JPH0739398B2 - Liquid crystalline pyrazine derivative - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel liquid crystalline pyrazine derivative. More specifically, the present invention relates to a pyrazine derivative bonded with a substituent having optically active carbon, which exhibits excellent properties as a liquid crystal.

BACKGROUND OF THE INVENTION Liquid crystal display has been widely used as a display method in recent years, but a TN type display method is generally used as a liquid crystal display method at present. A nematic liquid crystal compound is generally used for this TN type display system.

However, the TN type display method using a nematic liquid crystal compound has a basic problem that the response speed is slow and that high multiplex driving is unreasonable. Researches on display methods using smectic liquid crystal compounds with few problems have been actively conducted.

In particular, the chiral smectic C phase (hereinafter sometimes simply referred to as “SmC * phase”), which is exhibited by a smectic liquid crystalline compound having optically active carbon (asymmetric carbon) in the molecule, exhibits ferroelectricity, and It is known to have responsiveness. Further, for example, it has been reported that when such a compound is injected into a thin cell having a thickness of about 1 μm, it has a memory property, and the development of a new display device utilizing this property is underway [N TA Clark (NAClark), et al: (. Applied Phys.lett) Applied Physics letters, 36, 899 (1980)].

The first reported liquid crystal compound exhibiting the SmC * phase was D developed by Meyer et al. In 1975.
OBAMBC [(S) -2-methylbutyl = p- (pn-decyloxybenzylideneamino) cinnamate], but due to subsequent development, in addition to liquid crystal compounds having a structure similar to DOBAMBC, Schiff New types of liquid crystalline compounds such as base-based, ester-based and biphenyl-based have been developed.

For example, JP-A-60-92276 discloses an invention of a pyrazine derivative in which a substituent having optically active carbon is introduced into pyrazine, and this derivative is a chiral smectic C.
It has been shown to exhibit phases. The pyrazine derivative disclosed in the present invention has the above-mentioned excellent properties as a liquid crystal compound, but has sufficient stability under severe conditions such as when stored for a long time at high temperature due to the structure of the compound. There is a problem that is not.

[Object of the Invention] An object of the present invention is to provide a novel liquid crystalline pyrazine derivative.

SUMMARY OF THE INVENTION The pyrazine derivative newly provided by the present invention is represented by the following general formula (I).

However, in the general formula (I), R ¹ is an alkyl group having 1 to 18 carbon atoms, an alkoxy group, an acyloxy group, a p-alkylbenzoyloxy group, or a p-alkoxybenzoyloxy group, and R ² is a carbon number. An alkyl group or an alkoxy group having 1 to 18, wherein at least one of R ¹ and R ² is a group exhibiting optical activity.

DETAILED DESCRIPTION OF THE INVENTION The pyrazine derivative of the optically active liquid crystal provided by the present invention is represented by the general formula (I).

R ¹ represents an alkyl group having 1 to 18 carbon atoms, an alkoxy group, an acyloxy group, a p-alkylbenzoyloxy group, or a p-alkoxybenzoyloxy group, and examples thereof include methyl, ethyl, n-propyl and n. -Butyl,
2-methylbutyl, n-pentyl, 3-methylpentyl, n-hexyl, 4-methylhexyl, n-heptyl, 5-methylheptyl, n-octyl, 2-octyl, 6-methyloctyl, n-nonyl, 7- Methylnonyl, n-decyl, 8-methyldecyl, n-undecyl,
n-dodecyl, n-tridecyl, n-tetradecyl, n
-Alkyl groups such as pentadecyl, n-hexadecyl, n-heptadecyl and n-octadecyl; methoxy, ethoxy, propoxy, n-butoxy, 2-methylbutoxy, n-pentyloxy, 3-methylpentyloxy, n-hexyloxy. , 4-methylhexyloxy, n-heptyloxy, 5-methylheptyloxy,
n-octyloxy, 2-octyloxy, 6-methyloctyloxy, n-nonyloxy, 7-methylnonyloxy, n-decyloxy, 8-methyldecyloxy,
Alkoxy groups such as n-undecyloxy, n-dodecyloxy, n-tridecyloxy, n-tetradecyloxy, n-pentadecyloxy, n-hexadecyloxy, n-heptadecyloxy or n-octadecyloxy Ethanoyloxy, propanoyloxy, butanoyloxy, pentanoyloxy, hexanoyloxy, heptanoyloxy, octanoyloxy, nonanoyloxy, decanoyloxy, undecanoyloxy, dodecanoyloxy, tridecanoyloxy, tetra Acyloxy groups such as deicanoyloxy, pentadecanoyloxy, hexadecanoyloxy, heptadecanoyloxy, octadecanoyloxy; p-methylbenzoyloxy, p-ethylbenzoyloxy, p-propylbenzoyloxy Shi, p- butyl benzoyloxy, p- (2-methylbutyl) benzoyloxy, p-
A p-alkylbenzoyloxy group such as pentylbenzoyloxy, p-hexylbenzoyloxy, p-heptylbenzoyloxy, p-octylbenzoyloxy, p-nonylbenzoyloxy, p-decylbenzoyloxy, p-undecylbenzoyloxy; And p
-Methoxybenzoyloxy, p-ethoxybenzoyloxy, p-propoxybenzoyloxy, p-butoxybenzoyloxy, p- (2-methylbutoxy) benzoyloxy, p-pentyloxybenzoyloxy,
p- (3-methylpentyloxy) benzoyloxy,
p-hexyloxybenzoyloxy, p-heptyloxybenzoyloxy, p- (4-methylhexyloxy) benzoyloxy, p-octyloxybenzoyloxy, p- (2-octyloxy) benzoyloxy, p-nonyloxybenzoyloxy And p-alkoxybenzoyloxy groups such as p-decyloxybenzoyloxy and p-undecyloxybenzoyloxy. However, one of the methylene groups in the alkyl chain of each group may be replaced by an oxygen atom.

R ² represents an alkyl group or an alkoxy group having 1 to 18 carbon atoms, examples of which include methyl, ethyl, n-propyl,
n-butyl, 2-methylbutyl, n-pentyl, 3-methylpentyl, n-hexyl, 4-methylhexyl, n
-Heptyl, n-octyl, 2-octyl, 6-methyloctyl, n-nonyl, n-decyl, 8-methyldecyl, n-undecyl, n-dodecyl, n-tridecyl,
alkyl groups such as n-detradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl and n-octadecyl; and methoxy, ethoxy, propoxy,
n-butoxy, 2-methylbutoxy, n-pentyloxy, 3-methylpentyloxy, n-hexyloxy,
4-methylhexyloxy, n-heptyloxy, n-
Octyloxy, 2-octyloxy, 6-methyloctyloxy, n-nonyloxy, n-decyloxy, 8
-Methyldecyloxy, n-undecyloxy, n-dodecyloxy, n-tridecyloxy, n-tetradecyloxy, n-pentadecyloxy, n-hexadecyloxy, n-heptadecyloxy or n-octadecyloxy And an alkoxy group such as
However, one of the methylene groups in the alkyl chain of each group may be replaced by an oxygen atom.

Further, at least one of R ¹ and R ² needs to be an optically active group having an asymmetric carbon. This optically active group is (S)
-2-methyl-butoxy group, (S) -4-methylhexyloxy group, (R) -2-octyloxy group, (S)-
2-octyloxy group, (S) -8-methyldecyloxy group, (S) -2-methylbutyl group, (S) -4-methylhexyl group, (R) -2-octyl group, (S) -2 −
It is preferably a group selected from the group consisting of an octyl group and a (S) -8-methyldecyl group.

The pyrazine derivative of the present invention can be produced, for example, by the method described below.

B) In the general formula (I), R ¹ is an alkyl group or an alkoxy group and R ² is an alkyl group or an alkoxy group. That is, 5- (4-substituted phenyl) pyrazinol
Chlorination in dimethylaniline using POCl ₃ etc.,
Then, a Grineer reagent (when R ² = alkyl group) or a sodium alkoxide (when R ² = alkoxy group) is allowed to act on this, to obtain the desired pyrazine derivative (I).

B) In the general formula (I), R ¹ is an alkoxy group, an acyloxy group, a p-alkylbenzoyloxy group or a p-alkoxybenzoyloxy group, and R ² is an alkyl group. That is, 5- (p-methoxyphenyl) -2-alkylpyrazine obtained by hydrolysis with hydrobromic acid
It can be obtained by etherifying (p-hydroxyphenyl) -2-alkylpyrazine with alkyl bromide or esterification with carboxylic acid chloride or carboxylic acid anhydride.

C) In the general formula (I), R ¹ is an alkoxy group, an acyloxy group, a p-alkylbenzoyloxy group or a p-alkoxybenzoyloxy group, and R ² is an alkoxy group. That is, 2-chloro-5- (p-methoxyphenyl)
2-Bromo-5- (p-hydroxyphenyl) pyrazine obtained by hydrolyzing pyrazine with hydrobromic acid is reacted with excess sodium alkoxide to give 2-alkoxy-5- (p-hydroxyphenyl) pyrazine. obtain. This can be etherified with alkyl bromide or esterified with carboxylic acid chloride or the like to obtain the desired pyrazine derivative (I).

The pyrazine derivative of the present invention is very stable thermally, and is characterized in that it exhibits high stability even during long-term storage under high temperature conditions in contact with water. Moreover, the pyrazine derivative of the present invention has excellent compatibility with other compounds (liquid crystal compounds having SmC * phase, SmF * phase or cholesteric phase, or compounds introduced into known liquid crystal compositions). There are also advantages.

Further, since the pyrazine derivative of the present invention is a chiral compound, even when it is used as an additive for a liquid crystal composition, the spontaneous polarization of other liquid crystal compounds is less likely to decrease.

Therefore, by using the pyrazine derivative of the present invention as a component of a liquid crystal composition, an element having a good memory property can be produced, and an element having a high-speed response can be produced. is there.

Next, a synthesis example of the pyridine derivative of the present invention will be shown.

[Example 1] Production of 2-((S) -2-methylbutoxy) -5- (p-octyloxyphenyl) pyrazine 2-chloro-5- (p-octyloxyphenyl) pyrazine (JP-A-61-1 129171 gazette) 3.19 g of tetrahydrofuran (THF) 20 ml solution was added to sodium (S) -2-
It was added to a THF solution of methyl butoxide (adjusted from 2.64 g of (S) -2-methylbutanol, 0.96 g of NaH and 40 ml of THF) and stirred at 50 ° C. for 1 hour. Water 20 in this reaction
After adding dropwise ml, the mixture was extracted with benzene (50 ml × 2). After drying, the solvent was distilled off and the obtained crystal was subjected to silica gel column chromatography (developing solution: benzene), and recrystallization was repeated from ethanol to give 2-((S) -2-
1.69 g of white crystals of methylbutoxy) -5- (p-octyloxyphenyl) pyrazine were obtained. This compound (C ₂₃
The elemental analysis values for H ₃₄ N ₂ O ₂ ) were in good agreement with the calculated values as shown below.

NHN Measured value: 74.38% 9.31% 7.70% Calculated value: 74.56% 9.25% 7.55% IR (KBr) cm ^-1 : 2950, 2920, 2850, 1605, 1455, 1335,
1290, 1260, 1170, 1050, 1015, 830, 815 [Example 2] 2-((S) -4-methylhexyloxy) -5- (p
Preparation of -octyloxyphenyl) pyrazine Preparation was carried out in the same manner except that (S) -4-methylhexanol was used instead of (S) -2-methylbutanol used in Example 1.

IR (KBr) cm ^-1 : 2950, 2930, 2860, 1610, 1465, 1320,
1295, 1250, 1180, 1020, 835, 820 [Example 3] 2-((S) -8-methyldecyloxy) -5- (p-
Production of Octyloxyphenyl) pyrazine The title compound was produced in the same manner except that the following (S) -8-methyldecanol was used instead of the (S) -2-methylbutanol used in Example 1.

Elemental analysis CHN Actual value: 76.48% 10.26% 6.16% Calculated value: 76.60 10.20 6.11 (as C ₂₉ H ₄₆ N ₂ O ₂ ) IR (KBr) cm ^-1 : 2920, 2850, 1610, 1510, 1460, 1360 ,
1350, 1300, 1245, 840 NMR (CDCl ₃ ) ppm: 0.85 (9H, J = 6.3Hz) 1.0 to 1.9 (27H, m) 4.00 (2H, J = 6.3Hz) 4.33 (2H, J = 6.8Hz) 6.98 (2H, J = 8.8Hz) 7.83 (2H, J = 8.8Hz) 8.23 (1H, J = 1.0Hz) 8.42 (1H, J = 1.0Hz) (S) -8-Methyldecanol production 250ml methanol 454 g of 1.6-dibromohexane (1.82
Sodium methoxide (Na4
2.8g, prepared from 1.825mol) 500ml of methanol
The solution was added and heated to reflux for 4 hours. The precipitate was filtered, the filtrate was concentrated and 400 ml of water was added to it and ether (300 ml x 1, 100 m
It was extracted with l × 1). After the solvent was distilled off, it was fractionally distilled to obtain 144.6 g of a fraction (98 to 111 ° C / 29 mmHg, gas chromatography (GC)
From the analysis, a mixture of 1,6-dimethoxyhexane 14.9%, 1-bromo-6-methoxyhexane 81.8% and 1.6-dibromohexane 3.3% was obtained).

A solution of Grineer reagent prepared by dropping 144.6% of the above-mentioned distillate into 260 ml of THF containing 22.2 g of Mg and heating the mixture (S)-
2-Methylbutyltoluene sulfonate 125.2g THF200
Li ₂ CuCl ₄ (LiCl 0.10 g and CuCl ₂ 0.16
20 ml of THF solution obtained by mixing g) was added, and the mixture was heated under reflux for 7 hours. After cooling, saturated aqueous NH ₄ Cl 800ml and 2N hydrochloric acid 30
After adding 0 ml, the mixture was extracted with ether (200 ml × 5). After drying and concentration, fractional distillation is performed to obtain a fraction (G
By C analysis, 81.9 g of (S) -8-methyl-1-methoxydecane content was confirmed to be 95.5%).

50 ml of 47% hydrobromic acid (d = 1.48) and 350 ml of acetic acid were added to 81.9 g of the above-mentioned fraction, and the mixture was heated under reflux for 7.5 hours. The mixture was concentrated under reduced pressure, neutralized with sodium carbonate, and extracted with ether. After drying and concentrating, fractionation was performed to obtain a fraction having a boiling point of 122 to 128 ° C / 9 mmHg (according to GC analysis, (S) -8-methyldecyl bromide 13.6% and (S) -8-methyldecyl acetate 86.4%. 47.9 g was obtained).

47.9 g of the above-mentioned fraction was added to a solution of 300 ml of methanol in which 220 g of caustic soda was dissolved, and the mixture was stirred at room temperature for 2 hours, concentrated, water was added, and the mixture was extracted with ether. The liquid obtained by drying and concentrating was subjected to silica gel column chromatography (developing solution; ether hexane) to obtain 31.5 g of (S) -8-methyldecanol.

IR (liquid film) cm ^-1 : 3400, 2940, 2900, 2840, 1450, 137
0,1050 NMR (CDCl ₃ ) ppm: 0.851 (6H, J = 5.9Hz) 1.04 to 1.16 (2H, m) 1.287 (10H, bs) 1.558 (2H, J = 6.4Hz) 2.099 (1H, s) 3.618 ( 3H, J = 6.4Hz) ▲ α ²⁵ _D ▼ ＝ ＋ 7.07 ° (neat).

[Example 4] Production of 2-((S) -2-methylbutoxy) -5- (p-dodecyloxyphenyl) pyrazine 2-chloro-5- (p-octyloxyphenyl) pyrazine used in Example 1 2-chloro-5 instead of
The title compound was prepared in the same manner except that-(p-dodecyloxyphenyl) -2-pyrazine was used.

Elemental analysis C H N Found: 76.30% 10.06% 6.56% _{Calculated: 76.01 9.92 6.57 (C 27 H} 42 N 2 as _{O 2) IR (KBr) cm} -1: 2950,2910,2840,1600,1460,1335 ,
1290, 1245, 1175, 1050, 1010, 990, 825 [Example 5] 2-((S) -3-methylpentyloxy) -5- (p
Preparation of -dodecyloxyphenyl) pyrazine The title compound was prepared in the same manner except that the following (S) -3-methylpentanol was used instead of (S) -2-methylbutanol used in Example 4. .

Elemental analysis C H N Found 76.56% 9.99% 6.45% Calculated _{76.32 10.06 6.36 (C 28 H 44} N 2 as _{O 2) IR (KBr) cm} -1: 2930,2860,1615,1470,1300,1250,
1180, 1020, 835 Production of (S) -3-methylpentanol (S) -2-Methylbutyl bromide [α = + 3.90 (nea
t)] 37.8 g, Mg 6.9 g and 100 ml of ether were added to a Grineer reagent, and 32.7 g of methyl orthoformate was added to 40 m of ether.
The solution was added dropwise over 40 minutes. After heating under reflux for 5 hours, ether was distilled off, 200 ml of 3N hydrochloric acid and 50 ml of concentrated hydrochloric acid were added under ice cooling, and the mixture was heated under reflux for 1 hour. After extraction with ether (50 ml x 5), the ether solution was dried, and then fractionally distilled (boiling point: 115-120 ° C) to give (S) -3-methylpentanal 9.3 g (GC purity: 89.5).
%) Was obtained.

In a suspension of 0.63 g of LiAlH _{4 in} 30 ml of ether, the above (S)-
3-Methylpentanal was added dropwise. After stirring for 1 hour, 20 ml of water was added dropwise under ice cooling, 36 ml of 10% sulfuric acid was added, the ether layer was separated, and the aqueous layer was extracted with ether (50 ml × 2). After the ether solution was dried, it was fractionally distilled (boiling point: 142-150 ° C) and 3.37 g of (S) -3-methylpentanol (GC purity: 84.3
%, ▲ α ²² _D ▼ = + 8.44 °) was obtained.

[Example 6] 2-((S) -4-methylhexyloxy) -5- (p
Preparation of -dodecyloxyphenyl) pyrazine Instead of 2-chloro-5- (p-octyloxyphenyl) pyrazine used in Example 2, 2-chloro-5
The title compound was prepared in the same manner except that-(p-dodecyloxyphenyl) -2-pyrazine was used.

IR (KBr) cm ^-1 : 2950, 2910, 2840, 1600, 1460, 1330,
1260,1170,1045,1010,990,830 Elemental analysis C H N Found: 76.49% 10.08% 6.25% _{Calculated: 76.60 10.19 6.16 (C 29 H} 46 N 2 O 2 as a) [Example 7] 2- ( (S) -8-Methyldecyloxy) -5- (p-
Preparation of dodecyloxyphenyl) pyrazine 2-chloro-5 was used instead of 2-chloro-5- (p-octyloxyphenyl) pyrazine used in Example 3.
The title compound was prepared in the same manner except that-(p-dodecyloxyphenyl) -2-pyrazine was used.

IR (KBr) cm ^-1 : 2950, 2920, 2850, 1605, 1465, 1340,
1260, 1175, 1055, 1015, 1000, 830 Elemental analysis CHN Actual value: 77.80% 10.67% 5.47% Calculated value: 77.60 10.66 5.48 (as C ₃₃ H ₅₄ N ₂ O ₂ ) [Example 8] 2- ( (S) -1-Methylheptyloxy) -5- (p
Preparation of -dodecyloxyphenyl) pyrazine The title compound was prepared in the same manner except that (S) -2-octanol was used instead of (S) -2-methylbutanol used in Example 4.

C H N measured value 77.13% 10.43% 6.05% calculated value 76.88 10.32 5.98 (as C ₃₀ H ₄₈ N ₂ O ₂ ) IR (KBr) cm ^-1 : 2950, 2910, 2845, 1605, 1465, 1295,
1245, 1175, 1015, 835 [Example 9] Preparation of 2-((S) -2-methylbutoxy) -5- (p-octanoyloxyphenyl) pyrazine 5- (p-methoxyphenyl) -2-chloro 7 g of pyrazine
Was mixed with 100 ml of 48% hydrobromic acid and 100 ml of acetic acid and heated under reflux for 6 hours. After concentrating under reduced pressure, 200 ml of ether was added to a black-brown solid obtained by adding 200 ml of water, and the insoluble portion was removed by filtration. The yellow crystals obtained by concentrating the ether solution to dryness were recrystallized from methanol (50 ml) to give 4.2 g of 5-
(P-Hydroxyphenyl) -2-bromopyrazine (MS
From the analysis, it was confirmed that a small amount of chloro form was mixed).

IR (KBr) cm ^-1 : 3300, 1600, 1580, 1500, 1445, 1430, ¹
320, 1300, 1270, 1210, 1160, 1110, 1010, 830, 77
2.0 g of 5- (p-hydroxyphenyl) -2-bromopyrazine was added to a solution of 6.8 g of S-2-methylbutanol in which 0.67 g of Na, 550, and 490 Na was dissolved, and the mixture was stirred at 100 ° C. for 4 hours. After acidifying with dilute hydrochloric acid (concentrated hydrochloric acid 13 ml + water 20 ml), ether (40 ml x
Extracted in 3). The crystals obtained by concentrating the ether solution were subjected to silica gel column chromatography (developing solution: ether 3
% -Hexane) to give 5- (p-hydroxyphenyl) -2-((S) -2-methylbutoxy) pyrazine (1.96 g).

IR (KBr) cm ^-1 : 2950, 2870, 1600, 1505, 1460, 1335,
1290, 1255, 1170, 1050, 1010, 1000, 825 The above compound was esterified with octanoyl chloride to obtain the title compound.

C H N measured value 71.99% 8.50% 7.33% calculated value 71.84 8.39 7.29 (as C ₂₃ H ₃₂ N ₂ O ₃ ) IR (KBr) cm ^-1 : 2950, 2920, 2850, 1750, 1455, 1330,
1205, 1165, 1135, 1005, 845 [Example 10] 2-((S) -2-methylbutyloxy) -5- (p-
Preparation of dodecanoyloxyphenyl) pyrazine 5- (p-hydroxyphenyl) -2-((S) -2-methylbutoxy) pyrazine obtained by the same method as in Example 9 was esterified with dodecanoyl chloride to give the title compound. Got

C H N measured 73.53% 9.11% 6.47% Calculated 73.60 9.15 6.35 (as C ₂₇ H ₄₀ N ₂ O ₃ ) IR (KBr) cm ^-1 : 2940, 2900, 2830, 1740, 1450, 1320,
1280, 1200, 1160, 1120, 1100, 1000, 900, 840 [Example 11] 2-((S) -2-methylbutoxy) -5- [p-
Preparation of (p'-heptylbenzoyloxy) phenyl] pyrazine 5- (p-hydroxyphenyl) -2-((S) -2-methylbutoxy) pyrazine obtained by the same method as in Example 9 was converted into p-chloride. Esterification with heptylbenzoyl gave the title compound.

CHN Measured value 76.02% 7.89% 6.13% Calculated value 75.62 7.88 6.08 (as C ₂₉ H ₃₆ N ₂ O ₃ ) IR (KBr) cm ^-1 : 2950, 2920, 2850, 1730, 1600, 1460,
1280, 1260, 1210, 1180, 1060, 1000, 870 [Example 12] 2-((S) -2-methylbutyloxy) -5- (p-
Preparation of dodecyloxyphenyl) pyrazine Instead of 2-chloro-5- (p-octyloxyphenyl) pyrazine used in Example 1, 2-chloro-5- (p
The title compound was obtained in the same manner except that -dodecylphenyl) pyrazine was used.

C H N Measured value 78.84% 10.39% 6.87% Calculated value 79.00 10.30 6.82 (as C ₂₇ H ₄₂ N ₂ O) IR (KBr) cm ^-1 : 2950, 2920, 2850, 1460, 1340, 1290,
1170, 1050, 1010 [Example 13] 2-((S) -4-methylhexyloxy) -5- (p
Preparation of -dodecylphenyl) pyrazine Instead of 2-chloro-5- (p-octyloxyphenyl) pyrazine used in Example 2, 2-chloro-5- (p
The title compound was obtained in the same manner except that -dodecylphenyl) pyrazine was used.

CHN Measured value 79.13% 10.41% 6.32% Calculated value 79.39 10.57 6.39 (as C ₂₉ H ₄₆ N ₂ O) IR (KBr) cm ^-1 : 2950, 2910, 2850, 1610, 1460, 1330,
1140, 1020, 1010 [Example 14] Production of 2-octyloxy-5- (p- (S) -2-methylbutoxyphenyl) pyrazine 44.1 g of KOH was dissolved in a mixed solution of 1000 ml of ethanol and 15 ml of water. P-Hydroxyacetophenone in alkaline solution
145.6 g was added, then 172.7 g of (S) -2-methylbutyltoluenesulfonate was added, and the mixture was heated under reflux for 7 hours. Ethanol was distilled off under reduced pressure, 700 ml of water was added, and the mixture was extracted with ether (200 ml × 3). The ether extract was washed with 10% aqueous caustic soda solution and concentrated to obtain a brown liquid, which was distilled under reduced pressure to obtain 100 g of p- (S) -2-methylbutoxyacetophenone (boiling point 145 ° C./4 mmHg).

To a solution prepared by dissolving 50 g of selenium dioxide in a mixed solvent of 640 ml of dioxane and 27 ml of water, 100 g of p- (S) -2-methylbutoxyacetophenone was added, and after heating under reflux for 7.5 hours, a black precipitate (Se) was filtered off. Separated, the filtrate was concentrated under reduced pressure to obtain 115 g of p- (S) -2-methylbutoxyphenylglyoxal hydrate as a yellow liquid.

IR (liquid film) cm ^-1 : 3700 ~ 3000, 3000 ~ 2800, 1670, 159
0, 1500 115 g of this glyoxal hydrate, glycinamide hydrochloride
An aqueous caustic soda solution (45 g of NaOH, 116 ml of water) was added dropwise (1 hour) to a mixture of 64 g of methanol and 1.6 at 40 ° C. Then, the temperature was gradually raised (from -40 ° C to 10 ° C over 3 hours), and then the mixture was stirred at 10 ° C for 12 hours. The precipitate obtained by acidification with hydrochloric acid was collected by filtration, washed thoroughly with water and dried to obtain 5
-(P- (S) -2-methylbutyloxyphenyl)-
42.3 g of a brown powder of 2-pyrazinol was obtained.

2-Chloro- (p- (S) -2 was prepared using the above-mentioned 5- (p- (S) -2-methylbutyloxyphenyl) -2-pyrazinol by the method described in JP-A-61-129171.
-Methylbutyloxyphenyl) pyrazine.

Using the above-mentioned 2-chloro- (p- (S) -2-methylbutoxyphenyl) pyrazine and sodium octyl oxide as starting materials, the title 2-octyloxy-5- (p- (was prepared in the same manner as in Example 1. S) -2-Methylbutoxyphenyl) pyrazine was obtained.

C H N Found 74.91% 9.50% 7.23% Calculated _{74.56 9.25 7.56 (C 23 H 34} N 2 as _{O 2) IR (KBr) cm} -1: 2950,2920,2850,1600,1505,1460,
1350, 1290, 1255, 1235, 1170, 1045, 1010, 980, 82
5,610 [Example 15] Production of 2-nonyloxy-5- (p- (S) -2-methylbutoxyphenyl) pyrazine The 2-chloro- (p- (S) -2- obtained in Example 14 was used. The title 2-nonyloxy-5- (p- (S) -2-methylbutoxyphenyl) pyrazine was obtained in the same manner as in Example 1 by using methylbutoxyphenyl) pyrazine and sodium nonyloxide as raw materials.

CHN Measured value 75.02% 9.59% 7.28% Calculated value 74.96 9.44 7.28 (as C ₂₄ H ₃₆ N ₂ O ₂ ) IR (KBr) cm ^-1 : 2940, 2900, 2840, 1600, 1500, 1455,
1340, 1290, 1255, 1240, 1165, 1045, 825 [Example 16] Production of 2-dodecyloxy-5- (p- (S) -2-methylbutoxyphenyl) pyrazine Obtained in Example 14 2- Using the chloro- (p- (S) -2-methylbutyloxyphenyl) pyrazine and sodium dodecyl oxide as starting materials, the title 2-dodecyloxy-5- (p- (S)-was prepared in the same manner as in Example 1. Two
-Methylbutoxyphenyl) pyrazine was obtained.

CHN Measured value 76.04% 10.04% 6.54% Calculated value 76.01 9.92 6.57 (as C ₂₇ H ₄₂ N ₂ O ₂ ) IR (KBr) cm ^-1 : 2950, 2900, 2850, 1600, 1500, 1460,
1340, 1255, 1240, 1165, 1050, 1010, 820 [Example 17] Preparation of 2-octyloxy-5- (p- (S) -4-methylhexyloxyphenyl) pyrazine Used in Example 14 (S ) -2-Methylbutyl =
The title compound was obtained in the same manner except that (S) -4-methylhexyl = p-toluenesulfonate was used instead of p-toluenesulfonate.

CHN Measured value 75.36% 9.58% 7.03% Calculated value 75.33 9.61 7.03 (as C ₂₅ H ₃₈ N ₂ O ₂ ) IR (KBr) cm ^-1 : 2920, 2850, 1610, 1510, 1465, 1350,
1300, 1245, 1180, 835 [Example 18] Preparation of 2-dodecyloxy-5- (p- (R) -2-octyloxyphenyl) pyrazine 5- (p-hydroxyphenyl) -2-bromopyrazine and sodium 1.50 g of 5- (p-hydroxyphenyl) -2-dodecyloxypyrazine obtained from dodecyl oxide
And (S) -2-octyl = p-toluenesulfonate 1.
Add 28 g to 10 ml of dimethylformamide (DMF), then
Stirred at 100 ° C. for 3 hours in the presence of 0.58 g K ₂ CO ₃ . Next, 100 ml of water was added, and the mixture was extracted with ether (50 ml × 5). Yellow crystals obtained by washing the ether solution with water, drying, and concentrating
After dissolving 2.0 g in hexane and filtering insoluble matter, silica gel column chromatography (developing solution: hexane 9:
The crystals obtained by ethyl acetate 1) were recrystallized from hexane to obtain 0.70 g of the title compound.

C H N Found 76.91% 10.25% 5.97% Calculated _{76.88 10.32 5.98 (C 30 H 48} N as _{2 O 2) IR (KBr)} cm -1: 2920,2850,1615,1520,1470,1350,
1265, 1250, 1180, 1020, 840, 820 [Example 19] Production of 2-dodecyloxy-5- (p- (S) -4-methylhexyloxyphenyl) pyrazine (S) -used in Example 18 Instead of 2-octyl = p-toluenesulfonate, (S) -4-methylhexyl = p
-The title compound was obtained in the same manner except that toluene sulfonate was used.

CHN Measured value 76.70% 10.31% 6.20% Calculated value 76.61 10.20 6.16 (as C ₂₉ H ₄₆ N ₂ O ₂ ) IR (KBr) cm ^-1 : 2925, 2850, 1610, 1510, 1465, 1355,
1300, 1245, 1180, 1020, 835 [Example 20] Preparation of 2-octyloxy-5- (p- (S) -8-methyldecyloxyphenyl) pyrazine Instead of sodium dodecyl oxide used in Example 18, The title compound was obtained in the same manner except that sodium octyl oxide was replaced by (S) -2-octyl = p-toluenesulfonate (S) -8-methyldecyl = p-toluenesulfonate.

CHN Measured value 76.43% 10.45% 6.23% Calculated value 76.60 10.20 6.16 (as C ₂₉ H ₄₆ N ₂ O ₂ ) IR (KBr) cm ^-1 : 2950, 2920, 2850, 1605, 1465, 1340,
1295, 1245, 1180, 1015, 835 [Example 21] Production of 2-dodecyloxy-5- (p- (S) -8-methyldecyloxyphenyl) pyrazine (S) -4-used in Example 19 The title compound was obtained in the same manner except that (S) -8-methyldecyl = p-toluenesulfonate was used instead of methylhexyl = p-toluenesulfonate.

CHN Measured value 77.87% 10.73% 5.53% Calculated value 76.60 10.66 5.48 (as C ₃₃ H ₅₄ N ₂ O ₂ ) IR (KBr) cm ^-1 : 2930, 2850, 1610, 1470, 1340, 1300,
1250, 1180, 1020, 840 [Example 22] 2-octyloxy-5- [p- (p '-(S) -2-
Preparation of methylbutoxybenzoyloxy) phenyl] pyrazine 5- (p-hydroxyphenyl) -2-octyloxypyrazine was obtained from 5- (p-hydroxyphenyl) -2-bromopyrazine in the same manner as in Example 9. Then p-
Esterification with ((S) -2-methylbutoxybenzoyl) chloride gave the title compound.

IR (KBr) cm ^-1 : 2950, 2920, 2850, 1720, 1600, 1500,
1460, 1250, 1210, 1160, 1070, 1000, 870, 840, 760 Example 23 Preparation of 2-heptyl-5- (p- (S) -2-methylbutoxyphenyl) pyrazine Obtained in Example 14 5- (p- (S) -2-methylbutoxyphenyl) -2-chloropyrazine was reacted with heptylmagnesium bromide in the presence of ferric chloride and tetrabutylammonium chloride.
-129171), and the title compound was obtained.

IR (KBr) cm ^-1 : 2950, 2910, 2850, 1600, 1475, 1240,
1170, 1015, 825 [Example 24] Production of 2-octyl-5- (p- (S) -2-methylbutoxyphenyl) pyrazine 5- (p- (S) -2- obtained in Example 14 Methylbutoxyphenyl) -2-chloropyrazine was reacted with octylmagnesium bromide in the presence of ferric chloride and tetrabutylammonium chloride (Japanese Patent Laid-Open No. Sho 61-61).
-129171), and the title compound was obtained.

IR (KBr) cm ^-1 : 2950, 2900, 2840, 1600, 1475, 1460,
1240, 1165, 1015, 820 [Example 25] Production of 2-dodecyl-5- (p- (S) -2-methylbutyloxyphenyl) pyrazine 5- (p- (S)) obtained in Example 14 2-Methylbutoxyphenyl) -2-chloropyrazine was reacted with dodecylmagnesium bromide in the presence of ferric chloride and tetrabutylammonium chloride (Japanese Patent Laid-Open No. Sho 61-61).
-129171), and the title compound was obtained.

IR (KBr) cm ^-1 : 2950, 2900, 2840, 1600, 1480, 1460,
1240, 1030, 820 [Example 26] Production of 2-octyl-5- (p- (S) -4-methylhexylphenyl) pyrazine 5- (p- (S) -2-methyl used in Example 24 Butoxyphenyl) -2-chloropyrazine instead of 5- (p
5- (p-methoxyphenyl) -2 obtained in the same manner except that -methoxyphenyl) -2-chloropyrazine was used.
-Octylpyrazine was hydrolyzed as in Example 9 to give 5
-(P-Hydroxyphenyl) -2-octylpyrazine was obtained.

IR (KBr) cm ^-1 : 2920, 2850, 1605, 1480, 1470, 1260,
1150, 1020, 830 The title compound was prepared in the same manner as in Example 18 from the above 5- (p-hydroxyphenyl) -2-octylpyrazine and (S) -4-methylhexyl = p-toluenesulfonate. .

CHN Measured value 78.32% 9.92% 7.37% Calculated value 78.49 10.01 7.32 (as C ₂₅ H ₃₈ N ₂ O) IR (KBr) cm ^-1 : 2970, 2925, 2850, 1610, 1485, 1470,
1300, 1270, 1250, 1180, 1025, 850 [Example 27] Preparation of 2-dodecyl-5- (p- (S) -4-methylhexyloxyphenyl) pyrazine 5- (p- used in Example 25 Instead of (S) -2-methylbutoxyphenyl) -2-chloropyrazine, 5- (p
5- (p-methoxyphenyl) -2-dodecylpyrazine was obtained in the same manner except that -methoxyphenyl) -2-chloropyrazine was used, and then hydrolyzed in the same manner as in Example 9 to give 5- (p-hydroxy). Phenyl) -2-dodecylpyrazine was obtained.

IR (KBr) cm ^-1 : 2920, 2850, 1610, 1485, 1465, 1260,
1150, 1020, 830, 715 The title compound was prepared in the same manner as in Example 18 from 5- (p-hydroxyphenyl) -2-dodecylpyrazine and (S) -4-methylhexyl = p-toluenesulfonate. .

C H N Found 79.30% 10.68% 6.46% Calculated _{79.40 10.57 6.39 (C 29 H 46} N 2 O ^{as) IR (KBr) cm -1:} 2970,2930,2850,1610,1485,1465,
1275, 1250, 1175, 1020, 830 [Example 28] Production of 2-ethyl-5- [p- (p '-(S) -2-methylbutoxybenzoyloxy) phenyl] pyrazine In the same manner as in Example 23 The obtained 5- (p-methoxyphenyl) -2-ethylpyrazine was hydrolyzed in the same manner as in Example 9 to obtain 5- (p-hydroxyphenyl) -2-ethylpyrazine. Then, esterification was carried out to produce the title compound.

IR (KBr) cm ^-1 : 2950, 2920, 2850, 1720, 1600, 1500,
1460, 1250, 1200, 1160, 1070, 870, 760 [Example 29] Preparation of 2-undecyl-5- [p- (p '-(S) -2-methylbutoxybenzoyloxy) phenyl] pyrazine Example 23 5- (p-methoxyphenyl) -2-undecylpyrazine obtained in the same manner as in Example 5 was hydrolyzed in the same manner as in Example 9 to give 5- (p-hydroxyphenyl) -2.
-Undecyl pyrazine was obtained. Then, esterification was carried out to produce the title compound.

IR (KBr) cm ^-1 : 2950, 2920, 2850, 1720, 1600, 1500,
1480, 1250, 1200, 1160, 1070, 870, 840, 760 Table 1 shows the phase transition temperatures of the obtained compounds.

Note: In Table 1, “C” indicates a crystalline phase, “SmC ^* ” indicates a chiral smectic C phase, “SmA” indicates a smectic A phase, and “Ch” cholesteric phase.

Further, "-" indicates that the compound does not exhibit the phase by itself, and "exhibit" indicates that the phase exhibits by itself.
In addition, the number shown indicates the transition temperature from the phase in the column in which the number is written to the phase in the column in the column to the right of that column, and the number in parentheses indicates the transition in the opposite direction. Indicates temperature.

[Reference Example 1] The compound of the present invention has liquid crystal properties even in a mixed system, and due to the decrease in melting point, SmC
An example showing * is given below.

2-((S) -4-methylhexyloxy-5- (p-octyloxyphenyl) pyrazine obtained in Example 2 and 2-((S) -8-methyldecyloxy) obtained in Example 3
The phase diagram of the mixed system of -5- (p-octyloxyphenyl) pyrazine is shown in FIG. The measured values are from the temperature decreasing process.

As can be seen from FIG. 1, the liquid crystal composition obtained by mixing 1 part by weight of the compound of Example 2 and 1 part by weight of the compound of Example 3 was 30 ° C.
SmC * phase is also shown in the vicinity.

USE EXAMPLE 1 A mixed liquid crystal composition (weight composition ratio 1: 1) composed of the compound obtained in Example 2 and the compound obtained in Example 3 shown in Reference Example 1 above was subjected to a rubbing treatment. The electro-optical cell was assembled so that the cell thickness was 2 μm by heat-sealing between the two substrates having the transparent electrodes.

This cell is sandwiched between two polarizing plates that are orthogonal to each other.
It was confirmed that when AC electrolysis of 10 V and 0.5 Hz was applied, the display state changed depending on the direction of electrolysis.

At 30 ° C, the response when AC electrolysis of ± 15 V was applied was 3.5 ms, and the contrast during multiplex driving was 1:10.

[Reference Example 2] 2-((S) -4-methylhexyloxy) -5- (p-dodecyloxyphenyl) pyrazine obtained in Reference Example 6 and 2-((S) -8 obtained in Example 3) The phase diagram of the mixed system of -methyldecyloxy) -5- (p-octyloxyphenyl) pyrazine is shown in FIG. The measured values are from the temperature decreasing process.

As can be seen from FIG. 2, the liquid crystal composition obtained by mixing 1 part by weight of the compound of Example 5 and 1 part by weight of the compound of Example 3 shows the SmC * phase even at around 30 ° C.

USE EXAMPLE 2 A mixed liquid crystal composition (weight composition ratio consisting of the compound obtained in Example 5 and the compound obtained in Example 3 shown in Reference Example 2 above)
1: 1) was heat-sealed between two substrates having a rubbing-processed transparent electrode, and an electro-optical cell was assembled so that the cell thickness was 2 μm.

This cell is sandwiched between two polarizing plates that are orthogonal to each other.
It was confirmed that the display state changed depending on the direction of the electric field when an AC electric field of 10 V and 0.5 Hz was applied.

Moreover, the response when AC electrolysis of ± 15 V was applied at 30 ° C. was 3.5 ms, and the contrast during multiplex driving was 1:10.

[Effects of the Invention] The pyrazine derivative provided by the present invention exhibits the properties of a ferroelectric liquid crystal and can be used as a component of a ferroelectric liquid crystal composition.

Further, by mixing the liquid crystal compound of the present invention, a decrease in melting point can be achieved, and a liquid crystal composition exhibiting an SmC * phase at room temperature or lower can be provided.

[Brief description of drawings]

1 and 2 show examples of phase diagrams (cooling process) of a system in which the pyrazine derivative of the present invention is mixed.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuko Yokoo 8-1 Goi Minami Coast, Ichihara City, Chiba Ube Industries, Ltd. Chiba Research Institute (72) Inventor Takashi Honma 8 Goi Minami Coast, Ichihara City, Chiba Prefecture Number one Uchikosan Co., Ltd. Chiba Research Institute (72) Inventor Kazuo Aoki 3-5 Yamato, Suwa City, Nagano Prefecture Seiko Epson Corporation (72) Inventor Fusako Ikegami 3-3 Yamato, Suwa City, Nagano Prefecture No. 5 within Seiko Epson Corporation

Claims (3)

[Claims] 1. General formula (I): [Wherein R ¹ is an alkyl group having 1 to 18 carbon atoms, an alkoxy group, an acyloxy group, a p-alkylbenzoyloxy group, or a p-alkoxybenzoyloxy group, and
R ² is an alkyl group or an alkoxy group having 1 to 18 carbon atoms, and at least one of R ¹ and R ² is an optically active group]. 2. An optically active group is (s) -2-methyl-butoxy group, (s) -4-methylhexyloxy group, (R).
A group selected from the group consisting of a 2-octyloxy group, a (S) -2-octyloxy group, and a (s) -8-methyldecyloxy group. Pyrazine derivative of. 3. The optically active group is (s) -2-methylbutyl group, (s) -4-methylhexyl group, (R) -2-octyl group, (S) -2-octyl group, and (S). ) -8-
The pyrazine derivative according to claim 1, which is a group selected from the group consisting of methyldecyl groups.