Preparation method of 2,4,6-trifluorobenzylamine

A technology of trifluorobenzylamine and trifluorobenzonitrile, which is applied in the field of preparation of 2,4,6-trifluorobenzylamine, can solve the problems of high corrosiveness of production equipment, unfavorable large-scale production, unfriendly environment, etc. Low production cost, short synthetic route steps, and environmentally friendly effects

Active Publication Date: 2018-03-09
HANGZHOU ALLSINO CHEM
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The synthesis route has long steps, and it needs to carry out lithiation reaction with n-butyllithium at ultra-low temperature (-55°C-90°C), and thionyl chloride needs to be used in the halogenation

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  • Preparation method of 2,4,6-trifluorobenzylamine
  • Preparation method of 2,4,6-trifluorobenzylamine

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[0026] The invention provides a kind of preparation method of 2,4,6-trifluorobenzylamine, comprises the steps:

[0027] S1. Using pentachlorobenzonitrile as a starting material, perform fluorination reaction with anhydrous potassium fluoride in the first organic solvent to obtain 3,5-dichloro-2,4,6-trifluorobenzonitrile;

[0028] S2a. Add the 3,5-dichloro-2,4,6-trifluorobenzonitrile prepared in step S1 to the second organic solvent, add an organic base, and pass in hydrogen, under the action of the first catalyst, The intermediate 2,4,6-trifluorobenzonitrile was obtained through dechlorination and hydrogenolysis;

[0029] S3. Add the 2,4,6-trifluorobenzonitrile prepared in step S2a to the third organic solvent, add acid, and pass in hydrogen. Under the action of the second catalyst, the intermediate 2,4,6 -Trifluorobenzonitrile is reduced by cyano group to obtain 2,4,6-trifluorobenzylamine.

[0030] In the above technical scheme, after the fluorination reaction is finished, ...

Embodiment 1

[0046]Pentachlorobenzonitrile (20g, 72.6mmol) and anhydrous potassium fluoride (13.9g, 239.2mmol) were put into sulfolane (100mL), heated to 130-140°C under nitrogen protection, and kept for 3h. After the reaction was completed, the reaction liquid was lowered to room temperature, 100 mL of methyl tert-butyl ether and 200 mL of water were added, and the layers were extracted and separated. The organic phase was separated, washed with 100 mL of water, dried over anhydrous sodium sulfate, filtered, and precipitated under reduced pressure to obtain 3,5-dichloro-2,4,6-trifluorobenzonitrile (16.2 g, yield 98.6%), HPLC content 98.9%.

Embodiment 2

[0048] Pentachlorobenzonitrile (20g, 72.6mmol) and anhydrous potassium fluoride (13.9g, 239.2mmol) were put into sulfolane (100mL), heated to 130-140°C under nitrogen protection, and kept for 7h. After the reaction was completed, the reaction liquid was lowered to room temperature, 100 mL of methyl tert-butyl ether and 200 mL of water were added, and the layers were extracted and separated. The organic phase was separated, washed with 100 mL of water, dried over anhydrous sodium sulfate, filtered, and precipitated under reduced pressure to obtain 3,5-dichloro-2,4,6-trifluorobenzonitrile (13.8 g, yield 84.1%), HPLC content 98.2%.

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Abstract

The invention provides a preparation method of 2,4,6-trifluorobenzylamine. The preparation method comprises the following steps: S1, by taking pentachloro benzonitrile as a starting material, adding the pentachloro benzonitrile into anhydrous potassium fluoride for fluorination reaction in a first organic solvent, thus obtaining 3,5-dichloro-2,4,6-trifluoro-cyanophenyl; S2a, adding the 3,5-dichloro-2,4,6-trifluoro-cyanophenyl prepared in the step S1 into a second organic solvent, adding organic alkali, feeding hydrogen, and carrying out dehydrochlorination reaction under the action of a firstcatalyst, thus obtaining 2,4,6-trifluoro-cyanophenyl serving as an intermediate; S3, adding the 2,4,6-trifluoro-cyanophenyl prepared in the step S2a into a third organic solvent, adding acid, feedinghydrogen, and reducing the 2,4,6-trifluoro-cyanophenyl serving as the intermediate through a cyanogroup under the action of a second catalyst, thus obtaining 2,4,6-trifluorobenzylamine. By the adoption of the technical scheme, the preparation method has the advantages that steps of a synthesis route are simple and short, conditions are mild, operation is simple and convenient, the raw materials are low in cost and readily available, and the production cost is low; the catalysts and solvents can be recycled for use, so that pollution is reduced; the preparation method is environmentally friendly and suitable for industrial large-scale production.

Description

technical field [0001] The invention relates to the technical field of medicine and chemical industry, in particular to a preparation method of 2,4,6-trifluorobenzylamine. Background technique [0002] 2,4,6-Trifluorobenzylamine is an important pharmaceutical and pesticide intermediate with high market value. At present, there are few literatures about the synthesis report of this compound. The main synthetic routes are: [0003] ①Marfat, Anthony et al Preparation of nicotinamides as PDE4 Disoenzymes inhibitors, WO9845268 [0004] In this route, 2-bromomethyl-1,3,5-trifluorobenzene is used as a raw material to react with urotropine to form a salt, and then hydrochloric acid is hydrolyzed to obtain 2,4,6-trifluorobenzylamine. However, the starting material 2-bromomethyl-1,3,5-trifluorobenzene cannot be purchased directly from the market and needs to be synthesized through multi-step reactions, which is not suitable for industrial production. [0005] ②Zhou Zhouxi, Shao Ho...

Claims

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Application Information

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IPC IPC(8): C07C209/48C07C211/29
CPCC07C209/48C07C253/30C07C211/29C07C255/50
Inventor 闻建明沈洪良陆国彪施国强
Owner HANGZHOU ALLSINO CHEM
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