Novel method for preparing 2,4,5-trifluoro phenylacetic acid

A technology of trifluorophenylacetic acid and trifluorophenylethyl alcohol, applied in the field of medicine and chemical industry, can solve the problems of low cost and hidden dangers, and achieve the effects of low cost, less discharge of three wastes, and mild reaction conditions

Active Publication Date: 2017-05-31
JIANGSU HANKUO BIOLOGICAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0015] This route has low cost and high yield, and is a method commonly used in industrial production at present. However, it is obvious that highly toxic sodium cyanide is a hidden danger of this process.

Method used

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  • Novel method for preparing 2,4,5-trifluoro phenylacetic acid
  • Novel method for preparing 2,4,5-trifluoro phenylacetic acid
  • Novel method for preparing 2,4,5-trifluoro phenylacetic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0037] 2.8g AlCl 3 Dissolve in 100g of 1,2-dichloroethane, heat to reflux, add 15g of 1,2,4-trifluorobenzene dropwise into the reaction system under vigorous stirring, continue to react at reflux temperature for 6 hours, cool and filter, The filtrate was distilled under reduced pressure at a temperature not higher than 50°C to recover unreacted 1,2-dichloroethane, and the remaining oil was directly used for the next reaction without separation.

Embodiment 2

[0039] 4.1g BF 3 ·C 2 h 5 OC 2 h 5 Dissolve in 100g 1,2-dichloroethane, heat to reflux, add 15g 1,2,4-trifluorobenzene dropwise into the reaction system under vigorous stirring, continue to react at reflux temperature for 8 hours, cool and filter , the filtrate was distilled under reduced pressure at a temperature not higher than 50°C to recover unreacted 1,2-dichloroethane, and the remaining oil was directly used for the next reaction without separation.

Embodiment 3

[0041] The oily product reacted in Example 1 was added to 150ml of distilled water, 4.0g of NaOH was added, and stirred at 30°C for 6 hours. After the reaction, the reaction system was extracted three times with 200ml of dichloromethane, and the organic layer was separated. Wash with water with pH=3 (100ml×3), dry with magnesium sulfate, filter, distill dichloromethane under normal pressure and recover, the remaining 17.8 grams of light yellow oil is 2,4,5-trifluorophenethyl alcohol The purity of the crude product determined by HPLC is 92%, and the two-step yield is 89%. This crude product does not need to be separated and can be directly carried out in the next step.

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Abstract

The invention provides a novel method for preparing 2,4,5-trifluoro-phenylacetic acid. The novel method specifically comprises the following steps: (1) dissolving 1,2,4-trifluoro benzene into 1,2-dihalogenated ethane, carrying out a Friedel-crafts alkylation reaction under catalysis of a lewis acid catalyst, thus preparing 2,4,5-trifluoro halogenated ethylbenzene; (2) hydrolyzing the 2,4,5-trifluoro halogenated ethylbenzene obtained in the step (1) in an alkaline system, thus obtaining 2,4,5-trifluoro phenethyl alcohol; (3) oxidizing the 2,4,5-trifluoro phenethyl alcohol obtained in the step (2), thus obtaining the 2,4,5-trifluoro phenylacetic acid. The novel method disclosed by the invention has the advantages that raw materials are easy to obtain, the reaction is mild, the operation is easy, the cost is low, environment friendliness is realized, no high-toxicity reagent exists, and the like.

Description

technical field [0001] The invention belongs to the field of medicine and chemical industry, and in particular relates to a preparation method of 2,4,5-trifluorophenylacetic acid and its synthetic intermediate 2,4,5-trifluorophenylethanol. Background technique [0002] 2,4,5-Trifluorophenylacetic acid is a key intermediate for the preparation of the hypoglycemic drug sitagliptin. There are currently many studies on the synthesis of this compound. In summary, there are mainly the following synthetic routes: [0003] Route 1: Using 1,2,4-trifluorohalogenated benzene as raw material, condensing with malonate, followed by hydrolysis and decarboxylation, and finally producing 2,4,5-trifluorophenylacetic acid (US2004068141), the details are as follows Shown: [0004] [0005] The raw materials of this route are less available, the atom economy is poor, and it is not suitable for large-scale production. [0006] Route 2: Use 1,2,4-trifluorohalogenated benzene as a raw material...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/16C07C57/58
CPCC07C17/269C07C29/124C07C51/16C07C57/58C07C25/13C07C33/46
Inventor 潘庆华周熹
Owner JIANGSU HANKUO BIOLOGICAL
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