JPH0784414B2 - Optically active ester compound - Google Patents

Description

The present invention relates to an optically active alkyl or alkoxy benzoic acid alkoxyphenyl ester compound useful as a ferroelectric liquid crystal compound.

Currently, the widely used liquid crystal display devices are twisted nematic (TN type) and dynamic scattering type (DS type). These are displays by a nematic liquid crystal cell whose main component is nematic liquid crystal. One of the disadvantages of conventional nematic liquid crystal cells is the fact that the response speed is slow and only a response speed on the order of a few milliseconds can be obtained, which is one of the reasons for narrowing the range of application of nematic liquid crystal cells. Has become. However, it has recently been found that a higher 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. As the liquid crystal exhibiting ferroelectricity, that is, the ferroelectric liquid crystal, for example, 4- (4
-N-decyloxybenzylideneamino) cinnamic acid-2
-Methylbutyl ester (hereinafter abbreviated as DOBAMBC) is known, and is characterized by exhibiting ferroelectricity in its chiral smectic phase (hereinafter abbreviated as Sc ^* phase).

In recent years, with the discovery of high-speed response on the order of microseconds in thin film cells of DOBAMBC, ferroelectric liquid crystal utilizes its high-speed response not only for displays such as liquid crystal TVs, but also for optical printers. It is attracting attention as a material that can be used as a material for optoelectronic-related elements such as heads, optical Fourier transform elements, and light valves.

However, since DOBAMBC contains a Schiff base, it is chemically unstable and has not yet been put to practical use.

An object of the present invention is to provide a compound having a novel optical activity which can be used in the above applications.

That is, the present invention provides a compound represented by the following general formula.

(In the formula, R ₁ represents a hydrogen atom or a linear alkyl group having 1 to 12 carbon atoms, R ₂ represents a linear alkyl group having 1 to 18 carbon atoms, n represents 0 or 1, and * Represents an asymmetric carbon atom.) Hereinafter, the present invention having the above-mentioned gist will be described in more detail.

The compound represented by the above general formula is easily synthesized by a well-known esterification reaction such as reacting benzoic acid having an optically active alkoxy substituent at the 4-position with 4-n-alkyl or alkoxyphenol. can do.

The compound represented by the above general formula of the present invention thus obtained is a Sc ^* phase and / or a chiral nematic phase (hereinafter referred to as N ^*
Can be used alone as a liquid crystal material, or can be mixed with another liquid crystal compound and used as one component of a liquid crystal composition.

Next, the present invention will be described with reference to examples. However, the present invention is not limited to these examples.

Example 1 (R) -4-n-hexyloxybenzoic acid-4- (6'-
Synthesis of chloro-4′-methylhexyloxy) phenyl ester [α] _D = −3.76 ° (27 ° C., C = 2, CHCl ₃ solution) was synthesized from (R) -6-chloro-4-methylhexanol. α] _D = + 2.02 ° (24 ° C, C = 1, CHCl ₃ solution)
(R) -4- (6'-chloro-4'-methylhexyloxy) phenol 0.97 g, 4-n-hexyloxybenzoic acid 0.98 g, N, N'-dicyclohexylcarbodiimide 0.91
g, 4-pyrrolidinopyridine 0.09 g and dichloromethane 20
ml was taken and stirred at room temperature for 5 hours. The precipitated dicyclohexylurea was filtered off and the filtrate was desolvated. The obtained crude product was purified by using a silica gel column with n-hexane / diethyl ether (85/15) as a developing solvent and then recrystallized from methanol to obtain the desired (R) -4-n-hexyloxybenzoic acid. -4- (6'-Chloro-4'-methylhexyloxy) phenyl ester was obtained as colorless needle crystals.

As a result of infrared spectroscopic analysis, the obtained product had the following characteristic absorptions and was confirmed to be the target product.

3070cm ^-1 (vw), 2940cm ^-1 (s), 2875cm ^-1 (m), 1730cm ^-1 (s), 1610cm ^-1 (s), 1515cm ^-1 (s), 1470cm ^-1 (m), 1390cm ^{-1 (w), 1315cm -1 (} w), 1255cm -1 (vs), 1200cm -1 (s), 1170cm -1 (s), 1105cm -1 (w), also 1075cm ^-1 (s), obtained The optical rotation of the obtained product is shown below.

[Α] _D = + 1.70 ° (26 ° C, C = 1, CHCl ₃ solution) This compound was sandwiched between two glass plates and the phase morphology was observed with a polarizing microscope. The following phase transitions were confirmed. did.

Example 2 Synthesis of (4R) -4-n-octylbenzoic acid-4- (6′-chloro-4′-methyloctoxy) phenyl ester [α] _D = + 0.75 ° (28 ° C., C = 1) , CHCl ₃ solution) (4
(4R) -4- (6′-chloro-4 ′) of [α] _D = + 5.82 ° (26 ° C., C = 1, CHCl ₃ solution) synthesized from (R) -6-chloro-4-methyloctanol. A reaction similar to that in Example 1 was performed except that -methyloctoxy) phenol and 4-n-octylbenzoic acid were used. The obtained crude product was purified using a silica gel column with n-hexane / diethyl ether (90/10) as a developing solvent, and the desired (4
R) -4-n-octylbenzoic acid-4- (6′-chloro-4′-methyloctoxy) phenyl ester was obtained.

As a result of infrared spectroscopic analysis, the obtained product had the following characteristic absorptions and was confirmed to be the target product.

3050cm ^-1 (vw), 2940cm ^-1 (s), 2870cm ^-1 (m), 1735cm ^-1 (s), 1615cm ^-1 (m), 1505cm ^-1 (s), 1465cm ^-1 (m), 1420cm ^{-1 (w), 1380cm -1 (} w), 1270cm -1 (s), 1245cm -1 (s), 1200cm -1 (s), 1180cm -1 (m), 1105cm -1 (w), 1075cm - ^{1 (s), 1020cm -1 (} m), 930cm -1 (vw), 905cm -1 (vw), 875cm -1 (w), 825cm -1 (vw), 760cm -1 (w), 700cm -1 ^{(w), 665cm -1 (vw} ), 635cm -1 (vw), 605cm -1 (vw), 580cm -1 (vw), also 520cm ^-1 (w), the optical rotation of the product obtained following Shown in.

[Α] _D = + 4.15 ° (27 ° C, C = 1, CHCl ₃ solution) This compound was sandwiched between two glass plates, and the phase morphology was observed with a polarizing microscope. The following phase transitions were confirmed. did.

Example 3 Synthesis of (4R) -4-n-octoxybenzoic acid-4- (6′-chloro-4′-methyldecyloxy) phenyl ester [α] _D = −1.95 ° (26 ° C., C = 1, CHCl ₃ solution) (4
R) -6-chloro-4-methyldecanol synthesized from [α] _D = + 2.00 ° (26 ° C., C = 1, CHCl ₃ solution) (4
R) -4- (6'-chloro-4'-methyldecyloxy)
The desired (4R) -4-n- was prepared by the same procedure as in Example 2 except that phenol and 4-n-octoxybenzoic acid were used.
Octoxybenzoic acid-4- (6'-chloro-4'-methyldecyloxy) phenyl ester was obtained.

As a result of infrared spectroscopic analysis, the obtained product had the following characteristic absorptions and was confirmed to be the target product.

3070cm ^-1 (vw), 2940cm ^-1 (vs), 2875cm ^-1 (s), 1735cm ^-1 (vs), 1610cm ^-1 (m), 1510cm ^-1 (m), 1465cm ^-1 (m), 1380cm ^{-1 (w), 1315cm -1 (} vw), 1300cm -1 (w), 1270cm -1 (s), 1250cm -1 (s), 1200cm -1 (s), 1170cm -1 (m), 1105cm - ¹ (w), 1075 cm ^-1 (s) The optical rotation of the obtained product is shown below.

[Α] _D = + 0.75 ° (27 ° C, C = 1, CHCl ₃ solution) This compound was subjected to orientation treatment by rubbing to give a thickness of 2
After injecting into a glass transparent electrode cell of μm, it was heated to 90 ° C. to obtain an isotropic liquid.

This liquid crystal cell was cooled under a crossed Nicols while applying a rectangular wave of ± 15 V and 1 Hz, and the phase morphology was observed with a polarization microscope to confirm the following phase transitions.

Claims (1)

[Claims] 1. An optically active ester compound represented by the following general formula. (In the formula, R ₁ represents a hydrogen atom or a linear alkyl group having 1 to 12 carbon atoms, R ₂ represents a linear alkyl group having 1 to 18 carbon atoms, n represents 0 or 1, and * Represents an asymmetric carbon atom.)