Method for synthesizing trans-4-alkylcyclohexyl benzene structure liquid crystal intermediates and monomers

A technology for the synthesis of cyclohexylbenzene, which is applied to the preparation of heterocyclic compounds, chemical instruments and methods, magnesium organic compounds, etc., can solve the problems of limited conversion rate and achieve the effect of avoiding low yield

Active Publication Date: 2018-01-12
宁夏中星显示材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the conversion rate of configuration conversion is usually limited, and because of the use of strong acid or strong alkaline environment during configuration conversion, unexpected impurities may be brought

Method used

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  • Method for synthesizing trans-4-alkylcyclohexyl benzene structure liquid crystal intermediates and monomers
  • Method for synthesizing trans-4-alkylcyclohexyl benzene structure liquid crystal intermediates and monomers

Examples

Experimental program
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Effect test

Embodiment 1

[0034] 1-fluoro-3-(trans-4-propylcyclohexyl)benzene Synthesis

[0035] In a 500ml three-necked flask, add 5.9g (0.24mol) of magnesium chips and 20ml of THF, and drop in a solution made of 38.5g (0.22mol) of 3-fluorobromobenzene and 140ml of THF to prepare 3-fluorophenylmagnesium bromide. Raise the temperature to 60°C, keep a stable reaction, add dropwise a solution of 31.2g (0.2mol) of 1,4-cyclohexanedione monoethylene glycol ketal and 120ml of toluene, keep stirring for 3 hours after dropping, and cool down to 0°C. Slowly add 200ml of 2N hydrochloric acid while keeping it below 10°C, let stand to separate the upper organic layer, extract the water layer with 120ml of toluene once, combine the organic phases, evaporate the solvent to 100°C, add 1g of p-toluenesulfonic acid, 5g of ethylene glycol, Reflux to separate water for 5h until no water comes out. The reaction solution was washed with aqueous sodium bicarbonate until neutral, and the toluene was evaporated to dryness ...

Embodiment 2

[0043] 1,3-Difluoro-5-(trans-4-pentylcyclohexyl)benzene Synthesis

[0044] In a 500ml three-necked flask, add 5.9g (0.24mol) of magnesium chips and 20ml of THF, and drop in a solution made of 42.5g (0.22mol) of 3,5-difluorobromobenzene and 150ml of THF to prepare 3,5-difluorophenyl magnesium bromide. Raise the temperature to 60°C, keep a stable reaction, add dropwise a solution of 31.2g (0.2mol) of 1,4-cyclohexanedione monoethylene glycol ketal and 120ml of toluene, keep stirring for 3 hours after dropping, and cool down to 0°C. Slowly add 200ml of 2N hydrochloric acid while keeping it below 10°C, let stand to separate the upper organic layer, extract the water layer with 120ml of toluene once, combine the organic phases, evaporate the solvent to 100°C, add 1g of p-toluenesulfonic acid, 5g of ethylene glycol, Reflux to separate water for 5h until no water comes out. The reaction solution was washed with aqueous sodium bicarbonate until neutral, and the toluene was evaporat...

Embodiment 3

[0052] 1-ethoxy-2,3-difluoro-4-(trans-4-propylcyclohexyl)benzene Synthesis

[0053] Into a 500ml three-necked flask, add 170ml of THF and 34.8g (0.22mol) of 2,3-difluorophenetole. Stir and cool down to -78°C, control the temperature below -70°C and add 88ml (0.22mol) of 2.5mol / L butyllithium solution dropwise, and keep warm for 1h after dropping. Keep the temperature controlled below -60°C and add dropwise a solution of 1,4-cyclohexanedione monoethylene glycol ketal 31.2g (0.2mol) and THF 100ml, keep stirring for 1h after dropping, and heat up to 0°C. Slowly add 200ml of 2N hydrochloric acid while keeping below 10°C, let stand to separate the upper organic layer, extract the water layer with 200ml of toluene once, combine the organic phases, evaporate the solvent to 100°C, add 1g of p-toluenesulfonic acid, 5g of ethylene glycol, Reflux to separate water for 5h until no water comes out. The reaction solution was washed with aqueous sodium bicarbonate until neutral, and the ...

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Abstract

The invention discloses a method for synthesizing trans-4-alkylcyclohexyl benzene structure liquid crystal intermediates and monomers and belongs to the technical field of trans-cyclohexyl benzene liquid crystal. The method comprises the following steps: taking a compound with a structural formula shown in the specification as a raw material, carrying out a wittig reaction with a ylide reagent, controlling the reaction temperature to be 50 DEG C below zero to 70 DEG C, and reacting for 1-12 hours; performing catalytic hydrogenation on the obtained reaction product so as to directly obtain substituted 4-alkylcyclohexyl benzene with a high trans-ratio, wherein the structural formula is as shown in the specification; R is C1-C7 straight-chain paraffin; Y1 and Y2 are fluorine or hydrogen but not simultaneously fluorine; when A is hydrogen, the synthesized product is the liquid crystal intermediate; when A is cyano, ethyoxyl, 3,4,5-trifluoro-phenyl, 3,4-difluorophenyl, 4-ethylphenyl, 4-propyl phenyl or (3,4,5-trifluoro-phenyl) difluoromethoxy, the synthesized product is the liquid crystal monomer. The synthetic method disclosed by the invention is simple and high-efficiency, a trans-form is directly obtained by the reaction, the trans-selectivity is high, and the condition that a cis-trans mixture is obtained after catalytic hydrogenation and subjected to further cyclohexyl configuration inversion in the traditional method is avoided.

Description

technical field [0001] The invention belongs to the technical field of trans-cyclohexylbenzene liquid crystals, and relates to a synthesis method of a trans-4-alkylcyclohexylbenzene structure liquid crystal intermediate and a monomer. The synthesis method of the invention is simple and efficient, the reaction can directly obtain the trans structure, the trans selectivity is good, and the further treatment of cyclohexyl configuration conversion after the cis-trans mixture obtained after catalytic hydrogenation in the traditional method is avoided. Background technique [0002] Liquid crystal is an organic substance with certain order between solid state and liquid state, and has photoelectric dynamic scattering characteristics. Its molecules have a variety of liquid crystal phases, such as cholesteric phase, various smectic phases, and nematic phases. According to the different properties of their materials, most liquid crystal materials in various phases have been developed...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C25/18C07C25/24C07C17/354C07C17/263C07C45/59C07C49/697C07D317/72C07F3/02C07C43/225C07C41/18C07C41/20C07C49/753
Inventor 岳刚王志强禹凯王利民关登仕
Owner 宁夏中星显示材料有限公司
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