JPH0692378B2 - Phenylpiperazine derivative - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application Field >> The present invention relates to a liquid crystal material, and more specifically,
The present invention relates to a novel compound capable of improving the performance of a liquid crystal compound by blending with another liquid crystal compound. Since it does not have liquid crystallinity by itself or takes only a slight intermediate phase, it cannot be expected to be used as a liquid crystal compound, but it has good blendability with other liquid crystal compounds.
Since it has the effect of varying the liquid crystal temperature range of other liquid crystal compounds, it can be considered to be used in this field.

<< Prior Art >> Most liquid crystal compounds used in liquid crystal display devices have a nematic phase. However, in terms of the electro-optical response speed, much more improvement has been attempted compared with the light emitting display device. In recent years, a ferroelectric liquid crystal compound is one of the liquid crystal compounds that has been attracting attention due to its fast response speed. Dodecylbenzylidene-p-amino-2-methylbutyl cinnamate developed in 1975 has attracted attention as a ferroelectric liquid crystal compound. However, this compound has a problem that it takes a chiral smectic phase at high temperature but does not take the same phase at low temperature including room temperature, and it lacks chemical stability because it is a compound containing Schiff base. .

Although many liquid crystal compounds have been synthesized and their properties have been clarified thereafter, no liquid crystal compound having a chiral smectic phase in a wide temperature range including room temperature is known. In order to lower the transition temperature of the liquid crystal phase or widen the temperature range, there is a method of mixing several liquid crystal compounds and the like as a general method adopted in the field of nematic liquid crystals.

Similar methods are being investigated in the field of ferroelectric liquid crystals, and the trial and error is currently under way. It is difficult to predict what kind of skeleton will be selected, what kind of substituent will be introduced, and what kind of liquid crystal phase will be obtained.
It is no exaggeration to say that the phase transition temperature etc. are completely unknown until the compound is tested. For example, a new type of liquid crystal compound having phenylpiperazine in the bone nucleus has been investigated, but it has been clarified that a liquid crystal having a smectic phase can be obtained only by substituting an alkyloxy group on the phenyl nucleus. . (Mol.Cryst.Liq.Cryst., 1981,
Vol.67 49-58) << Problems to be Solved by the Invention >> The present invention is a compound which itself does not take a liquid crystal phase, particularly a chiral smectic C phase, or a slightly different intermediate phase, A novel compound which has a good affinity when mixed with another ferroelectric liquid crystal compound, can change the phase transition temperature of the ferroelectric liquid crystal compound, and increases the bistability as a liquid crystal composition Is.

<< Means for Solving Problems >> The object compound of the present invention is represented by the following general formula.
That is, (In the formula, R ^* is a carbon number of 4 to 9 having an optically active carbon atom.
Is an alkyl group, R is a linear alkyl group having 4 to 10 carbon atoms, and is —CH ₂ — or —CO—. ) Next, the compound represented by the above formula is prepared according to the following chemical reaction formula. That is, 1) a compound in which A is —CH ₂ — in the above general formula: In Reaction 1, R-X means an alkyl halide or an alkyl sulfonate, and the alkyl group is
It is a linear alkyl group such as butyl, pentyl, heptyl, octyl, decanyl, etc., and X represents a halogen atom such as chlorine, bromine, iodine or a sulfonyloxy group such as methanesulfonyloxy and p-toluenesulfonyloxy.
The reaction is carried out at room temperature to heating in the presence or absence of a solvent, and the solvent used is water, methanol, ethanol, benzene, toluene, xylene, tetrahydrofuran, dioxane, dimethylformamide, acetamide, formamide, pyridine. , Triethylamine dimethyl sulfoxide and the like. The compound thus obtained is reacted with the compound represented by R ^* -X in the reaction 2. Here, R ^* is an alkyl group having an optically active carbon atom, such as 2-methylbutyl, 3
-Methylpentyl, 4-methylhexyl, 5-methylheptyl, 6-methyloctyl and the like are shown. X is the same as above. The reaction is carried out in the presence of a basic condensing agent such as sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate, sodium hydride, water, dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, dioxane, pyridine, toluene, xylene, diethylene glycol dimethyl ether. In a solvent such as room temperature to heating.

2) A compound in which A is —CO— in the above general formula: In Reaction 3, R-COZ means an alkylcarbonyl derivative, and Z means -OH or a halogen atom. Examples of the compound in which Z is —OH include linear aliphatic carboxylic acids such as propanoic acid, butanoic acid, pentanoic acid, hexanoic acid and octanoic acid. Examples of the compound in which is a halogen atom include the above linear aliphatic carboxylic acid halides (chloride, bromide, etc.). The reaction is water, triethylamine, tetrahydrofuran, dioxane, dimethylformamide, pyridine,
It is carried out at room temperature to heating in the absence of a solvent such as toluene, xylene, or dimethylsulfoxide.
When Z is -OH, that is, when the reaction is carried out with the carboxyl group as it is, dicyclohexylcarbodiimide, 1,1'-
A condensing agent such as sulfinyldiimidazole may be used.

Compound thus obtained Is subjected to a reaction in Reaction 4 in the same manner as in the method described in 1) Reaction 2 above, (R ^* and R are the same as above).

Examples will be described below to show specific examples of the present invention.

Example 1 1) Synthesis of N-n-butyl-N '-(4-hydroxyphenyl) piperazine: In a 300 ml volumetric flask, 4 g of p-hydroxyphenylpiperazine (0.023 mol, exzahemie), bromide-n.
-Butyl (3.4 g, 0.025 mol) and ethanol (200 ml) were added, and the mixture was refluxed and stirred for 5 hours. After completion of the reaction, the solvent was distilled off, and silica gel column chromatography (5 cmφ × 3
0 cm, developing solvent, chloroform: methanol = 20: 1) gave 1.44 g of the title compound.

IR ν _max (cm ^-1 ): 3200-2400, 1520, 1470, 1380, 124
5,830 2) Synthesis of (S) -Nn-butyl-N '-[4- (2-methylbutyloxy) phenyl] piperazine: In a 50 ml volumetric flask, 0.34 g (0.0) of 50% sodium hydride.
07 mol), 15 ml of dry dimethylformamide and Nn-
Butyl-N '-(4-hydroxyphenyl) piperazine
1.5 g (0.0064 mol) was added, and the mixture was stirred at about 60 ° C for 1 hour.
Thereafter, 1.6 g (0.0066 mol) of (S) -2-methylbutanol p-toluenesulfonic acid ester was dissolved in 5 ml of dimethylformamide and added, and the mixture was stirred at 80 ° C. for 10 hours. After the reaction was completed, it was poured into ice water and extracted with ethyl acetate (5 ml x
3) Washed with 5% KOH aqueous solution (50 ml x 2), washed with saturated saline solution (100 ml x 3), dried over magnesium sulfate, and evaporated to remove the solvent. 1.9 g (97.5%) of brown oily substance Got By purifying by silica gel chromatography (3.5 cm × 30 cm, developing solvent: CHCl ₃ ), the title compound 1.6 was obtained.
I got 1g.

IRν _max (cm ^-1 ): 1520, 1460, 1380, 1240, 820 ¹ H-NMR (CDCl ₃ ) δ (ppm): 0.65 to 2.00 (m, 16H), 2.10
~ 2.80 (m, 6H), 2.85 ~ 3.30 (m, 4H), 3.70 (q, 2H),
6.80 (s, 4H) This compound showed the following transition temperature.

This S _x is a smectic phase close to a crystal.

Example 2 1) Synthesis of N- (4-hydroxyphenyl) -N'-n-octylpiperazine: In a 100 ml volumetric flask, 2 g (0.011 mol) of p-hydroxyphenylpiperazine (manufactured by Ekzahemie) and bromide-
2.4 g (0.012 mol) of n-octyl and 120 ml of ethanol were added, and the mixture was refluxed and stirred for 7 hours. After completion of the reaction, the solvent was distilled off, and the residue was purified by silica gel column chromatography (5 cmφ × 40 cm, developing solvent; CHCl ₃ : MeOH = 20: 1) to obtain 1.03 g of the title compound.

IRν _max (cm ^-1 ): 3200 to 2400, 1520, 1380, 1245, 8302) (S) -Nn- (4-methylhexyloxy) phenyl-N'-n-octylpiperazine: 50 ml female In a flask, 0.19 g (0.0040 mol) of 50% NaH, 10 ml of dry dimethylformamide and 1 g (0.0035) of N- (4-hydroxyphenyl) -N'-n-octylpiperazine.
Mol) and stirred at about 40 ° C. for 30 minutes, then (S) -4-methylhexanol p-toluenesulfonic acid ester 0.94 g
(0.0035 mol) was dissolved in 2 ml of dimethylformamide and added, and the mixture was stirred at 80 ° C. for 10 hours. After the reaction was completed, it was poured into ice water and extracted with ethyl acetate (50 ml × 3), washed with 5% KOH (1
00ml × 2), washed with saturated saline (100ml × 5),
After drying over magnesium sulfate, the solvent was distilled off to give an oily substance 1.25
g (99.9%) was obtained. This was purified by silica gel column chromatography (3 cmφ × 35 cm, developing solvent: CHCl ₃ ) to obtain 1.09 g of the title compound.

IR ν _max (cm ^-1 ): 1520, 1470, 1240, 1155, 820 ¹ H-NMR (60MHz, CDCl ₃ ) δ (ppm): 0.63 (m, 28H), 2.17
~ 2.70 (m, 6H), 3.08 (m, 4H), 3.85 (t, 2H), 6.80
(S, 4H) The compound of this example showed the following transition temperature.

Here, S _x is a smectic phase close to a crystal.

Example 3 1) Synthesis of N-n-caproyl-N '-(4-hydroxyphenyl) piperazine: 10-g of N- (4-hydroxyphenyl) piperazine (manufactured by Exahemie), 7.55 g of n-caproyl chloride and 5.7 of triethylamine. g was added, and the mixture was reacted at room temperature for 24 hours. The reaction solution was poured into ice water, extracted with ethyl acetate, the organic layer was washed with brine and dried over anhydrous magnesium sulfate. After separation by filtration, the solvent was distilled off, and a small amount of ethanol was added to the resulting residue to crystallize it, followed by filtration.
After drying, 6.12 g of the title compound was obtained.

IR v _max (cm ^-1 ): 3330, 1630, 1515, 1255, 1230, 1210 2) (S) -Nn-caproyl-N '-[4'-
Synthesis of (2'-methylbutyloxy) phenyl] piperazine: 0.53 g of 50% sodium hydride was suspended in 3 ml of dry dimethylformamide, and Nn-caproyl-N'- was added thereto.
2.76 g of (4′-hydroxyphenyl) piperazine was dissolved in 5 ml of dry dimethylformamide and added, and the mixture was stirred at 60 ° C. for 90 minutes. Then, (S) -2-methylbutanol p
A mixture of 2.67 g of toluenesulfonic acid ester dissolved in 8 ml of dry dimethylformamide was reacted at 80 ° C. for an hour, poured into ice water, and the product was extracted with ethyl acetate. The organic layer was thoroughly washed with brine, dried over anhydrous magnesium, and separated by filtration. The solvent was distilled off to obtain 3.56 g of an oily substance.
This was purified by silica gel column chromatography to obtain 2.2 g of the title compound.

IR ν _max (cm ^-1 ): 1660, 1520, 1245, 1230 ¹ H-NMR (60MHz, CDCl ₃ ) δ (ppm): 0.65 to 2.0 (m, 18
H), 2.30 (t, 2H), 3.93 (t, 4H), 3.4 to 3.9 (m, 6
H), 6.80 (s, 4H) The compound of this example shows the following transition temperature.

Here, the * mark indicates a supercooled state.

Example 4 The compounds of Examples 1 to 3 were blended with the following pyrimidine-based liquid crystal compositions, and their effects on the transition temperature and the response under AC drive were observed.

In this table, liquid crystal mixing ratios are weight ratios. Regarding the responsiveness under AC drive, the orientation of the substrate on one side is the orientation obtained by rubbing the polyimide film, and the orientation of the other substrate is only treated with the silane coupling agent, and is not subjected to the uniaxial orientation treatment. , Measured with a gap of 2.0 μm,
As the AC waveform, the response speed was defined as the minimum pulse width at which the display was turned on and off when the pulse width was changed by continuously applying the waveform as shown in the figure. (Measured at room temperature.) As shown in the table, by blending the compounds of Examples 1 to 3 with the composition A, the transition temperature from the crystal to the Sc ^* phase can be lowered. Further, the composition A cannot obtain the bistability in the above-mentioned orientation and cannot be driven by an alternating current, but by adding the compound of the present invention, the bistability is generated, the alternating current can be driven, and its responsiveness is also increased. Relatively good.

[Brief description of drawings]

 The figure is a waveform diagram of the voltage applied to the liquid crystal.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masaaki Taguchi 6-31-1, Kameido, Koto-ku, Tokyo Seiko Electronics Co., Ltd. (72) Takamasa Harada 6-31-1, Kameido, Koto-ku, Tokyo Seiko Electronics Industry Co., Ltd.

Claims (1)

[Claims] 1. A formula (In the formula, R ^* is an alkyl group having an asymmetric carbon atom in the molecular chain, R is an alkyl group, and A is -CH ₂ -or -CO-.) A phenylpiperazine derivative.