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Method for preparing N-acetyl-beta-chlorine-L-alanine methyl ester

A technology of alanine methyl ester and acetyl, which is applied in the field of preparation of ramipril intermediates, can solve the problems of low reaction yield, many by-products, environmental pollution by tail gas, etc., and achieves low cost, few by-products, and high reaction yield. high rate effect

Active Publication Date: 2014-08-27
ZHEJIANG JIAHUA CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The present invention proposes a preparation method of N-acetyl-β-chloro-L-alanine methyl ester, which solves the technical problems of low reaction yield and many by-products in the prior art
[0005] The invention further solves the technical problems in the prior art that the by-products are not easy to recover and the tail gas pollutes the environment

Method used

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  • Method for preparing N-acetyl-beta-chlorine-L-alanine methyl ester
  • Method for preparing N-acetyl-beta-chlorine-L-alanine methyl ester
  • Method for preparing N-acetyl-beta-chlorine-L-alanine methyl ester

Examples

Experimental program
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Effect test

Embodiment 1

[0037] (1) Pump 300 kg of methanol into the reaction pot, start adding 90 kg of thionyl chloride dropwise, and control the temperature of the material in the pot not to exceed 20°C. After the dropwise addition, 65 kg of serine was added to the reaction pot, heated and refluxed for 10 hours, and the tail gas generated by the reaction was absorbed with 30% sodium hydroxide solution. After the reflux reaction was completed, the reaction solution was concentrated under reduced pressure to about 200 kg, lowered to normal temperature, and centrifugally filtered. Dry the precipitate at 60°C. The filtrate is concentrated, and the concentrated semi-solid is used as the masterbatch for the next batch of reaction in this step, and the distilled liquid is neutralized and separated by sodium hydroxide and reused as methanol.

[0038] (2) Pump 500 kg of dichloroethane into the reaction pot, add the above-mentioned precipitation drying material, and then pump in 60 kg of thionyl chloride an...

Embodiment 2

[0041] (1) Pump 1,500 kg of methanol into the reaction pot, start adding 450 kg of thionyl chloride dropwise, and control the temperature of the material in the pot to not exceed 20°C. After the dropwise addition, 325 kg of serine was added to the reaction pot, heated and refluxed for 15 hours, and the tail gas produced by the reaction was absorbed with 30% potassium hydroxide solution. After the reflux reaction was completed, the reaction solution was concentrated under reduced pressure to about 1000 kg, cooled to room temperature, and centrifugally filtered. Dry the precipitate at 60°C. The filtrate is concentrated, and the concentrated semi-solid is used as the masterbatch for the next batch of reaction in this step, and the distilled liquid is neutralized and separated by sodium hydroxide and reused as methanol.

[0042] (2) Pump 2,500 kg of dichloroethane into the reaction pot, add the precipitating drying material, and then pump in 300 kg of thionyl chloride and 0.03 kg...

Embodiment 3

[0045] (1) Pump 3,000 kg of methanol into the reaction pot, start to add 900 kg of thionyl chloride dropwise, and control the temperature of the material in the pot to not exceed 20°C. After the dropwise addition, 650 kg of serine was added to the reaction pot, heated and refluxed for 10 hours, and the tail gas generated by the reaction was absorbed with 30% sodium hydroxide solution. After the reflux reaction was completed, the reaction solution was concentrated under reduced pressure to about 2000 kg, cooled to room temperature, and centrifugally filtered. Dry the precipitate at 60°C. The filtrate is concentrated, and the concentrated semi-solid is used as the masterbatch for the next batch of reaction in this step, and the distilled liquid is neutralized and separated by sodium hydroxide and reused as methanol.

[0046] (2) Pump 5,000 kg of dichloroethane into the reaction pot, add the precipitating dry material, and then pump in 600 kg of thionyl chloride and 60 kg of dim...

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Abstract

The invention provides a method for preparing N-acetyl-beta-chlorine-L-alanine methyl ester. The method includes the steps that (a) serine serves as a starting material and is esterified through methanol or ethyl alcohol, (b) the esterified matter is chlorinated through sulfoxide chloride, (c) the chlorinated matter undergoes acylation, (d) the acylated matter is recrystallized, and accordingly the N-acetyl-beta-chlorine-L-alanine methyl ester is obtained. The method is high in reaction yield, by-products are few, reaction mother liquor is recycled and reused, distilled liquid obtained after acylation is acetic acid and acetic anhydride, and the liquid is recycled and reused after being purified. Accordingly, cost is low, tail gas generated in reactions is absorbed through strong-base solutions to form salt and then is separated and used, and accordingly environment protection is achieved.

Description

technical field [0001] The invention relates to the technical field of preparation of ramipril intermediates, in particular to a preparation method of N-acetyl-β-chloro-L-alanine methyl ester. Background technique [0002] Ramipril is an antihypertensive drug, which is hydrolyzed in the liver after being absorbed from the gastrointestinal tract into an active angiotensin-converting enzyme (ACE) inhibitor - ramiprilat. It has a good curative effect on severe hypertensive patients. Because it can increase renal blood flow and reduce renal vascular resistance, it is also suitable for patients with renal damage or diabetes. It has the advantages of quick onset, long duration, high tissue specificity, good tolerance, and low toxic and side effects. [0003] N-acetyl-β-chloro-L-alanine methyl ester is an important intermediate of ramipril. There are many ways to synthesize it, but all of them have the problems of low yield, many by-products and difficult recovery. Difficulty i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C231/02C07C233/47
Inventor 施自恩
Owner ZHEJIANG JIAHUA CHEM
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