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Method for synthesizing (R,S)1-bromoethyl acetate

A technology of ethyl acetate and bromination, applied in the field of cefuroxime axetil key intermediate (R field, can solve the problems of increasing the amount of acidic waste water, increasing the three wastes, complicated operations, etc., reducing the discharge of the three wastes, facilitating control, Simple to use effects

Active Publication Date: 2012-04-18
ZHEJIANG GUOBANG PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0011] Solvent needs to be recovered, the operation is cumbersome, the yield is low ≤ 70%, the content is low ≤ 85%, the cost is high, and the introduction of acetic acid increases the amount of acidic wastewater and the three wastes

Method used

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  • Method for synthesizing (R,S)1-bromoethyl acetate
  • Method for synthesizing (R,S)1-bromoethyl acetate

Examples

Experimental program
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Embodiment 1

[0031] Add 45 ml of N,N-dimethylacetamide to a 250 ml four-necked flask equipped with a stirrer and a thermometer, cool to -17~-15°C, add 10.4 ml (0.185 mol) of acetaldehyde while stirring. Add 0.3g (0.002 mol) of 1-tetralone, cool the temperature of the material to -20~-18°C, and slowly drop in 21.94g (0.178 mol) of acetyl bromide. Control the temperature at 4-6°C and fully stir the reaction for 7 hours. The gas phase content is 94.16%, and the α-bromine impurity content is 0.76%. The molar yield is 89.65%.

Embodiment 2

[0033] Add 45 ml of acetonitrile to a 250 ml four-necked flask equipped with a stirrer and a thermometer, cool to -17~-15°C, add 10.4 ml (0.185 mol) of acetaldehyde while stirring and keeping warm. Add 0.1g (0.00068 mol) of 1-tetralone, cool the temperature of the material to -20~-18°C, and slowly drop in 21.94g (0.178 mol) of acetyl bromide. Control the temperature at -10°C and fully stir the reaction for 12 hours. The gas phase content is 94.34%, and the α-bromine impurity content is 0.11%. The molar yield is 75.71%.

Embodiment 3

[0035] Add 45 ml of dimethyl sulfoxide to a 250 ml four-necked flask equipped with a stirrer and a thermometer, cool to -17~-15°C, add 10.4 ml (0.185 mol) of acetaldehyde while stirring. Add 0.026g (0.000178 mol) of 1-tetralone, cool the temperature of the material to -20~-18°C, and slowly drop in 21.94g (0.178 mol) of acetyl bromide. The temperature was controlled at 25°C and the reaction was sufficiently stirred for 2 hours. The gas phase content is 85.98%, and the α-bromine impurity content is 3.51%. The molar yield is 78.49%.

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Abstract

The invention relates to a method for synthesizing (R,S)1-bromoethyl acetate. The method comprises the following steps of: dissolving acetaldehyde and acetyl bromide into a solvent, and reacting in the presence of a catalyst with a naphthalene ring structure to obtain the (R,S)1-bromoethyl acetate. By the method, the content and yield of the (R,S)1-bromoethyl acetate are remarkably improved; the process is simple and can be operated stably; three wastes (waste gas, waster water and industrial residues) are reduced; the cost is reduced; the content and yield of cefuroxime axetil are remarkably improved when the method is applied to the production; and the method is suitable for industrialized production.

Description

technical field [0001] The invention relates to a preparation method of (R, S) 1-bromoethyl acetate, a key intermediate of cefuroxime axetil, and belongs to the technical field of preparation of cephalosporin drug intermediates and other compounds. Background technique [0002] (R, S) 1-Bromoethyl acetate is an important intermediate in the synthesis of cephalosporin drug - cefuroxime axetil. Because the raw materials used and its own properties are quite active, it is easy to be destroyed and the preparation is high. The content of (R, S) 1-bromoethyl acetate is more difficult, which greatly affects the quality and process stability of cefuroxime axetil. Its main synthetic routes are: [0003] 1. Using zinc chloride as a catalyst, it is prepared by reacting acetyl bromide with paraldehyde, then extracting with dichloromethane, washing with water, and recovering the dichloromethane to dryness under reduced pressure. (EP9993727) [0004] [0005] The above-mentioned rou...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C69/63C07C67/287
Inventor 邱家军张宜仲侯仲轲王宗利施颖峰潘伯安肖秋霞
Owner ZHEJIANG GUOBANG PHARMA
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