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Method for preparing 2,3-dimethyl benzaldehyde

A technology of dimethylbenzaldehyde and dimethylhalogenated benzene, which is applied in the chemical field, can solve the problems of butyllithium use safety risks, high price, unsatisfactory reaction yield, and no large-scale commercial sources, etc., reaching Low price, easy operation, reasonable design effect

Inactive Publication Date: 2016-04-20
SUOANKE SHANGHAI INVESTMENT CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Obviously, the raw materials required by the above two methods do not have large-scale commercial sources, and the cost is high
In addition, related literature reports that aromatic aldehydes can be prepared by reacting brominated aromatic hydrocarbons with N,N-dimethylformamide and hydrolyzing them after reacting with n-butyllithium at a low temperature of -78 degrees, such as Journal of Labeled Compounds and Radiopharmaceuticals, 2004, 47, 821-835, but low temperature The reaction conditions are harsh, and the safety risk and price of butyllithium are high, and the reaction yield is not very ideal.

Method used

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  • Method for preparing 2,3-dimethyl benzaldehyde
  • Method for preparing 2,3-dimethyl benzaldehyde

Examples

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Embodiment 1

[0011] Under nitrogen protection, 24 grams of magnesium chips (1.0mol) and 160 milliliters of tetrahydrofuran were added to a reaction flask, and a mixture of 18.5 grams of 2,3-dimethylbromobenzene (0.1mol) and 100 milliliters of tetrahydrofuran was added dropwise under stirring at room temperature. solution to initiate the reaction, and then continue to dropwise add a mixed solution of 166.5 grams of 2,3-dimethylbromobenzene (0.9mol) and 1000 milliliters of tetrahydrofuran. Cool the resulting Grignard reagent with an ice bath, add dropwise a mixture of 73 grams of N,N-dimethylformamide (1.0mol) and 300 ml of tetrahydrofuran, control the reaction temperature not higher than 30 degrees, and drop it at room temperature The reaction was continued for 2 hours. After the reaction, add 1000 ml of saturated ammonium chloride solution for hydrolysis for 1 hour, then let stand to separate the organic phase, extract the water phase once with ethyl acetate, combine the organic phases, wa...

Embodiment 2

[0013] Under nitrogen protection, 26.4 grams of magnesium chips (1.1mol) and 160 milliliters of tetrahydrofuran were added in a reaction flask, and a mixture of 18.5 grams of 2,3-dimethylbromobenzene (0.1mol) and 100 milliliters of tetrahydrofuran was added dropwise under stirring at room temperature. liquid to initiate the reaction, and then continue to dropwise add a mixed solution of 166.5 grams of 2,3-dimethylbromobenzene (0.9mol) and 1000 milliliters of tetrahydrofuran, and after the addition is complete, reflux for 1 hour. Cool the resulting Grignard reagent with an ice bath, add dropwise a mixture of 73 grams of N,N-dimethylformamide (1.0mol) and 300 ml of tetrahydrofuran, control the reaction temperature not higher than 20 degrees, and drop it at room temperature The reaction was continued for 2 hours. After the reaction, add 1000 ml of saturated ammonium chloride solution for hydrolysis for 1 hour, then let stand to separate the organic phase, extract the water phase ...

Embodiment 3

[0015] Under nitrogen protection, 24 grams of magnesium chips (1mol) and 160 milliliters of tetrahydrofuran were added to a reaction flask, and a mixture of 18.5 grams of 2,3-dimethylbromobenzene (0.1 mol) and 100 milliliters of tetrahydrofuran was added dropwise with stirring at room temperature , Initiate the reaction, then continue to dropwise add a mixed solution of 166.5 grams of 2,3-dimethylbromobenzene (0.9mol) and 1000 milliliters of tetrahydrofuran, after the addition is complete, reflux for 1 hour. Cool the resulting Grignard reagent with an ice bath, add dropwise a mixture of 73 grams of N,N-dimethylformamide (2.0 mol) and 300 ml of tetrahydrofuran, control the reaction temperature not higher than 20 degrees, and drop it at room temperature The reaction was continued for 2 hours. After the reaction, add 1000 ml of saturated ammonium chloride solution for hydrolysis for 1 hour, then let stand to separate the organic phase, extract the water phase once with ethyl acet...

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Abstract

The invention discloses a method for preparing 2,3-dimethyl benzaldehyde. The method includes the steps that firstly, under the protection of nitrogen, a Grignard reagent is prepared from 2,3-dimethyl benzene halide; secondly, the Grignard reagent and N,N-dimethyl formamide are reacted; finally, the 2,3-dimethyl benzaldehyde is prepared through hydrolyzing, purifying and separating. The method is reasonable in design, mild in reaction condition, simple in technology and easy and convenient to operate; the obtained 2,3-dimethyl benzaldehyde is a key intermediate for synthesizing dexmedetomidine hydrochloride, the sources of the raw materials are rich, and industrial applicability is achieved.

Description

technical field [0001] The invention belongs to the field of chemistry, and relates to a method for synthesizing a key intermediate of dexmedetomidine hydrochloride, in particular to a method for preparing 2,3-dimethylbenzaldehyde. Background technique [0002] Dexmedetomidine hydrochloride is an α2-adrenoceptor agonist, its chemical name is: (+)-4-(S)-[1-(2,3-dimethylphenyl)ethyl]-1H - Imidazole hydrochloride, for sedation during tracheal intubation and mechanical ventilation in surgical patients under general anesthesia, see [(a) Karjalainen, A.J, Virtanen, R.N., Savolainen, E.J. Opticalisomerofanimidazolederivativemedetimidineasanalpha-2-receptoragonist, US4910214[P] , 1990-05-20]. 2,3-dimethylbenzaldehyde is an important intermediate for the synthesis of dexmedetomidine hydrochloride, and its synthetic methods mainly include the oxidation of 2,3-dimethylbenzyl alcohol and the oxidation of 2,3-dimethylbenzonitrile Reduction, see [(a) Thomas, O., Johannes, G.D.V., Vries,...

Claims

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Application Information

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IPC IPC(8): C07C45/42C07C47/542
CPCC07C45/42C07C47/542
Inventor 毛侦军姜新东林旭锋李青坡游剑
Owner SUOANKE SHANGHAI INVESTMENT CO LTD
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