JP2701064B2 - Alkoxy tolan compounds - Google Patents

Description

The present invention relates to a tolan compound useful as an electro-optical display material. More specifically, the present invention relates to a method for increasing the anisotropy of the refractive index of a liquid crystal material by mixing it with an STN type liquid crystal material. It relates to useful alkoxy tolan compounds.

At present, STN-type liquid crystal cells are being developed toward black-and-white and full-color modes from green or blue mode, and at the same time, studies are underway on high-speed response to moving image support. As a high-speed response, ferroelectric liquid crystals have been studied, but a high-speed response can be expected by making the thickness of the STN-type liquid crystal cell thinner. In that case,
A liquid crystal material with a large refractive index anisotropy (Δn) of the liquid crystal material to be filled in the cell is required. As a typical example, various tolan compounds having a low viscosity and a high Δn have been proposed, but are still insufficient. And a compound exhibiting an even higher Δn have been desired.

In view of the above-mentioned situation, the present inventors have set a low viscosity and a high Δ
As a result of intensive studies to find a compound showing n, it was found that adding a novel alkoxytolan compound represented by the following general formula (I) to the liquid crystal significantly improved the Δn of the liquid crystal.

(Wherein, R represents an alkyl group having 1 to 18 carbon atoms,
R 'represents an alkynyl group or an alkadienyl group having 3 to 17 carbon atoms. In the compound represented by the general formula (I) according to the present invention, 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, dodecyl, tetradecyl, hexadecyl, octadecyl, etc., and the number of carbon atoms represented by R ′ is 3
And alkynyl groups such as 1-propynyl, 1-butynyl, 2-butynyl, 1-pentynyl, 2
-Pentynyl, 1-hexynyl, 4-heptynyl, 6-
Octynyl, 6-noninyl, 7-noninyl, 8-undecinyl, 10-tridecinyl, 12-pentadecynyl and the like are mentioned, and alkadienyl groups are 1,3-butadienyl and 1,6-heptadienyl groups.

The compound represented by the above general formula (I) is a compound represented by R′-
Alcohol represented by CH ₂ —OH and 4-alkoxy-4 ′
-Can be easily produced by reacting with -hydroxytolan.

The alkoxytolan compound of the present invention thus obtained is
When mixed with STN-type liquid crystal materials, it is useful not only for increasing the anisotropy of the refractive index of the liquid crystal material, but also because of its excellent reactivity, it is useful as various synthetic intermediates, especially well-known as a liquid crystal compound. Is useful as an intermediate for obtaining the alkoxytolan compound.

 Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1 Synthesis of 4-n-heptyloxy-4 '-(2,7-octadienyloxy) tolan 0.07 g (0.55 mmol) of 2,7-octadien-1-ol,
4-n-heptyloxy-4'-hydroxytolan 0.15
g (0.5 mmol) and 0.16 g of triphenylphosphine were dissolved in 1.5 of dry diethyl ether, and then a solution of 0.12 g of azodicarboxylic acid diisopropyl ester in 0.5 of dry diethyl ether was added dropwise over about 3 minutes. After stirring at room temperature for 3.5 hours, the precipitated triphenylphosphine oxide was filtered off, and the filtrate was desolvated. The residue was purified by a silica gel column using n-hexane / diethyl ether (95/5) as a developing solvent to obtain 0.19 g of the desired 4-n-heptyloxy-4 '-(2,7-octadienyloxy) tolan. Obtained.

Melting point: 105.2 to 106.1 ° C. As a result of infrared spectroscopy, the obtained product had the following characteristic absorption and was confirmed to be the desired product.

2925cm ^-1 , 2855cm ^-1 , 2550cm ^-1 , 1610cm ^-1 , 1515cm ^-1 ,
1285 cm ^-1 , 1245 cm ^-1 , 1005 cm ^-1 , 835 cm ^-1 , 535 cm ^-1 Example 2 Synthesis of 4-n-heptyloxy-4 '-(2-butynyloxy) tolan 2-butyn-1-ol 0.05 g (0.66 mmol), 4-n
Heptyloxy-4'-hydroxytolan 0.18 g (0.6
mmol) and triphenylphosphine 0.19 g were dissolved in dry diethyl ether 2.0, and azodicarboxylic acid diisopropyl ester 0.15 g was added dropwise with dry diethyl ether 0.5 over 3 minutes. After stirring at room temperature for 3.5 hours, the precipitated triphenylphosphine oxide was filtered off, and the filtrate was desolvated. The residue was purified with n-hexane / ethyl acetate (95 /
Using 5) as a developing solvent, silica gel column purification was performed to obtain 0.15 g of the desired 4-n-heptyloxy-4 '-(2-butynyloxy) tolan.

Melting point: 115.0 ° C. As a result of infrared spectroscopy, the obtained product had the following characteristic absorption and was confirmed to be the desired product.

^{2975cm -1, 2850cm -1, 2250cm -1} , 1605cm -1, 1515cm -1,
^{1280cm -1, 1240cm -1, 1000cm -1} , 835cm -1, 535cm -1 Example 3 4-n-heptyloxy-4 '- (2-pentynyloxy) Tran Synthesis of 0.05 g (0.66 mmol) of 2-pentyn-1-ol, 4-
0.18 g of n-heptyloxy-4'-hydroxytolan
(0.6 mmol) and 0.19 g of triphenylphosphine were dissolved in 2.0 of dry diethyl ether, and then 0.15 g of diisopropyl azodicarboxylate was added to dry diethyl ether.
It was added dropwise over 3 minutes with 0.5. After stirring at room temperature for 4 hours,
The precipitated triphenylphosphine oxide was filtered off, and the filtrate was desolvated. The residue was purified by a silica gel column using n-hexane / ethyl ether (97/3) as a developing solvent.
0.08 g of desired 4-n-heptyloxy-4 '-(2-pentynyloxy) tolane was obtained.

Melting point: 98.7 ° C. As a result of infrared spectroscopy, the obtained product had the following characteristic absorption and was confirmed to be the desired product.

^{2950cm -1, 2875cm -1, 2250cm -1} , 1610cm -1, 1520cm -1,
^{1380cm -1, 1245cm -1, 1010cm -1} , 840cm -1, 540cm -1 Example 4 4-n-heptyloxy-4 '- (3-hexynyloxy) Tran Synthesis of 0.05 g (0.55 mmol) of 3-hexyn-1-ol, 4-
0.15 g of n-heptyloxy-4'-hydroxytolan
(0.5 mmol) and 0.16 g of triphenylphosphine were dissolved in dry diethyl ether, and then 0.12 g of diisopropyl azodicarboxylate was added dropwise together with 0.5 of dry diethyl ether over 3 minutes. After stirring at room temperature for 4 hours, the precipitated triphenylphosphine oxide was filtered, and the filtrate was desolvated. The residue was purified with n-hexane / ethyl ether (96
Using / 4) as a developing solvent, silica gel column purification was performed to obtain 0.07 g of the desired 4-n-heptyloxy-4 '-(3-hexynyloxy) tolan.

Melting point: 68.8 ° C. As a result of infrared spectroscopy, the obtained product had the following characteristic absorption and was confirmed to be the desired product.

2950cm ^-1 , 2875cm ^-1 , 2300cm ^-1 , 1615cm ^-1 , 1520cm ^-1 ,
1520cm ^-1 , 1290cm ^-1 , 1255cm ^-1 , 1050cm ^-1 , 845cm ^-1 , 8
By adding 30 cm ^-1, a novel alkoxy tolans becomes 540 cm ^-1 Reference Example present invention to a liquid crystal, to see to improve the liquid crystal of [Delta] n, becomes following composition 1: 1: 1 mixture of Mix with 10% tolane compound Each change in Δn was measured, and the results are shown below.

As is clear from the above results, the novel alkoxytolan compound according to the present invention has an effect of increasing the value of Δn of the mother liquid crystal.

Claims (1)

(57) [Claims] 1. An alkoxytolan compound represented by the following general formula (I). (Wherein, R represents an alkyl group having 1 to 18 carbon atoms,
R 'represents an alkynyl group or an alkadienyl group having 3 to 17 carbon atoms. )