JPH11349548A - New liquid crystal compound comprising 6-cyanonaphthalene derivative and liquid crystal composition containing the same and liquid crystal element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject new compound useful for liquid crystal compositions and having a structure in which one or all of the 4-7 positions of a naphthalene ring are substituted by fluorine atoms as polar groups. SOLUTION: A compound of formula I (R is a 1-12C alkyl or the like; the ring A and the ring B are each trans-1,4-cyclohexylene or the like; L and M form CH2 CH2 or the like or are each a single bond; X<1> to X<3> are each H or fluorine atom wherein at least one of X<1> to X<3> is fluorine atom). For example, a compound of formula II. The compound of formula I is obtained by reacting a compound of formula III (W<a> is a halogen; Z<a> is H, methoxy or the like) with magnesium, reacting the obtained Grignard reagent with a 4- alkylcyclohexanone, subjecting the obtained cyclohexanol derivative to a dehydration reaction in the presence of an acid catalyst, catalytically reducing the obtained cyclohexenylnaphthalene derivative, if necessary, isomerizing the cyclohexane ring of the product, and subsequently converting the Z<a> of the obtained compound of formula IV (R<a> is a 1-7C alkyl) into a cyano group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel liquid crystal compound having a fluorine-substituted 6-cyanonaphthyl group, a liquid crystal composition containing the compound, and a liquid crystal display device using the same, which is useful as an electro-optical liquid crystal display material. About.

[0002]

2. Description of the Related Art Liquid crystal display elements have been used in various measuring instruments such as watches and calculators, panels for automobiles, word processors, electronic organizers, printers, computers, televisions and the like. Typical liquid crystal display systems are TN (twisted nematic) type, STN (super twisted nematic) type, DS (dynamic light scattering) type, GH (guest / host) type or FLC capable of high-speed response. (Ferroelectric liquid crystal). As a driving method, a multiplex driving has been generally used instead of the conventional static driving, and a simple matrix method, more recently, an active matrix method has been put to practical use. As the liquid crystal material used for these, a great variety of compounds have been synthesized so far, and they are used according to the display system, the driving system, or the application.

A liquid crystal compound is generally composed of a central skeleton portion called a core and side chain portions on both sides. Usually, at least one of the side chain portions is often a chain group, but in the case of a so-called p-type liquid crystal having a positive dielectric anisotropy, the other side chain portion is a polar group.

The polar groups used in liquid crystal compounds include:
A cyano group is typical. The liquid crystal compound having a cyano group has excellent properties such as high polarity and excellent liquid crystallinity, though slightly higher in viscosity than a liquid crystal compound having another polar group.

[0005] These cyano groups used as polar groups are usually introduced directly to the phenyl group at the molecular end. Therefore, compounds are almost limited to compounds having a 4-cyanophenyl group, a 3-fluoro-4-cyanophenyl group or a 3,5-difluoro-4-cyanophenyl group at one end of the molecule. However, it is the fact that these cyano-based liquid crystal compounds alone cannot sufficiently satisfy the required characteristics of a liquid crystal composition that is becoming more sophisticated year by year.

Other liquid crystal compounds having a chemical structure in which a cyano group is directly linked to another kind of ring structure as a polar group are known. For example, a liquid crystal compound having a 6-cyanonaphthyl group has already been reported (D. Coates et al., Mol. Cryst. Liq. Cry.
St., 37 249 (1976)), which shows that a 6-cyanonaphthyl group has intermediate properties between a 4-cyanophenyl group and a 4'-cyanobiphenyl-4-yl group. According to studies by the present inventors, it has been found that the liquid crystal compound having the 6-cyanonaphthyl group has excellent response characteristics.

However, it cannot be said that a 6-cyanonaphthyl group has a sufficiently large polarity, so that a liquid crystal compound having a 6-cyanonaphthyl group cannot obtain a very large dielectric anisotropy (Δε). .

In order to increase the dielectric anisotropy, for example, the aforementioned 3-fluoro-4-cyanophenyl group or 3,5
It is effective to introduce a fluorine atom into the aromatic ring directly connected to the cyano group in the same direction as the cyano group, such as -difluoro-4-cyanophenyl group. Therefore, in the case of a 6-cyanonaphthyl group, it is considered effective to introduce a fluorine atom at the 4-, 5-, 6-, and 7-positions. However, when a fluorine atom is substituted at such a position,
Liquid crystal compounds having a cyanonaphthyl group have not been known at all.

[0009]

The problem to be solved by the present invention is that a fluorine atom is substituted as a polar group at a part or all of the 4-, 5-, 6- and 7-positions of a naphthalene ring.
-To provide a novel liquid crystal compound having a cyanonaphthalene skeleton structure, and to provide a practical liquid crystal composition using the compound.

[0010]

The present invention has been made in order to solve the above problems. General formula (I)

[0011]

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(Wherein R represents an alkyl group having 1 to 12 carbon atoms, an alkoxyl group or an alkoxylalkyl group having 2 to 12 carbon atoms, an alkenyl group or an alkenyloxy group, and ring A is trans-1,4 -Cyclohexylene group, 1,4-phenylene group, 2-fluoro-1,4
Represents a -phenylene group or a 2,6-difluoro-1,4-phenylene group, and ring B represents a trans-1,4-cyclohexylene group, a 1,4-phenylene group, a 2-fluoro-1,
4-phenylene group, 2,6-difluoro-1,4-phenylene group or a single bond, L and M are each independently _{-CH 2 CH 2 -, - CH} 2 O -, - OCH 2 -, - CO
O -, - OCO -, - CF 2 O -, - OCF 2 -, - CH
₂ CH ₂ CH ₂ CH ₂ —, —CF ＝ CF—, —C≡C— or a single bond. When ring B represents a single bond, M represents a single bond. X ^{1 to} X ³ each independently represent a hydrogen atom or a fluorine atom, and at least one of them represents a fluorine atom. A novel liquid crystalline compound which is a fluorine-substituted 6-cyanonaphthalene derivative represented by the following formula: 2. ^2. The compound according to the above 1, wherein in formula (I), X ² represents a fluorine atom. 3. In the general formula (I), L and M represent —CH ₂ CH
_3. The compound according to the above 1 or 2, wherein the compound represents 2-, -COO-, -C≡C- or a single bond. 4. 4. The compound according to the above 1, 2, or 3, wherein in formula (I), at least one of L and M represents a single bond. 5. The compound according to the above 1, 2, 3 or 4, wherein in the general formula (I), R represents a linear alkyl group having 1 to 7 carbon atoms. 6. 2. A liquid crystal composition comprising the compound represented by the general formula (I) as described in 1 above. 7. 7. The liquid crystal composition according to the above item 6, which is used for STN display. 8. 7. A liquid crystal device comprising the liquid crystal composition according to the above item 6 as a constituent element. 9. An STN liquid crystal display device using the liquid crystal composition according to the above item 7. Was found as a means for solving the above-mentioned problem.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the present invention will be described below. The present invention provides a compound represented by the general formula (I):

[0014]

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A novel liquid crystal compound which is a 6-cyanonaphthalene derivative represented by the formula: In the formula, R represents an alkyl group having 1 to 12 carbon atoms, an alkoxyl group or an alkoxylalkyl group having 2 to 12 carbon atoms, an alkenyl group or an alkenyloxy group, preferably an alkyl group or an alkenyl group, 1-7 straight-chain alkyl groups are particularly preferred. Ring A is a trans-1,4-cyclohexylene group, 1,4-phenylene group, 2-fluoro-1,4-phenylene group or 2,6-difluoro-1,
Represents a 4-phenylene group, and ring B is trans-1,4-cyclohexylene group, 1,4-phenylene group, 2-fluoro-1,4-phenylene group, 2,6-difluoro-1,
It represents a 4-phenylene group or a single bond, but when low viscosity is required, ring B is preferably a single bond, and when high refractive index anisotropy (Δn) is required, 1,4-phenylene group is preferable. When a large dielectric anisotropy (Δε) is required, at least one of them is preferably a 2-fluoro-1,4-phenylene group or a 2,6-difluoro-1,4-phenylene group. Each L and M are independently -CH ₂ C
H ₂ —, —CH ₂ O—, —OCH ₂ —, —COO—, —O
_{CO -, - CF 2 O -} , - OCF 2 -, - CH 2 CH 2 CH
₂ CH ₂ —, —CF ＝ CF—, —C≡C— or a single bond, preferably —CH ₂ CH ₂ —, —COO—, —C≡C— or a single bond, and in particular at least one is a single bond It is preferably a bond, and when ring B represents a single bond, M represents a single bond. X ^{1 to} X ³ each independently represent a hydrogen atom or a fluorine atom, at least one of which represents a fluorine atom, and when high liquid crystallinity is required, X ¹ and X ³ may be hydrogen atoms. Preferably, when a particularly large Δε is required, it is preferred that at least two or more, particularly two or more including X ² , of X ^{1 to} X ³ are fluorine atoms. The 1,4-position of the cyclohexylene group has a trans configuration.

As described above, the compound of the general formula (I) can include a very wide variety of compounds depending on the selection of R, ring A, ring B, L, M and X ^{1 to} X ³ . Among these, the compounds represented by the following formulas (Iaa) to (Inf) are preferred.

[0017]

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[0018]

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[0019]

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[0020]

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[0021]

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[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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[0030]

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[0031] In the above equations, R ^a represents a linear alkyl group having 1 to 7 carbon atoms, R ^b represents a linear alkenyl group having 2 to 7 carbon atoms, particularly preferably a vinyl group or a 3 Represents a butenyl group. R ^C represents a linear alkenyl group having 4 to 7 carbon atoms, particularly preferably a 3-butenyl group.

Further, in the above formula, (Iaa), (Iab),
(Iac), (Iad), (Ica), (Icb), (Icc),
(Icd), (Ifa), (Ifb), (Ifc), (Ifd),
(Ife), (Iff), (Ifg), (Ifh), (Ifk),
(Iga), (Igb), (Igc), (Igf), (Iia),
(Iib), (Iic), (Ika), (Ikb), (Ikc),
(Ikd), (Ila), (Ilb), (Ilc), (Ima),
The compounds (Imb), (Imc), (Imd), (Ime) and (Imf) are particularly preferred.

The compound of the general formula (I) according to the present invention has an R,
It can be produced as follows according to ring A, ring B, L and M. (I) In the case of compounds represented by the general formulas (Iaa) to (Iab), the general formula (IIa)

[0034]

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[0035] (wherein, X ¹ to X ³ represents the same meaning as in general formula (I), W ^a chlorine, it represents a halogen atom bromine or iodine, .Z preferably a bromine atom ^a
Represents a protecting group for a carboxyl group such as a methoxy group, a hydrogen atom or a 4,4-dimethyl-1,3-oxazolin-2-en-2-yl group. ) Is reacted with magnesium to obtain a Grignard reagent, or lithiated with an alkyl lithium such as butyl lithium to obtain an organometallic reagent, which is represented by the general formula (I)
IIa)

[0036]

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(Wherein ^Ra represents a linear alkyl group having 1 to 7 carbon atoms), and the resulting cyclohexanol derivative is reacted in the presence of an acid catalyst. To the general formula (IV
a)

[0038]

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[0039] (wherein, X ¹ to X ³ is the general formula (I), Z ^a represents the same meaning as in the general formula (IIa), the R ^a represents a linear alkyl group having 1 to 7 carbon atoms ) Is obtained. This is catalytically reduced, and if necessary, a cyclohexane ring is isomerized to obtain a compound represented by the general formula (Va):

[0040]

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[0041] (wherein, X ¹ to X ³ is the general formula (I), Z ^a represents the same meaning as in the general formula (IIa), the R ^a represents a linear alkyl group having 1 to 7 carbon atoms ) Is obtained. This is Z ^a
Is a hydrogen atom, halogenated (brominated or iodinated) and then cyanated with copper (I) cyanide, or carboxylated (reacted with carbon dioxide after lithiation, or peracid after acetylation) in due to be oxidized) further or dehydration by an acid chloride and then reacted with ammonia to give the amide after, or in the same manner to obtain a direct acid chloride from oxalic acid chloride, also Z ^a
Is a methoxy group, the naphthol derivative obtained by demethylation is converted to a triflate with trifluoromethanesulfonic acid anhydride (or acid chloride), which is reacted with copper (I) cyanide in the presence of a transition metal catalyst either by, or Z ^a is generally described above by converting directly a cyano group likewise be converted to a cyano group, or phosphorus oxychloride, etc. the carboxylic acid obtained by deprotection in the case of a methoxy group Compounds represented by formulas (Iaa) to (Iac) can be produced.

Here, instead of the cyclohexanone of the formula (IIIa), a compound of the general formula (IIIb) or (IIIc)

[0043]

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(Wherein ^Ra represents a straight-chain alkyl group having 1 to 7 carbon atoms), by using a 4-substituted cyclohexanone derivative represented by the following general formulas (Ica) to (Ica):
cc) and the compounds of the general formulas (Ida) to (Idc) can be produced in the same manner. (Ii) In the case of the compounds represented by the general formulas (Iba) to (Ibb), the compound represented by the general formula (VIa) is used instead of the 4-alkylcyclohexanone of (IIIa) in (i).

[0045]

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(Wherein ^Ra represents a linear alkyl group having 1 to 7 carbon atoms), and the same reaction is carried out using a cyclohexaneethanal derivative represented by the formula (I).
ba) to (Ibb) can be produced.

Here, instead of the cyclohexaneethanal of (VIa), general formulas (VIb), (VIc) or (VId)

[0048]

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(Wherein ^Ra represents a linear alkyl group having 1 to 7 carbon atoms), the use of an aldehyde represented by the general formulas (Iea) to (Ieb) and the general formula (Ij)
Each compound of a) to (Ijd) can be produced in the same manner. (Iii) In the case of the compounds represented by the general formulas (Iac) to (Iad), the organometallic reactant prepared from (IIa) is converted to a compound of the formula (III)
d)

[0050]

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After reacting with cyclohexane-1,4-dionemonoethylene acetal, dehydrating in the presence of an acid catalyst, reacetalizing if necessary, and catalytic reduction,
By deacetalization, the compound represented by the general formula (VIIa)

[0052]

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[0053] obtained (wherein, X ¹ to X ³ is the general formula (I), Z ^a have the general formula (. Represents the same meaning as in IIa)) naphthyl cyclohexanone derivative represented by the. The formula (VIIIa)

[0054]

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By reacting a Wittig reagent represented by the following formula (IXa):

[0056]

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[0057] obtained (wherein, X ¹ to X ³ is the general formula (I), Z ^a have the general formula (. Represents the same meaning as in IIa)) cyclohexane carbaldehyde derivative represented by the. The formula (VIIIb)

[0058]

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By reacting a Wittig reagent represented by the following formula, and then converting Z ^a to a cyano group in the same manner, it is possible to produce a compound in which R ^b is a vinyl group in the general formulas (Iac) to (Iad). it can. (IXa) is further reacted with the Wittig reagent of (VIIIa) twice, and then reacted with the Wittig reagent of (VIIIb), whereby R ^b in the general formulas (Iac) to (Iad) is 3-butenyl. Compounds that are groups can be prepared. Here, conversion of Za to ^a cyano group is represented by (VIIa)
May be performed in a pre-step of deacetalization into

Here, the cyclohexane of (IIId)
In place of 1,4-dione monoethylene acetal, a compound of the formula (IIIe)

[0061]

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The compounds of the general formulas (Ice) to (Icf) can be produced by the same reaction using the bicyclohexane-4,4'-dione monoethylene acetal. (Iv) In the case of compounds represented by the general formulas (Ifa) to (Ifc) The organometallic reactant (or Grignard or organolithium reactant) prepared from (IIa) is reacted with a trialkyl ester of boric acid. Then, an organic boric acid obtained by hydrolysis with an acid can also be used) with the general formula (Xa)

[0063]

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(Wherein, ^Ra represents a linear alkyl group having 1 to 7 carbon atoms, and Y represents a halogen atom such as bromine or iodine or a leaving group such as a trifluoromethanesulfonyloxy group). are reacted in the presence of a benzene derivative and a transition metal catalyst represented, then be prepared by converting in the same manner as a cyano group and Z ^a. Alternatively, the general formula (X
b)

[0065]

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[0066] (wherein, R ^a represents a linear alkyl group having 1 to 7 carbon atoms, W ^a has the general formula represent the same meaning as in (IIa).) Are prepared analogously from the benzene derivative of The organometallic reactant represented by the general formula (IIb)

[0067]

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[0068] (wherein, X ¹ to X ³ is the general formula (I), Z ^a have the general formula (IIa), Y is as in formula (Xa) represent the same meaning.) Fluoro naphthalene derivative represented by the It can also be produced by reacting in the same manner as described above. Here, the transition metal catalyst is preferably a palladium (0) complex, a palladium (II) complex, a nickel (II) complex or the like.

Here, the benzene derivative of the general formula (Xc), (Xd), (Xe) or (Xf) is substituted for the benzene derivative of (Xa).

[0070]

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Wherein R ^a represents a linear alkyl group having 1 to 7 carbon atoms, R ^c represents a linear alkenyl group having 4 to 7 carbon atoms, and Y represents a general formula (Xa) In the same manner as described above), the compounds of general formulas (Ifd) to (Ifl) can be obtained.

Further, in place of the benzene derivative of (Xa), general formula (Xg), general formula (Xh) or general formula (Xh)
i) phenylcyclohexane derivative

[0073]

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(Wherein ^Ra represents a linear alkyl group having 1 to 7 carbon atoms, and Y represents the same meaning as in the general formula (Xa)). Thus, the compounds of the general formulas (Iga) to (Igg) can be produced.

Further, in place of the benzene derivative of (Xa), a phenethylcyclohexane derivative of the general formula (Xj) or (Xk)

[0076]

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(Wherein ^Ra represents a linear alkyl group having 1 to 7 carbon atoms, and Y represents the same meaning as in the general formula (Xa)). Thus, each compound of the general formulas (Iha) to (Ihd) can be produced.

Further, instead of the benzene derivative of (Xa), the biphenyl derivative of the general formula (Xl), (Xm), (Xn) or (Xo)

[0079]

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(Wherein, R ^a represents a linear alkyl group having 1 to 7 carbon atoms, R ^c represents a linear alkenyl group having 4 to 7 carbon atoms, and Y represents a general formula (Xa) Having the same meanings as in formula (I).)
Each compound of (Iih) can be produced. (V) In the case of compounds represented by the general formulas (Ika) to (Ikb), the general formula (IIc)

[0081]

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(Wherein X ^{1 to} X ³ have the same meanings as in the general formula (I), Y has the same meaning as in the general formula (Xa), and Z ^b has a cyano group, a methoxy group, a hydroxyl group or an alkoxycarbonyl group, 4 , 4-dimethyl-1,3-oxazoline-2-ene-2
-Represents a protecting group for a carboxyl group such as an yl group. ) And a general formula (XIa)

[0083]

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(Wherein ^Ra represents a linear alkyl group having 1 to 7 carbon atoms) with a phenylacetylene derivative represented by the following formula:
Then, when Z ^b is other than a cyano group, the compounds represented by the general formulas (Ika) to (Ikb) can be obtained by converting them to a cyano group.

Here, the phenylacetylene derivative of the general formula (XIb), (XIc), (XId) or (XIe) is replaced with the phenylacetylene derivative of the formula (XIa).

[0086]

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(Wherein ^Ra represents a linear alkyl group having 1 to 7 carbon atoms and R ^c represents a linear alkenyl group having 4 to 7 carbon atoms). Thus, each compound represented by the general formulas (Ikc) to (Ikh) can be obtained.

Further, in place of the phenylacetylene derivative of (XIa), general formula (XIf) or general formula (XI
g) Cyclohexylphenylacetylene derivative

[0089]

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(Wherein ^Ra represents a straight-chain alkyl group having 1 to 7 carbon atoms), the compounds represented by the general formulas (Ila) to (Ilb) are obtained in the same manner. be able to. (Vi) In the case of compounds represented by the general formulas (Ima) to (Imb), the general formula (IId)

[0091]

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(Wherein X ^{1 to} X ³ have the same meanings as in formula (I)) in the presence of a condensing agent and a naphthol derivative represented by formula (XIIa)

[0093]

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(Wherein R ^a has the same meaning as in general formula (I)), and is reacted with a benzoic acid derivative represented by general formula (Ima) to (Imb). Can be obtained. Alternatively, the acid chloride derivative may be reacted in place of (XIIa).

Here, instead of the benzoic acid derivative of the formula (XIIa), the benzoic acid derivative of the formula (XIIb), the formula (XIIc), the formula (XIId) or the formula (XIIe)

[0096]

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(Wherein, R ^a represents a linear alkyl group having 1 to 7 carbon atoms, and R ^c represents a linear alkenyl group having 4 to 7 carbon atoms) or its acid chloride. In this manner, the compounds represented by the general formulas (Imc) to (Imj) can be obtained in the same manner.

Further, instead of the benzoic acid derivative of the formula (XIIa), the cyclohexylbenzoic acid derivative of the formula (XIIf), (XIIg) or (XIIh)

[0099]

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(Wherein, ^Ra represents a linear alkyl group having 1 to 7 carbon atoms) or an acid chloride thereof, which is similarly represented by the general formulas (Ina) to (Inf). Each compound can be obtained.

Compounds represented by the general formula (I) other than those described above can be produced in the same manner or by applying the same. Representative examples of the compound represented by the general formula (I) thus produced are shown in Table 1.

[0102]

[Table 1]

(In the table, Cr represents a crystal phase, N represents a nematic phase, S represents a smectic phase, and I represents an isotropic liquid phase. The 1,4-cyclohexylene group has a trans configuration. (The phase transition temperature is represented by “° C.”.) As can be seen from Table 1, many compounds represented by the general formula (I) exhibit relatively excellent liquid crystallinity. In addition, since a fluorine atom is introduced into the naphthalene ring in the same direction as the cyano group, it has a large polarity and exhibits strong characteristics as a p-type liquid crystal.
Further, it is excellent in compatibility with other liquid crystal compounds or liquid crystal compositions including general-purpose liquid crystals, so that it can be suitably used as a material for liquid crystal display cells in a state of a mixture thereof. The compound (I) can be used in any of the various display methods described above, but is suitable for use in a TN-type display element and an STN display element, and is particularly used as a polar component of a liquid crystal material for STN display. Is preferred.

Preferred representative examples of the nematic liquid crystal compound which can be used as a mixture with the compound represented by the general formula (I) include, for example, a phenyl benzoate derivative, a phenyl cyclohexanecarboxylate derivative,
Biphenyl-4-yl cyclohexanecarboxylate derivative, phenyl cyclohexanecarbonyloxybenzoate derivative, phenyl cyclohexylbenzoate derivative, cyclohexyl cyclohexylbenzoate derivative, biphenyl derivative, cyclohexylbenzene derivative, terphenyl derivative, bicyclohexane derivative, 4-cyclohexylbiphenyl derivative A 4-phenylbicyclohexane derivative, a tercyclohexane derivative, a 1,2-dicyclohexylethane derivative, a 1,2-diphenylethane derivative,
1,2-diphenylethyne derivative, (2-cyclohexylethyl) benzene derivative, 4-phenethylbicyclohexane derivative, 4- (2-cyclohexylethyl) biphenyl derivative, 1- (4-phenyl) cyclohexyl-
2-cyclohexylethane derivative, 1- (4-cyclohexylphenyl) -2-phenylethyne derivative, phenylpyrimidine derivative, (4-biphenyl-4-yl) pyrimidine derivative, phenylpyridine derivative, (4-biphenyl-4-yl) And pyridine derivatives.

The effects of using the compound of the general formula (I) of the present invention as a component of a liquid crystal composition are shown below. Formula (I-1) shown in Table 1

[0106]

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20% by weight of the compound of formula (I) and a general-purpose n-type host liquid crystal (H)

[0108]

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When a nematic liquid crystal composition (M-1) consisting of 80% by weight was prepared, the liquid crystal phase maximum temperature (T _NI ) was 78.9 ° C. This (M-1) is 1
After being left at 50 ° C. for 20 hours, its T _NI was measured, and it showed almost no change at 78.5 ° C. as compared to before heating. In addition, the ultraviolet irradiation for 20 hours, but also T _NI
Did not change. On the other hand, this (M-1) is -2
After standing at 0 ° C. for 2 weeks, no precipitation of crystals or phase separation was observed. The crystal was cooled to -60 ° C for crystallization, and its melting point ( _TCN ) was measured to be -2 ° C.

Next, (M-1) was converted to a T cell having a cell thickness of 8.0 μm.
A liquid crystal element was prepared by filling in an N cell, and its electro-optical properties were measured. The results were as follows. Nematic phase maximum temperature (T _NI ) 78.9 ° C. Dielectric anisotropy (Δε) 3.2 Threshold voltage (Vth) 2.14 V Response time (τ) 40.0 ms Refractive index anisotropy (Δn) 0. On the other hand, physical properties and electro-optical properties of the host liquid crystal (H) alone are as follows.

Nematic phase upper limit temperature (T _NI ) 72.5 ° C. Dielectric anisotropy (Δε) −1.3 Refractive index anisotropy (Δn) 0.085 Here, the response time is defined as a rise time (τr). This is the response time at the time of voltage application at which the fall time (τd) becomes equal. The host liquid crystal (H) does not respond because it is n-type,
In (M-1), the dielectric anisotropy (Δε) was increased to 3.2 by adding 20% of (I-1), and a high-speed response of 40 ms was possible. In addition, the maximum temperature of the nematic phase (T _NI ) is 78.9 ° C., an increase of 6 ° or more. Further, it can be seen that the refractive index anisotropy (Δn) has also increased.

On the other hand, 6
-A cyanonaphthalene derivative (A)

[0113]

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A nematic liquid crystal composition (MA) comprising 20% by weight and 80% by weight of the host liquid crystal (H) was prepared. A liquid crystal element was prepared in the same manner, and its electro-optical characteristics were measured. The results were as follows.

Nematic phase maximum temperature (T _NI ) 81.2 ° C. Dielectric anisotropy (Δε) 2.2 Threshold voltage (Vth) 2.68 V Response time (τ) 37.5 ms Refractive index anisotropy (Δn) 0.108 (M−A) has a slightly higher T _NI than (M−1) and a slightly reduced response time, but has a significant decrease in Δε, which results in a significant increase in the threshold voltage (Vth). You can see that it is. When (MA) was similarly left at -20 ° C, crystals precipitated within one week.

Next, the 3-fluoro-4-cyanobenzene derivative (B)

[0117]

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A nematic liquid crystal composition (MB) consisting of 20% by weight and 80% by weight of the host liquid crystal (H) was prepared. A liquid crystal element was prepared in the same manner, and its electro-optical characteristics were measured. The results were as follows.

Nematic phase upper limit temperature (T _NI ) 58.5 ° C. Dielectric anisotropy (Δε) 3.6 Threshold voltage (Vth) 2.2 V Response time (τ) 36.0 ms Refractive index anisotropy (Δn) It can be seen that Δε of 0.084 (M−B) is larger than that of (M−1) and Vth is more effectively reduced. However, its T _NI was extremely lower than that of (M-1).

As described above, the compound of the formula (I-1)
It has excellent compatibility with other liquid crystal compounds, has a high maximum temperature of the nematic phase, and its addition can greatly increase the dielectric anisotropy to reduce its threshold voltage. It can be seen that, in addition to the feature that the anisotropy can be increased, the compound is more excellent than the conventionally known compounds (A) and (B) having relatively similar structures.

Accordingly, the compound of the general formula (I) can be used in a) a liquid crystal composition having a wide nematic phase temperature range, a low threshold voltage, capable of driving at a low voltage, and c) a high-speed response. Very useful in preparation.

[0122]

EXAMPLES Examples of the present invention are shown below to further explain the present invention. However, the present invention is not limited to these examples.

The phase transition temperature was measured by a polarizing microscope equipped with a temperature control stage and a differential scanning calorimeter (DSC).
Was performed in combination. The structure of the compound was confirmed by a nuclear magnetic resonance spectrum, an infrared resonance spectrum (IR), a mass spectrum (MS) and the like. Example 1 5-Fluoro-6-cyano-2- (trans-4-propyl) cyclohexylnaphthalene (first example)
Synthesis of 1-fluoro-6- (trans-4-propyl) cyclohexylnaphthalen-2-ol 13.4 g (This compound is 6-bromo-2-methoxynaphthalene and magnesium Is reacted with 4-propylcyclohexanone, and the naphthylcyclohexene derivative obtained by dehydration in the presence of an acid is catalytically reduced.
By isomerizing the cyclohexane ring to trans with a strong base in F (potassium t-butoxy), then demethylating with hydrobromic acid, and further fluorinating with N-fluoro-5-trifluoromethoxypyridinium-2-sulfonate Obtained. ) Was dissolved in 55 ml of dichloromethane, and 8.6 ml of trifluoromethanesulfonic anhydride was added dropwise under ice cooling. To this, 4.6 ml of pyridine was added dropwise with care so that the liquid temperature did not exceed 5 ° C., and the mixture was stirred at the same temperature for 1 hour even after completion of the addition. The reaction was stopped by adding 20 ml of water, and the organic layer was further washed twice with 20 ml of water, dried over anhydrous sodium sulfate and dried. Then, the solvent was distilled off under reduced pressure to obtain triflate (1-fluoro-6-trifluoromethanesulfonic acid). 15.1 g of-(trans-4-propyl) cyclohexylnaphthalen-2-yl) were obtained.

8.1 g of this triflate was dissolved in 40 ml of acetonitrile, and 0.5 g of dibromobis (triphenylphosphine) nickel (II), 0.4 g of triphenylphosphine, 0.1 g of zinc powder and 2.5 g of potassium cyanide were added. The mixture was heated and stirred at 16 ° C. for 16 hours. 20 ml of water was added to stop the reaction, and the organic layer was further washed with 20 m of water.
After washing twice with 1 l, the resultant was dehydrated and dried with anhydrous sodium sulfate. Silica gel column chromatography (hexane /
The mixture was purified using ethyl acetate (9/1) and further recrystallized from ethanol to give 5-fluoro-6-cyano-2-.
3.3 g of (trans-4-propyl) cyclohexylnaphthalene were obtained.

The phase transition temperatures are as shown in Table 1. (Example 2) 5,7-difluoro-6-cyano-2-
Synthesis of (trans-4-propyl) cyclohexylnaphthalene (compound of the formula (I-2) in Table 1) In Example 1, 1-fluoro-6- (trans-4
1,3-difluoro-6- (trans-4-propyl) cyclohexylnaphthalen-2-ol (the compound is 1,3-difluoro-6-bromo-2-ol) in place of -propyl) cyclohexylnaphthalen-2-ol. A Grignard reagent prepared from methoxynaphthalene is reacted with 4-propylcyclohexanone, and a naphthylcyclohexene derivative obtained by dehydration in the presence of an acid is catalytically reduced. And then demethylated with hydrobromic acid) to give trifluoromethanesulfonic acid ester, and then cyanation in the same manner to give 5,7-difluoro-6-cyano-2. -(Trans-4-propyl) cyclohexylnaphthalene was obtained.

The following compounds were obtained in the same manner as in Example 1 or 2. 5-fluoro-6-cyano-2- (trans-4-butyl) cyclohexylnaphthalene 5-fluoro-6-cyano-2- (trans-4-pentyl) cyclohexylnaphthalene 5,7-difluoro-6-cyano-2- (Transformer-4
-Butyl) cyclohexylnaphthalene 5,7-difluoro-6-cyano-2- (trans-4
-Pentyl) cyclohexylnaphthalene trans-4'-ethyl-trans-4- (5-fluoro-6-cyanonaphthalen-2-yl) bicyclohexane trans-4'-propyl-trans-4- (5-fluoro-6- Cyanonaphthalen-2-yl) bicyclohexane (compound of the formula (I-6) in Table 1) trans-4'-pentyl-trans-4- (5-fluoro-6-cyanonaphthalen-2-yl) bi Cyclohexane trans-4'-ethyl-trans-4- (5,7-difluoro-6-cyanonaphthalen-2-yl) bicyclohexane trans-4'-propyl-trans-4- (5,7-
Difluoro-6-cyanonaphthalen-2-yl) bicyclohexane trans-4'-pentyl-trans-4- (5,7-
Difluoro-6-cyanonaphthalen-2-yl) bicyclohexane trans-4'-ethyl-trans-4- (4,5,7
-Trifluoro-6-cyanonaphthalen-2-yl) bicyclohexane trans-4'-propyl-trans-4- (4,5
7-trifluoro-6-cyanonaphthalen-2-yl)
Bicyclohexane trans-4′-pentyl-trans-4- (4,5
7-trifluoro-6-cyanonaphthalen-2-yl)
Bicyclohexane 5-fluoro-6-cyano-2- [4- [2- (trans-4-propyl) cyclohexyl] ethyl] cyclohexylnaphthalene 5-fluoro-6-cyano-2- [4- [2- (trans- 4-pentyl) cyclohexyl] ethyl] cyclohexylnaphthalene 5,7-difluoro-6-cyano-2- [4- [2-
(Trans-4-propyl) cyclohexyl] ethyl]
Cyclohexylnaphthalene 5,7-difluoro-6-cyano-2- [4- [2-
(Trans-4-pentyl) cyclohexyl] ethyl]
Cyclohexylnaphthalene (Example 3) 5-fluoro-6-cyano-2- [2-
Synthesis of (trans-4-propylcyclohexyl) ethyl] naphthalene In Example 2, 1,3-difluoro-6-bromo-
1-fluoro-6- instead of 2-methoxynaphthalene
Using bromo-2-methoxynaphthalene, 4-propylcyclohexaneethanal instead of 4-propylcyclohexanone, and 5-fluoro-6-cyano- 2- [2- (Trans-4-propylcyclohexyl) ethyl] naphthalene was obtained.

In the same manner, the following compounds were obtained. 5-fluoro-6-cyano-2- [2- (trans-4
-Pentylcyclohexyl) ethyl] naphthalene 5,7-difluoro-6-cyano-2- [2- (trans-4-propylcyclohexyl) ethyl] naphthalene 5,7-difluoro-6-cyano-2- [2- (trans -4-pentylcyclohexyl) ethyl] naphthalene trans-4'-propyl-trans-4- [2- (5
-Fluoro-6-cyanonaphthalen-2-yl) ethyl] bicyclohexane trans-4'-pentyl-trans-4- [2- (5
-Fluoro-6-cyanonaphthalen-2-yl) ethyl] bicyclohexane trans-4'-propyl-trans-4- [2-
(5,7-Difluoro-6-cyanonaphthalen-2-yl) ethyl] bicyclohexane trans-4′-pentyl-trans-4- [2-
(5,7-Difluoro-6-cyanonaphthalen-2-yl) ethyl] bicyclohexane 5-fluoro-6-cyano-2- [2- [4- (trans-4-propylcyclohexyl) phenyl] ethyl]
Naphthalene 5-fluoro-6-cyano-2- [2- [4- (trans-4-pentylcyclohexyl) phenyl] ethyl]
Naphthalene 5-fluoro-6-cyano-2- [2- [3,5-difluoro-4- (trans-4-propylcyclohexyl) phenyl] ethyl] naphthalene 5-fluoro-6-cyano-2- [2- [ 3,5-difluoro-4- (trans-4-pentylcyclohexyl) phenyl] ethyl] naphthalene (Example 4) 5-fluoro-6-cyano-2- (trans-4'-vinylbicyclohexane-4-yl) Synthesis of Naphthalene A Wittig reagent was prepared from methoxymethyltriphenylphosphonium chloride and potassium t-butoxy in THF under ice cooling. This was followed by trans-4 ′-(5-fluoro-6-methoxynaphthalen-2-yl) bicyclohexane-4-one (this compound was prepared using a Grignard reagent prepared from 1-fluoro-6-bromo-2-methoxynaphthalene. Bicyclohexane-4,4'-dione is reacted with monoethylene acetal, similarly dehydrated, catalytically reduced, and then deacetalized with formic acid).
Was dropped. After reacting for 1 hour, the temperature was returned to room temperature, water was added, and the organic layer was concentrated. Hexane was added for dissolution, and the insoluble triphenylphosphine oxide was separated by filtration and washed with a mixed solvent of methanol / water = 1/1. The crude product obtained by concentrating the hexane layer was dissolved in ethanol, an ethanol solution of potassium hydroxide was added, and the mixture was stirred at room temperature for 1 hour. Water was added, neutralized with dilute hydrochloric acid, and extracted with toluene. The organic layer was washed with water, dehydrated and dried over anhydrous sodium sulfate, the solvent was distilled off, and trans-4 '-(5-fluoro-6-methoxynaphthalen-2-yl) bicyclohexane-trans-4-carbaldehyde was removed. Was obtained. Methoxymethyltriphenylphosphonium iodide and
The Wittig reagent prepared from potassium t-butoxy was reacted similarly to give 5-fluoro-6-methoxy-2- (trans-4'-vinylbicyclohexane-
4-Iy) naphthalene was obtained. This was demethylated in the same manner as in Example 1 to give a trifluoromethanesulfonic acid ester, and then cyanation to give the indicated 5-fluoro-6-cyano-2- (trans-4'-vinylbicyclohexane-4- Il) Naphthalene was obtained.

In the same manner, the following compounds were obtained. 5-fluoro-6-cyano-2- [trans-4'-
(3-Buten-1-yl) bicyclohexane-4-yl] naphthalene 5,7-difluoro-6-cyano-2- (trans-
4'-vinylbicyclohexane-4-yl) naphthalene 5,7-difluoro-6-cyano-2- [trans-
4 '-(3-buten-1-yl) bicyclohexane-4
-Yl] naphthalene 4,5,7-trifluoro-6-cyano-2- (trans-4'-vinylbicyclohexane-4-yl) naphthalene 4,5,7-trifluoro-6-cyano-2- [ Trans-4 '-(3-Buten-1-yl) bicyclohexane-4-yl] naphthalene 5-fluoro-6-cyano-2- (trans-4-vinylcyclohexyl) naphthalene 5-fluoro-6-cyano-2 − [Trans-4- (3
-Buten-1-yl) cyclohexyl] naphthalene 5,7-difluoro-6-cyano-2- (trans-4
-Vinylcyclohexyl) naphthalene 5,7-difluoro-6-cyano-2- [trans-4
-(3-buten-1-yl) cyclohexyl] naphthalene (Example 5) 5-fluoro-6-cyano-2- (4-
Propylphenyl) naphthalene (formula (I-
Synthesis of compound 3) 34 g of 4-propylphenylboric acid (this compound is 1-
Grignard reagent prepared from bromo-4-propylbenzene was reacted with trimethyl borate and then hydrolyzed with hydrochloric acid) and 25.5 g of 6-bromo-2-naphthol in 92 ml of toluene, 46 ml of ethanol And 92 ml of water and dissolved in potassium carbonate 2
5.5 g and 1.3 mg of tetrakistriphenylphosphine palladium (0) were added, and the mixture was stirred at 75 ° C. for 7 hours. Water and toluene were added, and dilute hydrochloric acid was further added until the aqueous layer became weakly acidic. The mixture was extracted with toluene, and the organic layers were combined, washed with water and then with a saturated saline solution, and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure to obtain 41.4 g of 6- (4-propylphenyl) naphthalen-2-ol. This 6- (4-propylphenyl) naphthalene-2
Is dissolved in 50 ml of dichloromethane, and 13.1 g of N-fluoro-5-trifluoromethoxypyridinium-2-sulfonate is added.
Allowed to stir for hours. The oily substance obtained by post-treatment as described above was purified by silica gel column chromatography (hexane / ethyl acetate = 9/1) to give 1-fluoro-6- (4-propylphenyl) naphthalene-2-
10 g of all were obtained. Hereinafter, trifluoromethanesulfonic acid ester was obtained in the same manner as in Example 1 and cyanation was carried out to obtain 1.3 g of the indicated 5-fluoro-6-cyano-2- (4-propylphenyl) naphthalene. Table 1 shows the phase transition temperatures. (Example 6) 5,7-difluoro-6-cyano-2-
Synthesis of (4-propylphenyl) naphthalene 7.3 g of 4-propylphenylboric acid and 10 g of 5,7-difluoro-6-cyanonaphthalen-2-yl trifluoromethanesulfonate (this compound is 5,7-difluoro-6- (Cyanonaphthalen-2-ol was obtained by triflating with trifluoromethanesulfonic anhydride) in 50 ml of DMF, and 0.4 g of tetrakistriphenylphosphinepalladium (0) was added thereto.
Stirred at 8 ° C. for 8 hours. Water and toluene were added, the aqueous layer was extracted with toluene, and the organic layers were combined, washed with water and then with saturated saline, and dried over anhydrous sodium sulfate. The oil obtained by evaporating the solvent under reduced pressure was purified by silica gel column chromatography (hexane / ethyl acetate = 9/1), and further recrystallized from ethanol to give 5,7-difluoro-6-cyano. -2- (4-propylphenyl)
5.8 g of naphthalene crystals were obtained. (Example 7) 5-fluoro-6-cyano-2- (2-
Synthesis of fluoro-4-propylphenyl) naphthalene (compound of formula (I-4) in Table 1) 6-bromo-1-fluoro-2- (4,4, -dimethyl-1,3-oxazoline-2 -En-1-yl) naphthalene 14.7 g (this compound is 6-bromo-1-fluoronaphthalene-2-carboxylic acid chloride and 2-amino-
(Obtained by dehydrating the amide obtained from 2-methylpropanol with thionyl chloride) prepared from 10 g of 2-fluoro-4-propyl-1-iodobenzene and 10 g of tetrakistriphenylphosphine palladium (0) 0. It was added dropwise at 50 ° C. to a solution of 0.1 g of THF in 50 ml. After further stirring for 3 hours, water and toluene were added, the aqueous layer was extracted with toluene, and the organic layers were combined, washed with water and then with saturated saline, and dried over anhydrous sodium sulfate. The crude product obtained by evaporating the solvent under reduced pressure was dissolved in 50 ml of pyridine, and 6.7 g of phosphorus oxychloride was added dropwise at 10 ° C. After further stirring at 5 ° C. for 3 hours, most of the excess phosphorus oxychloride and pyridine were distilled off under reduced pressure, toluene was added, and the mixture was washed with diluted hydrochloric acid, water, and then with saturated saline. The oil obtained by evaporating the solvent under reduced pressure was purified by silica gel column chromatography (hexane / ethyl acetate = 9/1), and further recrystallized from ethanol to give 5-fluoro-6-cyano- 2
5.9 g of-(2-fluoro-4-propylphenyl) naphthalene was obtained.

The following compounds were obtained in the same manner as in Example 5, 6 or 7. 5-fluoro-6-cyano-2- (4-pentylphenyl) naphthalene 5-fluoro-6-cyano-2- (4-heptylphenyl) naphthalene 5-fluoro-6-cyano-2- [4- (3- Butene
1-yl) phenyl] naphthalene 5,7-difluoro-6-cyano-2- (4-pentylphenyl) naphthalene 5,7-difluoro-6-cyano-2- (4-heptylphenyl) naphthalene 5,7-difluoro -6-cyano-2- [4- (3-buten-1-yl) phenyl] naphthalene 4,5,7-trifluoro-6-cyano-2- (4-pentylphenyl) naphthalene 4,5,7- Trifluoro-6-cyano-2- (4-heptylphenyl) naphthalene 4,5,7-trifluoro-6-cyano-2- [4-
(3-Buten-1-yl) phenyl] naphthalene 5-fluoro-6-cyano-2- (2-fluoro-4-
Pentylphenyl) naphthalene 5-fluoro-6-cyano-2- (2-fluoro-4-
Heptylphenyl) naphthalene 5-fluoro-6-cyano-2- [2-fluoro-4-
(3-Buten-1-yl) phenyl] naphthalene 5-fluoro-6-cyano-2- (2,6-difluoro-4-propylphenyl) naphthalene (compound of formula (I-5) in Table 1) 5-fluoro-6-cyano-2- (2,6-difluoro-4-pentylphenyl) naphthalene 5-fluoro-6-cyano-2- (2,6-difluoro-4-heptylphenyl) naphthalene 5-fluoro- 6-cyano-2- [2,6-difluoro-4- (3-buten-1-yl) phenyl] naphthalene 5,7-difluoro-6-cyano-2- (2-fluoro-4-propylphenyl) naphthalene 5,7-difluoro-6-cyano-2- (2-fluoro-4-pentylphenyl) naphthalene 5,7-difluoro-6-cyano-2- (2-fluoro-4-heptyl Phenyl) naphthalene 5,7-difluoro-6-cyano-2- [2-fluoro-4- (3-buten-1-yl) phenyl] naphthalene 5,7-difluoro-6-cyano-2- (2,6 -Difluoro-4-propylphenyl) naphthalene 5,7-difluoro-6-cyano-2- (2,6-difluoro-4-pentylphenyl) naphthalene 5,7-difluoro-6-cyano-2- (2,6 -Difluoro-4-heptylphenyl) naphthalene 5,7-difluoro-6-cyano-2- [2,6-difluoro-4- (3-buten-1-yl) phenyl] naphthalene 5-fluoro-6-cyano- 2- [4- (trans-4
-Ethylcyclohexyl) phenyl] naphthalene 5-fluoro-6-cyano-2- [4- (trans-4
-Propylcyclohexyl) phenyl] naphthalene 5-fluoro-6-cyano-2- [4- (trans-4
-Butylcyclohexyl) phenyl] naphthalene 5-fluoro-6-cyano-2- [4- (trans-4
-Pentylcyclohexyl) phenyl] naphthalene 5,7-difluoro-6-cyano-2- [4- (trans-4-ethylcyclohexyl) phenyl] naphthalene 5,7-difluoro-6-cyano-2- [4- (trans -4-propylcyclohexyl) phenyl] naphthalene 5,7-difluoro-6-cyano-2- [4- (trans-4-butylcyclohexyl) phenyl] naphthalene 5,7-difluoro-6-cyano-2- [4- (Trans-4-pentylcyclohexyl) phenyl] naphthalene 4,5,7-trifluoro-6-cyano-2- [4-
(Trans-4-ethylcyclohexyl) phenyl] naphthalene 4,5,7-trifluoro-6-cyano-2- [4-
(Trans-4-propylcyclohexyl) phenyl]
Naphthalene 4,5,7-trifluoro-6-cyano-2- [4-
(Trans-4-butylcyclohexyl) phenyl] naphthalene 4,5,7-trifluoro-6-cyano-2- [4-
(Trans-4-pentylcyclohexyl) phenylnaphthalene 5-fluoro-6-cyano-2- [2-fluoro-4-
(Trans-4-ethylcyclohexyl) phenyl] naphthalene 5-fluoro-6-cyano-2- [2-fluoro-4-
(Trans-4-propylcyclohexyl) phenyl]
Naphthalene 5-fluoro-6-cyano-2- [2-fluoro-4-
(Trans-4-butylcyclohexyl) phenyl] naphthalene 5-fluoro-6-cyano-2- [2-fluoro-4-
(Trans-4-pentylcyclohexyl) phenyl]
Naphthalene 5,7-difluoro-6-cyano-2- [2-fluoro-4- (trans-4-ethylcyclohexyl) phenyl] naphthalene 5,7-difluoro-6-cyano-2- [2-fluoro-4- (Trans-4-propylcyclohexyl) phenyl] naphthalene 5,7-difluoro-6-cyano-2- [2-fluoro-4- (trans-4-butylcyclohexyl) phenyl] naphthalene 5,7-difluoro-6-cyano -2- [2-Fluoro-4- (trans-4-pentylcyclohexyl) phenyl] naphthalene 5-fluoro-6-cyano-2- [2,6-difluoro-4- (trans-4-ethylcyclohexyl) phenyl] Naphthalene 5-fluoro-6-cyano-2- [2,6-difluoro-4- (trans-4-propyl Cyclohexyl) phenyl] naphthalene 5-fluoro-6-cyano-2- [2,6-difluoro-4- (trans-4-butylcyclohexyl) phenyl] naphthalene 5-fluoro-6-cyano-2- [2,6- Difluoro-4- (trans-4-pentylcyclohexyl) phenyl] naphthalene 5,7-difluoro-6-cyano-2- [2,6-difluoro-4- (trans-4-ethylcyclohexyl)
Phenyl] naphthalene 5,7-difluoro-6-cyano-2- [2,6-difluoro-4- (trans-4-propylcyclohexyl) phenyl] naphthalene 5,7-difluoro-6-cyano-2- [2, 6-difluoro-4- (trans-4-butylcyclohexyl)
Phenyl] naphthalene 5,7-difluoro-6-cyano-2- [2,6-difluoro-4- (trans-4-pentylcyclohexyl) phenyl] naphthalene 5-fluoro-6-cyano-2- [4- [2 -(Trans-4-propylcyclohexyl) ethyl] phenyl]
Naphthalene 5-fluoro-6-cyano-2- [4- [2- (trans-4-pentylcyclohexyl) ethyl] phenyl]
Naphthalene 5,7-difluoro-6-cyano-2- [4- [2-
(Trans-4-propylcyclohexyl) ethyl] phenyl] naphthalene 5,7-difluoro-6-cyano-2- [4- [2-
(Trans-4-pentylcyclohexyl) ethyl] phenyl] naphthalene 5-fluoro-6-cyano-2- [2-fluoro-4-
[2- (trans-4-propylcyclohexyl) ethyl] phenyl] naphthalene 5-fluoro-6-cyano-2- [2-fluoro-4-
[2- (trans-4-pentylcyclohexyl) ethyl] phenyl] naphthalene 5,7-difluoro-6-cyano-2- [2-fluoro-4- [2- (trans-4-propylcyclohexyl) ethyl] phenyl] Naphthalene 5,7-difluoro-6-cyano-2- [2-fluoro-4- [2- (trans-4-pentylcyclohexyl) ethyl] phenyl] naphthalene 5-fluoro-6-cyano-2- [2,6 -Difluoro-4- [2- (trans-4-propylcyclohexyl) ethyl] phenyl] naphthalene 5-fluoro-6-cyano-2- [2,6-difluoro-4- [2- (trans-4-pentylcyclohexyl) ) Ethyl] phenyl] naphthalene 5,7-difluoro-6-cyano-2- [2,6-difluoro-4- [2- Trans-4-propylcyclohexyl) ethyl] phenyl] naphthalene 5,7-difluoro-6-cyano-2- [2,6-difluoro-4- [2- (trans-4-pentylcyclohexyl) ethyl] phenyl] naphthalene 4 '-Ethyl-4- (5-fluoro-6-cyanonaphthalen-2-yl) biphenyl 4'-propyl-4- (5-fluoro-6-cyanonaphthalen-2-yl) biphenyl 4'-butyl-4- (5-fluoro-6-cyanonaphthalen-2-yl) biphenyl 4'-pentyl-4- (5-fluoro-6-cyanonaphthalen-2-yl) biphenyl 4 '-(3-buten-1-yl)- 4- (5-fluoro-6-cyanonaphthalen-2-yl) biphenyl 4'-ethyl-4- (5,7-difluoro-6-cyanonaphthalene-2 Yl) biphenyl 4'-propyl-4- (5,7-difluoro-6-cyanonaphthalen-2-yl) biphenyl 4'-butyl-4- (5,7-difluoro-6-cyanonaphthalen-2-yl) Biphenyl 4'-pentyl-4- (5,7-difluoro-6-cyanonaphthalen-2-yl) biphenyl 4 '-(3-buten-1-yl) -4- (5,7-difluoro-6-cyano Naphthalen-2-yl) biphenyl 2'-fluoro-4'-ethyl-4- (5-fluoro-
6-Cyanonaphthalen-2-yl) biphenyl 2'-fluoro-4'-propyl-4- (5-fluoro-6-cyanonaphthalen-2-yl) biphenyl 2'-fluoro-4'-butyl-4- ( 5-fluoro-
6-Cyanonaphthalen-2-yl) biphenyl 2'-fluoro-4'-pentyl-4- (5-fluoro-6-cyanonaphthalen-2-yl) biphenyl 2'-fluoro-4 '-(3-butene- 1-yl) -4
-(5-Fluoro-6-cyanonaphthalen-2-yl)
Biphenyl 2'-fluoro-4'-ethyl-4- (5,7-difluoro-6-cyanonaphthalen-2-yl) biphenyl 2'-fluoro-4'-propyl-4- (5,7-difluoro-6 -Cyanonaphthalen-2-yl) biphenyl 2'-fluoro-4'-butyl-4- (5,7-difluoro-6-cyanonaphthalen-2-yl) biphenyl 2'-fluoro-4'-pentyl-4- (5,7-difluoro-6-cyanonaphthalen-2-yl) biphenyl 2′-fluoro-4 ′-(3-buten-1-yl)-
4- (5,7-difluoro-6-cyanonaphthalene-2
-Yl) biphenyl 3,5-difluoro-4'-ethyl-4- (5-fluoro-6-cyanonaphthalen-2-yl) biphenyl 3,5-difluoro-4'-propyl-4- (5-fluoro- 6-Cyanonaphthalen-2-yl) biphenyl 3,5-difluoro-4'-butyl-4- (5-fluoro-6-cyanonaphthalen-2-yl) biphenyl 3,5-difluoro-4'-pentyl-4 -(5-Fluoro-6-cyanonaphthalen-2-yl) biphenyl 3,5-difluoro-4 '-(3-buten-1-yl)
-4- (5-Fluoro-6-cyanonaphthalen-2-yl) biphenyl 3,5-difluoro-4'-ethyl-4- (5,7-difluoro-6-cyanonaphthalen-2-yl) biphenyl 3, 5-difluoro-4'-propyl-4- (5,7-
Difluoro-6-cyanonaphthalen-2-yl) biphenyl 3,5-difluoro-4'-butyl-4- (5,7-difluoro-6-cyanonaphthalen-2-yl) biphenyl 3,5-difluoro-4 ' -Pentyl-4- (5,7-
Difluoro-6-cyanonaphthalen-2-yl) biphenyl 3,5-difluoro-4 '-(3-buten-1-yl) -4- (5,7-difluoro-6-cyanonaphthalen-2-yl) biphenyl 3-fluoro-4'-ethyl-4- (5-fluoro-6
-Cyanonaphthalen-2-yl) biphenyl 3-fluoro-4'-propyl-4- (5-fluoro-
6-Cyanonaphthalen-2-yl) biphenyl 3-fluoro-4′-butyl-4- (5-fluoro-6
-Cyanonaphthalen-2-yl) biphenyl 3-difluoro-4'-pentyl-4- (5-fluoro-
6-Cyanonaphthalen-2-yl) biphenyl 3-fluoro-4 ′-(3-buten-1-yl) -4-
(5-Fluoro-6-cyanonaphthalen-2-yl) biphenyl 3-fluoro-4'-ethyl-4- (5,7-difluoro-6-cyanonaphthalen-2-yl) biphenyl 3-fluoro-4'- Propyl-4- (5,7-difluoro-6-cyanonaphthalen-2-yl) biphenyl 3-fluoro-4'-butyl-4- (5,7-difluoro-6-cyanonaphthalen-2-yl) biphenyl 3 -Fluoro-4'-pentyl-4- (5,7-difluoro-6-cyanonaphthalen-2-yl) biphenyl 3-fluoro-4 '-(3-buten-1-yl) -4
-(5,7-Difluoro-6-cyanonaphthalene-2-
Yl) biphenyl (Example 8) 5-fluoro-6-cyano-2- (4-
Synthesis of propylphenyl) ethynylnaphthalene 10 g of 4-propyl-1-ethynylbenzene and 13.4 g of 5-fluoro-6-cyanonaphthalen-2-yl trifluoromethanesulfonate were dissolved in 50 ml of N, N-dimethylformamide (DMF). , Copper (I) iodide 50
mg and tetrakistriphenylphosphine palladium
(0) 100 mg was added and the mixture was stirred at room temperature for an hour. Toluene was added, insolubles were filtered off, and the mixture was washed with water and saturated saline. After evaporating the solvent, the residue was purified by silica gel column chromatography (hexane / ethyl acetate = 9/1), and further recrystallized from ethanol to give 5-fluoro-6-cyano-2- (4-propylphenyl) ethynyl. 7.3 g of naphthalene crystals were obtained.

In the same manner, the following compounds were obtained. 5-fluoro-6-cyano-2- (4-ethylphenyl) ethynylnaphthalene 5-fluoro-6-cyano-2- (4-butylphenyl) ethynylnaphthalene 5-fluoro-6-cyano-2- (4-pentyl) Phenyl) ethynylnaphthalene 5-fluoro-6-cyano-2- [4- (3-butene-
1-yl) phenyl] ethynylnaphthalene 5,7-difluoro-6-cyano-2- (4-ethylphenyl) ethynylnaphthalene 5,7-difluoro-6-cyano-2- (4-propylphenyl) ethynylnaphthalene 5, 7-difluoro-6-cyano-2- (4-butylphenyl) ethynylnaphthalene 5,7-difluoro-6-cyano-2- (4-pentylphenyl) ethynylnaphthalene 5,7-difluoro-6-cyano-2- [4- (3-Buten-1-yl) phenyl] ethynylnaphthalene 5-fluoro-6-cyano-2- (2-fluoro-4-
Ethylphenyl) ethynylnaphthalene 5-fluoro-6-cyano-2- (2-fluoro-4-
Propylphenyl) ethynylnaphthalene 5-fluoro-6-cyano-2- (2-fluoro-4-
Butylphenyl) ethynylnaphthalene 5-fluoro-6-cyano-2- (2-fluoro-4-
(Pentylphenyl) ethynylnaphthalene 5-fluoro-6-cyano-2- [2-fluoro-4-
(3-Buten-1-yl) phenyl] ethynylnaphthalene 5,7-difluoro-6-cyano-2- (2-fluoro-4-ethylphenyl) ethynylnaphthalene 5,7-difluoro-6-cyano-2- ( 2-fluoro-4-propylphenyl) ethynylnaphthalene 5,7-difluoro-6-cyano-2- (2-fluoro-4-butylphenyl) ethynylnaphthalene 5,7-difluoro-6-cyano-2- (2- Fluoro-4-pentylphenyl) ethynylnaphthalene 5,7-difluoro-6-cyano-2- [2-fluoro-4- (3-buten-1-yl) phenyl] ethynylnaphthalene 5-fluoro-6-cyano-2 -(2,6-difluoro-4-ethylphenyl) ethynylnaphthalene 5-fluoro-6-cyano-2- (2,6-difluoro B-4-Propylphenyl) ethynylnaphthalene 5-fluoro-6-cyano-2- (2,6-difluoro-4-butylphenyl) ethynylnaphthalene 5-fluoro-6-cyano-2- (2,6-difluoro- 4-pentylphenyl) ethynylnaphthalene 5-fluoro-6-cyano-2- [2,6-difluoro-4- (3-buten-1-yl) phenyl] ethynylnaphthalene 5,7-difluoro-6-cyano-2 -(2,6-difluoro-4-ethylphenyl) ethynylnaphthalene 5,7-difluoro-6-cyano-2- (2,6-difluoro-4-propylphenyl) ethynylnaphthalene 5,7-difluoro-6-cyano -2- (2,6-difluoro-4-butylphenyl) ethynylnaphthalene 5,7-difluoro-6-cyano-2- ( 2,6-difluoro-4-pentylphenyl) ethynylnaphthalene 5,7-difluoro-6-cyano-2- [2,6-difluoro-4- (3-buten-1-yl) phenyl] ethynylnaphthalene 5-fluoro -6-cyano-2- [4- (trans-4
-Propylcyclohexyl) phenyl] ethynylnaphthalene 5-fluoro-6-cyano-2- [4- (trans-4
-Butylcyclohexyl) phenyl] ethynylnaphthalene 5-fluoro-6-cyano-2- [4- (trans-4
-Pentylcyclohexyl) phenyl] ethynylnaphthalene 5,7-difluoro-6-cyano-2- [4- (trans-4-propylcyclohexyl) phenyl] ethynylnaphthalene 5,7-difluoro-6-cyano-2- [4- (Trans-4-butylcyclohexyl) phenyl] ethynylnaphthalene 5,7-difluoro-6-cyano-2- [4- (trans-4-pentylcyclohexyl) phenyl] ethynylnaphthalene 5-fluoro-6-cyano-2- [ 2,6-difluoro-4- (trans-4-propylcyclohexyl) phenyl] ethynylnaphthalene 5-fluoro-6-cyano-2- [2,6-difluoro-4- (trans-4-butylcyclohexyl) phenyl] ethynyl Naphthalene 5-fluoro-6-cyano-2- [2 6-difluoro-4- (trans-4-pentylcyclohexyl) phenyl] ethynylnaphthalene 5,7-difluoro-6-cyano-2- [2,6-difluoro-4- (trans-4-propylcyclohexyl) phenyl] ethynyl Naphthalene 5,7-difluoro-6-cyano-2- [2,6-difluoro-4- (trans-4-butylcyclohexyl)
Phenyl] ethynylnaphthalene 5,7-difluoro-6-cyano-2- [2,6-difluoro-4- (trans-4-pentylcyclohexyl) phenyl] ethynylnaphthalene (Example 9) 4-fluoro 4-pentylbenzoic acid -6
-Cyanonaphthalen-2-yl (formula (I-
13.6 g of 4-pentylbenzoic acid chloride and 10 g of 5-fluoro-6-cyanonaphthalen-2-ol were dissolved in 50 ml of dichloromethane, and 29 ml of pyridine was added.
Stirred at room temperature for 1 hour. Water and toluene were added, and the toluene layer was washed successively with diluted hydrochloric acid, water, and saturated saline. After evaporating the solvent, the residue was purified by silica gel column chromatography (hexane / ethyl acetate = 9/1), and further recrystallized from ethanol to give a crystal of 5-fluoro-6-cyanonaphthalen-2-yl 4-pentylbenzoate. 15.4 g were obtained.

In the same manner, the following compounds were obtained. 5-Fluoro-6-cyanonaphthalen-2-yl 4-propylbenzoate 5-fluoro-6-cyanonaphthalen-2-yl 4-butylbenzoate 5-fluoro-6-cyanonaphthalene-2-yl 4-heptylbenzoate Yl 4- (3-buten-1-yl) benzoic acid 5-fluoro-
6-Cyanonaphthalen-2-yl 4-vinylcyclohexanecarboxylic acid 5-fluoro-6
-Cyanonaphthalen-2-yl 4-propylcyclohexanecarboxylic acid 5-fluoro-
6-cyanonaphthalen-2-yl 4-butylcyclohexanecarboxylic acid 5-fluoro-6
-Cyanonaphthalen-2-yl 4-pentylcyclohexanecarboxylic acid 5-fluoro-
6-Cyanonaphthalen-2-yl (formula (I-
7) Compound) 4-heptylcyclohexanecarboxylic acid 5-fluoro-
6-cyanonaphthalen-2-yl 4- (3-buten-1-yl) cyclohexanecarboxylic acid 5-fluoro-6-cyanonaphthalen-2-yl 5-propylbenzoic acid 5,7-difluoro-6-cyanonaphthalene- 5,7-Difluoro-6-cyanonaphthalen-2-yl 2-butyl 4-butylbenzoate 5,7-difluoro-6-cyanonaphthalen-2-yl 4-pentylbenzoate 5,7-heptylbenzoic acid Difluoro-6-cyanonaphthalen-2-yl 4- (3-buten-1-yl) benzoic acid 5,7-difluoro-6-cyanonaphthalen-2-yl 2-fluoro-4-propylbenzoic acid 5-fluoro- 6
-Cyanonaphthalen-2-yl 2-fluoro-4-butylbenzoic acid 5-fluoro-6-
Cyanonaphthalen-2-yl 2-fluoro-4-pentylbenzoic acid 5-fluoro-6
-Cyanonaphthalen-2-yl 2-fluoro-4-heptylbenzoic acid 5-fluoro-6
-Cyanonaphthalen-2-yl 2-fluoro-4- (3-buten-1-yl) benzoic acid 5-fluoro-6-cyanonaphthalen-2-yl 2-fluoro-4-propylbenzoic acid 5,7-difluoro -5-Cyanonaphthalen-2-yl 2,7-difluoro-6-cyanonaphthalen-2-yl 2-fluoro-4-butylbenzoate 5,7-difluoro-6-cyano 2-fluoro-4-pentylbenzoate Naphthalen-2-yl 5,7-difluoro-6-cyanonaphthalen-2-yl 2-fluoro-4-heptylbenzoate 5,7-difluoro 2-fluoro-4- (3-buten-1-yl) benzoate -6-Cyanonaphthalen-2-yl 2,6-difluoro-4-propylbenzoic acid 5-fluoro-6-cyanonaphthalen-2-yl 2,6-difluoro- -Butylbenzoic acid 5-fluoro-6-cyanonaphthalen-2-yl 2,6-difluoro-4-pentylbenzoic acid 5-Fluoro-6-cyanonaphthalen-2-yl 2,6-difluoro-4-heptylbenzoic acid 5-fluoro-6-cyanonaphthalen-2-yl 2,6-difluoro-4- (3-buten-1-yl) benzoic acid 5-fluoro-6-cyanonaphthalen-2-yl 2,6-difluoro-4 5,7-Difluoro-6-cyanonaphthalen-2-yl-propylbenzoate 2,7-difluoro-6-cyanonaphthalen-2-yl 2,6-difluoro-4-butylbenzoate 2,6-difluoro-4 5,7-difluoro-6-cyanonaphthalen-2-yl 2,6-difluoro-4-heptylbenzoic acid 5,7-difluoro-6-pentylbenzoic acid Ano naphthalen-2-yl 2,6-difluoro-4- (3-buten-1-yl) benzoic acid 5,7-difluoro-6-cyano-naphthalene-2,6
-Yl 4- (trans-4-ethyl) cyclohexylbenzoic acid 5-fluoro-6-cyanonaphthalen-2-yl 4- (trans-4-propyl) cyclohexylbenzoic acid 5-fluoro-6-cyanonaphthalen-2-yl 4- (Trans-4-butyl) cyclohexylbenzoic acid 5-fluoro-6-cyanonaphthalen-2-yl 4- (trans-4-pentyl) cyclohexylbenzoic acid 5-fluoro-6-cyanonaphthalen-2-yl 4- 5,7-Difluoro-6-cyanonaphthalen-2-yl (trans-4-ethyl) cyclohexylbenzoate 5,7-difluoro-6-cyanonaphthalen-2-yl 4- (trans-4-propyl) cyclohexylbenzoate 4- (trans-4-butyl) cyclohexylbenzoic acid 5,7-difluoro-6- Cyanonaphthalen-2-yl 4- (trans-4-pentyl) cyclohexylbenzoic acid 5,7-difluoro-6-cyanonaphthalen-2-yl 2-fluoro-4- (trans-4-ethyl) cyclohexylbenzoic acid 5- Fluoro-6-cyanonaphthalene-
5-fluoro-6-cyanonaphthalen-2-yl 2-fluoro-2- (trans-4-propyl) cyclohexylbenzoate 5-fluoro-2-fluoro-2- (trans-4-butyl) cyclohexylbenzoate -6-cyanonaphthalene-
2-yl 2-fluoro-4- (trans-4-pentyl) cyclohexylbenzoic acid 5-fluoro-6-cyanonaphthalen-2-yl 2-fluoro-4- (trans-4-ethyl) cyclohexylbenzoic acid 5,7 -Difluoro-6-cyanonaphthalen-2-yl 2-fluoro-4- (trans-4-propyl) cyclohexylbenzoic acid 5,7-difluoro-6-cyanonaphthalen-2-yl 2-fluoro-4- (trans- 5,7-Difluoro-6-cyanonaphthalen-2-yl 4-butyl) cyclohexylbenzoate 5,7-difluoro-6-cyanonaphthalene-2-yl 2-fluoro-4- (trans-4-pentyl) cyclohexylbenzoate Yl 2,6-difluoro-4- (trans-4-ethyl) cyclohexylbenzoic acid 5-fluoro- - cyano-2-yl 2,6-difluoro-4- (trans-4-propyl)
5-fluoro-6-cyanonaphthalen-2-yl cyclohexylbenzoate 2,6-difluoro-4- (trans-4-butyl) cyclohexylbenzoate 5-fluoro-6-cyanonaphthalen-2-yl 2,6-difluoro -4- (trans-4-pentyl)
5-fluoro-6-cyanonaphthalen-2-yl cyclohexylbenzoate 5,7-difluoro-6-cyanonaphthalen-2-yl 2,6-difluoro-4- (trans-4-ethyl) cyclohexylbenzoate 2,6 -Difluoro-4- (trans-4-propyl)
5,7-Difluoro-6-cyanonaphthalen-2-yl cyclohexylbenzoate 5,7-difluoro-6-cyanonaphthalen-2-yl 2,6-difluoro-4- (trans-4-butyl) cyclohexylbenzoate 2 , 6-Difluoro-4- (trans-4-pentyl)
5,7-Difluoro-6-cyanonaphthalen-2-yl cyclohexylbenzoate (Example 10) Preparation of liquid crystal composition General-purpose n-type host liquid crystal (H)

[0132]

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(The cyclohexane ring has a trans configuration.) Shows a nematic phase at 72.5 ° C. or lower. This host liquid crystal (H) was filled in a TN cell having a cell thickness of 8.0 μm to prepare a liquid crystal element.

The measurement of the electro-optical characteristics was as follows. Dielectric anisotropy (Δε) -1.3 Refractive index anisotropy (Δn) 0.085 Here, the response time is the response time at the time of voltage application where the rise time (τr) and the fall time (τd) are equal It is.

Next, 80% by weight of the host liquid crystal (H) and the formula (I-1) obtained in Example 1 were used.

[0136]

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When a nematic liquid crystal composition (M-1) comprising 20% by weight of the compound (I) was prepared, the maximum temperature of the liquid crystal phase (T _NI ) was 78.9 ° C., an increase of 6 ° C. or more. After leaving (M-1) at 150 ° C. for 20 hours, its T
_NI was measured, and there was almost no change at 78.5 ° C. as compared to before heating. Irradiation with ultraviolet rays for 20 hours showed no change in T _NI . This (M-1) was allowed to stand at -20 ° C for 2 weeks, but no crystal precipitation or phase separation was observed. Next, it was cooled to −60 ° C. for crystallization, and its melting point (T _CN ) was measured.
Met.

Next, a cell was filled in the same manner as in (M-1) to prepare a liquid crystal element, and its electro-optical characteristics were measured. The results were as follows. Nematic phase maximum temperature (T _NI ) 78.9 ° C. Dielectric anisotropy (Δε) 3.2 Threshold voltage (Vth) 2.14 V Response time (τ) 40.0 ms Refractive index anisotropy (Δn) 0. 106 The host liquid crystal (H) is n-type and does not respond, but (M
In -1), the dielectric constant anisotropy (Δε) was increased to 3.2 by containing 20% by weight of the compound of the formula (I-1), and a high-speed response of 40 ms was possible. Further, it can be seen that the refractive index anisotropy (Δn) has also increased. Comparative Example 1 80% by weight of the host liquid crystal (H) and the compound of the formula (I-
Formula (A), which is a 6-cyanonaphthalene derivative having a structure relatively similar to the compound of 1) but containing no fluorine atom

[0139]

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A nematic liquid crystal composition (MA) consisting of 20% by weight of the compound was prepared. A liquid crystal element was prepared in the same manner, and its electro-optical characteristics were measured. The results were as follows.

Nematic phase maximum temperature (T _NI ) 81.2 ° C. Dielectric anisotropy (Δε) 2.2 Threshold voltage (Vth) 2.68 V Response time (τ) 37.5 ms Refractive index anisotropy (Δn) In 0.108 (MA), T _NI is increased by about 2 ° C. as compared with (M−1), and the response is slightly faster. However, Δε
Is considerably reduced, and as a result, the threshold voltage (Vth) is greatly increased. When (MA) was similarly left at -20 ° C, crystals precipitated within one week. Therefore, it can be seen that the compound of the formula (A) is inferior to the compound of the formula (I-1) according to the present invention in terms of lowering the driving voltage and compatibility with general-purpose liquid crystals. Comparative Example 2 80% by weight of the host liquid crystal (H) and the compound represented by the formula (I-
Formula (B), which is a 3-fluoro-4-cyanobenzene derivative having a structure relatively similar to the compound of 1) but not containing a naphthalene skeleton

[0142]

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A nematic liquid crystal composition (MB) consisting of 20% by weight of the compound was prepared. A liquid crystal element was prepared in the same manner, and its electro-optical characteristics were measured. The results were as follows.

Nematic phase upper limit temperature (T _NI ) 58.5 ° C. Dielectric anisotropy (Δε) 3.6 Threshold voltage (Vth) 2.2 V Response time (τ) 36.0 ms Refractive index anisotropy (Δn) It can be seen that Δε of 0.084 (M−B) is greater than (M−1) and Vth is therefore more effectively reduced. However, its T _NI is about 20 compared to (M-1).
° C has also dropped. Therefore, it can be seen that the compound of the formula (B) has a low liquid crystallinity and does not reach the compound of the formula (I-1) related to the present invention in securing a wide temperature range.

As described above, the compound of the formula (I-1) is excellent in compatibility with other liquid crystal compounds, has a high nematic phase upper limit temperature, and its addition greatly increases the dielectric anisotropy to increase the threshold value. Equations (A) and (2) which are relatively similar to the conventionally known structures in that the voltage can be reduced, and the high-speed response and the anisotropy of the refractive index can be increased. It is clear that it is even better when compared to the compound of formula (B).

[0146]

The compound represented by the general formula (I) according to the present invention can be easily produced industrially as shown in Examples, and is chemically stable to heat, light, water and the like. It is. In addition, it has excellent liquid crystal properties and excellent compatibility with currently used liquid crystal compounds or compositions. Further, the addition thereof has the advantages that the dielectric anisotropy can be greatly increased and the threshold voltage thereof can be reduced, and that the high-speed response and the anisotropy of the refractive index can be increased. Therefore, a) the nematic phase temperature range is wide, b) the threshold voltage is low, low voltage driving is possible, and c) the liquid crystal composition capable of high-speed response is very useful and practical. .

Claims (9)

[Claims] 1. A compound of the general formula (I) (In the formula, R represents an alkyl group having 1 to 12 carbon atoms, an alkoxyl group or an alkoxylalkyl group having 2 to 12 carbon atoms, an alkenyl group or an alkenyloxy group, and ring A represents trans-1,4-cyclo Xylene group,
Represents a 1,4-phenylene group, a 2-fluoro-1,4-phenylene group or a 2,6-difluoro-1,4-phenylene group, and ring B is a trans-1,4-cyclohexylene group; Represents a phenylene group, a 2-fluoro-1,4-phenylene group, a 2,6-difluoro-1,4-phenylene group or a single bond, and L and M each independently represent -C
_{H 2 CH 2 -, - CH} 2 O -, - OCH 2 -, - COO-,
_{-OCO -, - CF 2 O -} , - OCF 2 -, - CH 2 CH 2
CH ₂ CH ₂ —, —CF ＝ CF—, —C≡C—, or a single bond. When ring B represents a single bond, M represents a single bond. X ^{1 to} X ³ each independently represent a hydrogen atom or a fluorine atom, and at least one of them represents a fluorine atom. A novel liquid crystalline compound which is a fluorine-substituted 6-cyanonaphthalene derivative represented by the following formula: 2. The compound according to claim 1, wherein in the formula (I), X ² represents a fluorine atom. 3. In the general formula (I), L and M represent —C
_{H 2 CH 2 -, - COO} -, - C≡C- or claim 1 or 2 A compound according to where represents a single bond. 4. The compound of claim 1, wherein at least one of L and M in formula (I) represents a single bond.
A compound as described. 5. The method according to claim 1, wherein in the general formula (I), R represents a linear alkyl group having 1 to 7 carbon atoms.
The compound according to 2, 3, or 4. 6. A liquid crystal composition comprising the compound represented by the general formula (I) according to claim 1. 7. The liquid crystal composition according to claim 6, which is used for STN display. 8. A liquid crystal device comprising the liquid crystal composition according to claim 6 as a constituent element. 9. An ST using the liquid crystal composition according to claim 7.
N liquid crystal display element.