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Method of preparing high-purity trans-1-(2,2-difluoro-4-propylcyclohexyl)-4-propylbenzene

A technology of propylcyclohexanone and propylbenzene, which is applied in the field of preparation of liquid crystal materials, can solve the problems of low proportion of chiral isomerization mixture, difficulty in obtaining high purity, low proportion, etc.

Active Publication Date: 2019-04-19
HUANGGANG LUBAN PHARM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The ratio of trans-isomer and cis-isomer in the chiral isomerization mixture obtained by this method is not high, resulting in a low ratio of trans-isomer and cis-isomer in the final fluorinated product mixture, and it is difficult to separate isomer products by distillation , it is difficult to obtain high-purity trans-1-(2,2-difluoro-4-propylcyclohexyl)-4-propylbenzene

Method used

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  • Method of preparing high-purity trans-1-(2,2-difluoro-4-propylcyclohexyl)-4-propylbenzene

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preparation example Construction

[0045] The preparation method of the present invention involves the chiral isomerization of 2-(4-propylphenyl)-5-propylcyclohexanone (compound of formula 3) under Lewis acid catalysis. Those skilled in the art know that there are literature-related patents in the prior art that mention the chiral isomerization of cyclohexane (without side chain ketone groups) with a base at high temperature. However, the 2-(4-propylphenyl)-5-propylcyclohexanone (compound of formula 3) involved in the present invention is different from the literature reports, and its cyclohexane structure contains a carbonyl group. The present inventors found that the ideal chiral isomerization reaction could not be achieved under high temperature, base catalysis or alcohol solvent, base catalysis. On the contrary, at high temperature without solvent or under alkali catalysis, the chiral isomerization product develops to a ratio of 50:50, and the reaction at high temperature produces more degradation impuritie...

Embodiment 1

[0067] According to the reaction process shown above, the inventors have investigated the use of potassium carbonate, sodium ethylate, sodium methylate, sodium hydroxide, potassium hydroxide, potassium tert-butoxide, anhydrous lithium chloride, anhydrous aluminum trichloride, three Comparative experiment of chiral isomerization of ketone body formula 3 with fluoromethanesulfonic acid, trifluoroacetic acid, anhydrous zinc chloride, and 15% sulfuric acid.

[0068] Table 1: Chiral isomerization reactions with different catalysts.

[0069]

[0070] Through comparative experiments, referring to patents and other literature reports, the effect of chiral isomerization in alkali is not high, and the chiral isomerization in the opposite direction is obtained under the catalysis of some alkalis. The cis-body in the product becomes larger; unexpectedly, it is found that this compound has better chiral isomerization in Lewis acid, and anhydrous aluminum trichloride has the best chiral ...

Embodiment 2

[0072] In this embodiment, the inventor further investigated the catalyst is aluminum trichloride, in the solvent dichloromethane, chloroform, 1,2-dichloroethane, acetonitrile, THF or toluene chiral isomerization reaction comparison .

[0073] Table 2: Chiral isomerization reaction of catalyst aluminum trichloride in different solvents.

[0074]

[0075] Through comparative experiments, the ratio of chiral isomerization in dichloromethane is the highest, and the yield is the highest.

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Abstract

The present invention provides a method for preparing high-purity trans-1-(2,2-difluoro-4-propylcyclohexyl)-4-propylbenzene at a high yield. The method comprises the following steps: a Lewis acid is used to catalyze a chiral isomerization reaction of a mixture formula 3 to obtain high-purity (trans:cis > 90:10) trans-2-(4-propylphenyl)-5-propylcyclohexanone (formula 2); and the high-purity (trans:cis > 90:10) trans-2-(4-propylphenyl)-5-propylcyclohexanone (formula 2) undergoes a fluorination reaction to prepare the high-purity trans-1-(2,2-difluoro-4-propylcyclohexyl)-4-propylbenzene (formula1). The method has the advantages of high yield, easiness in separation and purification of the product, few wastes, low cost and easiness in industrialization.

Description

technical field [0001] The present invention relates to the preparation field of liquid crystal material; Specifically, the present invention relates to high-purity trans-1-(2,2-difluoro-4-propylcyclohexyl)-4-propylbenzene (formula 1) and The preparation method of its key intermediate trans-2-(4-propylphenyl)-5-propylcyclohexanone (Formula 2). Background technique [0002] Liquid crystal materials are an important part of the liquid crystal display device LCD industry. Liquid crystal material is the basic material of LCD and one of the key optoelectronic special materials for producing LCD devices. It endows LCD devices with various excellent properties. Liquid crystal material is a special material in the field of electronic information. It is a kind of rod-shaped organic compound with anisotropy. [0003] The fluorine atom has a smaller atomic radius of 0.135nm which is similar to the hydrogen atom radius of 0.11nm, so the fluorine atom is used to replace the hydrogen at...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C23/18C07C17/18C07C49/657C07C45/67C07C45/81
CPCC07B2200/09C07C17/18C07C45/67C07C45/81C07C2601/14C07C23/18C07C49/657
Inventor 杨小龙胡新良张建军陈潜杨铁波
Owner HUANGGANG LUBAN PHARM
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