greatly reduced. Therefore, the recovery solvent cannot be used mechanically, and a large amount of acidic industrial wastewater will be generated. It is difficult to deal with environmental protection and high cost, so it is not suitable for industrial production.

Method used

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  • Preparation process of L-methyldopa methyl ester
  • Preparation process of L-methyldopa methyl ester
  • Preparation process of L-methyldopa methyl ester

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] In the reaction flask, add 240g of L-methyldopa and 1440g of methanol, stir, control the temperature at 4°C, pass 1440g of HCl gas, and keep the temperature at 20°C for 72h after passing through. After the reaction, the reaction liquid was centrifuged, and the speed of the centrifuge was controlled to 1200r / min, and the centrifuged mother liquor was used for recycling, and at the same time, the centrifuged material was transferred to another reaction bottle, 560g of purified water was added, and stirred and dissolved at 50°C for 2h. After dissolving and clarifying, adjust the pH value with 20 wt.% ammonia water, keep the temperature at 40° C., and adjust the pH value to 6. After neutralization, lower the temperature to 5 °C, stir for 1 h, control the centrifuge speed at 1500 r / min, centrifuge, wash, and dry at 50 °C for 12 h to obtain L-methyldopa methyl ester with a yield of 70.3%. The analysis and detection carried out the content detection, and the content was 99.5%....

Embodiment 2

[0034] In the reaction tank, add the methanol mother liquor filtered in Example 1, 24g of methanol and 240g of L-methyldopa, stir, control the temperature at 15°C and feed 24g of HCl gas, and keep the temperature at 30°C for 72h after passing through. After the reaction, centrifuge the reaction solution, control the speed of the centrifuge to 1200r / min, centrifuge the mother liquor for recycling, and transfer the centrifuged material to another reaction tank, add 560g of purified water, stir and dissolve at 70°C for 0.5h . After dissolving and clarifying, adjust the pH value with 30% sodium hydroxide, keep the temperature at 45° C. when adjusting the pH value, and adjust the pH=8. After neutralization, lower the temperature to 15°C, stir for 1 hour, control the speed of the centrifuge to 1500r / min, centrifuge, wash, and dry at 70°C for 6 hours to obtain L-methyldopa methyl ester with a yield of 67.3%. The analysis and detection carried out the content detection, and the conte...

Embodiment 3

[0036] In the reaction tank, add the methanol mother liquor filtered in Example 1, 24g of methanol and 240g of L-methyldopa, stir, control the temperature at 40°C and feed 24g of HCl gas, and keep the temperature at 30°C for 48h after passing through. . After the reaction, centrifuge the reaction liquid, control the speed of the centrifuge to 1200r / min, centrifuge the mother liquor for recycling, and transfer the centrifuged material to another reaction tank, add 560g of purified water, stir and dissolve at 50°C for 1h. After dissolving and clarifying, adjust the pH value with 10% sodium carbonate, keep the temperature at 50° C. when adjusting the pH value, and adjust the pH=7. After neutralization, lower the temperature to 8 °C, stir for 1 h, control the centrifuge speed at 1500 r / min, centrifuge, wash, and dry at 55 °C for 10 h to obtain L-methyldopa methyl ester with a yield of 71.7%. The analysis and detection carried out the content detection, and the content was 99.4%.

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Abstract

The invention relates to a preparation process of L-methyldopa methyl ester and belongs to the field of organic chemical synthesis. The preparation process of the L-methyldopa methyl ester comprises the following steps of 1, sequentially adding L-methyldopa and methanol and introducing hydrogen chloride; 2, at 0-45 DEG C, performing esterification reaction for 10-72 H; 3, after esterification reaction is completed, performing filtering, dissolution, neutralization, crystallization, centrifugation and drying to obtain a finished product. The preparation process of the L-methyldopa methyl estercan provide increased yield and reduced energy consumption, and meanwhile, through circulated application of a mother solution, the cost can be reduced and good environment friendliness can be provided.

Description

technical field [0001] The invention relates to a preparation process of L-methyldopa methyl ester, which belongs to the field of organic chemical synthesis. Background technique [0002] L-methyldopa methyl ester is an important intermediate in the carbidopa preparation process, and the technology of preparing L-methyldopa methyl ester with L-methyldopa as raw material is basically all according to literature at present: 1. Cui Jianguo, Feng Rui, Li Ruohua, etc. Synthesis of Carbidopa from Natural Levodopa[J]. Fine Chemical Industry, 2007, 24(4):387-391. [0003] [0004] 2. Li Jianjun, Sun Xiuling, Jiang Lingbo, etc.; A new synthesis process of L-α-(3,4-dimethoxybenzyl)-α-ureidopropionic acid [J]. Journal of Chemical Engineering of Universities, 2008, 22(4 ):650-654. [0005] [0006] In Documents 1 and 2, after the raw material L-methyldopa is dissolved in methanol or ethanol, HCl gas is introduced, then the temperature is raised to 60-70° C., and the reaction is ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C227/18C07C229/36
CPCC07B2200/07C07C227/18C07C229/36
Inventor 王兵沈平阎培军王宜运孔青范春伟王锡春王智
Owner SHANDONG XINHUA PHARMA CO LTD
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