Preparation method of terminal alkene-containing diphenylacetylene liquid crystal compound

Abstract

The invention provides a preparation method of a terminal alkene-containing diphenylacetylene liquid crystal compound. The preparation method comprises the following steps: fully dissolving a compound of a general formula A in an organic solvent; in a protective gas environment, controlling the temperature at-80 DEG C to 0 DEG C, adding an organic lithium reagent, and reacting for 0.2-6 hours; and controlling the temperature at-80 DEG C to 10 DEG C, adding a compound with a general formula B, and reacting for 0.5-10 hours to obtain the terminal alkene-containing diphenylacetylene liquid crystal compound (a compound with a general formula P). The preparation method provided by the invention is low in cost, high in yield, high in purity, safe in reaction and simple in post-treatment; and meanwhile, the reaction kettle can be directly prepared by a one-pot method during large-scale production, so that the problems of repeated replacement of the reaction kettle and repeated heating and cooling of the reaction kettle in multi-step reaction are avoided, the production time is greatly saved, and the production cost is reduced.

Description

Technical Field

[0001] The invention belongs to the field of organic synthesis, and in particular relates to a method for preparing a tolanyl liquid crystal compound containing terminal olefins. Background Art

[0002] Liquid crystal display (LCD) has achieved rapid development due to its small size, light weight, low power consumption and excellent display quality, and has been widely used in portable electronic information products. With the accelerated development of liquid crystal display technology, higher requirements are also put forward for liquid crystal materials. Some common requirements for liquid crystal compounds, including the phase transition temperature, optical anisotropy, dielectric anisotropy, viscosity, etc. of liquid crystal compounds, have a great influence on the final application of liquid crystal materials. Liquid crystal display elements containing liquid crystal compositions with large absolute values ​​of dielectric anisotropy can reduce the base voltage value, reduce the driving voltage, and can further reduce the consumed electrical power. Liquid crystal display elements containing liquid crystal compositions with low threshold voltage can effectively reduce display power consumption, especially in consumables (such as mobile phones, tablets and other portable electronic products) will have a longer battery life.

[0003] Monomer liquid crystals containing γ-alkenyl chains on the benzene ring generally have higher K 33 / K 11 It has good solubility with other liquid crystals, a wide liquid crystal phase, low viscosity and good steepness, and is a liquid crystal compound with excellent performance. At the same time, the introduction of fluorine atoms into the liquid crystal molecules can reduce the viscosity of the liquid crystal. These properties are conducive to improving the response speed of the liquid crystal, with a good response speed in the TN mode and a good steepness in the STN mode. For example, It has been applied in liquid crystal display elements with good results. Therefore, it is of great value to prepare high-quality diphenylacetylene liquid crystal compounds containing terminal olefins.

[0004] There are three main synthesis methods currently.

[0005] Method 1:

[0006]

[0007] This method is used to prepare allyl magnesium bromide When the reaction is carried out, the temperature needs to be strictly controlled, otherwise a large amount of self-coupling products will be present, and in the last step, when bis-(tri-phenylphosphine)palladium dichloride (PdCl2(PPh3)2 is used as a catalyst for Sonogashira cross-coupling, there is a serious Heck side reaction, some terminal olefins participate in the reaction, and the product quality is poor and the purity is low.

[0008] Method 2:

[0009]

[0010] This method was carried out with ethyl p-iodobenzoate Preparation of ethyl 4-(2-{4-[(acetyloxy)methyl]phenyl}ethynyl)benzoate During the process, due to the presence of CuI, a Glaser side reaction will occur, producing 2wt.% to 10wt.% of 1,3-diyne impurities, which are very difficult to purify, affecting the product quality and the effective utilization of raw materials. In addition, in the last step of the Grignard coupling reaction, there is a small amount of terminal olefin double bond migration, which will pose a great challenge to the purification of the product. It also involves a Grignard reaction, which is a dangerous process with a high degree of danger.

[0011] Method 3:

[0012]

[0013] This method has a long synthesis route and high raw material cost. The last step requires triphenylphosphine salt. The Wittig reaction has high anhydrous requirements and is not suitable for industrial production. The phosphine oxide produced after the reaction is difficult to remove and contains many impurities, which affects the product quality.

[0014] In the prior art, the synthesis method of diphenylacetylene liquid crystal compounds containing terminal olefins has the problems of long reaction route, high cost, low yield, low purity, difficult post-treatment, and high reaction risk. Therefore, how to provide a synthesis method of acetylene liquid crystal compounds containing terminal olefins with a short synthesis route, low cost, high yield, high purity, safe reaction, and simple post-treatment has become an urgent problem to be solved. Summary of the invention

[0015] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing a diphenylacetylene liquid crystal compound containing terminal olefins. The preparation method provided by the present invention has low cost, high yield, high purity, safe reaction, and simple post-treatment; at the same time, it can be directly prepared by a one-pot method during large-scale production, avoiding the problem of multiple replacement of the reaction kettle in multi-step reactions and multiple heating and cooling of the reaction kettle, greatly saving production time and reducing production costs.

[0016] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0017] The present invention provides a method for preparing a tolanyl liquid crystal compound containing terminal olefins, and the preparation method of the present invention comprises the following steps:

[0018] (1) fully dissolving the compound of formula A in an organic solvent;

[0019] (2) Under a protective gas environment, the temperature is controlled at -80°C to 0°C, an organic lithium reagent is added, and the reaction is carried out for 0.2 to 6 hours;

[0020] (3) Control the temperature at -80°C to 10°C, add the compound of general formula B, and react for 0.5 to 10 hours to obtain the compound of general formula P. The reaction is as follows:

[0021]

[0022] Among them, the ring and ring Each independently expresses

[0023] ring and ring Each independently expresses

[0024] R1 represents -F, -Cl, -Br or -I;

[0025] n1 and n2 each independently represent an integer from 0 to 1, such as 0 or 1; when n1 is 0, the alkynyl group is directly connected to the benzene ring structure, and when n2 is 0, the alkynyl group is directly connected to the benzene ring structure;

[0026] n3 and n3′ each independently represent an integer of 1-3, for example, 0, 1, 2 or 3.

[0027] In some embodiments of the invention, n3 is the same as n3'.

[0028] In some embodiments of the present invention, the compound of formula A is selected from the group consisting of:

[0029]

[0030]

[0031] as well as

[0032]

[0033] In some embodiments of the present invention, the compound of formula B is selected from the group consisting of:

[0034]

[0035] as well as

[0036]

[0037] In some embodiments of the present invention, the preparation method of the present invention comprises the following steps:

[0038] (1) fully dissolving the compound of formula A and an organic base in an organic solvent;

[0039] (2) Under a protective gas environment, the temperature is controlled at -80°C to 0°C, an organic lithium reagent is added, and the reaction is carried out for 0.2 to 6 hours;

[0040] (3) Control the temperature at -80°C to 10°C, add the compound of general formula B, and react for 0.5 to 10 hours to obtain the compound of general formula P.

[0041] In some embodiments of the present invention, the organic solvent is selected from diethyl ether, methyl tert-butyl ether, ethylene glycol dimethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, or a combination thereof.

[0042] In some embodiments of the present invention, the protective gas is selected from nitrogen or argon.

[0043] In some embodiments of the present invention, the organic base is selected from potassium tert-butoxide, sodium tert-butoxide, or a combination thereof.

[0044] In some embodiments of the present invention, the organolithium reagent is selected from n-butyllithium, sec-butyllithium, tert-butyllithium, or a combination thereof.

[0045] In some embodiments of the present invention, the molar ratio of the compound of formula A to the organolithium reagent is 1:2 to 1:4 (for example, it can be 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9, 1:3, 1:3.1, 1:3.2, 1:3.3, 1:3.4, 1:3.5, 1:3.6, 1:3.7, 1:3.8, 1:3.9, 1:4, etc., but not limited to the values ​​listed above, and other unlisted values ​​within the above numerical range are also applicable); preferably, the molar ratio of the compound of formula A to the organolithium reagent is 1:2.1 to 1:3.

[0046] In some embodiments of the present invention, the molar ratio of the organolithium reagent to the organic base is 1:0.9 to 1:1.5 (for example, it can be 1:0.9, 1:0.95, 1:1, 1:1.05, 1:1.1, 1:1.15, 1:1.2, 1:1.25, 1:1.3, 1:1.35, 1:1.4, 1:1.45, 1:1.5, etc., but not limited to the values ​​listed above, and other unlisted values ​​within the above numerical range are also applicable); preferably, the molar ratio of the organolithium reagent to the organic base is 1:0.95 to 1:1.2.

[0047] In some embodiments of the present invention, the molar ratio of the compound of general formula A to the compound of general formula B is 1:2 to 1:4 (for example, it can be 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9, 1:3, 1:3.1, 1:3.2, 1:3.3, 1:3.4, 1:3.5, 1:3.6, 1:3.7, 1:3.8, 1:3.9, 1:4, etc., but not limited to the values ​​listed above, and other unlisted values ​​within the above numerical range are also applicable); preferably, the molar ratio of the compound of general formula A to the compound of general formula B is 1:2 to 1:2.5.

[0048] In some embodiments of the present invention, the reaction temperature of step (2) is -80°C to 0°C (for example, it can be -80°C, -75°C, -70°C, -65°C, -60°C, -55°C, -50°C, -45°C, -40°C, -35°C, -30°C, -25°C, -20°C, -15°C, -10°C, -5°C, 0°C, etc., but is not limited to the values ​​listed above, and other values ​​not listed within the above numerical range are also applicable); preferably, the reaction temperature of step (2) is -70°C to -10°C, and more preferably -60°C to -10°C.

[0049] In some embodiments of the present invention, in order to better improve the reaction yield and product purity, the reaction temperature of step (2) is -50°C to -10°C.

[0050] In some embodiments of the present invention, the reaction temperature of step (3) is -80°C to 10°C (for example, it can be -80°C, -75°C, -70°C, -65°C, -60°C, -55°C, -50°C, -45°C, -40°C, -35°C, -30°C, -25°C, -20°C, -15°C, -10°C, -5°C, 0°C, 5°C, 10°C, etc., but is not limited to the values ​​listed above, and other values ​​not listed within the above numerical range are also applicable); preferably, the reaction temperature of step (3) is -50°C to -10°C, and more preferably -30°C to -20°C.

[0051] In some embodiments of the present invention, the reaction time of step (2) is 0.2 to 6 h (for example, it can be 0.2 h, 0.3 h, 0.4 h, 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h, 6 h, etc., but is not limited to the values ​​listed above, and other values ​​not listed within the above numerical range are also applicable); preferably, the reaction time of step (2) is 0.4 to 2.5 h.

[0052] In the present invention, the reaction time has a certain influence on the purity and yield of the diphenylacetylene liquid crystal compound containing terminal olefins. The reaction in step (2) is an alkali hydrogenation reaction. If the reaction time is too short, the reaction may not proceed sufficiently. If the reaction time is too long, by-products may be generated.

[0053] In some embodiments of the present invention, the reaction time of step (3) is 0.5 to 10 h (for example, it can be 0.5 h, 0.6 h, 0.7 h, 0.8 h, 0.9 h, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, etc., but is not limited to the values ​​listed above, and other values ​​not listed within the above numerical range are also applicable). Preferably, the reaction time of step (3) is 0.6 to 3 h.

[0054] In some embodiments of the present invention, the post-treatment is divided into two steps. The white solid obtained in the first step of post-treatment is a crude product, which has a mass difference with the final obtained diphenylethylene liquid crystal compound containing terminal olefins. The difference is not only the by-products produced during the reaction process, but may also contain products that are not completely purified.

[0055] The preparation method of the present invention adopts a one-pot method and a combination of specific reaction conditions so that the preparation method can quickly and simply prepare a diphenylacetylene liquid crystal compound containing terminal olefins, with a purity of more than 99.6% and a yield of more than 70%. The selection of the above specific conditions can improve the reaction yield and product purity.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] The invention obtains a preparation method of a diphenylacetylene liquid crystal compound containing terminal olefins by selecting an organic lithium reagent, an organic solvent and reaction conditions. The preparation method has low cost, safe reaction and simple post-treatment. The purity of the obtained product is as high as 99.6% and the yield is more than 70%. At the same time, the one-pot method can be directly used for large-scale production, thereby avoiding the problem of multiple replacement of reaction kettles and multiple heating and cooling of the reaction kettles in multi-step reactions, greatly saving production time and reducing production costs. DETAILED DESCRIPTION

[0058] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the following examples are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. In the following examples, the compounds and related reagents used can be purchased from the market.

[0060] Example 1

[0061] This embodiment provides a method for preparing a terminal olefin-containing tolanthyl liquid crystal compound P-1, and the reaction formula is as follows:

[0062]

[0063] The operation steps are as follows: In a 250ml three-necked flask, 10.3g (50mmol) of compound A-1 (1-methyl-4-[2-(4-methylphenyl)ethynyl]benzene) and 13.44g (120mmol) of potassium tert-butoxide are fully dissolved in tetrahydrofuran, and under a nitrogen environment, the temperature is controlled at -40℃~-30℃, 48ml (2.5M, 120mmol) of n-butyl lithium is added, and the reaction is carried out for 0.5h, and the temperature is controlled at -30℃~-20℃, and 8.4g (110mmol) of compound B-2 (allyl chloride) is added, and the reaction is carried out for 2h; liquid separation, extraction, and combination of organic phases are carried out, washed with water, dried, dissolved through a column, and the solvent is evaporated to obtain 13g of a white solid. The mixture was recrystallized with ethanol, frozen, filtered and dried to obtain 12.5 g of compound P-1 (1,2-bis(4-butenylphenyl)acetylene) as a white solid (purity: 99.91%, yield: 87.4%).

[0064] The mass spectrum data of compound P-1 are: 189 (8%), 202 (32%), 203 (8%), 204 (100%), 205 (19%), 245 (100%), 246 (30%), 286 (51%), 287 (13%).

[0065] Example 2

[0066] This embodiment provides a method for preparing a terminal olefin-containing tolanthyl liquid crystal compound P-2, and the reaction formula is as follows:

[0067]

[0068] The operation steps are as follows: In a 250ml three-necked flask, 12.1g (50mmol) of compound A-2 (2-fluoro-4-[2-(3-fluoro-4-methylphenyl)ethynyl]-1-methylbenzene) and 11.52g (120mmol) of sodium tert-butoxide are fully dissolved in tetrahydrofuran, and under a nitrogen environment, the temperature is controlled at -40°C to -30°C, 92ml (1.3M, 120mmol) of sec-butyl lithium is added, and the reaction is carried out for 1h, and the temperature is controlled at -30°C to -20°C, and 13.32g (110mmol) of compound B-3 (allyl bromide) is added, and the reaction is carried out for 1h; the organic phases are separated, extracted, and combined, washed with water, dried, dissolved through a column, and the solvent is evaporated to obtain 15g of a white solid. Recrystallize with ethanol, freeze, filter and dry to obtain 14.5 g of compound P-2 (1-(but-3-en-1-yl)-4-{2-[4-(but-3-en-1-yl)-3-fluorophenyl]ethynyl}-2-fluorobenzene) as a white solid (purity: 99.92%, yield: 90%).

[0069] The mass spectrum data of compound P-2 are: 220 (10%), 225 (8%), 238 (30%), 239 (8%), 240 (95%), 241 (17%), 281 (100%), 282 (30%), 322 (48%), 323 (11%).

[0070] Example 3

[0071] This embodiment provides a method for preparing a terminal olefin-containing tolanthyl liquid crystal compound P-3, and the reaction formula is as follows:

[0072]

[0073] The operation steps are as follows: In a 250ml three-necked flask, 15.76g (40mmol) of compound A-9 (2-fluoro-4-(4-{2-[4-(3-fluoro-4-methylphenyl)phenyl]ethynyl}phenyl)-1-methylbenzene) is fully dissolved in 2-methyltetrahydrofuran, and under a nitrogen environment, the temperature is controlled at -50℃~-40℃, 70ml (1.3M, 91mmol) of tert-butyl lithium is added, and the reaction is carried out for 2h, and the temperature is controlled at -30℃~-20℃, 10.64g (88mmol) of compound B-3 (allyl bromide) is added, and the reaction is carried out for 3h; liquid separation, extraction, and combination of organic phases are carried out, washed with water, dried, dissolved through a column, and the solvent is evaporated to obtain 18g of a white solid. Recrystallize with toluene:ethanol (1:3), freeze, filter and dry to obtain 16.8 g of compound P-3 (1-(but-3-en-1-yl)-4-[4-(2-{4-[4-(but-3-en-1-yl)-3-fluorophenyl]phenyl}ethynyl)phenyl]-2-fluorobenzene) as a white solid (purity: 99.88%, yield 88%).

[0074] The mass spectrum data of compound P-3 are: 272 (10%), 277 (7%), 390 (28%), 391 (8%), 392 (92%), 393 (16%), 433 (100%), 434 (30%), 474 (43%), 475 (10%).

[0075] Embodiment 4:

[0076] This embodiment provides a method for preparing a terminal olefin-containing tolanthyl liquid crystal compound P-4, and the reaction formula is as follows:

[0077]

[0078] The operation steps are as follows: In a 250ml three-necked flask, 11.8g (50mmol) of compound A-3 (2-methoxy-4-methyl-1-[2-(4-methylphenyl)ethynyl]benzene) and 11.52g (120mmol) of sodium tert-butoxide are fully dissolved in tetrahydrofuran, and under a nitrogen environment, the temperature is controlled at -40℃~-30℃, 92ml (1.3M, 120mmol) of sec-butyl lithium is added, and the reaction is carried out for 1h, and the temperature is controlled at -30℃~-20℃, and 18.5g (110mmol) of compound B-4 (allyl iodide) is added, and the reaction is carried out for 1h; liquid separation, extraction, and combination of organic phases are carried out, washed with water, dried, dissolved through a column, and the solvent is evaporated to obtain 15.2g of a white solid. Recrystallize with ethanol, freeze, filter and dry to obtain 14.6 g of compound P-4 (4-(but-3-en-1-yl)-1-{2-[4-(but-3-en-1-yl)phenyl]ethynyl}-2-methoxybenzene) as a white solid (purity: 99.92%, yield: 87.4%).

[0079] The mass spectrum data of compound P-4 are: 219 (10%), 233 (8%), 234 (92%), 235 (16%), 275 (100%), 276 (31%), 301 (33%), 316 (48%), 317 (10%).

[0080] Example 5

[0081] This embodiment provides a method for preparing a terminal olefin-containing tolanthyl liquid crystal compound P-1, and the reaction formula is as follows:

[0082]

[0083] The operation steps are as follows: In a 250ml three-necked flask, 10.3g (50mmol) of compound A-1, (1-methyl-4-[2-(4-methylphenyl)ethynyl]benzene), and 13.44g (120mmol) of potassium tert-butoxide are fully dissolved in tetrahydrofuran, and under a nitrogen environment, the temperature is controlled at -40℃~-30℃, 48ml (2.5M, 120mmol) of n-butyl lithium is added, and the reaction is carried out for 0.5h, and the temperature is controlled at -30℃~-20℃, and 7.64g (100mmol) of compound B-2 (allyl chloride) is added, and the reaction is carried out for 2h; liquid separation, extraction, and combination of organic phases are carried out, washed with water, dried, dissolved through a column, and the solvent is evaporated to obtain 12.5g of a white solid. The mixture was recrystallized with ethanol, frozen, filtered and dried to obtain 12 g of compound P-1 (1,2-bis(4-butenylphenyl)acetylene) as a white solid (purity: 99.90%, yield: 83.9%).

[0084] The mass spectrum data of compound P-1 are: 189 (8%), 202 (32%), 203 (8%), 204 (100%), 205 (19%), 245 (100%), 246 (30%), 286 (51%), 287 (13%).

[0085] Example 6

[0086] This embodiment provides a method for preparing a terminal olefin-containing tolanthyl liquid crystal compound P-1, and the reaction formula is as follows:

[0087]

[0088] The operation steps are as follows: In a 250ml three-necked flask, 10.3g (50mmol) of compound A-1 (1-methyl-4-[2-(4-methylphenyl)ethynyl]benzene) and 13.44g (120mmol) of potassium tert-butoxide are fully dissolved in tetrahydrofuran, and under a nitrogen environment, the temperature is controlled at -40℃~-30℃, 48ml (2.5M, 120mmol) of n-butyl lithium is added, and the reaction is carried out for 0.5h, and the temperature is controlled at -30℃~-20℃, and 9.94g (130mmol) of compound B-2 (allyl chloride) is added, and the reaction is carried out for 2h; the organic phases are separated, extracted, and combined, washed with water, dried, dissolved through a column, and the solvent is evaporated to obtain 12.3g of a white solid. The mixture was recrystallized with ethanol, frozen, filtered and dried to obtain 11.7 g of compound P-1 (1,2-bis(4-butenylphenyl)acetylene) as a white solid (purity: 99.84%, yield: 81.8%).

[0089] The mass spectrum data of compound P-1 are: 189 (8%), 202 (32%), 203 (8%), 204 (100%), 205 (19%), 245 (100%), 246 (30%), 286 (51%), 287 (13%).

[0090] Example 7

[0091] This embodiment provides a method for preparing a terminal olefin-containing tolanthyl liquid crystal compound P-1, and the reaction formula is as follows:

[0092]

[0093] The operation steps are as follows: In a 250ml three-necked flask, 10.3g (50mmol) of compound A-1 (1-methyl-4-[2-(4-methylphenyl)ethynyl]benzene) and 13.44g (120mmol) of potassium tert-butoxide are fully dissolved in tetrahydrofuran, and under a nitrogen environment, the temperature is controlled at -40℃~-30℃, 48ml (2.5M, 120mmol) of n-butyl lithium is added, and the reaction is carried out for 25min, and the temperature is controlled at -30℃~-20℃, 8.4g (110mmol) of compound B-2 (allyl chloride) is added, and the reaction is carried out for 2h; liquid separation, extraction, and combination of organic phases are carried out, washed with water, dried, dissolved through a column, and the solvent is evaporated to obtain 12.5g of a white solid. The mixture was recrystallized with ethanol, frozen, filtered and dried to obtain 11.5 g of compound P-1 (1,2-bis(4-butenylphenyl)acetylene) as a white solid (purity: 99.90%, yield: 80.4%).

[0094] The mass spectrum data of compound P-1 are: 189 (8%), 202 (32%), 203 (8%), 204 (100%), 205 (19%), 245 (100%), 246 (30%), 286 (51%), 287 (13%).

[0095] Example 8

[0096] This embodiment provides a method for preparing a terminal olefin-containing tolanthyl liquid crystal compound P-1, and the reaction formula is as follows:

[0097]

[0098] The operation steps are as follows: In a 250ml three-necked flask, 10.3g (50mmol) of compound A-1 (1-methyl-4-[2-(4-methylphenyl)ethynyl]benzene) and 13.44g (120mmol) of potassium tert-butoxide are fully dissolved in tetrahydrofuran, and under a nitrogen environment, the temperature is controlled at -40℃~-30℃, 48ml (2.5M, 120mmol) of n-butyl lithium is added, and the reaction is carried out for 2.5h, and the temperature is controlled at -30℃~-20℃, and 8.4g (110mmol) of compound B-2 (allyl chloride) is added, and the reaction is carried out for 2h; the organic phases are separated, extracted, and combined, washed with water, dried, dissolved through a column, and the solvent is evaporated to obtain 12g of a white solid. The mixture was recrystallized with ethanol, frozen, filtered and dried to obtain 11 g of compound P-1 (1,2-bis(4-butenylphenyl)acetylene) as a white solid (purity: 99.88%, yield: 76.9%).

[0099] The mass spectrum data of compound P-1 are: 189 (8%), 202 (32%), 203 (8%), 204 (100%), 205 (19%), 245 (100%), 246 (30%), 286 (51%), 287 (13%).

[0100] Example 9

[0101] This embodiment provides a method for preparing a terminal olefin-containing tolanthyl liquid crystal compound P-2, and the reaction formula is as follows:

[0102]

[0103] The operation steps are as follows: In a 250ml three-necked flask, 12.1g (50mmol) of compound A-2 (2-fluoro-4-[2-(3-fluoro-4-methylphenyl)ethynyl]-1-methylbenzene) and 11.52g (120mmol) of sodium tert-butoxide are fully dissolved in tetrahydrofuran, and under a nitrogen environment, the temperature is controlled at -40°C to -30°C, 92ml (1.3M, 120mmol) of sec-butyl lithium is added, and the reaction is carried out for 1h, and the temperature is controlled at -30°C to -20°C, 13.32g (110mmol) of compound B-3 (allyl bromide) is added, and the reaction is carried out for 40min; the organic phases are separated, extracted, and combined, washed with water, dried, dissolved through a column, and the solvent is evaporated to obtain 13.5g of a white solid. Recrystallize with ethanol, freeze, filter and dry to obtain 12.5 g of compound P-2 (1-(but-3-en-1-yl)-4-{2-[4-(but-3-en-1-yl)-3-fluorophenyl]ethynyl}-2-fluorobenzene) as a white solid (purity: 99.92%, yield: 77.6%).

[0104] The mass spectrum data of compound P-2 are: 220 (10%), 225 (8%), 238 (30%), 239 (8%), 240 (95%), 241 (17%), 281 (100%), 282 (30%), 322 (48%), 323 (11%).

[0105] Example 10

[0106] This embodiment provides a method for preparing a terminal olefin-containing tolanthyl liquid crystal compound P-2, and the reaction formula is as follows:

[0107]

[0108] The operation steps are as follows: In a 250ml three-necked flask, 12.1g (50mmol) of compound A-2 (2-fluoro-4-[2-(3-fluoro-4-methylphenyl)ethynyl]-1-methylbenzene) and 11.52g (120mmol) of sodium tert-butoxide are fully dissolved in tetrahydrofuran, and under a nitrogen environment, the temperature is controlled at -40℃~-30℃, 92ml (1.3M, 120mmol) of sec-butyl lithium is added, and the reaction is carried out for 1h, and the temperature is controlled at -30℃~-20℃, 13.32g (110mmol) of compound B-3 (allyl bromide) is added, and the reaction is carried out for 3h; liquid separation, extraction, and combination of organic phases are carried out, washed with water, dried, dissolved through a column, and the solvent is evaporated to obtain 14g of a white solid. Recrystallize with ethanol, freeze, filter and dry to obtain 13.2 g of compound P-2 (1-(but-3-en-1-yl)-4-{2-[4-(but-3-en-1-yl)-3-fluorophenyl]ethynyl}-2-fluorobenzene) as a white solid (purity: 99.89%, yield: 82%).

[0109] The mass spectrum data of compound P-2 are: 220 (10%), 225 (8%), 238 (30%), 239 (8%), 240 (95%), 241 (17%), 281 (100%), 282 (30%), 322 (48%), 323 (11%).

[0110] Embodiment 11

[0111] This embodiment provides a method for preparing a terminal olefin-containing tolanthyl liquid crystal compound P-2, and the reaction formula is as follows:

[0112]

[0113] The operation steps are as follows: In a 250ml three-necked flask, 12.1g (50mmol) of compound A-2 (2-fluoro-4-[2-(3-fluoro-4-methylphenyl)ethynyl]-1-methylbenzene) and 11.52g (120mmol) of sodium tert-butoxide are fully dissolved in tetrahydrofuran, and under a nitrogen environment, the temperature is controlled at -60℃~-55℃, 92ml (1.3M, 120mmol) of sec-butyl lithium is added, and the reaction is carried out for 1h, and the temperature is controlled at -30℃~-20℃, and 13.32g (110mmol) of compound B-3 (allyl bromide) is added, and the reaction is carried out for 1h; liquid separation, extraction, and combination of organic phases are carried out, washed with water, dried, dissolved through a column, and the solvent is evaporated to obtain 11g of a white solid. Recrystallize with ethanol, freeze, filter and dry to obtain 10.5 g of compound P-2 (1-(but-3-en-1-yl)-4-{2-[4-(but-3-en-1-yl)-3-fluorophenyl]ethynyl}-2-fluorobenzene) as a white solid (purity: 99.86%, yield: 73.4%).

[0114] The mass spectrum data of compound P-2 are: 220 (10%), 225 (8%), 238 (30%), 239 (8%), 240 (95%), 241 (17%), 281 (100%), 282 (30%), 322 (48%), 323 (11%).

[0115] Example 12

[0116] This embodiment provides a method for preparing a terminal olefin-containing tolanthyl liquid crystal compound P-3, and the reaction formula is as follows:

[0117]

[0118] The operation steps are as follows: In a 250ml three-necked flask, 15.76g (40mmol) of compound A-9 (2-fluoro-4-(4-{2-[4-(3-fluoro-4-methylphenyl)phenyl]ethynyl}phenyl)-1-methylbenzene) is fully dissolved in 2-methyltetrahydrofuran, under a nitrogen environment, the temperature is controlled at -15°C to -10°C, 70ml (1.3M, 91mmol) of tert-butyl lithium is added, and the reaction is carried out for 2h, the temperature is controlled at -30°C to -20°C, 10.64g (88mmol) of compound B-2 (allyl bromide) is added, and the reaction is carried out for 3h; the organic phases are separated, extracted, and combined, washed with water, dried, dissolved through a column, and the solvent is evaporated to obtain 17g of a white solid. Recrystallize with toluene:ethanol (1:3), freeze, filter and dry to obtain 14.7 g of compound P-3 (1-(but-3-en-1-yl)-4-[4-(2-{4-[4-(but-3-en-1-yl)-3-fluorophenyl]phenyl}ethynyl)phenyl]-2-fluorobenzene) as a white solid (purity: 99.68%, yield 77.4%).

[0119] The mass spectrum data of compound P-3 are: 272 (10%), 277 (7%), 390 (28%), 391 (8%), 392 (92%), 393 (16%), 433 (100%), 434 (30%), 474 (43%), 475 (10%).

[0120] It can be seen from the above examples that the method provided by the present invention can significantly improve the reaction purity and yield by selecting specific solvents, organic lithium reagents and reaction conditions.

[0121] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the preparation method of the diphenylacetylene liquid crystal compound containing terminal olefins of the present invention, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0122] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0123] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. A method for preparing a tolanyl liquid crystal compound containing terminal olefins, characterized in that: The preparation method comprises the following steps: (1) fully dissolving the compound of formula A in an organic solvent; (2) Under a protective gas environment, the temperature is controlled at -80°C to 0°C, an organic lithium reagent is added, and the reaction is carried out for 0.2 to 6 hours; (3) Control the temperature at -80°C to 10°C, add the compound of general formula B, and react for 0.5 to 10 hours to obtain the compound of general formula P. The reaction is as follows: Among them, the ring and ring Each independently expresses ring and ring Each independently expresses R1 represents -F, -Cl, -Br or -I; n1 and n2 each independently represent an integer from 0 to 1; n3 and n3' each independently represent an integer of 1-3.

2. The preparation method according to claim 1, characterized in that: The preparation method comprises the following steps: (1) fully dissolving the compound of formula A and an organic base in an organic solvent; (2) Under a protective gas environment, the temperature is controlled at -80°C to 0°C, an organic lithium reagent is added, and the reaction is carried out for 0.2 to 6 hours; (3) Control the temperature at -80°C to 10°C, add the compound of general formula B, and react for 0.5 to 10 hours to obtain the compound of general formula P.

3. The preparation method according to claim 1 or 2, characterized in that: The organic solvent is selected from diethyl ether, methyl tert-butyl ether, ethylene glycol dimethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran or a combination thereof; the protective gas is selected from nitrogen or argon.

4. The preparation method according to claim 1 or 2, characterized in that: The compound of formula A is selected from the group consisting of the following compounds: as well as The compound of formula B is selected from the group consisting of the following compounds: as well as 5. The preparation method according to claim 1 or 2, characterized in that: The molar ratio of the compound of the general formula A to the compound of the general formula B is 1:2 to 1:

4.

6. The preparation method according to claim 1 or 2, characterized in that: The reaction temperature of step (2) is -70°C to -10°C; the reaction temperature of step (3) is -50°C to -10°C.

7. The preparation method according to claim 1 or 2, characterized in that: The reaction time of step (2) is 0.4 to 2.5 hours; the reaction time of step (3) is 0.6 to 3 hours.

8. The preparation method according to claim 2, characterized in that: The organic base is selected from potassium tert-butoxide, sodium tert-butoxide or a combination thereof.

9. The preparation method according to claim 1 or 2, characterized in that: The organic lithium reagent is selected from n-butyl lithium, sec-butyl lithium, tert-butyl lithium or a combination thereof; the molar ratio of the compound of the general formula A to the organic lithium reagent is 1:2 to 1:

4.

10. The preparation method according to claim 2, characterized in that: The molar ratio of the organic lithium reagent to the organic base is 1:0.9 to 1:1.5.

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