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Method for preparing ortho-chloromandelic acid

A technology of o-chloromandelic acid and sodium mandelate, which is applied in the field of organic synthesis, can solve the problems of increasing labor intensity and high price, and achieve the effects of reducing labor intensity, reducing production costs, and high purity

Inactive Publication Date: 2005-10-26
EAST CHINA UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this method avoids hydrocyanic acid, it uses bromoform, which is very expensive and infrequently used, and the crude product must be taken out first, which increases the labor intensity

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] In a 1000ml three-necked flask, add 100ml (0.887mol) of o-chlorobenzaldehyde, 160ml (1.87mol) of chloroform and 10g (0.044mol) of triethylbenzyl ammonium chloride (TEBA) powder, and heat up to 60°C. Slowly add 250ml of 50% sodium hydroxide solution prepared in advance dropwise under stirring at high temperature. After the dropwise addition, keep warm for 1 hour, add 500ml of water to dilute and cool the reaction solution to room temperature, and separate the lower layer of chloroform. Use 3mol / L hydrochloric acid solution to adjust the pH of the solution to 1, add 250ml of ethyl acetate for extraction, separate the water phase and ethyl acetate, and then extract the water phase twice with 120ml and 60ml of ethyl acetate respectively, combine the three extractions of ethyl acetate, and subtract Concentrate under reduced pressure to remove 400 ml of ethyl acetate to obtain crude o-chloromandelic acid in the form of yellow oil.

Embodiment 2

[0028] Add 40g of solid sodium hydroxide, 200ml of water, and 80ml of toluene to the yellow oily o-chloromandelic acid crude product remaining in Example 1, heat to 80°C, keep warm for 1 hour, cool, separate the water phase, and then use 3mol / L hydrochloric acid for the water phase Adjust the pH of the solution to 1, add 250ml of ethyl acetate for extraction, separate the water phase and ethyl acetate, and then extract the water phase with 120ml and 60ml of ethyl acetate, respectively, and combine three extractions of ethyl acetate. After the ethyl acetate was removed by evaporation under reduced pressure, 250ml of toluene was added, stirred and cooled to room temperature, and a little o-chloromandelic acid crystal was added as a seed crystal, the precipitated crystal was filtered by suction, and dried to obtain 91.5g of a white crystalline product. Yield 55.3%, mp: 87.0°C to 88.5°C.

Embodiment 3

[0030] In a 250ml three-necked flask, add 20ml (0.177mol) of o-chlorobenzaldehyde, 32ml (0.38mol) of chloroform and 2g (0.009mol) of triethylbenzyl ammonium chloride (TEBA), and raise the temperature to 60°C. Slowly add 50ml of 50% sodium hydroxide solution prepared in advance dropwise under stirring, and the rest is according to the method in Example 1 to obtain the crude product of yellow oily o-chloromandelic acid, add 250ml of toluene to the remaining yellow oil, and filter with suction to obtain Yellow sticky solid, after drying, 16.3g was obtained, mp<80°C, the solid was recrystallized with 30ml of toluene to obtain 14.5g of a yellowish refined product, the total yield in two steps was 43.9%, mp: 82.5°C-84.5°C.

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PUM

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Abstract

The present invention relates to an improved preparation method of ortho-chloro-mandelic acid. Said method uses ortho-chlorobenzaldehyde and chloroform as raw material, and adopts the following steps: under the action of concentrated alkali and phase-transfer catalyst making the raw materials fully react, using ethyl acetate to make extraction, then removing ethyl acetate, adding alkali and water, using toluene to extract and remove impurities from aqueous solution of sodium ortho-chloromandelate, making acidification, using ethyl acetate to make extraction and using toluene to make crystallization, so that adopting one-kettle process to prepare ortho-chloromandelic acid.

Description

technical field [0001] The invention belongs to the field of organic synthesis, in particular, the invention relates to an improved method for preparing o-chloromandelic acid. Background technique [0002] O-chloromandelic acid, also known as α-hydroxyphenylacetic acid (2-chloromandelic acid), molecular formula C 8 h 7 o 3 Cl, the molecular weight is 186.5. Among them, R-o-chloromandelic acid is used to synthesize the new drug Clapidol (clopidogrel), which is the most effective drug for preventing angina pectoris and stroke in the West, ranking 10th in the global drug sales list in 2000. [0003] The preparation method of o-chloromandelic acid has been reported in the document "Journal of American Chemical Society" (J Am Chem Soc) S.S.Jenking1931.53.2341, is that o-chlorobenzaldehyde and hydrocyanic acid are reacted to generate o-chloromandelonitrile, and then o-chloromandelonitrile is Mandelonitrile is hydrolyzed to produce o-chloromandelic acid. This method uses highl...

Claims

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Application Information

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IPC IPC(8): C07C59/56
Inventor 彭阳峰赵红亮蔡水洪
Owner EAST CHINA UNIV OF SCI & TECH
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