JPH0796530B2 - 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 (Applied Physics Letter (Appl.Phys.Lett., 36 , 899). (198
0))).

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 cause isomerization by light within a short period of time, or hydrolyze due to water to show no liquid crystal phase. It is not preferable as a display element because it has an unstable element.

The object of the present invention is to eliminate such an unstable element. Another object of the present invention is to provide a novel compound having photochemical and chemical stability and useful as an intermediate of a ferroelectric liquid crystal having a ferroelectric phase.

[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, R represents an alkyl group having 1 to 20 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, R and * are the same as above, and Bz represents a benzyl group.) That is, after 2,6-hydroxynaphthalenecarboxylic acid (a) is benzylated to form compound (b), thionyl chloride and shu The acid chloride derivative (c) is prepared using an acid chloride or the like.

Then, (c) is reacted with various optically active 2-alkoxypropanols to obtain an ester body (d). Thereafter, debenzylation can be carried out 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 a known substance as described in, for example, Journal of Chemical Society (J. Chem. Soc., 1954 , 678). is there.

As the optically active 2-alkoxypropanol, specifically, optically active 2-methoxypropanol, optically active 2-ethoxypropanol, optically active 2-propoxypropanol, optically active 2-butoxypropanol, optically active 2-pentyloxypropanol, Optically active 2-hexyloxypropanol, optically active 2-heptyloxypropanol, optically active 2-octyloxypropanol, optically active 2-nonyloxypropanol, optically active 2-decyloxypropanol, optically active 2-dodecyloxypropanol, optically active 2-tetradecyloxypropanol, optically active 2-hexadecyloxypropanol, optically active 2-octadecyloxypropanol, optically active 2- (2'-methylpropoxy) propanol, optically active 2 (3'-methylbutoxy) can be mentioned propanol.

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-
Alkylnaphthalene-2-carboxylic acid, 6-alkoxynaphthalene-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′-
Il) benzoic acid, 4- (trans-5'-alkyl-)
1 ', 3'-dithiaoxan-2'-yl) benzoic acid, 4
-(Trans-5'-alkyl-1 ', 3'-dithiane-
2'-yl) benzoic acid, 4- (5'-alkyl-1 ',
3 ', 2'-dioxaborinan-2'-yl) benzoic acid or a benzene ring or naphthalene of these compounds is reacted with a derivative in which a halogen atom, a cyano group, a nitro group, a methyl group or an ethyl group is substituted on the ring. It is possible to obtain a very useful ferroelectric liquid crystal.

For example, a compound represented by the general formula (II) produced from the compound (I) of the present invention and 4-alkoxybenzoic acid or 4- (4'-alkoxyphenyl) benzoic acid. (In the formula, R ₁ is an alkyl group having 1 to 20 carbon atoms, m is an integer of 1 or 2, R ₂ is an alkyl group having 1 to 20 carbon atoms, and * indicates an asymmetric carbon atom. ) Indicates a chiral smectic C phase as shown in the specific examples in Table 2, and is a non-constituent component when preparing a ferroelectric liquid crystal mixture that operates near room temperature. Always important.

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 6-hydroxynaphthalene-2-carboxylic acid- (2'-
Propoxy) propyl ester (in formula (I) R =
Production of C ₃ preparation of compound H of ₇₎ (i) 6- Benzyloxy-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-
Preparation of carboxylic acid- (2'-propoxy) propyl ester The acid chloride obtained in (ii) was dissolved in 100 ml of toluene,
A solution of 27 g of (s) -2-propoxypropanol dissolved in 30 ml of pyridine was added to this solution, and the mixture was allowed to stand at room temperature for 8 hours. After separating the precipitated pyridine hydrochloride by filtration, the organic layer was separated.
It was washed with 2N-hydrochloric acid, further washed with 2N-sodium hydroxide aqueous solution, and further washed with water until it became neutral.

Separate the organic layer and distill off the toluene under reduced pressure to remove the desired product (65 g).
Obtained.

'H-NMR (in CDCl ₃ ) δ (ppm) 0.9-1.8 (8H), 3.4-4.4 (5H) 5.2 (2H), 7.2-8.5 (11H) (iv) (iii) (s)- 60 g of 6-benzyloxynaphthalene-2-carboxylic acid- (2'-propoxy) propyl ester was dissolved in 200 ml of ethanol and hydrogenated at 40 ° C under normal pressure in the presence of 5% palladium / carbon 4g. After the palladium / carbon was filtered off, the solvent was distilled off under reduced pressure to obtain 44 g of the target (s) -6-hydroxynaphthalene-2-carboxylic acid- (2'-propoxy) propyl ester.

′ H-NMR (in CDCl ₃ ) δ (ppm) 0.9 to 1.8 (8H), 3.4 to 4.4 (5H) 7.2 to 8.5 (7H) The elemental analysis values of this compound are theoretical values as shown in Table 3. Well matched.

Examples 2 to 9 The method described in (iii) of Example 1 except that various optically active 2-alkoxypropanols were used in place of (s) -2-propoxypropanol in (iii) of Example 1. In accordance with various optically active 6-benzyloxynaphthalene-2-carboxylic acids The acid- (2'-alkoxy) propyl ester was prepared.

Further, in (iv) of Example 1, instead of (S) -6-benzyloxynaphthalene-2-carboxylic acid- (2'-propoxy) propyl ester, various optically active 6-benzyloxynaphthalene-2-carboxylic acid- Example 1 except that (2'-alkoxy) propyl ester was used.
Various optically active 6-hydroxynaphthalene-2-carboxylic acid- (2'-alkoxy) propyl esters were produced according to the method described in (iv) of the above.

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, R represents an alkyl group having 1 to 20 carbon atoms, and * indicates an asymmetric carbon atom).