JPH0794435B2 - Optically active lactam compound and liquid crystal composition using the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to an optically active lactam compound used in a display device or an electro-optical device, and a ferroelectric smectic liquid crystal composition using the same.

[Prior Art] A liquid crystal display element using a nematic liquid crystal conventionally used for a display unit of a watch calculator or the like has a response speed which is much slower than that of another display element, for example, a light emitting diode. Applications in areas where response is required, such as optical communication and liquid crystal display devices for printer heads, have been limited.

Recently, a liquid crystal display device using a smectic liquid crystal exhibiting ferroelectricity has been reported as a liquid crystal display device exhibiting high-speed response (for example, NAClark, STLagerwall, Appl.Phys.
Lett. 36 , 899 (1980)) is attracting attention.

Ferroelectric smectic liquid crystals include a chiral scmetic C phase and a chiral smectic H phase.
These show a layered structure in which the liquid crystal molecules are tilted rather than perpendicular to the stacking direction of the layers. This tilting direction is
The liquid crystal molecules are arranged so as to form a helix with respect to the stacking direction of the layers, and spontaneous polarization occurs in a direction parallel to this layer and perpendicular to the liquid crystal molecules, and exhibits ferroelectricity. This helical structure is considered to be the cause of the ferroelectricity. A material exhibiting ferroelectricity exhibits responsiveness as a ferroelectric substance to an electric field, and reorients by inverting the direction of spontaneous polarization according to the direction of the electric field.

At this time, it is known that the response becomes faster when the spontaneous polarization is large and the viscosity is low, for the same electric field strength. In addition, an element using a ferroelectric smectic liquid crystal has a memory property, and researches using this memory for high density display have been actively conducted.

[Problems to be Solved by the Invention] As a ferroelectric smectic liquid crystal, conventionally, many compounds of a Schiff base type as shown below have been studied.

p-decyloxybenzylidene-p'-amino-2-methylbutyl-cinnamic acid ester (DOBAMBC).

However, since such a Schiff base type compound is easily hydrolyzed, there is a problem that it is easily decomposed by water.

Further, as an ester type compound exhibiting a chiral smectic C phase, a compound represented by the following general formula (II) has been known.

(GW Gray, etc.Mol.Cryst.Liq.Cryst., 1976, 37 189, 211) (R is a straight-chain alkyl group having 5 to 10 carbon atoms) However, this ester compound has a problem that its spontaneous polarization value is small although it withstands moisture.

More recently, as a compound with large spontaneous polarization, DOBA-1
-The compound of the following structure abbreviated as MBC is Yoshino et al. (K.YOS
HINO et al., JJAP, 1984, 23 L 175-177).

However, since this compound is also a Schiff base type, it has a drawback that it is easily decomposed by water.

[Means for Solving the Problem] The present invention has been made to solve the above-mentioned problems, and is an optical active material used for forming a stable and fast-responsive ferroelectric smectic liquid crystal composition. A lactam compound and a ferroelectric smectic liquid crystal composition for providing a general formula, (Wherein, Z is -COO -, - OCO -, - CH 2 CH 2 -, - OCH 2 -
Or -CH ₂ O-a represents, Z 'represents a single bond, -COO -, - OCO
Represents —, —CH ₂ CH ₂ —, —OCH ₂ — or —CH ₂ O—, R represents an alkyl group or alkoxy group having 1 to 12 carbon atoms, a cyano group or a halogen atom, and R ′ represents 1 carbon atom. To 12 alkyl groups, ring A and ring B represent 1,4-di-substituted phenylene or trans-1,4-di-substituted cyclohexylene, n represents 0 or 1, and * represents an optically active center. Represent ) Is an optically active lactam compound, and is a ferroelectric smectic liquid crystal composition containing at least one compound.

The general name of the compound of the general formula (I) of the present invention is (3R)
-Or a derivative of (3S) -2,3-dihydro-2-alkyl-3-methyl-1H-isoindol-1-one.

In the general formula (I), Z is -COO -, - OCO -, - CH 2 C
H ₂ −, —OCH ₂ — or —CH ₂ O—, Z ′ is a single bond,
COO -, - OCO -, - CH 2 CH 2 -, - OCH 2 - or represents a -CH ₂ O-, generally Z 'is when a single bond is a low viscosity, Z and / or Z' is -COO-,
Since the maximum temperature (Ts) indicating the smectic C phase is high, Z
Is preferably —COO—, and Z ′ is preferably a single bond or —COO—.

Further, in the case of n = 1, if both Z and Z ′ are —COO—, the viscosity becomes high. In that case, therefore, Z ′ is preferably a single bond.

Ring A and ring B represent trans-1,4-di-substituted cyclohexylene or 1,4-di-substituted phenylene, but since trans-1,4-di-substituted cyclohexylene generally has a lower Ts, n = 1 In this case, at least one of ring A and ring B is preferably 1,4-disubstituted phenylene, and n
When = 0, ring A is preferably 1,4-disubstituted phenylene.

R represents an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a cyano group or a halogen atom. In the case of a cyano group, the viscosity is high, and in the case of a halogen atom, Ts is Since it is low, it is preferably an alkyl group or an alkoxyl group. Further, in the case of an alkyl group or an alkoxyl group, when the carbon number is small, the melting point is high, and when it is too large, the viscosity is high.
However, 2 to 8 is preferable. Further, R may be linear or branched, but linear ones are generally preferable because the smectic liquid crystal upper limit temperature is higher when mixed with another compound exhibiting liquid crystallinity.

R'is an alkyl group having 1 to 12 carbon atoms, and is 1 to 12 and preferably 2 to 8 because the viscosity is high in the case of R and when the number thereof is too large.

The optical rotatory power of the compound represented by formula (I) may be levorotatory or dextrorotatory.

The compound represented by the general formula (I) is used for a ferroelectric smectic liquid crystal display device or an electro-optical device, so that it has another chiral smectic C phase in a desired temperature range. Alternatively, it is appropriately mixed with a smectic liquid crystal or an optically active substance and used as a ferroelectric smectic liquid crystal composition. Further, nematic liquid crystal, non-liquid crystal, dichroic dye or the like may be added for adjusting the spiral pitch or for displaying color. When the content of the compound represented by the general formula (I) in the ferroelectric smectic liquid crystal composition of the present invention is too large, the ferroelectric smectic maximum temperature tends to be lowered, and when it is too small. Has a small effect of increasing its spontaneous polarization, it is set to 1 to 90 Wt%, preferably 2 to 50 Wt.
Wt% is good.

Examples of the counterpart compound used as a ferroelectric smectic liquid crystal composition by mixing with the compound of the general formula (I) of the present invention include the following.

In the following examples, R ^* represents an optically active alkyl group or alkoxy group, R has no relation to R of the present invention, and represents a linear or branched alkyl group or alkoxy group, which is identical to one compound. , R ^* and R are not necessarily the same groups.

In addition to these, various known liquid crystal or non-liquid crystal liquid crystal additives can be used in combination, and examples thereof include the following.

And compounds obtained by substituting a part of hydrogen atoms of these benzene ring, cyclohexane ring and the like with halogen, cyano group, methyl group and the like.

Examples of this are compounds such as the following compounds having a negative dielectric anisotropy. In the following examples, R has nothing to do with R of the present invention and represents a linear or branched alkyl group having 1 to 12 carbon atoms, and even if the same R is shown in one compound, They are not necessarily the same groups.

Examples of the dichroic dye include dyes used in so-called guest-host type liquid crystal display devices such as trisazo type and anthraquinone type.

The ferroelectric liquid crystal display element or the electro-optical element is arranged so as to sandwich the liquid crystal phase, and at least one transparent substrate having electrodes on the whole surface or a part thereof is surrounded by the liquid crystal layer. And a seal member formed between the electrode substrates. In the liquid crystal display element, the thickness between the substrates is 0.
5 to 20 μm is preferable. Further, the substrates may be subjected to alignment control processing parallel to each of them. As a means for controlling the orientation, an orientation control film may be applied partially or entirely on the electrode substrate. As the orientation control film, a polymer material such as polyimide having a refractive index of 1.5 or more is preferable. Furthermore, at least one polarizer is preferably attached to the liquid crystal element. At least two electrode substrates are required, but a larger number of electrode substrates may be stacked and used.

The compound of the present invention in which Z is —COO— can be synthesized, for example, by the route shown below.

That is, a chlorinating agent such as thionyl chloride or phosphorus oxychloride is caused to act on a carboxylic acid to form an acid chloride, and an optically active lactam (2) having a phenolic hydroxyl group is added thereto in the presence of a basic substance such as pyridine. By reacting and performing a series of purification treatments such as extraction, recrystallization and column chromatography, a compound of formula (I) in which pure Z is —COO— can be synthesized.

The lactam (2) as a raw material is lithiated with an optically active N-alkyl-N-α-phenethylamine butyllithium and then reacted with carbon dioxide to nitrate, reduce, and diazotize the lactam obtained. It can be synthesized by

In addition, a compound in which Z is -OCO- can be synthesized, for example, by the route shown below.

(+)-2,3-Dihydro-3-methyl-2-substituted-1H-
After acetylating isoindol-1-one (3),
The haloform reaction is carried out, and (+)-2,3-dihydro-3-
Methyl-2-substituted-1H-isoindol-1-one-6
-The carboxylic acid (4) is converted to the acid chloride, and then reacted with the hydroxy compound (5) in the presence of a basic substance such as pyridine, and subjected to a kind of purification treatment such as extraction, recrystallization and column chromatography. Therefore, pure Z is -OCO
A compound of formula (I) -can be synthesized.

[Examples] Next, the present invention will be specifically described with reference to Examples.

Example 1 2.5 g (0.01 mol) of the compound (1) and 10 ml of thionyl chloride were charged in 50 ml of carbon tetrachloride and stirred at reflux temperature for 6 hours. After the solvent was distilled off with an evaporator, 30 ml of toluene was added, and 2.5 g (0.01 mol) of the compound of 1 and 2 ml of pyridine were added, and the mixture was stirred at room temperature for 6 hours. Pour the reaction mixture into 100 ml of water,
It was extracted with 100 ml of toluene for 3 hours. Toluene layer is water 100
After washing with ml, the extract was dried over anhydrous magnesium sulfate, and the solvent was distilled off with an evaporator. The remaining yellow solid was applied to a column of alumina with toluene as a solvent and recrystallized twice from hexane to obtain the target compound. Compound (4'-n-octyloxybenzoic acid- (3S)
-2,3-Dihydro-2-n-hexyl-3-methyl-1H
2.8 g (0.0058 mol) of -isoindol-6-yl ester) were obtained as colorless crystals. Yield 58%. Melting point 99.6 ° C.
The IR spectrum of this compound is shown in FIG.

The 1H NMR spectrum of this compound was as follows:

δ (ppm, CDCl ₃ solvent, TMS internal standard) 6.9-8.2 Aromatic 7H m 4.53 Ar-CH 2H q 7Hz 3.5-4.1 OCH ₂ , NCH 3H m 2.9-3.2 NCH 1H m 0.8-1.8 Aliphatic 26H m 1.35 Ar-C -CH ₃ 3H d 7Hz example 2-10 Except that the corresponding carboxylic acid is used instead of the compound of
By performing the same operation as in Example 1, R'is n-
The following compounds were obtained using the C ₈ H ₁₇ compound.

Example 11 The compound of acetylation is reacted with acetyl chloride in the presence of aluminum chloride in carbon disulfide, followed by haloform reaction with sodium hypobromite to give (+)-2,3-dihydro. -3-methyl-2
-N-hexyl-1H-isoindol-1-one-6-
A carboxylic acid was obtained. This carboxylic acid is reacted with thionyl chloride in carbon tetrachloride to give the acid chloride, and then 4-n
-Hexyl-4'-hydroxybiphenyl was reacted with toluene in the presence of pyridine. After the reaction, the reaction mixture was poured into water and extracted with toluene. The solvent was distilled off with an evaporator, and the remaining crude product was recrystallized from hexane to obtain the desired formula. Compound ((+)-2,3-dihydro-3-methyl-2-
n-Hexyl-1H-isoindol-1-one-6-carboxylic acid-4'-n-hexyl-4 "-biphenyl ester was obtained.

Example 12 The compound of Example 1 was treated with 4-n-octyloxybenzoic acid-
5.0 wt% was mixed with 4'-n-hexyloxyphenyl and the spontaneous polarization was measured. The measurement of the spontaneous polarization of the sample is 3μ
10m from the upper limit temperature (Ts) which shows smectic C phase by enclosing a spacer of m and enclosing in a cell with an electrode area of 1cm ^2.
Miyas applying 20Hz, 10V triangular wave at low temperature ℃
It was performed according to the method of ato et al. (K.Miyasatoet.al., JJA
P., 22, L661 (1983)) The magnitude of spontaneous polarization of this mixture was 1.25 nC / cm ² .
This size corresponds to the ferroelectric semen compound DO that has been studied in the past.
Considering that this mixture is the compound of Example 1 diluted to 5.0%, BAMBC is 3.7 nC / cm ² as a single product, which is extremely large. In addition, the mixture was changed from smectic C phase to smectic A at 62.4 ° C.
It transformed into a phase and further into an isotropic liquid phase at 85.8 ° C. 4-n-octyloxybenzoic acid-4'-n-
The maximum temperature of the smectic C phase of hexyloxyphenyl is
Since it is 65.0 ° C, it can be seen that the compound of the present invention can increase spontaneous polarization without significantly narrowing the temperature range of the smectic C phase, and is a very useful compound.

EFFECTS OF THE INVENTION The present invention provides an optically active lantam compound represented by the general formula (I) which has a large spontaneous polarization and does not narrow the temperature range of the smectic C phase, and a strong compound containing at least one compound. The provision of the inductive smectic liquid crystal composition has an excellent effect such that a display element or an electro-optical element capable of high-speed response over a wide temperature range can be formed.

[Brief description of drawings]

FIG. 1 is a compound and IR spectrum of Example 1 of the present invention.

Claims (3)

[Claims] 1. A general formula (Wherein, Z is -COO -, - OCO -, - CH 2 CH 2 -, - OCH 2 -
Or -CH ₂ O-a represents, Z 'represents a single bond, -COO -, - OCO
Represents —, —CH ₂ CH ₂ —, —OCH ₂ — or —CH ₂ O—, R represents an alkyl group or alkoxy group having 1 to 12 carbon atoms, a cyano group or a halogen atom, and R ′ represents 1 carbon atom. To 12 alkyl groups, ring A and ring B represent 1,4-di-substituted phenylene or trans-1,4-di-substituted cyclohexylene, n represents 0 or 1, and * represents an optically active center. Represent ) An optically active lactam compound represented by 2. The compound according to claim 1, wherein in the general formula (I), Z represents --COO--, ring A represents 1,4-disubstituted phenylene, and n represents 0. . 3. General formula (Wherein, Z is -COO -, - OCO -, - CH 2 CH 2 -, - OCH 2 -
Or -CH ₂ O-a represents, Z 'represents a single bond, -COO -, - OCO
Represents —, —CH ₂ CH ₂ —, —OCH ₂ — or —CH ₂ O—, R represents an alkyl group or alkoxy group having 1 to 12 carbon atoms, a cyano group or a halogen atom, and R ′ represents 1 carbon atom. To 12 alkyl groups, ring A and ring B represent 1,4-di-substituted phenylene or trans-1,4-di-substituted cyclohexylene, n represents 0 or 1, and * represents an optically active center. Represent ) A ferroelectric smectic liquid crystal composition containing at least one optically active lactam compound represented by the formula (1).