JPH01197459A - Optically active compound and liquid crystal composition - Google Patents

Abstract

NEW MATERIAL:An optically active compound shown by formula I (R1 is 1-18C alkyl; R2 is 4-18C alkyl, 4-alkylphenyl or 4-alkyloxyphenyl; C* is asymmetric carbon; l is 1 or 2; X is O, COO, OCO or single bond). EXAMPLE:Optically active 2-methyl-2-fluoromalonic acid ethyl-4'-hexyloxybiphenyl ester. USE:One component for liquid crystal composition. Being blended with a (optically active) smectic C liquid crystal having ester bond and useful as a display element having excellent chemical stability, light stability, large spontaneous polarization and high-speed response. PREPARATION:Fluoromalonic acid diester of racemic modification of a compound shown by formula IV is asymmetrically hydrolyzed to give an optically active fluoromalonic acid monoester shown by formula V, which is treated with a chlorinating agent such as oxalyl chloride into an acid chloride shown by formula VI, which is reacted with a hydroxy compound shown by formula VII in pyridine to give a compound shown by formula I.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a novel optically active compound and a liquid crystal composition having an optically active group.

"Prior Art" Currently, the display systems of liquid crystal display elements that are widely used in practical use are twisted nematic (TN) and dynamic scattering (DS). These are displays using nematic liquid crystal cells containing nematic type crystals as a main component. One of the disadvantages of conventional nematic liquid crystal cells is that their response speed is slow, with a maximum response speed on the order of several milliseconds.
Give me the facts. This is one of the factors that limits the range of applications for nematic liquid crystal cells. In contrast, it has recently become clear that a faster response can be obtained by using a smectic liquid crystal cell.

It is known that some optically active smectic liquid crystals exhibit ferroelectricity, and there is great interest in their applications. Ferroelectric liquid crystal was developed in 1975 by R.
, B., May-er et al. (Journard de Physique (J.
, P hys, ), 36. L69 (1975)), which is 4-(4°-n-dedyloxybenzylideneamino)-2-methylbutylcinnamate (DOB AMB
It is a Schiff base-based compound of which C) is a typical example, and is characterized by exhibiting ferroelectricity in an optically active state, that is, in a chiral smectic C phase.

After that, N, A, Clark (N, A, C1ark)
(Applied Physics Letters (A ppl,
Phys, I, ett, ), 36,899 (19
80)) discovered high-speed response on the microsecond order in DOBAMBC thin-film cells, and this led to the development of ferroelectric liquid crystals, which utilized their high-speed response and memory properties to create displays such as LCD televisions. It is attracting attention as a material that can be used not only for industrial purposes, but also for parts of optoelectronic devices such as printer heads, optical Fourier transform elements, and light valves. In ferroelectric liquid crystal cells, it is advantageous to use a material with a large dielectric constant (and a large spontaneous polarization) because the cell can be driven at high speed, so the development of a material with a large spontaneous polarization is desired.

In addition, for practical purposes, it is necessary that the liquid crystal composition itself be stable and exhibit ferroelectricity over a wide temperature range centered around room temperature.

[Problems to be solved by the invention] However, Schiff base-type compounds such as DOBAMBC have drawbacks in terms of stability against water and light, and the temperature range in which they exhibit ferroelectricity is about 50°C higher than room temperature. It was not suitable for practical use. Therefore, there are strong expectations for the realization of a material system that is physically and chemically stable and has large spontaneous polarization as a ferroelectric liquid crystal material.

An object of the present invention is to obtain a novel optically active compound and liquid crystal composition that are excellent in chemical stability and photostability and have large spontaneous polarization. Another object of the present invention is to provide a display element or the like having high-speed response using such a novel optically active compound or a liquid crystal composition containing the same.

"Means for Solving the Problems" To summarize the present invention, the first invention of the present invention relates to an optically active compound, which has the following general formula: (However, R1 is an alkyl group having 1 to 18 carbon atoms. and R
2 represents an alkyl group having 4 to 18 carbon atoms, a 4-alkylphenyl group, or a 4-alkyloxyphenyl group, and Q
represents 1 or 2, X is 10-1-COO-1-OC
O- or a single bond).

A second invention of the present invention relates to a liquid crystal composition, which comprises an optically active smectic C liquid crystal having an ester bond or a component consisting of a smectic C liquid crystal, and the general formula (1) of the first invention. It is characterized by containing the optically active compound represented by:

Among the compounds represented by the general formula (1), particularly preferred are the following general formulas <■>, (III) or C'V'
) is a compound represented by

......(II) (However, m represents an integer of 1 to !8, and n represents an integer of 4 to 18.) These optically active compounds have a fluorine and carbonyl group directly bonded to the asymmetric carbon c8. Therefore, it has high optical rotation. In addition, the central skeleton has a carboxybiphenyl, biphenylcarboxylic acid, or phenyl carboxybenzoate structure, and since there is a long-chain alkyl group at the end of the molecule, it itself exhibits liquid crystallinity, making it an optically active smectic C liquid crystal. When added, it does not reduce its liquid crystallinity.

On the other hand, the smectic C liquid crystal compound having an ester bond is not particularly limited, but for example, the following general formula (
One or more of the compounds represented by V) or (VI) can be used. In this case, either an optically active smectic C liquid crystal compound or a smectic C liquid crystal compound can be used.

C mountain. +, o QcooQ C00CHIC”1l(C
I+3)CtH8...(V) C mountain C"1l(CI+,) CI+(To3cOo○OC mountain n+1...(VI) (However, in the formula, n=an integer from 4 to 18 ) In the present invention, general formula (1), particularly (II), (■) or (
The amount of the optically active compound represented by tV) in the entire liquid crystal composition is not particularly limited, but is, for example, 1 to 30
It is preferable to set it as weight%.

If the amount of the optically active compound is less than the above, the problem arises that the spontaneous polarization value is too small and sufficient response cannot be obtained, and if the amount of the optically active compound is more than the above, the problem arises that the helix of the liquid crystal This is because the pitch becomes too small, which makes it difficult to manufacture the cell, and also causes the problem that the temperature range of the chiral smectic C phase becomes narrow.

The optically active compound in the present invention can be produced, for example, according to the following method in which intermediate compounds are sequentially used.

RIOCOCF(CHs)COO11→R,0COC”
F(CH,)COO11→R,0COC”F(CI+3
) COCQ (The optically active fluoromalonate monoester which is the phosphoric acid component is obtained by asymmetric hydrolysis reaction of racemic fluoromalonate diester. For details of this reaction, see, for example, The production of optically active ethyl hydrogen 2-methyl-2-fluoromalonate is described in the paper by Kitazume et al. Lipase etc. are used.

In addition, for the production of isomers in which the number of carbon atoms in the alkyl group R1 of the above compound differs, for example, hydrogen octyl 2-methyl-2-fluoromalonate, first the dioctyl form of the corresponding acid is prepared as reported by Ishikawa et al. (Nobuo Ishikawa). In addition, chemistry
Letters, 1981, p. 107),
It can then be produced by asymmetric hydrolysis in the same manner as diethyl 2-methyl-2-fluoromalonate.

Next, these optically active acid compounds are converted into acid chlorides using a chlorinating agent such as oxalyl chloride, and this is reacted with a hydroxy compound in pyridine to obtain the desired optically active compound.

"Example" Example 1 2.6 g of optically active hydrogen ethyl 2-methyl-2-fluoromalonate (this compound was produced by the method described in Kitazume et al.'s literature in FI) was chlorinated in methylene chloride. Kitazume et al.'s method of reacting with oxalyl 2.7mQ (T, Kitazume et al., Journal of
Organic Chemistry (J, Org, Chem,
), Vol. 51, p. 003 (1986)). This was dissolved in 25 ml of toluene, and 4-hexyloxy-4-hydroxybiphenyl 4.
6g was gradually added dropwise to a solution of 60mQ of pyridine to give a solution of 60~. The reaction was carried out at 70° C. for 5 hours, and the apparatus was kept overnight.

Water was added and extracted with toluene, washed with dilute aqueous sodium hydroxide solution and water, the toluene was distilled off, the residue was purified by silica gel column chromatography (solvent: butane-chloroform), and then recrystallized with petroleum ether. The optically active compound (1) is ethyl-4°-hexyloxybiphenyl 2-methyl-2-fluoromalonate 3.1
I got g.

Next, this compound (■) was sealed in a cell with a transparent electrode of approximately 3 μm thickness, and when observed with a polarizing microscope while applying an electric field of ±5 VS IHz, it clearly responded in the range of 54.6 to 58.5 °C. was recognized. Other phase transition temperatures are shown in Table 1. Note that SX represents chiral smectic C or other ferroelectric state, which at least partially responds to the above electric field. SA is smectic A state, N8+i chiral nematic phase, ■
represents an isotropic liquid crystal. Also, / indicates that the phase exists, and - indicates that it does not exist.

Further, when the spontaneous polarization of this compound was measured using the triangular wave method, the value was 43 nC/cm''.

(Left below) Table 1 Compound R+ Q X Re Cr'l
SX SA N” 1■ Cu1ls
2 0 Cs1lts ・54.6・58
．． 5.64.2 - ・■ 〃2 0 CJ,,
・60.7・67.4-69.3 - -■
〃20C,,l+,, ・57.2-62
．． 5-66.0 - ・■ 〃2 0 C,,)l
,, -56,0・67.4-69.2 - -
■ C,11,,20C,H,,・48.2・56.
1・62.6 − ・■ 〃2 − C, H,,・
55.3・63.8・75.4 −・■〃2
Coo C, 11,, 53.2, 57.6, 68.
5 - ・■〃2 Coo C? I1. s
・45.3・49.3・66.6 − ・■ 〃
2 COO-C,H,, -64,0-71,2-11
6,5-128,7-(ri ” 2 Coo
-OC1+1. ? -77,2・113.8・122.
2・132.5-■ 〃I COO-QC@II,
? -36.5・46.0・58.3 − −@ 〃
I Coo -Cs11+,'29.4・43.2
'55.4 *@ 〃l C0(1-0C
a11+t・27.6-42.5・56.9 - Example 2 4-octyloxy-14-decyloxy-1 and 4-dodecyloxy-4° instead of 4-hexyloxy-4°-hydroxybiphenyl, respectively Optically active compounds (1) to (4) were produced in the same manner as in Example 1, except that -hydroxybiphenyl was used. The phase transition temperatures of these compounds are shown in Table 1.

Example 3 The above-mentioned document of Kitakaze et al. using dioctyl 2-methyl-2-fluoromalonate! Optically active octyl hydrogen 2-methyl-2-fluoromalonate was obtained by the method described above. Acid chloride was produced from this compound in the same manner as in Example 1. Also, instead of 4-hexyloxy-4°-hydroxybiphenyl, 4-octyloxy-4°-hydroxybiphenyl, 4-octyl-4°-hydroxybiphenyl, octyl 4-hydroxy-4-biphenylcarboxylate, and caprylic acid-4 -Hydroxybiphenyl, 4°-human axy-4-biphenylcarboxylic acid-4''-ofdelphenyl, 4-hydroxy-4-biphenylcarboxylic acid-
Example 1 except that 4"-octyloxyphenyl, 4°-octyloxyphenyl 4-hydroxybenzoate, 4-octylphenyl 4-hydroxybenzoate, and 4°-hydroxybiphenyl 4-octyloquinebenzoate were used. Compounds ① to ＠ were produced in the same manner.

The phase transition temperatures of these compounds are shown in Table 1.

Example 4 Weight ratio of compound (1) and optically active 4-(2-methylbutyloxycarbonyl)phenyl 4-ctyloxybenzoate (compound where n=8 in V in the film) which is a diester liquid crystal A 20:80 mixture was prepared and the response to an electric field was investigated in the same manner as in Example 1.
It showed a clear response in the range of 43°C, and the magnitude of spontaneous polarization was 26 nC/as". Since the spontaneous polarization value of diester liquid crystal alone is about 3 nC/as", by mixing compound This means that a significant improvement in spontaneous polarization has been achieved.

Example 5 Weight ratio of the compound [phase] and optically active -4-(2-methylbutyloxycarbonyl)-4-biphenylcarboxylic acid-4''-octyloxyphenyl (-compound in the film = 8) A 10:90 mixture was prepared and Example 1
As a result of investigating the response to electric field in the same manner as 74-8
A clear response was shown in the range of 5°C.

Moreover, the magnitude of spontaneous polarization was 18 nC/as''.

Since the value of spontaneous polarization of this biphenylcarboxylic acid ester alone is about 3 nC/am', it can be seen that a significant improvement in spontaneous polarization was achieved by mixing the compound [stock].

Example 6 A mixture of Compound (1) and 4°-(2-methylbutyloxycarbonyl)phenyl 4-year-old ctyloxybenzoate, a smectic liquid crystal produced from racemic 2-methylbutanol, in a weight ratio of 10:90 was prepared. And examples! As a result of investigating the response to electric field in the same manner as 22
．． A clear response was shown in the range of 5 to 43°C, and the domain orientation was also good. Also, the magnitude of spontaneous polarization is 21
nC/cm'. Since there is no spontaneous polarization in the smectic liquid crystal alone, a significant improvement in spontaneous polarization was achieved by mixing compound (1).

Example 7 Compound (1), compound [phase], and the weight ratio of 4-(2-methylbutyloxycarbonyl)phenyl 4-octyloxybenzoate, which is a smectic liquid crystal produced from racemic 2-methylbutanol, is 10: A 10:80 mixture was prepared and its response to an electric field was investigated in the same manner as in Example I. It showed a clear response in the range of 27-67°C, which was significantly broader than when each was used alone. It responded over a temperature range. In addition, the alignment state of the domains was also good. The magnitude of spontaneous polarization is 24 nC/c+a'
Met.

Since diester, which is a smectic liquid crystal, does not exhibit spontaneous polarization alone, by mixing compound (1) and [phase], a significant improvement in spontaneous polarization was achieved.

Example 8 Compound ■ and racemic smectic liquid crystal 4°
A mixture of -(2-methylbutyloxycarbonyl)-4=biphenylcarboxylic acid and 4''-octyloxyphenyl was prepared at a weight ratio of 15:85, and the response to an electric field was investigated in the same manner as in Example 1. 67.5-84
It showed a clear response in the temperature range of °C, and responded over a wider temperature range than when each was used alone. In addition, the alignment state of the domains was also good. The magnitude of the spontaneous polarization was 22 nC/am''. Since there is no spontaneous polarization in biphenylcarboxylic acid ester alone, which is a smectic liquid crystal, a significant improvement in spontaneous polarization was achieved by mixing compound ①. It turns out.

"Effects of the Invention" As explained above, according to the present invention, the following general formula (+
), among those represented by formula (T), by using an optically active compound represented by (II), (III) or (1'V) in the film, ... (II) or Chiral smectic C with ester bond
The above formula (
1) A liquid crystal composition in which the spontaneous polarization is increased by adding an optically active compound particularly represented by (II), (III) or (VI), and the temperature range of the liquid crystal phase is wide. You can do it by getting .

Applicant Nippon Telegraph and Telephone Co., Ltd. Voluntary amendment to the procedure) 1. Indication of the case Patent Application No. 23052 of 1988 2. Name of the invention (422”) Nippon Telegraph and Telephone Co., Ltd. 4. Agent address 2 Yaesu, Chuo-ku, Tokyo 6th floor, Tokyo Ekimae Building, 1-5 Chome (275) 3921-4 Contents of amendments to Column 6 of "Detailed Description of the Invention" of the Specification (1) On page 9, line 10 of the specification, "・・・・・・(I
)” should be corrected to “→(1)”.

(2) "Table 1" on page 13 of the specification is corrected as shown in the attached sheet.

(3) In the fourth line of page 15 of the specification, "hydroxybiphenyl-" is corrected to "hydroxyphenyl."

(4) “Achieved” on the second line from the bottom of page 15 of the specification
I corrected it to ``I was able to achieve it.''

(5) "2-methylbutyloxycarbonyl" is corrected to "r2-methylbutyl" in lines 1 and 2 on page 16 and line 2 on page 18 of the specification.

(6) On page 16, line 17 of the specification: “Phenyl.

``The weight ratio of 10:90'' is replaced by ``phenyl (
- weight ratio of compound (n'==8 in ■ in the film) to 10
:90's,” he corrected.

Compound R3ρ X ■ Ct II s 2 0 ■
〃20 ■ 〃20 ■ 〃20 ■ Cel+,, 2 0■
“ 2 − ■ 〃2COO ■ 〃20CO @ 00C, l+, 71 Co.

table ! R2Cry SX SA N” IC
, II, 3 ・54.6 ・58.5 ・64.2-・C
, Il+7 ・60.7・67.4・69.3−・C
,. ! (,,-57,2-62,5-66,0-C1t
llts・56.0・67.4・69.2-・Ca
11+□・55,3・63.8・75.4−・C,1
1,7'-48,2-56,1-62,6-・C,I
I, -53,2-57,6・68.5-C7+1
15 ・45.3・49.3・66.6-・Ca11
．． 7・64.0・71.2・116.5・128.7・
OC, +1.7・77.2・83.8・122.2・1
32.5・0C-1117・36.5・46.0・58
．． 3-・Ca11. ,・29.4・43.2・55.4
-・0C811?・27.6・42.5・56,9-・
Procedural amendment letter 1, Indication of the case Patent Application No. 23052 of 1988 2, Name of the invention Optically active compound and liquid crystal composition 3, Relationship to the case by the person making the amendment Patent applicant address Yaesu, Chuo-ku, Tokyo 2-1-5 Tokyo Ekimae Building 6th floor (275) 3921-4 (1) 1 of the procedure correction report submitted on July 20, 1988
6. Amendment 6, Contents of the amendment (1) In (5) of the column "6. Contents of the amendment", it is written [in the 1st to 2nd lines of page 16 and the 2nd line of page 18 of the specification]. [Page 16, lines 2-3 and 18 of the specification]
Correct J on the third line of the page.

(2) Correct Table 1 as shown in the attached sheet.

Table 1 Compound R, 0, X R.

■ C2H520C81113 ■〃〃20　C,H,.

■〃2ocIoH21 ■〃〃20　C, 21+.

■ C, 11,720C, +(,,.

■〃〃〃〃　Cllll17 ■ 12 COOC, 11, 7 ■ // 20cOC7H,.

Claims (3)

[Claims] (1) General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・( I
) (However, R_1 represents an alkyl group having 1 to 18 carbon atoms,
R_2 represents an alkyl group having 4 to 18 carbon atoms, a 4-alkylphenyl group or a 4-alkyloxyphenyl group,
C^* represents an asymmetric carbon, l represents 1 or 2, and X represents -O
-, -COO-, -OCO- or a single bond). (2) Optically active smectic C with ester bond
A liquid crystal composition comprising a component consisting of a liquid crystal compound or a smectic C liquid crystal compound and an optically active compound represented by the following general formula (II), (III) or (IV). ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(III
) ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(IV) (However, C^* indicates an asymmetric carbon, m is 1 to 18, n
represents an integer from 4 to 18) (3) If the optically active smectic C liquid crystal compound having an ester bond or the component consisting of the smectic C liquid crystal compound is a compound represented by the following general formula (V) or (VI) (however, if it is a smectic liquid crystal compound, then
3. The liquid crystal composition according to claim 2, wherein ^* represents C. ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(V) ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(VI) (However, in the formula, n = an integer from 4 to 18 )