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Preparation method of 1, 7, 8- trifluoro-2- naphthol and derivative thereof

A technology of naphthol and dihydronaphthalene, applied in the field 1, can solve the problems of expensive palladium carbon catalyst and the danger of hydrogen, and achieve the effect of low cost, low price and simple operation steps

Active Publication Date: 2014-03-19
NANKAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Another disadvantage of this method is that the palladium carbon catalyst used in the hydrogen reduction method is expensive, the high pressure reaction and the use of hydrogen are dangerous

Method used

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  • Preparation method of 1, 7, 8- trifluoro-2- naphthol and derivative thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Embodiment 1: the preparation of 1,7,8-trifluoro-2-naphthol

[0020] 0.92g (0.005mol) of 7,8-difluoro-2-naphthol was dissolved in 35mL of acetonitrile in a 100mL three-necked flask, and heated to 50°C. Under continuous stirring, 5.35 g (0.0136 mol) of F-TEDA-BF4 was added, and the stirring was continued for 15 min. The solvent was rotovapped to obtain 0.54 g of a yellow solid, namely: 1,1,7,8-tetrafluoro-1,2-dihydronaphthalen-2-one.

[0021] Take 0.5 g of yellow solid, add 30 mL of acetonitrile, and heat to 50°C. Add 5mL of 0.95g (0.006mol) sodium formaldehyde sulfoxylate dihydrate (Sodium formaldehydesulfoxylate dihydrate) aqueous solution, and continue stirring at this temperature for 2.5h.

[0022] After filtering, the filtrate was separated into layers, and the organic phase was washed with 10 mL of 10% hydrochloric acid and washed with saturated brine three times, 5 mL each time. Dry over anhydrous sodium sulfate for 2 h, evaporate the solvent, and dry to obtain...

Embodiment 2

[0025] Embodiment 2: 1,7, the preparation of 8-trifluoro-2-naphthol

[0026] Take 0.92g (0.005mol) of 7,8-difluoro-2-naphthol and 35mL of acetonitrile into a 100mL three-necked flask, and raise the temperature to 50°C. Under constant stirring, 9.8 g (0.025 mol) of F-TEDA-BF4 was added. Stirring was continued for 20 min; a solid precipitated out. The solvent was rotovaped to obtain 0.48 g of a yellow solid. Namely: 1,1,7,8-tetrafluoro-1,2-dihydronaphthalene-2-one.

[0027] Take 1.0 g of 1,1,7,8-tetrafluoro-1,2-dihydronaphthalene-2-one, add 50 mL of acetonitrile, and heat to 55°C. Add 20mL of 3.8g (0.024mol) sodium formaldehyde sulfoxylate dihydrate aqueous solution. Stirring was continued at this temperature for 3h, resulting in a small amount of white solid.

[0028] After filtration, the filtrate was separated into layers, and the organic phase was washed with 30 mL of 10% hydrochloric acid, washed three times with saturated brine, dried over anhydrous sodium sulfate for ...

Embodiment 3

[0029] Embodiment 3: the preparation of 1,7,8-trifluoro-2-naphthol

[0030] Take 9.2g (0.05mol) of 7,8-difluoro-2-naphthol and 200mL of acetonitrile into a 500mL three-necked flask, and raise the temperature to 55°C. Under continuous stirring, 78.7 g (0.02 mol) of F-TEDA-BF4 was added. Stirring was continued for 30 minutes, and the reaction solution was filtered through celite.

[0031] The reaction solution obtained above in the fluorination step was heated to 50°C. Add 50mL of 7.3g (0.06mol) sodium formaldehyde sulfoxylate aqueous solution; continue stirring at this temperature for 2.5h, resulting in a small amount of white solid.

[0032] Filtration, the filtrate was separated, and the organic phase was taken, washed with 30 mL of 10% hydrochloric acid and then washed with saturated brine three times, dried over anhydrous sodium sulfate for 2 h, evaporated the solvent, and dried to obtain 7.3 g of a yellow solid. After recrystallization with toluene and petroleum ether [...

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Abstract

The invention relates to a preparation method of 1, 7, 8- trifluoro-2- naphthol and a derivative thereof, which comprises the following steps: carrying out electrophilic fluoridation of a derivative of 7, 8- difluoro-2- naphthol and a fluoridating agent in an organic solvent; and then reducing with a reducing agent. The 1, 7, 8- trifluoro-2- naphthol prepared by the invention can be used as a fluorin-contained single liquid crystal. The invention has the advantages of simple process and equipment, easy operation and low cost; and products prepared by the invention have high purity above 96% and is suitable to commercialized and mass preparation and production to meet the increasing current market demand.

Description

technical field [0001] The invention relates to a preparation method of 1,7,8-trifluoro-2-naphthol (hereinafter referred to as trifluoronaphthol) and derivatives thereof. Background technique [0002] 1,7,8-trifluoro-2-naphthol is an important intermediate of fluorine-containing liquid crystal materials developed in recent years, through which 1,7,8-trifluoro-2,6 - Liquid crystal molecules of diradical structure. The liquid crystal molecules with this structure can be used to improve current mainstream liquid crystal materials and develop new liquid crystal display technologies, and have broad development prospects. EP1544187 etc. have reported the preparation method of 1,7,8-trifluoro-2-naphthol, and it is to use novel NF class electrophilic fluorinating reagent MEC-31 to 7,8-difluoro-2-naphthol (DFNT ) after fluorination, the intermediate product was reduced with hydrogen under palladium carbon catalysis. The disadvantage of this method is that the NF type electrophilic...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C39/38C07C37/07
Inventor 赵国锋陈波刘琪苗永妍
Owner NANKAI UNIV
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