JP2503440B2 - Fluorine-containing propane nitrile compound - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel fluorine-containing compound. Specifically, it relates to a novel fluorine-containing propanenitrile compound that can be used as a component of a liquid crystal composition.

BACKGROUND OF THE INVENTION Since liquid crystal compounds have been used in electro-optical display devices, numerous liquid crystal substances have been synthesized, nematic liquid crystal or nematic-cholesteric liquid crystal twisted nematic mode display devices, cholesteric-nematic phase transition phenomenon display devices, Further, it is widely used as a display device utilizing guest-host effect, and liquid crystal display using a chiral smectic C liquid crystal is also under study.

These liquid crystal compounds are required to be stable to moisture, air, light, heat, etc., and need not only be in a liquid crystal state at room temperature, but also in a liquid crystal state in a wide temperature range from low temperature to high temperature. Which exhibits a high response speed.

[Structure of the Invention] The object of the present invention is to provide a novel compound which provides a liquid crystal composition satisfying the above requirements.

That is, the present invention provides a compound represented by the general formula [I]: (In the formula, R represents an alkyl group.) A fluorine-containing propanenitrile compound represented by:

The fluorinated propanenitrile compound of the present invention can be used in combination with a suitable known liquid crystal compound,
It can be used as a liquid crystal composition having low viscosity and high-speed response.

 Hereinafter, the present invention will be described in detail.

The fluorine-containing propanenitrile compound of the present invention is represented by the above general formula [I], and the substituent R thereof is an alkyl group, preferably R is an alkyl group having 1 to 8 carbon atoms. .

Such a fluorinated propanenitrile compound of the present invention can be obtained, for example, by the following synthetic methods by the following reactions.

(Note that R in the general formulas [II] and [IV] to [VIII] has the same meaning as in the above general formula [I].) The above reaction is carried out by, for example, dimethylformamide, N.
It can be carried out in an organic solvent such as monomethylpyrrolidone in the presence of copper powder at a temperature of, for example, 100 to 200 ° C.

The reaction can be carried out, for example, in an alcoholic solvent such as ethanol in the presence of zinc at a temperature of, for example, 70 ° C to 100 ° C.

The reaction of, for example, in a ketone solvent such as acetone,
For example, it can be performed by oxidizing with potassium permanganate at −10 ° C. to 50 ° C.

The reaction of, for example, benzene, an aromatic solvent such as toluene, carbon tetrachloride, a chlorine solvent such as chloroform, dioxane, in the presence of an organic solvent such as an ether solvent such as tetrahydrofuran, or in the absence of these solvents, It can be carried out at a reaction temperature of, for example, 50 to 100 ° C. with a chlorinating agent such as thionyl chloride.

The reaction can be carried out with ammonia or the like in the presence or absence of an organic solvent such as an ether solvent such as diethyl ether, dioxane or tetrahydrofuran at a reaction temperature of, for example, -10 ° C to 100 ° C.

The reaction of, for example, with a dehydrating agent such as phosphorus pentoxide,
For example, it can be performed at a reaction temperature of 100 to 250 ° C.

When a liquid crystal composition is formed using the fluorine-containing propanenitrile compound of the present invention, it can be used in combination with a suitable known liquid crystal compound. Examples of such known liquid crystal compound include ester-based and diester-based compounds. Examples include azoxy series, azo series, Schiff series, pyrimidine series, biphenyl series, phenylcyclohexane series, cyclohexylcyclohexane series, bicyclooctane series, dioxane series, and polycyclic compound series composed of benzene ring and cyclohexane ring. Further, when a liquid crystal composition is formed using the compound of the present invention, known additives such as a dichroic dye or a viscosity reducing agent may be used in combination.

EXAMPLES Next, the present invention will be specifically described by way of examples, but the present invention is not limited to the following examples unless it exceeds the gist.

Example 1 3- (P- (4-trans-n-propylcyclohexyl) -phenyl) -tetrafluoropropanenitrile Prior to the reaction, 100 g of copper sulfate was dissolved in 350 ml of warm water, the temperature was raised to room temperature, and 35 g of zinc was slowly added. This causes copper to precipitate. This was washed by decanting 5 times with 200 ml of water each time, and 100 ml of 5% dilute hydrochloric acid was used to dissolve and remove the remaining zinc to obtain precipitated copper.

2.539 g (7.74x10 ^-3 mo) of 4- (4-trans-n-propylcyclohexyl) -iodobenzene [IIa] on the ampoule
l), 3,4-dichloro-1-iodoperfluorobutane [II
I] 8.1538 g (2.15 × 10 ^-2 mol), the above precipitated copper 4.9586 g (7.
(8x10 ^-2 mol) and anhydrous dimethylformamide (8 ml) were sealed, and the mixture was heated and stirred at 135 ° C for 24 hours. After completion of the reaction, 100 ml of water was added to the reaction solution, suction filtration was performed, the filtration was extracted with diethyl ether (150 ml x 5 times), and washed with saturated saline solution (50 ml x 2).
Times), dried over anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain an oily substance. The impurities were separated by column chromatography (silica gel; hexane), and 1- (3,4-dichloroperfluorobutyl) -4- (4-trans-n-propylcyclohexyl) -benzene [IVa] and 1- (3-perfluoro 2.2245 g of a mixture with butenyl) -4- (4-trans-n-propylcyclohexyl) -benzene [Va] was obtained.

This structure was confirmed by the results of NMR and HIGH MASS below.

2.225 g of a mixture of [IVa] and [Va] obtained in reaction (i)
Zinc 0.995g (1.52 × 10 ^-2 mol) and 99% ethanol 20ml
Was added, the mixture was heated under reflux for 1 hour, excess zinc was removed by column chromatography (silica gel; dichloromethane), and the mixture was concentrated under reduced pressure to obtain [Va] (2.373 g).

To 2.373 g of [Va] obtained in the reaction (ii), 5.437 g (3.46x10 ^-2 mol) of potassium permanganate and 20 ml of acetone were added, and ice-
It was cooled to 0 ° C. in a salt bath and stirred at the same temperature for 16 hours. After the completion of the reaction, in order to remove excess potassium permanganate, 42 ml of methanol, 10 ml of 10% hydrochloric acid, 100 ml of diethyl ether, sodium chloride and sodium bisulfite were added to the reaction solution. Crystals were slightly precipitated, so it was filtered off and extracted with diethyl ether (200mlx5
Times), dried over anhydrous sodium sulfate, and concentrated under reduced pressure to obtain a crystal product. This is separated and purified by column chromatography (silylated silica gel; hexane: benzene = 2: 1),
Recrystallized from benzene-hexane to give white needle crystals 3- (p- (4-trans-n-propylcyclohexyl)-
Phenyl) -tetrafluoropropionic acid [VIa] 0.712
g (2.05 × 10 ⁻³ mol) was obtained.

[VIa] had liquid crystallinity and the phase transition points were as follows.

The results of NMR, IR and elemental analysis were as shown below.

IR (KBr) cm ^-1 : 3400 (m.broad), 2945 (S), 2850 (m) 1760 (S), 1615 (m), 1440 (m) 1300 (m), 1140 (S), 920 ( m) 830 (m) Elemental analysis value (%) C: 62.42H: 6.40 C ₁₈ H ₂₂ F ₄ O ₂ calculated value (%) 0.526 g of [VIa] obtained in (iii) above in 5 ml of anhydrous benzene
(1.52x10 ^-3 mol) and anhydrous dimethylformamide 3 drops further dissolved thionyl chloride ^{3.5ml (4.82 × 10 -2 mol)} , was heated under reflux for 24 hours. After that, benzene at the same temperature,
Excess thionyl chloride was distilled off under reduced pressure. This was returned to room temperature, further cooled, 15 ml of anhydrous diethyl ether was added, and the mixture was cooled with ice, and then ammonia gas was blown therein for 20 minutes. To this reaction solution, 50 ml of saturated saline and 30 ml of diethyl ether were added, extracted with diethyl ether (30 ml x 5 times), dried over anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain a crystal product. The obtained crystals were recrystallized from benzene-hexane to give 3-
(P- (4-n-Propylcyclohexyl) -phenyl) -tetrafluoropropionic acid amide [VIIIa] 0.389 g (1.1
2 × 10 −3 mol) was obtained (74% yield).

This compound has a transition temperature from crystal to nematic liquid crystal
At 178 ℃, the transition temperature from nematic liquid crystal to isotropic liquid was 190 ℃.

1.600 g (1.39x10 ^-2 mol) of diphosphorus pentoxide was placed in the flask, and 3- (p- (4-n-propylcyclohexyl) -phenyl) -tetrafluoropropionic acid amide [(iv) obtained above in (iv)] VIIIa] 0.278 g (8.0 × 10 ⁻⁴ mol) was added. Nitrogen was blown into this to make the reaction system anhydrous, and then heated in a silicone oil bath at 200 ° C. for 1 hour under reduced pressure.
After the reaction is complete, add 30 ml of diethyl ether and 50
ml was poured slowly. Extract with diethyl ether (30
(mlx3 times), dried over anhydrous magnesium sulfate, and concentrated under reduced pressure to give an oil. This oil was separated and purified by column chromatography (silica gel; hexane) to give a colorless and transparent oil 3- (p- (4-n-propylcyclohexyl) -phenyl) -tetrafluoropropanenitrile [Ia] 0.179 g
(5.47x10 ^-4 mol) was obtained (yield 68%).

The physical properties of the obtained compound [Ia] were as follows.

IR (lf) cm ^-1 : 2950 (S), 2860 (m), 2270 (m) 1620 (m), 1450 (m), 1160 (S) 830 (m) Elemental analysis value (%) C: 66.16 H : 6.49 N: 4.19 Calculated value as C ₁₈ H ₂₁ F ₄ N (%) C: 66.04 H: 6.47 N: 4.28 Example 2 The fluorine-containing compound obtained in Example 1 was obtained from E. Merck.
LI-1132 (Transition temperature from crystal to nematic liquid crystal; -6
℃, transition temperature from nematic liquid crystal to isotropic liquid crystal; 70
C.) was mixed with a commercially available mixed liquid crystal at 10% by weight, the transition temperature from the nematic liquid crystal to the isotropic liquid was
It was 60.8 ° C. The temperature at which the crystal phase transitions to the nematic phase was difficult to measure because the sample was difficult to crystallize due to the supercooling phenomenon.

[Effects of the Invention] As described in detail above, the fluorine-containing propanenitrile compound of the present invention is a novel compound that can be used as a component of a liquid crystal composition, and should be used in combination with a known liquid crystal compound. It is stable against moisture, air, light and heat.

 It shows a liquid crystal state in a wide temperature range.

 Low viscosity and high response speed.

And the like, and is industrially extremely useful.

Claims (2)

(57) [Claims] 1. A general formula [I] (In the formula, R represents an alkyl group.) A fluorine-containing propanenitrile compound represented by the formula: 2. In the general formula [1], R has 1 to 8 carbon atoms.
The fluorine-containing propanenitrile compound according to claim 1, which is an alkyl group of