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Preparation method of 2,4-dihydroxyphenyl acetic acid

A technology of dihydroxyphenylacetic acid and hydroxyphenylacetic acid, applied in the field of preparation of 2,4-dihydroxyphenylacetic acid, can solve the problems of low reaction yield, polluted environment, difficult separation and recycling of by-products, etc., and achieves the preparation route Brief, mild reaction conditions

Active Publication Date: 2016-05-04
SUN YAT SEN UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, these methods all have the disadvantages of low reaction yield, use of highly toxic sodium cyanide and benzyl nitrile, polluting the environment, and difficult separation and recycling of by-products.

Method used

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  • Preparation method of 2,4-dihydroxyphenyl acetic acid
  • Preparation method of 2,4-dihydroxyphenyl acetic acid
  • Preparation method of 2,4-dihydroxyphenyl acetic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Example 1: Synthesis of 2-bromo-4-hydroxymandelic acid

[0025] Add sodium hydroxide solution (43.2g, 1.08mol) and glyoxylic acid monohydrate aqueous solution (79.5g, 0.86mol) to m-bromophenol (124.6g, 0.72mol) at the same time in a water bath at 40°C, stir and react for 8h . After the reaction is complete, add about 90 ml of concentrated hydrochloric acid to adjust the pH of the solution to 1. Wash with toluene (100ml×3, that is, use 100ml each time, wash three times in total), extract with ethyl acetate (100ml×3), combine the organic layers and spin dry to obtain a light yellow viscous product, 2-bromo-4 -138.73g of hydroxymandelic acid, with a yield of 78.0%.

Embodiment 2

[0026] Example 2: Synthesis of 2-bromo-4-hydroxyphenylacetic acid

[0027] Add stannous chloride dihydrate (112.8g, 0.50mol) and 230ml of concentrated hydrochloric acid to 2-bromo-4-hydroxymandelic acid (111.17g, 0.45mol), stir, and react in an oil bath at 80°C for 3h. After the reaction is complete, pour it into a beaker and heat it until the solid is completely dissolved. After standing and cooling at room temperature, a solid was precipitated, filtered with suction, washed with water (100ml×3), and recrystallized with water to obtain 90.10 g of 2-bromo-4-hydroxyphenylacetic acid as a white solid with a yield of 86.7%.

Embodiment 3

[0028] Example 3: Preparation of 2,4-Dihydroxyphenylacetic acid

[0029] Add 8-hydroxyquinoline copper (10.56g, 0.03mol) and a 10% aqueous solution containing 120g and 3mol sodium hydroxide to 2-bromo-4-hydroxyphenylacetic acid (69.31g, 0.30mol), stir and heat to 110°C , Reaction 6h. After the reaction is complete, cool to room temperature, filter, acidify the filtrate with dilute hydrochloric acid to pH=3, extract with ethyl acetate (100ml×3), combine the organic layers, dry with anhydrous sodium sulfate, spin dry the organic solvent, and recrystallize with ethanol 40.87 g of 2,4-dihydroxyphenylacetic acid was obtained as a light yellow solid, with a yield of 81%.

[0030] 1 HNMR(400MHz,DMSO-d 6 ,ppm)δ11.96(s,1H),9.24(s,1H),9.08(s,1H),6.83(d,J=8.0Hz,1H), 6.25(d,J=2.0Hz,1H), 6.13(dd,J 1 =8.0Hz,J 2 =2.0Hz, 1H), 3.31(s, 2H) (such as figure 1 Shown).

[0031] MS-EI: 32, 51, 66, 77, 94, 123, 150, 168 (such as figure 2 Shown).

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Abstract

The invention discloses a preparation method of 2,4-dihydroxyphenyl acetic acid, which comprises the following steps: by using m-bromophenol and glyoxalic acid as raw materials, carrying out condensation reaction and acidification to obtain hydroxy o-bromomandelic acid, reducing the hydroxy o-bromomandelic acid to obtain p-hydroxy o-bromophenyl acetic acid, carrying out bromine hydroxylation reaction on the p-hydroxy o-bromophenyl acetic acid in the presence of a catalyst under alkaline conditions, and carrying out acidification to obtain the 2,4-dihydroxyphenyl acetic acid. The method has the advantages of simple and accessible raw materials, simple reaction treatment and higher yield. The obtained intermediate also has important applications.

Description

Technical field [0001] The invention relates to the field of chemical synthesis, in particular to a method for preparing 2,4-dihydroxyphenylacetic acid. Background technique [0002] Hydroxy-substituted phenylacetic acid is an important organic chemical raw material. It can undergo the typical reaction of carboxyl group, methylene hydrogen and benzene ring to generate many useful intermediates. It has a wide range of uses in medicine, agriculture, perfume and dye industries. The synthesis methods of hydroxy-substituted phenylacetic acid are mainly as follows: (1) However, Feijun and others use piperonal as raw material, through Cannizzaro reaction, chlorination, nitrification, hydrolysis, deprotection, etc., to obtain 3,4-dihydroxybenzene Acetic acid, the total yield of this route is 45% (Chemical Reagents, 2005, 27, 623); (2) Zhang Zheng et al. used p-methoxybenzyl chloride as the raw material, through nitrification, isopropylation, demethylation, hydrolysis, etc. Α-isopropyl-4...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/367C07C59/52
CPCC07C51/347C07C51/353C07C51/367
Inventor 邹永徐田龙魏文盛剑飞位文涛
Owner SUN YAT SEN UNIV
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