JPH1067708A - 2-Methylsuccinic acid diester compound, liquid crystal composition containing the same, and method for producing this compound - Google Patents

Abstract

(57) [Summary] [PROBLEMS] By adding a small amount to a ferroelectric liquid crystal composition,
Sm without affecting other physical constants such as spontaneous polarization
A 2-methyl succinic diester compound or an optically active substance thereof, which can adjust the helical pitch of the C ^* phase and the Ch phase, significantly weaken the layer structure of the smectic phase, and easily induce a change in the orientation direction of the smectic phase, and Provided are a liquid crystal composition containing the same, and a method for producing the compound. SOLUTION: The following general formula (1): (Wherein A and B represent hard groups and R ₁ and R ₂ represent soft groups), and at least one or more of these optically active isomers of the cholesteric phase Alternatively, a liquid crystal composition comprising a liquid crystal material exhibiting a chiral smectic C phase.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel 2-methylsuccinic acid diester compound or an optically active compound thereof, a liquid crystal composition containing at least one of them, and a method for producing these compounds.

[0002] The 2-methylsuccinic acid diester compound is extremely useful as a liquid crystal material constituting an optoelectronics-related element such as a display, a recording element, a light valve or a projector.

[0003]

2. Description of the Related Art In recent years, display devices utilizing the optical switching phenomenon of ferroelectric liquid crystals have been proposed by NA Clark and ST Lagerwall [Applied Phys. Lett.,
36 , 899 (1980)]. An element using this ferroelectric liquid crystal has bistability, and has a conventional TN type or ST type.
It has an excellent feature that the optical response is on the order of μsec and is faster than that of a liquid crystal element of a display method called N-type.

In order to obtain good contrast in this ferroelectric liquid crystal device, the liquid crystal composition must be formed by (1)
It is necessary to take a phase sequence of-cholesteric (Ch) phase-smectic A (SmA) phase-chiral smectic C (SmC ^* ) phase, and (2) lengthen the helical pitch of the Ch phase and SmC ^* phase. . Further, in order to increase the response speed of the ferroelectric liquid crystal composition to an electric field, the composition is required to be (3)
It is required to have a large spontaneous polarization (Ps).

[0005] A ferroelectric liquid crystal composition can be prepared by adding an optically active compound to a non-chiral base liquid crystal.
In order to obtain a composition having a fast response to an electric field and a good contrast, it is necessary to satisfy the above three conditions. Therefore, the optically active compound added as an additive is large in the SmC ^* phase. Spontaneous polarization and Ch
It is necessary not to induce short helical pitches in the phase and the SmC ^* phase. However, in general, a molecular structure that exhibits large spontaneous polarization has a property of inducing a short helical pitch in the Ch phase and the SmC ^* phase. Therefore, when attempting to increase the spontaneous polarization by adding an optically active compound to create a composition having a high response speed, a short helical pitch is induced in the Ch phase and the SmC ^* phase, and good contrast cannot be obtained. Will be.

The spiral in the Ch phase and the SmC ^* phase has a left direction and a right direction, and the spontaneous polarization has two directions, a + direction and a-direction. When a compound having the same spontaneous polarization direction and the opposite helical direction is added, the helical pitch becomes longer. However, since the direction of the helix and the direction of the spontaneous polarization generally change in pairs depending on the molecular structure of the optically active compound, it is difficult to make a compound in which one direction is reversed due to inversion of the absolute configuration. is there. Therefore, in order to increase the helical pitch in order to obtain a good contrast, when a compound having a helical direction opposite to that of a compound is added, the spontaneous polarization is generally canceled out, and the response speed to the electric field is reduced. Become slow.

[0007] Therefore, a compound which has little effect on spontaneous polarization and can induce a short helical pitch is desired as a helical pitch regulator. In addition, the shorter the helical pitch of the compound, the longer the helical pitch with a small amount of addition.

As such a compound, the following general formula (6) having an asymmetric carbon in the central spacer portion:

Embedded image (Wherein, R represents an alkyl group and C ^* represents an asymmetric carbon in which optical activity has been induced) 3-methyladipate diesters (J. Mater. Chem., 1994, 4, p449 and Japanese Unexamined Patent Publication No. Hei 6-306055) has been proposed.

However, although this general formula (6) induces a short helical pitch, it has a drawback that the response speed of the ferroelectric liquid crystal is slowed. Therefore, another compound that induces a shorter helical pitch is required.

On the other hand, a smectic liquid crystal has a layer structure different from a nematic liquid crystal, and the layer structure changes when an electric field or a magnetic field is applied from the outside, and the molecules rearrange accordingly. By observing this change as a change in the amount of transmitted light, the smectic liquid crystal can be used as an optoelectronics-related element such as a display, a recording element, a light valve, and a projector, like the nematic liquid crystal. However, in order to cause a change in the layer structure and molecular arrangement of this smectic liquid crystal,
Although it is necessary to apply a stronger external electric field, etc., compared to causing a change in the molecular arrangement of the nematic liquid crystal having no layer structure, by adding a compound that induces a short helical pitch, It is expected that the deformation of the layer structure and the change of the molecular arrangement by the application of an electric field or the like can be facilitated. For such applications, there is a demand for a compound that induces a shorter helical pitch.

[0011]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and an object of the present invention is to add a small amount to a ferroelectric liquid crystal composition to affect other physical constants such as spontaneous polarization. A novel compound that can adjust the helical pitch of the SmC ^* phase and Ch phase without giving any effect, significantly weakens the layer structure of the smectic phase, and can easily induce a change in the orientation direction of the smectic phase, and a liquid crystal containing the same. It is an object of the present invention to provide a composition as well as a process for producing this compound.

[0012]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, compared with the 3-methyladipate diesters represented by the above-mentioned general formula (6), the center of the present invention has been improved. An optically active 2-methylsuccinic diester compound with a short spacer is strong in the twisting power of the helix, but very weak in spontaneous polarization. The helical pitch of the SmC ^* phase and the Ch phase can be adjusted without affecting the physical constants of SmC ^* and the 2-methylsuccinate diester compound forms a cross-linked structure between the smectic layers. It has been found that the layer structure is significantly weakened, and as a result, a change in the orientation direction of the smectic phase can be easily induced by applying a weaker electric field from the outside.

That is, the present invention provides the following general formula (1)

Embedded image (Wherein A and B represent hard groups and R ₁ and R ₂ represent soft groups), and the carbonyl group and the methyl group in the above formula are bonded to the 2-methylsuccinic acid diester compound An optically active substance having an asymmetric center on methine carbon, and at least one or more of the above-mentioned 2-methylsuccinic acid diester compound or its optically active substance were added to a liquid crystal material exhibiting a cholesteric phase or a chiral smectic C phase. And a liquid crystal composition mixed with 4-cyano-4'-alkylbiphenyl or 4-cyano-4'-alkoxybiphenyl exhibiting a smectic phase.

The compound of the above general formula (1) enters into the layer structure of the base liquid crystal and causes a strongly twisted interaction in the adjacent layer. Therefore, A in this compound
And B may have a structure which is the same as or similar to the core portion of the base liquid crystal, which is easily called into the layer structure of the base liquid crystal, that is, a so-called rigid group, such as phenyl, biphenyl, phenylpyrimidine, phenyl benzoate, Groups such as cyclohexane, cyclohexylphenyl, phenylcyclohexanecarboxylate, cyclohexylbenzoate, phenylpyridine, phenylbiphenylcarboxylate, biphenylbenzoate, terphenyl, and phenylpyrimidinylphenyl are preferred. A and B may be the same or different groups, but are preferably the same group because of ease of synthesis.

In these formulas, R ₁ and R ₂ affect the phase transition temperature of the liquid crystal, but do not have a great influence on the induction of the helical structure. For example, an alkyl group, an alkoxy group, an alkenyloxy group, a cyano group, a nitro group, fluorine, and the like are preferable. The alkyl group, the alkoxy group, and the alkenyloxy group have 1 to 1 carbon atoms because of availability of raw materials. 18, particularly preferably those having 3 to 10 carbon atoms. R ₁ and R ₂ may be the same or different groups, but are preferably the same group because of ease of synthesis.

Further, the present invention provides a compound represented by the following general formula (2):

Embedded image (Wherein m represents an integer of 1 to 18, and C ^* represents an asymmetric carbon to which optical activity has been imparted).
Methyl succinic acid diester compound and the following general formula (3)

Embedded image (Wherein m represents an integer of 1 to 18), wherein the above-mentioned general formula comprises esterifying 5-alkyl-2- (4-hydroxyphenyl) pyrimidine and optically active 2-methylsuccinic acid. A method for producing an optically active 2-methylsuccinic acid diester compound represented by (2),
The following general formula (4)

Embedded image (Wherein X represents a cyano group, a nitro group, fluorine or chlorine), and an optically active 2-methylsuccinic acid diester compound represented by the following general formula (5):

Embedded image (Wherein X represents a cyano group, a nitro group, fluorine or chlorine), and the above-mentioned general formula (4) comprising esterifying 4-hydroxybiphenyls represented by the formula and optically active 2-methylsuccinic acid. This is a method for producing the optically active 2-methylsuccinic acid diester compound represented.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION As the compound represented by the general formula (1) of the present invention, specifically, di- (4- (5-pentylpyrimidin-2-yl) phenyl) 2-methylsuccinate is used.
Ester, 2-methylsuccinic acid di- (4- (5-hexylpyrimidin-2-yl) phenyl) ester, 2-methylsuccinic acid di- (4- (5-heptylpyrimidin-2-yl) phenyl) ester, 2-methylsuccinic acid di- (4- (5-octylpyrimidin-2-yl) phenyl) ester, 2-methylsuccinic acid di- (4- (5-nonylpyrimidin-2-yl) phenyl) ester, 2-methylsuccinic acid Methyl succinic acid di- (4- (5-decylpyrimidin-2-yl) phenyl) ester, 2-methylsuccinic acid di- (4- (5-dodecylpyrimidin-2-yl) phenyl) ester, 2-methyl succinic acid Acid di- (4-butyloxyphenyl) ester, 2-methylsuccinic acid di- (4-pentyloxyphenyl) ester, 2-methylsuccinic acid di-
(4-hexyloxyphenyl) ester, 2-methylsuccinic acid di- (4-heptyloxyphenyl) ester, 2-methylsuccinic acid di- (4-octyloxyphenyl) ester, 2-methylsuccinic acid di- (4 -Nonyloxyphenyl)
Ester, 2-methylsuccinic acid di- (4-decyloxyphenyl) ester, 2-methylsuccinic acid di- (4-dodecyloxyphenyl) ester, 2-methylsuccinic acid di- (4-
Hexylphenyl) ester, 2-methylsuccinic acid di-
(4-heptylphenyl) ester, 2-methylsuccinic acid
Di- (4-octylphenyl) ester, 2-methylsuccinic acid di- (4-nonylphenyl) ester, 2-methylsuccinic acid di- (4-decylphenyl) ester, 2-methylsuccinic acid di- (4- Dodecylphenyl) ester, 2-methylsuccinic acid di- (4-cyanophenyl) ester, 2-methylsuccinic acid di- (4-fluorophenyl) ester, 2-methylsuccinic acid di-4- (4'-cyanobiphenyl ) Ester, 2-methylsuccinic acid di-4- (4'-nitrobiphenyl) ester, 2-methylsuccinic acid di-4- (4'-fluorobiphenyl) ester, 2-methylsuccinic acid di-4- (4 '-Hexyloxybiphenyl) ester, 2-methylsuccinic acid di-4
-(4'-heptyloxybiphenyl) ester, 2-methylsuccinic acid di-4- (4'-octyloxybiphenyl) ester, 2-methylsuccinic acid di-4- (4'-decyloxybiphenyl) ester, 2 -Methylsuccinic acid di-4- (4'-dodecyloxybiphenyl) ester, 2-methylsuccinic acid di-4- (4'-hexylbiphenyl) ester, 2-methylsuccinic acid di-4- (4'-heptyl) Biphenyl) ester,
2-methylsuccinic acid di-4- (4'-octylbiphenyl) ester, 2-methylsuccinic acid di-4- (4'-nonylbiphenyl) ester, 2-methylsuccinic acid di-4- (4'-decyl) Biphenyl) ester, 2-methylsuccinic acid di-4- (4'-
Dodecylbiphenyl) ester, 2-methylsuccinic acid di-
(4- (4-hexylphenylcarbonyloxy) phenyl)
Ester, 2-methylsuccinic acid di- (4- (4-heptylphenylcarbonyloxy) phenyl) ester, 2-methylsuccinic acid di- (4- (4-octylphenylcarbonylcarbonyl) phenyl) ester, 2-methylsuccinic acid Acid di- (4-
(4-Nonylphenylcarbonyloxy) phenyl) ester, 2-methylsuccinic acid di- (4- (4-decylphenylcarbonyloxy) phenyl) ester, 2-methylsuccinic acid di- (4- (4-dodecylphenylcarbonyl) (Oxy) phenyl) ester, 2-methylsuccinic acid di- (4- (4-hexyloxyphenylcarbonyloxy) phenyl) ester, 2-methylsuccinic acid di- (4- (4-heptyloxyphenylcarbonyloxy) phenyl) Ester, 2-methylsuccinic acid di- (4- (4-octyloxyphenylcarbonyloxy) phenyl) ester, 2-methylsuccinic acid
-(4- (4-nonyloxyphenylcarbonyloxy) phenyl) ester, 2-methylsuccinic acid di- (4- (4-decyloxyphenylcarbonyloxy) phenyl) ester,
2-methylsuccinic acid di- (4- (4-dodecyloxyphenylcarbonyloxy) phenyl) ester, 2-methylsuccinic acid di- (4- (4-hexylphenyloxycarbonyl) phenyl) ester, 2-methylsuccinic acid Di- (4- (4
-Heptylphenyloxycarbonyl) phenyl) ester, 2-methylsuccinic acid di- (4- (4-octylphenyloxycarbonyl) phenyl) ester, 2-methylsuccinic acid di- (4- (4-nonylphenyloxycarbonyl) Phenyl) ester, 2-methylsuccinic acid di- (4- (4-decylphenyloxycarbonyl) phenyl) ester, 2-methylsuccinic acid
Methyl succinic acid di- (4- (4-dodecylphenyloxycarbonyl) phenyl) ester, 2-methyl succinic acid di-
(4- (4-hexyloxyphenyloxycarbonyl) phenyl) ester, 2-methylsuccinic acid di- (4- (4-heptyloxyphenyloxycarbonyl) phenyl) ester, 2-methylsuccinic acid di- (4- ( 4-octyloxyphenyloxycarbonyl) phenyl) ester, 2-methylsuccinic acid di- (4- (4-nonyloxyphenyloxycarbonyl) phenyl) ester, 2-methylsuccinic acid di-
(4- (4-decyloxyphenyloxycarbonyl) phenyl) ester, 2-methylsuccinic acid di- (4- (4-dodecyloxyphenyloxycarbonyl) phenyl) ester, 2-methylsuccinic acid di- (4- ( 4-cyanophenyloxycarbonyl) phenyl) ester, 2-methylsuccinic acid di- (4- (4-nitrophenyloxycarbonyl) phenyl) ester, 2-methylsuccinic acid di- (4- (4-fluorophenyloxycarbonyl) ) Phenyl) ester, 2-
Methyl succinic acid di- (4- (4-hexylcyclohexyl)
Phenyl) ester, 2-methylsuccinic acid di- (4- (4-pentylcyclohexyl) phenyl) ester, 2-methylsuccinic acid di- (4- (4-butylcyclohexyl) phenyl)
Ester, 2-methylsuccinic acid di- (4- (4-propylcyclohexyl) phenyl) ester, 2-methylsuccinic acid
Di- (4-propylcyclohexyl) ester, 2-methylsuccinic acid di- (4-butylcyclohexyl) ester, 2-
Methylsuccinic acid di- (4-pentylcyclohexyl) ester, 2-methylsuccinic acid di- (4-hexylcyclohexyl) ester, 2-methylsuccinic acid di- (4- (4′-hexyloxybiphenyl-4-yl-yl) Carbonyloxy) phenyl) ester, 2-methylsuccinic acid di- (4- (4′-heptyloxybiphenyl-4-yl-carbonyloxy) phenyl) ester, 2-methylsuccinic acid di- (4- (4′- Octyloxybiphenyl-4-yl-carbonyloxy) phenyl) ester, 2-methylsuccinic acid di (4- (4'-nonyloxybiphenyl-4-yl-carbonyloxy) phenyl) ester, 2-methylsuccinic acid -(4- (4'-decyloxybiphenyl-4-yl-carbonyloxy) phenyl) ester, 2-methylsuccinic acid di- (4- (4'-dodecyloxybiphenyl-4-yl-carbonyloxy) phenyl) D Di- (4- (4'-hexylbiphenyl-4-yl-carbonyloxy) phenyl) ester 2-methylsuccinate, di- (4- (4'-heptylbiphenyl-4-yl) -2-methylsuccinate -Carbonyloxy) phenyl) ester,
2-methylsuccinic acid di- (4- (4'-octylbiphenyl-
4-yl-carbonyloxy) phenyl) ester, 2-methylsuccinic acid di- (4- (4′-nonylbiphenyl-4-yl-
Carbonyloxy) phenyl) ester, 2-methylsuccinic acid di- (4- (4′-decylbiphenyl-4-yl-carbonyloxy) phenyl) ester, 2-methylsuccinic acid di-
(4- (4'-dodecylbiphenyl-4-yl-carbonyloxy) phenyl) ester, 2-methylsuccinic acid di- (4 "-
(4-hexylphenyloxycarbonyl) biphenyl-4
-Yl) ester, 2-methylsuccinic acid di- (4 "-(4-heptylphenyloxycarbonyl) biphenyl-4-yl) ester, 2-methylsuccinic acid di- (4"-(4-octylphenyloxycarbonyl) ) Biphenyl-4-yl) ester,
2-methylsuccinic acid di- (4 "-(4-nonylphenyloxycarbonyl) biphenyl-4-yl) ester, 2-methylsuccinic acid di- (4"-(4-decylphenyloxycarbonyl) biphenyl-4- Yl) ester, 2-methylsuccinic acid
Di- (4 "-(4-dodecylphenyloxycarbonyl) biphenyl-4-yl) ester, 2-methylsuccinic acid di- (4"
-(4-hexyloxyphenyloxycarbonyl) biphenyl-4-yl) ester, 2-methylsuccinic acid di- (4 "-
(4-heptyloxyphenyloxycarbonyl) biphenyl-4-yl) ester, 2-methylsuccinic acid di- (4 "-
(4-octyloxyphenyloxycarbonyl) biphenyl-4-yl) ester, 2-methylsuccinic acid di- (4 "-
(4-Nonyloxyphenyloxycarbonyl) biphenyl-4-yl) ester, 2-methylsuccinic acid di- (4 "-(4
-Decyloxyphenyloxycarbonyl) biphenyl-
4-yl) ester, 2-methylsuccinic acid di- (4 "-(4-dodecyloxyphenyloxycarbonyl) biphenyl-4
-Yl) ester, 2-methylsuccinic acid di- (4 "-(4-cyanophenyloxycarbonyl) biphenyl-4-yl) ester, 2-methylsuccinic acid di- (4"-(4-nitrophenyloxycarbonyl) ) Biphenyl-4-yl) ester, 2-
Methyl succinic acid di- (4 "-(4-fluorophenyloxycarbonyl) biphenyl-4-yl) ester, 2-methyl succinic acid di- (4- (4-propylcyclohexylcarbonyloxy) phenyl) ester, 2-methyl Succinic acid di-
(4- (4-butylcyclohexylcarbonyloxy) phenyl) ester, 2-methylsuccinic acid di- (4- (4-pentylcyclohexylcarbonyloxy) phenyl) ester, 2-methylsuccinic acid di- (4- (4- (4- Hexylcyclohexylcarbonyloxy) phenyl) ester, 2-methylsuccinic acid di- (4- (2- (4-butyloxyphenyl) pyrimidin-5-yl) phenyl) ester, 2-methylsuccinic acid di- (4- ( 2- (4-pentyloxyphenyl) pyrimidin-5-yl) phenyl) ester, 2-methylsuccinic acid
Di- (4- (2- (4-hexyloxyphenyl) pyrimidine-
5-yl) phenyl) ester, 2-methylsuccinic acid di-
(4- (2- (4-heptyloxyphenyl) pyrimidine-5-
Yl) phenyl) ester, 2-methylsuccinic acid di- (4-
(2- (4-octyloxyphenyl) pyrimidin-5-yl)
Phenyl) ester, 2-methylsuccinic acid di- (4 "-butyl-p-terphenyl-4-yl) ester, 2-methylsuccinic acid di- (4" -pentyl-p-terphenyl-4-yl) ester Ester, 2-methylsuccinic acid di- (4 "-hexyl-p-terphenyl-4-yl) ester, 2-methylsuccinic acid di- (4"
-Heptyl-p-terphenyl-4-yl) ester, di- (4 "-cyano-p-terphenyl-4-yl) -2-methylsuccinate
Examples include esters.

The optically active compound of the compound represented by the general formula (1) can be used as a helical pitch adjusting material for a liquid crystal composition. Further, by adding the compound to a non-ferroelectric liquid crystal composition, a ferroelectric liquid crystal can be obtained, which can be used as a so-called chiral dopant. When this compound is used as a helical pitch adjuster, it depends on the direction of the helix and the strength of the helix of the base liquid crystal.
When used as a chiral dopant in the range of 5 to 20% by weight, it is preferably used in the range of 0.5 to 30% by weight based on the base liquid crystal.

The compound represented by the above general formula (1), when added to a liquid crystal exhibiting a smectic A (SmA) phase, significantly weakens the layer structure of the smectic phase,
As a result, a change in the orientation direction of the smectic phase can be easily induced by applying a weaker electric field. In this case, the addition amount is 0.5 to 50% by weight with respect to the smectic liquid crystal, and preferably 0.5 to 3% by weight from the balance between the effect of weakening the layer structure and the stability of the smectic phase.
0% by weight, particularly preferably in the range of 0.5 to 10% by weight. The physicochemical properties of typical compounds of the present invention are shown below.

(R) -2-methylsuccinic acid di- (4- (5-octane)
Tylpyrimidin- 2-yl) phenyl) ester ¹ H-NMR (270 MHz, CDCl ₃ , TMS standard, δ): 0.88 (t, J =
6.5Hz, 6H), 1.2-1.4 (m, 20H), 1.51 (d, J = 6.8Hz, 3
H) 1.6-1.7 (m, 4H), 2.62 (t, J = 7.6Hz, 4H), 2.
8-2.9 (m, 1H), 3.1-3.2 (m, 1H), 3.2-3.4 (m, 1H)
H), 7.22 (d, J = 7.8 Hz, 4H), 8.45 (d, J = 8.6 Hz, 4H),
8.61 (s, 4H) IR (KBr, cm- ¹ ): 2920, 2840, 1750, 15
80, 1425, 1190, 1130, 790 MS (m / z): 664 [M ⁺ ], 381, 284, 185

(R) -2-methylsuccinic acid di-4- (4′-sia
Nobiphenyl ) ester ¹ H-NMR (270 MHz, CDCl ₃ , TMS standard): 1.52 (d, J = 6.8H
z, 3H), 2.8-3.0 (m, 1H), 3.0-3.2 (m, 1H), 3.
2 to 3.4 (m, 1H), 7.1 to 7.3 (m, 4H), 7.5 to 7.8
(m, 12H) IR (KBr, cm ^-1 ): 3080, 2990, 2230, 17
55, 1605, 1520, 1495, 1395, 12
92, 1170, 1125, 842, 812, 785 MS (m / z): 486 [M ⁺ ], 292

The ester compound represented by the above general formula (1) is obtained by combining 2-methylsuccinic acid with a hydroxy compound comprising a hard group and a soft group corresponding to an alcohol residue of the ester compound, and N, N -It is obtained by diesterification in the presence of a dehydrating agent such as dicyclohexylcarbodiimide. In addition, 2-methylsuccinic acid is commercially available and can be easily obtained.

5-Alkyl-2- represented by the general formula (3)
(4-Hydroxyphenyl) pyrimidine can be synthesized, for example, by reacting 4-hydroxybenzamidine with a Bielsmeier reagent using a commercially available reagent as a starting material [Journal of Prakt. Chem., 317, 617 (197
Five)〕. Further, 4-hydroxybiphenyls represented by the general formula (5) are commercially available and can be easily obtained.

[0024]

【Example】

Example 1 (R) -2-methylsuccinic acid di- (4- (5-octylpyrimidi)
Down 2-yl) phenyl) ester synthesis of 5-octyl-2- (4-hydroxyphenyl) pyrimidine 1.4283g of (5 mmol) was suspended in methylene chloride 20 ml,
0.264 mg (2 mmol) of (R) -2-methylsuccinic acid was added thereto,
24.4 mg (0.2 mmol) of 4-dimethylaminopyridine and 1.03 g of N, N-dicyclohexylcarbodiimide (5 m
mol) and stirred at room temperature for 7 hours. The solid was removed from the reaction mixture by filtration, the filtrate was concentrated and solidified, and the obtained solid was purified by silica gel column chromatography using a mixed solution of methylene chloride / ethyl acetate (40/1) as a developing solvent. This was recrystallized from ethanol to give 1.064 g of the title compound having the aforementioned physicochemical properties and a purity of 100%.
(80% yield). Specific rotation [α] of this compound ^D ₂₅
Was _{-58 (c = 5, CHCl 3} ).

Evaluation of Liquid Crystallinity The phase transition temperature of (R) -2-methylsuccinic acid di- (4- (5-octylpyrimidin-2-yl) phenyl) ester obtained above was measured at the time of cooling. . Liquid is 11
Crystallized directly at 5 ° C.

Further, four kinds of 5-alkyl groups having different alkyl chain lengths are used.
The above compound was added to a liquid crystal composition composed of alkyl-2- (4-alkyloxyphenyl) pyrimidine in an amount of 2% by weight, and the mixture was injected into a glass cell having a cell thickness of 300 μm, and oriented in parallel with the glass substrate to form a spiral. When the line width corresponding to the pitch was directly measured with an optical microscope,
A spiral pitch as short as 1 μm was observed in the m and SmC ^* phases.

On the other hand, the spontaneous polarization in the SmC ^* phase is determined by a triangular wave method [Miyasato et al., Jpn. J. Appl. Phys., 22, L6.
61 (1983)], it can be seen that the compound of the present invention hardly affected the spontaneous polarization below the lower limit of measurement.

(Example 2) ( R) -2-methylsuccinic acid di-4- (4'-cyanobiphenyl)
L) Ester synthesis In Example 1, synthesis was carried out in the same manner as in Example 1 except that 5-octyl-2- (4-hydroxyphenyl) pyrimidine was replaced with 4-cyano-4'-hydroxybiphenyl.
2.2 g (yield 60%) of the title compound having the aforementioned physicochemical properties and a purity of 99.1% was obtained. The specific rotation [α] ^D ₂₅ of this compound was −81 (c = 1, CHCl ₃ ).

Evaluation of Liquid Crystallinity The phase transition temperature of (R) -2-methylsuccinic acid di-4- (4'-cyanobiphenyl) ester obtained above at the time of cooling was measured. The liquid became a cholesteric phase at 176 ° C and crystallized at 116 ° C.

When the line width corresponding to the helical pitch was directly measured by an optical microscope in the same manner as in Example 1,
A helical pitch as short as 3 μm was observed in the phase.

On the other hand, when the spontaneous polarization in the SmC ^* phase was measured by a method similar to that shown in Example 1, it was found that the compound of the present invention hardly affected the spontaneous polarization below the lower limit of measurement. all right.

Comparative Example 1 Di- (4- (5-octylpyrimi ) ( R) -3-methyladipate
(Gin-2-yl) phenyl) ester (R) -2-methylsuccinic acid was synthesized in the same manner as in Example 1 except that (R) -3-methyladipic acid was replaced with (R) -3-methyladipic acid.

The phase transition temperature of this compound was consistent with the value described in the literature. Further, 5% by weight of the above compound was added to a liquid crystal composition comprising four kinds of 5-alkyl-2- (4-alkyloxyphenyl) pyrimidines having different alkyl chain lengths, and this was spirally formed by the method described in Example 1. When the pitch was measured, it was 2 μm in the Ch phase and 2 μm in the SmC ^* phase.

Example 3 Three kinds of cyanobiphenyl compounds shown in Table 1 were mixed in the proportions shown in Table 1 to prepare a composition A for forming a smectic liquid crystal structure.

[0035]

[Table 1]

A liquid crystal composition B was prepared by adding 2% by weight of the compound of Example 1 to this composition A.

The phase transition temperature of these compositions at the time of cooling is as follows:
As shown in Table 2, both showed smectic A phase at room temperature.

[0038]

[Table 2]

In order to examine the strength of the layer structure of the smectic phase of this liquid crystal composition B, these compositions were treated with ITO.
Having a film and a polyimide alignment film and subjected to a rubbing treatment 2
The mixture was injected into a cell having a thickness of 3 μm formed of two glass plates, and the smectic A phase was oriented in parallel. An electric field was applied to each of these cells at room temperature, and a change in the orientation of the liquid crystal was observed by a change in the amount of transmitted light under a polarizing microscope. FIG. 1 shows a change in the amount of transmission with respect to the applied electric field (MV / m) when the amount of transmitted light in the state where no electric field is applied is 100%. In addition,
For comparison, the change in the amount of transmitted light of the liquid crystal composition A was measured in the same manner at room temperature, and the results are shown in FIG.

As a result, it is found that the orientation of the smectic phase of the liquid crystal composition to which the compound of the present invention is added easily changes due to the change of the electric field.

[0041]

The compound of the present invention can be added to a ferroelectric liquid crystal composition in a small amount to increase the helical pitch of the SmC ^* phase and Ch phase without affecting other physical constants such as spontaneous polarization. The optically active substance of the present invention, when added to a smectic liquid crystal, significantly weakens the layer structure and easily induces a change in the orientation direction of the smectic phase by applying a weaker external field. The liquid crystal composition containing the liquid crystal composition has a remarkable effect, and the liquid crystal composition containing the liquid crystal composition has a remarkable effect that an optical element can be manufactured.

[Brief description of the drawings]

FIG. 1 is a view showing a change in transmission amount when an electric field (MV / m) is applied by injecting a liquid crystal composition into a cell in Example 3.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location C07C 205/42 9450-4H C07C 205/42 255/54 9357-4H 255/54 C07D 239/26 C07D 239/26 C09K 19/20 C09K 19/20 19/34 19/34 G02F 1/13 500 G02F 1/13 500 // C07M 7:00

Claims (8)

[Claims] [Claim 1] The following general formula (1) (Wherein A and B each represent a hard group, and R ₁ and R ₂ each represent a soft group). 2. An optically active 2-methylsuccinic acid diester compound according to claim 1, wherein the compound has an asymmetric center on the methine carbon to which the carbonyl group and the methyl group are bonded. 3. An optically active form of the 2-methylsuccinic acid diester compound according to claim 2,
A liquid crystal composition characterized by being added to a ferroelectric liquid crystal material exhibiting a cholesteric phase or a chiral smectic C phase. 4. An optically active form of the 2-methylsuccinic acid diester compound according to claim 2,
4-cyano-4'-alkylbiphenyl or 4-cyano-
A liquid crystal composition characterized by being blended with a liquid crystal material exhibiting a smectic phase containing 4'-alkoxybiphenyl. 5. The following general formula (2): 3. The optically active form of the 2-methylsuccinic acid diester compound according to claim 2, wherein m is an integer of 1 to 18, and C ^* represents an asymmetric carbon to which optical activity has been imparted. 6. The following general formula (3): (Wherein m represents an integer of 1 to 18), wherein 5-alkyl-2- (4-hydroxyphenyl) pyrimidine and optically active 2-methylsuccinic acid are esterified. Item 6. The method for producing a 2-methylsuccinic acid diester compound according to Item 5. 7. The following general formula (4): 3. The optically active form of the 2-methylsuccinic acid diester compound according to claim 2, wherein X is a cyano group, a nitro group, fluorine or chlorine. 8. The following general formula (5): 8. The method according to claim 7, wherein 4-hydroxybiphenyls represented by the formula (X represents a cyano group, a nitro group, fluorine or chlorine) are esterified with optically active 2-methylsuccinic acid. The method for producing a 2-methylsuccinic acid diester compound of the above.