Synthetic method of symmetric diacrylate liquid crystal monomer compound and compound

Abstract

The invention provides a synthetic method of a symmetric diacrylate liquid crystal monomer compound and a compound, a compound I reacts with a reagent II to obtain a compound III, and the molar weight ratio of the compound I to the reagent II is 1: (1.2-10); reacting the compound IV with a compound V to obtain a compound VI, wherein the molar ratio of the compound V to the compound IV is 1: (1.8-2.6); the compound VI and the compound III react to obtain a target compound, the birefringence of the obtained target compound is higher than that of an existing acrylate liquid crystal medium, the symmetrical diacrylate liquid crystal monomer is novel in structure, and the synthesis method is short in step and easy to operate.

Description

Technical Field

[0001] The present application belongs to the technical field of liquid crystal materials, and in particular relates to a synthesis method and compound of a symmetrical diacrylate liquid crystal monomer compound. Background Art

[0002] Polarized volume holographic grating (PVG) waveguide technology is a new type of diffraction waveguide AR display technology. While retaining the high efficiency and low cost advantages of volume holographic waveguide technology, this technology breaks through the limitations of the original volume holographic waveguide in terms of field of view (FOV) and color display. Compared with the existing diffraction waveguide solution, PVG waveguide technology has unique potential and advantages in terms of display performance, light energy utilization, power consumption, weight and volume, and cost control.

[0003] Liquid crystal monomer materials are one of the important components of optical waveguides. High-performance liquid crystal monomer materials play an important role in improving the performance of waveguide devices. Acrylic liquid crystal is one of the common liquid crystal materials and is often used in diffraction optical waveguides. The birefringence of acrylic liquid crystal media currently used in PVG gratings is generally between 0.08 and 0.16. When this type of liquid crystal material is used in PVG, the birefringence is low, which limits the development of PVG optical waveguides in AR glasses. Therefore, it is of great significance to develop acrylic liquid crystal monomers with novel structures and high birefringence. Summary of the invention

[0004] In order to solve or alleviate the problems of the prior art, in the first aspect, the embodiments of the present application provide a method for synthesizing a symmetrical diacrylate liquid crystal monomer compound, and the specific synthesis route is as follows: , wherein n=2~10; step 1: compound I reacts with reagent II to obtain compound III, and the molar ratio of compound I to compound II is 1:(1.2~10); Step 2: Compound IV and compound V react to obtain compound VI, and the molar ratio of compound V to compound IV is 1:(1.8-2.6); Step 3: Compound VI reacts with compound III to obtain target compound VII.

[0005] As a preferred embodiment of the present application, the solvent used in step 1 is one or more of dichloromethane, dichloroethane, carbon tetrachloride, tetrahydrofuran, dioxane, and diethyl ether.

[0006] As a preferred embodiment of the present application, the reagent II is one or more of phosphorus oxychloride, phosphorus trichloride, phosphorus pentachloride, thionyl chloride, and oxalyl chloride. During the reaction of step 1, pyridine, 4-dimethylaminopyridine, N,N-dimethylformamide, and N,N-dimethylacetamide can be added or not. The reaction time is 0.5h~6h, and the reaction temperature is -20℃~100℃.

[0007] As a preferred embodiment of the present application, the solvent used in step 2 is one or more of methanol, ethanol, toluene, dioxane, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide, and the catalyst used is palladium chloride, palladium acetate, tetrakistriphenylphosphine palladium, bis(di-tert-butyl-4-dimethylaminophenylphosphine)palladium chloride, bis(triphenylphosphine)palladium dichloride, 1,1'-bisdiphenylphosphinodiferrocenepalladium dichloride. One or more of the catalyst, the molar amount of the catalyst is 0.005% to 0.1% of the molar amount of compound V; the base used is one or more of alkali metal carbonates, alkali metal bicarbonates, alkali metal hydroxides, and alkali metal phosphates, and the molar ratio of compound V to the base is 1: (4 to 10).

[0008] As a preferred embodiment of the present application, step 2 is carried out under the protection of an inert gas, the reaction temperature is 40° C. to 120° C., and the reaction time is 1 h to 16 h.

[0009] As a preferred embodiment of the present application, X in the compound IV is Br or I.

[0010] As a preferred embodiment of the present application, the solvent used in step 3 is one or more of diethyl ether, tetrahydrofuran, dioxane, dichloromethane, and dichloroethane; the base used in the reaction is one or more of diethylamine, triethylamine, N,N-diisopropylethylamine, an aqueous solution of an alkali metal carbonate, an aqueous solution of an alkali metal bicarbonate, and an alkali metal phosphate, the molar ratio of compound VI to the base is 1:(2~10), the reaction temperature is 0°C~45°C, and the reaction time is 1h~8h.

[0011] In a second aspect, the present application also provides a symmetrical diacrylate liquid crystal monomer compound, which is prepared by the synthesis method described in any one of the first aspects, and the compound has the structural formula: , where n=2~10; When R 1 =R 2 =H, R 3 =R 4 =H or F or Me; When R 1 =H, R 2 =F,R 3 =R4 =H; When R 1 = F, R 2 =R 3 =R 4 =H; When R 1 =H, R 2 =Me,R 3 =R 4 =H; When R 1 =Me, R 2 =R 3 =R 4 =H; When R 1 =R 2 = F, R 3 =R 4 =H; When R 1 =R 2 =Me, R 3 =R 4 =H.

[0012] Compared with the prior art, the embodiment of the present application provides a method for synthesizing a symmetrical diacrylate liquid crystal monomer compound. The birefringence of the compound of formula VII obtained by the synthesis method of the present application is between 0.175 and 0.185, which is much higher than the birefringence of the existing acrylate liquid crystal medium. The symmetrical diacrylate liquid crystal monomer has a novel structure, and the synthesis method has a short step and is simple to operate. DETAILED DESCRIPTION

[0013] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only embodiments of a part of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present application. Example 1

[0014] When X=I, n=6, R 1 =Me,R 2 =R 3 =R 4 =H, the specific structure of the compound is as follows: Step 1: Add 70 g of 4-(6-(acryloyloxy)hexyloxy)benzoic acid to a 1000 mL round-bottom flask, then add 300 mL of tetrahydrofuran and 500 mg of N,N-dimethylformamide, stir evenly and cool to 0°C, add 60.78 g of oxalyl chloride dropwise, slowly warm to room temperature after the addition is complete, stir at 45°C for 6 hours, spin dry the solvent to obtain 4-(6-(acryloyloxy)hexyloxy)benzoyl chloride crude product: 74 g, light yellow oil, the crude product will be directly used in subsequent reactions.

[0015] Step 2: In a 1000 mL round-bottom flask, 50.0 g of 1,4-phenylenediboronic acid bis(pinacol) ester, 70.9 g of 4-iodo-2-methylphenol, 36.4 g of sodium hydroxide, 500 mL of toluene and 100 mL of water were added in sequence, stirred evenly, replaced with argon three times, and then 1.75 g of tetrakistriphenylphosphine palladium was added, replaced with argon three times, and then heated to 110°C. After reacting for 8 hours, the reaction was stopped and cooled to 25°C. The solvent was spin-dried, and the residue was poured into 200 mL of water, washed three times with ethyl acetate, and the aqueous phase was collected. The pH of the system was adjusted to 5 with 1 mol / L dilute hydrochloric acid. At this time, a large amount of solid was generated. Filter, collect the solid, and dry to obtain 22.5 g of 3,3''-dimethyl-[1,1':4',1''-triphenyl]-4,4''-diol as a white solid with a purity of 95.4%.

[0016] Step 3: Add 22.5 g of 3,3''-dimethyl-[1,1':4',1''-triphenyl]-4,4''-diol and 200 mL of tetrahydrofuran to a 500 mL round-bottom flask, stir evenly, then add 250 mL of saturated sodium bicarbonate aqueous solution, cool to 0°C, slowly add 73.52 g of 4-(6-(acryloyloxy)hexyloxy)benzoyl chloride dropwise, raise the temperature to 25°C after the addition is complete, continue stirring for 6 hours and then stop the reaction. 100 mL of water was added to the reaction solution, and then extracted three times with ethyl acetate, washed once with saturated sodium chloride, and then dried with 50 g of anhydrous magnesium sulfate. After filtering to remove the magnesium sulfate, the resulting liquid was concentrated to dryness, and then crystallized by mixing ethanol and n-heptane to obtain 3,3''-dimethyl-[1,1':4',1''-triphenyl]-4,4''-di(4-((6-(propenyloxy)hexyl)oxy)benzoate) 37.5 g, white solid, purity 98.68%, birefringence: 0.178, nuclear magnetic data: 1H NMR (500 MHz, Chloroform-d) δ 8.19 (dd, J = 8.9, 2.6 Hz, 4H), 7.66 (d, J = 2.5Hz, 3H), 7.56 – 7.42 (m, 4H), 7.30 – 7.15 (m, 3H), 6.99 (dd, J = 8.9, 2.3 Hz, 4H), 6.41 (dd, J = 17.3, 1.7 Hz, 2H), 6.13 (ddd, J = 17.4, 10.4, 2.3 Hz, 2H), 5.83 (dd, J = 10.4, 1.7 Hz, 2H), 4.19 (t, J = 6.6 Hz, 4H), 4.06 (t, J = 6.5Hz, 4H), 2.30 (d, J = 8.7 Hz, 6H), 1.85 (p, J = 6.8 Hz, 4H), 1.74 (p, J = 6.9Hz, 4H), 1.51 (dp, J = 30.4, 7.5, 7.0 Hz, 8H). Example 2

[0017] When X=I, n=6, R 1 =R 2 =R 3 =R 4 =H, the specific structure of the compound is as follows: Step 1: Add 70 g of 4-(6-(acryloyloxy)hexyloxy)benzoic acid to a 500 mL round-bottom flask, then add 142.4 g of dichlorothionyl, heat to 80 ° C, react for 3 hours, cool to 25 ° C, spin-dry the dichlorothionyl to obtain 4-(6-(acryloyloxy)hexyloxy)benzoyl chloride crude product: 73.8 g, light yellow oil, the crude product will be directly used in subsequent reactions.

[0018] Step 2: In a 1000 mL round-bottom flask, 50.0 g of 1,4-phenyldiboronic acid bis(pinacol) ester, 66.66 g of p-iodophenol, 125.6 g of potassium carbonate, 500 mL of ethanol and 100 mL of water were added in sequence, and the mixture was replaced with argon three times after stirring evenly. Then 1.1 g of 1,1'-bis(diphenylphosphino)ferrocenepalladium dichloride was added, and the mixture was replaced with argon three times. The mixture was then heated to 80°C, the reaction was stopped after stirring for 16 hours, and the mixture was cooled to 25°C. The solvent was dried by spin drying, the residue was poured into 200 mL of water, washed three times with ethyl acetate, the aqueous phase was collected, and the pH of the system was adjusted to 5 with 1 mol / L dilute hydrochloric acid. A large amount of solid was generated at this time. The solid was collected by suction filtration and dried to obtain 21.1 g of [1,1':4',1''-triphenyl]-4,4''-diol as a white solid with a purity of 96.1%.

[0019] Step 3: Add 21.1 g of [1,1':4',1''-triphenyl]-4,4''-diol, 200 mL of dichloromethane, and 24.4 g of triethylamine to a 500 mL round-bottom flask. Stir evenly and then cool to 0°C. Slowly drop 70 g of 4-(6-(acryloyloxy)hexyloxy)benzoyl chloride. After the addition is complete, heat to 35°C and continue stirring for 6 hours before stopping the reaction. 300 mL of water was added to the reaction solution, and then extracted three times with ethyl acetate, washed once with saturated sodium chloride, and then dried with 50 g of anhydrous magnesium sulfate. After filtering to remove the magnesium sulfate, the resulting liquid was concentrated to dryness, and then crystallized by mixing ethanol and n-heptane to obtain 36.4 g of [1,1':4',1''-triphenyl]-4,4''-di(4-((6-(propenyloxy)hexyl)oxy)benzoic acid diester) as a white solid with a purity of 98.83%. The birefringence index was 0.183. The nuclear magnetic data were as follows: 1H NMR (500 MHz, Chloroform-d) δ 8.19 (dd, J =8.9, 2.6 Hz, 4H), 7.61 (d, J = 2.4 Hz, 4H), 7.48 – 7.36 (m, 8H), 6.99 (m,4H), 6.41 (dd, J = 17.3, 1.7 Hz, 2H), 6.13 (ddd, J = 17.4, 10.4, 2.3 Hz, 2H), 5.83 (dd, J = 10.4, 1.7 Hz, 2H), 4.19 (t, J = 6.6 Hz, 4H), 4.06 (t, J = 6.5Hz, 4H), 1.85 (p, J = 6.8 Hz, 4H), 1.74 (p, J = 6.9 Hz, 4H), 1.51 (dp, J =30. 4, 7.5, 7.0 Hz, 8H).

[0020] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for synthesizing a symmetrical diacrylate liquid crystal monomer compound, characterized in that: The specific synthetic route is as follows: , where n=2~10; Step 1: Compound I reacts with reagent II to obtain compound III, and the molar ratio of compound I to reagent II is 1:(1.2-10); Step 2: Compound IV and compound V react to obtain compound VI, and the molar ratio of compound V to compound IV is 1:(1.8-2.6); Step 3: Compound VI reacts with compound III to obtain target compound VII.

2. The method for synthesizing a symmetrical diacrylate liquid crystal monomer compound according to claim 1, characterized in that: The solvent used in step 1 is one or more of dichloromethane, dichloroethane, carbon tetrachloride, tetrahydrofuran, dioxane, and ether.

3. The method for synthesizing a symmetrical diacrylate liquid crystal monomer compound according to claim 1, characterized in that: The reagent II is one or more of phosphorus oxychloride, phosphorus trichloride, phosphorus pentachloride, thionyl chloride, and oxalyl chloride. The reaction temperature of step 1 is -20°C to 100°C, and the reaction time is 0.5h to 6h.

4. The method for synthesizing a symmetrical diacrylate liquid crystal monomer compound according to claim 1, characterized in that: The solvent used in step 2 is one or more of methanol, ethanol, toluene, dioxane, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide; the catalyst used is one or more of palladium chloride, palladium acetate, tetrakistriphenylphosphine palladium, bis(di-tert-butyl-4-dimethylaminophenylphosphine)palladium chloride, bis(triphenylphosphine)palladium dichloride, and 1,1'-bisdiphenylphosphinoferrocenepalladium dichloride, and the molar amount of the catalyst is 0.005% to 0.1% of the molar amount of compound V; the base used is one or more of alkali metal carbonates, alkali metal bicarbonates, alkali metal hydroxides, and alkali metal phosphates, and the molar ratio of compound V to the base is 1: (4 to 10).

5. The method for synthesizing a symmetrical diacrylate liquid crystal monomer compound according to claim 3, characterized in that: Step 2 is carried out under the protection of an inert gas, the reaction temperature is 40° C. to 120° C., and the reaction time is 1 h to 16 h.

6. The method for synthesizing a symmetrical diacrylate liquid crystal monomer compound according to claim 1, characterized in that: In the compound IV, X is Br or I.

7. The method for synthesizing a symmetrical diacrylate liquid crystal monomer compound according to claim 1, characterized in that: The solvent used in step 3 is one or more of diethyl ether, tetrahydrofuran, dioxane, dichloromethane, and dichloroethane; the base used in the reaction is one or more of diethylamine, triethylamine, N,N-diisopropylethylamine, an aqueous solution of an alkali metal carbonate, an aqueous solution of an alkali metal bicarbonate, and an alkali metal phosphate, and the molar ratio of the compound VI to the base is 1:(2-10); the reaction temperature is 0°C-45°C, and the reaction time is 1h-8h.

8. A symmetrical diacrylate liquid crystal monomer compound, characterized in that: Prepared by the synthesis method according to any one of claims 1 to 7, the compound has the structural formula: , where n=2~10; When R1=R2=H, R3=R4=H or F or Me; When R1=H, R2=F, R3=R4=H; When R1=F, R2=R3=R4=H; When R1=H, R2=Me, R3=R4=H; When R1=Me, R2=R3=R4=H; When R1=R2=F, R3=R4=H; When R1=R2=Me, R3=R4=H.

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