Method for synthesizing (trans)-4-alkyl-3-alkene biphenyl derivative monomer liquid crystals
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A synthesis method and derivative technology, applied in liquid crystal materials, chemical instruments and methods, hydrocarbons, etc., can solve problems such as cost increase, catalyst cannot be recycled and applied, limited industrial use, etc. The effect of mild production and reaction conditions
Active Publication Date: 2011-04-13
SHIJIAZHUANG CHENGZHI YONGHUA DISPLAY MATERIALS CO LTD
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The next step of coupling with bromoalkylbiphenyl requires the use of expensive catalyst PdCl 2 dppf, this kind of catalyst cannot be recycled and used mechanically, resulting in an increase in cost
These will limit the industrial application of this method
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Embodiment 1
[0039] Step 1, the preparation of 2-[2-(4-bromophenyl)ethene]-[1,3]dioxane
[0040] Add 75g of chemical formula II (p-bromocinnamaldehyde), 31g of ethylene glycol, 500ml of toluene, and 1g of p-toluenesulfonic acid into a 1L three-necked flask. Water, when no more water comes out after one hour, cool down to room temperature with a cold water bath, wash the reaction solution with water until the pH value of the washing water is neutral, dry with anhydrous sodium sulfate for 5 hours, distill off toluene under reduced pressure, and the residual The substance is heated and dissolved with 0.5 times of toluene and 1 times of petroleum ether, then frozen, filtered to obtain 75g of white crystal 2-[2-(4-bromobenzene)ethylene]-[1,3]dioxane, yield 84% .
[0041] Step 2, the preparation of 2-[2-(4'-methyl-biphenyl-4-)-ethylene]-[1,3-dioxane]
[0042] Add 27.2g of p-tolueneboronic acid, 51g of 2-[2-(4-bromobenzene)ethylene]-[1,3]dioxane, 25.5g of sodium carbonate, and 200ml of dimethyl...
Embodiment 2
[0054] The raw material that this embodiment uses is chemistry III (p-bromophenylpropanal), and its reaction steps are:
[0055] Step 1, Preparation of 2-[2-(4-bromophenyl)ethyl]-[1,3]dioxane
[0056] Using Chemistry III (p-bromophenylpropionaldehyde) as raw material, adopting the same reaction conditions as step one of Example 1, directly prepare 2-[2-(4-bromophenyl) ethyl]-[1,3] di Oxygen Pentacycline.
[0057] Step 2, the preparation of 2-[2-(4'-methyl-biphenyl-4-)-ethyl]-[1,3-dioxopentacycline]
[0058] The 2-[2-(4-bromophenyl) ethyl]-[1,3]dioxane prepared in step 1 of this example is used as raw material, and the reaction conditions are the same as step 2 in Example 1 to prepare 2 -[2-(4'-Methyl-biphenyl-4-)-ethyl]-[1,3-dioxolane].
[0059] Step 3, the preparation of 3-(4'-methylbiphenyl-4-)propionaldehyde
[0060] Same as Step 4 of Example 1.
[0061] Step 4. Preparation of (cis, trans)-4'-methyl-4-(pent-3-enyl)biphenyl
[0062] Same as Step 5 of Example 1.
[006...
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Abstract
The invention discloses a method for synthesizing (trans)-4-alkyl-3-alkene biphenyl derivative monomer liquid crystals, and belongs to the field of the preparation of monomer liquid crystal materials. The method comprises the following steps of: performing condensation of para-bromo cinnamaldehyde or 3-(4-bromo-phenyl)-propionaldehyde serving as a raw material and alcohol to prepare acetal, and performing a cross-coupling reaction of the acetal and 4-alkylbenzene borate in solvent under the catalytic action of palladium to obtain a biphenyl intermediate; and removing protective group alcohol of the biphenyl intermediate to produce an intermediate, performing a witting reaction of the intermediate and alkyltriphenylphosphonium halide in the presence of potassium tert-butoxide to produce a (cis, trans)-4-alkyl-3-alkene biphenyl derivative, and performing the inversion of cis and trans configuration to obtain the (trans)-4-alkyl-3-alkene biphenyl derivative monomer liquid crystals. The method has the advantages of low cost, high quality of products and mild reaction condition, and the expanded production is easy to perform. Therefore, the method is particularly suitable for the industrial production of the (trans)-4-alkyl-3-alkene biphenyl derivative monomer liquid crystals.
Description
technical field [0001] The invention relates to a method for synthesizing monomeric liquid crystals of (trans)-4-alkyl-3-alkenyl biphenyl derivatives, and belongs to the field of preparation of monomeric liquid crystal materials. Background technique [0002] (Trans)-4-Alkyl-3-alkenyl biphenyl derivative monomer liquid crystal has good chemical stability, good mutual solubility, especially high k33 / k11 value and good steepness , which is of great significance for realizing high-channel count display. It can be applied to mixed liquid crystals of TN, STN, TFT and other display modes. [0003] In 2001, Merck's patent DE10218975A1 disclosed two (trans)-4-alkyl-3-alkenyl biphenyl derivative monomer liquid crystal synthesis routes: [0004] [0005] This synthetic route uses extremely flammable and explosive butyllithium in the presence of TMEDA, at 20 ° C to capture the hydrogen on the methyl group connected to the benzene ring with weak acidity, and generate a lithium subs...
Claims
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