JP2736535B2 - Optically active ester compound and liquid crystal composition containing the compound - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a novel optically active ester compound and a liquid crystal composition containing the same, and more particularly, it is useful as a component of a ferroelectric liquid crystal composition. And an optically active ester compound and a ferroelectric liquid crystal composition containing the same.

[Conventional technology and its problems]

Liquid crystal devices began to be used in displays such as watches and calculators, and are now widely used in pocket televisions, various displays, optoelectronic devices, and the like. Most are of a TN type display system, and a liquid crystal material belonging to a nematic phase is used. Since the TN type display system is a light receiving type, it has the features of not tired eyes and extremely low power consumption, but has the disadvantage that the response speed is slow and the display cannot be seen depending on the viewing angle.
However, recently, a display system using a ferroelectric liquid crystal has been devised to improve these disadvantages. In the case of a display device using this ferroelectric liquid crystal, as in the case of a TN liquid crystal, several types of liquid crystal compounds or non-liquid crystal compounds are mixed in order to satisfy many characteristics in actual use. Liquid crystal composition.

Based on such a concept, for example, an optically active 2-methyl-1,3-propanediol compound (JP-A-63-44548)
To use as a component of a ferroelectric liquid crystal composition. However, although the response speed of the ferroelectric liquid crystal composition using these compounds as one component is improved to some extent, it is still not sufficient, and further improvement has been desired for practical use.

[Means for solving the problem]

In view of the above situation, the present inventors have conducted intensive studies to find a useful optically active compound for obtaining a ferroelectric liquid crystal composition having an excellent response speed, and as a result, are represented by the following general formula (I). It has been found that a novel optically active ester compound is a very suitable compound to be used for the above purpose.

(Wherein R represents an alkyl group having 1 to 18 carbon atoms or an alkoxy group having 1 to 18 carbon atoms, Z represents a direct bond, -COO
-Or -OCO-, Each independently represents a 1,4-phenylene group or a 2,5-pyrimidinylene group, a and b each represent 0 or 1, c represents 1 or 2, a + b + c = 3, *
Represents an asymmetric carbon atom. The compound represented by the general formula (I) will be described in more detail.

Examples of the alkyl group having 1 to 18 carbon atoms represented by R include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, lauryl, myristyl, palmityl, stearyl and the like. Examples of the alkoxy group having 1 to 18 carbon atoms include an alkoxy group derived from the above alkyl group.

Examples of the optically active ester compound represented by the general formula (I) include the following compounds.

These compounds can be mixed to form a liquid crystal composition by mixing two or several kinds at an arbitrary ratio depending on the purpose of use.

〔Example〕

Hereinafter, the present invention will be described with reference to examples. However, the present invention is not limited by the following examples.

Example 1 (Synthesis Example 1) Synthesis of (S) -2- (4-octylphenyl) -5- (4-citronelloyloxyphenyl) pyrimidine 0.36 g of 2- (4-octylphenyl) -5- (4-hydroxyphenyl) pyrimidine, 0.17 g of (S) -citronellic acid, N, N'-dicyclohexylcarbodiimide 0.
21 g and 0.02 g of 4-pyrrolidinopyridine were dissolved in 10 ml of methylene chloride and stirred at room temperature for 3 hours. After the precipitated dicyclohexylurea was filtered off, the filtrate was desolvated.
The solvent removal residue was purified on a silica gel column using n-hexane / ethyl acetate (88/12) as a developing solvent, and then recrystallized from ethyl alcohol / benzene / acetone (60/25/15) to give (S)- 2- (4-octylphenyl) -5
0.38 g of white solid of-(4-citroneroyloxyphenyl) pyrimidine was obtained.

As a result of infrared spectroscopy, the obtained product had the following characteristic absorption and was confirmed to be the desired product.

^{2930cm -1 (s), 2860cm -1} (w), 1755cm -1 (s), 1615cm -1 (w), 1530cm -1 (w), 1445cm -1 (s), 1380cm -1 (m), 1300cm ^{-1 (w), 1215cm -1 (} m), 1175cm -1 (m), 1140cm -1 (m), 850cm -1 (m), 800cm -1 (m) example 2 (synthesis example 2) (S ) -2- (4-decyloxyphenyl) -5- (4
Synthesis of (citronelloyloxyphenyl) pyrimidine 2- (4-octylphenyl) -5- (4
The reaction was carried out in exactly the same manner as in Example 1 except that 0.40 g of 2- (4-decyloxyphenyl) -5- (4-hydroxyphenyl) pyrimidine was used instead of -hydroxyphenyl) pyrimidine, and the reaction was carried out using n-hexane / Ethyl acetate (9 /
After purifying with a silica gel column using 1) as a developing solvent,
Recrystallize with ethyl alcohol / benzene (7/3)
(S) -2- (4-decyloxyphenyl) -5- (4
0.30 g of a white solid of (citroneroyloxyphenyl) pyrimidine was obtained.

As a result of infrared spectroscopy, the obtained product had the following characteristic absorption and was confirmed to be the desired product.

^{2930cm -1 (s), 2860cm -1} (w), 1755cm -1 (s), 1610cm -1 (m), 1585cm -1 (m), 1530cm -1 (w), 1515cm -1 (w), 1420cm ^{-1 (s), 1380cm -1 (} w), 1300cm -1 (w), 1255cm -1 (s), 1210cm -1 (w), 1175cm -1 (m), 1140cm -1 (w), 845cm - ¹ (m), 800 cm ^-1 (m) Example 3 (Synthesis Example 3) Synthesis of (S) -4'-citronelloyloxy-4-biphenylcarboxylic acid-4-octylphenyl ester 4'-benzyloxy-4-biphenylcarboxylic acid 1.
52 g, 1.03 g of p-octylphenol, 1.03 g of N, N'-dicyclohexylcarbodiimide and 0.10 g of 4-pyrrolidinopyridine were dissolved in 60 ml of methylene chloride and stirred at room temperature for 2 hours. After the precipitated dicyclohexylurea was filtered off, the filtrate was desolvated. Methyl alcohol was added to the solvent removal residue, and the insoluble matter in methyl alcohol was recrystallized from ethyl alcohol / benzene (4/6) to give a plate-like 4'-benzyloxy-4-biphenylcarboxylic acid 4-octylphenyl ester. 2.06 g of crystals were obtained. (Melting point 171.3
° C, clearing point 215.7 ° C) 2.0 g of the obtained 4'-benzyloxy-4-biphenylcarboxylic acid 4-octylphenyl ester and 0.3 g of 5% palladium carbon were added to 30 ml of ethyl alcohol.
After hydrogenation under normal pressure at 60 ° C. for 5 hours, the mixture was filtered and the solvent was removed. The solvent removal residue was purified by a silica gel column using n-hexane / ethyl acetate (7/3) as a developing solvent to obtain 0.98 g of 4'-hydroxy-4-biphenylcarboxylic acid-4-octylphenyl ester as a white powder.

(Melting point: 169.5 ° C., clearing point: 189.5 ° C.) Further, 0.40 g of this 4′-hydroxy-4-biphenylcarboxylic acid-4-octylphenyl ester, (s)
-Citronellic acid 0.17 g, N, N'-dicyclohexylcarbodiimide 0.21 g and 4-pyrrolidinopyridine 0.02 g
Was dissolved in 10 ml of methylene chloride and stirred at room temperature for 3 hours. After the precipitated dicyclohexylurea was filtered off, the filtrate was desolvated. The desolvation residue was purified on a silica gel column using n-hexane / ethyl acetate (9/1) as a developing solvent.
The objective (S) -4'-citronelloyloxy-4-biphenylcarboxylic acid-4-octylphenyl ester was obtained as 0.48 g of white powder.

As a result of infrared spectroscopy, the obtained product had the following characteristic absorption and was confirmed to be the desired product.

^{2920cm -1 (m), 2850cm -1} (w), 1745cm -1 (s), 1725cm -1 (s), 1605cm -1 (m), 1505cm -1 (m), 1460cm -1 (w), 1380cm ^{-1 (w), 1275cm -1 (} s), 1190cm -1 (s), 1170cm -1 (w), 1140cm -1 (m), 1080cm -1 (m), 840cm -1 (m), 770cm - ¹ (m) Example 4 (Synthesis Example 4) Synthesis of (S) -4- (5-octylpyrimidi-2-yl) phenyl-4-citroneroyloxybenzoate 1.00 g of P-benzyloxybenzoic acid, 1.25 g of 2- (4-hydroxyphenyl) -5-octylpyrimidine, N,
0.90 g of N'-dicyclohexylcarbodiimide and 4-
Pyrosinopyridine (0.09 g) was dissolved in 50 ml of methylene chloride and stirred at room temperature for 3 hours. After the precipitated dicyclohexylurea was filtered off, the filtrate was desolvated. The solvent removal residue was recrystallized from ethyl alcohol / benzene (7/3) to give 4-
1.78 g of needle crystals of (5-octylpyrimidi-2-yl) phenyl-4-benzyloxybenzoate were obtained.

(Melting point: 126.8 ° C, clearing point: 181.3 ° C) 4- (5-octylpyrimidin-2-yl) obtained
1.78 g of phenyl-4-benzyloxybenzoate and 0.3 g of 5% palladium carbon were added to 30 ml of ethyl alcohol.
And hydrogenated at 60 ° C. under normal pressure for 2 hours, followed by hot filtration and recrystallization as it is to give 0.79 of colorless needle crystals of 4- (5-octylpyrimidi-2-yl) phenyl-4-hydroxybenzoate. g was obtained. (Melting point: 186-188 ° C.) Further, 1.00 g of 4- (5-octylpyrimidi-2-yl) phenyl-4-hydroxybenzoate,
0.17 g of (s) -citronellic acid, 0.21 g of N, N'-dicyclohexylcarbodiimide and 0.02 g of 4-pyrrolidinopyridine were dissolved in 10 ml of methylene chloride and stirred at room temperature for 3 hours. After the precipitated dicyclohexylurea was filtered off, the filtrate was desolvated. The solvent removal residue was purified by silica gel column using n-hexane / ethyl acetate (87/13) as a developing solvent. Recrystallization from ethyl alcohol gave 0.42 g of the desired (S) -4- (5-octylpyrimidi-2-yl) phenyl-4-citronelloyloxybenzoate needle crystals.

As a result of infrared spectroscopy, the obtained product had the following characteristic absorption and was confirmed to be the desired product.

^{2920cm -1 (m), 2850cm -1} (w), 1745cm -1 (s), 1730cm -1 (s), 1600cm -1 (m), 1585cm -1 (m), 1540cm -1 (w), 1500cm ^{-1 (w), 1430cm -1 (} s), 1270cm -1 (s), 1195cm -1 (s), 1165cm -1 (s), 1135cm -1 (m), 1080cm -1 (m) example 5 (Synthesis Example 5) (S) -4′-octyloxybiphenyl-4-yl-
Synthesis of 4-citroneroyloxybenzoate Instead of 2- (4-hydroxyphenyl) -5-octylpyrimidine of Example 4, 4'-octyloxy-
The reaction was carried out in exactly the same manner as in Example 4 except that 1.31 g of 4-hydroxybiphenyl was used, followed by recrystallization with ethyl alcohol / benzene (1/1) to give 4'-octyloxybiphenyl-4-yl-4-benzyl. 1.49 g of oxybenzoate plate crystals were obtained.

(Melting point 144.8 ° C, clearing point 218.1 ° C) Then, the resulting 4'-octyloxybiphenyl-
Hydrogenation was carried out in the same manner as in Example 4 using 1.49 g of 4-yl-4-benzyloxybenzoate to give 4'-hydroxy-4.
1.16 g of white powder of -biphenylcarboxylic acid-4-octylphenyl ester was obtained.

(Melting point: 207-208 ° C.) Further, instead of 4′-hydroxy-4-biphenylcarboxylic acid-4-octylphenyl ester of Example 3, the obtained 4′-hydroxy-4-biphenylcarboxylic acid-4-octyl was used. The reaction was carried out in the same manner as in Example 3 except that 0.42 g of phenyl ester was used.
After purification on a silica gel column using ethyl acetate (9/1) as a developing solvent, the product was further recrystallized from ethyl alcohol.
The desired (S) -4'-octyloxybiphenyl-4-
Colorless fine plate-like crystals of yl-4-citronelloyloxybenzoate were obtained.

As a result of infrared spectroscopy, the obtained product had the following characteristic absorption and was confirmed to be the desired product.

^{2925cm -1 (m), 2860cm -1} (w), 1755cm -1 (s), 1735cm -1 (s), 1605cm -1 (m), 1500cm -1 (m), 1470cm -1 (w), 1370cm ^-1 (w), 1280 cm ^-1 (s), 1210 cm ^-1 (s), 1165 cm ^-1 (m), 1145 cm ^-1 (w), 1080 cm ^-1 (m), 805 cm ^-1 (w) Each of the compounds synthesized in Examples 1 to 5 was sandwiched between two glass plates, and phase morphology was observed with a polarizing microscope. As a result, the following phase transitions in Table 1 were confirmed.

Example 6 (Use Example 1) In order to see the effects of the liquid crystal composition according to the present invention, first, the following four compounds were mixed to prepare a mother liquid crystal composition.

The mother liquid crystal composition was sandwiched between two glass plates, and phase morphology was observed with a polarizing microscope. As a result, the following phase transition was confirmed.

A liquid crystal composition was prepared by mixing 10% by weight of the compounds synthesized in Examples 1 and 3 with 90% by weight of the mother liquid crystal composition, and the phase transition temperature was similarly determined using a polarizing microscope. It was measured.

Further, the liquid crystal composition was applied to a 2 μm-thick cell having a glass transparent electrode subjected to a parallel alignment treatment by applying a polyimide as an alignment agent and rubbing the surface thereof to form a liquid crystal display element. When a 15 V electric field (60 Hz rectangular wave alternating current) was applied, a clear change in transmitted light intensity was observed. The spontaneous polarization (Ps) was measured using the triangular wave method, and the response speed (τ) at 30 ° C. was measured. The results are shown in Table 2 below.

(Effects of the Invention) As exemplified above, by using the optically active ester compound of the present invention as a component of the liquid crystal composition, to impart spontaneous polarization to the SmC phase of the mother liquid crystal having an SmC phase,
It can be a chiral smectic C phase. At that time, the temperature range of the SmC ^* phase can be made wider than that of the original SmC phase, and the compound is useful as one component of an excellent ferroelectric liquid crystal composition.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C09K 19/34 C09K 19/34 // G02F 1/13 500 G02F 1/13 500 C07M 7:00

Claims (2)

(57) [Claims] 1. An optically active ester compound represented by the following general formula (I). (Wherein R represents an alkyl group having 1 to 18 carbon atoms or an alkoxy group having 1 to 18 carbon atoms, Z represents a direct bond, -COO
-Or -OCO-, Each independently represents 1,4-phenylene or 2,5-pyrimidinylene; a and b represent 0 or 1;
Represents 1 or 2, a + b + c = 3, and * represents an asymmetric carbon atom. ) 2. A ferroelectric liquid crystal composition containing at least one kind of an optically active ester compound represented by the following general formula (I). (Wherein R represents an alkyl group having 1 to 18 carbon atoms or an alkoxy group having 1 to 18 carbon atoms, Z represents a direct bond, -COO
-Or -OCO-, Each independently represents 1,4-phenylene or 2,5-pyrimidinylene; a and b represent 0 or 1;
Represents 1 or 2, a + b + c = 3, and * represents an asymmetric carbon atom. )