JP5740840B2 - Azobenzene derivative and liquid crystal composition containing the same - Google Patents

Description

  The present invention relates to a compound having both an azobenzene structure and a fluorine-substituted tolan structure, which is useful as an organic electronic material, medical pesticide, and particularly as a nematic liquid crystal material for electro-optical liquid crystal display.

  Liquid crystal display elements are used in various measuring instruments, automobile panels, word processors, electronic notebooks, printers, computers, televisions, watches, advertisement display boards, as well as watches and calculators. Typical liquid crystal display methods include TN (twisted nematic) type, STN (super twisted nematic) type, vertical alignment type using TFT (thin film transistor), and IPS (in-plane switching) type. Etc. In recent years, in these liquid crystal display elements, there is a tendency to achieve higher-speed driving by narrowing the cell gap (d) of the liquid crystal cell. Here, there is a constraint that the value (retardation) of the product (d × Δn) of the cell gap and the refractive index anisotropy (Δn) must be optimized. For this reason, if the cell gap is narrowed (d is decreased), the value of Δn must be increased. Thus, it is necessary to increase the Δn value of the liquid crystal composition, and a liquid crystal compound having a larger Δn value than the existing liquid crystal compounds is demanded.

  On the other hand, development of a cholesteric liquid crystal display element is underway as a new display method. A polarizing plate is required to configure the conventional display element described above, and a color filter is required to realize color display, but the presence of the polarizing plate not only reduces the light use efficiency, The viewing angle characteristics are adversely affected, and the presence of a color filter has a problem that the light use efficiency is lowered. This cholesteric liquid crystal display element displays light by selectively reflecting light having a wavelength corresponding to the helical pitch of the cholesteric liquid crystal from the circularly polarized light component contained in the external light. The drawbacks of the liquid crystal display element can be improved.

  In a cholesteric liquid crystal display element, a selective reflection state in a planar state in which the spiral axis is usually perpendicular to the substrate is used. At this time, it is known that the half-value width (Δλ) of the selectively reflected light is represented by the product of Δn and the natural pitch (P), and has a large refractive index anisotropy in order to realize a bright display. Requires a compound. Therefore, development of a liquid crystal compound exhibiting a larger Δn value is also strongly desired for a liquid crystal composition for a cholesteric liquid crystal display element.

  A typical example of a liquid crystal compound exhibiting a large Δn value is a tolan compound. The compound represented by the formula (A) has a Δn value of 0.178 (Patent Document 1). The value of Δn can generally be increased by expanding the conjugated system in the molecular structure. For this reason, a compound represented by the formula (B) in which an aromatic ring is introduced into the compound represented by the formula (A) to further increase Δn was developed, and Δn showed 0.384 (Patent Document 2). ).

  Further, an azine-based compound represented by the formula (C) conjugated in a wide range has been developed, and this compound has Δn of 0.340 (Patent Document 3).

  However, even these conventionally developed compounds are insufficient to meet the above-mentioned demands, and it has been demanded to meet the demand for further higher Δn. In order to achieve higher Δn, it is effective to introduce an aromatic ring into the compound in order to further expand the conjugated system. However, increasing the number of aromatic rings increases the rigidity of the molecule and facilitates crystallization. It becomes. For this reason, when a liquid crystal compound having an increased number of aromatic rings is added to the liquid crystal composition, crystals of these compounds are precipitated from the liquid crystal composition during use, which causes display defects of the liquid crystal display element. In addition, if it becomes easy to be crystallized, the nematic phase expression temperature range becomes narrow, so it cannot be used as a component of a practical liquid crystal composition.

  As described above, when an attempt is made to increase the value of Δn, compatibility with other liquid crystal materials and liquid crystal properties are lowered, so that it is not easy to develop a material satisfying all of these.

  Both the azobenzene structure and the tolan structure are known as structures exhibiting a large Δn, and the compound represented by the formula (D) as a material having both these structures is a liquid crystal material having good solubility in the host liquid crystal. It has been reported (Patent Document 4). However, this compound has been developed as a pigment to be added to the liquid crystal composition, and there is no description regarding basic physical properties as a liquid crystal material such as Δn, and is added in a large amount to the liquid crystal composition. There is no description about improving the compatibility. Therefore, when the present inventors actually synthesized this compound and measured the physical properties, the compatibility with other liquid crystal materials exhibiting a large Δn was low, and it was expressed by the formula (D) from the liquid crystal composition. As a result, it was clarified that the compound immediately precipitated and could not be put into practical use.

  In addition, as a method for improving the compatibility with other liquid crystal materials, a method of introducing fluorine atoms in a molecular uniaxial direction is known. For example, a compound represented by formulas (E) and (F) in which a fluorine atom is introduced into a compound represented by formula (D) has been reported (Non-patent Document 1). Although there is no description regarding Δn for these compounds, they are expected to show large values. However, the phase transition of the compound represented by the formula (E) is Cr 72.9 SmC 109.0 N 184.8 Iso, and the phase transition of the compound represented by the formula (F) is Cr 102.6 SmB 155. .2 N 215.3 Iso, indicating that it is likely to exhibit a smectic phase. In general, when a material that easily exhibits a smectic phase is added to the liquid crystal composition, the smectic phase that appears in a lower temperature region than the nematic phase is stabilized, the lower limit temperature of the nematic phase is increased, and the nematic phase temperature range is narrowed. For this reason, as a liquid crystal material used for a liquid crystal display element for driving a nematic liquid crystal, a material which does not show a smectic phase and shows a nematic phase in a wide temperature range is preferable.

  The smectic phase is a liquid crystal layer having a layer structure, in which the directions of molecules are aligned in the major axis direction, and the mutual coordination between the neighbors is regular. For this reason, the influence which the substituent which protruded from the major axis direction has on the stability of the smectic layer becomes large. If the compound represented by the formula (D) can improve the compatibility with other liquid crystal materials, the value of Δn is large, so it is very promising as a constituent component of the liquid crystal composition. However, until now, development has not been performed from such a viewpoint.

JP-A-61-5031 JP-A-60-152427 JP-A-11-71338 JP-A-2-56456

Liquid Crystals, 2001, 28, 3, 375-379.

  The problem to be solved by the present invention is to provide a material excellent in compatibility with other liquid crystal materials and nematic liquid crystal while realizing a high Δn, and a liquid crystal composition comprising the compound as a constituent member. Is to provide.

  In order to solve the above-mentioned problems, the inventors of the present invention have studied the synthesis of various compounds. As a result, the compounds can be effectively solved by using a compound having both an azobenzene moiety and a tolan moiety and further introducing a fluorine atom into the tolan moiety. And the present invention has been completed.

  The present invention provides a general formula (1)

Wherein R ¹ and R ² are each independently a fluorine atom, a chlorine atom, a cyano group, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. Or an alkenyloxy group having 2 to 12 carbon atoms, wherein each one or more hydrogen atoms may be independently substituted with fluorine atoms, and each —CH ₂ — group independently contains an oxygen atom. as two do not continuously bound more -O -, - CO -, - COO- or -OCO- may be substituted by, or ^{R 1} and ^{R 2} are each independently ^R 3 -Z ⁴ -(In the formula, R ³ represents an alkyl group having 1 to 12 carbon atoms or an alkenyl group having 2 to 12 carbon atoms, and one or more hydrogen atoms in the group may be independently substituted with fluorine atoms. , ^{Z 4} represents -CH = CH- or -C≡C- Represents a) not represent a substituent R ¹ and R ² are both fluorine atoms, selected from a chlorine atom and a cyano group,
Z ¹ , Z ² and Z ³ are each independently a single bond, —OCH ₂ —, —CH ₂ O—, —C ₂ H ₄ —, —C ₄ H ₈ —, —COO—, —OCO—, — CH═CH—, —CF═CF—, —CF ₂ O—, —OCF ₂ —, —CF ₂ CF ₂ — or —C≡C—
A ¹ , A ³ , A ⁴ , A ⁵ and A ⁶ each independently represents a 1,4-phenylene group, a naphthalene-1,4-diyl group or a naphthalene-2,6-diyl group, and A ¹ , A ³ , hydrogen atoms in A ⁴ , A ⁵ and A ⁶ may be each independently substituted with a halogen atom, and one or more non-adjacent ones in A ¹ , A ³ , A ⁴ , A ⁵ and A ⁶ -CH = may be replaced by -N =
A ² represents a 1,4-phenylene group in which two hydrogen atoms not on adjacent carbons are substituted with fluorine atoms;
m, n, and p each independently represent 0 or 1, but m + n + p represents 0 or 1. And a liquid crystal composition containing the compound.

  The novel liquid crystal compound represented by the general formula (1) provided by the present invention is stable against heat, light, etc., has excellent liquid crystallinity, and can be easily produced industrially. The obtained compound represented by the general formula (1) has a very large Δn and exhibits a wide liquid crystal phase temperature range.

  Therefore, when added to a liquid crystal material for a cholesteric liquid crystal display element that requires a large Δn, the characteristics can be improved without causing problems such as precipitation. Useful for.

In General Formula (1), R ¹ and R ² may be the same or different, but an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, and 1 to 12 carbon atoms. An alkoxyl group, an alkenyloxy group having 2 to 12 carbon atoms, a fluorine atom, a cyano group, or R ³ —Z ⁴ — is preferable. In particular, in order to improve the solubility, an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alkoxyl group having 1 to 8 carbon atoms, an alkenyloxy group having 2 to 8 carbon atoms, a fluorine atom or R ^3- Z ⁴ -is preferred, and in order to improve liquid crystallinity, an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alkoxyl group having 1 to 8 carbon atoms, and an alkenyl having 2 to 8 carbon atoms group or R ³ -Z 4 ^- is preferable, in order to increase the value of Δε is fluorine atom or a cyano group are preferred, and in order to increase the Δn is R ³ -Z 4 ^- are preferred.

Z ¹ , Z ² and Z ³ are each independently a single bond, —OCH ₂ —, —CH ₂ O—, —C ₂ H ₄ —, —CH═CH—, —CF ₂ O—, —OCF ₂ —. Alternatively, —C≡C— is preferable, and a single bond, —OCH ₂ —, —CH ₂ O—, —CF ₂ O—, —OCF ₂ —, or —C≡C— is more preferable.

A ¹ , A ³ , A ⁴ , A ⁵ and A ⁶ are each independently a unsubstituted 1,4-phenylene group which may be substituted with one or more fluorine atoms, naphthalene-2,6- A diyl group and a naphthalene-1,4-diyl group are preferred, and —CH═ in these structures may be substituted with —N═, and may be unsubstituted or substituted with one or more fluorine atoms. A good 1,4-phenylene group is preferred, and an unsubstituted 1,4-phenylene group is more preferred.

A ² is preferably a 2,6-difluoro-1,4-phenylene group or a 3,5-difluoro-1,4-phenylene group.

  Since Δn exhibits a large value when the number of aromatic rings is large, m, n, and p are preferably 1 in order to increase Δn. However, when the number of aromatic rings is large, the phase with other liquid crystal materials is large. Solubility will decrease. For this reason, it is preferable that any two of m, n, and p are 0, and it is more preferable that all are 0.

In the general formula (1), various types of compounds may be included depending on the selection of R ^{1 to} R ² , A ^{1 to} A ⁶ , Z ^{1 to} Z ³ , m, n, and p. In these, each compound represented by the following general formula (1-1)-general formula (1-57) is preferable.

(In the formula, R ^a and R ^b are each independently an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkoxyl group having 1 to 12 carbon atoms, or an alkenyloxy having 2 to 12 carbon atoms. Group or R ^c —Z ^a — (wherein R ^c represents an alkyl group having 1 to 12 carbon atoms or an alkenyl group having 2 to 12 carbon atoms, and Z ⁴ represents —CH═CH— or —C≡C—). )
If the content of the compound represented by the general formula (1) is small in the liquid crystal composition of the present invention, the effect does not appear. Therefore, the lower limit value in the composition is 1% by mass (hereinafter,% in the composition is mass). %)), Preferably 2% or more, more preferably 5% or more. Further, since a large content causes problems such as precipitation, the upper limit value is preferably 50% or less, more preferably 30% or less, and even more preferably 20% or less. % Or less is particularly preferable.

  In order to adjust the physical properties of the liquid crystal composition, a compound having no liquid crystal phase can be added as needed in addition to the compound having a liquid crystal phase.

  Thus, as a preferable representative example of the nematic liquid crystal compound that can be used by mixing with the compound represented by the general formula (1), in the composition provided by the present invention, the general formula is used as the first component. Although at least one compound represented by (1) is contained, it is preferable to contain at least one of the following second to fourth components as other components.

  That is, the second component is a so-called fluorine-based (halogen-based) p-type liquid crystal compound, and is composed of compounds represented by the following general formulas (A1) to (A3).

In the above formula, R ^b represents an alkyl group having 1 to 12 carbon atoms, which may be linear or have a methyl or ethyl branch, and has a 3- to 6-membered cyclic structure. Any —CH ₂ — present in the group may be —O—, —CH═CH—, —CH═CF—, —CF═CH—, —CF═CF— or —C≡C. Any hydrogen atom present in the group may be substituted by a fluorine atom or a trifluoromethoxy group, but a linear alkyl group having 1 to 7 carbon atoms, a carbon atom A linear 1-alkenyl group having 2 to 7 carbon atoms, a linear 3-alkenyl group having 4 to 7 carbon atoms, and a terminal group having 1 to 5 carbon atoms substituted with an alkoxyl group having 1 to 3 carbon atoms. Alkyl groups are preferred. Further, when asymmetric carbon is generated by branching, the compound may be optically active or racemic.

Ring A, Ring B, and Ring C may each independently be substituted with a trans-1,4-cyclohexylene group, a transdecahydronaphthalene-trans-2,6-diyl group, or one or more fluorine atoms. A good 1,4-phenylene group, a naphthalene-2,6-diyl group optionally substituted by one or more fluorine atoms, a tetrahydronaphthalene-2,6-optionally substituted by one or more fluorine atoms Diyl group, 1,4-cyclohexenylene group optionally substituted by a fluorine atom, 1,3-dioxane-trans-2,5-diyl group, pyrimidine-2,5-diyl group or pyridine-2,5 -Represents a diyl group, but may be a trans-1,4-cyclohexylene group, a transdecahydronaphthalene-trans-2,6-diyl group, or a naphth optionally substituted by a fluorine atom The alkylene-2,6-diyl group or one to two fluorine atoms may be substituted 1,4-phenylene group is preferred. In particular, when ring B is a trans-1,4-cyclohexylene group or a transdecahydronaphthalene-trans-2,6-diyl group, ring A may be a trans-1,4-cyclohexylene group. Preferably, when ring C is a trans-1,4-cyclohexylene group or a transdecahydronaphthalene-trans-2,6-diyl group, ring B and ring A are trans-1,4-cyclohexylene groups. Preferably there is. In (A3), ring A is preferably a trans-1,4-cyclohexylene group.
L ^a , L ^b and L ^c are each a linking group and each independently represents a single bond, an ethylene group (—CH ₂ CH ₂ —), a 1,2-propylene group (—CH (CH ₃ ) CH ₂ — and _{-CH 2 CH (CH 3) -} ), 1,4- butylene _{group, -COO -, - OCO -,} - OCF 2 -, - CF 2 O -, - CH = CH -, - CH = CF -, - CF═CH—, —CF═CF—, —C≡C— or —CH═NN═CH—, each represents a single bond, ethylene group, 1,4-butylene group, —COO—, —OCF ₂ —, —CF ₂ O—, —CF═CF— or —C≡C— are preferred, and a single bond or an ethylene group is particularly preferred. Further, it is preferable that at least one of (A2) represents a single bond and at least two of (A3) represent a single bond.

  Ring Z is an aromatic ring and can be represented by the following general formulas (La) to (Lc).

In the formula, Y ^{a to} Y _j each independently represent a hydrogen atom or a fluorine atom. In (IXa), at least one of Y ^a and Y ^b is preferably a fluorine atom, and in (Lb), At least one of Y ^{d to} Y ^f is preferably a fluorine atom, and Y ^d is more preferably a fluorine atom.

Terminal group P ^a represents a fluorine atom, a chlorine atom, trifluoromethoxy group, difluoromethoxy group, trifluoromethyl group or difluoromethyl group or 2 or more carbon atoms substituted by fluorine atoms 2 or 3 of the alkoxyl group, an alkyl Represents a group, an alkenyl group or an alkenyloxy group, preferably a fluorine atom, a trifluoromethoxy group or a difluoromethoxy group, and particularly preferably a fluorine atom.

  In (A2), the compound of the general formula (I) of the present invention is excluded.

  The third component is a so-called cyano p-type liquid crystal compound, which is composed of compounds represented by the following general formulas (B1) to (B3).

In the above formula, R ^c represents an alkyl group having 1 to 12 carbon atoms, which may be linear or have a methyl or ethyl branch, and has a 3- to 6-membered cyclic structure. Any —CH ₂ — present in the group may be —O—, —CH═CH—, —CH═CF—, —CF═CH—, —CF═CF— or —C≡C. Any hydrogen atom present in the group may be substituted by a fluorine atom or a trifluoromethoxy group, a linear alkyl group having 1 to 7 carbon atoms, a carbon atom A linear 1-alkenyl group having 2 to 7 carbon atoms, a linear 3-alkenyl group having 4 to 7 carbon atoms, and a terminal group having 1 to 5 carbon atoms substituted with an alkoxyl group having 1 to 3 carbon atoms. Alkyl groups are preferred. Further, when asymmetric carbon is generated by branching, the compound may be optically active or racemic.

  Ring D, Ring E and Ring F may be each independently substituted with a trans-1,4-cyclohexylene group, a transdecahydronaphthalene-trans-2,6-diyl group, or one or more fluorine atoms. A good 1,4-phenylene group, a naphthalene-2,6-diyl group optionally substituted by one or more fluorine atoms, a tetrahydronaphthalene-2,6-optionally substituted by one or more fluorine atoms Diyl group, 1,4-cyclohexenylene group optionally substituted by a fluorine atom, 1,3-dioxane-trans-2,5-diyl group, pyrimidine-2,5-diyl group or pyridine-2,5 -Represents a diyl group, but is substituted by a trans-1,4-cyclohexylene group, a transdecahydronaphthalene-trans-2,6-diyl group, a fluorine atom The good can have a naphthalene-2,6-diyl group or one to two fluorine atoms may be substituted 1,4-phenylene group is preferred. In particular, when ring E is a trans-1,4-cyclohexylene group or a transdecahydronaphthalene-trans-2,6-diyl group, ring D may be a trans-1,4-cyclohexylene group. Preferably, when Ring F is a trans-1,4-cyclohexylene group or a transdecahydronaphthalene-trans-2,6-diyl group, Ring D and Ring E are trans-1,4-cyclohexylene groups. Preferably there is. In (B3), ring D is preferably a trans-1,4-cyclohexylene group.

L ^d , ^Le and L ^f are each a linking group and each independently represents a single bond, an ethylene group (—CH ₂ CH ₂ —), a 1,2-propylene group (—CH (CH ₃ ) CH ₂ — and ) —CH ₂ CH (CH ₃ ) —), 1,4-butylene group, —COO—, —OCO—, —OCF ₂ —, —CF ₂ O—, —CH═CH—, —CH═CF—, —CF═CH—, —CF═CF—, —C≡C—, —OCH ₂ —, —CH ₂ O— or —CH═NN═CH— represents a single bond, ethylene group, —COO—, —OCF ₂ —, —CF ₂ O—, —CF═CF— or —C≡C— are preferred, and a single bond, an ethylene group or —COO— is particularly preferred. Further, it is preferable that at least one of them in (B2) represents a single bond in (B3).

Ring Y is an aromatic ring and can be represented by the following general formulas (L ^d ) to (L ^f ).

In the formula, Y ^{h to} Y ⁿ each independently represent a hydrogen atom or a fluorine atom, and in (Le), Y ⁿ and Y ^o are preferably hydrogen atoms.
The terminal group Pa represents ^a cyano group (—CN), a cyanate group (—OCN) or —C≡CCN, and is preferably a cyano group.

  The fourth component is a so-called n-type liquid crystal having a dielectric anisotropy of about 0, and is composed of compounds represented by the following general formulas (C1) to (C3).

In the above formula, R ^d and R ^e each independently represents an alkyl group having 1 to 12 carbon atoms, and these may be linear or have a methyl or ethyl branch, and 3 to 6 Any —CH ₂ — present in the group may be —O—, —CH═CH—, —CH═CF—, —CF═CH—, —CF═. Any hydrogen atom present in the group may be replaced by CF- or -C≡C-, and may be substituted by a fluorine atom or a trifluoromethoxy group. A linear alkyl group, a linear 1-alkenyl group having 2 to 7 carbon atoms, a linear 3-alkenyl group having 4 to 7 carbon atoms, a linear alkoxyl group having 1 to 3 carbon atoms, or a terminal C 1-5 linear alkyl substituted with 1 to 3 alkoxy groups And at least one of them is a linear alkyl group having 1 to 7 carbon atoms, a linear 1-alkenyl group having 2 to 7 carbon atoms, or a linear 3-alkenyl group having 4 to 7 carbon atoms. Particularly preferred is a group.

  Ring G, Ring H, Ring I and Ring J are each independently a trans-1,4-cyclohexylene group, a transdecahydronaphthalene-trans-2,6-diyl group, one or two fluorine atoms, 1,4-phenylene group optionally substituted by a methyl group, naphthalene-2,6-diyl group optionally substituted by one or more fluorine atoms, substituted by 1 or 2 fluorine atoms A tetrahydronaphthalene-2,6-diyl group, a 1,4-cyclohexenylene group optionally substituted by 1 to 2 fluorine atoms, a 1,3-dioxane-trans-2,5-diyl group, Represents a pyrimidine-2,5-diyl group or a pyridine-2,5-diyl group, but in each compound, a transdecahydronaphthalene-trans-2,6-diyl group, one or more A naphthalene-2,6-diyl group optionally substituted by a nitrogen atom, a tetrahydronaphthalene-2,6-diyl group optionally substituted by one or two fluorine atoms, and a fluorine atom The number of 1,4-cyclohexenylene group, 1,3-dioxane-trans-2,5-diyl group, pyrimidine-2,5-diyl group or pyridine-2,5-diyl group may be within 1 The other ring is preferably a trans-1,4-cyclohexylene group or a 1,4-phenylene group optionally substituted by 1 to 2 fluorine atoms or a methyl group.

L ^g , L ^h and ^Li are each a linking group, and each independently represents a single bond, an ethylene group (—CH ₂ CH ₂ —), a 1,2-propylene group (—CH (CH ₃ ) CH ₂ — and ) —CH ₂ CH (CH ₃ ) —), 1,4-butylene group, —COO—, —OCO—, —OCF ₂ —, —CF ₂ O—, —CH═CH—, —CH═CF—, —CF═CH—, —CF═CF—, —C≡C— or —CH═NN═CH—, each represents a single bond, ethylene group, 1,4-butylene group, —COO—, —OCO—, —OCF ₂ —, —CF ₂ O—, —CF═CF—, —C≡C— or —CH═NN═CH— are preferred, and at least one of them in (C2) and that in (C3) It is preferable that at least two of them represent a single bond.

  The more preferable form in (C1) can be represented by the following general formulas (C1a) to (C1h).

In the above formulas, R ^f and R ^g are each independently a linear alkyl group having 1 to 7 carbon atoms, a linear 1-alkenyl group having 2 to 7 carbon atoms, or 4 to 7 carbon atoms. A linear 3-alkenyl group, a linear alkoxyl group having 1 to 3 carbon atoms, or a linear alkyl group having 1 to 5 carbon atoms substituted at the terminal by an alkoxyl group having 1 to 3 carbon atoms is represented. However, at least one represents a linear alkyl group having 1 to 7 carbon atoms, a linear 1-alkenyl group having 2 to 7 carbon atoms, or a linear 3-alkenyl group having 4 to 7 carbon atoms. However, if the ring G1~ ring G8 is an aromatic ring, the corresponding R ^f is except 1-alkenyl and alkoxy group, when the ring H1~ ring H8 is an aromatic ring, the corresponding R ^g is 1-alkenyl and alkoxy Excluding groups.

  Ring G1 and Ring H1 are each independently substituted with a trans-1,4-cyclohexylene group, a transdecahydronaphthalene-trans-2,6-diyl group, one or two fluorine atoms or a methyl group. 1,4-phenylene group, naphthalene-2,6-diyl group optionally substituted by one or more fluorine atoms, tetrahydronaphthalene-2 optionally substituted by 1 to 2 fluorine atoms, 6-diyl group, 1,4-cyclohexenylene group optionally substituted by 1 to 2 fluorine atoms, 1,3-dioxane-trans-2,5-diyl group, pyrimidine-2,5-diyl Group or a pyridine-2,5-diyl group, but in each compound, a transdecahydronaphthalene-trans-2,6-diyl group, one or more fluorine atoms A more optionally substituted naphthalene-2,6-diyl group, a tetrahydronaphthalene-2,6-diyl group optionally substituted by 1 to 2 fluorine atoms, and an optionally substituted 1 atom , 4-cyclohexenylene group, 1,3-dioxane-trans-2,5-diyl group, pyrimidine-2,5-diyl group or pyridine-2,5-diyl group is preferably within one, In this case, the other ring is a trans-1,4-cyclohexylene group or a 1,4-phenylene group optionally substituted by 1 to 2 fluorine atoms or a methyl group. Ring G2 and Ring H2 are each independently substituted with a trans-1,4-cyclohexylene group, transdecahydronaphthalene-trans-2,6-diyl group, 1 to 2 fluorine atoms or a methyl group. 1,4-phenylene group, naphthalene-2,6-diyl group optionally substituted by one or more fluorine atoms, tetrahydronaphthalene-2 optionally substituted by 1 to 2 fluorine atoms, Represents a 6-diyl group, but in each compound, a transdecahydronaphthalene-trans-2,6-diyl group, a naphthalene-2,6-diyl group optionally substituted by one or more fluorine atoms, The number of tetrahydronaphthalene-2,6-diyl groups which may be substituted by two fluorine atoms is preferably no more than one. The other ring is a trans-1,4-cyclohexylene group or a 1,4-phenylene group optionally substituted by 1 to 2 fluorine atoms or a methyl group. Ring G3 and Ring H3 are each independently a 1,4-phenylene group optionally substituted by 1 to 2 fluorine atoms or a methyl group, and naphthalene-2 optionally substituted by one or more fluorine atoms , 6-diyl group, tetrahydronaphthalene-2,6-diyl group optionally substituted by 1 or 2 fluorine atoms, naphthalene optionally substituted by one or more fluorine atoms in each compound It is preferable that the number of the -2,6-diyl group and the tetrahydronaphthalene-2,6-diyl group optionally substituted by 1 or 2 fluorine atoms is 1 or less.

  The more preferable form in (C2) can be represented by the following general formulas () C2a) to (C2m).

In the above formula, ring G1, ring G2, ring G3, ring H1, ring H2, and ring H3 have the same meanings as described above, ring I1 is the same as ring G1, ring I2 is the same as ring G2, and ring I3 is the same as ring G3. Represents meaning. In each of the above compounds, a transdecahydronaphthalene-trans-2,6-diyl group, a naphthalene-2,6-diyl group optionally substituted by one or more fluorine atoms, and one or two fluorine atoms A tetrahydronaphthalene-2,6-diyl group optionally substituted by 1, a 1,4-cyclohexenylene group optionally substituted by a fluorine atom, a 1,3-dioxane-trans-2,5-diyl group, The number of pyrimidine-2,5-diyl groups or pyridine-2,5-diyl groups is preferably 1 or less, and the other ring in that case is a trans-1,4-cyclohexylene group or 1 to 2 groups. A 1,4-phenylene group which may be substituted with a fluorine atom or a methyl group.
Next, the more preferable form in (C3) can be represented by the following general formulas (C3a) to (C3f).

  In the above formula, ring G1, ring G2, ring H1, ring H2, ring I1 and ring I2 have the same meanings as described above, and ring J1 has the same meaning as ring G1 or ring J2, respectively. In each of the above compounds, a transdecahydronaphthalene-trans-2,6-diyl group, a naphthalene-2,6-diyl group optionally substituted by one or more fluorine atoms, and one or two fluorine atoms A tetrahydronaphthalene-2,6-diyl group optionally substituted by 1, a 1,4-cyclohexenylene group optionally substituted by a fluorine atom, a 1,3-dioxane-trans-2,5-diyl group, The number of pyrimidine-2,5-diyl groups or pyridine-2,5-diyl groups is preferably 1 or less, and the other ring in that case is a trans-1,4-cyclohexylene group or 1 to 2 groups. A 1,4-phenylene group which may be substituted with a fluorine atom or a methyl group.

In the present invention, the compound of the general formula (1) can be produced as follows. Of course, the spirit and scope of the present invention are not limited by these production examples.
(Manufacturing method 1) General formula (7)

(Wherein R ¹ , A ¹ , A ² , Z ¹ and m each independently represent the same meaning as in the general formula (1), X is a chlorine atom, a bromine atom, an iodine atom, a benzenesulfonyloxy group, p A compound represented by -toluenesulfonyloxy group, methanesulfonyloxy group or trifluoromethanesulfonyloxy group) and trimethylsilylacetylene, tetrakistriphenylphosphine palladium (0), palladium (II) acetate or bis (trichloride In the presence of a palladium-based transition metal catalyst such as phenylphosphine) palladium (II), the Sonogashira reaction is carried out in the presence of a base and a copper salt, thereby obtaining

(Wherein R ¹ , A ¹ , A ² , Z ¹ and m each independently represent the same meaning as in general formula (1), and TMS represents a trimethylsilyl group) to obtain a compound represented by it can.

  Examples of the base include butylamine, diethylamine, triethylamine, diisopropylamine, piperidine, ammonia and the like, preferably triethylamine and diisopropylamine. Preferred examples of the copper salt include copper (I) iodide and copper (I) bromide. X can be exemplified by bromine, iodine and trifluoromethanesulfonyloxy groups, with iodine and trifluoromethanesulfonyloxy groups being particularly preferred.

  Any solvent can be used as long as it allows the reaction to proceed appropriately. Ether solvents, hydrocarbon solvents, aromatic solvents, polar solvents, and the like can be preferably used, and amines used as bases can also be used. Can also be used as a solvent. Ether solvents include 1,4-dioxane, 1,3-dioxane, tetrahydrofuran, diethyl ether, t-butyl methyl ether, etc., and hydrocarbon solvents include pentane, hexane, cyclohexane, heptane, octane, etc. Benzene, toluene, xylene, mesitylene, chlorobenzene, dichlorobenzene, etc. as group solvents, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, water, etc. as polar solvents Can be cited as a good example. Of these, polar solvents such as tetrahydrofuran, N, N-dimethylformamide and N, N-dimethylacetamide are preferred. Each of the above solvents may be used alone, or two or more solvents may be mixed and used.

  The reaction temperature can be in the range from the freezing point of the solvent to the reflux temperature, preferably 20 ° C to 60 ° C.

  Next, the compound represented by the general formula (6) is deprotected with acetylene using tetrabutylammonium fluoride or the like to obtain the general formula (9).

(Wherein, R ¹ , A ¹ , A ² , Z ¹ and m each independently represent the same meaning as in general formula (1)) can be obtained.

  Any solvent can be used as long as it allows the reaction to proceed appropriately, but ether solvents, hydrocarbon solvents, aromatic solvents, and the like can be preferably used. Ether solvents include 1,4-dioxane, 1,3-dioxane, tetrahydrofuran, diethyl ether, t-butyl methyl ether, etc., and hydrocarbon solvents include pentane, hexane, cyclohexane, heptane, octane, etc. Examples of the group solvent include benzene, toluene, xylene, mesitylene and the like. Of these, ether solvents such as 1,4-dioxane and tetrahydrofuran are preferred. Each of the above solvents may be used alone, or two or more solvents may be mixed and used.

  Although reaction temperature can be performed in the recirculation | reflux temperature range from the freezing point of a solvent, -40 degreeC to 10 degreeC is preferable.

  Next, general formula (10)

(Wherein R ² , A ⁵ , A ⁶ , Z ³ and p independently represent the same meaning as in general formula (1)) and sodium nitrite were reacted under acidic conditions. After, general formula (11)

(Wherein A ³ , A ⁴ , Z ² and n each independently represent the same meaning as in general formula (1)) and a diazo coupling reaction under basic conditions with a compound represented by the general formula (12)

(Wherein R ² , A ^{3 to} A ⁶ , Z ² , Z ³ n and p each independently represent the same meaning as in general formula (1)) can be obtained.
As the acid used for the acidic condition, an inorganic acid is preferably used, and hydrochloric acid, sulfuric acid and the like are particularly preferable. As a base used for making it basic, an inorganic base is preferably used, and sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium bicarbonate are particularly preferable.

  Any solvent can be used as long as it allows the reaction to proceed suitably, but ether solvents, hydrocarbon solvents, polar solvents, and the like can be preferably used. Ether solvents include 1,4-dioxane, 1,3-dioxane, tetrahydrofuran, diethyl ether, t-butyl methyl ether, etc., and hydrocarbon solvents include pentane, hexane, cyclohexane, heptane, octane, etc., polar Examples of the solvent include methanol, ethanol, propanol, water and the like. Among these, water-soluble ether solvents such as 1,4-dioxane and tetrahydrofuran and water are preferable. Each of the above solvents may be used alone, or two or more solvents may be mixed and used.

  Although reaction temperature can be performed in the recirculation | reflux temperature range from the freezing point of a solvent, -40 degreeC to 10 degreeC is preferable.

  Next, the compound represented by the general formula (12) is reacted with trifluoromethanesulfonic anhydride in the presence of a base, and the general formula (13)

(Wherein R ² , A ^{3 to} A ⁶ , Z ² , Z ³ , n and p each independently represent the same meaning as in general formula (1), and Tf represents a trifluoromethanesulfonyl group). Can be obtained.

  As the base, amines are preferably used, and triethylamine, diisopropylamine, and pyridine are particularly preferable.

  Any solvent may be used as long as it allows the reaction to proceed suitably. Ether solvents, hydrocarbon solvents, aromatic solvents, chlorine solvents, and the like can be preferably used. Ether solvents include 1,4-dioxane, 1,3-dioxane, tetrahydrofuran, diethyl ether, t-butyl methyl ether, etc., and hydrocarbon solvents include pentane, hexane, cyclohexane, heptane, octane, etc. Examples of the group solvent include benzene, toluene, xylene, mesitylene and the like, and examples of the chlorine solvent include dichloromethane, chloroform, 1,2-dichloroethane and the like. Of these, chlorinated solvents such as dichloromethane, chloroform, and 1,2-dichloroethane are preferable. Each of the above solvents may be used alone, or two or more solvents may be mixed and used.

  Although reaction temperature can be performed in the recirculation | reflux temperature range from the freezing point of a solvent, -40 degreeC to 10 degreeC is preferable.

  Next, the compound represented by the general formula (13) and the compound represented by the general formula (9) are converted into tetrakistriphenylphosphine palladium (0), palladium (II) acetate or bis (triphenylphosphine) palladium dichloride. A compound represented by the general formula (1) can be obtained by performing a coupling reaction in the presence of a base and a copper salt in the presence of a palladium-based transition metal catalyst such as (II).

  Examples of preferred bases include butylamine, diethylamine, triethylamine, diisopropylamine, piperidine, and ammonia. Among them, triethylamine and diisopropylamine are preferred. Preferred examples of the copper salt include copper (I) iodide and copper (I) bromide. Preferred examples of X include bromine, iodine and trifluoromethanesulfonyloxy groups, with iodine and trifluoromethanesulfonyloxy groups being more preferred.

  Any solvent can be used as long as it allows the reaction to proceed suitably. Ether solvents, hydrocarbon solvents, aromatic solvents, polar solvents, and the like can be preferably used, and the amine used as the base can be selected. It can also be used as a solvent. Ether solvents include 1,4-dioxane, 1,3-dioxane, tetrahydrofuran, diethyl ether, t-butyl methyl ether, etc., and hydrocarbon solvents include pentane, hexane, cyclohexane, heptane, octane, etc. Benzene, toluene, xylene, mesitylene, chlorobenzene, dichlorobenzene, etc. as group solvents, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, water, etc. as polar solvents Can be cited as a good example. Of these, polar solvents such as tetrahydrofuran, N, N-dimethylformamide and N, N-dimethylacetamide are preferred. Each of the above solvents may be used alone, or two or more solvents may be mixed and used.

The reaction temperature can be in the range from the freezing point of the solvent to the reflux temperature, but is preferably 20 ° C to 120 ° C.
(Manufacturing method 2) The compound represented by General formula (9) obtained by manufacturing method 1, and General formula (14)

(Wherein A ³ , A ⁴ , Z ² and n each independently represent the same meaning as in general formula (1), X is a chlorine atom, a bromine atom, an iodine atom, a benzenesulfonyloxy group, p-toluenesulfonyl) An oxy group, a methanesulfonyloxy group or a trifluoromethanesulfonyloxy group) and tetrakistriphenylphosphine palladium (0), palladium (II) acetate or bis (triphenylphosphine) palladium (II) chloride In the presence of a palladium-based transition metal catalyst such as a base and a copper salt in the presence of a Sonogashira reaction,

(Wherein R ¹ , A ^{1 to} A ⁴ , Z ¹ , Z ² , m and n each independently represent the same meaning as in general formula (1)) can be obtained.

  Examples of the base include butylamine, diethylamine, triethylamine, diisopropylamine, piperidine, and ammonia, preferably triethylamine, diisopropylamine, and ammonia. Preferred examples of the copper salt include copper (I) iodide and copper (I) bromide. Preferred examples of X include bromine, iodine and trifluoromethanesulfonyloxy groups, with iodine and trifluoromethanesulfonyloxy groups being more preferred.

  Any solvent can be used as long as it allows the reaction to proceed suitably. Ether solvents, hydrocarbon solvents, aromatic solvents, polar solvents, and the like can be preferably used, and the amine used as the base can be selected. It can also be used as a solvent. Ether solvents include 1,4-dioxane, 1,3-dioxane, tetrahydrofuran, diethyl ether, t-butyl methyl ether, etc., and hydrocarbon solvents include pentane, hexane, cyclohexane, heptane, octane, etc. Benzene, toluene, xylene, mesitylene, chlorobenzene, dichlorobenzene, etc. as group solvents, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, water, etc. as polar solvents Can be cited as a good example. Of these, polar solvents such as tetrahydrofuran, N, N-dimethylformamide, N, N-dimethylacetamide, and water are preferable. Each of the above solvents may be used alone, or two or more solvents may be mixed and used.

  The reaction temperature can be in the range from the freezing point of the solvent to the reflux temperature, but is preferably 20 ° C to 120 ° C.

  Next, after reacting the compound represented by the general formula (15) and sodium nitrite under acidic conditions, the general formula (16)

(Wherein A ⁵ , A ⁶ , Z ³ and p each independently represent the same meaning as in general formula (1)) and a diazo coupling reaction under basic conditions with a compound represented by the general formula (17)

(Wherein R ¹ , A ^{1 to} A ⁶ , Z ^{1 to} Z ³ , m, n, and p each independently represent the same meaning as in general formula (1)). it can.

  As the acid used for the acidic condition, an inorganic acid is preferably used, and hydrochloric acid, sulfuric acid and the like are particularly preferable. As the base used for basic conditions, an inorganic base is preferably used, and sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium hydrogen carbonate are particularly preferable.

  Any solvent can be used as long as it allows the reaction to proceed suitably, but ether solvents, hydrocarbon solvents, polar solvents, and the like can be preferably used. Ether solvents include 1,4-dioxane, 1,3-dioxane, tetrahydrofuran, diethyl ether, t-butyl methyl ether, etc., and hydrocarbon solvents include pentane, hexane, cyclohexane, heptane, octane, etc., polar Examples of the solvent include methanol, ethanol, propanol, water and the like. Among these, water-soluble ether solvents such as 1,4-dioxane and tetrahydrofuran and water are preferable. Each of the above solvents may be used alone, or two or more solvents may be mixed and used.

  Although reaction temperature can be performed in the recirculation | reflux temperature range from the freezing point of a solvent, -40 degreeC to 10 degreeC is preferable.

  Next, the compound represented by the general formula (17) and the general formula (18)

(In the formula, R ⁴ represents an alkyl group having 1 to 12 carbon atoms or an alkenyl group having 2 to 12 carbon atoms, and X represents a chlorine atom, bromine atom, iodine atom, benzenesulfonyloxy group, p-toluenesulfonyloxy group, A compound represented by a methanesulfonyloxy group or a trifluoromethanesulfonyloxy group) is reacted in the presence of a base to formula (19)

(In the formula, R ¹ , A ^{1 to} A ⁶ , Z ^{1 to} Z ³ , m, n and p each independently represent the same meaning as in the general formula (1), and R ⁴ is alkyl having 1 to 12 carbon atoms. Group or an alkenyl group having 2 to 12 carbon atoms can be obtained.

  As the base, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, potassium carbonate and the like can be preferably used.

  Any solvent can be used as long as it allows the reaction to proceed suitably, but ether solvents, hydrocarbon solvents, polar solvents, and the like can be preferably used. Ether solvents include 1,4-dioxane, 1,3-dioxane, tetrahydrofuran, diethyl ether, t-butyl methyl ether, etc., and hydrocarbon solvents include pentane, hexane, cyclohexane, heptane, octane, etc., polar Preferred examples of the solvent include N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, acetone, acetonitrile and the like. Of these, ether solvents such as 1,4-dioxane and tetrahydrofuran and polar solvents such as N, N-dimethylformamide, N, N-dimethylacetamide and acetone are preferable. Each of the above solvents may be used alone, or two or more solvents may be mixed and used.

  The reaction temperature can be in the range from the freezing point of the solvent to the reflux temperature, but is preferably 20 ° C to 130 ° C.

  EXAMPLES Hereinafter, although an Example is given and this invention is further explained in full detail, this invention is not limited to these Examples.

  The phase transition temperature was measured using a polarizing microscope equipped with a temperature control stage and a differential scanning calorimeter (DSC).

  “%” In the compositions of the following examples and comparative examples means “mass%”.

_TN-I represents an upper limit temperature indicating a nematic phase.

  The following abbreviations are used in compound descriptions.

THF: Tetrahydrofuran DMF: N, N-dimethylformamide TMS: Trimethylsilyl group Tf: Trifluoromethanesulfonyl group Et: Ethyl group, Pr: n-propyl group, Bu: n-butyl group, Pen: n-pentyl group (Example 1) ) Preparation of 4- (2,6-difluoro-4-propylphenylethynyl) -4'-ethylazobenzene

  180 g of 2,6-difluoro-4-propyliodobenzene (synthesized in the same manner as in Molecular Crystals and Liquid Crystals, 1995, 260, 93-106) under nitrogen atmosphere, 145 mL of triethylamine, 4.9 g of copper iodide, 14.8 g of tetrakistriphenylphosphine palladium was heated to 75 ° C. in 300 mL of DMF, 75 g of trimethylsilylacetylene was added dropwise, and the mixture was further stirred for 11 hours. After cooling, water and toluene were added and stirred, and then the organic phase was separated. The aqueous phase was extracted with toluene, the organic phases were combined, washed with 10% hydrochloric acid, saturated aqueous sodium hydrogen carbonate solution and saturated brine, dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. Purification by column chromatography gave 160 g of 2- (2,6-difluoro-4-propylphenyl) -trimethylsilylacetylene.

  Next, in a nitrogen atmosphere, a solution obtained by dissolving 159 g of 2- (2,6-difluoro-4-propylphenyl) -trimethylsilylacetylene in 500 mL of THF is ice-cooled, and 1 mol / L at a rate at which the reaction temperature becomes 10 ° C. or less. 660 mL of tetrabutylammonium fluoride in THF was added dropwise and stirred at room temperature for 1 hour. Water was added and stirred to separate the organic phase. The aqueous phase was extracted with hexane, the organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent was distilled off under reduced pressure. Purification by column chromatography gave 112 g of 2,6-difluoro-4-propylphenylacetylene.

  100 g of 4-ethylaniline and 206 mL of concentrated hydrochloric acid were dissolved in 200 mL of THF, ice-cooled, and a solution in which 57 g of sodium nitrite was dissolved in 250 mL of water was added dropwise at a rate such that the reaction solution temperature did not exceed 10 ° C., and the mixture was stirred for 1 hour. . A solution prepared by dissolving 82 g of phenol, 101 g of sodium carbonate, and 35 g of sodium hydroxide in 300 mL of water was ice-cooled, and the solution prepared earlier was added dropwise at a rate such that the reaction solution temperature did not exceed 10 ° C., and stirred for 3 hours under ice-cooling. . Concentrated hydrochloric acid was added thereto until it showed acidity, and then toluene was added and stirred to separate the organic phase. The aqueous phase was extracted with toluene, the organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent was distilled off. Purification by column chromatography and recrystallization gave 185 g of 4-ethyl-4'-hydroxyazobenzene.

  Next, 69 g of 4-ethyl-4′-hydroxyazobenzene and 36 g of pyridine were dissolved in 300 mL of dichloromethane, and 190 mL of a dichloromethane solution of 94 g of trifluoromethanesulfonic anhydride was added dropwise at a rate such that the reaction solution temperature did not exceed 10 ° C. The mixture was stirred for 1 hour while maintaining the temperature below ℃. After adding 10% hydrochloric acid to the reaction mixture and stirring, the organic phase was separated, washed with saturated aqueous sodium hydrogen carbonate solution and saturated brine, dried over anhydrous sodium sulfate, and the solvent was distilled off. Purification by column chromatography gave 106 g of 4-trifluoromethanesulfonyloxy-4'-ethylazobenzene.

Next, 82 g of 4-trifluoromethanesulfonyloxy-4′-ethylazobenzene, 1.8 g of copper (I) iodide, 5.4 g of tetrakistriphenylphosphine palladium, and 50 mL of triethylamine were heated to 75 ° C. in 110 mL of DMF, A solution prepared by dissolving 40 g of 6-difluoro-4-propylphenylacetylene in 40 mL of DMF was added dropwise, and the mixture was further stirred for 5 hours. After cooling, toluene and 10% hydrochloric acid were added to the reaction mixture and stirred, and the organic phase was separated. The aqueous phase was extracted with toluene, and the organic phases were combined, washed with a saturated aqueous sodium hydrogen carbonate solution and saturated brine, dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. Purification by column chromatography and recrystallization (acetone, methanol) gave 33 g of 4- (2,6-difluoro-4-propylphenylethynyl) -4′-ethylazobenzene.
¹ H-NMR (400 MHz, CDCl ₃ ): 0.95 (t, J = 7.2 Hz, 3H), 1.29 (t, J = 7.6 Hz, 3H), 1.65 (quintet, J = 7.6 Hz, 2H), 2.60 (t, J = 7.2 Hz, 2H), 2.74 (q, J = 7.6 Hz, 2H), 6.78 (d, J = 8.0 Hz, 2H) ), 7.35 (d, J = 8.4 Hz, 2H), 7.70 (d, J = 8.8 Hz, 2H), 7.86-7.91 (m, 4H).
MS m / z: 388 [M ⁺ ]
Phase transition temperature (° C.): Cr 106 N 212 Iso
Example 2 Preparation of 4- (2,6-difluoro-4-ethylphenylethynyl) -4′-ethylazobenzene 2,6-difluoro-4 instead of 2,6-difluoro-4-propyliodobenzene 4- (2,6-Difluoro-4-ethylphenylethynyl) -4′-ethylazobenzene was obtained in the same manner as in Example 1 except that -ethyliodobenzene was used.
¹ H-NMR (400 MHz, CDCl ₃ ): 1.25 (t, J = 7.6 Hz, 3H), 1.29 (t, J = 7.6 Hz, 3H), 2.65 (q, J = 7.6 Hz, 2H), 2.74 (q, J = 7.6 Hz, 2H), 6.80 (d, J = 8.0 Hz, 2H), 7.35 (d, J = 8.4 Hz, 2H) ), 7.70 (d, J = 8.4 Hz, 2H), 7.86-7.91 (m, 4H).
MS m / z: 374 [M ⁺ ]
Phase transition temperature (° C.): Cr 120 N 200 Iso
Example 3 Production of 4- (2,6-difluoro-4-propylphenylethynyl) -3 ′, 4′-difluoroazobenzene

4- (2,6-difluoro-4-propylphenylethynyl) -3 ′, 4′-difluoroazobenzene in the same manner as in Example 1 except that 3,4-difluoroaniline is used instead of 4-ethylaniline. Got.
¹ H-NMR (400 MHz, CDCl ₃ ): 0.96 (t, J = 7.6 Hz, 3H), 1.66 (quintet, J = 7.6 Hz, 2H), 2.60 (t, J = 7.6 Hz, 2H), 6.78 (d, J = 8.0 Hz, 2H), 7.33 (q, J = 8.6 Hz, 1H), 7.70-7.80 (m, 4H), 7.91 (d, J = 8.8 Hz, 2H).
Phase transition temperature (° C.): Cr 124 N 174 Iso
Example 4 Preparation of 4- (2,6-difluoro-4-propylphenylethynyl) -3 ′, 4 ′, 5′-trifluoroazobenzene 3,4,5-trimethyl instead of 4-ethylaniline 4- (2,6-difluoro-4-propylphenylethynyl) -3 ′, 4 ′, 5′-trifluoroazobenzene was obtained in the same manner as in Example 1 except that fluoroaniline was used.
¹ H-NMR (400 MHz, CDCl ₃ ): 0.96 (t, J = 7.2 Hz, 3H), 1.66 (quintet, J = 7.6 Hz, 2H), 2.60 (t, J = 7.6 Hz, 2H), 6.79 (d, J = 8.4 Hz, 2H), 7.60-7.67 (m, 2H), 7.72 (d, J = 8.8 Hz, 2H), 7.91 (d, J = 8.4 Hz, 2H).
Phase transition temperature (° C.): Cr 138 N 147 Iso
Example 5 Production of 4- (2,6-difluoro-4-pentylphenylethynyl) -4′-propyloxyazobenzene

  To a suspension of 44 g of 4-iodoaniline, 0.8 g of copper (I) iodide, 1.4 g of bistriphenylphosphine palladium dichloride (II) and 420 mL of 1M aqueous ammonia in 500 mL of THF, 2,6-difluoro-4- 46 g of pentylphenylacetylene (obtained in the same manner as in Example 1 except that 2,6-difluoro-4-pentyliodobenzene was used instead of 2,6-difluoro-4-propyliodobenzene) was dissolved in 70 mL of THF. The solution was added dropwise at room temperature and further stirred for 9 hours. Subsequently, saturated brine was added and stirred to separate the organic phase. After extraction from the aqueous phase with THF, the organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent was distilled off under reduced pressure. The obtained solid was purified by column chromatography. Subsequently, after dissolving in THF, adding 40 mL of 6M hydrochloric acid and stirring, the organic phase was separated. After extraction from the aqueous phase with THF, the organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent was distilled off. The obtained solid was purified by recrystallization (toluene, ethanol) to obtain 45 g of 4- (2,6-difluoro-4-pentylphenylethynyl) aniline hydrochloride.

  Next, a solution prepared by dissolving 45 g of 4- (2,6-difluoro-4-pentylphenylethynyl) aniline hydrochloride and 12 mL of concentrated hydrochloric acid in 550 mL of THF was ice-cooled, and the reaction solution temperature did not exceed 10 ° C. An aqueous solution in which 9 g of sodium nitrite was dissolved in 60 mL of water was dropped, and the mixture was stirred at 10 ° C. or lower for 30 minutes to prepare a diazonium salt. The previously prepared solution was added dropwise to an aqueous solution prepared by dissolving 14 g of ice-cooled phenol, 15 g of sodium carbonate, and 6 g of sodium hydroxide in 200 mL of water at a rate such that the reaction solution temperature did not exceed 10 ° C. Stir for hours. Subsequently, 150 mL of 10% hydrochloric acid and THF were added and stirred to separate the organic phase. After extraction from the aqueous phase with THF, the organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent was distilled off. Purification by column chromatography and recrystallization (methanol) gave 15 g of 4- (2,6-difluoro-4-pentylphenylethynyl) -4'-hydroxyazobenzene.

Next, a solution obtained by suspending 15 g of 4- (2,6-difluoro-4-pentylphenylethynyl) -4′-hydroxyazobenzene, 8 g of potassium carbonate, and 10 g of 1-iodopropane in 65 mL of acetone, 65 mL of THF, and 10 mL of DMF, The mixture was stirred at 60 ° C. for 13 hours. After removing the solid content by suction filtration, the solvent was distilled off under reduced pressure. The obtained solid content was dissolved in toluene, washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent was distilled off. . Purification by column chromatography and recrystallization (acetone) gave 9 g of 4- (2,6-difluoro-4-pentylphenylethynyl) -4′-propyloxyazobenzene.
¹ H-NMR (400 MHz, CDCl ₃ ): 0.90 (t, J = 6.8 Hz, 3H), 1.07 (t, J = 7.2 Hz, 3H), 1.29-1.37 ( m, 4H), 1.62 (q, J = 7.6 Hz, 2H), 1.86 (quintet, J = 6.8 Hz, 2H), 2.61 (t, J = 7.6 Hz, 2H), 4.02 (t, J = 6.8 Hz, 2H), 6.78 (d, J = 8.0 Hz, 2H), 7.01 (d, J = 9.2 Hz, 2H), 7.67 (d , J = 8.4 Hz, 2H), 7.87 (d, J = 7.8 Hz, 2H), 7.92 (d, J = 8.8 Hz, 2H).
MS m / z: 446 [M ⁺ ]
Phase transition temperature (° C.): Cr 100 N 230 Iso
Example 6 Production of 4- (2,6-difluoro-4-pentylphenylethynyl) -4 ′-(1-pentynyl) azobenzene

  10 g of 4- (2,6-difluoro-4-pentylphenylethynyl) -4′-hydroxyazobenzene (synthesized in the same manner as in Example 5) and 3 g of pyridine were dissolved in 25 mL of dichloromethane to obtain trifluoromethanesulfonic acid. 15 mL of a solution of 7.7 g of anhydride in dichloromethane was added dropwise at a rate such that the temperature of the reaction solution did not exceed 10 ° C., and the mixture was stirred for 1 hour while maintaining a temperature of 10 ° C. or lower. After adding 10% hydrochloric acid to the reaction mixture and stirring, the organic phase was separated, washed with saturated aqueous sodium hydrogen carbonate solution and saturated brine, dried over anhydrous sodium sulfate, and the solvent was distilled off. Purification by column chromatography gave 13 g of 4- (2,6-difluoro-4-pentylphenylethynyl) -4 'trifluoromethanesulfonyloxyazobenzene.

  Next, 13 g of 4- (2,6-difluoro-4-pentylphenylethynyl) -4′trifluoromethanesulfonyloxyazobenzene, 0.18 g of copper (I) iodide, 0.56 g of tetrakistriphenylphosphine palladium, and 8 mL of triethylamine were added. The mixture was heated to 40 ° C. in 17 mL of DMF, and a solution prepared by dissolving 2.5 g of 1-pentine in 4 mL of DMF was added dropwise, and the mixture was further stirred for 5 hours. After cooling, toluene and 10% hydrochloric acid were added to the reaction mixture and stirred, and the organic phase was separated. The aqueous phase was extracted with toluene, and the organic phases were combined, washed with a saturated aqueous sodium hydrogen carbonate solution and saturated brine, dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure. Purification by column chromatography and recrystallization (acetone, methanol) gave 4.4 g of 4- (2,6-difluoro-4-pentylphenylethynyl) -4 '-(1-pentynyl) azobenzene.

MS m / z: 454 [M ⁺ ]
Comparative Example 1 Production of 4- (4-pentylphenylethynyl) -4′-propyloxyazobenzene Example 5 except that 4-pentylacetylene was used instead of 2,6-difluoro-4-pentylphenylacetylene In the same manner, 4- (4-pentylphenylethynyl) -4′-propyloxyazobenzene was obtained.

¹ H-NMR (400 MHz, CDCl ₃ ): 0.90 (t, J = 6.4 Hz, 3H), 1.07 (t, J = 7.6 Hz, 3H), 1.32-1.37 ( m, 4H), 1.63 (q, J = 6.8 Hz, 2H), 1.85 (quintet, J = 7.2 Hz, 2H), 2.62 (t, J = 7.2 Hz, 2H), 4.01 (t, J = 6.8 Hz, 2H), 7.01 (d, J = 8.8 Hz, 2H), 7.18 (d, J = 8.0 Hz, 2H), 7.47 (d , J = 8.0 Hz, 2H), 7.64 (d, J = 8.0 Hz, 2H), 7.85-7.97 (m, 4H).
MS m / z: 410 [M ⁺ ]
Phase transition temperature (° C.): Cr 133 N 206 Iso
Example 7 Preparation of Liquid Crystal Composition-1
Host liquid crystal composition (H) having the following composition

Was prepared. Here, the physical property values of (H) are as follows.

Nematic phase upper limit temperature (T _N-I ): 77.9 ° C.
Refractive index anisotropy (Δn): 0.1024
A liquid crystal composition (MA) comprising 90% of the base liquid crystal (H) and 10% of 4- (2,6-difluoro-4-propylphenylethynyl) -4′-ethylazobenzene obtained in Example 1 Was prepared. The physical properties of this composition are as follows.

T _N-I : 87.5 ° C
Δn: 0.1430
The liquid crystal composition (MA) containing 4- (2,6-difluoro-4-propylphenylethynyl) -4′-ethylazobenzene has a value of Δn which is 40% larger than that of the base liquid crystal (H). Indicated. This indicates that 4- (2,6-difluoro-4-propylphenylethynyl) -4′-ethylazobenzene has a very large Δn value.

Further, the liquid crystal composition (MA) contains 10% of 4- (2,6-difluoro-4-propylphenylethynyl) -4′-ethylazobenzene. It was not seen and showed a stable liquid crystal phase. From this, it was also found that the present compound exhibits excellent compatibility with other liquid crystal compositions. Further, TN _-I of the liquid crystal composition (MA) is 9.6 ° C. higher than that of the base liquid crystal, and 4- (2,6-difluoro-4-propylphenylethynyl) -4′-ethylazobenzene is high. It can be seen that the liquid crystal composition to which is added has good nematic liquid crystal properties.

In addition, it was found that a cholesteric liquid crystal display device prepared using this liquid crystal composition (MA) exhibits excellent display characteristics.
(Example 8) Preparation of liquid crystal composition-2
A liquid crystal composition (MB) comprising 90% of the base liquid crystal (H) and 10% of 4- (2,6-difluoro-4-ethylphenylethynyl) -4′-ethylazobenzene obtained in Example 2 Prepared. The physical properties of this composition are as follows.

T _N-I : 86.7 ° C
Δn: 0.1432
The liquid crystal composition (MB) containing 4- (2,6-difluoro-4-ethylphenylethynyl) -4′-ethylazobenzene showed a Δn which was 40% larger than that of the base liquid crystal (H). . This indicates that 4- (2,6-difluoro-4-ethylphenylethynyl) -4′-ethylazobenzene has a very large Δn value.

The liquid crystal composition (MB) contains 10% of 4- (2,6-difluoro-4-ethylphenylethynyl) -4′-ethylazobenzene, but does not cause precipitation and is a stable liquid crystal. From showing the phase, it was also found that the compound of the present application showed excellent liquid crystallinity and compatibility with other liquid crystal compositions. Further, TN _-I of the liquid crystal composition (MB) is 8.8 ° C. higher than that of the base liquid crystal, and 4- (2,6-difluoro-4-propylphenylethynyl) -4′-ethylazobenzene is high. It can be seen that has a good nematic liquid crystallinity.

Further, it was found that a cholesteric liquid crystal display element prepared using this liquid crystal composition (MB) exhibits excellent display characteristics.
Example 9 Preparation of Liquid Crystal Composition-3
A liquid crystal composition (MC) comprising 90% of the base liquid crystal (H) and 10% of 4- (2,6-difluoro-4-pentylphenylethynyl) -4′-propyloxyazobenzene obtained in Example 3 Was prepared. The physical properties of this composition are as follows.

T _N-I : 89.8 ° C
Δn: 0.1440
The liquid crystal composition (MC) containing 4- (2,6-difluoro-4-pentylphenylethynyl) -4′-propyloxyazobenzene has a value of Δn that is 41% larger than that of the base liquid crystal (H). showed that. This indicates that 4- (2,6-difluoro-4-pentylphenylethynyl) -4′-propyloxyazobenzene has a very large Δn value.

The liquid crystal composition (MC) contains 10% of 4- (2,6-difluoro-4-pentylphenylethynyl) -4′-propyloxyazobenzene, but is stable without causing precipitation. Since it showed a liquid crystal phase, it was also found that the compound of the present application showed excellent liquid crystallinity and compatibility with other liquid crystal compositions. Further, TN _-I of the liquid crystal composition (MC) is 11.9 ° C. higher than that of the base liquid crystal, and 4- (2,6-difluoro-4-pentylphenylethynyl) -4′-propyloxy is higher. It can be seen that azobenzene has good nematic liquid crystal properties.

Further, it was found that a cholesteric liquid crystal display element prepared using this liquid crystal composition (MC) exhibits excellent display characteristics.
Comparative Example 2 Preparation of Liquid Crystal Composition-4
A liquid crystal composition (MD) comprising 90% of the base liquid crystal (H) and 10% of 4- (4-pentylphenylethynyl) -4′-propyloxyazobenzene obtained in Comparative Example 1 was prepared. The physical properties of this composition are as follows.

T _N-I : 88.1 ° C
Δn: 0.1427
The liquid crystal composition (MD) containing (4- (4-pentylphenylethynyl) phenyl) -azo- (4′-propyloxybenzene) has a value of Δn that is 39% larger than that of the base liquid crystal (H). showed that. This indicates that 4- (4-pentylphenylethynyl) -4′-propyloxyazobenzene has a large Δn value.

  However, when the liquid crystal composition (MD) was allowed to stand at room temperature for 1 week, it was observed that crystals were precipitated in the liquid crystal composition. This indicates that 4- (4-pentylphenylethynyl) -4'-propyloxyazobenzene has low compatibility with other liquid crystal compounds.

  As described above, it was found that the compound of the present invention represented by the general formula (1) exhibits an extremely large Δn. Further, it can be seen that the compatibility with other liquid crystal compositions is higher than that of 4- (4-pentylphenylethynyl) -4'-propyloxyazobenzene synthesized in Comparative Example 1. The known compounds represented by the formulas (E) and (F) show a smectic phase, whereas the compound of the present invention represented by the general formula (1) shows only a nematic phase and does not have a smectic phase. It became clear. From this, it is considered that the compound of the present invention exhibits a nematic phase in a wide temperature range.

Claims (9)

General formula (1)

Wherein R ¹ and R ² are each independently a fluorine atom, a chlorine atom, a cyano group, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. Or an alkenyloxy group having 2 to 12 carbon atoms, wherein each one or more hydrogen atoms may be independently substituted with fluorine atoms, and each —CH ₂ — group independently contains an oxygen atom. as two do not continuously bound more -O -, - CO -, - COO- or -OCO- may be substituted by, or ^{R 1} and ^{R 2} are each independently ^R 3 -Z ⁴ -(In the formula, R ³ represents an alkyl group having 1 to 12 carbon atoms or an alkenyl group having 2 to 12 carbon atoms, and one or more hydrogen atoms in the group may be independently substituted with fluorine atoms. , ^{Z 4} represents -CH = CH- or -C≡C- Represents a) not represent a substituent R ¹ and R ² are both fluorine atoms, selected from a chlorine atom and a cyano group,
Z ¹ , Z ² and Z ³ are each independently a single bond, —OCH ₂ —, —CH ₂ O—, —C ₂ H ₄ —, —C ₄ H ₈ —, —COO—, —OCO—, — CH═CH—, —CF═CF—, —CF ₂ O—, —OCF ₂ —, —CF ₂ CF ₂ — or —C≡C—
A ¹ , A ³ , A ⁴ , A ⁵ and A ⁶ each independently represents a 1,4-phenylene group, a naphthalene-1,4-diyl group or a naphthalene-2,6-diyl group, and A ¹ , A ⁵ and A ⁶ may be each independently substituted with a halogen atom, and one or more non-adjacent —CH═ in A ¹ , A ³ , A ⁴ , A ⁵ and A ⁶ is — May be replaced by N =
A ² represents a 2,6-difluoro-1,4-phenylene group,
m, n, and p each independently represent 0 or 1, but m + n + p represents 0 or 1. ) A compound represented by In the general formula (1), A ¹ , A ⁵ and A ⁶ are each independently a 1,4-phenylene group which may be unsubstituted or substituted by one or more fluorine atoms , and A ³ and A ^4. The compound according to claim 1, wherein ⁴ is an unsubstituted 1,4-phenylene group . The compound according to claim 1 or 2, wherein in the general formula (1), m, n and p are 0. In General Formula (1), at least one of R ¹ and R ² is an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkoxyl group having 1 to 12 carbon atoms, or an alkenyl having 2 to 12 carbon atoms. The compound according to claim 1, which is an oxy group or R ³ —Z ⁴ —. In the general formula (1), R ¹ and R ² are each independently an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkoxyl group having 1 to 12 carbon atoms, or an alkyl group having 2 to 12 carbon atoms. alkenyloxy group, or ^R 3 -Z ⁴ -, compound according to any one of claims 1-4. In the general formula (1), compound according to any one of claims 1 to 4 either one of R ¹ or R ² is a fluorine atom or a cyano group. A liquid crystal composition comprising at least one compound represented by the general formula (1) according to any one of claims 1 to 6. A liquid crystal display device using the liquid crystal composition according to claim 7. A cholesteric liquid crystal display device using the liquid crystal composition according to claim 7.