CN1504470A - 3,5-difluoro-4-cyan benzene boric acid ester compound, preparing process thereof and application in liquid crystal composition - Google Patents

Abstract

The invention relates to 3,5- di-fluorine-4-cyano-phenylo boric ester compound, its intermediate 3,5- di-fluorine-4-cyano-phenylo boric acid, process for preparing the compounds and their intermediates, and the use of 3,5- di-fluorine-4-cyano-phenylo boric ester compound in liquid crystal composition. The compound provided by the invention possesses fine stableness and large dielectric anisotropy, and can be used as liquid crystal display material, in particular for liquid crystal composition of TN, STN, TFT, FMLCD or total wave length Cholesteric LCD display.

Description

3,5-two fluoro-4-cyanophenylboronic acid ester compounds, its preparation method and the purposes in liquid-crystal composition thereof

Technical field:

The present invention relates to 3,5-two fluoro-4-cyanophenylboronic acid ester cpds, its intermediate 3,5-two fluoro-4-cyanophenylboronic acids, this compounds and its intermediates preparation and 3, the purposes of 5-two fluoro-4-cyanophenylboronic acid ester cpds in liquid-crystal composition and liquid-crystal display.

Background technology:

Generally, the crystal of organic compound can change transparent liquid into when being heated to fusing point, changes crystal when being cooled to fusing point into.The organism of some special constructions is when undergoing phase transition, between three-dimensional order crystal and unordered liquid, there is the orderly liquid intermediate phase of a series of low-dimensionals, it has the flowability of liquid, has the crystalline anisotropy again, therefore be referred to as mesomorphic phase, compound or mixture with this kind character are referred to as liquid crystal.

Liquid crystal applications is in multiple field, and especially in the flat pannel display field, liquid crystal is widely used, along with the fast development of information industry, the demand of liquid crystal indicator is strengthened year by year, and the requirement of lcd technology, liquid crystal material is also being improved constantly.

According to technique of display and use needs, require to have higher resistivity as the compound or the composition of liquid crystal material, the low viscosity in the low temperature range, big positive dielectric anisotropy (ε), the operating temperature range of broad, lower threshold value, big optical anisotropy, good miscibility.

Up to now, a lot of about the report of liquid crystal material, for example US4551264, DE3209178A1, EP0090183, clear 58-167528, wherein US4551264 discloses the liquid crystalline cpd that contains following structure: N is 1 or 2; R is C _1-5Straight chained alkyl.

Because the huge applications potentiality and the market of liquid crystal material, people are constantly exploring the new liquid crystalline cpd of excellent performance to prepare liquid crystal material and the indicating meters thereof that satisfy different requirements.

Summary of the invention:

The object of the invention provides a kind of intermediate 3,5-two fluoro-4-cyanophenylboronic acids, and it is preparation 3, the intermediate of 5-two fluoro-4-cyanophenylboronic acid ester compounds.

It is a kind of 3 that the object of the invention provides, 5-two fluoro-4-cyanophenylboronic acid ester compounds, and this compound has satisfactory stability and big dielectric anisotropy, can be used as liquid crystalline cpd and is used to prepare various liquid-crystal composition materials and liquid-crystal display.

Another object of the present invention is to provide a kind of intermediate, it is above-mentioned 3 that this intermediate can be used for, the preparation of 5-two fluoro-4-cyanophenylboronic acid ester cpds.

A further object of the present invention provides 3,5-two fluoro-4-cyanophenylboronic acid ester cpds and its intermediate 3, the preparation method of 5-two fluoro-4-cyanophenylboronic acids.

Of the present invention also have a purpose to provide 3, the purposes of 5-two fluoro-4-cyanophenylboronic acid ester cpds in liquid-crystal composition and liquid-crystal display.

The intermediate that the present invention relates to is 3,5-two fluoro-4-cyanophenylboronic acids, and its structure is:

The invention still further relates to 3,5-two fluoro-4-cyanophenylboronic acid ester cpds, its structural formula is shown in (A):

Wherein, R is C ₁-C ₁₃Saturated alkyl, unsaturated alkyl or single at least fluoric alkyl.

A, C are cyclohexyl Phenylene Or the phenyl of single at least fluorine replacement.

M, n are 0 or 1.

X, Y be 0 (singly-bound) or-C ₂H ₄-.Here said 0 or singly-bound, be meant that the group of X or Y both sides directly is connected.

Preferred R is C ₁-C ₁₃Straight chain saturated alkyl, unsaturated straight chained alkyl or single at least fluoric straight chained alkyl, also preferred R is C ₁-C ₇Straight chain saturated alkyl, unsaturated straight chained alkyl or alkyl single or two F generations.More preferably R is CH ₃-, C ₂H ₅-, C ₃H ₇-, C ₄H ₉-, C ₅H ₁₁-, CH ₃CHF-, C ₂H ₅CHF-or CH ₃CHF ₂-.

Preferred m, n are not 0 simultaneously, and one of also preferred m or n are 0, and another is 1, also can m, n all be 0 or all be 1 in some cases certainly.

When A, C are the phenyl of fluorine replacement, the phenyl that preferred single fluorine replaces.

Preferred one of X, Y are 0, or X, Y are 0 simultaneously.Equally here, said 0, be meant that the group of X or Y both sides directly is connected.

The preferred compound of the present invention is exemplified below:

Wherein R is C ₁-C ₁₀Saturated or unsaturated alkyl, single F or two F substituted alkyls.

The preferred compound of the present invention is:

Or

Wherein R is C ₁-C ₁₀Saturated or unsaturated alkyl, single F or two F substituted alkyls.

Of the present invention 3, the preparation method of 5-two fluoro-4-cyanophenylboronic acids is:

1), 3, this benzene of 5-difluoro bromine

In THF, generate Grignard reagent, this grignard reagent solution is added drop-wise in the trimethyl borate at low temperatures reacts, use the HCl acidifying again, through aftertreatment, obtain 3,5-two fluorobenzoic boric acids with the reaction of Mg powder.

2), under Catalyzed by p-Toluenesulfonic Acid, with 3,5-two fluorobenzoic boric acids and glycol reaction obtain 3,5 two fluorobenzoic boric acid second diester through aftertreatment.

3), 3,5-two fluorobenzoic boric acid second diester generate intermediate compound with butyllithium reaction at low temperatures This lithium reagent and I ₂Reaction obtains 3 through aftertreatment, 5-two fluoro-4-iodobenzene boric acid second diester.

4), 3,5-two fluoro-4-iodobenzene boric acid second diester and cuprous cyanide back flow reaction in solvent, reaction product obtains 3 through acidifying and aftertreatment, 5-two fluoro-4-cyanophenylboronic acids.

Wherein in the step 1) grignard reagent solution slowly is added drop-wise under-40 ℃ in the mixed solution of THF of trimethyl borate, and under this temperature, continues reaction.

Aftertreatment in the step 1) is: solvent extraction separatory, washing solvent layer, drying, concentrated.

Step 2) in, with 3,5-two fluorobenzoic boric acids, ethylene glycol and tosic acid divide the water reaction in reflux in toluene.

Step 2) aftertreatment in is: separatory removes the excessive ethylene glycol of sub-cloud, and upper strata liquid concentrates removes toluene, concentrated solution underpressure distillation.

Temperature of reaction in the step 3) is-78 ℃--80 ℃, solvent is among the anhydrous THF;

Aftertreatment in the step 3) is for to rise to room temperature with reaction mixture, and the hydrolysis separatory is used ethyl acetate extraction, and dry, filtration back concentrates to remove desolvates residue sherwood oil recrystallization.

Aftertreatment in the step 4) is: decompression concentrates down and removes DMF, reduces to room temperature, the residue ethyl acetate extraction, and the filtering insolubles, filtrate adds separatory after the aqueous solution of hydrochloric acid acidifying, and organic layer washes with water, and is dry, filter, concentrate except that desolvating.Get 3,5-two fluoro-4-cyanophenylboronic acids.

Reaction process is schematically as follows:

Of the present invention 3, the preparation method of 5-two fluoro-4-cyanophenylboronic acid esters is:

With above-mentioned 3,5-two fluoro-4-cyanophenylboronic acids after reflux is divided water in solvent, obtain compound through aftertreatment under Catalyzed by p-Toluenesulfonic Acid

Wherein aftertreatment is: concentrate to steam and remove toluene, resistates dissolves rear decoloring with the mixing solutions of sherwood oil and ethyl acetate, and the product that obtains is used the sherwood oil recrystallization again.

In R be C ₁-C ₁₃Saturated alkyl, unsaturated alkyl or fluoro-alkyl, A, C are

Or the phenyl that replaces of fluorine, m, n are 0 or 1, X, Y be 0 or-C ₂H ₄-.

In the The compounds of this invention,

Be preferably one of following structure:

R-

Wherein R is preferably C ₁-C ₁₀Saturated or unsaturated alkyl, single F or two F substituted alkyls.

Most preferably be:

R-

Wherein R is CH ₃-, C ₂H ₅-, C ₃H ₇-, C ₄H ₉-, C ₅H ₁₁-, CH ₃CHF-, C ₂H ₅CHF-or CH ₃CHF ₂-.

Of the present invention 3,5-two fluoro-4-cyano group substituted benzene boric acid esters are as liquid crystalline cpd, can form liquid-crystal composition as liquid crystal display material with other liquid crystalline cpds well known in the prior art, be applied to the long courage steroid of TN, STN, TFT, FMLCD or all-wave LCD demonstration liquid-crystal composition especially.When compound of the present invention is used for liquid-crystal composition, its consumption is generally 2-50% (by weight), can make liquid-crystal composition have that chemical stability is good, the ester dissolubility is good, have characteristics such as big positive dielectric anisotropy, degree of birefringence are moderate, therefore be with a wide range of applications.

Of the present invention 3,5-two fluoro-4-cyano group substituted benzene boric acid ester and intermediates 3 thereof, the preparation method of 5-two fluoro-4-cyanophenylboronic acids is simple, yield height, good product purity.

Embodiment:

Embodiment 1

(1) 0.3mol

(GC＞99.5%) reacts in the anhydrous THF of 300ml with the magnesium chips (analytical pure) of 0.3mol, make dun grignard reagent solution, this grignard reagent solution slowly is added drop-wise under-40 ℃ in the mixed solution of 0.4mol trimethyl borate (GC＞99.5%) and the anhydrous THF of 200ml, the dropping process remains at below-40 ℃, drip off back insulation reaction 30 minutes, slowly be raised to room temperature, use 35% hydrochloric acid (analytical pure) of 50ml to add the acidifying of 100ml water again, with 100ml ethyl acetate extraction separatory, upper organic phase washing 3 times, separatory, dry, filter, concentrated steaming desolventizes, and gets 32g yellow 3,5-two fluorobenzoic boric acid solids;

(2) with 3 of 1.5mol, the ethylene glycol (analytical pure) of 5-two fluorobenzoic boric acids, 3mol and 0.03mol tosic acid (analytical pure) in 400ml toluene (GC＞99.5%) about 5 hours of reflux water-dividing to dividing water to finish, separatory removes the excessive ethylene glycol of sub-cloud, upper strata liquid concentrates removes toluene, the concentrated solution underpressure distillation, collect 115～120 ℃/3mmHg cut, 166g is water white 3,5-two fluorobenzoic boric acid second diester liquid;

(3) with 3 of 0.1mol, 5-two fluorobenzoic boric acid second diester are dissolved among the anhydrous THF of 500ml, stir and are cooled to-78 ℃--and between 80 ℃, drip 0.1mol n-Butyl Lithium (BuLi), stirred 0.5 hour, dropping contains 20gI again ₂The 100ml anhydrous THF solution of (analytical pure), continue then to stir 0.5 hour, rise to room temperature, the hydrolysis separatory, use ethyl acetate extraction, the solvent layer of extraction desolvates residue sherwood oil recrystallization with dried over sodium sulfate, filtration, concentrated removing, light yellow 3,5-two fluoro-4-iodobenzene boric acid second diester solids;

(4) with 0.15mol 3,5-two fluoro-4-iodobenzene boric acid second diester and 1.8mol CuCN (analytical pure) back flow reaction 2 hours in the 200ml dry DMF, decompression concentrate down and remove DMF, reduce to room temperature, residue 200ml ethyl acetate extraction, filtering insolubles, filtrate add 10ml hydrochloric acid, 50ml water stirred 20 minutes together, separatory, organic layer washes with water 1 time, abandon water layer, the solvent layer drying, filter, concentrate to remove and desolvate, get the 24g yellow solid, promptly 3,5-two fluoro-4-cyanophenylboronic acids, its fusing point is 112～118 ℃, ultimate analysis: theoretical value: C 45.71%, H 2.74%, N 7.62%, measured value: C 45.25%H 2.96%, N 7.44%.

Embodiment 2

With 0.05mol 3,5-two fluoro-4-cyanophenylboronic acids and 0.05mol 2-ethyl-1,3 propylene glycol are under the 0.003mol Catalyzed by p-Toluenesulfonic Acid, divided water 5 hours in the 50ml reflux in toluene, concentrate and remove toluene, behind the mixing solutions thermosol of excess with 35ml sherwood oil and ethyl acetate (3: 1), with 10g silica gel (analytical pure) decolouring, after filtering, desolventizing, products therefrom once gets the 10g white, needle-shaped crystals with 25ml sherwood oil recrystallization Its fusing point is 70.69～72.22 ℃, and GC 99.5%.

Δ ε=42.5 (extrapotation) MS and ultimate analysis data are as follows:

Molecular formula	Characteristic ion (M/Z +) and abundance (%)
			????C 11H1 2O 2BF 2CN	???251(M +、48.73)、236(1.85)、208(7.8)、179(8.24)、166(20.85)、152 ???(17.63)、119(7.48)、56(100)
????MS ????(M +/Z)	Ultimate analysis
			Theoretical value	Measured value
	????251	???C?57.41％?H?4.82％?N?5.58％			C?57.13％?H?5.05％?N?5.35％

Embodiment 3

Adopt embodiment 1 synthetic 3,5-two fluoro-4-cyanophenylboronic acids, with 0.05mol 3,2-amyl group-1,3 propylene glycol of 5-two fluoro-4-cyanophenylboronic acids and 0.05mol divided water 5 hours in the 50ml reflux in toluene under the 0.003mol Catalyzed by p-Toluenesulfonic Acid, concentrate and remove toluene, behind the excess usefulness 50ml petroleum ether dissolution, with 10g silica gel (analytical pure) decolouring, the mixing solutions recrystallization of products therefrom usefulness 30ml sherwood oil and ethyl acetate (3: 1) once, must about 11.7g white crystals, i.e. compound

Its fusing point is 60.25～63.31 ℃, and mass spectrum and results of elemental analyses are as follows:

????MS ????(M +/Z)	Ultimate analysis
			Theoretical value	Measured value
	????293	?C?61.46％?H?6.19％?N?4.78％			??C?62.55％?H?6.17％?N?4.66％

Embodiment 4

Adopt embodiment 1 synthetic 3,5-two fluoro-4-cyanophenylboronic acids.

With 0.05mol 3, the 2-methyl isophthalic acid of 5-two fluoro-4-cyanophenylboronic acids and 0.04mol, 3 propylene glycol, under the 0.003mol Catalyzed by p-Toluenesulfonic Acid, divided water 5 hours in the 50ml reflux in toluene, concentrate and remove toluene, after the mixing solutions dissolving of excess with 50ml sherwood oil and ethyl acetate (3: 1), with 10g silica gel (analytical pure) decolouring, products therefrom with 30ml sherwood oil recrystallization once gets 7.6l gram, its fusing point: 80.31～80.61 ℃, mass spectrum and results of elemental analyses are as follows:

????MS ????(M +/Z)	Ultimate analysis
			Theoretical value	Measured value
	????237	??C?55.74％?H?4.25％?N?5.91％			????C?55.94％?H?4.35％?N?5.51％

Embodiment 5

Adopt embodiment 1 synthetic 3,5-two fluoro-4-cyanophenylboronic acids.

With 0.05mol 3, the 2-butyl-1 of 5-two fluoro-4-cyanophenylboronic acids and 0.04mol, 3 propylene glycol, under the 0.003mol Catalyzed by p-Toluenesulfonic Acid, divided water 5 hours in the 50ml reflux in toluene, concentrate and remove toluene, after the mixing solutions dissolving of excess with 50ml sherwood oil and ethyl acetate (3: 1), with 10g silica gel (analytical pure) decolouring, products therefrom with 30ml sherwood oil recrystallization once gets

9.90 gram, its fusing point: 75.23～75.78 ℃, mass spectrum and results of elemental analyses are as follows:

????MS ????(M +/Z)	Ultimate analysis
			Theoretical value	Measured value
	????279	???C?60.25％?H?5.78％?N?5.02％			??C?60.13％?H?5.39％?N?4.82％

Embodiment 6

Adopt embodiment 1 synthetic 3,5-two fluoro-4-cyanophenylboronic acids.

With 0.05mol 3,5-two fluoro-4-cyanophenylboronic acids and 0.06mol's

Under the 0.003mol Catalyzed by p-Toluenesulfonic Acid, divided water 5 hours in the 50ml reflux in toluene, concentrate and remove toluene, after excess is used the 50ml petroleum ether dissolution, with 10g silica gel (analytical pure) decolouring, the mixing solutions recrystallization of products therefrom usefulness 30ml sherwood oil and ethyl acetate (3: 1) once gets 14.90 gram, 110.3 ℃ of-112.5 ℃ of mass spectrums of fusing point and results of elemental analyses are as follows:

????MS ????(M +/Z)	Ultimate analysis
			Theoretical value	Measured value
	????361	????C?66.50％?H?7.25％?N?3.88％			???C?66.70％?H?7.35％?N?4.15％

Embodiment 7

Adopt embodiment 1 synthetic 3,5-two fluoro-4-cyanophenylboronic acids.

With 0.05mol 3,5-two fluoro-4-cyanophenylboronic acids and 0.06mol's

Under the 0.003mol Catalyzed by p-Toluenesulfonic Acid, divided water 5 hours in the 50ml reflux in toluene, concentrate and remove toluene, after the mixing solutions dissolving of excess with 50ml sherwood oil and ethyl acetate (3: 1), with 10g silica gel (analytical pure) decolouring, products therefrom with 30ml sherwood oil recrystallization once gets 15.50 gram, 118.3 ℃-120.5 ℃ of fusing points, mass spectrum and results of elemental analyses are as follows:

????MS ????(M +/Z)	Ultimate analysis
			Theoretical value	Measured value
	????375	???C?67.21％?H?7.52％?N?3.73％			??C?67.04％?H?7.12％?N?4.03％

Embodiment 8

Adopt embodiment 1 synthetic 3,5-two fluoro-4-cyanophenylboronic acids.

With 0.05mol 3,5-two fluoro-4-cyanophenylboronic acids and 0.06mol's

Under the 0.003mol Catalyzed by p-Toluenesulfonic Acid, divided water 5 hours in the 50ml reflux in toluene, concentrate and remove toluene, after the mixing solutions dissolving of excess with 50ml sherwood oil and ethyl acetate (3: 1), with 10g silica gel (analytical pure) decolouring, products therefrom with 30ml sherwood oil recrystallization once gets

101.4 ℃-102.6 ℃ of fusing points, mass spectrum and results of elemental analyses are as follows:

????MS ????(M +/Z)	Ultimate analysis
			Theoretical value	Measured value
	????403	???C?68.49％?H?8.00％?N?3.47％			??C?68.45％?H?8.33％?N?3.27％

Embodiment 9

Adopt embodiment 1 synthetic 3,5-two fluoro-4-cyanophenylboronic acids.

With 3 of 0.05mol, 5-two fluoro-4-cyanophenylboronic acids and 0.06mol's Under the 0.003mol Catalyzed by p-Toluenesulfonic Acid, divided water 5 hours in the 50ml reflux in toluene, concentrate and remove toluene, after excess is used the 50ml petroleum ether dissolution, with 10g silica gel (analytical pure) decolouring, the mixing solutions recrystallization of products therefrom usefulness 30ml sherwood oil and ethyl acetate (3: 1) once gets

17.07 gram, 95.6 ℃-96.9 ℃ of fusing points, mass spectrum and results of elemental analyses are as follows:

????MS ????(M +/Z)	Ultimate analysis
			Theoretical value	Measured value
	????379	???C?63.34％?H?6.64％?N?3.69％			??C?62.97％?H?6.85％?N?3.94％

Embodiment 10

Adopt embodiment 1 synthetic 3,5-two fluoro-4-cyanophenylboronic acids.

With 3 of 0.05mol, the C of 5-two fluoro-4-cyanophenylboronic acids and 0.075mol ₂H ₅CHFCH (CH ₂OH) ₂Under the 0.005mol Catalyzed by p-Toluenesulfonic Acid, divided water 5 hours in the 50ml reflux in toluene, concentrate and remove toluene, after the mixing solutions dissolving of excess with 50ml sherwood oil and ethyl acetate (3: 1), with 10g silica gel (analytical pure) decolouring, products therefrom with 30ml sherwood oil recrystallization once gets

12.70 gram, 93.1 ℃-94.4 ℃ of fusing points, mass spectrum and results of elemental analyses are as follows:

????MS ????(M +/Z)	Ultimate analysis
			Theoretical value	Measured value
	????283	???C?55.16％?H?4.63％?N?4.95％			??C?55.18％?H?4.73％?N?4.68％

Embodiment 11

Adopt embodiment 1 synthetic 3,5-two fluoro-4-cyanophenylboronic acids.

With 3 of 0.05mol, 5-two fluoro-4-cyanophenylboronic acids and 0.075mol's

Divided water 5 hours in the 50ml reflux in toluene under the 0.005mol Catalyzed by p-Toluenesulfonic Acid, concentrate and remove toluene, after excess was used the 50ml petroleum ether dissolution, with 10g silica gel (analytical pure) decolouring, products therefrom with 30ml sherwood oil recrystallization once must react, 14.65 gram, 130.4 ℃-131.8 ℃ of fusing points, mass spectrum and results of elemental analyses are as follows:

????MS ????(M +/Z)	Ultimate analysis
			Theoretical value	Measured value
	????333	???C?64.89％?H?6.66％?N?4.20％			??C?64.93％?H?6.76％?N?4.30％

Embodiment 12

Adopt embodiment 1 synthetic 3,5-two fluoro-4-cyanophenylboronic acids.

With 3 of 0.05mol, 5-two fluoro-4-cyanophenylboronic acids and 0.1mol's

Under the 0.005mol Catalyzed by p-Toluenesulfonic Acid, divided water 5 hours in the 50ml reflux in toluene, concentrate and remove toluene, after the mixing solutions dissolving of excess with 50ml sherwood oil and ethyl acetate (3: 1), with 10g silica gel (analytical pure) decolouring, products therefrom with 30ml sherwood oil recrystallization once gets 15.65 gram, 132.3 ℃-133.5 ℃ of fusing points, mass spectrum and ultimate analysis are as follows:

????MS ????(M +/Z)	Ultimate analysis
			Theoretical value	Measured value
	????347	???C?65.73％?H?6.97％?N?4.03％			??C?65.81％?H?7.07％?N?4.12％

Embodiment 13

Adopt embodiment 1 synthetic 3,5-two fluoro-4-cyanophenylboronic acids.

With 0.05mol 3,5-two fluoro-4-cyanophenylboronic acids and 0.1mol's

Under the 0.005mol Catalyzed by p-Toluenesulfonic Acid, divided water 5 hours in the 50ml reflux in toluene, concentrate and remove toluene, after the mixing solutions dissolving of excess with 50ml sherwood oil and ethyl acetate (3: 1), with 10g silica gel (analytical pure) decolouring, products therefrom with 30ml sherwood oil recrystallization once gets 17.00 gram, 128.6 ℃ of-129.9 ℃ of mass spectrums of fusing point and ultimate analysis are as follows:

????MS ????(M +/Z)	Ultimate analysis
			Theoretical value	Measured value
	????375	???C?67.21％?H?7.52％?N?3.73％			??C?67.30％?H?7.48％?N?3.79％

Embodiment 13-17

With reference to the method for embodiment 1, synthetic respectively following formula: compound:

Claims (10)

1,3,5-two fluoro-4-cyanophenylboronic acids, its structure is:

2, a kind of 3,5-two fluoro-4-cyanophenylboronic acid ester cpds, its structural formula is

Wherein, R is C ₁-C ₁₃Saturated alkyl, unsaturated alkyl or single at least fluoric alkyl;

A, C are cyclohexyl

Phenylene

Or the phenyl of single at least fluorine replacement;

M, n are 0 or 1;

X, Y be 0 or-C ₂H ₄-.

3, according to claim 13,5-two fluoro-4-cyanophenylboronic acid ester cpds is characterized in that R is C ₁-C ₁₃Straight chain saturated alkyl, unsaturated straight chained alkyl or single at least fluoric straight chained alkyl, preferred R is C ₁-C ₇Straight chain saturated alkyl, unsaturated straight chained alkyl or alkyl single or two F generations, more preferably R is CH ₃-, C ₂H ₅-, C ₃H ₇-, C ₄H ₉-, C ₅H ₁₁-, CH ₃CHF-, C ₂H ₅CHF-or CH ₃CHF ₂-.

4, according to claim 2 or 3 described 3,5-two fluoro-4-cyanophenylboronic acid ester cpds is characterized in that among m or the n is 0, and another is 1, or m, n are 0 or are 1.

5, according to claim 2 or 3 or 4 described 3,5-two fluoro-4-cyanophenylboronic acid ester cpds is characterized in that A or C are that single fluorine replaces or the phenyl in two F generations.

6, according to claim 2 or 3 or 4 described 3,5-two fluoro-4-cyanophenylboronic acid ester cpds is characterized in that one of X, Y are 0, or X, Y be 0 simultaneously, or X, Y are 1 simultaneously.

7, according to claim 2 or 3 described 3,5-two fluoro-4-cyanophenylboronic acid ester cpds is characterized in that described compound is:

8, the preparation method of the described compound of claim 1 is characterized in that step is as follows:

1), 3,5-difluoro bromobenzene

In THF, generate Grignard reagent, this grignard reagent solution is added drop-wise in the trimethyl borate at low temperatures reacts, use the HCl acidifying again, through aftertreatment, obtain 3,5-two fluorobenzoic boric acids with the reaction of Mg powder.

2), under Catalyzed by p-Toluenesulfonic Acid, with 3,5-two fluorobenzoic boric acids and glycol reaction obtain 3 through aftertreatment, 5-two fluorobenzoic boric acid second diester.

3), 3,5-two fluorobenzoic boric acid second diester generate intermediate compound with butyllithium reaction at low temperatures

This lithium reagent and I ₂Reaction obtains 3 through aftertreatment, 5-two fluoro-4-iodobenzene boric acid second diester.

4), 3,5-two fluoro-4-iodobenzene boric acid second diester and cuprous cyanide back flow reaction in solvent, reaction product obtains 3 through acidifying and aftertreatment, 5-two fluoro-4-cyanophenylboronic acids.

9, the preparation method of any one described compound of claim 2-7 is characterized in that step is as follows:

1), 3,5-difluoro bromobenzene In THF, generate Grignard reagent, this grignard reagent solution is added drop-wise in the trimethyl borate at low temperatures reacts, use the HCl acidifying again, through aftertreatment, obtain 3,5-two fluorobenzoic boric acids with the reaction of Mg powder.

2), under Catalyzed by p-Toluenesulfonic Acid, with 3,5-two fluorobenzoic boric acids and glycol reaction obtain 3 through aftertreatment, 5-two fluorobenzoic boric acid second diester.

3), 3,5-two fluorobenzoic boric acid second diester generate intermediate compound with butyllithium reaction at low temperatures This lithium reagent and I2 reaction obtain 3 through aftertreatment, 5-two fluoro-4-iodobenzene boric acid second diester.

4), 3,5-two fluoro-4-iodobenzene boric acid second diester and cuprous cyanide back flow reaction in solvent, reaction product obtains 3 through acidifying and aftertreatment, 5-two fluoro-4-cyanophenylboronic acids.

With 3,5-two fluoro-4-cyanophenylboronic acids after reflux is divided water in solvent, obtain compound (A) through aftertreatment under Catalyzed by p-Toluenesulfonic Acid.

10, any one described compound application in liquid-crystal composition and liquid-crystal display of claim 2-7.