JPH0796531B2 - Optically active compound - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel optically active compound.

More specifically, it relates to an optically active compound useful as an intermediate for a novel optically active liquid crystal compound.

[Conventional technology]

At present, various liquid crystal display devices have been put into practical use. Above all, TN (Twisted Nematic) using nematic liquid crystal
The type display method has excellent performance of extremely low power consumption and is widely used. However, this display method has a drawback that the response speed is slow.

With the recent progress in industrial technology, there is a strong demand for high-speed response in liquid crystal display devices, and various attempts have been made by improving liquid crystal materials to meet such demands. In order to meet the above demand, a display device utilizing an optical switching phenomenon of a ferroelectric liquid crystal using an optically active smectic liquid crystal has already been proposed (Appl. Phys. Lett., 36 899 ( 1980))).

As a representative of known ferroelectric liquid crystals, there is one shown in Table 1.

[Problems to be solved by the invention]

The known ferroelectric liquid crystal compounds shown in Table 1 have unstable elements such as isomerization by light within a short time and hydrolysis by water so that the liquid crystal phase is not exhibited. Is not preferable.

The object of the present invention is to have photochemical and chemical stability without such unstable elements, and To provide a novel compound useful as an intermediate of a ferroelectric liquid crystal having

[Means for solving problems]

The present inventors have arrived at the present invention by searching various compounds in order to solve the above problems.

That is, the invention has the general formula (I) (In the formula, m is an integer of 1 to 3, R represents an alkyl group having 410 carbon atoms, and * represents an asymmetric carbon atom.). The compound of formula (I) can be produced by various methods, but typically, it can be produced by the following synthetic route.

(However, m, R, and * are the same as above, and Bz represents a benzyl group.) That is, 2,6-hydroxynaphthalenecarboxylic acid (a) is benzylated to form compound (b), and then thionyl chloride is added. , Oxalic acid chloride and the like to obtain the acid chloride derivative (c). Then, the ester form (d) is obtained by reacting (c) with various optically active secondary alcohols.
And Then, it can be debenzylated with hydrogen in the presence of palladium / carbon to produce compound (I). The 2,6-hydroxynaphthalenecarboxylic acid used in the production of the compound (I) of the present invention is, for example,
Of Chemical Society (J.Chem.Soc., 1954, 678)
It is a known substance as described in.

Examples of useful optically active alcohols as raw materials include, for example, optically active 2-methylhexanol, optically active 2-methyloctanol, optically active 2-methylnonanol, optically active 2-methyldecanol, optically active 2-
Methyl undecanol, optically active 2-methyl dodecanol, optically active 2-methyl tridecanol, optically active 3-
Heptanol, optically active 3-methyloctanol, optically active 3,7-dimethyloctanol, optically active 3-methylnonanol, optically active 3-methyldecanol, optically active 4-methyloctanol, optically active 4-methylnonanol, optical Mention may be made of active 4-methyldecanol.

Among these, preferably, optically active 2-methylhexanol, optically active 2-methyloctanol, optically active 3-methylheptanol, optically active 3-methyloctanol,
Optically active 3,7-dimethyloctanol, optically active 4-methyloctanol, more preferably optically active 3,7
-Dimethyloctanol.

Moreover, the absolute configuration of the optically active alcohol is (R) and (S).
It goes without saying that both bodies can be used.

In general, a liquid crystal compound has a rod-like structure composed of a nucleus portion including a benzene ring, a heterocyclic ring, a cyclohexane ring and the like, and an alkyl chain and the like.

It is well known that those having an alkyl chain having a certain number of carbon atoms or more tend to show a smectic phase.

That is, the compound represented by the general formula (I) can be prepared by, for example, alkylcarboxylic acid, alkoxycarboxylic acid, 4-alkylbenzoic acid, 4-alkoxybenzoic acid, 4-alkylcarbonyloxybenzoic acid, 4-alkoxycarbonylbenzoic acid, 4 -Alkoxycarbonyloxybenzoic acid, 6-
Alkyl-naphthalene-2-carboxylic acid, 6-alkoxy-naphthalene-2-carboxylic acid, 6-alkylcarbonyloxy-naphthalene-2-carboxylic acid, 6-alkoxycarbonyl-naphthalene-2-carboxylic acid, 6-alkoxycarbonyloxy -Naphthalene-2-carboxylic acid, 4- (4'-alkylphenyl) benzoic acid, 4-
(4'-alkoxyphenyl) benzoic acid, 4- (4'-
Alkylcarbonyloxyphenyl) benzoic acid, 4-
(4'-alkoxycarbonylphenyl) benzoic acid, 4
-(4'-alkoxycarbonyloxyphenyl) benzoic acid, trans-4- (4'-alkylphenyl) cyclohexylcarboxylic acid, trans-4- (4'-alkoxyphenyl) cyclohexylcarboxylic acid, trans-
4- (4'-alkylcarbonyloxyphenyl) cyclohexylcarboxylic acid, trans-4- (4'-alkoxycarbonylphenyl) cyclohexylcarboxylic acid,
Trans-4- (4'-alkoxycarbonyloxyphenyl) cyclohexylcarboxylic acid, 4- (trans-
4'-alkylcyclohexyl) benzoic acid, 4- (5 '
-Alkylpyrimidin-2'-yl) benzoic acid, 4-
(5′-Alkoxypyrimidin-2′-yl) benzoic acid, 4- (trans-5′-alkyl-1 ′, 3′-dioxane-2′-yl) benzoic acid, 4- (trans-5 ′)
-Alkyl-1 ', 3'-dithiaoxan-2'-yl)
Benzoic acid, 4- (trans-5'-alkyl-1 ', 3'
Halogen atom in benzene ring or naphthalene ring of dithian-2'-yl) benzoic acid, 4- (5'-alkyl-1 ', 3', 2'-dioxaborinan-2'-yl) benzoic acid or these compounds A very useful ferroelectric liquid crystal can be obtained by reacting with a derivative in which a cyano group, a nitro group, a methyl group or an ethyl group is substituted.

For example, a compound represented by the general formula (II) produced from the compound (I) of the present invention and 4-alkoxybenzoic acid (In the formula, R ₁ is an alkyl group having 1 to 20 carbon atoms, n is an integer of 1 to 3, R ₂ is an alkyl group having 4 to 10 carbon atoms, and * indicates an asymmetric carbon atom.) , Chiral smectic as shown in the specific examples in Table 2. It is important as a constituent component in preparing a ferroelectric liquid crystal mixture having a C phase and operating near room temperature.

In Table 2, C is the crystalline phase, SC ^* is the chiral smectic C.
A phase, SA is a smectic A phase, and I is an isotropic liquid, and the mark and the number on the right side of each phase indicate the transition temperature from that phase to the phase on the right side.

The value in the parentheses is the monotropic phase transition temperature.

[Work]

The compounds of the present invention are very useful as intermediates in the production of optically active liquid crystal compounds. The compound of the present invention has an optically active group in the molecule and is particularly useful as an intermediate in the production of ferroelectric liquid crystal and chiral nematic liquid crystal.

Further, by introducing the compound of the present invention into a polymer liquid crystal, a polymer liquid crystal exhibiting an electro-optical effect can be produced.

〔Example〕

Hereinafter, the compounds of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 (s) -6-hydroxynaphthalene-2-carboxylic acid-
3 ', 7'-dimethyl octyl ester ((m = 2, R = in I) wherein _{- (CH 2) 2 CH (} CH 3)
Production of compound ₂ )) (i) Production of 6-benzyloxynaphthalene-2-carboxylic acid.

100 g of 2,6-hydroxynaphthalenecarboxylic acid and 70 g of 85% potassium hydroxide were dissolved in 100 ml of water and 700 ml of ethanol, 110 g of benzyl bromide was added, and the mixture was heated under reflux for 8 hours. Then add another 35g of potassium hydroxide, 5
Heating under reflux was continued for hours.

After cooling to room temperature, it was acidified with concentrated hydrochloric acid and the precipitated solid was filtered off. Wash with water, ethanol, and benzene in that order,
I got the object. This was used in the next reaction without further purification.

(Ii) Production of 6-benzyloxynaphthalene-2-carboxylic acid chloride Compound 6-benzyloxynaphthalene-2 obtained in (i)
-65 g of carboxylic acid was heated under reflux with 30 ml of thionyl chloride in 50 ml of toluene for 3 hours, and excess thionyl chloride and toluene were distilled off under reduced pressure to obtain an acid chloride. This crude product was used in the next reaction without purification.

(Iii) (s) -6-benzyloxynaphthalene-2-
Production of carboxylic acid-3 ', 7'-dimethyloctyl ester The acid chloride obtained in (ii) was dissolved in 100 ml of toluene, and 38 g of (s) -3,7-dimethyloctanol was dissolved in 30 ml of pyridine. The solution was added and left at room temperature for 8 hours. After the precipitated pyridine hydrochloride was filtered off, the organic layer was washed with 2N.
-Washing with hydrochloric acid, further washing with 2N-sodium hydroxide aqueous solution, and further washing with water until it became neutral.

The organic layer was separated, toluene was distilled off under reduced pressure, and the residue was recrystallized from ethanol to obtain 70 g of the desired product as colorless plate crystals.

Melting point 51.5-53.0 ° C. (iv) 70 g of (s) -6-benzyloxynaphthalene-2-carboxylic acid-3 ′, 7′-dimethyloctyl ester obtained in (iii) was dissolved in 200 ml of ethanol to obtain 5% palladium. / Hydrogenated at 40 ° C. in the presence of 4 g carbon.

After the palladium / carbon was filtered off, the solvent was evaporated under reduced pressure, and the residue was recrystallized from ethanol-n-hexane to give the desired (s) -6-hydroxynaphthalene-2- as colorless needle crystals. 50 g of carboxylic acid-3 ', 7'-dimethyloctyl ester was obtained.

Melting point 86.5-88.2 ° C. Elemental analysis values of this compound were in good agreement with theoretical values as shown in Table 3.

Examples 2 to 15 (iii) of Example 1 except that various optically active alcohols were used in place of (s) -3,7-dimethyloctanol in (iii) of Example 1. Various optically active 6-benzyloxynaphthalene-2-carboxylic acid-alkyl esters were prepared according to the method described in 1.

Furthermore, in (iv) of Example 1, various optically active 6-benzyloxynaphthalene-2-carboxylic acids were used instead of (S) -6-benzyloxynaphthalene-2-carboxylic acid-3 ', 7'-dimethyloctyl ester. -Various optically active 6-hydroxynaphthalene-2 according to the method described in (iv) of Example 1 except that the alkyl ester was used.
-Carboxylic acid-alkyl ester was prepared.

The elemental analysis values of these compounds were in good agreement with the theoretical values as shown in Table 3.

〔The invention's effect〕

The compound produced by using the compound of the present invention as an intermediate is a very excellent ferroelectric liquid crystal and is very stable photochemically and chemically.

Claims (1)

[Claims] 1. A general formula (I) (In the formula, m is an integer of 1 to 3, R is an alkyl group having 4 to 10 carbon atoms, and * represents an asymmetric carbon atom.).