CN110437846B - Fluorine substituted benzoxazole liquid crystal compound containing acetylene bond and preparation method thereof - Google Patents
Fluorine substituted benzoxazole liquid crystal compound containing acetylene bond and preparation method thereof Download PDFInfo
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Abstract
The invention discloses a fluorine substituted benzoxazole liquid crystal compound containing an alkyne bond and a preparation method thereof, belonging to the technical field of materials. The structural formula of the compound is
Wherein R represents C5～C12M represents hydrogen, methyl or nitro. The compound is prepared from 2, 3-difluoro-p-bromobenzaldehyde, 2-methyl-3-butine-2-alcohol, 1-iodine-4- (alkoxy) benzene and aminophenol which are used as raw materials through reactions such as Sonogashira coupling, nucleophilic addition, ring closure and the like. The compound has high birefringence, and the preparation method has simple steps and high yield, and can be applied to liquid crystal photoelectric devices to improve the response speed of the liquid crystal photoelectric devices.
Description
Technical Field
The invention belongs to the technical field of materials, and particularly relates to a fluorine substituted benzoxazole liquid crystal compound containing an acetylene bond and a preparation method thereof.
Background
The liquid crystal material is widely applied to the display fields of tablet personal computers, mobile phones, notebook computers, high-definition televisions and the like, and the non-display fields of optical modulators, laser beam deflection, adaptive optics and the like. The liquid crystal photoelectric device has the advantages of low driving voltage, large phase modulation amount, light weight, low power consumption and the like.
The liquid crystal material is a key core material of the liquid crystal photoelectric device, and the performance optimization of the liquid crystal photoelectric device is mainly realized by regulating and controlling the structure and components of the liquid crystal material. In recent years, fast response is an important development direction in which liquid crystal electro-optical devices have been pursued. In order to improve the response speed of the liquid crystal photoelectric device, on one hand, a liquid crystal compound with low viscosity can be adopted, and the viscosity of the liquid crystal compound has a direct relation with the response time of the liquid crystal device, namely, the lower the viscosity of the liquid crystal material is, the smaller the response time of the liquid crystal device is, and the faster the response speed is; on the other hand, the cell thickness of the liquid crystal device can be reduced, the lower the cell thickness of the liquid crystal device is, the faster the response speed is, and the use of the liquid crystal material with large optical anisotropy (delta n) can effectively reduce the cell thickness of the liquid crystal device in practical application. Therefore, the large delta n liquid crystal is a key material for realizing quick response of the liquid crystal photoelectric device.
The structure of the liquid crystal compound is generally constructed by taking a benzene ring, a cyclohexyl group, an aromatic heterocyclic ring and the like as rigid skeletons, and the conjugation length of liquid crystal molecules can be increased by introducing acetylene bonds, increasing the benzene ring, introducing a cyano group or an isothiocyanato group and the like, so that the delta n of the liquid crystal compound is further improved. At present, although a plurality of Δ n liquid crystal materials exist, the Δ n is not large enough and the variety is not large enough, so that the application of the Δ n liquid crystal materials in liquid crystal photoelectric devices is limited. In particular, there are very few large Δ n aromatic heterocyclic liquid crystal compounds that can be used as liquid crystal electro-optical devices.
Disclosure of Invention
The invention aims to provide a fluorine substituted benzoxazole liquid crystal compound containing an alkyne bond and having a larger birefringence, and a preparation method for the compound, which has simple process steps and high yield.
Aiming at the purposes, the fluorine substituted benzoxazole liquid crystal compound containing acetylene bonds has the following structural formula:
wherein R represents C5～C12M represents H, CH3、NO2Any one of them.
The preparation method of the fluorine substituted benzoxazole liquid crystal compound containing the acetylene bond comprises the following steps:
1. preparation of 4- (4- (1, 3-dioxolan-2-yl) -2, 3-difluorophenyl) -2-methylbut-3-yn-2-ol
Adding 2, 3-difluoro-p-bromobenzaldehyde, p-toluenesulfonic acid and ethylene glycol into trichloromethane, reacting for 6-8 h at 50-70 ℃, removing the solvent by reduced pressure evaporation, then adding 2-methyl-3-butyn-2-ol, cuprous iodide, triphenylphosphine, tetrakis (triphenylphosphine) palladium and triethylamine under the protection of nitrogen, reacting for 8-10 h at 80-90 ℃, separating and purifying to obtain 4- (4- (1, 3-dioxolan-2-yl) -2, 3-difluorophenyl) -2-methylbut-3-yn-2-ol, wherein the reaction equation is as follows:
2. preparation of 2- (4-ethynyl-2, 3-difluorophenyl) -1, 3-dioxolane
Refluxing 4- (4- (1, 3-dioxolane-2-yl) -2, 3-difluorophenyl) -2-methylbut-3-yne-2-ol and sodium hydroxide in toluene for 4-6 h, separating and purifying to obtain 2- (4-ethynyl-2, 3-difluorophenyl) -1, 3-dioxolane, wherein the reaction equation is as follows:
3. preparation of 2- (2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) phenyl) -1, 3-dioxolane
Adding 2- (4-ethynyl-2, 3-difluorophenyl) -1, 3-dioxolane, 1-iodo-4- (alkoxy) benzene shown in formula I, cuprous iodide, triphenylphosphine and tetrakis (triphenylphosphine) palladium into triethylamine, reacting for 8-10 h at 60-80 ℃ under the protection of nitrogen, and after the reaction is finished, separating and purifying to obtain 2- (2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) phenyl) -1, 3-dioxolane, wherein the reaction equation is as follows:
in the formula I, R represents C5～C12Linear alkyl group of (1).
4. Preparation of 2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) benzaldehyde
Adding 2- (2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) phenyl) -1, 3-dioxolane and formic acid into tetrahydrofuran, reacting for 5-6 h at 50-70 ℃, separating and purifying after the reaction is finished to obtain 2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) benzaldehyde, wherein the reaction equation is as follows:
5. preparation of 2- ((2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) benzylidene) amino) phenol
Adding 2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) benzaldehyde and aminophenol shown in a formula II into ethanol, stirring and refluxing for 4-6 h, distilling under reduced pressure to remove a solvent, and recrystallizing to obtain 2- ((2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) benzylidene) amino) phenol, wherein the reaction equation is as follows:
in formula II, M represents H, CH3、NO2Any one of them.
6. Preparation of fluorine substituted benzoxazole liquid crystal compound containing acetylene bond
Adding 2- ((2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) benzylidene) amino) phenol and dichlorodicyanoquinone (DDQ) into chloroform, performing reflux reaction for 4-6 h, stopping the reaction, separating and purifying to obtain a target compound, namely a fluorine substituted benzoxazole liquid crystal compound containing an acetylene bond, wherein the reaction equation is as follows:
in the step 1, 2, 3-difluoro-p-bromobenzaldehyde, p-toluenesulfonic acid and ethylene glycol are preferably used, the molar ratio of 2, 3-difluoro-p-bromobenzaldehyde to 2-methyl-3-butyn-2-ol to cuprous iodide to the molar ratio of 2, 3-difluoro-p-bromobenzaldehyde to 2-methyl-3-butyn-2-ol to tetrakis (triphenylphosphine) palladium is preferably 1: 0.4-1: 0.02-0.05: 0.04-0.1: 0.008-0.01.
In the step 2, the molar ratio of 4- (4- (1, 3-dioxolan-2-yl) -2, 3-difluorophenyl) -2-methylbut-3-yn-2-ol to sodium hydroxide is preferably 1:6 to 6.5.
In the step 3, the molar ratio of 2- (4-ethynyl-2, 3-difluorophenyl) -1, 3-dioxolane to 1-iodo-4- (alkoxy) benzene, cuprous iodide, triphenylphosphine, and tetrakis (triphenylphosphine) palladium is preferably 1:0.8 to 1.2:0.004 to 0.008:0.01 to 0.015:0.02 to 0.05.
In the step 4, the molar ratio of 2- (2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) phenyl) -1, 3-dioxolane to formic acid is preferably 1:170 to 175.
In the step 5, the molar ratio of 2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) benzaldehyde to aminophenol is preferably 1: 1.1-1.5.
In the step 6, the molar ratio of 2- ((2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) benzylidene) amino) phenol to dichlorodicyanobenzoquinone is preferably 1:1.1 to 1.5.
The invention has the following beneficial effects:
the liquid crystal compound is prepared by taking 2, 3-difluoro-p-bromobenzaldehyde, 2-methyl-3-butine-2-alcohol, 1-iodine-4- (alkoxy) benzene and aminophenol as raw materials through reactions such as Sonogashira coupling, nucleophilic addition, ring closing and the like, has a heterocyclic liquid crystal mesophase type, also has higher birefringence and a wide nematic phase interval, and the preparation method has simple steps and high yield, and can be applied to liquid crystal photoelectric devices.
Drawings
FIG. 1 is a DSC curve (rise/fall rate of 5 ℃ C./min) of the liquid crystal compound obtained in example 1.
FIG. 2 is a photograph (200X) of a POM obtained in example 1, wherein the temperature of the liquid crystal compound was raised to 173.6 ℃.
FIG. 3 is a photograph (200X) of a POM in which the temperature of the liquid crystal compound obtained in example 1 was lowered to 167.2 ℃.
Detailed Description
The invention will be further described in detail with reference to the following figures and examples, but the scope of the invention is not limited to these examples.
Example 1
1. Preparation of 4- (4- (1, 3-dioxolan-2-yl) -2, 3-difluorophenyl) -2-methylbut-3-yn-2-ol
10g (49.6mmol) of 2, 3-difluoro-p-bromobenzaldehyde, 2.2g (12.7mmol) of p-toluenesulfonic acid and 70g (1120.0mmol) of ethylene glycol are added into a 250mL single-neck bottle provided with a condenser and a stirrer, 100mL of trichloromethane dried by a molecular sieve is added into the bottle, the reaction is stopped after stirring for 6h in a constant-temperature oil bath at 60 ℃, the solvent is evaporated under reduced pressure, 2.01g (23.8mmol) of 2-methyl-3-butyn-2-ol, 0.2g (1.0mmol) of cuprous iodide and 0.6g (2.2mmol) of triphenylphosphine are added into the bottle, 80mL of triethylamine is added into the bottle as a reaction solvent, the bottle is heated and is protected by nitrogen, after the reaction is carried out for 1h, 0.5g (0.43mmol) of tetratriphenylphosphine palladium is rapidly added under the protection of nitrogen, and the reaction is stopped after the reaction is continued for 8 h. After the reaction is finished, diluting the reaction system with water, extracting with dichloromethane, separating an organic phase, repeatedly extracting an aqueous phase with dichloromethane, combining the organic phases, washing the obtained organic phase with a saturated ammonium chloride aqueous solution for three times, drying the organic phase with anhydrous magnesium sulfate, distilling the solvent under reduced pressure, adding 7g of silica gel to prepare a sample, and performing column chromatography (eluent is a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 30: 1) to obtain a yellow oily liquid 4- (4- (1, 3-dioxolan-2-yl) -2, 3-difluorophenyl) -2-methylbut-3-yn-2-ol, wherein the yield is 44%, and the reaction equation is as follows:
2. preparation of 2- (4-ethynyl-2, 3-difluorophenyl) -1, 3-dioxolane
4g (14.9mmol) of 4- (4- (1, 3-dioxolan-2-yl) -2, 3-difluorophenyl) -2-methylbut-3-yn-2-ol, 3.57g (89.4mmol) of sodium hydroxide and 80mL of toluene were placed in a 250mL single-neck flask equipped with a stirrer and a condenser in this order, reacting the reaction system at 80 ℃ for 4h, extracting the reaction solution by using dichloromethane and water after the reaction is finished, combining organic phases, distilling under reduced pressure to remove the solvent, adding 8g of silica gel for preparing a sample, and performing column chromatography (eluent is a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 10: 1) to obtain a light yellow oily liquid 2- (4-ethynyl-2, 3-difluorophenyl) -1, 3-dioxolane, wherein the yield is 67%, and the reaction equation is as follows:
3. preparation of 2- (2, 3-difluoro-4- ((4- (pentyloxy) phenyl) ethynyl) phenyl) -1, 3-dioxolane 2.1g (10mmol) of 2- (4-ethynyl-2, 3-difluorophenyl) -1, 3-dioxolane, 2.7g (9mmol) of 1-iodo-4- (pentyloxy) benzene, 0.09g (0.04mmol) of cuprous iodide, 0.26g (0.1mmol) of triphenylphosphine were sequentially charged into a 250Ml three-necked flask equipped with a stirrer and a condenser, heated in a 70 ℃ constant temperature oil bath and purged with nitrogen, and after 1 hour of reaction, 0.23g (0.2mmol) of palladium tetratriphenylphosphine was rapidly added under nitrogen protection, and the reaction was stopped after 8 hours of further reaction. After the reaction is finished, diluting the reaction system with water, extracting with dichloromethane, separating an organic phase, repeatedly extracting an aqueous phase with dichloromethane, combining the organic phases, washing the obtained organic phase with a saturated ammonium chloride solution for three times, drying the organic phase with anhydrous magnesium sulfate, distilling the solvent under reduced pressure to remove the solvent, adding 7g of silica gel to prepare a sample, and performing column chromatography (eluent is a mixed solution of petroleum ether and ethyl acetate in a volume ratio of 30: 1) to obtain a light yellow solid 2- (2, 3-difluoro-4- ((4- (pentyloxy) phenyl) ethynyl) phenyl) -1, 3-dioxolane, wherein the yield is 55%, and the reaction equation is as follows:
4. preparation of 2, 3-difluoro-4- ((4- (pentyloxy) phenyl) ethynyl) benzaldehyde
2.5g (6.7mmol) of 2- (2, 3-difluoro-4- ((4- (pentyloxy) phenyl) ethynyl) phenyl) -1, 3-dioxolane, 54g (1166mmol) of formic acid and 80mL of tetrahydrofuran were put in a 250mL single-neck flask equipped with a stirrer and a condenser in this order, and the mixture was heated in a constant temperature oil bath at 60 ℃ for 6 hours to conduct a reaction. After the reaction is finished, extracting a reaction solution by using dichloromethane and water, carrying out rotary evaporation and concentration to obtain a white solid, adding absolute ethyl alcohol for recrystallization to obtain a white solid 2, 3-difluoro-4- ((4- (pentyloxy) phenyl) ethynyl) benzaldehyde, wherein the yield is 81%, and the reaction equation is as follows:
5. preparation of 2- ((2, 3-difluoro-4- ((4- (pentyloxy) phenyl) ethynyl) benzylidene) amino) phenol
In a 100mL single-neck flask equipped with a stirrer and a condenser were charged 0.4g (1.3mmol) of 2, 3-difluoro-4- ((4- (pentyloxy) phenyl) ethynyl) benzaldehyde, 0.17g (1.5mmol) of o-aminophenol, and 40mL of absolute ethanol, and the mixture was stirred at 80 ℃ and refluxed for 6 hours until the reaction was complete. After cooling to room temperature, yellow needle crystals precipitated and were filtered off with a buchner funnel, a yellow solid, 2- ((2, 3-difluoro-4- ((4- (pentyloxy) phenyl) ethynyl) benzylidene) amino) phenol, was obtained in 84% yield, the reaction equation was as follows:
6. preparation of 2- (2, 3-difluoro-4- ((4- (pentyloxy) phenyl) ethynyl) phenyl) benzoxazole liquid crystal 0.2g (0.5mmol) of 2- ((2, 3-difluoro-4- ((4- (pentyloxy) phenyl) ethynyl) benzylidene) amino) phenol, 0.13g (0.58mmol) of dichlorodicyanoquinone (DDQ), and 40mL of chloroform were added to a 100mL single-neck flask equipped with a stirrer and a condenser, heated to reflux with a constant temperature oil bath, and reacted for 5h to completion. When the reaction liquid is cooled to room temperature, extracting the reaction liquid by using dichloromethane and water, combining organic phases, removing the solvent by rotation, adding 2g of silica gel for sample preparation, and performing column chromatography (eluent is a mixed liquid of petroleum ether and ethyl acetate in a volume ratio of 30: 1) to obtain white solid 2- (2, 3-difluoro-4- ((4- (pentyloxy) phenyl) ethynyl) phenyl) benzoxazole, wherein the yield is 92%, and the reaction equation is as follows:
spectral data for the product are as follows:
IR(KBr)v(cm-1)：2943,2864,2202,1686,1607,1564,1467,1406,1248,1085,1012,830,665.
1H-NMR(400MHz,CDCl3,TMS)δ(ppm)＝7.99-7.93(m,1H),7.86-7.83(m 1H),7.64-7.60(m,1H),7.53-7.48(m,2H),7.43-7.35(m,3H),6.97-6.83(m,2H),4.07-3.91(q，3JH-H＝6.57Hz,2H),1.86-1.72(m,2H),1.51-1.31(m,4H),0.99-0.84(t,3JH-H＝6.88Hz,3H).
MS (MALDI-TOF) m/z: theoretical 417.46, found 418.21.
Example 2
In step 5 of this example, an equimolar amount of 2-amino-4-methylphenol was used instead of the o-aminophenol in step 5 of example 1, and the other steps were the same as in example 1 to give 2- (2, 3-difluoro-4- ((4- (pentyloxy) phenyl) ethynyl) phenyl) -5-methylbenzoxazole having the following structural formula in a yield of 89%.
Spectral data for the product are as follows:
IR(KBr)v(cm-1)：2949,2870,2196,1686,1601,1552,1503,1406,1248,1085,1012,830,665.
1H-NMR(400MHz,CDCl3,TMS)δ(ppm)＝7.98-7.89(m,1H),7.62-7.59(m 1H),7.64-7.60(m,1H),7.53-7.46(m,3H),7.39-7.34(m,1H),7.23-7.19(dd,3JH-H＝8.27Hz,4JH-H＝1.68Hz 1H),6.96-6.81(m,2H),4.03-3.92(q,3JH-H＝6.65Hz,2H),2.49(s,3H),1.89-1.72(m,2H),1.51-1.32(m,4H),1.01-0.88(t,3JH-H＝7.04Hz,3H).
MS (MALDI-TOF) m/z: theoretical 431.48, found 432.22.
Example 3
In step 5 of this example, an equimolar amount of 2-amino-4-nitrophenol was used in place of the o-aminophenol in step 5 of example 1, and the other steps were the same as in example 1 to give 2- (2, 3-difluoro-4- ((4- (pentyloxy) phenyl) ethynyl) phenyl) -5-nitrobenzoxazole having the following structural formula in a yield of 67%.
Spectral data for the product are as follows:
IR(KBr)v(cm-1)：2943,2852,2202,1601,1552,1473,1346,1158,1085,1012,830,726,665.
1H-NMR(400MHz,CDCl3,TMS)δ(ppm)＝8.73-8.01(d,J4 H-H＝2.11Hz,1H),8.40-8.34(dd,J3 H-H＝9.13Hz,J4 H-H＝2.28Hz,1H),8.01-7.95(m 1H),7.77-7.71(d,J3 H-H＝9.26Hz,1H),7.54-7.48(m,2H),7.45-7.38(m,1H),6.93-6.86(m,2H),4.07-3.94(q，3JH-H＝6.81Hz,2H),1.86-1.73(m,2H),1.51-1.32(m,4H),0.99-0.84(t,3JH-H＝6.98Hz,3H).
MS (MALDI-TOF) m/z: theoretical 462.45, found 463.23.
Example 4
In step 3 of this example, 1-iodo-4- (pentyloxy) benzene in step 3 of example 1 was replaced with equimolar 1-iodo-4- (octyloxy) benzene, and the other steps were the same as in example 1 to give 2- (2, 3-difluoro-4- ((4- (octyloxy) phenyl) ethynyl) phenyl) benzoxazole having the following structural formula in 89% yield.
Spectral data for the product are as follows:
IR(KBr)v(cm-1)：2932,2863,2205,1603,1512,1239,1158,1096,999,830,744,665.
1H-NMR(400MHz,CDCl3,TMS)δ(ppm)＝8.00-7.92(m,1H),7.86-7.81(m 1H),7.66-7.59(m,1H),7.53-7.48(m,2H,overlap),7.44-7.35(m,3H),6.92-6.85(m,2H),4.02-3.89(q，3JH-H＝6.58Hz,2H),1.88-1.73(m,2H),1.50-1.41(m,2H),1.36-1.22(m,8H),0.93-0.82(t,3JH-H＝6.85Hz,3H).
MS (MALDI-TOF) m/z: theoretical 459.54, found 460.25.
Example 5
In step 3 of this example, 1-iodo-4- (pentyloxy) benzene in step 3 of example 2 was replaced with equimolar 1-iodo-4- (dodecyloxy) benzene, and the other steps were the same as in example 2 to give 2- (2, 3-difluoro-4- ((4- (dodecyloxy) phenyl) ethynyl) phenyl) -5-methylbenzoxazole having the following structural formula in a yield of 91%.
Spectral data for the product are as follows:
IR(KBr)v(cm-1)：2931,2852,2208,1601,1556,1449,1401,1248,1158,1103,1085,1024,799,635.
1H-NMR(400MHz,CDCl3,TMS)δ(ppm)＝7.98-7.89(m,1H),7.62-7.59(m 1H),7.64-7.60(m,1H),7.53-7.46(m,3H),7.39-7.34(m,1H),7.23-7.19(d,d,3JH-H＝8.27Hz,1H),6.96-6.81(dd,2H),4.00-3.94(q,3JH-H＝6.56Hz,2H),2.48(s,3H),1.84-1.73(m,2H),1.51-1.40(m,2H),1.39-1.28(m,16H),0.95-0.85(t,3JH-H＝7.10Hz,3H).
MS (MALDI-TOF) m/z: theoretical 529.67, found 530.21.
The optical anisotropy and the thermal properties of the liquid crystal compounds prepared in the above examples 1 to 5 were tested to obtain the birefringence, the phase transition temperature and the phase transition enthalpy. The birefringence was obtained as a theoretical value by Gaussian09 software; the experimental value can also be obtained through Abbe refractometer test; the phase transition temperature and enthalpy of phase change are determined by differential scanning calorimeter measurements. The results are shown in tables 1 and 2.
TABLE 1 Birefringence
TABLE 2 phase transition temperature and enthalpy of phase transition
Note: cr in the table represents a crystalline phase; n represents a nematic phase; i represents isotropy.
As can be seen from Table 1, the Liquid crystal compounds of the present invention (experimental value Δ n. gtoreq.0.457) and the large birefringence Liquid crystal compounds in the literature (Liquid Crystals,2017, 44:14-15,2184-2191) are described
(experimental value Δ n is 0.305), Δ n is significantly improved, and it is further confirmed that the liquid crystal compound of the present invention has excellent optical anisotropy.
As can be seen from Table 2, the compounds of the present invention have a wide nematic phase interval.
As can be seen from the DSC curve (rising and falling temperature rate of 5 ℃/min) in FIG. 1 and the POM photographs (200X) in FIGS. 2 and 3, the compound of the present invention has a nematic liquid crystal texture and a liquid crystal phase state at both rising and falling temperatures.
Claims (7)
1. A preparation method of a fluorine substituted benzoxazole liquid crystal compound containing an alkyne bond is disclosed, wherein the structural formula of the compound is as follows:
wherein R represents C5～C12M represents H, CH3、NO2Any one of the above, characterized in that it consists of the following steps:
(1) preparation of 4- (4- (1, 3-dioxolan-2-yl) -2, 3-difluorophenyl) -2-methylbut-3-yn-2-ol
Adding 2, 3-difluoro-p-bromobenzaldehyde, p-toluenesulfonic acid and ethylene glycol into trichloromethane, reacting for 6-8 h at 50-70 ℃, removing the solvent by reduced pressure evaporation, then adding 2-methyl-3-butyn-2-ol, cuprous iodide, triphenylphosphine, tetrakis (triphenylphosphine) palladium and triethylamine under the protection of nitrogen, reacting for 8-10 h at 80-90 ℃, separating and purifying to obtain 4- (4- (1, 3-dioxolan-2-yl) -2, 3-difluorophenyl) -2-methylbut-3-yn-2-ol, wherein the reaction equation is as follows:
(2) preparation of 2- (4-ethynyl-2, 3-difluorophenyl) -1, 3-dioxolane
Refluxing 4- (4- (1, 3-dioxolane-2-yl) -2, 3-difluorophenyl) -2-methylbut-3-yne-2-ol and sodium hydroxide in toluene for 4-6 h, separating and purifying to obtain 2- (4-ethynyl-2, 3-difluorophenyl) -1, 3-dioxolane, wherein the reaction equation is as follows:
(3) preparation of 2- (2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) phenyl) -1, 3-dioxolane
Adding 2- (4-ethynyl-2, 3-difluorophenyl) -1, 3-dioxolane, 1-iodo-4- (alkoxy) benzene shown in formula I, cuprous iodide, triphenylphosphine and tetrakis (triphenylphosphine) palladium into triethylamine, reacting for 8-10 h at 60-80 ℃ under the protection of nitrogen, and after the reaction is finished, separating and purifying to obtain 2- (2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) phenyl) -1, 3-dioxolane, wherein the reaction equation is as follows:
in the formula I, R represents C5～C12The linear alkyl group of (1);
(4) preparation of 2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) benzaldehyde
Adding 2- (2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) phenyl) -1, 3-dioxolane and formic acid into tetrahydrofuran, reacting for 5-6 h at 50-70 ℃, separating and purifying after the reaction is finished to obtain 2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) benzaldehyde, wherein the reaction equation is as follows:
(5) preparation of 2- ((2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) benzylidene) amino) phenol
Adding 2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) benzaldehyde and aminophenol shown in a formula II into ethanol, stirring and refluxing for 4-6 h, distilling under reduced pressure to remove a solvent, and recrystallizing to obtain 2- ((2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) benzylidene) amino) phenol, wherein the reaction equation is as follows:
in formula II, M represents H, CH3、NO2Any one of them;
(6) preparation of fluorine substituted benzoxazole liquid crystal compound containing acetylene bond
Adding 2- ((2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) benzylidene) amino) phenol and dichlorodicyanobenzoquinone into trichloromethane, carrying out reflux reaction for 4-6 h, stopping the reaction, and separating and purifying to obtain the fluorine substituted benzoxazole liquid crystal compound containing the acetylenic bond.
2. The method for preparing a fluorine substituted benzoxazole liquid crystal compound containing an acetylene bond according to claim 1, characterized in that: in the step (1), the molar ratio of the 2, 3-difluoro-p-bromobenzaldehyde to the p-toluenesulfonic acid to the ethylene glycol is 4: 1-1.5: 80-90, and the molar ratio of the 2, 3-difluoro-p-bromobenzaldehyde to the 2-methyl-3-butyn-2-ol, cuprous iodide, triphenylphosphine and tetrakis (triphenylphosphine) palladium is 1: 0.4-1: 0.02-0.05: 0.04-0.1: 0.008-0.01.
3. The method for preparing a fluorine substituted benzoxazole liquid crystal compound containing an acetylene bond according to claim 1, characterized in that: in the step (2), the molar ratio of the 4- (4- (1, 3-dioxolan-2-yl) -2, 3-difluorophenyl) -2-methylbut-3-yn-2-ol to the sodium hydroxide is 1: 6-6.5.
4. The method for preparing a fluorine substituted benzoxazole liquid crystal compound containing an acetylene bond according to claim 1, characterized in that: in the step (3), the molar ratio of the 2- (4-ethynyl-2, 3-difluorophenyl) -1, 3-dioxolane to the 1-iodo-4- (alkoxy) benzene, cuprous iodide, triphenylphosphine and tetrakis (triphenylphosphine) palladium is 1: 0.8-1.2: 0.004-0.008: 0.01-0.015: 0.02-0.05.
5. The method for preparing a fluorine substituted benzoxazole liquid crystal compound containing an acetylene bond according to claim 1, characterized in that: in the step (4), the molar ratio of the 2- (2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) phenyl) -1, 3-dioxolane to formic acid is 1: 170-175.
6. The method for preparing a fluorine substituted benzoxazole liquid crystal compound containing an acetylene bond according to claim 1, characterized in that: in the step (5), the molar ratio of the 2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) benzaldehyde to aminophenol is 1: 1.1-1.5.
7. The method for preparing a fluorine substituted benzoxazole liquid crystal compound containing an acetylene bond according to claim 1, characterized in that: in the step (6), the molar ratio of the 2- ((2, 3-difluoro-4- ((4- (alkoxy) phenyl) ethynyl) benzylidene) amino) phenol to the dichlorodicyanobenzoquinone is 1: 1.1-1.5.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101209998A (en) * | 2006-12-31 | 2008-07-02 | 盐城鼎龙化工有限公司 | Method for synthesizing 5-amide-6-hydroxy-2-(4-carboxylphenyl)benzoxazole |
| JP2012031143A (en) * | 2010-06-30 | 2012-02-16 | Adeka Corp | New compound, photoelectric conversion material, and photoelectric conversion element |
| CN103058947A (en) * | 2012-12-24 | 2013-04-24 | 石家庄诚志永华显示材料有限公司 | Liquid crystal compound containing benzoxazole and difluoromethylenedioxy bridged linkage and preparation method and application thereof |
| CN103304506A (en) * | 2013-06-07 | 2013-09-18 | 陕西师范大学 | Method for preparing fluorine-containing benzoxazole liquid crystal compound |
| CN104745200A (en) * | 2015-03-24 | 2015-07-01 | 陕西师范大学 | Liquid crystal compound containing acetal ring and preparation method of liquid crystal compound |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH504505A (en) * | 1966-08-15 | 1971-03-15 | Ciba Geigy Ag | Use of new tolane derivatives as optical brightening agents outside the textile industry |
| JPS584778A (en) * | 1981-06-29 | 1983-01-11 | Mitsubishi Chem Ind Ltd | Benzoxazole derivative |
| JP3060313B2 (en) * | 1990-06-08 | 2000-07-10 | キヤノン株式会社 | Liquid crystal compound, liquid crystal composition containing the same, and liquid crystal device using the same |
| CN1155585C (en) * | 2001-12-19 | 2004-06-30 | 中国医学科学院医药生物技术研究所 | 3,5-substituted oxazolidinone derivative and its preparing process and application |
| CN1241917C (en) * | 2002-11-29 | 2006-02-15 | 石家庄永生华清液晶有限公司 | 2,5-substituted benzoxazole derivative, preparing process and uses thereof |
| ZA200601978B (en) * | 2003-09-05 | 2007-05-30 | Neurogen Corp | Heteroaryl fused pyridines, pyrazines and pyrimidines as CRF1 receptor ligands |
| JP5611538B2 (en) * | 2008-05-16 | 2014-10-22 | 株式会社半導体エネルギー研究所 | Benzoxazole derivative, and light-emitting element, light-emitting device, lighting device, and electronic device using benzoxazole derivative |
| CN101830894B (en) * | 2010-06-01 | 2013-05-29 | 上海交通大学 | Benzo[d]oxazole compounds and preparation method thereof |
-
2019
- 2019-08-30 CN CN201910813709.6A patent/CN110437846B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101209998A (en) * | 2006-12-31 | 2008-07-02 | 盐城鼎龙化工有限公司 | Method for synthesizing 5-amide-6-hydroxy-2-(4-carboxylphenyl)benzoxazole |
| JP2012031143A (en) * | 2010-06-30 | 2012-02-16 | Adeka Corp | New compound, photoelectric conversion material, and photoelectric conversion element |
| CN103058947A (en) * | 2012-12-24 | 2013-04-24 | 石家庄诚志永华显示材料有限公司 | Liquid crystal compound containing benzoxazole and difluoromethylenedioxy bridged linkage and preparation method and application thereof |
| CN103304506A (en) * | 2013-06-07 | 2013-09-18 | 陕西师范大学 | Method for preparing fluorine-containing benzoxazole liquid crystal compound |
| CN104745200A (en) * | 2015-03-24 | 2015-07-01 | 陕西师范大学 | Liquid crystal compound containing acetal ring and preparation method of liquid crystal compound |
Non-Patent Citations (1)
| Title |
|---|
| 含苯并噁唑基的硫桥杯[4]芳烃衍生物的合成及结构;赵邦屯等;《有机化学》;20091015(第10期);第1682-1686页 * |
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