JP2575782B2 - New optically active ester compound - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a novel optically active ester compound useful as a liquid crystal material and a method for producing the same.

(Prior art)

At present, liquid crystal materials are widely used for display elements, but most of these liquid crystal display elements are of a TN (Twisted Nematic) type using a nematic liquid crystal. However, this method has a slow response speed, at most a few milliseconds.
There is a drawback that only a response speed of the order of

For this reason, various types of liquid crystal display methods based on other principles have been tried in place of the TN type display method. One of them is a display method using a ferroelectric liquid crystal (NAClarks et al .; Applied Phys.
tt.36,899 (1980)). This method utilizes a ferroelectric chiral smectic phase, particularly a chiral smectic C phase, and has attracted attention for high-speed optical switching. Some of such ferroelectric liquid crystal materials are already known (for example, JP-A-60-32748).
Nothing shows satisfactory properties.

〔Purpose〕

An object of the present invention is to provide a novel optically active ester compound having sufficiently satisfactory properties, such as a high response speed and being chemically stable, as a liquid crystal material suitable for an optical switching method, and a method for producing the same. is there.

〔Constitution〕

The novel optically active ester compound of the present invention has the general formula (Where R represents an alkoxy group having 20 or less carbon atoms, n represents an integer of 1 or 2, and * represents an asymmetric carbon atom).

The method for producing the optically active ester compound represented by the general formula (I) of the present invention is represented by the formula (II): (Where * represents an asymmetric carbon atom) and p-hydroxybenzoic acid-2- (4-methylcyclohexyl-1) propyl ester represented by the general formula (II)
I) (Wherein R is an alkoxy group having 20 or less carbon atoms, n is an integer of 1 or 2, X represents a hydroxy group or a halogen atom), or a carboxylic acid halide or a carboxylic acid halide thereof. Is what you do. Formula II
Is also a novel compound.

The greatest feature of the ester compound of the present invention represented by the general formula (I) is that it contains a cyclohexyl group having an asymmetric carbon. The conventional ferroelectric liquid crystal compound also contains asymmetric carbon, but in the case of the conventional compound, the asymmetric carbon source is an alkyl group such as active amyl alcohol. By using a cyclohexyl group as the asymmetric carbon source as in the compound of the present invention, 1) the viscosity is reduced, and 2) the spontaneous polarization is increased due to the steric effect of the asymmetric source. As a result, the response speed is dramatically improved. be able to.

Specific examples of the optically active ester compound of the above general formula (I) are shown in the following table in relation to the following general formula.

These compounds of the general formula (I) are generally of the formula (II)
Hydroxybenzoic acid-2- (4-methylcyclohexyl-1) propyl ester is reacted with a carboxylic acid of the general formula (III) at room temperature in a solvent using a condensing agent such as N, N'-dicyclohexylcarbodiimide. Alternatively, it is obtained by reacting a carboxylic acid halide of the general formula (III) with a base catalyst such as pyridine in a solvent at room temperature. As the solvent, toluene, methylene chloride, 1,2-dichloroethane or the like is used. Note that the formula (I
The ratio of the compound of the formula (I) to the compound of the formula (III) may be a stoichiometric amount.

The compound of the formula (II) is, for example, according to the following reaction formula:
4-benzyloxybenzoic acid chloride (IV) and (R, R)
Reaction with 2- (4-methyl-3-cyclohexenyl-1) propanol (V) in the presence of a basic catalyst such as pyridine to give optically active benzyloxybenzoic acid-2-
(4-Methyl-3-cyclohexenyl-1) propyl ester (VI), which is then obtained by reduction in the presence of a reducing catalyst such as Pd-carbon.

The optically active ester compound represented by the general formula (I) of the present invention exhibits excellent performance as a ferroelectric liquid crystal material,
It shows large spontaneous polarization at low viscosity and is chemically stable.

Although the novel optically active ester compound represented by the general formula (I) of the present invention can be used alone as a ferroelectric liquid crystal material, it is mixed with another liquid crystal material, particularly a ferroelectric liquid crystal material to improve the performance. Things. The liquid crystal composition containing the compound of the present invention is used not only for display but also for various electro-optical devices such as an electro-optical shutter, an electro-optical stop, an optical modulator, an optical communication optical path switch, a memory, and a variable focal length lens. It can be suitably used in the field of optoelectronics.

Among other liquid crystal compounds that can be used in combination with the compound of the present invention,
Table 2 shows examples of ferroelectric chiral smectic phases.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. The value of the phase transition temperature in the examples slightly varies depending on the measurement method and the purity of the compound.

Example 1 Preparation of Compound No. 6 {optically active Pn-decyloxybenzoic acid-P '-[2- (4-methylcyclohexyl-1) propoxycarbonyl] phenyl ester} A. Optically active P-benzyloxybenzoic acid Production of 2- (4-methyl-3-cyclohexenyl-1) propyl ester (VI) 15.4 g of commercially available (R, R) 2- (4-methyl-3-cyclohexenyl-1) propanol (V) ( 0.1 mol) was dissolved in 100 ml of pyridine, and 27.1 g (0.11 mol) of P-benzyloxybenzoic acid chloride (IV) was added thereto while cooling, and the mixture was stirred and reacted at 50 to 60 ° C. for 2 hours. After the completion of the reaction, put 150 ml of water and 150 ml of toluene into this, and stir well,
The separated toluene layer was washed with 6N-HCl and subsequently with water until neutral. After the toluene layer was dried over anhydrous magnesium sulfate, the toluene was distilled off, and then the residue was subjected to silica gel column chromatography using toluene as a developing solvent to obtain 31.4 g of a crude target product (VI).

B. Production of optically active P-hydroxybenzoic acid-2- (4-methylcyclohexyl-1) propyl ester (II) The P-benzyloxybenzoic acid-2- (4
31.4 g of -methyl-3-cyclohexenyl-1) propyl ester was dissolved in a mixed solvent of 100 ml of 1,4-dioxane and 100 ml of ethanol, and subjected to catalytic hydrogenation at room temperature in the presence of 4.7 g of a Pd-carbon catalyst. Two times moles of hydrogen were required. After completion of the reaction, Pd-carbon was removed by filtration, the solvent was distilled off, and the residue was recrystallized from toluene to obtain 16.7 g of a pure target product (II).

Properties of compound (II) Melting point 149.5-150.0 ° C Optical rotation [α] ^D : (-) 1.08 ゜ (chloroform) Elemental analysis Calculated value C (%) 73.82 73.88 H (%) 8.87 8.75 , Confirmed by infrared absorption spectrum. FIG. 1 shows the infrared absorption spectrum.

C. Production of compound (No. 6) 2.2 g (0.00 g) of P-hydroxybenzoic acid-2- (4-methylcyclohexyl-1) propyl ester obtained in B above
8 mol) was dissolved in 50 ml of pyridine, and while cooling, 3.0 g (0.01 mol) of Pn-decyloxybenzoic acid chloride was added thereto. The mixture was stirred at room temperature for 5 hours, allowed to react overnight, and then left standing overnight. , And 200 ml of toluene, and the mixture was thoroughly stirred. The separated toluene layer was washed with 6N-HCl, and then washed with water until neutral. The toluene layer was dried over anhydrous magnesium sulfate, and then toluene was distilled off. Then, the residue was subjected to silica gel chromatography using toluene as a developing solvent, and the obtained crude product was recrystallized three times with ethanol to obtain pure toluene. 1.6 g of the desired product [compound (No. 6)]
I got The structure was confirmed by infrared absorption spectrum.

Example 2 Compound (No. 4) {optically active Pn-octyloxybenzoic acid-P '-[2- (4-methylcyclohexyl-
1) Production of propoxycarbonyl] phenyl ester {P-hydroxybenzoic acid-2- (4-methylcyclohexyl-1) propyl ester 1.7 g (0.00 g) obtained in B above
6 mol), 1.7 g (0.0066 mol) of P-octyloxybenzoic acid, 1.4 g of N, N-dicyclohexylcarbodiimide and 0.2 g of 4-dimethylaminopyridine in 100 ml of methylene chloride
The mixture is stirred at room temperature for 5 hours at room temperature and left overnight. The crystals were filtered, the residue obtained by distilling off methylene chloride was subjected to silica gel column chromatography using toluene as a developing solvent, and the obtained crude target compound was recrystallized three times from ethanol to obtain a pure target compound [compound (No. .4)] 0.6 g was obtained. The structure was confirmed by an infrared absorption spectrum as in Example 1.

Example 3 Compound (No. 2) ｛optically active Pn-hexyloxybenzoic acid P ′-[2- (4-methylcyclohexyl-1)
Production of propoxycarbonyl] phenyl ester {pure octyloxybenzoic acid instead of 1.7 g, P-hexyloxybenzoic acid 1.5 g (0.0066 mol) was used in the same manner as in Example 2 except that pure target product 1.7 was used. I got The structure was confirmed by an infrared absorption spectrum as in Example 1.

Example 4 Production of Compound (No. 19) {Optically Active P-hexadecyloxy-P′-biphenylcarboxylic acid-P ″-[2- (4-methylcyclohexyl-1) propoxycarbonyl] phenyl ester} 1.7 g (0.00%) of the obtained P-hydroxybenzoic acid-2- (4-methylcyclohexyl-1) propyl ester
6 mol), 2.9 g (0.0066 mol) of Pn-hexadecyloxy-P'-biphenylcarboxylic acid, 1.4 g of N, N'-dicyclohexylcarbodiimide and 0.2 g of 4-dimethylaminopyridine at room temperature in 100 ml of methylene chloride. Stir for hours and leave overnight. The crystals were filtered, and the residue obtained by distilling off methylene chloride was subjected to silica gel column chromatography using toluene as a developing solvent. The obtained crude target product was crystallized three times from a mixed solvent of ethanol-ethyl acetate to obtain a pure target product [ 2.3 g of compound (No. 19) was obtained. The structure was confirmed by infrared absorption spectrum.
FIG. 2 shows the infrared absorption spectrum.

Example 5 Compound (No. 18) Optically active ΔPn-tetradecyloxy-P′-biphenylcarboxylic acid-P ″-[2- (4
-Methylcyclohexyl-1) propoxycarbonyl]
Preparation of Pn-hexadecyloxy-P'-biphenylcarboxylic acid Instead of 2.9 g of Pn-tetradecyloxy-
Except that 2.7 g (0.0066 mol) of P'-biphenylcarboxylic acid was used, 3.0 g of the pure desired product was obtained in the same manner as in Example 4.
Its structure was confirmed by infrared absorption spectrum.

Example 6 Preparation of compound (No. 17) {optically active Pn-dodecyl ishi-P′-biphenylcarboxylic acid-P ″-[2- (4-methylcyclohexyl-1) propoxycarbonyl] phenyl ester} Instead of 2.9 g of n-hexadecyloxy-P'-biphenylcarboxylic acid, Pn-dodecyloxy-P'-
Except that 2.5 g (0.0066 mol) of biphenylcarboxylic acid was used, 2.6 g of the pure desired product was obtained in the same manner as in Example 4. The structure was confirmed by infrared absorption spectrum.

Example 7 Compound (No. 16) {optically active Pn-decyloxy-
Preparation of P'-biphenylcarboxylic acid-P "-[2- (4-methylcyclohexyl-1) propoxycarbonyl] phenyl ester {P-n-hexadecyloxy-P'-biphenylcarboxylic acid Except that 2.4 g (0.0066 mol) of n-decyloxy-P'-biphenylcarboxylic acid was used, 3.1 g of a pure target product was obtained in the same manner as in Example 4. The structure was confirmed by an infrared absorption spectrum. .

Example 8 Compound (No. 15) {optically active Pn-nonyloxy-
Preparation of P'-biphenylcarboxylic acid-P "-[2- (4-methylcyclohexyl-1) propoxycarbonyl] phenyl ester {P-n-hexadecyloxy-P'-biphenylcarboxylic acid Except that 2.3 g (0.0066 mol) of n-nonyloxy-P'-biphenylcarboxylic acid was used, 2.3 g of a pure target product was obtained in the same manner as in Example 4. The structure was confirmed by an infrared absorption spectrum. .

Example 9 Production of Compound (No. 14) {Optically Active Pn-octyloxy-P'-biphenylcarboxylic acid-P "-[2- (4-methylcyclohexyl-1) propoxycarbonyl] phenyl ester} Instead of 2.9 g of n-hexadecyloxy-P'-biphenylcarboxylic acid, Pn-octyloxy-P'-
Except that 2.2 g (0.0066 mol) of biphenylcarboxylic acid was used, 2.4 g of the pure desired product was obtained in the same manner as in Example 4. The structure was confirmed by infrared absorption spectrum.

Example 10 Preparation of compound (No. 13) {optically active Pn-heptyloxy-P'-biphenylcarboxylic acid-P ″-[2- (4-methylcyclohexyl-1) propoxycarbonyl] phenyl ester} Instead of 2.9 g of n-hexadecyloxy-P'-biphenylcarboxylic acid, Pn-heptyloxy-P'-
Except that 2.1 g (0.0066 mol) of biphenylcarboxylic acid was used, 2.4 g of the pure desired product was obtained in the same manner as in Example 4. The structure was confirmed by infrared absorption spectrum.

Example 11 Preparation of compound (No. 12) {optically active Pn-hexyloxy-P'-biphenylcarboxylic acid-P ″-[2- (4-methylcyclohexyl-1) propoxycarbonyl] phenyl ester} Instead of 2.9 g of n-hexadecyloxy-P'-biphenylcarboxylic acid, Pn-hexyloxy-P'-
Except that 1.8 g (0.0066 mol) of biphenylcarboxylic acid was used, 1.8 g of a pure target product was obtained in the same manner as in Example 4. Its structure was confirmed by infrared absorption spectrum.

The melting point and elemental analysis results of the compound obtained as described above are shown in the table below.

Table 4 shows the phase transition temperatures of the above compounds. Further, with respect to Compound Nos. 16 and 17, the value of the spontaneous polarization (n
c / cm ² ), 7.0 (70 ° C)) and 7.8 (70
° C).

[Example of use] Example of use 1 After coating the surface of each electrode with polyvinyl alcohol (PVA), two transparent electrodes whose surfaces are rubbed and subjected to a parallel alignment treatment are opposed at an interval of 3 µm with the PVA film inside. After the optically active ester compound [compound (No. 16)] prepared in Example 7 was injected into the formed cell,
When placed between two orthogonal polarizers to form a liquid crystal display element and a voltage of 20 V was applied between the electrodes, the liquid crystal display was clear, had very good contrast, and had a fast response speed (about 100 μse
c) Switching operation was observed. The spontaneous polarization of this liquid crystal was 7.0 nc / cm ² (70 ° C.).

Use Example 2 A composition was prepared by mixing the compound (No. 6) prepared in Example 1 with 48.5% by weight of 4-octyloxybenzoic acid 4'-n-hexyloxyphenyl ester. The phase transition points of this composition were as follows.

SmC ^* : Ferroelectric smectic C phase SmA: Smectic A phase Ch: Cholesteric phase I: Isotropic liquid [Effect] Of the optically active ester compounds of the present invention represented by the general formula (I), n = 2 Most of the carrier is a chiral smectic C phase, and the magnitude of its spontaneous polarization (Ps) is a known chiral smectic C phase compound.
For example, 4- (4'-n-decyloxybenzylideneamino) cinnamic acid-2-methylbutyl ester (J. Physique
36 , L-69 (1975), these compounds are particularly excellent ferroelectric liquid crystal materials because they are larger than Ps (about 3 nc / cm ² ).

Further, as shown in Table 3, n = 1 in the general formula (I).
Although the compound having a low melting point is preferable, as shown in Table 4, the chiral smectic C phase is not observed by itself. However, as shown in Use Example 2, when this compound alone is mixed with a compound showing an SmC phase, it shows a ferroelectric smectic C phase, so it can be said that the compound has potential ferroelectricity.

Further, since the compound of the general formula (I) has an optically active carbon atom, it has an ability to induce a twisted structure by adding the compound to a nematic liquid crystal. A nematic liquid crystal having a twisted structure, that is, a chiral nematic liquid crystal, is a so-called reverse domain of a TN type display device.
The compound of the general formula (I) can be used as an inhibitor of reverse domain formation since it does not form in).

Further, since the compound of the general formula (I) of the present invention has a characteristic of exhibiting a chiral smectic C phase in a wide temperature range, it can be an effective blend material for obtaining a ferroelectric composition.

[Brief description of the drawings]

FIG. 1 is an infrared absorption spectrum of the optically active P-hydroxybenzoic acid-2- (4-methylcyclohexyl-1) propyl ester obtained in B of Example 1, and FIG. 2 is obtained in Example 4. FIG. 3 is an infrared absorption spectrum of optically active Pn-tetradecyloxy-P′-biphenylcarboxylic acid-P ″-[2- (4-methylcyclohexyl-1) propoxycarbonyl] phenyl ester.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location // G02F 1/13 500 G02F 1/13 500 C07M 7:00

Claims (4)

(57) [Claims] (1) General formula (Where R represents an alkoxy group having 20 or less carbon atoms, n represents an integer of 1 or 2, and * represents an asymmetric carbon atom). (2) (However, * represents an asymmetric carbon atom.) 2- (4-methylcyclohexyl-1) propyl ester of p-hydroxybenzoic acid represented by the formula: 3. The general formula (Where * represents an asymmetric carbon atom) and p-hydroxybenzoic acid-2- (4-methylcyclohexyl-1) propyl ester represented by the general formula: (Wherein R is an alkoxy group having 20 or less carbon atoms, n is an integer of 1 or 2, X represents a hydroxy group or a halogen atom), or a carboxylic acid halide or a carboxylic acid halide thereof. General formula (Where R represents an alkoxy group having 20 or less carbon atoms, n represents an integer of 1 or 2, and * represents an asymmetric carbon atom). 4. General formula (Where R represents an alkoxy group having 20 or less carbon atoms, n represents an integer of 1 or 2, and * represents an asymmetric carbon atom).