JP2822102B2 - Alkenyl compounds - Google Patents

Description

The present invention relates to a compound useful as a liquid crystal material. More specifically, the present invention relates to a liquid crystal compound having an alkenyl group at a molecular terminal.

(Prior art and its problems) Display elements using liquid crystals are widely used in watches, calculators, and the like. These liquid crystal display elements utilize optical anisotropy and dielectric anisotropy of a liquid crystal material. The liquid crystal phase includes a nematic liquid crystal phase, a smectic liquid crystal phase, and a cholesteric liquid crystal phase. Among them, a liquid crystal phase using a nematic liquid crystal is most widely used. There are display elements such as TN (twisted nematic) type, DS (dynamic scattering) type, guest, host type, DAP type, etc., for the electro-optic effect applied to liquid crystal display. Preferably, the liquid crystal material exhibits a liquid crystal phase in a temperature range as wide as possible in nature. Many liquid crystal compounds are already known, but at present there is no single liquid crystal material that satisfies such conditions, and several types of liquid crystal materials or even non-liquid crystal materials are mixed for practical use. . These substances are required to be stable to moisture, light, heat, air and the like. A mixture of the above-mentioned liquid crystal materials and the like, that is, a liquid crystal composition has a small optical anisotropy value and a low viscosity, and the threshold voltage is relatively small compared to the dielectric anisotropy value (abbreviated as Δε). It is desired that it be small enough. Further, the liquid crystal material is required to be compatible with many existing liquid crystal materials in a temperature range as wide as possible. An object of the present invention is to provide a compound which preferably acts on a liquid crystal obtained when mixed with an existing liquid crystal material in a liquid crystal phase range, an optical anisotropy value, a dielectric anisotropy value or a viscosity. .

(Means for Solving the Problems) The present invention provides a compound represented by the general formula (I) (Wherein, X represents a fluorine or chlorine atom, m represents 1 or 2, n represents an integer of 0 to 4, R represents a hydrogen atom or a linear or branched alkyl group having 1 to 7 carbon atoms) The present invention relates to a novel liquid crystal compound represented by the formula:

The present invention includes compounds represented by the following formulas Ia to Ih. In these formulas, n and R have the meaning described above.

Among these, the compound represented by the formula Ia, Ib, Ie or If greatly contributes to Δε when used as a liquid crystal material. Among them, the compound represented by the formula Ia or Ie is preferable from the viewpoint of compatibility with many existing liquid crystal materials.

The compound of the present invention wherein R in the formula (I) is an alkyl group is in a trans form in terms of the steric structure of the double bond to which R is bonded. The alkyl group for R has 1 carbon atom
To 7 are preferable, and a methyl group, an ethyl group and a propyl group are more preferable.

The compounds of the present invention have relatively low viscosities and have a large positive dielectric anisotropy and good elastic constants and elastic constant ratios.

The compound of the present invention is mixed with one or more of the existing liquid crystal compounds to form a liquid crystal mixture.

As the liquid crystal compound that can be mixed with the compound of the present invention,
Known compounds represented by the following formulas (i) to (xxxiii) can be mentioned.

In the formulas (i) to (xxxiii), X is Y represents -CN, a halogen atom, R ¹ or -OR ¹
And R ¹ represents an alkyl group.

The compound of the present invention has the general formula (II) (Wherein X represents a fluorine or salt carbon atom, m represents 1 or 2, and n represents an integer of 0 to 4) and an aldehyde derivative represented by the following general formula (III): R ′ ₃ P ＝ CH— R (III) (wherein R represents a hydrogen atom or a linear or branched alkyl group having 1 to 7 carbon atoms, and R ′ represents an alkyl group, an aryl group or an aralkyl group) Obtained by a Wittig reaction in which a compound is reacted.

The compound of the present invention also relates to an aldehyde derivative represented by the formula (II) and a sulfone derivative represented by the general formula RCH ₂ SO ₂ R ′ (IV) (wherein R and R ′ have the same meanings as described above). The reaction can be carried out in the presence of a base, and the resulting product can be stereoselectively synthesized by reduction treatment.

The compounds of the invention formed by the reaction of the general formulas (II) and (III) are generally obtained as a mixture of their stereoisomers, which can be separated, for example, by column chromatography. If necessary, the stereoisomer of the compound of the present invention can be converted to the compound of the present invention by a method known per se. Further, the compound of the present invention is obtained by brominating a mixture of the compound of the present invention and its stereoisomer or only the stereoisomer of the compound of the present invention with triphenylphosphine-bromine and reducing the obtained halide. It can be converted to a mixture containing a significant proportion.

The reaction between the compound represented by the general formula (II) and the compound represented by the general formula (III) in the production method of the compound of the present invention can be carried out by a method known per se. For example, the corresponding phosphonium salt and potassium t- as a suitable base
Compound (III) obtained by reacting butoxide, sodium methoxide, sodium hydride, n-butyllithium, lithium diisopropylamide, pyridine, triethylamine and the like can be used. This reaction and the subsequent reaction with compound (II) are generally performed in an organic solvent. As a solvent that can be used in this reaction, any solvent that does not inhibit the reaction may be used. It can be used as a single solvent or a mixed solvent. The reaction temperature can be selected from the range from -50 degrees to the boiling point of the solvent used. The reaction is preferably carried out at -30 ° C to room temperature. However, when the concentration of the raw materials in the reaction mixture is high, the reaction should be carried out at a low temperature, and -30 ° C to 0 ° C is preferred.

In the method for producing the compound of the present invention, the reaction between the compound represented by the general formula (II) and the compound represented by the general formula (IV) is carried out by first performing an addition reaction in the presence of a base, and then hydrolyzing to convert to an alcohol form. Further, an elimination reaction is carried out under reducing conditions. Examples of the base used in the first addition reaction include potassium t-butoxide, sodium methoxide, sodium hydride, n-butyllithium, lithium diisopropylamide, pyridine, and triethylamine. In general, the reaction is preferably performed in a solvent. The solvent used may be inert to the reaction, and may be, for example, diethyl ether, tetrahydrofuran, dioxane, benzene, toluene, hexane, methylene chloride, chloroform, dimethyl sulfoxide, dimethylformamide. And so on. The reaction temperature can be selected from the range from -50 degrees to the boiling point of the solvent used. The reaction is preferably performed at −30 ° C. to room temperature, but should be performed at a low temperature when the raw material concentration in the reaction mixture is high,
-30 to 0 degrees is preferred. The hydrolysis can then be carried out under normal quench conditions, for example by treatment with water. The alcohol produced by this reaction is reacted under reducing conditions such as sodium amalgam, lithium amalgam, sodium-tellurium alloy, zinc-hydrochloric acid, zinc-acetic acid, tin-hydrochloric acid, or electrolytic reduction to obtain the present invention. Can be converted to a compound. Solvents used in the elimination reaction include water, methanol, ethanol, 1,2
-Dimethoxyethane, diethyl ether, tetrahydrofuran, dioxane, benzene, toluene, hexane,
Methylene chloride, chloroform, dimethyl sulfoxide,
Dimethylformamide and the like can be mentioned. When performing electrolytic reduction, a general electrolytic apparatus can be used, but for example, mercury, lead, or platinum can be used as an electrode,
If necessary, a suitable amount of a supporting electrolyte such as sodium iodide or a quaternary ammonium salt can be added. The reaction temperature is selected from the range from -20 ° C to the boiling point of the solvent used.

The compound represented by the general formula (II), which is a starting material for synthesizing the compound of the present invention, can be produced, for example, by the following several methods.

(Wherein, m, n and R ′ have the same meanings as described above;
m 'represents m-1, Yn represents one or a plurality of substituents which are easily derivable to the types of substitution shown in formula (I) or those substituents. That is, a compound of the general formula (II, m = 1 or 2) can be easily synthesized by combining generally known methods using a phosphorus ylide or benzaldehyde derivative which can be easily prepared from the corresponding benzyl halide as a starting material. You can also.

(Examples) Hereinafter, the compounds of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 1- [trans-4- {2 '-(4 "-cyano-3")
-Fluorophenyl) ethyl {cyclohexyl] -2-
Synthesis of propene (m-1, n = 1, R = H) (1) A suspension of methoxymethyltriphenylphosphonium chloride (7.52 g) in ether (30 ml) was stirred under a stream of nitrogen gas and cooled to 0 ° C. While adding potassium t-butoxide (2.69 g) in small portions. After stirring the reaction solution at 5 ° C. for 20 minutes, a solution of 4- {2 ′-(4 ″ -cyano-3 ″ -fluorophenyl) ethyl} cyclohexanone (4.54 g) in ether (150 ml) is added dropwise. The reaction mixture is warmed to room temperature and stirred for another 2 hours. After completion of the reaction, an aqueous solution of sodium hydrogen carbonate (20 ml) was added to the crude solution, and the mixture was extracted with ether (20 ml × 3). The organic layer was washed with water, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. A yellow oil (4.43 g) obtained was dissolved in tetrahydrofuran (50 ml), and 1N hydrochloric acid (15 ml) was added. Stir for hours. After completion of the reaction, the crude liquid was neutralized with sodium hydrogen carbonate, and then extracted with ether (20 ml × 3). The organic layer was washed with water, dried over anhydrous magnesium sulfate and concentrated under reduced pressure to give 4- {2 '-(4 "-cyano-3" -fluorophenyl) ethyl} cyclohexanecarbaldehyde yellow oil ( 4.01 g).

(2) A suspension of methoxymethyltriphenylphosphonium chloride (6.38 g) in ether (30 ml) was stirred under a stream of nitrogen gas, and while cooling to 0 ° C., potassium t-butoxide (2.25 g) was added in small portions. After stirring the reaction solution at 5 ° C. for 20 minutes, a solution of 4- {2 ′-(4 ″ -cyano-3 ″ -fluorophenyl) ethyl} cyclohexanecarbaldehyde (4.01 g) in ether (20 ml) is added dropwise. The reaction mixture is warmed to room temperature and stirred for another 2 hours. After completion of the reaction, an aqueous solution of sodium hydrogen carbonate (20 ml) was added to the crude solution, and the mixture was extracted with ether (20 ml × 3). The organic layer was washed with water, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The obtained yellow oil (4.12 g) was dissolved in tetrahydrofuran (50 ml), and 1N hydrochloric acid (15 ml) was added, followed by stirring for 2 hours. I do. After completion of the reaction, the crude liquid was neutralized with sodium hydrogen carbonate, and then extracted with ether (20 ml × 3). The organic layer was washed with water, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure to give 4- {2 '-(4 "-cyano-3" -fluorophenyl) ethyl} cyclohexylacetaldehyde as a yellow oil (3.98). g). The cis-trans mixture was recrystallized from a mixed solvent of ether and pentane to isolate only the trans form (2.01 g).

(3) Methyl triphenyl phosphonium bromide (6.25 g) was added to diisopropyl ether (100 m
Suspend in l) and cool to -10 degrees. Potassium t in suspension
-Butoxide (1.85 g) is added quickly and then at room temperature for 30 minutes.
Stir for a minute. After cooling the suspension to 0 ° C, trans-4-
A solution of {2 '-(4 "-cyano-3" -fluorophenyl) ethyl} cyclohexylacetaldehyde (3.00 g) in diisopropyl ether (50 ml) is added, and the mixture is further stirred at room temperature for 1 hour. The obtained reaction mixture is water (200 ml)
And extracted with diethyl ether (100 ml × 3).
The organic layer is washed with water, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain a pale yellow oil. This was dissolved in ethyl acetate (30 ml), pentane (50 ml) was added, the mixture was cooled to -10 ° C, and the precipitated solid was separated. The obtained solution was concentrated and then recrystallized from an ether-pentane mixed solvent system to give 1- [trans-4- {2'-
(4 ″ -Cyano-3 ″ -fluorophenyl) ethyl {cyclohexyl] -2-propene (2.79 g) was obtained.

 The same compound is repeated to produce the next compound.

2-methyl-9- [trans-4- {2 '-(4 "-cyano-3" -fluorophenyl) ethyl} cyclohexyl] -4E-nonene 6- [trans-4- {2'-(4 " -Cyano-3 ″-
Chlorophenyl) ethyl {cyclohexyl] -1-hexene 7- [trans-4- {2 '-(4 "-cyano-3"-
Chlorophenyl) ethyl {cyclohexyl] -2E-heptene 8- [trans-4- {2 '-(4 "-cyano-3"-)
Chlorophenyl) ethyl {cyclohexyl] -3E-octene 5- [trans-4- {2 '-(4 "-cyano-3"-
Chlorophenyl) ethyl {cyclohexyl] -1-pentene 6- [trans-4- {2 '-(4 "-cyano-3"-
Chlorophenyl) ethyl {cyclohexyl] -2E-hexene 7- [trans-4- {2 '-(4 "-cyano-3"-
Chlorophenyl) ethyl {cyclohexyl] -3E-heptene 8- [trans-4- {2 '-(4 "-cyano-3"-)
Chlorophenyl) ethyl {cyclohexyl] -4E-octene 4- [trans-4- {2 '-(4 "-cyano-3"-
Chlorophenyl) ethyl {cyclohexyl] -1-butene 5- [trans-4- {2 '-(4 "-cyano-3"-
Chlorophenyl) ethyl {cyclohexyl] -2E-pentene 1- [trans-4- {2 '-(4 "-cyano-3"-
Chlorophenyl) ethyl {cyclohexyl] -3E-hexene 1- [trans-4- {2 '-(4 "-cyano-3"-
Chlorophenyl) ethyl {cyclohexyl] -3E-heptene 1- [trans-4- {2 '-(4 "-cyano-3"-)
Chlorophenyl) ethyl {cyclohexyl] -3E-octene 1- [trans-4- {2 '-(4 "-cyano-3"-)
Chlorophenyl) ethyl {cyclohexyl] -3E-nonene 5-methyl-1- [trans-4- {2 '-(4 "-cyano-3" -chlorophenyl) ethyl} cyclohexyl] -3E-nonene 6,7-dimethyl- 1- [trans-4- {2 ′-(4 ″)
-Cyano-3 "-chlorophenyl) ethyl {cyclohexyl] -3E-octene 1- [trans-4- {2 '-(4" -cyano-2 "-
Fluorophenyl) ethyl {cyclohexyl] -2E-hexene 1- [trans-4- {2 '-(4 "-cyano-3"-
Fluorophenyl) ethyl {cyclohexyl] -2E-butene 1- [trans-4- {2 '-(4 "-cyano-3"-
Chlorophenyl) ethyl {cyclohexyl] -2E-pentene 1- [trans-4- {2 '-(4 "-cyan-2"-
Chlorophenyl) ethyl {cyclohexyl] -2E-octene 7-methyl-1- [trans-4- {2 '-(4 "-cyano-3" -fluorophenyl) ethyl} cyclohexyl] -2E-nonene 6,7- Dimethyl-9- [trans-4- {2 '-(4 "
-Cyano-2 "-fluorophenyl) ethyl {cyclohexyl] -2E-nonene 1- [trans-4- {2 '-(4" -cyano-3 "-
Fluorophenyl) ethyl {cyclohexyl] -1E-pentene 1- [trans-4- {2 '-(4 "-cyano-3"-
Fluorophenyl) ethyl {cyclohexyl] -1E-heptene 1- [trans-4- {2 '-(4 "-cyano-2"-
Fluorophenyl) ethyl {cyclohexyl] -1E-hexene 1- [trans-4- {2 '-(4 "-cyano-3"-
Fluorophenyl) ethyl {cyclohexyl] -1E-butene 4-methyl-1- [trans-4- {2 '-(4 "-cyano-3" -chlorophenyl) ethyl} cyclohexyl] -1E-pentene 1- [trans -4- {2 '-(4 "-cyano-2"-
Chlorophenyl) ethyl {cyclohexyl] -1E-octene 7-methyl-1- [trans-4- {2 '-(4 "-cyano-3" -fluorophenyl) ethyl} cyclohexyl] -1E-nonene Example 21 − [Trans-4- [trans-4 ′-｛2 ″-(4
-Cyano-3-chlorophenyl) ethyl {cyclohexyl] cyclohexyl] -1E-pentene (m = 2, n
= 0, R = n-propyl) Methyl n-butylsulfone (1.36g) is dissolved in anhydrous tetrahydrofuran (10ml) and cooled to -20 ° C. To this solution is added n-butyllithium (1N-hexane solution, 10 ml)
Is slowly added dropwise, and after the completion of the addition, the liquid temperature is raised to 0 ° C., and the mixture is stirred for 15 minutes. A solution of trans-4- [trans-4 '-{2 "-(4-cyano-3-chlorophenyl) ethyl} cyclohexyl] cyclohexylaldehyde (3.57 g) in tetrahydrofuran (15 ml) is added dropwise to the reaction mixture. The solution is warmed to room temperature, stirred for 1 hour, water (20 ml) is added to the resulting mixture, extracted with ethyl acetate (10 ml × 3), the organic layer is washed with water, dried over anhydrous magnesium sulfate and reduced in pressure. Concentrate down to give a pale yellow oil, which is dissolved in anhydrous 1,2-dimethoxyethane (10 ml) and freshly prepared sodium amalgam (40%, 8 ml) is added. After stirring, the mixture was allowed to stand, and the ether layer and mercury were separated by decantation, dried, and concentrated under reduced pressure. 1- [trans-4-
[Trans-4 '-{2 "-(4-cyano-3-chlorophenyl) ethyl} cyclohexyl] cyclohexyl] -1E-pentene (3.12 g) was obtained.

 The following compounds are prepared in a similar manner.

1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-2-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -1E-hexene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-chlorophenyl) ethyl {cyclohexyl] cyclohexyl] -1E-heptene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-2-chlorophenyl) ethyl {cyclohexyl] cyclohexyl] -1E-octene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -1E-nonene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -5-methyl-1E-hexene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -4-ethyl-1E-heptene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -5,7-dimethyl-1E-octene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -3,5-dimethyl-4-ethyl-1E-nonene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -2E-hexene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -2E-heptene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -2E-octene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -2E-nonene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -5-methyl-2E-hexene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -4-ethyl-2E-heptene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -5,7-dimethyl-2E-octene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -3,5-dimethyl-4-ethyl-2E-nonene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -3E-hexene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -3E-heptene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -3E-octene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -3E-nonene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -5-methyl-3E-hexene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -4-ethyl-3E-heptene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -5,7-dimethyl-3E-octene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -3,5-dimethyl-4-ethyl-3E-nonene 6- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -2E-hexene 7- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -3E-heptene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -4E-octene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -4E-nonene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -4E-decene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -5,7-dimethyl-4E-octene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -4,8-dimethyl-4E-nonene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -6-methyl-4E-decene 6- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -1-hexene 7- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -2E-heptene 8- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -3E-octene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -5E-nonene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -5E-decene 8- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -2-methyl-3E-octene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -6,7-dimethyl-5E-nonene 1- [trans-4- [trans-4 '-{2 "-(4
-Cyano-3-fluorophenyl) ethyl {cyclohexyl] cyclohexyl] -6-methyl-5E-decene (Effect of the Invention) The present invention provides a compound useful as a component of a liquid crystal material used for a display device. Addition of the compound achieves expansion of the liquid crystal phase temperature range of the liquid crystal material, an increase in dielectric anisotropy or a decrease in the operating threshold voltage of the obtained display element.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C07C 255/50 C09K 19/30 CA (STN) CAOLD (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] 1. The compound of the general formula (I) (In the formula, X represents a fluorine or chlorine atom, m represents 1 or 2, n represents an integer of 0 to 4, and R represents a hydrogen atom or a linear or branched chain having 1 to 7 carbon atoms. Which represents an alkyl group). (2) at least one liquid crystal compound, and a compound represented by the general formula: (In the formula, X represents a fluorine or chlorine atom, m represents 1 or 2, n represents an integer of 0 to 4, and R represents a hydrogen atom or a linear or branched chain having 1 to 7 carbon atoms. A liquid crystalline mixture comprising at least one compound represented by the formula: