Method for preparing 3, 4-difluorobenzaldehyde

A technology of difluorobenzaldehyde and difluorobromobenzene, which is applied in the field of preparation of 3,4-difluorobenzaldehyde, can solve the problems of increased impurities, inconsistent thinking, and low product yield, and achieve the effect of improving the reaction yield

Active Publication Date: 2016-08-17
BENGBU CHINA SYNCHEM TECH CO LTD
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  • Abstract
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Problems solved by technology

[0003] There are reports in the open literature that the method of 2,4-difluorobenzaldehyde uses the process of diazotizing the amino group to add fluorine, which is inconsistent with the idea of ​​this patent
In addition, the preparation of 3,4-difluorobenzaldehyde from raw material 3,4-difluorobromobenzene usually adopts the method of directly making 3,4-difluorobromobenzene and metal magnesium into Grignard reagent, and then reacting with DMF method, but found in the research process, because 3,4-difluorobromoben

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  • Method for preparing 3, 4-difluorobenzaldehyde

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Embodiment 1

[0017] 5L four-necked bottle, mechanical stirring, nitrogen protection, sequentially add magnesium strips, 400g tetrahydrofuran and iodine particles, then add 41.7g 2-chloropropane at room temperature, trigger after 10min, the maximum temperature is 40°C, drop the temperature at 30-40°C Add the prepared 2-chloropropane solution, drop it in 4.5 hours, keep it warm for 1 hour, and there is basically no magnesium strip. The temperature was lowered, and a solution of 3,4-difluorobromobenzene (654g of 3,4-difluorobromobenzene and 700g of tetrahydrofuran) was added dropwise at 0-10°C, and the addition was completed within 50 minutes. Insulation reaction, up to room temperature. After the reaction was completed, the temperature was lowered, and a DMF solution (291.3 g of DMF and 300 g of tetrahydrofuran) was added dropwise at 0-10° C. for 40 min. Control the temperature below 10°C, add 700g of water dropwise, then add concentrated hydrochloric acid dropwise to adjust the pH to about...

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Abstract

The invention discloses a method for preparing 3, 4-difluorobenzaldehyde, and relates to the technical field of organic synthesis. The method includes carrying out Grignard exchange reaction on 3, 4-difluoro bromobenzene, tetrahydrofuran and a Grignard reagent to obtain first reaction products; carrying out reaction on the first reaction products and N, N-dimethylformamide to obtain second reaction products; treating the second reaction products to obtain the 3, 4-difluorobenzaldehyde. The 3, 4-difluoro bromobenzene is used as a raw material, and the tetrahydrofuran is used as a solvent. The method has the advantages that the Grignard exchange reaction is carried out on the 3, 4-difluoro bromobenzene and the freshly prepared Grignard reagent which is isopropylmagnesium chloride, and accordingly the problem of large quantities of generated byproducts due to excessively high reaction temperatures when 3, 4-difluoro bromobenzene and a Grignard reagent which is metal magnesium can be solved; the reaction is carried out on the N, N-dimethylformamide and the products already subjected to Grignard exchange, so that the 3, 4-difluorobenzaldehyde can be prepared, and the reaction yield can be increased.

Description

Technical field: [0001] The invention relates to the technical field of organic synthesis, in particular to a preparation method of 3,4-difluorobenzaldehyde. Background technique: [0002] 3,4-Difluorobenzaldehyde is the raw material of the new anti-platelet aggregation drug ticagrelor. Ticagrelor was successfully developed by AstraZeneca in the United States. It is the world's first reversible conjugated oral P2Y12 adenosine Phosphoreceptor antagonists. [0003] Public documents report the method of 2,4-difluorobenzaldehyde, which adopts the process of diazotizing amino groups to add fluorine, which is inconsistent with the idea of ​​this patent. In addition, the preparation of 3,4-difluorobenzaldehyde from raw material 3,4-difluorobromobenzene usually adopts the method of directly making 3,4-difluorobromobenzene and metal magnesium into Grignard reagent, and then reacting with DMF method, but found in the research process, because 3,4-difluorobromobenzene and metal magne...

Claims

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Application Information

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IPC IPC(8): C07C47/55C07C45/45C07F3/02
CPCC07C45/455C07F3/02C07C47/55
Inventor 杨青张浩赵士民徐剑霄
Owner BENGBU CHINA SYNCHEM TECH CO LTD
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