JPS6246A - Liquid crystal - Google Patents

Abstract

NEW MATERIAL:A compound shown by the formula (R1 is 1-18C alkyl; R2 is alkyl, halogenated alkyl, aralkyl or halogenated aralkyl; when m is 0, X is single bond and when m is 1 or 2, X is single bond, -O-, -COO- or -OCO-). EXAMPLE:( S, S )-1-Chloro-2-methylbutylcarboxylic acid-4'-(4''-heptylcarbonyloxy phenyl)phenyl ester. USE:A liquid crystal substance showing ferroelectricity, capable of lowering a ferroelectric liquid crystal temperature range of a substance which, does not become a ferroelectric liquid crystal by itself without damaging its ferroelectricity, by blending the substance with this liquid crystal substance. PREPARATION:For example, a 4-(4'-alkylcarbonyloxyphenyl)phenol is condensed through dehydration with a carboxylic acid such as an alkylcarboxylic acid, etc., in an inert solvent by the use of a condensation agent to give a compound shown by the formula.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel liquid crystal substance, a liquid crystal composition containing the liquid crystal substance, and an optical switching device using the liquid crystal composition containing the liquid crystal substance.

Furthermore, in this specification, the term "liquid crystalline substance" refers to a substance that is useful as a component of a liquid crystal composition even if it is not detected to exhibit a liquid crystal phase by itself.

BACKGROUND OF THE INVENTION Display systems for liquid crystal display devices that are currently in widespread use are twisted nematic type (TN type) and dynamic scattering type (DS type). These are nematic liquid crystals,
There is a display using a nematic liquid crystal cell as the main component. One of the disadvantages of conventional nematic liquid crystal cells is the fact that the response speed is slow, and a response speed of only a few m5ec can be obtained at most. This is one of the factors that limits the range of applications of nematic liquid crystal cells. However, it has recently been found that a faster response can be obtained by using a smectic liquid crystal cell.

It has become clear that some optically active smectic liquid crystals exhibit ferroelectricity, and there are great expectations for their use. Liquid crystals exhibiting ferroelectric properties, ie ferroelectric liquid crystals, were developed in 1975 by R.B.
It is a compound synthesized by Meyer et al. and whose representative example is 4-(4-n-decyloxybenzylideneamino)cinnamic acid-2-methylbutyl ester (hereinafter abbreviated as DOBAMBC). Tsuku C
It is characterized by exhibiting ferroelectricity in the phase (hereinafter abbreviated as SmC* phase) (J, Phys.
1que, 3rd edition, L-69 (1975)).

In recent years, N, A, C1ark et al. (Appl, Phys, L
et t, Yutama, 89 (1980)),
With the discovery of high-speed response on the μsec order in DOBAMBC's thin film cells, ferroelectric liquid crystals have been used not only for displays such as LCD televisions, but also for optical printer heads, by utilizing their high-speed response. It is attracting attention as a material that can be used for optoelectronic-related elements such as optical Fourier transform elements and light valves.

Problems to be Solved by the Invention However, since DOBAMBC has small spontaneous polarization and is a ship base, its physical and chemical stability is poor. Therefore, as a ferroelectric liquid crystal material, there is a strong desire for a compound that is physically and chemically stable, has a large spontaneous polarization, and has a high dielectric constant that can be driven at a low voltage.

Means for Solving the Problems In order to improve the above-mentioned drawbacks, the present inventors searched for various liquid crystal materials and arrived at the present invention.

That is, the present invention provides general formula (I) R1-COO-0-0-OCO-(0)m-X-R2,
(I) (However, in the above formula, R1 has 1 to 18 carbon atoms.
The alkyl group, R2 represents an alkyl group, a halogenated alkyl group, an aralkyl group, a halogenated aralkyl group,
X represents a single bond when m=o, and m=1 or 2
in the case of a single bond, -0-, -coo-, or -oco
- indicates. ) and liquid crystal compositions containing the same.

The compound of formula (I) is synthesized as follows.

4-(4'-Alkylcarbonyloxyphenyl)phenol and alkylcarboxylic acid, halogenated alkylcarboxylic acid, 4-alkylbenzoic acid, 4-alkoxybenzoic acid, 4-alkylcarbonyloxybenzoic acid, 4-alkyloxycarbonyl Benzoic acid, 4'-alkyl-4-biphenylcarboxylic acid, 4'-alkoxy-4-
Biphenylcarboxylic acid, 4'-alkylcarbonyloxy-4-biphenylcarboxylic acid, 4'-alkyloxycarbonyl-4-biphenylcarboxylic acid, halogenated aralkylcarboxylic acid, 4-halogenated alkylbenzoic acid, 4-halogenated alkylcarbonyl oxybenzoic acid,
4-halogenated alkyloxycarbonylbenzoic acid, 4
'-halogenated alkyl-4-biphenylcarboxylic acid,
4'-halogenated alkylcarbonyloxy-4-biphenylcarboxylic acid, 4'-halogenated alkyloxycarbonyl-4-biphenylcarboxylic acid, 4-aralkylbenzoic acid, 4-aralkylcarbonyloxybenzoic acid,
4-aralkyloxycarbonylbenzoic acid, 4'-aralkyl-4-biphenylcarboxylic acid, 42-aralkylcarbonyloxy-4-biphenylcarboxylic acid, 4'-
Aralkyloxycarbonyl-4-biphenylcarboxylic acid, 4'-aralkyloxycarbonyl-4-biphenylcarboxylic acid, 4-halogenated aralkyl benezoic acid, 4
-halogenated aralkylcarbonyloxybenzoic acid, 4
-halogenated aralkyloxycarbonylbenzoic acid, 4
'-halogenated aralkyl-4-biphenylcarboxylic acid, 4''-halogenated aralkylcarbonyloxy-4-
Biphenylcarboxylic acid and 4'-halogenated aralkyloxycarbonyl-4-biphenylcarboxylic acid are dehydrated and condensed in an inert solvent such as carbon tetrachloride using a condensing agent such as dicyclohexylcarbodiimide to obtain the desired product.

In addition, acid chlorides of carboxylic acids and 4-(
4°-Alkylcarbonyloxyphenyl)phenol may be reacted in a basic solvent such as pyridine.

In the above general formula (1), those in which the group represented by -X-R2 is optically active are particularly useful because they become ferroelectric liquid crystals. Here, the optically active group is easily derived from, for example, the following optically active alcohols and optically active carboxylic acids.

2-methylbutanol, 3-methylpentanol, 4-
Methylhexanol, 2-buta,nol, 2-pentanol, 2-hexanol, 2-8, butanol, 3-
Hexanol, 2-octanol, 1-phenylethanol, p-(2-methylbutyl)phenol, p-(2
-methylbutoxy)phenol, linalool, nerolidol, soarerol, carbomenthol, menthol,
Isomenthol, borneol, isoborneol, carveol, cholesterol, 2-halo 2-phenylethanol, 2-phenyl-3-halo 1-propanol, 3-phenyl-2-halo 1-propanol, 1-
Phenyl-2-halo 1-propertool, 3-halo 2
-Methyl-1-propatol, 1,1.1-)limulo 2-propatol, 2-halo-1-butanol, 3-halo-1-butanol, 2,3-dihalo-1-butanol, 2゜4-dihalo -1-butanol, 3,4-dihalo-
1-butanol, 1,1.1-) dahalo 2-butanol, 4,4.4-) rimuro 3-halo 1-butanol, 2,3.4-) rimuro 1-butanol, 3. ．． 3,
4,4.4-pentahalo 2-phtanol, 2-halo 3-methyl-1-butanol, 2-halo 3,3-dimethyl-1-butanol, 2-halo 1-pentanol,
3-halo-1-pentanol, 4-halo-1-pentanol, 2.4-dihalo-1-pentanol, 2.5-dihalo-1-pentanol, 1.1.1-) Rimulow 2-
Pentanol, 1,1,1.2.2-pentahalo 3-
Pentanol, 2-halo 3-methyl-1-pentanol, 2-halo 4-methyl-1-pentanol, 2-halo 3-monohalomethyl-4-methyl-1-pentanol, 2-halo 1' J\xanol, 3-Hello 1
-hexanol, 4-halo-1-hexanol, 5-halo-1-hexanol, 2,5-dihalo-1-hexanol, 2.6-cyhalo-1-hexanol, 1,1.1
-Trihalo 2-hexanol, 2,5.6-trihalo 1-hexanol, 2-hero l-heptatool, 1
, 1.1-) Rimlow 2-Heptatool, 2-Harrow 1
-Octatool, L 1. i-Trihalo 2-octatool, 2-halo 2-phenylethanoic acid, 3-halo 2-methylpropanoic acid, 2-phenyl-3-halopropanoic acid, 3-phenyl-2-methylpropanoic acid, 2-phenyl- 3-halopropanoic acid, 2-halobutanoic acid, 3-halobutanoic acid, 2,3-dihalobutanoic acid, 2,4-dihalobutanoic acid, 3,4-dihalobutanoic acid, 4°4.4-) dahalo-3-halobutanoic acid, 2,3゜4-trihalobutanoic acid, 2-halo 3-methylbutanoic acid, 2-halo 3,3
-dimethylbutanoic acid, 2-halopentanoic acid, 3-halopentanoic acid, 4-halopentanoic acid, 2,4-dihalopenconic acid, 2゜5-dihalopentanoic acid, 2-halo-3-methylpentanoic acid, 2-halo-4-methyl Pentanoic acid, 2-
Halo 3-monohalomethyl-4-methylpentanoic acid, 2
-halohexanoic acid, 3-halohexanoic acid, 4-halohexanoic acid, 5-halohexanoic acid, 2゜6-cyhalohexanoic acid, 2,6-cyhalohexanoic acid, 2,5.6-)lihalohexanoic acid, 2-halohexanoic acid, 2-Herooctanoic acid, 2-phenylpropanoic acid, 2-phenylbutanoic acid, 3
-Phenyl-2-methylpropanoic acid, 2-methylbutanoic acid, 2,3-dimethylbutanoic acid, 2,3-dimethylbutanoic acid, 2,3,3-trimethylbutanoic acid, 2-methylpentanoic acid, 3-methylpentane acid, 2゜3-dimethylpentanoic acid, 2,4-dimethylpentanoic acid, 2,3,3.
4-tetramethylpentanoic acid, 2-methylhexanoic acid,
3-methylhexanoic acid, 4-methylhexanoic acid, 2,5
-dimethylpentanoic acid, 2-methylhebutanoic acid, 2-methyloctanoic acid, 2-triheromethylpentanoic acid, 2-
Trihalomethylhexanoic acid, 2-trihalomethylhebutanoic acid, etc.

(However, 8 days in the above chemical formula represents chlorine, bromine, or iodine.) Some of the above optically active alcohols can be easily reduced by asymmetric reduction of the corresponding ketone with an asymmetric metal catalyst, microorganism, or enzyme. can get. Others can be derived from optically active amino acids and optically active oxyacids, such as those naturally occurring or obtained by resolution.

Furthermore, some of the above-mentioned optically active carboxylic acids can be obtained by oxidation of the corresponding alcohol and reductive deamination of the amino acid. Others are naturally occurring or can be derived from optically active amino acids and optically active oxyacids, such as the following, which are either naturally occurring or increased by resolution.

Alanine, valine, leucine, isoleucine, phenylalanine, serine, threonine, allothreonine, homoserine, alloisoleucine, tert-leucine, 2-
Aminobutyric acid, norvaline, norleucine, ornithine,
Lysine, hydroxylysine, phenylglycine, trifluoroalanine, aspartic acid, glutamic acid, lactic acid, mandelic acid, tropic acid, 3-hydroxybutyric acid, malic acid, tartaric acid, isopropylmalic acid, etc.

Effect The compounds of the present invention exhibit ferroelectric properties. Further, by mixing a substance that does not form a ferroelectric liquid crystal by itself with the above-mentioned ferroelectric liquid crystal substance, the temperature range of the ferroelectric liquid crystal can be lowered without impairing its ferroelectricity.

The compounds of the present invention may be used alone or in combination of two or more. By mixing, the temperature range of the ferroelectric liquid crystal can be expanded without impairing its ferroelectric properties.

Among the compounds of the present invention, optically active compounds may be added to nematic liquid crystals for purposes such as white tiller type color display, cholesteric nematic phase transition type display, and prevention of reverse domain generation in TN type cells. It is possible.

Further, since the compound of the present invention becomes a smectic liquid crystal, it can also be used for memory type display elements such as thermal writing laser writing.

Effects of the Invention The compounds of the present invention are chemically stable, have extremely large spontaneous polarization, and exhibit enantio-1-ropic properties. Compounds of the invention include, for example, D.

Unlike BAMBC, DOB does not have a Schiff base.
It is much more stable than AMB C. Furthermore, this compound has extremely large spontaneous polarization and exhibits enantiotropic properties. For example, (S,S)-1-chloro-2-methylbutylcarbon M-th'-(41"
-hebutylcarbonyloxyphenyl)-phenyl ester has a spontaneous polarization of 210 nC/ctti''.Furthermore, the temperature range in which it exhibits ferroelectricity is 70°C to 50'C, and it exhibits good enantiotropic properties.

In addition, in order to be used in liquid crystal displays, etc., it is necessary to exhibit ferroelectricity in a temperature range higher than the room temperature range, and this invention shows that such liquid crystal compositions can be obtained by using the compounds of the invention. be able to.

For example, (S)-4-(1'-methylpropylcarbonyloxy)benzoic acid-4"-(4'"'-octylcarbonyloxyphenyl)phenyl ester and (S,5)
-1-chloro-2-methylbutylcarboxylic acid-4'-(
A liquid crystal composition containing 27% by weight and 3% by weight of 4''-hebutylcarbonyloxyphenyl) phenyl ester exhibits ferroelectricity up to 89°C.

EXAMPLES The compounds of the present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples. Further, the phase transition temperature described below may vary somewhat depending on the purity of the compound.

Example 1 (S,5)-1-chloro-2-methylbutylcarboxylic acid
Synthesis and physical properties of -4'-(4''-hebutylcarbonyloxyphenyl)phenyl ester C7H15-Coo
-0-(X) -0CO-CH(CI)-CH(C)
! 3) -C2H5 Zero 4. Dissolve 40 g of 4'-biphenol in 300 ml of lysine and add 1 part of hebutylcarboxylic acid chloride while stirring.
Drop 9ml. After heating for 1 hour, water was added and the precipitated crystals were filtered out, followed by Soxhlet extraction with toluene to give 4-(4'-hebutylcarbonyloxyphenyl).
A crude product of phenol is obtained. If necessary, this is purified using a silica gel column.

8 g of 4-(4'-hebutylcarbonyloxydiphenyl)phenol and 6.2 g of dicyclohexylcarbodiimide
g, (S,5)-1-chloro[:]-]2-methylbutylcarboxylic acid 4.5 and 4-pyrrolidinopyridine were dissolved in 500 ml of carbon tetrachloride and allowed to stand for 6 hours. The precipitated crystals are filtered, concentrated, and purified using a silica gel column (chloroform is used as a developing solvent).

The IR spectrum of the compound is shown in FIG. Further, the phase transition point of the compound upon cooling is shown in Table 1.

A polyethylene terephthalate film with a thickness of 25 μm was used as a spacer, and a cell made of Nesa glass (S, 5
)-1-chloro-2-methylbutylcarboxylic acid-4'
-(4''-J\butylcarbonyloxyphenyl)phenyl ester was encapsulated, an alternating current of 100 Hz was applied, and the dielectric constant was measured by the bridge method. The results are shown in FIG.

Furthermore, when we measured the spontaneous polarization using the same cell using the Soyer-Tower method, we found that it was 210 nC/c-
It was very thick.

The phase transition point of this compound is shown in Table 1.

Example 2 Synthesis and physical properties of (S)-4-(1'-methylpropylcarbonyloxy)benzoic acid-4"-(4"9-octylcarbonyloxyphenyl)phenyl ester CaH17-COO-0-Oo -0CO- 0-OCO
-C)l(CH3)-C2H5 7g of 4-hydroxybenzoic acid is dissolved in 40ml of pyridine, and 7.2g of (S)-2-methylbutanoic acid is added dropwise. After stirring for a while, add hydrochloric acid to make it acidic. Extract with 100 ml of chloroform and concentrate 5)-4-
(1'-Methylpropylcarbonyloxy)benzoic acid is obtained.

1.1 g of (S)-4-(1'-methylpropylcarbonyloxy)benzoic acid was mixed with 10 ml of thionyl chloride and 50 ml of carbon tetrachloride, refluxed for 1 hour, concentrated, and mixed with 50 ml of carbon tetrachloride, 10 ml of pyridine, and 4- Add 1.6 g of (4'-octylcarbonyloxyphenyl)phenol and stir for a while.

After filtering out the precipitated crystals, the crystals were concentrated and transferred to a silica gel column (
Chloroform is used as a developing solvent.

The desired product is obtained by purification.

Example 3 The phase transition points of representative compounds of the present invention synthesized in the same manner as in Example 1 are summarized in Table 1.

Example 4 A liquid crystal composition having the following composition was prepared using the compound of the present invention.

C+oH+-Coo-0-()-0CO-CH(C1
”)-CHCCI(a>-C2H5* 49% by weight C5H17-0-0-0-OCO-CH(CI)-C)
1(C)+3)-C2)15 Zerone 51% by weight The phase transition temperature of this composition was as follows.

CSX Sl* scl: SA
1・ 18・ 22・ 33・ 57・
68・Also, its spontaneous polarization is 2070C/CT at 33℃
It was “I+”.

Example 5 A liquid crystal composition having the following composition was prepared using the compound of the present invention.

C6Hl3-COO-()-■-0CO-C)1(CI
)-CH(C)13)-C2H5 Nene 4.9% by weight C7H+5-C00-■-0-OCO-CH(CI)-
CH(C113)-C2H5* *4.9% by weight C3)117-COO-() -<E)-0CO-C)
+(CI)-CH(CH3)-C2)+5ne
*5.6% by weight C9Hu-COO-0-(E)-0CO-CH(CI>
-C)I(C)13)-C2H5*
*5.9% by weight CIoH2+-C00-()-C)-0CO-C)I(
CI)-Ct((CH3)-C2Hsnene469% by weight Ca1n-COO-0-■-0'C0-C)1(C1)
-C)I(C)13)2 8.4% by weight C9)In-COO-(ii>-〇-0CO-CH(C
I)-CH(C)13)2 8.4% by weight Cl01121-COO-Oo-00-0CO-C)l
(C1)-C)I(CH3)2 7.7% by weight C5Hu-0-0-0-OCO-C)I(CI)-CM
(CH3)-C2H5nene9, 1! i Amount % C9Hn-0-0-■-0CO-C)1(C1)-C)
l(C)13)-C2H5 Nene 9.8% by weight C3HI? -0-()-C00-O-0-CH2-CH
(CH3)-C2115Ne30.7% by weight This composition exhibits an SC* phase from room temperature to 49°C,
Its spontaneous polarization was 150 nC/cvr+' at 22°C, which was highly practical.

This composition was sealed in a cell made of Nesa glass using a 10μ thick polyethylene terephthalate film as a spacer, placed between two orthogonal polarizers, and heated at 20 V.
A pp rectangular wave was applied and the electro-optic effect was observed.

In addition to very clear contrast, a quick response was visible, proving that it can be applied to optical switching devices.

The time required for the transmitted light to change from 10% to 90% was 300 μsec at 26° C., which was very fast.

Example 6 A liquid crystal composition having the following composition was prepared using the compound of the present invention.

C5f19-COO-Oa -Oo -0CO-CH(
CI)-C)I(C)Ia)-C2t15ne*73% by weight C3)In-Coo-<1i)-■-0CO-0-OC
O-CH(CH3)-C2H5* 27% by weight This composition exhibits an SC* phase from room temperature to 89°C,
It was highly practical.

[Brief explanation of drawings]

Figure 1 shows the (S,S)-1-chloro-2- obtained in Example 1.
The infrared absorption spectrum of methylbutylcarboxylic acid-4'-(4"-heptylcarbonyloxyphenyl)phenyl ester is shown. Figure 2 shows the infrared absorption spectrum of (S,5)-1-chloro-2-methylbutylcarboxylic acid-4"-( 4 is a drawing showing the relationship between the dielectric constant and temperature measured for 4'-hebutylcarbonyloxyphenyl) phenyl ester.

Claims (15)

[Claims] (1) General formula (I) ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) (However, in the above formula, R1 is an alkyl group having 1 to 18 carbon atoms, R2 is an alkyl group, a halogenated alkyl group, etc.) group, aralkyl group, halogenated aralkyl group, and X is m
=0 indicates a single bond, and m=1 or 2 indicates a single bond, -O-, -COO-, or -OCO-. ). (2) General formula (II) ▲Mathematical formulas, chemical formulas, tables, etc.▼(II) (However, in the above formula, R1 is an alkyl group having 1 to 18 carbon atoms, and R3 is an alkyl group or an aralkyl group. and X
is a single bond when m=0, -O-CH2-, -COO-CH2-, or -OC when m=1 or 2
O- is indicated, and * indicates an optically active carbon atom. ). (3) General formula (III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (III) (However, in the above formula, R1 is an alkyl group having 1 to 18 carbon atoms, and R4 is 1-methyl-ethyl represents a group, and X is
In the case of m=0, a single bond; in the case of m=1 or 2,
-O-CH2-, -COO-CH2-, or -OCO-
and * indicates an optically active carbon atom. ) The compound according to claim (1) (4) General formula (IV) ▲Mathematical formulas, chemical formulas, tables, etc.▼(IV) (However, in the above formula, R1 is an alkyl group having 1 to 18 carbon atoms, and R5 is 2-methyl-propyl. represents a group, and X is a single bond when m=0, and -O-CH2-, -COO-CH2-, or -OCO when m=1 or 2.
- and * indicates an optically active carbon atom. ) The compound according to claim (1) (5) General formula (V) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (V) (However, in the above formula, R1 represents an alkyl group having 1 to 18 carbon atoms, R6 represents an ethyl group, X is a single bond when m=0, and -O-CH2 when m=1 or 2
-, -COO-CH2-, or -OCO-, and * indicates an optically active carbon atom. ) The compound according to claim (1) (6) General formula (VI) ▲Mathematical formulas, chemical formulas, tables, etc.▼(VI) (However, in the above formula, R1 represents an alkyl group having 1 to 18 carbon atoms, and X represents m=0 In the case of single bond, m=1
, or in the case of 2, -CH2-, -O-CH2-, -
It represents COO-CH2- or -OCO-, and * represents an optically active carbon atom. ) Claims (
Compounds described in section 1) (7) General formula (VII) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (VII) (However, in the above formula, R1 represents an alkyl group having 1 to 18 carbon atoms, and X represents m=0 In the case of single bond, m=1
, or in the case of 2, -CH2-, -O-CH2-, -
It represents COO-CH2- or -OCO-, and * represents an optically active carbon atom. ) Claims (
Compounds described in section 1) (8) General formula (VIII) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (VIII) (However, in the above formula, R1 represents an alkyl group having 1 to 18 carbon atoms, R6 represents a methyl group, X is a single bond when m=0, and -O-CH2 when m=1 or 2
-, -COO-CH2-, or -OCO-, and * indicates an optically active carbon atom. ) The compound according to claim (1) (9) General formula (IX) ▲Mathematical formulas, chemical formulas, tables, etc.▼(IX) (However, in the above formula, R1 represents an alkyl group having 1 to 18 carbon atoms, R7 represents an ethyl group, X is a single bond when m=0, and -O-CH2 when m=1 or 2
-, -COO-CH2-, or -OCO-, and * indicates an optically active carbon atom. ) The compound according to claim (1) (10) General formula (X) ▲Mathematical formulas, chemical formulas, tables, etc.▼(X) (However, in the above formula, R1 represents an alkyl group having 1 to 18 carbon atoms, R8 represents a propyl group, X is a single bond when m=0, and -O-CH when m=1 or 2
2-, -COO-CH2-, or -OCO-, *
indicates an optically active carbon atom. ) The compound according to claim (1) (11) General formula (X I) ▲Mathematical formulas, chemical formulas, tables, etc.▼(X I) (However, in the above formula, R1 is an alkyl group having 1 to 18 carbon atoms, and R9 is a butyl group. and X is a single bond when m=0, and -O-CH2 when m=1 or 2
-, -COO-CH2-, or -OCO-, and * indicates an optically active carbon atom. ) The compound according to claim (1) (12) General formula (XII) ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (XII) (However, in the above formula, R1 represents an alkyl group having 1 to 18 carbon atoms, R10 represents a benzyl group, X is a single bond when m=0, and -O-C when m=1 or 2
represents H2-, -COO-CH2-, or -OCO-,
* indicates an optically active carbon atom. ) The compound according to claim (1) (13) General formula (XIII) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (XIII) (However, in the above formula, R1 represents an alkyl group having 1 to 18 carbon atoms, and X represents m=0 In the case of single bond, m=1
, or in the case of 2, -CH2-, -O-CH2-, -
It represents COO-CH2- or -OCO-, and * represents an optically active carbon atom. ) Claims (
Compounds described in section 1) (14) General formula (I) ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) (However, in the above formula, R1 is an alkyl group having 1 to 18 carbon atoms, R2 is an alkyl group, a halogenated alkyl group, etc.) group, aralkyl group, halogenated aralkyl group, and X is m
=0 indicates a single bond, and m=1 or 2 indicates a single bond, -O-, -COO-, or -OCO-. ) A liquid crystal characterized by containing at least one compound represented by (15) General formula (I) ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) (However, in the above formula, R1 is an alkyl group having 1 to 18 carbon atoms, R2 is an alkyl group, a halogenated alkyl group, etc.) group, aralkyl group, halogenated aralkyl group, and X is m
=0 indicates a single bond, and m=1 or 2 indicates a single bond, -O-, -COO-, or -OCO-. ) An optical switching element using a liquid crystal containing at least one compound represented by: