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Method for preparing fluorine-containing benzoxazole liquid crystal compound

A technology of liquid crystal compounds and benzoxazoles, which is applied in the field of materials, can solve the problems of many reaction steps, high cost, and low yield, and achieve the effect of simple operation, low cost, and high yield

Active Publication Date: 2013-09-18
XIAN CAIJING OPTO ELECTRICAL SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] There are mainly two synthetic methods of benzoxazole compounds. The classic preparation method mainly uses carboxylic acid or acid chloride and o-aminophenol to react under strong acid conditions to construct the benzoxazole structure, but this method has many reaction steps, It is not suitable for mass production due to problems such as high cost, large pollution, complicated post-processing, and low product yield.
The improved method mainly utilizes the reaction of aromatic aldehyde and o-aminophenol to obtain the benzoxazole structure under oxidation conditions. Relatively speaking, the improved method has mild reaction conditions and is easy to operate, but the improved method still has the problems of many steps and low yield
Moreover, in the classic method or improved method, the aryl carboxylic acid or aryl acid chloride or aromatic aldehyde intermediates used are basically not commercially available, and the synthesis requires multi-step reactions, and there are problems such as harsh conditions, many steps, and low yields.

Method used

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  • Method for preparing fluorine-containing benzoxazole liquid crystal compound
  • Method for preparing fluorine-containing benzoxazole liquid crystal compound
  • Method for preparing fluorine-containing benzoxazole liquid crystal compound

Examples

Experimental program
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Effect test

Embodiment 1

[0026] Taking the preparation of 2-(4'-octyloxy-2',3'-difluorobiphenyl)benzoxazole as an example, the preparation method is as follows:

[0027] 1. Preparation of 4′-octyloxy-2′,3′-difluorobiphenylformaldehyde

[0028] Under nitrogen protection at a flow rate of 0.6mL / min, 20.8g (0.10mol) of 4-hydroxy-2,3-difluorobromobenzene, 41.4g (0.3mol) of potassium carbonate, 19.0mL (0.11mol) of 1-bromo Add octane into a three-necked flask containing 240mL N,N-dimethylformamide, raise the temperature to 70°C under stirring at 350 rpm and react for 6 hours, and then add 16.5g (0.11mol) 4-methanol to the three-necked flask Acylphenylboronic acid, 1.2g (1mmol) tetrakis (triphenylphosphine) palladium and 40mL distilled water, 4-hydroxy-2,3-difluorobromobenzene and 1-bromooctane, potassium carbonate, 4-formylphenylboronic acid , The molar ratio of tetrakis(triphenylphosphine)palladium, N,N-dimethylformamide, and distilled water is 1:1.1:3:1.1:0.01:30:22, the temperature is raised to 100°C, a...

Embodiment 2

[0037] In step 2 of the preparation of 2-(4′-octyloxy-2′,3′-difluorobiphenyl)benzoxazole in Example 1, 3.04 g (0.01 mol) of 4′-octyloxy- Add 2′,3′-difluorobiphenyl formaldehyde and 1.2g (0.011mol) of o-aminophenol into a three-necked flask filled with 30mL of 1,2-dichloroethane, stir at 350 rpm, and reflux at 80°C for 5 hours, then 2.3g (0.01mol) 2,3-dichloro-5,6-dicyanobenzoquinone was added to the three-necked flask, and 4′-octyloxy-2′,3′-difluorobiphenylformaldehyde The molar ratio of o-aminophenol, 2,3-dichloro-5,6-dicyanobenzoquinone, and 1,2-dichloroethane is 1:1.1:1.0:38, react at 10°C for 8 hours, other steps Same as in Example 1, 2-(4′-octyloxy-2′,3′-difluorobiphenyl)benzoxazole was obtained with a total yield of 58%.

Embodiment 3

[0039] In step 2 of the preparation of 2-(4′-octyloxy-2′,3′-difluorobiphenyl)benzoxazole in Example 1, 3.04 g (0.01 mol) of 4′-octyloxy- Add 2′,3′-difluorobiphenyl formaldehyde and 1.2g (0.011mol) of o-aminophenol into a three-necked flask filled with 60mL of 1,2-dichloroethane, stir at 350 rpm, and reflux at 80°C for 5 hours, then add 3.4g (0.015mol) 2,3-dichloro-5,6-dicyanobenzoquinone into the three-necked flask, 4′-octyloxy-2′,3′-difluorobiphenylformaldehyde The molar ratio of o-aminophenol, 2,3-dichloro-5,6-dicyanobenzoquinone, and 1,2-dichloroethane is 1:1.1:1.5:76, react at 50°C for 3 hours, other steps Same as in Example 1, 2-(4′-octyloxy-2′,3′-difluorobiphenyl)benzoxazole was obtained with a total yield of 61%.

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Abstract

The invention discloses a method for preparing a fluorine-containing benzoxazole liquid crystal compound. The compound has a structural formula shown in the description, wherein R refers to C2-16 straight-chain paraffin; X, Y and Z refer to respectively independent fluorine or hydrogen, X, Y and Z refer to hydrogen alternatively, and M refers to hydrogen, chlorine or nitro. The preparation method comprises the following steps: by taking 4-hydroxyl fluorinated bromobenzene, 1-bromoalkane and 4-formylphenylboronic acid as reaction raw materials, preparing 4'-alkoxyfluorobiphenylcarboxaldehyde, and reacting 4'-alkoxyfluorobiphenylcarboxaldehyde with aminophenol to prepare the fluorine-containing benzoxazole liquid crystal compound under the action of an oxidant. Compared with the classical method and the improved method, the method has the advantages of fewer steps, simple operation, low cost and high yield and can be used for preparing fluorine-containing benzoxazole liquid crystal.

Description

technical field [0001] The invention belongs to the technical field of materials, and in particular relates to a preparation method of fluorine-containing benzoxazole liquid crystal compounds. Background technique [0002] With the rapid development of liquid crystal displays, more and more attention has been paid to the development and research of new liquid crystal materials. Among the fields of liquid crystal materials, heteroaromatic liquid crystal materials are one of the important research fields of liquid crystals. Due to the presence of heteroatoms in the structure of aromatic heterocyclic compounds, the polarity of the compound and the force between molecules will change, which will affect the liquid crystallinity and photophysical properties of the material. [0003] At present, heterocyclic liquid crystal materials, especially benzoheterocyclic liquid crystal materials, have received extensive attention due to their special physical and chemical properties, such ...

Claims

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Application Information

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IPC IPC(8): C07D263/57
Inventor 陈新兵陈沛安忠维徐亦为
Owner XIAN CAIJING OPTO ELECTRICAL SCI & TECH
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