JPH069503A - Optically inactive low-molecular compound - Google Patents

Abstract

PURPOSE:To obtain an optically inactive low-molecular compound capable of providing a ferroelectric liquid crystal composition having a large tilt angle even by its addition into a liquid crystal composition so as to improve electric field responsiveness of the liquid crystal composition. CONSTITUTION:The compound of formula I (R<1> is formula II to VII, etc.; R<2> is 4-20C optically inactive alkyl; l and m are 0-10; n is 1-10; k is 1-20; Y is single bond, O, COO or OCO), e.g. a compound of formula VIII. This compound of formula VIII is obtained by converting a benzoic acid derivative into an acid chloride according to a pathway expressed by the reactional formula, then reacting the resultant acid chloride with a hydroxyphenylpyrimidine derivative and further reacting the obtained compound with trimethylacetic acid.

Description

Detailed Description of the Invention

FIELD OF THE INVENTION The present invention relates to a non-optically active low molecular weight compound which is preferably used as a liquid crystal material in the field of optoelectronics.

2. Description of the Related Art In order to improve the electric field response of a ferroelectric polymer liquid crystal, a polymer liquid crystal compound has a heterocyclic skeleton,
A ferroelectric polymer liquid crystal composition to which a non-optically active low molecular weight liquid crystal compound exhibiting a smectic C phase is added is known (JP-A-4-59890). However, in the conventionally known ferroelectric polymer liquid crystal composition, when the addition amount of the low molecular weight liquid crystal compound is increased, the tilt angle of the ferroelectric polymer liquid crystal composition is largely decreased, resulting in poor contrast. There is a problem of doing. As the non-optically active low molecular weight compound having a branched alkyl group, the following compounds [1] to [33] are disclosed in German Patent Application Publication No. 4003012.
(Compounds [1] to [32]) and EP-A-0477901 (Compound [33]).

[Chemical 3]

[Chemical 4] However, even if these low molecular weight compounds are added to a ferroelectric polymer liquid crystal to prepare a liquid crystal composition, there is a problem in that crystals are separated in several days and layer separation occurs, resulting in lack of long-term stability. is there.

DISCLOSURE OF THE INVENTION The present invention provides a ferroelectric liquid crystal having a large tilt angle even when it is added to the composition in order to improve the electric field response of the liquid crystal composition when preparing the ferroelectric liquid crystal composition. PROBLEM TO BE SOLVED: To provide a novel non-optically active low molecular compound capable of providing a composition having a long-term stability in which a crystalline liquid crystal composition can be obtained and crystals are hardly precipitated when added to a ferroelectric polymer liquid crystal. And

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that they have a specific branched alkyl group at the end of the molecule, and further have a branched central carbon and skeleton. It has been found that a non-optically active low molecular weight compound in which two functional groups composed of heteroatoms such as COO and O are introduced between the compound and the moiety gives a ferroelectric liquid crystal composition having a large tilt angle. Furthermore, they have found that even if this compound is added to a ferroelectric polymer liquid crystal, it is unlikely to cause crystallization and layer separation. The present invention has been completed based on these findings. That is, the present invention provides a non-optically active low molecular weight compound represented by the following general formula.

[Chemical 5] (In the formula, R ¹ is

[Chemical 6] R ² is a non-optically active alkyl group having 4 to 20 carbon atoms, l is an integer of 0 to 10, m is an integer of 0 to 10, and n is 1
-10 integer, k 1-20 integer, Y single bond, O, CO
Represents O or OCO. ) The novel non-optically active low molecular weight compound of the present invention is a stable liquid crystal having a large tilt angle even when added to a ferroelectric polymer liquid crystal when preparing a liquid crystal composition and hardly causing phase separation. The composition can be obtained and can be a useful constituent component in the preparation of, for example, a guest-host type driving liquid crystal composition. Specific examples of the branched alkyl group at the terminal portion of the non-optically active low molecular weight compound of the present invention include the following groups.

[Chemical 7] $ Specific examples of the non-optically active low molecular weight compound of the present invention include the following compounds.

[Chemical 8]

[Chemical 9]

EXAMPLES The present invention will now be described in detail based on examples, but the present invention is not limited thereto. Example 1 Synthesis of Compound (1) Compound (1) was synthesized according to the synthetic route shown below.

[Chemical 10] $ (1-1) Synthesis of compound (16) Benzoic acid derivative (14) 9.16 g toluene 50 ml
11.33 g of thionyl chloride and a few drops of pyridine were added to the solution, and the mixture was reacted at 65 ° C. for 4 hours. Attach an aspirator for 30 minutes at 65 ° C and then 1 hour at 80 ° C.
The solvent and excess thionyl chloride were distilled off. To the remaining oily substance, a solution of 1.88 g of pyridine in 50 ml of toluene and a hydroxyphenylpyrimidine derivative (15) 7.4.
A solution of 6 g of toluene in 50 ml was added dropwise. After reacting for 12 hours at room temperature, filtration was performed to remove salts. The solvent was distilled off from the filtrate under reduced pressure, and the residue was subjected to column chromatography (neutral alumina-filled precolumn, silica gel-filled main column, 10% ethyl acetate / 20% dichloromethane / n).
-Development with hexane) to obtain 9.31 g of the target compound (16) (yield 58%). ¹ H-
The analysis results (ppm) of NMR (TMS / CDCl ₃ ) are shown below. 8.55 (s, 2H) 4.00 (t, 2H) 8.45 (d, 2H) 3.38 (t, 2H) 8.10 (d, 2H) 2.58 (t, 2H) 7. 38 (d, 2H) 2.10 to 0.70 (m, 39
H) 6.90 (d, 2H) $ (1-2) Synthesis of compound (1) 2.77 g of trimethylacetic acid and 4.92 g of tetramethylammonium hydroxide pentahydrate were stirred at room temperature until a transparent liquid was obtained. After that, 50 ml of DMF was added. A solution of 9.20 g of compound (16) in 550 ml of DMF was added,
The reaction was carried out at 40 ° C for 12 hours. After completion of the reaction, the reaction mixture was poured into a dilute hydrochloric acid aqueous solution and extracted with dichloromethane. The organic layer was dried over magnesium sulfate (anhydrous) and then filtered, and the solvent was distilled off from the filtrate under reduced pressure. The residue was purified by column chromatography (filled with silica gel, 10% ethyl acetate / 20% dichloromethane / n-hexane development) to obtain 7.47 g of the target compound (1) (yield 79%). ¹ H-NMR (T
The analysis results (ppm) of MS / CDCl ₃ ) are shown below. 8.55 (s, 2H) 4.00 (m, 4H) 8.45 (d, 2H) 2.56 (t, 2H) 8.10 (d, 2H) 2.10 to 0.70 (m, 48
H) 7.39 (d, 2H) 6.90 (d, 2H) Further, the phase transition behavior (temperature lowering process) of the compound (1) observed by a polarization microscope was as follows. Iso → N → S _C → S ₁ → Cryst. 103 ° C. 88 ° C. 60 ° C. 40 ° C. (Iso: isotropic phase, N: nematic phase, S _C : smectic C phase, S ₁ : unidentified smectic phase, Crys
t. : Crystalline phase) $ Example 2 Synthesis of compound (2) Compound (2) was synthesized according to the synthetic route shown below.

[Chemical 11] $ (2-1) Synthesis of compound (18) By using hydroxybiphenylcarboxylic acid derivative (17) in place of hydroxyphenylpyrimidine derivative (15) and performing the same operation as in Example 1 (1-1), 2.80 g of the target compound (18) was obtained from 2.00 g of the compound (17) (yield 66%). ¹ H-NM
The analysis results (ppm) of R (TMS / CDCl ₃ ) are shown below. 8.05 (d, 2H) 4.00 (m, 4H) 8.04 (d, 2H) 3.35 (t, 2H) 7.57 (d, 2H) 2.10 to 0.85 (m, 35
H) 7.56 (d, 2H) 7.23 (d, 2H) 6.90 (d, 2H) $ (2-2) Synthesis of compound (2) Compound (18) was used in place of compound (16) Using the same procedure as in Example 1 (1-2), the desired compound (2) 0.7 was obtained from 1.80 g of the compound (18).
0 g was obtained (yield 38%). ¹ H-NMR (TMS / CDC
The analysis result (ppm) of l ₃ ) is shown below. 8.05 (d, 2H) 4.00 (m, 6H) 8.04 (d, 2H) 2.10 to 0.75 (m, 43)
H) 7.57 (d, 2H) 7.56 (d, 2H) 7.23 (d, 2H) 6.90 (d, 2H) Also, the phase transition behavior of the compound (2) by polarization microscope observation (temperature decrease). The process) was as follows. _{Iso → S A → S C →} Cryst. 133 ° C. 126 ° C. 68 ° C. (S _A : Smectic A phase) $ Example 3 Synthesis of compound (3) Compound (3) was synthesized according to the synthetic route shown below.

[Chemical 12] (3-1) Synthesis of compound (21) Instead of the carboxylic acid derivative (14), the compound (19) is used.
The compound (20) was used in place of the compound (15) and the same operation as in Example 1 (1-1) was carried out to obtain 0.77 g of the compound (20) and 0.80 g of the desired compound (21). Was obtained (yield 34%). ¹ H-NM
The analysis results (ppm) of R (TMS / CDCl ₃ ) are shown below. 8.25-6.75 (m, 12H) 4.00 (m, 4H) 3.38 (t, 2H) 2.10-0.75 (m, 35H) $ (3-2) Compound (3) Synthesis of compound (16) was replaced with compound (21), and the same operation as in Example 1 (1-2) was carried out. Four
1 g was obtained (yield 50%). ¹ H-NMR (TMS / CDC
The analysis result (ppm) of l ₃ ) is shown below. 8.25 to 6.75 (m, 12H) 4.00 (m, 6H) 2.10 to 0.75 (m, 44H) Further, the phase transition behavior of the compound (3) by polarization microscope observation (cooling process) Was as follows: _{Iso → S A → S C →} Cryst. 156 ° C. 146 ° C. 80 ° C. $ Example 4 Synthesis of compound (4) Compound (4) was synthesized according to the synthetic route shown below.

[Chemical 13] $ (4-1) Synthesis of compound (23) Compound (22) 1.08 g was obtained by substituting compound (22) for compound (15) and performing the same operation as in Example 1 (1-1). To the target compound (23) 2.
10 g was obtained (yield 70%). ¹ H-NMR (TMS / C
The analysis results (ppm) of DCl ₃ ) are shown below. 8.10 (d, 2H) 7.20 to 6.80 (m, 6H) 4.00 (m, 4H) 3.86 (t, 2H) 2.10 to 0.80 (m, 33H) $ ( 4-2) Synthesis of compound (4) By using compound (23) instead of compound (16) and performing the same operation as in Example 1 (1-2), 2.10 g of compound (23) was obtained. Compound (4) 1.5
0 g was obtained (yield 70%). ¹ H-NMR (TMS / CDC
The analysis result (ppm) of l ₃ ) is shown below. 8.10 (d, 2H) 7.20 to 6.80 (m, 6H) 4.00 (m, 6H) 2.10 to 0.75 (m, 42H) Further, the compound (4) observed by a polarizing microscope. The phase transition behavior (cooling process) of was as follows. _{Iso → S A → S C →} S 1 → Cryst. 57 ° C. 41 ° C. 31 ° C. 4 ° C. $ Example 5 Synthesis of compound (5) Compound (5) was synthesized according to the synthetic route shown below.

[Chemical 14] $ (5-1) Synthesis of compound (24) Using compound (20) instead of compound (15) and performing the same operation as in Example 1 (1-1), 1.15 g of compound (20) To the target compound (24) 2.
00g was obtained (yield 65%). ¹ H-NMR (TMS / C
The analysis results (ppm) of DCl ₃ ) are shown below. 8.10 (d, 2H) 7.20 to 6.80 (m, 6H) 4.00 (m, 4H) 3.87 (t, 2H) 2.10 to 0.85 (m, 35H) $ ( 5-2) Synthesis of compound (5) Using compound (24) instead of compound (16) and performing the same operation as in Example 1 (1-2), 2.00 g of compound (24) was obtained. Compound (5) 1.5
0 g was obtained (yield 72%). ¹ H-NMR (TMS / CDC
The analysis result (ppm) of l ₃ ) is shown below. 8.10 (d, 2H) 7.20 to 6.80 (m, 6H) 4.00 (m, 6H) 2.10 to 0.85 (m, 44H) Further, the compound (5) observed by a polarizing microscope. The phase transition behavior (cooling process) of was as follows. _{Iso → S A → S C →} S 1 → Cryst. 58 ° C. 45 ° C. 33 ° C. 18 ° C. $ Example 6 Synthesis of compound (6) Compound (6) was synthesized according to the synthetic route shown below.

[Chemical 15] $ (6-1) Synthesis of Compound (25) DMF 14 ml contains 60% oily sodium hydride 1.50
g, and further, a solution of 7.83 g of the hydroxyphenylpyrimidine derivative (15) in 50 ml of DMF was added dropwise at room temperature. After stirring at room temperature for 30 minutes as it was, a solution of 20.40 g of 1,8-dibromooctane in 50 ml of DMF was added dropwise, and the mixture was further stirred for 8 hours. After completion of the reaction, the reaction mixture was poured into water and extracted with dichloromethane. The organic layer was dried over anhydrous magnesium sulfate and then filtered, and the filtrate was distilled off under reduced pressure to obtain 52.80 g of a residue. Column chromatography (packing silica gel, developing 10% ethyl acetate / 20% dichloromethane / n-hexane)
The compound of interest (25) 7.
70 g was obtained (61% yield). ¹ H-NMR (TMS / C
The analysis results (ppm) of DCl ₃ ) are shown below. 8.50 (s, 2H) 8.33 (d, 2H) 7.00 (d, 2H) 4.10 (t, 2H) 3.36 (t, 2H) 2.60 (t, 2H) 2. 10-0.85 (m, 31H) $ (6-2) Synthesis of Compound (6) The compound (25) is used instead of the compound (16), and the same operation as in Example 1 (1-2) is performed. Thus, from 1.01 g of the compound (25), the target compound (6) 0.9
1 g was obtained (87% yield). ¹ H-NMR (TMS / CDC
The analysis result (ppm) of l ₃ ) is shown below. 8.50 (s, 2H) 8.33 (d, 2H) 7.00 (d, 2H) 4.10 (t, 2H) 4.00 (t, 2H) 2.60 (t, 2H) 2. 10-0.85 (m, 40H) Moreover, the phase transition behavior (temperature-decreasing process) of the compound (6) by a polarization microscope observation was as follows. _{Iso → S A → S C →} Cryst. 76 ° C. 54 ° C. 25 ° C. $ Example 7 Synthesis of compound (7) Compound (7) was synthesized according to the synthetic route shown below.

[Chemical 16] (7-1) Synthesis of Compound (27) Example 6 (6-1) using Compound (26) in place of Compound (15) and 1,12-Dibromododecane in place of 1,8-Dibromooctane. By carrying out the same operation as above, 3.28 g of the desired compound (27) was obtained from 3.00 g of the compound (26) (yield 60%). ¹ H-NM
The analysis results (ppm) of R (TMS / CDCl ₃ ) are shown below. 8.40 (s, 2H) 8.25 (d, 2H) 6.95 (d, 2H) 4.05 (m, 4H) 3.36 (t, 2H) 2.10 to 0.85 (m, 35H) $ (7-2) Synthesis of Compound (7) Compound (27) 1 was prepared by the same procedure as in Example 1 (1-2) using compound (27) instead of compound (16). The target compound (7) 1.0 from 10 g
3 g was obtained (yield 91%). ¹ H-NMR (TMS / CDC
The result of analysis (ppm) of l ₃ ) is shown below, and the NMR chart is shown in FIG. 8.40 (s, 2H) 8.25 (d, 2H) 6.95 (d, 2H) 4.05 (m, 6H) 1.90 to 0.85 (m, 44H) In addition, by polarization microscope observation The phase transition behavior (temperature lowering process) of the compound (7) was as follows. $ Examples 8, 9, 10, 11, 12, 13, 14 and Comparative Example 1 Ferroelectric polymer liquid crystal compound (28) having the following structure
To the compounds (1), (2), (3), (4), and
A liquid crystal composition containing 30% by weight of (5), (6) and (7) was prepared. The liquid crystal composition was prepared by dissolving all the constituent components of the composition in 1.5 times the weight of dichloromethane to form a uniform solution, and then distilling off the solvent. Further, by sandwiching these compositions between two glass substrates with ITO electrodes, a cell thickness of about 3 μm was obtained by the shearing method.
An oriented cell of m was prepared and the tilt angle was measured while applying an electric field of ± 15 MV / m. Further, for comparison, a known compound (29) having no branched alkyl group at the molecular end of the ferroelectric polymer liquid crystal compound (28) (P, manufactured by Midori Kagaku Co., Ltd.)
-1008) was added to the composition, and cells were prepared in the same manner as in Examples 8 to 14, and the tilt angle (2θ) was measured in the same manner.

[Chemical 17] The results of Examples 8 to 14 and Comparative Example 1 are shown in Table 1.

[Table 1] $ Example 15 Synthesis of compound (8) Compound (8) was synthesized according to the synthetic route shown below.

[Chemical 18] $ (±) -2-methylvaleric acid 0.232 g and tetramethylammonium hydroxide pentahydrate 0.
After stirring 362 g at room temperature until it became a transparent liquid, D
4 ml of MF was added. Compound (16) 0.680 g of D
A 40 ml MF solution was added and reacted at 40 ° C. for 12 hours. After completion of the reaction, the reaction mixture was poured into a dilute hydrochloric acid aqueous solution and extracted with dichloromethane. The organic layer was dried over magnesium sulfate (anhydrous) and then filtered, and the solvent was distilled off from the filtrate under reduced pressure. The residue was purified by column chromatography (filled with silica gel, 10% ethyl acetate / 20% dichloromethane / n-hexane development) to obtain 0.601 g of the desired compound (8) (yield 84.1).
%). ¹ H-NMR (TMS / CDCl ₃ ) analysis results (pp
m) is shown below. 8.61 (s, 2H) 2.62 (t, 2H) 8.48 (d, 2H) 2.43 (m, 1H) 8.15 (d, 2H) 1.86-1.20 (m, 40
H) 7.32 (d, 2H) 1.14 (d, 3H) 6.97 (d, 2H) 0.90 (m, 6H) 4.05 (m, 4H) Moreover, the compound (8 The phase transition behavior of () (temperature lowering process) was as follows. _{Iso → N → S A → Cryst} . 102 ° C. 89 ° C. 19 ° C. $ Example 16 Synthesis of compound (9) Compound (9) was synthesized according to the synthetic route shown below.

[Chemical 19] $ (±) -2- (±) instead of methylvaleric acid
Compound (16) 0.68 was prepared by the same procedure as in Example 15 using -3-methylvaleric acid.
0.634 g of the target compound (9) was obtained from 0 g (yield 88.7%). ¹ H-NMR of the obtained compound
The results (ppm) of the (TMS / CDCl ₃ ) analysis are shown below. 8.62 (s, 2H) 2.63 (t, 2H) 8.48 (d, 2H) 2.30 (m, 1H) 8.15 (d, 2H) 2.10 (m, 1H) 7. 33 (d, 2H) 1.98-1.18 (m, 39
H) 6.97 (d, 2H) 0.90 (m, 9H) 4.06 (m, 4H) Further, the phase transition behavior (temperature-decreasing process) of the compound (9) observed by a polarization microscope is as follows. Met. _{Iso → N → S A → S} 1 → glass 105 ℃ 93 ℃ 43 ℃ 32 ℃: Compound (10) was synthesized according to the synthetic route shown in synthesis following (Glass glass state) $ Example 17 Compound (10).

[Chemical 20] Compound (25) 1 was obtained by the same procedure as in Example 15 using isovaleric acid instead of $ (±) -2-methylvaleric acid and compound (25) instead of compound (16). 0.93 g of the target compound (10) was obtained from 0.01 g (yield 89%). Result of ¹ H-NMR (TMS / CDCl ₃ ) analysis of the obtained compound (pp
m) is shown below. 8.56 (s, 2H) 2.10 (m, 1H) 8.34 (d, 2H) 1.80 (m, 2H) 6.97 (d, 2H) 1.62 (m, 2H) 4. 05 (m, 4H) 1.54-1.20 (m, 24
H) 2.58 (t, 2H) 0.95 (d, 6H) 2.18 (d, 2H) 0.87 (t, 3H) Further, the phase transition behavior of the compound (10) (temperature decrease The process) was as follows. _{Iso → S A → S C →} Cryst. 52.3 ° C. 33 ° C. 10 ° C. $ Example 18 Synthesis of Compound (11) Compound (11) was synthesized according to the synthetic route shown below.

[Chemical 21] By using isobutyric acid instead of $ (±) -2-methylvaleric acid and performing the same operation as in Example 15, from the compound (16) 0.680 g to the target compound (11) 0 .493 g was obtained (yield 71.
8%). ¹ H-NMR (TMS / CDC of the obtained compound
l ₃ ) The results (ppm) of the analysis are shown below. 8.61 (s, 2H) 2.63 (t, 2H) 8.48 (d, 2H) 2.54 (m, 1H) 8.15 (d, 2H) 1.87-1.20 (m, 36
H) 7.32 (d, 2H) 1.16 (d, 6H) 6.98 (d, 2H) 0.88 (t, 3H) 4.05 (m, 4H) In addition, the compound ( The phase transition behavior (temperature lowering process) of 11) is as follows. Iso → N → S _C → S ₁ → Cryst. 115 ° C 99 ° C 38 ° C 32 ° C $ Example 19 Synthesis of Compound (12) Compound (12) was synthesized according to the synthetic route shown below.

[Chemical formula 22] $ (19-1) Synthesis of compound (31) 1.32 g of benzoic acid derivative (30), 1.25 g of hydroxyphenylpyrimidine derivative (15), DCC1.4
A solution of 0 g and 0.156 g of DMAP in 40 ml of toluene was stirred at room temperature for 12 hours. Then dichloromethane 20
The reaction solution was diluted by adding 0 ml. Filtration was performed, and the solvent was distilled off from the filtrate under reduced pressure to obtain 6.76 g of a residue. This is subjected to column chromatography (pre-column packed with neutral alumina, main column packed with silica gel, 10% ethyl acetate / 30% dichloromethane / n-hexane development).
The target compound (31) 1.
75 g was obtained (yield 64.5%). ¹ of the resulting compound
The result (ppm) of 1 H-NMR (TMS / CDCl ₃ ) analysis is shown below. 8.62 (s, 2H) 4.00 (t, 2H) 8.48 (d, 2H) 3.37 (t, 2H) 8.15 (d, 2H) 2.62 (t, 2H) 7. 33 (d, 2H) 1.86-0.88 (m, 31
H) 6.97 (d, 2H) $ (19-2) Synthesis of compound (12) Isovaleric acid instead of (±) -2-methylvaleric acid, compound (31) instead of compound (16) Was performed in the same manner as in Example 15 to obtain 0.502 g of the desired compound (12) from 0.680 g of the compound (31) (yield 71.4%).
The results (ppm) of ¹ H-NMR (TMS / CDCl ₃ ) analysis of the obtained compound are shown below. 8.62 (s, 2H) 2.64 (t, 2H) 8.48 (d, 2H) 2.19 (d, 2H) 8.15 (d, 2H) 2.10 (m, 1H) 7. 33 (d, 2H) 1.89-1.20 (m, 28
H) 6.98 (d, 2H) 0.96 (d, 6H) 4.06 (m, 4H) 0.88 (t, 3H) Also, the phase transition behavior of the compound (12) by polarization microscope observation (temperature decrease). The process) was as follows. Iso → N → S _C → Cryst. 116 ° C. 93 ° C. 51 ° C. $ Example 20 Synthesis of compound (13) Compound (13) was synthesized according to the synthetic route shown below.

[Chemical formula 23] Compound (31) was obtained by the same procedure as in Example 15 using isobutyric acid instead of $ (±) -2-methylvaleric acid and compound (31) instead of compound (16). 0.496 g of the target compound (13) was obtained from 0.680 g (yield 72.1%).
The results (ppm) of ¹ H-NMR (TMS / CDCl ₃ ) analysis of the obtained compound are shown below. 8.62 (s, 2H) 2.63 (t, 2H) 8.49 (d, 2H) 2.55 (m, 1H) 8.16 (d, 2H) 1.87-1.20 (m, 28
H) 7.33 (d, 2H) 1.17 (d, 6H) 6.97 (d, 2H) 0.88 (t, 3H) 4.06 (m, 4H) In addition, the compound ( The phase transition behavior (temperature lowering process) of 13) is as follows. _{Iso → N → S C → glass} 119 ℃ 88 ℃ 39 ℃ $ Examples 21-25 and 26 Ferroelectric liquid crystal polymer compound (28), the compounds of the present invention (8), (9 ), (10), (11), (12) and (13) were added at 30% by weight to prepare a liquid crystal composition.
The liquid crystal composition was prepared by dissolving all the constituent components of the composition in 1.5 times the weight of dichloromethane to form a uniform solution, and then distilling off the solvent. Furthermore,
These compositions were sandwiched between two glass substrates with ITO electrodes, an alignment cell having a cell thickness of about 3 μm was prepared by a shearing method, and a tilt angle (2θ) was measured while applying an electric field of ± 15 MV / m. . The results are shown in Table 2. Further, the obtained oriented cells were allowed to stand at 2 ° C. and the state of crystal precipitation was observed with a microscope. The results are shown in Table 3.

[Table 2] From Table 1 and Table 2, it can be seen that the compound of the present invention can prepare a liquid crystal composition having a large tilt angle. Comparative Examples 2 to 34 Known compounds [1] to [33] 30% by weight described in German Patent Application Publication No. 4003012 and European Patent Application Publication No. 0477901 and ferroelectric polymer liquid crystals. A liquid crystal composition containing 70% by weight of the compound (28) was prepared in the same manner as in Examples 21 to 26, and an alignment cell was prepared in the same manner. The orientation cell obtained was left at 2 ° C., and the state of crystal precipitation was observed with a microscope. The results are shown in Table 3.

[Table 3] $ A liquid crystal composition is prepared by mixing the above-mentioned known non-optically active compound having at most one kind of functional group consisting of a hetero atom in the alkylene group between the branched central carbon and the skeleton with a polymer liquid crystal compound. In the case of causing the phase separation due to crystallization in a short time, the alkylene group has -COO- and-.
A liquid crystal composition containing a non-optically active low molecular weight compound of the present invention having two O-functional groups is less likely to crystallize, and a liquid crystal composition excellent in long-term stability in which phase separation due to crystallization is suppressed is provided. You can see that you can get it.

INDUSTRIAL APPLICABILITY According to the present invention, by blending with a ferroelectric polymer liquid crystal, it is possible to obtain a stable liquid crystal composition having a large tilt angle and causing no phase separation for a long period of time. A new compound having

[Brief description of drawings]

1 is an NMR chart of the non-optically active compound of the present invention obtained in Example 7. FIG.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C09K 19/20 Z 7457-4H 19/34 7457-4H

Claims (1)

[Claims] 1. A non-optically active low-molecular compound represented by the following general formula. [Chemical 1] (In the formula, R ¹ is R ² is a non-optically active alkyl group having 4 to 20 carbon atoms, l is an integer of 0 to 10, m is an integer of 0 to 10, and n is 1
-10 integer, k 1-20 integer, Y single bond, O, CO
Represents O or OCO. )