4,5-disubstituted phenanthrene and hydrophenanthrene liquid crystal compound and preparation method thereof
A technology of liquid crystal composition and compound, applied in the field of liquid crystal
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Embodiment 1
[0080] Example 1 Compound 2-(2,3-difluoro-4-n-propylphenyl)-4,5-difluoro-7-(3,5-difluoro-4-trifluoromethoxyphenyl)phenanthrene preparation of
[0081]
[0082] The first step: the preparation of 2-amino-5-bromo-3-fluorobenzoic acid hydrobromide
[0083]
[0084] 153g of 2-amino-3-fluorobenzoic acid dispersed in 1500ml of chloroform, 175g of bromine dissolved in 150ml of chloroform was slowly added dropwise to the above chloroform solution, and stirred at room temperature overnight, filtered the next day, and the filter cake After washing with DCM and vacuum drying, 276 g of 2-amino-5-bromo-3-fluorobenzoic acid hydrobromide was obtained as a yellow powder.
[0085] The second step: Preparation of 4,4'-dibromo-6,6'-difluorobiphenyl-2,2'-dicarboxylic acid
[0086]
[0087] Dissolve 75g of copper sulfate pentahydrate in 300ml of water, add 230ml of 25% ammonia water under stirring, and cool to 0°C with an ice-salt bath. An aqueous solution prepared by 20.8 g of hydroxy...
Embodiment 2
[0115] Example 2 Preparation of compound 2-(3,5-difluoro-4-(trifluoromethoxy)phenyl)-4,5-difluorophenanthrene
[0116]
[0117] Step 1: Preparation of (4-bromo-6,6'-difluorobiphenyl-2,2'-yl)dimethanol
[0118]
[0119] 35g of 4,4'-dibromo-6,6'-difluorobiphenyl-2,2'-dicarboxylate was dissolved in 300ml of dry THF, and the clear solution was cooled to -20°C with a liquid nitrogen bath , slowly add 7g of lithium aluminum hydride in batches, keep stirring for 1 hour, slowly rise to room temperature, stir and react for 5 hours, add water and 20ml of 15% sodium hydroxide aqueous solution dropwise to the reaction solution to quench the reaction, suction filter , the filter cake was washed with THF, the filtrate was concentrated to dryness under reduced pressure, and the residue was separated and purified with a silica gel column to obtain 23.5 g of (4-bromo-6,6'-difluorobiphenyl-2,2'-yl)dimethanol, Yellow oil.
[0120] The second step: the preparation of 4-bromo-6,6'-difluoro...
Embodiment 3
[0134] Preparation of Example 3 Compound 4,5-bis(trifluoromethyl)-2-(3,4,5-trifluorophenyl)-9,10-dihydrophenanthrene
[0135]
[0136] Step 1: Preparation of 6,6'-bis(trifluoromethyl)biphenyl-2,2'-dicarboxylic acid
[0137]
[0138] According to the same operation method as the second step of Example 1, 6,6' can be prepared by replacing 2-amino-5-bromo-3-fluorobenzoic acid hydrobromide with 2-amino-3-trifluoromethylbenzoic acid -Bis(trifluoromethyl)biphenyl-2,2'-dicarboxylic acid, a yellow solid was obtained.
[0139] The second step: Preparation of methyl 6,6'-bis(trifluoromethyl)biphenyl-2,2'-dicarboxylate
[0140]
[0141] According to the same operation method as the third step of Example 1, 6,6'-bis(trifluoromethyl)biphenyl-2,2'-dicarboxylic acid was used instead of 4,4'-dibromo-6,6'- Difluorobiphenyl-2,2'-dicarboxylic acid can be used to prepare methyl 6,6'-bis(trifluoromethyl)biphenyl-2,2'-dicarboxylate as white crystals.
[0142] The third step: Preparation...
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