JPH0585971A - Compound having 1,1-difluoroethane link and liquid crystal composition containing the compound - Google Patents

Abstract

PURPOSE:To provide the title compound useful as a material for liquid crystal display elements. CONSTITUTION:The objective compound of formula I (R<1> and R<2> are each 1-16C alkyl or alkoxyl; ring A 1,4-phenylene or trans-1,4-cyclohexylene; m is 0 or 1; n is 1 or 2), e.g. 1,1-difluoro-2-(4-octyloxyphenyl)-1-[4-(4-octyloxyphenyl) phenyl] ethane. The present compound can be obtained by reaction of a dithiane derivative of formula II with a benzyl halide derivative of formula III in the presence of a strong base into a compound of formula IV, which is then reacted with a fluorinating agent such as tetrabutylammonium dihydrotrifluoride in the presence of an oxidizing agent (e.g. N-iodosuccinimide). The present compound can effectively reduce the birefringence anisotropy of nematic liquid crystal compositions; therefore, expanding the working temperature range without impairing the responsiveness of ferroelectric liquid crystals.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a compound having a 1,1-difluoroethane bond which is useful as an electro-optical liquid crystal display material.

[0002]

2. Description of the Related Art Liquid crystal display devices have come to be used in watches, calculators, various measuring instruments, automobile panels, word processors, electronic notebooks, printers, computers, televisions and the like. Typical liquid crystal display methods are TN (twisted nematic) type, STN (super twisted nematic) type, DS (dynamic light scattering) type, GH (guest host) type, and FLC (ferroelectric liquid crystal). ) And the like are known, of which the TN type and the STN type are most widely used at present.

A large number of compounds have been synthesized and known as liquid crystal materials used in these display systems. However, a compound that alone satisfies various required properties according to these display systems and applications is not known, and a large number of compounds are mixed according to the required properties and used as a liquid crystal composition. It is the actual situation.
Therefore, development of a liquid crystal compound having a certain excellent property is also very important.

A liquid crystal compound usually has, as its basic skeleton,
Two or three or more ring structures (1,4-phenylene group or its substitution product, 1,4-cyclohexylene group, pyridine-2,5-diyl group, pyrimidine-2,5-diyl group, 1, 3-dioxane-2,5-diyl group, etc.) has a structure in which it is bound directly or via a linking group.
The linking group, ester bond (-COO-), oxymethylene bond (-OCH ₂ -), an acetylene bond (-C≡C
-), ethane bond (-CH ₂ CH ₂ -) and the like are often used. Of these, compounds having an ethane bond have low viscosity, and other compounds exhibiting excellent properties can be obtained.
Especially well used.

[0005] Recently, as a linking group containing _{fluorine, -OCF 2 -, - SCF 2} -, or -COCF ₂
A compound having-(JP-A-2-289529),
Alternatively, a compound having -CF = CF- (Japanese Patent Laid-Open No. 3-4
No. 1037 gazette) has been reported, and it has become known to exhibit interesting characteristics. However, the compound having a linking group in which fluorine is introduced into the ethane bond has not been known so far because it is difficult to synthesize the compound, although its physical properties are interesting.

[0006]

Among various characteristics required of liquid crystal materials, birefringence anisotropy (Δn) is a very important characteristic. With the increase in display capacity,
Multiplex drive is becoming necessary, which requires a wide visual range. for that reason,
There is a need for compounds with small Δn.

Further, a major drawback of the current liquid crystal display element is that
The response is very slow. As a display method that improves this defect and enables high-speed response in the microsecond range,
A method using the above-mentioned ferroelectric liquid crystal has been reported and is being developed. Ferroelectric liquid crystals are usually composed of achiral compounds and are prepared by adding an optically active compound as a dopant to a host liquid crystal exhibiting an SC phase.
Further, in order to extend the temperature range to a high temperature range, a tricyclic compound can be used as a constituent material of the host liquid crystal, but a compound capable of extending the temperature range without deteriorating its responsiveness. Was little known. The problem to be solved by the present invention is that Δn is small,
It is an object of the present invention to provide a compound having a low viscosity and capable of expanding the temperature range of a liquid crystal composition when added to a host liquid crystal.

[0008]

In order to solve the above-mentioned problems, the present invention has the general formula (I)

[0009]

[Chemical 2]

(In the formula, R ¹ and R ² each independently represent an alkyl group or an alkoxyl group having 1 to 16 carbon atoms, and a linear group is particularly preferable. Particularly for nematic liquid crystal, carbon is preferable. An alkyl group or an alkoxyl group having 1 to 8 atoms is preferable, and an alkyl group or an alkoxyl group having 6 to 16 carbon atoms is preferable for a ferroelectric liquid crystal. Ring A is 1,4-phenylene group or trans-1,
Represents a 4-cyclohexylene group. m represents 0 or 1, n represents 1 or 2, and it is particularly preferable that m + n is 1 or 2. ) Is provided.

The compound represented by the general formula (I) of the present invention can be produced, for example, according to the following production method. That is, the general formula (II)

[0012]

[Chemical 3]

(Wherein R ¹ , the rings A and m are represented by the general formula (I)
Has the same meaning as in. ) In the presence of a strong base, a dithiane derivative represented by the general formula (III)

[0014]

[Chemical 4]

(Wherein R ² and n have the same meanings as in the general formula (I), and X represents a chlorine, bromine or iodine atom), and a benzyl halide derivative represented by the general formula (I) Formula (IV)

[0016]

[Chemical 5]

An intermediate represented by the formula: wherein R ¹ , R ² , rings A, m and n have the same meaning as in formula (I) is prepared. By reacting this with a fluorinating agent such as tetrabutylammonium dihydrotrifluoride in the presence of an oxidizing agent such as N-iodosuccinimide (NIS) or N-bromosuccinimide (NBS), the general formula ( A compound of formula I) can be obtained.

Typical examples of the compounds represented by the general formula (I) thus produced are shown in Table 1.

[0019]

[Table 1]

(In Table 1, Cr represents a crystalline phase, SB represents a smectic B phase, and I represents an isotropic liquid phase.)

The compound represented by the general formula (I) of the present invention does not exhibit a nematic phase, but, for example, in the state of composition with another nematic liquid crystal compound having a positive or negative dielectric anisotropy, It can be used as a material of a field effect display cell such as a TN type or an STN type for the purpose of reducing Δn of the composition. In this case, R ¹ and R ² in the general formula (I) are preferably an alkyl group having 8 or less carbon atoms.

As described above, preferred examples of the nematic liquid crystal compound which can be used by mixing with the compound represented by the general formula (I) are, for example, 4-substituted benzoic acid 4-substituted phenyl ester and 4-substituted benzoic acid 4-substituted phenyl ester. Substituted cyclohexanecarboxylic acid 4-substituted phenyl ester, 4-substituted cyclohexanecarboxylic acid 4′-substituted biphenyl ester,
4- (4-Substituted cyclohexanecarbonyloxy) benzoic acid 4-substituted phenyl ester, 4- (4-substituted cyclohexyl) benzoic acid 4-substituted phenyl ester, 4-
(4-Substituted cyclohexyl) benzoic acid 4-substituted cyclohexyl ester, 4,4′-substituted biphenyl, 1- (4
-Substituted phenyl) -4-substituted cyclohexane, 4,4 "
-Substituted terphenyl, 1- (4'-substituted biphenylyl)
-4-Substituted cyclohexane, 2- (4-substituted phenyl)
-5-substituted pyrimidine etc. can be mentioned.

As shown in Example 5 described later, it is currently widely used as a nematic liquid crystal material having excellent viscosity.

[0024]

[Chemical 6]

The Δn at 20 ° C. of the host liquid crystal (A) consisting of (in the above formula, the cyclohexane ring represents the trans configuration) was 0.117. On the other hand, a mixed liquid crystal (M) comprising 90% by weight of the host liquid crystal (A) and 10% by weight of the compound of No. 3 represented by the general formula (I) shown in Table 1 was similarly measured for Δn. Was very small at 0.077. From this result, it is clear that the compound represented by the general formula (I) effectively reduces the Δn of the base liquid crystal by adding a small amount to the base liquid crystal (A).

Further, the compound represented by the general formula (I) of the present invention can also be used as a constituent component of the matrix liquid crystal in the ferroelectric liquid crystal. In this case, in the general formula (I), R
It is preferable that ¹ and R ² are alkyl groups having 6 or more carbon atoms. As shown in Example 6 below,

[0027]

[Chemical 7]

And 84% by weight of a base liquid crystal (B), which is composed of an SC (smectic C) phase and is composed of

[0029]

[Chemical 8]

A ferroelectric liquid crystal composition (F-1) containing 16% by weight of a chiral dopant (P) is 66.5%.
It showed an SC ^* (chiral smectic C) phase showing ferroelectricity at a temperature of not higher than 0 ° C., and its electro-optical response speed at 25 ° C. was 46 μsec.

On the other hand, 90% by weight of the base liquid crystal (B) and 10% by weight of the compound No. 1 in Table 1 of the present invention.
A matrix liquid crystal (C) consisting of
A ferroelectric liquid crystal composition (F-2) consisting of 84% by weight and 16% by weight of the chiral dopant (P) was obtained. Although the upper limit temperature of the SC ^* phase of this (F-2) increased by 68.5 ° C. and 2 ° C., the electro-optical response speed at 25 ° C. was 47 μsec, which was almost unchanged. From the above, it can be understood that the compound represented by the general formula (I) can extend the driving temperature range to a high temperature range without slowing the response speed of the liquid crystal composition.

[0032]

EXAMPLES The present invention will be further described below by showing Examples of the present invention. However, the present invention is not limited to these examples.

The phase transition temperature was measured by using a polarizing microscope equipped with a temperature control stage and a differential scanning calorimeter (DSC). The structures of the compounds are NMR, IR, M
Confirmed by S and elemental analysis. (Nea in IR
t) represents the measurement by the liquid film, and (KBr) represents the measurement by the tablet molding. CDCl _{3 in} NMR represents a solvent, s is a singlet, d is a doublet, t is a triplet, and quint.
et represents a quintet, sext represents a 6t, m represents a multiplet, and, for example, dt represents a doublet triplet, and b.
road represents broad absorption. M ^{+ in} MS represents a parent peak, and the numerical value in parentheses represents the relative intensity of the peak, while trace represents that the relative intensity is 1 or less. All "%" in the composition represent "% by weight".

Example 1 1,1-difluoro-2-
(4-octyloxyphenyl) -1- [4- (4-octyloxyphenyl) phenyl] ethane (in Table 1,
No. 1 compound) synthesis

(1-a) Synthesis of 2- [4- (4-octyloxyphenyl) phenyl] -1,3-dithiane

[0036]

[Chemical 9]

2.3 g (10 mmol) of 4- (4-octyloxyphenyl) benzaldehyde, 1 g (10 mmol) of propanedithiol and 20 ml of a solution of trimethylsilyl polyphosphoric acid (PPSE) in dichloromethane.
(Journal of Synthetic Organic Chemistry, 43, 1164 (1985))
Was stirred at room temperature for 30 minutes. After completion of the reaction, 50 ml of saturated aqueous sodium hydrogen carbonate solution was added, and the reaction product was mixed with 100 ml of ether, 100 ml of ethyl acetate and 100 ml of dichloromethane.
Extracted sequentially with ml. After the extract was concentrated, the obtained residue was recrystallized from a hexane / ether (5/1) mixed solvent to give 2- [4- (4-octyloxyphenyl) phenyl] -1,3-dithiane 2. 7 g (yield 91%) was obtained.

Colorless plate-like crystal Melting point 141 ° C. IR (KBr) 2940,2870,1610,15
00, 1470, 1290, 1280, 1250, 12
05,1180,830,815,770cm ^{-1 1} H N
MR (CDCl ₃ ) δ 0.89 (t, J = 7.0H
z, 3H), 1.2-1.4 (m, 8H), 1.4-1.5
(M, 2H), 1.80 (quintet, J = 6.6H
z, 2H), 1.9 to 2.0 (m, 1H), 2.18 (m
d, J = 14 Hz, 1H), 2.93 (dt, J = 13.
5 and 3.3 Hz, 2 H), 3.08 (td, J = 1
3.5 and 2.4 Hz, 2H), 3.99 (t, J = 6.
6Hz, 2H), 5.20 (s, 1H), 6.95 (d,
J = 8.8Hz, 2H), 7.49 (d, J = 8.8H
z, 2H), 7.51 (s, 4H) MS m / z 402 (M ⁺ +2, 12), 401 (M
⁺ +1,26), 400 (M ⁺ , 92), 326 (8
0), 214 (100), 213 (43), 57 (2
0), 43 (43), 41 (35), 29 (22) Elemental analysis: C ₂₄ H ₃₂ OS ₂ Calculated: C, 71.95%; H, 8.05%; S, 16.
01% Found: C, 71.81%; H, 8.18%; S, 16.
06%

(1-b) Synthesis of 2-[(4-octyloxyphenyl) methyl] -2- [4- (4-octyloxyphenyl) phenyl] -1,3-dithiane

[0040]

[Chemical 10]

To a solution of 402 mg (1.0 mmol) of 2- [4- (4-octyloxyphenyl) phenyl] -1,3-dithiane in 5 ml of tetrahydrofuran (THF),
0.85M Butyllithium-Hexane solution 0.8 at 78 ° C
ml (1.2 mmol) was added and stirred for 30 minutes. To this reaction solution, 261 mg of 4-octyloxybenzyl chloride (1.
(0 mmol) in THF (2 ml) was added over 2 hours.
The temperature was raised to 30 ° C. Then, it was treated with 2M hydrochloric acid, the reaction product was extracted with ether, and the extract was concentrated. The obtained residue is subjected to column chromatography (Wako Gel C
-200, hexane / ethyl acetate = 20/1) and purified to give 2-[(4-octyloxyphenyl) methyl] -2- [4- (4-octyloxyphenyl) phenyl] -1,3. -Dithiane 575 mg (93% yield) was obtained.

Colorless viscous oily substance IR (neat) 2950, 2880, 1610, 1
510, 1500, 1475, 1250, 1180, 8
_{^{25cm -1 1 H NMR (CDCl 3}} ) δ 0.9 (t, J = 7H
z, 6H), 1.0-2.1 (m, 26H), 2.7
(M, 4H), 3.3 (s, 2H), 3.9 (t, J = 7)
Hz, 2H), 4.0 (t, J = 7Hz, 2H), 6.7
(S, 4H), 7.0 (d, J = 8.5Hz, 2H),
7.5 (d, J = 8.5 Hz, 2H), 7.6 (d, J =
8.5Hz, 2H), 7.7 (d, J = 8.5Hz, 2
H) MS m / z 618 (M ⁺ , 3), 401 (13),
400 (29), 399 (100)

(1-c) 1,1-difluoro-2-
Synthesis of (4-octyloxyphenyl) -1- [4- (4-octyloxyphenyl) phenyl] ethane

[0044]

[Chemical 11]

A solution of 620 mg (2.2 mmol) of tetrabutylammonium dihydrotrifluoride and 425 mg (1.9 mmol) of N-iodosuccinimide (NIS) in 10 ml of dichloromethane was added to 2-[(4-octyl) at -78 ° C. A solution of 425 mg (0.69 mmol) of oxyphenyl) methyl] -2- [4- (4-octyloxyphenyl) phenyl] -1,3-dithiane in 3 ml of dichloromethane was added, and the temperature was raised to -30 ° C over 3 hours. did. Subsequently, the mixture was treated with saturated saline and filtered through Celite, and the reaction product was extracted with ether. The extract was washed with saturated aqueous sodium thiosulfate solution and concentrated, and the obtained residue was subjected to column chromatography (Wakogel C-2
00, hexane / ethyl acetate = 20/1) and purified, 1,1-difluoro-2- (4-octyloxyphenyl) -1- [4- (4-octyloxyphenyl) phenyl] ethane 232 mg (Yield 61%) was obtained.

Phase transition temperature 127 ° C. (Cr → SB), 1
42 ° C. (SB → I) White powder IR (KBr) 2950,2880,1610,15
15, 1480, 1300, 1255, 1210, 11
80,1030,1000,830 cm ^{-1 1} H NMR (CDCl ₃ ) δ 0.9 (t, J = 7H
z, 6H), 1.1-2.1 (m, 24H), 3.4
(T, J = 16Hz, 2H), 3.9 (t, J = 7H
z, 2H), 4.0 (t, J = 7Hz, 2H), 6.76
(D, J = 8.7 Hz, 2H), 6.97 (d, J = 8.
7Hz, 2H), 7.01 (d, J = 8.7Hz, 2
H), 7.33 (d, J = 8.7 Hz, 2H), 7.50
(D, J = 8.7 Hz, 2H), 7.52 (d, J = 8.
7 Hz, 2H) MS m / z 551 (M ⁺ +1, 21), 550 (M
⁺ , 57), 331 (41), 219 (52), 107
(100), 69 (20), 57 (31), 55 (2
2), 43 (57), 41 (35), 29 (22) Elemental analysis: Calculated as C ₃₆ H ₄₈ F ₂ O: C, 78.51%; H, 8.78% Actual value: C, 78 .21%; H, 8.98%

Example 2 1,1-difluoro-1-
Synthesis of (4-heptyloxyphenyl) -2- (4-octyloxyphenyl) ethane (Compound No. 2 in Table 1)

(2-a) Synthesis of 2- (4-heptyloxyphenyl) -1,3-dithiane

[0049]

[Chemical 12]

4-heptyloxybenzaldehyde 1.
03 g (4.7 mmol), propanedithiol 0.58
g (5.4 mmol) and 20 ml of PPSE-dichloromethane solution were stirred at room temperature for 13 hours. After completion of the reaction, 50 ml of saturated aqueous sodium hydrogen carbonate solution was added, and the reaction product was extracted with 100 ml of ether. After the extract was concentrated, the obtained residue was recrystallized from hexane to obtain 1.39 g of 2- (4-heptyloxyphenyl) -1,3-dithiane (yield 96%).

Colorless plate crystal melting point 71 ° C. IR (KBr) 2940,1610,1510,14
75, 1415, 1305, 1260, 1175, 10
30,1020,845,815,765,670 cm ^{−1 1} H NMR (CDCl ₃ ) δ 0.89 (t, J = 7.
0Hz, 3H), 1.1-2.2 (m, 12H), 2.8
~ 3.2 (m, 4H), 3.95 (t, J = 6.5Hz,
2H), 5.1 (s, 1H), 6.85 (d, J = 8.5)
Hz, 2H), 7.35 (d, J = 8.5Hz, 2H) MS m / z 310 (M ⁺ , 46), 236 (5
4), 139 (22), 138 (100), 137 (3
7), 57 (45), 55 (20), 45 (22), 4
3 (41), 41 (59), 29 (38) Elemental analysis: C ₁₇ H ₂₆ OS ₂ Calculated: C, 65.76%; H, 8.44%; S, 20.
65% Found: C, 65.50%; H, 8.40%; S, 20.
85%

(2-b) Synthesis of 2- (4-heptyloxyphenyl) -2-[(4-octyloxyphenyl) methyl] -1,3-dithiane

[0053]

[Chemical 13]

2- (4-heptyloxyphenyl)-
1,3-dithiane 1 g (3.2 mmol) THF 15 ml
2.3 ml (3.6 mmol) of a 1.55 M butyllithium-hexane solution was added to the solution at -78 ° C, and the mixture was stirred for 30 minutes. After completion of the reaction, a solution of 4-octyloxybenzyl chloride 0.95 g (3.7 mmol) in THF 5 ml was added,
The temperature was raised to 0 ° C. over 5 hours. The mixture was treated with 2M hydrochloric acid, the reaction product was extracted with ether, the extract was concentrated, and the obtained residue was subjected to column chromatography (Wakogel C-200, hexane / ethyl acetate = 20).
/ (1) to give 2- (4-heptyloxyphenyl) -2-[(4-octyloxyphenyl) methyl] -1,3-dithiane (1.7 g, yield 100%). .

Colorless viscous oily substance IR (neat) 2930, 2870, 1610, 1
510, 1470, 1245, 1175, 1025, 8
10,800,710 cm ^{-1 1} H NMR (CDCl ₃ ) δ 0.89 (t, J = 7)
Hz, 3H), 0.90 (t, J = 7Hz, 3H), 1.
0-2.1 (m, 24H), 2.7 (m, 4H), 3.2
(S, 2H), 3.9 (t, J = 7Hz, 2H), 4.0
(T, J = 7 Hz, 2H), 6.6 (s, 4H), 6.8
(D, J = 8.5 Hz, 2H), 7.6 (d, J = 8.5)
Hz, 2H) MS m / z 528 (M ⁺ , 2), 310 (21),
309 (100)

(2-c) 1,1-difluoro-1-
Synthesis of (4-heptyloxyphenyl) -2- (4-octyloxyphenyl) ethane

[0057]

[Chemical 14]

Tetrabutylammonium dihydrotrifluoride 2 g (7.0 mmol), NIS 1.4 g (6.
(2 mmol) in 20 ml of dichloromethane at -78 ° C.
2- (4-heptyloxyphenyl) -2-[(4-
A solution of 1.4 g (2.7 mmol) of octyloxyphenyl) methyl] -1,3-dithiane in 15 ml of dichloromethane was added, and the temperature was raised to -30 ° C. Subsequently, this mixed solution was treated with saturated saline and further filtered through Celite, and the reaction product was extracted with ether from the filtrate. The extract was washed with a saturated aqueous sodium thiosulfate solution and concentrated, and the obtained residue was subjected to column chromatography (Wako Gel C-200,
Purification using hexane / ethyl acetate = 20/1),
1,1-difluoro-1- (4-heptyloxyphenyl) -2- (4-octyloxyphenyl) ethane 1.
2 g (yield 98%) was obtained.

Colorless plate crystal melting point 65 ° C. IR (KBr) 2940,2870,1615,15
10, 1480, 1305, 1250, 1180, 11
60, 1110, 1030, 990, 885, 830,
790,760 cm ^{-1 1} H NMR (CDCl ₃ ) δ 0.88 (t, J = 7.
0Hz, 3H), 0.89 (t, J = 6.8Hz, 3
H), 1.2-2.1.5 (m, 18H), 1.75 (qu)
intet, J = 6.6Hz, 2H), 1.77 (qui)
ntet, J = 6.6 Hz, 2H), 3.30 (t, J =
15.6Hz, 2H), 3.90 (t, J = 6.6Hz,
2H), 3.94 (t, J = 6.6Hz, 2H), 6.7
4 (d, J = 8.7 Hz, 2H), 6.83 (d, J =
8.8Hz, 2H), 6.97 (d, J = 8.8Hz, 2
H), 7.21 (d, J = 8.7 Hz, 2H) MS m / z 461 (M ⁺ , 16), 241 (7
5), 219 (52), 143 (69), 107 (10
0), 57 (49), 55 (32), 43 (62), 4
1 (46), 29 (31) Elemental analysis: Calculated as C ₂₉ H ₄₂ F ₂ O: C, 75.62%; H, 9.19% Measured value: C, 75.84%; H, 9. 45%

Example 3 Synthesis of 1- (4-butyloxyphenyl) -1,1-difluoro-2- (4-propylphenyl) ethane (Compound No. 3 in Table 1)

(3-a) Synthesis of 2- (4-butyloxyphenyl) -1,3-dithiane

[0062]

[Chemical 15]

4-Butyloxybenzaldehyde 3.5
g (20 mmol), propanedithiol 2.45 g
(23 mmol), PPSE-dichloromethane solution 40
The ml was stirred at room temperature for 17 hours. After completion of the reaction, 50 ml of saturated aqueous sodium hydrogen carbonate solution was added, and the reaction product was extracted with 100 ml of ether. After concentrating the extract, the obtained residue was recrystallized from a hexane / ether (10/1) mixed solvent to give 2- (4-butyloxyphenyl) -1,
4.6 g (87% yield) of 3-dithiane was obtained.

Colorless plate crystal Melting point 81 ° C. IR (KBr) 2950, 2900, 1610, 15
10, 1480, 1415, 1310, 1460, 11
80,1040,1005,845,810,765,
670,585,525 cm ^{-1 1} H NMR (CDCl ₃ ) δ 0.96 (t, J = 7.
3Hz, 3H), 1.2-2.2 (m, 6H), 2.7-
3.3 (m, 4H), 3.94 (t, J = 6.5Hz, 2
H), 5.12 (s, 1H), 6.85 (d, J = 8.7)
Hz, 2H), 7.38 (d, J = 8.7Hz, 2H), MS m / z 269 (M ⁺ +1, 13), 268.
(M ⁺ , 75), 194 (80), 138 (100),
137 (49), 57 (26), 45 (20), 41
(39), 29 (42) Elemental analysis: C ₁₄ H ₂₀ OS ₂ Calculated: C, 62.64%; H, 7.51%; S, 23.
89% Found: C, 62.63%; H, 7.66%; S, 23.
61%

(3-b) 2- (4-butyloxyphenyl) -2-[(4-propylphenyl) methyl]-
Synthesis of 1,3-dithiane

[0066]

[Chemical 16]

2- (4-butyloxyphenyl) -1,
2.7 g (10 mmol) of 3-dithiane in 25 ml of THF
To the solution was added 8 ml (12 mmol) of a 1.55 M butyllithium-hexane solution at -78 ° C, and the mixture was stirred for 30 minutes. 1.8 g of 4-propylbenzyl chloride was added to this reaction solution.
A solution of (11 mmol) in 5 ml of THF was added and the temperature was raised to 0 ° C. over 5 hours. Subsequently, the mixture was treated with 2M hydrochloric acid, the reaction product was extracted with ether, the extract was concentrated, and the obtained residue was subjected to column chromatography (Wakogel C-200, hexane / ethyl acetate = 20 /).
1) and purified with 2- (4-butyloxyphenyl) -2-[(4-propylphenyl) methyl] -1,
3.7 g (92% yield) of 3-dithiane was obtained.

Colorless viscous oily substance IR (neat) 2970, 1605, 1500, 1
470, 1290, 1245, 1180, 1030, 8
_{^{30,580cm -1 1 H NMR (CDCl 3}} ) δ 0.89 (t, J = 6.
5Hz, 3H), 0.96 (t, J = 7.3Hz, 3
H), 1.2 to 2.2 (m, 8H), 2.4 to 3.0 (6
H), 3.22 (s, 2H), 3.97 (t, J = 6.5)
Hz, 2H), 6.67 (d, J = 8.3Hz, 2H),
6.80 (d, J = 8.7 Hz, 2H), 6.92 (d,
J = 8.3Hz, 2H), 7.56 (d, J = 8.7H
z, 2H) MS m / z 400 (M ⁺ , trace), 267
(100), 137 (24), 133 (39), 91
(13)

(3-c) Synthesis of 1- (4-butyloxyphenyl) -1,1-difluoro-2- (4-propylphenyl) ethane

[0070]

[Chemical 17]

Tetrabutylammonium dihydrotrifluoride 4.6 g (16 mmol), NIS 3.5 g (1
6 mmol) in 30 ml of dichloromethane at -78 ° C.
2.5 g of 2- (4-butyloxyphenyl) -2-[(4-propylphenyl) methyl] -1,3-dithiane
A solution of (6.3 mmol) in 20 ml of dichloromethane was added, and the temperature was raised to 0 ° C over 6 hours. Subsequently, this mixed solution was treated with saturated saline and filtered through Celite, and the reaction product was extracted from the filtrate with a mixed solvent of ether / ethyl acetate (1/1), and then the extracted solution was washed with a saturated aqueous solution of sodium thiosulfate. After washing and concentrating, the obtained residue was purified by column chromatography (Wakogel C-300, hexane / ethyl acetate = 30/1) to give 1- (4-butyloxyphenyl) -1,1-difluoro. 1.45 g (yield 70%) of 2- (4-propylphenyl) ethane was obtained.

Colorless plate-like crystal Melting point 62 ° C. IR (KBr) 2960,2880,1620,15
90, 1520, 1470, 1420, 1380, 13
60, 1300, 1255, 1185, 1155, 11
15, 1070, 1030, 995, 970, 890,
830,770,640,580 cm ^{-1 1} H NMR (CDCl ₃ ) δ 0.91 (t, J = 7.
4Hz, 3H), 0.97 (t, J = 7.4Hz, 3
H), 1.49 (sextet, J = 7.4Hz, 2
H), 1.60 (sextet, J = 7.4Hz, 2
H), 1.76 (quintet, J = 7.4Hz, 2
H), 2.54 (t, J = 7.4Hz, 2H), 3.34
(T, J = 15.8 Hz, 2H), 3.95 (t, J =
7.4Hz, 2H), 6.83 (d, J = 8.8Hz, 2
H), 6.99 (d, J = 8.1 Hz, 2H), 7.05
(D, J = 8.1 Hz, 2H), 7.22 (d, J = 8.
8 Hz, 2H) MS m / z 332 (M ⁺ , 16), 199 (10
0), 143 (94), 29 (25) Elemental analysis: Calculated as C ₂₁ H ₂₆ F ₂ O: C, 75.87%; H, 7.88% Found: C, 75.94%; H , 7.99%

Example 4 1,1-difluoro-2-
(4-Propylphenyl) -1- [4- (trans-4
-Propylcyclohexyl) phenyl] ethane (Compound No. 4 in Table 1)

[0074]

[Chemical 18]

In the same manner as in Example 3 except that 4- (trans-4-propylcyclohexyl) benzaldehyde was used in place of 4-butyloxybenzaldehyde in Example 3, 2- [4- (4- Transformer-4
-Propylcyclohexyl) phenyl] -1,3-dithiane, then 2- [4- (trans-4-propylcyclohexyl) phenyl] -2-[(4-propylphenyl) methyl] -1,3-dithiane, There was obtained 1,1-difluoro-2- (4-propylphenyl) -1- [4- (trans-4-propylcyclohexyl) phenyl] ethane.

2- [4- (4-trans-4-propylcyclohexyl) phenyl] -1,3-dithiane Colorless columnar crystal Melting point 129 ° C. IR (KBr) 2930,1440,1420,12
_{^{75,765cm -1 1 H NMR (CDCl 3}} ) δ 0.90 (t, J = 7.
2Hz, 2H), 0.98 to 1.08 (m, 2H), 1.
15-1.46 (m, 7H), 1.81-1.95 (m,
5H), 2.165 (dm, J = 14.1Hz, 1H),
2.44 (tt, J = 12.2 and 3.2Hz, 1
H), 2.90 (ddd, J = 14.5, 4.2, and
2.4Hz, 2H), 5.14 (s, 1H), 7.16
(D, J = 8.1 Hz, 2H), 7.37 (d, J = 8.
1 Hz, 2H) MS m / z 321 (M ⁺ +1, 17), 320
(M ⁺ , 76), 247 (24), 246 (100),
148 (22), 147 (19), 136 (16), 1
35 (17), 129 (19), 105 (20), 91
(35), 83 (26), 69 (49), 55 (3
1), 45 (32), 43 (25) Elemental analysis: C ₁₉ H ₂₈ S ₂ Calculated value: C, 71.19%; H, 8.80%; S, 20.
01% Found: C, 71.35%; H, 8.95%; S, 20.
07%

2- [4- (trans-4-propylcyclohexyl) phenyl] -2-[(4-propylphenyl) methyl] -1,3-dithiane colorless needles melting point 82 ° C IR (KBr) 2920,1500 , 1440, 14
15,970,835,590 cm ^{-1 1} H NMR (CDCl ₃ ) δ 0.89 (t, J = 7.
4Hz, 3H), 091 (t, J = 7.3Hz, 3
H), 1.00-1.12 (m, 2H), 1.18-1.6
2 (m, 11H), 1.84 to 1.96 (m, 6H),
2.42 to 2.52 (m, 3H), 2.58 to 2.75
(M, 4H), 3.20 (s, 2H), 6.63 (d, J
= 8.1Hz, 2H), 6.89 (d, J = 8.1Hz,
2H), 7.11 (d, J = 8.4Hz, 2H), 7.5
9 (d, J = 8.4 Hz, 2H) MS m / z 452 (M ⁺ , 1), 319 (100) Elemental analysis: Calculated as C ₂₉ H ₄₀ S ₂ : C, 76.93%; H, 9.91%; S, 14.
16% Found: C, 77.11%; H, 9.14%; S, 14.
39%

1,1-difluoro-2- (4-propylphenyl) -1- [4- (trans-4-propylcyclohexyl) phenyl] ethane colorless powder melting point 76 ° C IR (KBr) 2950,1360,1265,10
30, 1000, 890, 830, 770, 590 cm ^{-1 1} H NMR (CDCl ₃ ) δ 0.90 (t, J = 7.
3Hz, 3H), 092 (t, J = 7.3Hz, 3
H), 0.98 to 1.12 (m, 2H), 1.18 to 1.5
0 (m, 7H), 1.61 (sextet, J = 7.3H
z, 2H), 1.83-1.92 (m, 4H), 2.47.
(Tt, J = 12.2 and 3.0 Hz, 1H), 2.5
5 (t, J = 7.3 Hz, 2H), 3.34 (t, J = 1
6.3 Hz, 2 H), 7.03 (d, J = 8.4 Hz, 2
H), 7.06 (d, J = 8.4 Hz, 2H), 7.18
(D, J = 8.4 Hz, 2H), 7.26 (d, J = 8.
4 Hz, 2H) MS m / z 384 (M ⁺ , 5), 251 (10
0), 133 (21), 127 (21) Elemental analysis: C ₂₆ H ₃₄ F ₂ Calculated: C, 81.21%; H, 8.91% Found: C, 81.01%; H, 9.03%

Example 5 Preparation of Nematic Liquid Crystal Composition

[0080]

[Chemical 19]

When a nematic matrix liquid crystal (A) consisting of was prepared, it showed a nematic phase at 50.5 ° C. or lower.
The physical properties of the host liquid crystal (A) at 20 ° C. were measured and the results were as follows. Birefringence anisotropy (Δn) 0.117 Threshold voltage (V) 1.50 Dielectric anisotropy 12.0 90% of the host liquid crystal (A) and the formula obtained in Example 3

[0082]

[Chemical 20]

Liquid crystal composition (M) comprising 10% of the compound of
Was prepared, it exhibited a nematic phase at 34.5 ° C. or lower. The physical properties of this liquid crystal composition (M) at 20 ° C. measured in the same manner as above were as follows. Birefringence anisotropy (Δn) 0.077 Threshold voltage (V) 1.05 Dielectric anisotropy 9.4

From the above results, the compound represented by the general formula (I) of the present invention was found to have the birefringence anisotropy (Δn) of the host liquid crystal.
Can be understood to be effectively reduced.

Example 6 Preparation of Ferroelectric Liquid Crystal Composition

[0086]

[Chemical 21]

A matrix liquid crystal (B) having an SC phase consisting of was prepared. This matrix liquid crystal (B) 84% and

[0088]

[Chemical formula 22]

A ferroelectric liquid crystal composition (hereinafter abbreviated as SC ^* liquid crystal composition) (F-1) containing 16% of a chiral dopant (P) was prepared.

The SC ^* liquid crystal composition (F-1) had a composition of 66.5.
Shows SC ^* phase below ℃, SA (smectic A) phase below 69 ℃, N ^* (chiral nematic) below 75 ℃
It showed a phase and became an I (isotropic liquid) phase at higher temperatures.

Using this SC ^* liquid crystal composition (F-1),
A liquid crystal display device was prepared as follows. Coated with polyimide and rubbed with nylon cloth 2
A glass transparent electrode plate was attached to each other via glass fiber beads having a particle diameter of 2 μm to prepare a cell. The SC ^* liquid crystal composition (F-1) was sealed in this cell in a state of being heated to the I phase, and then gradually cooled to room temperature to obtain N ^*.
Phase, SA phase and then SC ^* were oriented to obtain a uniformly oriented liquid crystal display element having a thickness of about 2 μm. A rectangular wave of 50 Hz with an electric field strength of 10 V _PP / μm was applied to this liquid crystal display element, and its electro-optical response speed was measured.
It was 46 microseconds at ° C. The spontaneous polarization at this time is 17.
The contrast was 6 nC / cm ² , the tilt angle was 29.5 °, and the contrast was good.

Next, 90% of the base liquid crystal (B) and Example 1
Expression obtained by

[0093]

[Chemical formula 23]

A host liquid crystal (C) consisting of 10% of the compound of was prepared.

An SC ^* liquid crystal composition (F-2) comprising 84% of the base liquid crystal (C) and 16% of the above chiral dopant (P) was prepared. This SC ^* liquid crystal composition (F-
The maximum temperature of the SC ^* phase in 2) was 68.5 ° C, which was 2 ° C higher than that of the SC ^* liquid crystal composition (F-1). Also, 69
The SA phase was shown at a temperature of 75 ° C or lower, the N ^* phase was shown at a temperature of 75 ° C or lower, and the I phase was obtained at a temperature higher than that.

Using this SC ^* liquid crystal composition (F-2),
A liquid crystal display device was prepared in the same manner. The electro-optical response speed measured in the same manner was 47 μs at 25 ° C. and SC ^*
There was almost no change from the case of the liquid crystal composition (F-1). At this time, the spontaneous polarization was 17.2 nC / cm ² , the tilt angle was 27.7 °, and the contrast was good.

From the above results, it is possible to extend the driving temperature range to a high temperature range by adding the compound represented by the general formula (I) without changing the response of the ferroelectric liquid crystal composition. Can be understood to show.

[0098]

The compound represented by the general formula (I) according to the present invention has excellent compatibility with the host liquid crystal which is currently widely used as a nematic liquid crystal, and when added in a small amount, its birefringent anisotropic It is possible to effectively reduce the sex (Δn). In addition, the compound represented by the general formula (I) is added as a constituent component of the host liquid crystal to a liquid crystal composition exhibiting ferroelectricity in a small amount, so that its driving temperature range can be kept in a high temperature range while maintaining its high-speed response. Can be expanded to. Therefore, the compound represented by the general formula (I) of the present invention is useful as a material for various liquid crystal display cells.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication C09K 19/42 6742-4H 19/58 6742-4H (72) Inventor Haruyoshi Takatsu Nakamachi, Kodaira-shi, Tokyo 500-14 (72) Inventor Kiyofumi Takeuchi 1-12-14-103 Takashimadaira Itabashi-ku, Tokyo (72) Inventor Taijiro Hiyama 4-29-3-101 Kamizuruma, Sagamihara City, Kanagawa (72) Inventor Tetsuo Kusumoto 1-9-2-102 Minamidai, Sagamihara-shi, Kanagawa Prefecture (72) Inventor Kenichi Sato 35-11, Kamizomi, Sagamihara-shi, Kanagawa Prefecture (72) Akiko Nakayama 1380-K-702 (72) inventor, Yamazaki-cho, Machida-shi, Tokyo Kuroboshi Gaku 4-4-1 Nishionuma, Sagamihara City, Kanagawa Prefecture

Claims (3)

[Claims] 1. A compound represented by the general formula (I): (In the formula, R ¹ and R ² each independently represent an alkyl group or an alkoxyl group having 1 to 16 carbon atoms, and the ring A represents a 1,4-phenylene group or a trans-1,4-cyclohexylene group. , M represents 0 or 1, and n represents 1
Or represents 2. ) The compound represented by. 2. The compound according to claim 1, wherein n = 1. 3. A liquid crystal composition containing the compound according to claim 1.