JP4989904B2 - Ester compound having 1,3-dioxane group, composition containing the compound, retardation plate, and display device - Google Patents

Description

  The present invention relates to an ester compound having a 1,3-dioxane group, a composition containing the compound, a retardation plate, and a display device.

  Liquid crystals (compounds) are widely used in applications such as devices such as displays and optical elements such as retardation plates, and development of new materials according to the purpose is desired. The types of liquid crystals known so far include nematic liquid crystals, cholesteric liquid crystals, smectic liquid crystals, and discotic liquid crystals, and various liquid crystal display elements have been put to practical use by utilizing the electro-optic effect unique to each liquid crystal. . Among these liquid crystals, liquid crystal display elements using nematic liquid crystals are particularly widely used. The display methods include dynamic scattering, birefringence control, guest / host, and twisted nematic (TN). In addition, there are a super twist nematic type (STN type), a super twist birefringence type, etc., and there are a static drive method, a time division drive method, an active matrix drive method, a dual frequency drive method, and the like.

  Liquid crystals must have good chemical stability and stability to heat, and good stability to electric fields and electromagnetic radiation. Furthermore, the liquid crystal material preferably has a low viscosity from the viewpoint of driving speed, and must exhibit a short address time, a low threshold voltage and a large contrast in the cell.

The threshold voltage (Vth) is a function of dielectric anisotropy (Δε) as expressed by the following equation (Mol. Cryst. Liq. Cryst., 12, 57 (1970)).
Vth = π × [K / (ε ₀ × Δε)] ^1/2
In the above equation, K represents an elastic constant, and ε ₀ represents the dielectric constant of vacuum.

  As can be seen from this equation, in order to reduce the threshold voltage, two methods are conceivable: a method of increasing the dielectric anisotropy or a method of decreasing the elastic constant. However, since it is difficult to control the elastic constant with the existing technology, the requirement for a low threshold voltage is addressed by using a material having a large dielectric anisotropy. Therefore, development of liquid crystalline compounds having a large dielectric anisotropy has been actively conducted. For example, 1,3-dioxane derivatives have been disclosed as liquid crystal materials having a positive dielectric anisotropy (for example, patents). Reference 1).

  On the other hand, in recent years, various types of liquid crystal display elements have been developed in order to obtain a high-quality liquid crystal display. In particular, in-plane switching mode (IPS) and vertical alignment mode (VA) systems are attracting attention in developing a wide viewing angle liquid crystal display. The liquid crystal composition used in these liquid crystal display elements is required to have a large Δε and a small elastic constant, and development of a liquid crystal material for satisfying this has been actively conducted.

  As such a liquid crystal material having a large Δε, 2,3-dicyanophenylene is known (for example, see Patent Document 2). As other compounds exhibiting negative dielectric anisotropy, compounds having 2,3-difluoro-1,4-phenylene in the partial structure are generally known (for example, see Non-Patent Document 1). . As a compound for improving the dielectric anisotropy, a compound in which trifluoromethyl is bonded to the side orientation of the compound molecule, a compound in which difluoromethyl is bonded in order to make the negative dielectric anisotropy larger Has been reported (see, for example, Patent Document 3, Non-Patent Document 1, Non-Patent Document 2, and Patent Document 4).

  However, the physical properties required of the compound for the liquid crystal are not only the dielectric anisotropy Δε but also various such as transparency and liquid crystal temperature range. For this reason, there is no liquid crystal compound that can satisfy the required characteristics alone, and a liquid crystal composition prepared from many liquid crystal compounds (see, for example, Patent Document 3) has been used.

Therefore, it is common to mix various compounds in order to control the physical properties of the liquid crystal composition, but as a result, it may be difficult to negatively increase the dielectric anisotropy Δε. Therefore, development of a compound having a large negative dielectric anisotropy Δε is desired.
US Pat. No. 4,313,878 Japanese Patent Publication No.58-22146 International Publication No. 2000-03963 Pamphlet Japanese National Patent Publication No. 10-176167 Angew. Chem. Int. Ed. 2000, 39, 4216-4235 Synlett. 1999, No. 4, 389-396

  An object of the present invention is to provide a compound having a small elastic constant and a large negative dielectric anisotropy Δε, a composition containing the compound, a retardation plate having a small threshold voltage (Vth), and a display device. .

  Means for solving the above problems are as follows. That is, the present invention

<1> A compound represented by the following general formula 1.

In the formula, R ¹ and R ² are, each independently, (including a deuterium atom) hydrogen atom, (including a cycloalkyl group, a bicycloalkyl group, a tricycloalkyl group) A alkyl group, an alkenyl group (cycloalkenyl group includes bicycloalkenyl group), the aryl group, an alkoxy group, an alkenyloxy group, X ¹ to X ¹² each independently include a hydrogen atom (deuterium atom), a halogen atom, an alkyl group (cyclo alkyl group, a bicycloalkyl group, saw including a tricycloalkyl group, including) a fluorinated alkyl group, a sheet anode group, Y ¹ and Y ^2, each independently, a chloro group, fluoro group, or a cyano group And at least one of Y ¹ and Y ² is a cyano group.

<2> The liquid crystal composition you contains at least one compound according to <1>.

< 3 > A retardation plate having at least one optically anisotropic layer on a transparent support,
The optically anisotropic layer is a retardation plate containing at least one of the compounds described in <1 > .

< 4 > A display device having a pair of electrode substrates and a liquid crystal layer disposed between the pair of electrode substrates, wherein the liquid crystal layer contains at least one compound according to <1 > .

  According to the present invention, a compound having a small elastic constant and a large negative dielectric anisotropy Δε, and a composition containing the compound can be provided, and a retardation plate having a small threshold voltage (Vth) and A display device can be provided.

1. Compound Represented by General Formula 1 First, the relationship between the structure of the compound represented by General Formula 1 (hereinafter referred to as “the compound of the present invention” as appropriate) and the dielectric anisotropy Δε will be described.
The dielectric anisotropy (Δε) represents the difference between the dielectric constant in the direction parallel to the molecular orientation direction and the dielectric constant in the vertical direction, and is represented by the following formula.
Dielectric anisotropy (Δε) = ε‖−ε⊥

  In the above formula, ε‖ represents a dielectric constant in a direction parallel to the direction of molecular orientation, and ε⊥ represents a dielectric constant in a perpendicular direction. That is, in order to increase the dielectric anisotropy (Δε), it is effective to increase the polarization in the major axis direction in the molecule of the rod-like liquid crystal compound.

  Here, the compound represented by the general formula 1 of the present invention is as follows.

In General Formula 1, R ¹ and R ² are each independently a hydrogen atom (including a deuterium atom), an alkyl group (including a cycloalkyl group, a bicycloalkyl group, or a tricycloalkyl group), an alkenyl group (cycloalkenyl group). Group, bicycloalkenyl group), aryl group, alkoxy group, alkenyloxy group, and X ^{1 to} X ¹² each independently represent a hydrogen atom (including deuterium atom), a halogen atom, an alkyl group (cycloalkyl). Group, a bicycloalkyl group, a tricycloalkyl group and a fluorinated alkyl group), a cyano group, Y ¹ and Y ² each independently represent a chloro group, a fluoro group, or a cyano group, Y ^At least one of ¹ and Y ² is a cyano group.

  As shown below, the compound represented by the general formula 1 is polarized in the minor axis direction by the carbonyl group of the ester group.

Furthermore, in the phenyl group in the general formula 1, Y ¹ and Y ² are arranged on the same side when the long axis of the compound is the center. Since Y ¹ and Y ² are a chloro group, a fluoro group, or a cyano group, they have a property of attracting electrons. Therefore, the polarization in the minor axis direction is also enhanced by Y ¹ and Y ² .

  Such polarization in the minor axis direction increases the dielectric constant ε⊥ in the minor axis direction, so that the dielectric anisotropy Δε becomes negative and its value increases.

Note that X ¹ and X ² that are symmetrical with respect to Y ¹ and Y ² with respect to the major axis have strong electron withdrawing properties so as not to cancel the electron withdrawing effect of Y ¹ and Y ^2. It is preferably not a substituent.

Hereinafter, the compound represented by Formula 1 will be described in more detail.
The substituents represented by R ¹ , R ² , and X ^{1 to} X ¹² in the general formula 1 are substituents selected from the substituent group W below. In the present invention, among the following substituents, R ¹ and R ² are each independently an alkyl group (including a cycloalkyl group, a bicycloalkyl group, and a tricycloalkyl group), an alkenyl group (a cycloalkenyl group, Represents a bicycloalkenyl group), an aryl group, an alkoxy group, and an alkenyloxy group, and X ^{1 to} X ¹² each independently include a halogen atom, an alkyl group (a cycloalkyl group, a bicycloalkyl group, or a tricycloalkyl group). Represents a cyano group.

(Substituent group W)
Halogen atoms, alkyl groups (including cycloalkyl groups, bicycloalkyl groups, and tricycloalkyl groups), alkenyl groups (including cycloalkenyl groups and bicycloalkenyl groups), alkynyl groups, aryl groups, heterocyclic groups (with heterocyclic groups and Cyano group, hydroxyl group, nitro group, carboxyl group, alkoxy group, aryloxy group, silyloxy group, heterocyclic oxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group Amino group (including anilino group), ammonio group, acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfamoylamino group, alkyl and arylsulfonylamino group, mercapto Alkylthio group, arylthio group, heterocyclic thio group, sulfamoyl group, sulfo group, alkyl and arylsulfinyl group, alkyl and arylsulfonyl group, acyl group, aryloxycarbonyl group, alkoxycarbonyl group, carbamoyl group, aryl and heterocyclic azo Group, imide group, phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, phosphono group, silyl group, hydrazino group, ureido group, boronic acid group (-B (OH) ₂ ), phosphato group ( Examples include —OPO (OH) ₂ ), sulfato groups (—OSO ₃ H), and other known substituents.

  More specifically, the substituent group W represents a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an alkyl group [straight chain, branched, cyclic substituted or unsubstituted alkyl group. They are alkyl groups (preferably alkyl groups having 1 to 30 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, t-butyl, n-octyl, eicosyl, 2-chloroethyl, 2-cyanoethyl, 2-ethylhexyl). A cycloalkyl group (preferably a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, such as cyclohexyl, cyclopentyl, 4-n-dodecylcyclohexyl), a bicycloalkyl group (preferably having 5 to 30 carbon atoms). A substituted or unsubstituted bicycloalkyl group, that is, a monovalent group obtained by removing one hydrogen atom from a bicycloalkane having 5 to 30 carbon atoms, for example, bicyclo [1,2,2] heptan-2-yl, bicyclo [2,2,2] octane-3-yl), a tricyclo structure with more ring structures But also to embrace. An alkyl group (for example, an alkyl group of an alkylthio group) in the substituent described below represents an alkyl group having such a concept, but further includes an alkenyl group and an alkynyl group. ], An alkenyl group [represents a linear, branched or cyclic substituted or unsubstituted alkenyl group. They are alkenyl groups (preferably substituted or unsubstituted alkenyl groups having 2 to 30 carbon atoms, such as vinyl, allyl, prenyl, geranyl, oleyl), cycloalkenyl groups (preferably substituted or unsubstituted 3 to 30 carbon atoms or An unsubstituted cycloalkenyl group, that is, a monovalent group obtained by removing one hydrogen atom of a cycloalkene having 3 to 30 carbon atoms (for example, 2-cyclopenten-1-yl, 2-cyclohexen-1-yl), Bicycloalkenyl group (a substituted or unsubstituted bicycloalkenyl group, preferably a substituted or unsubstituted bicycloalkenyl group having 5 to 30 carbon atoms, that is, a monovalent group obtained by removing one hydrogen atom of a bicycloalkene having one double bond. For example, bicyclo [2,2,1] hept-2-en-1-yl, bicyclo [ It is intended to encompass 2,2] oct-2-en-4-yl). An alkynyl group (preferably a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, such as ethynyl, propargyl, trimethylsilylethynyl group),

An aryl group (preferably a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, such as phenyl, p-tolyl, naphthyl, m-chlorophenyl, o-hexadecanoylaminophenyl), a heterocyclic group (preferably 5 or 6 A monovalent group obtained by removing one hydrogen atom from a substituted or unsubstituted aryl group or non-aromatic heterocyclic compound, and more preferably a 5- or 6-membered aromatic having 3 to 30 carbon atoms For example, 2-furyl, 2-thienyl, 2-pyrimidinyl, 2-benzothiazolyl, and cationic heterocyclic rings such as 1-methyl-2-pyridinio and 1-methyl-2-quinolinio Group), a cyano group, a hydroxyl group, a nitro group, a carboxyl group, an alkoxy group (preferably a C 1-30 substituent or Substituted alkoxy groups such as methoxy, ethoxy, isopropoxy, t-butoxy, n-octyloxy, 2-methoxyethoxy), aryloxy groups (preferably substituted or unsubstituted aryloxy groups having 6 to 30 carbon atoms) For example, phenoxy, 2-methylphenoxy, 4-t-butylphenoxy, 3-nitrophenoxy, 2-tetradecanoylaminophenoxy), a silyloxy group (preferably a silyloxy group having 3 to 20 carbon atoms, for example, trimethylsilyloxy , T-butyldimethylsilyloxy), a heterocyclic oxy group (preferably a substituted or unsubstituted heterocyclic oxy group having 2 to 30 carbon atoms, 1-phenyltetrazol-5-oxy, 2-tetrahydropyranyloxy), An acyloxy group (preferably formyloxy A substituted or unsubstituted alkylcarbonyloxy group having 2 to 30 carbon atoms, a substituted or unsubstituted arylcarbonyloxy group having 6 to 30 carbon atoms, such as formyloxy, acetyloxy, pivaloyloxy, stearoyloxy, benzoyloxy, p -Methoxyphenylcarbonyloxy), a carbamoyloxy group (preferably a substituted or unsubstituted carbamoyloxy group having 1 to 30 carbon atoms, such as N, N-dimethylcarbamoyloxy, N, N-diethylcarbamoyloxy, morpholinocarbonyloxy N, N-di-n-octylaminocarbonyloxy, Nn-octylcarbamoyloxy),

An alkoxycarbonyloxy group (preferably a substituted or unsubstituted alkoxycarbonyloxy group having 2 to 30 carbon atoms such as methoxycarbonyloxy, ethoxycarbonyloxy, t-butoxycarbonyloxy, n-octylcarbonyloxy), aryloxycarbonyloxy group (Preferably a substituted or unsubstituted aryloxycarbonyloxy group having 7 to 30 carbon atoms, such as phenoxycarbonyloxy, p-methoxyphenoxycarbonyloxy, pn-hexadecyloxyphenoxycarbonyloxy), amino group (preferably Is an amino group, a substituted or unsubstituted alkylamino group having 1 to 30 carbon atoms, a substituted or unsubstituted anilino group having 6 to 30 carbon atoms, such as amino, methylamino, dimethylamino, and , N-methyl-anilino, diphenylamino), an ammonio group (preferably an ammonio group, a substituted or unsubstituted alkyl having 1 to 30 carbon atoms, an aryl, a heterocyclic substituted ammonio group such as trimethylammonio, triethyl Ammonio, diphenylmethylammonio), acylamino group (preferably formylamino group, substituted or unsubstituted alkylcarbonylamino group having 1 to 30 carbon atoms, substituted or unsubstituted arylcarbonylamino group having 6 to 30 carbon atoms) , For example, formylamino, acetylamino, pivaloylamino, lauroylamino, benzoylamino, 3,4,5-tri-n-octyloxyphenylcarbonylamino), an aminocarbonylamino group (preferably substituted with 1 to 30 carbon atoms or No placement Aminocarbonylamino such as carbamoylamino, N, N-dimethylaminocarbonylamino, N, N-diethylaminocarbonylamino, morpholinocarbonylamino), alkoxycarbonylamino group (preferably substituted or unsubstituted alkoxy having 2 to 30 carbon atoms) Carbonylamino group, for example, methoxycarbonylamino, ethoxycarbonylamino, t-butoxycarbonylamino, n-octadecyloxycarbonylamino, N-methyl-methoxycarbonylamino),

An aryloxycarbonylamino group (preferably a substituted or unsubstituted aryloxycarbonylamino group having 7 to 30 carbon atoms, such as phenoxycarbonylamino, p-chlorophenoxycarbonylamino, mn-octyloxyphenoxycarbonylamino), Sulfamoylamino group (preferably a substituted or unsubstituted sulfamoylamino group having 0 to 30 carbon atoms, such as sulfamoylamino, N, N-dimethylaminosulfonylamino, Nn-octylaminosulfonylamino ), Alkyl and arylsulfonylamino groups (preferably substituted or unsubstituted alkylsulfonylamino having 1 to 30 carbon atoms, substituted or unsubstituted arylsulfonylamino having 6 to 30 carbon atoms such as methylsulfonylamino, Rusulfonylamino, phenylsulfonylamino, 2,3,5-trichlorophenylsulfonylamino, p-methylphenylsulfonylamino), mercapto group, alkylthio group (preferably a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, For example, methylthio, ethylthio, n-hexadecylthio), arylthio group (preferably substituted or unsubstituted arylthio having 6 to 30 carbon atoms, such as phenylthio, p-chlorophenylthio, m-methoxyphenylthio), heterocyclic thio group (preferably Is a substituted or unsubstituted heterocyclic thio group having 2 to 30 carbon atoms, for example, 2-benzothiazolylthio, 1-phenyltetrazol-5-ylthio), a sulfamoyl group (preferably a substituted or unsubstituted group having 0 to 30 carbon atoms). Substitute sulfamoy Groups such as N-ethylsulfamoyl, N- (3-dodecyloxypropyl) sulfamoyl, N, N-dimethylsulfamoyl, N-acetylsulfamoyl, N-benzoylsulfamoyl, N- (N ′ -Phenylcarbamoyl) sulfamoyl),

A sulfo group, an alkyl and an arylsulfinyl group (preferably a substituted or unsubstituted alkylsulfinyl group having 1 to 30 carbon atoms, a substituted or unsubstituted arylsulfinyl group having 6 to 30 carbon atoms, such as methylsulfinyl, ethylsulfinyl, phenylsulfinyl; P-methylphenylsulfinyl), alkyl and arylsulfonyl groups (preferably substituted or unsubstituted alkylsulfonyl groups having 1 to 30 carbon atoms, substituted or unsubstituted arylsulfonyl groups having 6 to 30 carbon atoms, such as methylsulfonyl, Ethylsulfonyl, phenylsulfonyl, p-methylphenylsulfonyl), acyl group (preferably formyl group, substituted or unsubstituted alkylcarbonyl group having 2 to 30 carbon atoms, substituted or unsubstituted arylcarbonyl group having 7 to 30 carbon atoms) A heterocyclic carbonyl group bonded to a carbonyl group with a substituted or unsubstituted carbon atom having 4 to 30 carbon atoms, such as acetyl, pivaloyl, 2-chloroacetyl, stearoyl, benzoyl, pn-octyloxyphenylcarbonyl, 2-pyridylcarbonyl, 2-furylcarbonyl), an aryloxycarbonyl group (preferably a substituted or unsubstituted aryloxycarbonyl group having 7 to 30 carbon atoms, such as phenoxycarbonyl, o-chlorophenoxycarbonyl, m-nitrophenoxy Carbonyl, pt-butylphenoxycarbonyl), an alkoxycarbonyl group (preferably a substituted or unsubstituted alkoxycarbonyl group having 2 to 30 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, t-butoxycarbonyl) , N-octadecyloxycarbonyl), a carbamoyl group (preferably a substituted or unsubstituted carbamoyl having 1 to 30 carbon atoms, such as carbamoyl, N-methylcarbamoyl, N, N-dimethylcarbamoyl, N, N-di-n -Octylcarbamoyl, N- (methylsulfonyl) carbamoyl), aryl and heterocyclic azo groups (preferably substituted or unsubstituted arylazo groups having 6 to 30 carbon atoms, substituted or unsubstituted heterocyclic azo groups having 3 to 30 carbon atoms) Groups such as phenylazo, p-chlorophenylazo, 5-ethylthio-1,3,4-thiadiazol-2-ylazo), imide groups (preferably N-succinimide, N-phthalimide),

A phosphino group (preferably a substituted or unsubstituted phosphino group having 2 to 30 carbon atoms, such as dimethylphosphino, diphenylphosphino, methylphenoxyphosphino), a phosphinyl group (preferably a substituted or unsubstituted phosphino group having 2 to 30 carbon atoms) An unsubstituted phosphinyl group such as phosphinyl, dioctyloxyphosphinyl, diethoxyphosphinyl), a phosphinyloxy group (preferably a substituted or unsubstituted phosphinyloxy group having 2 to 30 carbon atoms such as , Diphenoxyphosphinyloxy, dioctyloxyphosphinyloxy), a phosphinylamino group (preferably a substituted or unsubstituted phosphinylamino group having 2 to 30 carbon atoms, such as dimethoxyphosphinylamino, Dimethylaminophosphinylamino), phosphor A silyl group (preferably a substituted or unsubstituted silyl group having 3 to 30 carbon atoms, such as trimethylsilyl, t-butyldimethylsilyl, phenyldimethylsilyl), a hydrazino group (preferably a substituted or unsubstituted group having 0 to 30 carbon atoms). A substituted hydrazino group, such as trimethylhydrazino, and a ureido group (preferably a substituted or unsubstituted ureido group having 0 to 30 carbon atoms, such as N, N-dimethylureido).

  Two Ws may be bonded to each other to form a ring. Examples of such a ring include an aryl group, a non-aromatic hydrocarbon ring, and a heterocyclic ring. These can be further combined to form a polycyclic fused ring. For example, benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, fluorene ring, triphenylene ring, naphthacene ring, biphenyl ring, pyrrole ring, furan ring, thiophene ring, imidazole ring, oxazole ring, thiazole ring, pyridine ring, pyrazine ring, pyrimidine Ring, pyridazine ring, indolizine ring, indole ring, benzofuran ring, benzothiophene ring, isobenzofuran ring, quinolidine ring, quinoline ring, phthalazine ring, naphthyridine ring, quinoxaline ring, quinoxazoline ring, isoquinoline ring, carbazole ring, phenanthridine Ring, acridine ring, phenanthroline ring, thianthrene ring, chromene ring, xanthene ring, phenoxathiin ring, phenothiazine ring, phenazine ring

When used as a compound exhibiting liquid crystallinity, R ¹ and R ² in Formula 1 are preferably a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or a heterocyclic group. , A cyano group, a nitro group, a carboxyl group, an alkoxy group, an aryloxy group, and an ester group. Here, the alkyl group, alkenyl group, alkynyl group, and alkoxy group may be linear, branched, or cyclic.

Preferably, R ¹ is a hydrogen atom, a fluorine atom, a chlorine atom, an alkyl group (preferably an alkyl group having 1 to 30 carbon atoms, more preferably 1 to 15 carbon atoms), an alkenyl group (preferably having a carbon number). An alkynyl group (preferably an alkynyl group having 1 to 30 carbon atoms, more preferably an alkynyl group having 1 to 15 carbon atoms), an alkoxy group ( Preferably an alkoxy group having 1 to 30 carbon atoms, more preferably an alkoxy group having 1 to 15 carbon atoms), an aryloxy group (preferably a phenyloxy group), a cyano group, an alkoxycarbonyl group, an ester group, an aryl group. It is.
More preferably, R ¹ is an alkyl group, an alkenyl group, an alkynyl group, or an alkoxy group.

R ² is preferably an alkyl group or an alkoxy group from the viewpoint of not increasing the dielectric constant of the molecular long axis, more preferably an alkyl group having 3 to 20 carbon atoms, and still more preferably an alkyl group having 3 to 12 carbon atoms, Or more preferably, it is a C1-C20, More preferably, it is a C3-C12 alkoxy group. In the case of an alkyl group or alkoxy group having less than 3 carbon atoms, it is difficult to form a liquid crystal, and in the case of an alkyl group or alkoxy group having more than 12 carbon atoms, the melting point becomes too high.

When used as a compound exhibiting liquid crystallinity, X ^{1 to} X ¹² in Formula 1 are preferably a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, or an alkyl group, and more preferably a hydrogen atom. , Deuterium atom, fluorine atom, chlorine atom, cyano group, methyl group, trifluoromethyl group.
Furthermore, X ⁷ is preferably a hydrogen atom, a deuterium atom, a fluorine atom, or a trifluoromethyl group. More preferably, it is a hydrogen atom. When X ⁷ is a fluorine atom or a trifluoromethyl group, polarization in the minor axis direction is promoted in the compound of the present invention.
X ^{2 to} X ⁶ are particularly preferably a hydrogen atom, a deuterium atom, or a methyl group.

The compound represented by the general formula 1 of the present invention is preferably a compound represented by the following general formula 2 from the viewpoint of negatively large Δε. General formula 2 is a case where X ^{7 to} X ¹² in general formula 1 are all hydrogen atoms.

In the above general formula 2, R ¹ , R ² , X ^{1 to} X ⁶ , Y ¹ and Y ² are respectively R ¹ , R ² , X ^{1 to} X ⁶ , Y ¹ and Y ² described in the general formula 1. It is synonymous.

  Specific examples of the compound in the present invention are shown below, but the present invention is not limited thereto.

  By having the above specific structure, the compound of the present invention has a negative dielectric anisotropy Δε and a large value. Negatively large dielectric anisotropy Δε is effective for high-speed response of a device using a liquid crystal composition, and is a physical property necessary for various liquid crystal display systems. Further, it is effective to add to adjust the dielectric anisotropy Δε of the entire liquid crystal composition.

  The compound represented by the general formula 1 of the present invention can be synthesized by a condensation reaction between a benzoic acid having a dioxane ring at the 4-position and a phenol such as phenol. The condensation reaction can be synthesized by using a condensing agent such as dicyclohexylcarbodiimide as shown in Scheme 1 below. Further, as shown in Scheme 2 below, a carboxylic acid can be reacted with a chlorinating agent such as thionyl chloride or phosphorus oxychloride to synthesize an acid chloride, and then a condensation reaction with an alcohol can be performed.

  At this time, the corresponding benzoic acid having a dioxane ring at the 4-position is obtained by subjecting a corresponding 1,3-diol and an aromatic aldehyde to a dehydration condensation reaction in the presence of an acid catalyst, as shown in Scheme 3 below. Can be synthesized. At this time, functional groups weak to acids and bases such as cyano groups and ester groups are decomposed during the synthesis. Therefore, after introducing these substituents, benzoic acids having a dioxane ring at the 4-position are synthesized. It is preferable to introduce.

  The 1,3-dioxane ring into which two groups are introduced has a cis form and a trans form. Among them, a trans form compound exhibits exclusively liquid crystallinity. Therefore, the synthesized 1,3-dioxane compound needs to be purified by column chromatography or recrystallization. If the number of carbon atoms of the substituent bonded to the 1,3-dioxane ring increases, purification by column chromatography becomes difficult. In such a case, a method of purification by recrystallization is preferable.

2. Composition The present invention also provides a composition containing at least one compound represented by the general formula 1.
Such a composition may contain the compound represented by the general formula 1 alone or in combination of two or more thereof, and a liquid crystal composition (preferably a liquid crystal composition for a guest host) by appropriately adding known compounds used for liquid crystals. It may be used as The ratio of the compound of this invention in a composition is not specifically limited, According to a desired physical characteristic, it can mix in arbitrary ratios. When the composition of the present invention is used as a liquid crystal composition, the physical characteristics (optical characteristics and the like) of the liquid crystal composition may be appropriately adjusted using the liquid crystal to be mixed. In the composition of the present invention, usable liquid crystal compounds are not limited, but dual-frequency liquid crystals (nematic and smectic) are preferable.

3. Display Device The compound and composition of the present invention can be used in a liquid crystal display device such as a liquid crystal display. For example, the display device includes a pair of electrode substrates and a liquid crystal layer disposed between the pair of electrode substrates, and the liquid crystal layer includes at least one compound represented by the general formula 1 of the present invention.
Since the display device of the present invention uses a compound represented by the general formula 1 that has a large absolute value of dielectric anisotropy Δε and a negative value, it is suitable as a liquid crystal display with a wide-angle field of view.

As an electrode, what formed the electrode layer on the board | substrate which usually consists of glass or a plastics can be used. Examples of the plastic substrate include acrylic resin, polycarbonate resin, epoxy resin, PES, and PEN.
As the substrate, for example, those described in pages 218 to 231 of “Liquid Crystal Device Handbook” (Japan Society for the Promotion of Science 142nd edition, Nikkan Kogyo Shimbun, 1989) can be used. The electrode layer formed on the substrate is preferably a transparent electrode layer. For example, it can be formed from indium oxide, indium tin oxide (ITO), tin oxide, or the like. As the transparent electrode, for example, those described in pages 232 to 239 of “Liquid Crystal Device Handbook” (Japan Society for the Promotion of Science 142nd edition, Nikkan Kogyo Shimbun, 1989) can be used.

  The display device of the present invention can be produced, for example, by placing a pair of substrates facing each other at intervals of 1 to 50 μm via a spacer or the like and arranging the liquid crystal composition of the present invention in a space formed between the substrates. it can. As the spacer, for example, those described in pages 257 to 262 of “Liquid Crystal Device Handbook” (edited by Japan Society for the Promotion of Science 142nd Committee, Nikkan Kogyo Shimbun, 1989) can be used. The liquid crystal composition of the present invention can be disposed in a space between substrates by coating or printing on the substrates.

  The display device of the present invention can be driven by a simple matrix driving method or an active matrix driving method using a thin film transistor (TFT). The driving method is described in detail, for example, on pages 387 to 460 of “Liquid Crystal Device Handbook” (edited by the 142th Committee of the Japan Society for the Promotion of Science, Nikkan Kogyo Shimbun, 1989). Available as a method.

  In addition to the compound represented by the general formula 1 of the present invention, the display device of the present invention can employ compounds and members generally used for display devices as appropriate.

4). Optical Element The compounds and compositions of the present invention can also be suitably used as an optical element described below.
Specifically, the optical element in the present invention includes a circularly polarized light-emitting film, an optical film, a retardation film, a ferroelectric film, an antiferroelectric film, a functional film such as a piezoelectric film, etc., and (circular) polarized light. Functions of light-emitting elements, laser oscillation elements by optical excitation or electric field excitation (based on the primary photonic crystal effect), LCD backlights, non-linear optical elements, electro-optical elements, pyroelectric elements, piezoelectric elements, light modulation elements, etc. This refers to a sexual element.

In the present invention, the optical element is, for example, 1) a method in which the compound (or composition) of the present invention is applied to a single support or a pair of supports (cells, etc.) and then crosslinked, or 2) It can be produced by a method of injecting the compound (or composition) of the invention as it is.
Since these optical elements use the compound represented by the general formula 1 having a large absolute value of dielectric anisotropy Δε and a negative value, the wide-angle visual field can be widened.

  In the case of a phase difference plate, a transparent support is used as the support. Although there is no restriction | limiting in particular as this transparent support body, Glass, TAC, PET, PEN, COP, PMMA, PS, a polycarbonate, etc. can be used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.

[Example 1]

<Synthesis of Exemplary Compound (1)>
(Synthesis of Compound 1a)
A 500 ml three-necked flask purged with nitrogen was charged with 1.0 mol / l lithium aluminum hydride (100 ml (0.1 mol), manufactured by Aldrich), and the internal temperature was adjusted to 5 ° C. or lower with an ice bath. Diethyl normal butylmalonate (8.0 g (0.037 mol)) was dissolved in 100 ml of dehydrated THF and added dropwise with a dropping funnel over 30 minutes. After completion of the dropwise addition, the reaction solvent was refluxed by heating to an internal temperature of 65 ° C. in a hot water bath. After 4 hours, disappearance of the raw materials was confirmed by thin layer chromatography, and the temperature of the reaction solution was lowered to 30 ° C or lower. 10 ml of water was added to the reaction solution to decompose unreacted lithium aluminum hydride. A 1N aqueous hydrochloric acid solution was added until the pH reached 2 or more, and the reaction solution was extracted three times with 50 ml of ethyl acetate. The obtained ethyl acetate solution was washed with saturated brine and aqueous sodium hydrogen carbonate solution, and dried over magnesium sulfate. Magnesium sulfate was filtered off, and the resulting solution was concentrated to obtain 5.0 g of a crude product. The component organism was purified by flash column chromatography (hexane / ethyl acetate = 2/1) to obtain 4.4 g (yield 90%) of Compound 1a.

(Synthesis of Compound 1b)
Dean Stark trap in a 200 ml eggplant flask with terephthalaldehyde acid (2.0 g (15.1 mmol) manufactured by Tokyo Chemical Industry), Compound 1a (2.3 g (15.1 mmol)), AMBERLIST (100 mg, manufactured by ICN Biomedicals), 20 ml of toluene And a Dean Stark reflux tube and a Dimroth were attached. The mixture was heated to reflux in an oil bath for 4 hours, and the reaction solution was cooled with water. The reaction solution was filtered, and the compound in the container was washed out with ethyl acetate. The obtained toluene-ethyl acetate solution was concentrated. Purification by silica gel chromatography (eluent: hexane / ethyl acetate = 3/1) gave 3.4 g (yield 86%) of compound 1b.

(Synthesis of Compound 1c)
In a 1.0 liter eggplant flask, 2,3-dicyanohydroquinone (70 g (0.44 mol), manufactured by Aldrich), 1-bromopentane (70 g (0.46 mol), manufactured by Tokyo Chemical Industry) sodium hydroxide (20 g (. 5 mol))) and 400 ml of water. The reaction vessel was heated in a 120 ° C. oil bath, and the reaction solvent was refluxed for 6 hours. The reaction solution was cooled to 30 ° C., and the solid was collected by filtration to obtain 95.6 g of a crude product. The crude product was purified by column chromatography with an eluent: hexane / ethyl acetate = 3/1 to 1/1 to obtain 82.1 g (yield 80%) of Compound 1c.

(Synthesis of Compound 1)
Compound 1b (500 mg (1.9 mmol)) and thionyl chloride (0.44 ml (6.0 mmol)) were placed in a nitrogen-substituted 100 ml three-necked flask. After stirring at 40 ° C. for 1 hour, thionyl chloride was removed under reduced pressure. To this was added 2.5 ml of dry ethyl acetate. This is referred to as an “acid chloride solution”.
Compound 1c (440 mg (1.9 mmol)), potassium carbonate (1.4 g (10 mmol)), and 5 ml of dehydrated acetonitrile were added to a nitrogen-substituted 100 ml three-necked flask. The acid chloride solution was added dropwise while maintaining the temperature of the solution at 30 ° C. The mixture was stirred at the same temperature for 3 hours. 20 ml of ethyl acetate and 5 ml of water were added to the reaction solution, and the organic layer was separated with a separatory funnel. The obtained organic layer was dried over magnesium sulfate. Magnesium sulfate was filtered off, and the obtained ethyl acetate solution was concentrated to obtain 800 mg of a crude product. The resulting crude product was purified by silica gel chromatography (eluent: hexane / ethyl acetate = 3/1) to obtain 750 mg (yield 83%) of Compound 1. Furthermore, in order to obtain highly pure compound 1, 710 mg (yield 78%) of highly pure compound 1 was obtained by recrystallization with 10 ml of methanol.

¹ H NMR (300 MHz, CDCl ₃ ): δ 0.86-0.96 (m, 6H), 1.11-1.18 (m, 1H), 1.27-1.56 (m, 8H), 1 85-1.92 (m, 2H), 2.11-2.20 (m, 1H), 3.57 (t, 2H), 4.13 (dd, 2H), 4.27 (dd, 2H) ), 5.48 (s, 1H), 7.23 (d, 1H), 7.64-7.68 (m, 3H), 8.21 (d, 2H)

  The dielectric anisotropy Δε was calculated by extrapolation using liquid crystal ZLI-1132 manufactured by Merck.

Δε = −19

  As shown above, a compound having a negatively large Δε value could be synthesized.

[Comparative Example 1]
For comparison, dielectric anisotropy was determined in the same manner as in Example 1 using the following Comparative Compounds-1 and 2.

Comparative compound-1: Δε = + 32
Comparative compound-2: Δε = −13

  By comparison with the comparative compound, it can be seen that the compound of the present invention exhibits negative dielectric anisotropy and has a large value.

[Example 2]
Compound 1 of the present invention was mixed with 10% by mass of a commercially available liquid crystal MLC-6608 (manufactured by Merck) having a negative Δε, and injected into a vertical alignment cell (manufactured by EHC), and the threshold voltage was measured. For comparison, the comparative compound-2 was evaluated in the same manner. As a result, the threshold voltage was 1.2 times higher than that of the liquid crystal composition containing the compound of the present invention, and the response time was 1.4 times longer. It was. This shows that the compound of the present invention has a smaller elastic constant than the comparative compound.

[Example 3]
(Synthesis of Compound 4)
Compound (4) was synthesized according to the following scheme.

(Synthesis of Compound 4a)
To a 20% ethanol solution (36 g) of sodium ethoxide, diethyl malonate (manufactured by Wako Pure Chemical Industries, Ltd.) (17 g) was added, followed by dodecyl bromide (manufactured by Wako Pure Chemical Industries, Ltd.) (26.4 g), and heated under reflux. Stir for 3 hours. The reaction mixture was neutralized with 1N aqueous hydrochloric acid and extracted with ethyl acetate. The extract was dried over magnesium sulfate and concentrated under reduced pressure. The concentrated residue was purified by silica gel column chromatography to obtain compound 4a (23 g).

(Synthesis of Compound 4b)
A 500 ml three-necked flask purged with nitrogen was charged with 1.0 mol / l lithium aluminum hydride (100 ml (0.1 mol), manufactured by Aldrich), and the internal temperature was adjusted to 5 ° C. or lower with an ice bath. Compound 4a (19 g) was dissolved in 20 ml of dehydrated THF and added dropwise with a dropping funnel over 30 minutes. After completion of the dropwise addition, the reaction solvent was refluxed by heating to an internal temperature of 65 ° C. in a hot water bath. After 4 hours, disappearance of the raw materials was confirmed by thin layer chromatography, and the temperature of the reaction solution was lowered to 30 ° C or lower. 10 ml of water was added to the reaction solution to decompose unreacted lithium aluminum hydride. A 1N aqueous hydrochloric acid solution was added until the pH reached 2 or more, and the reaction solution was extracted three times with 50 ml of ethyl acetate. The obtained ethyl acetate solution was washed with saturated brine and aqueous sodium hydrogen carbonate solution, and dried over magnesium sulfate. Magnesium sulfate was filtered off and the resulting solution was concentrated. The concentrated residue was purified by silica gel column chromatography (hexane / ethyl acetate = 2/1) to obtain 12 g of compound 4b.

(Synthesis of Compound 4c)
A Dean-Stark trap was charged with terephthalaldehyde acid (2.0 g, manufactured by Tokyo Chemical Industry), Compound 4b (3.7 g), AMBERLIST (100 mg, manufactured by ICN Biomedicals), and 20 ml of toluene in a 200-ml eggplant flask. And heated to reflux in an oil bath for 4 hours. The reaction solution was cooled with water and filtered. The obtained toluene-ethyl acetate solution was concentrated under reduced pressure. The concentrated residue was purified by silica gel chromatography (eluent: hexane / ethyl acetate = 3/1) to obtain 5.1 g of compound 4c.

(Synthesis of Compound 4d)
To compound 4c (2 g) was added thionyl chloride (0.43 ml), and the mixture was stirred at 40 ° C. for 1 hour, and then thionyl chloride was removed under reduced pressure. To this was added 2.5 ml of dry ethyl acetate. This is referred to as an “acid chloride solution”.
2,3-dicyanohydroquinone (0.85 g, manufactured by Aldrich), potassium carbonate (1.4 g), and 5 ml of dehydrated acetonitrile were added. The acid chloride solution was added dropwise while maintaining the temperature of the solution at 30 ° C. The mixture was stirred at the same temperature for 3 hours. 20 ml of ethyl acetate and 5 ml of water were added to the reaction solution, and the organic layer was separated with a separatory funnel. The obtained organic layer was dried over magnesium sulfate and concentrated under reduced pressure. The concentrated residue was purified by silica gel chromatography to obtain 1.6 g of compound 4d.

(Synthesis of Compound 4)
A solution of compound 4d (1.6 g), triphenylphosphine (manufactured by Wako Pure Chemical Industries, Ltd.) (1.2 g) and 2-hexenyl alcohol (0.31 g) in THF (20 ml) was cooled to 40 ° C. with azodicarboxylic acid ester. % Toluene solution (manufactured by Tokyo Chemical Industry) (0.84 ml) was added dropwise and stirred for 8 hours. The reaction mixture was poured into water / ethyl acetate, and the organic layer was washed with 1N aqueous hydrochloric acid, dried over magnesium sulfate, and concentrated under reduced pressure. The concentrated residue was purified by silica gel column chromatography to obtain liquid crystal compound (4) (1.4 g) (identification of the compound was performed by elemental analysis, NMR and MASS spectrum). Appearance is white solid.

  As in Example 1, the dielectric anisotropy was measured and showed a large negative value.

Claims (4)

A compound represented by the following general formula 1.

Wherein, R ¹ and R ² are each independently (including deuterium atom) hydrogen atom, (including a cycloalkyl group, a bicycloalkyl group, a tricycloalkyl group) A alkyl group, an alkenyl group (cycloalkenyl group, bicycloalkyl including cycloalkenyl group), represents the aryl group, an alkoxy group, an alkenyloxy group, X ¹ to X ¹² are each independently, comprise a hydrogen atom (deuterium atom), a halogen atom, an alkyl group ( cycloalkyl group, a bicycloalkyl group, seen including a tricycloalkyl group, including) a fluorinated alkyl group, a sheet anode group, Y ¹ and Y ^2, each independently, a chloro group, fluoro group, or a cyano And at least one of Y ¹ and Y ² is a cyano group. ] A liquid crystal composition containing at least one compound according to claim 1 . A retardation plate having at least one optically anisotropic layer on a transparent support,
A retardation plate containing at least one of the compounds according to claim 1 in the optically anisotropic layer. A display device comprising: a pair of electrode substrates; and a liquid crystal layer disposed between the pair of electrode substrates, wherein the liquid crystal layer contains at least one compound according to claim 1 .