JPH0830032B2 - Substituted naphthalene compound - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a novel substituted naphthalene compound, and more specifically, the present invention relates to a novel substituted naphthalene compound which is particularly useful as a ferroelectric liquid crystal substance.

TECHNICAL BACKGROUND OF THE INVENTION AND PROBLEMS THEREOF Conventionally, CRT devices have been most widely used as display devices for OA equipment and the like.

In the field of equipment having a display device such as OA equipment, there has been an increasing demand in recent years for downsizing and weight reduction of the equipment, or for a larger and thinner display device. For this reason, various new display devices have been developed in place of the conventional CRT devices in accordance with the respective uses or requests. For example, such display devices include liquid crystal displays, plasma displays, LED displays, EL displays, ECD displays, and the like.

Of these display devices, the liquid crystal display is
Basically, it is a device that gives an electric signal to a switching element using a liquid crystal compound, changes the state of the liquid crystal compound in the switching element, controls the shielding and transmission of light, and makes the electric signal visible. OA mentioned above
Not only has it been used as a display device for devices, it has already been put to practical use as a display device for digital watches, portable games, and the like, and in recent years, it has begun to be used as a display device for moving images such as small televisions.

In a display device using a liquid crystal compound as described above, various driving methods are already known. For example, currently used liquid crystal display device driving methods include:
There is a TN (twisted nematic) mode. In the TN mode, display is performed using the dielectric anisotropy of molecules in a nematic phase of a liquid crystal compound, and a display device is driven by energy proportional to the square of an externally applied electric field (f∞). E ^2).

However, in order to change the displayed image in a switching element that adopts this method,
Since it is necessary to change the positions of the molecules of the liquid crystal compound, there is a problem that the driving time becomes long and the voltage required for changing the positions of the molecules of the liquid crystal compound, that is, the power consumption also increases. In such a switching element, since the switching threshold characteristic is not so good, if the switching operation is performed by changing the molecular position at high speed, the leakage voltage is applied to the non-display image portion,
There is a problem that the display contrast is significantly reduced.

Since the conventional TN mode display method has the above-mentioned problems, a display device using the TN mode is particularly suitable for a large screen display device or a moving image such as a small digital television. Is not suitable as a display device.

In addition, a display device using an STN (super twist nematic) mode, which has improved switching threshold characteristics in the TN mode as described above, is used. By using such an STN mode, the switching threshold characteristic is improved, so that the contrast of the display device is improved. However, this method is also the same as TN mode in that it uses dielectric anisotropy, and therefore the switching time is long, so that it is a display device for large screens or a display device for moving images such as small digital televisions. As a result, it does not have sufficient characteristics.

On the other hand, the organic compounds synthesized by RBMeyer et al. In 1975 showed ferroelectricity, and in 1980, RBMeyer et al., Filled these ferroelectric liquid crystal compounds in a cell with a small gap to obtain ferroelectricity. The possibility of using the liquid crystal compound as an optical switching element, that is, a display device was suggested.

The switching element using the ferroelectric liquid crystal compound as described above, unlike the switching element using the TN mode or STN mode, can function as a switching element simply by changing the orientation direction of the molecules of the liquid crystal compound. , Switching time is greatly reduced.
Further, since the value of Ps × E given by the spontaneous polarization (Ps) and the electric field strength (E) of the ferroelectric liquid crystal compound is the effective energy strength for changing the orientation direction of the molecules of the liquid crystal compound, the power consumption is reduced. Will be much less. Since such a ferroelectric liquid crystal compound has two stable states depending on the direction of the applied electric field, that is, bistability, the switching threshold characteristic is also very good, and it is suitable for large screens or moving images. It is particularly suitable as a display device for.

When such a ferroelectric liquid crystal compound is used in an optical switching element, such a ferroelectric liquid crystal compound is
Characteristics such as that the operating temperature range is around room temperature, the operating temperature range is wide, the switching speed is high, and the switching threshold voltage is within an appropriate range are required. Of these, the operating temperature range is a particularly important characteristic when using a ferroelectric liquid crystal compound,
Although other properties are very good, many ferroelectric liquid crystal compounds cannot be used because the operating temperature range and the operating temperature range do not match (for example, RB Meyer et a
l, Journal de Phys. 36 volumes L-
69, (1975)).

Furthermore, the proceedings of the 11th liquid crystal debate published by Masaaki Taguchi, Takamasa Harada, etc., page 168 (1985), JP-A-6
In 2-10045, etc., for example, a ferroelectric liquid crystal compound having a naphthalene ring is disclosed, and the liquid crystal compound disclosed therein is a compound having relatively high practicability in terms of operating temperature range and the like. However, it is difficult to say that all properties other than the operating temperature of the liquid crystal compound such as the stability of the compound are satisfied, for example, a substituent is directly bonded to the naphthalene ring through an ester bond, and there is room for further improvement. there were.

Although the ferroelectric liquid crystal compound has been mainly described above, it is naturally required that the substituted naphthalene compound is excellent in properties such as chemical stability even when it is used for other purposes.

OBJECT OF THE INVENTION It is an object of the present invention to provide a novel substituted naphthalene compound.

Another object of the present invention is to provide a novel substituted naphthalene compound which is highly useful as a liquid crystal substance.

SUMMARY OF THE INVENTION The substituted naphthalene compound of the present invention is characterized by being represented by the following formula [I].

However, in the above formula [I], R ¹ has 1 to 18 carbon atoms.
R ² represents an alkyl group having 1 to 18 carbon atoms, and X represents either a group represented by —OCH ₂ — or a group represented by —CH ₂ CH ₂ —. , N is 0 or 1
Is.

Such a substituted naphthalene compound can be effectively used as a liquid crystal compound, for example, when R ² is an alkyl group having 2 or more carbon atoms.

Specific Description of the Invention The substituted naphthalene compound according to the present invention will be specifically described below.

The substituted naphthalene compound according to the present invention can be represented by the following formula [I].

However, in the above formula [I], R ¹ has 1 to 18 carbon atoms.
Represents an alkyl group. In particular, R ¹ is preferably an alkyl group having 6 to 16 carbon atoms.

In the above formula [I], R ² represents an alkyl group having 1 to 18 carbon atoms, particularly preferably an alkyl group having 1 to 7 carbon atoms.

Further, in the above formula [I], X is either a group represented by —OCH ₂ — or a group represented by —CH ₂ CH ₂ —.

 In the formula [I], n is 0 or 1.

Further, the substituted naphthalene compound according to the present invention is preferably a compound having optically active carbon represented by the following formula [II], which is an alkyl group having 2 or more carbon atoms in R ² in the above formula [I]. The substituted naphthalene compound represented by the following formula [II] is particularly effective as a liquid crystal compound.

However, in the above formula [II], R ¹ is the above formula [I]
Similarly, represents an alkyl group having 1 to 18 carbon atoms. Especially R ¹
Is preferably an alkyl group having 6 to 16 carbon atoms,
Furthermore, when using this compound as a liquid crystal substance,
The above R ¹ is preferably a linear alkyl group having 8 to 12 carbon atoms.

R ³ represents an alkyl group having 1 to 18 carbon atoms. In particular, R ³ is preferably an alkyl group having 2 to 8 carbon atoms, and when used as a liquid crystal substance, R ³ is particularly preferably an ethyl group or a hexyl group. Further, when R ³ is an ethyl group, n in the above formula [II] is preferably 1, and when it is a hexyl group, n is preferably 0.

Furthermore, in the equation [II], X is -OCH ₂ - is any group of the groups represented by - group or -CH ₂ represented by CH _2.

Therefore, when the substituted naphthalene compound of the present invention is classified according to the kind of the substituent X and the like, the following formulas [Ia] and [II-a]
And a compound represented by [III-a] and [I-
b], [II-b], and [III-b].

In addition, the above formulas [I-a], [II-a] and [III-
a] and [Ib], [II-b] and [III-
In b], R ¹ and R ^3, R ¹ in the formula [I]
And R ³ have the same meaning.

The above formulas [Ia], [II-a] and [II]
Ia] and [Ib], [II-b] and [III-
Among the compounds represented by b], examples of compounds having particularly high efficacy are shown below.

2- [4 '-(R-2 "-methylpropylcarbonyl) phenylmethyloxy] -6-decyloxynaphthalene, 2- [2'-{4"-(R-2-methylpropylcarbonyl) phenyl} ethyl] -6-decyloxynaphthalene.

2- [4 '-(R-2 "-methylbutylcarbonyl)
Phenylmethyloxy] -6-decyloxynaphthalene, 2- [4 '-(R-2 "-methylpentylcarbonyl) phenylmethyloxy] -6-decyloxynaphthalene, 2- [4'-(R-2"- Methylheptylcarbonyl) phenylmethyloxy] -6-decyloxynaphthalene, 2- [4 ′-(R-2 ″ -methyloctylcarbonyl) phenylmethyloxy] -6-decyloxynaphthalene, 2- [4 ′-(R -2 "-methylnonylcarbonyl)
Phenylmethyloxy] -6-decyloxynaphthalene, 2- [4 ′-(R-2 ″ -methylbutylcarbonyl)
Phenylmethyloxy] -6-pentyloxynaphthalene, 2- [4 '-(R-2 "-methylbutylcarbonyl)
Phenylmethyloxy] -6-heptyloxynaphthalene, 2- [4 '-(R-2 "-methylbutylcarbonyl)
Phenylmethyloxy] -6-octyloxynaphthalene, 2- [4 '-(R-2 "-methylbutylcarbonyl) phenylmethyloxy] -6-nonyloxynaphthalene, 2- [4'-(R-2"- Methylbutylcarbonyl)
Phenylmethyloxy] -6-undecyloxynaphthalene, 2- [4 '-(R-2 "-methylbutylcarbonyl)
Phenylmethyloxy] -6-dodecyloxynaphthalene, 2- [4 '-(R-2 "-methylbutylcarbonyl)
Phenylmethyloxy] -6-tridecyloxynaphthalene, 2- [4 '-(R-2 "-methylbutylcarbonyl)
Phenylmethyloxy] -6-tetradecyloxynaphthalene, 2- [4 '-(R-2 "-methylbutylcarbonyl)
Phenylmethyloxy] -6-pentadecyloxynaphthalene, 2- [4 '-(R-2 "-methylbutylcarbonyl)
Phenylmethyloxy] -6-hexadecyloxynaphthalene, 2- [4 '-(R-2 "-methylbutylcarbonyl)
Phenylmethyloxy] -6-heptadecyloxynaphthalene, 2- [4 '-(R-2 "-methylbutylcarbonyl)
Phenylmethyloxy] -6-octadecyloxynaphthalene.

2- [4 '-(R-1 "-methylheptylcarbonyl) phenylmethyloxy] -6-pentyloxynaphthalene, 2- [4'-(R-1" -methylheptylcarbonyl) phenylmethyloxy] -6 Heptyloxynaphthalene, 2- [4 '-(R-1 "-methylheptylcarbonyl) phenylmethyloxy] -6-octyloxynaphthalene, 2- [4'-(R-1" -methylheptylcarbonyl) phenylmethyloxy ] -6-nonyloxynaphthalene, 2- [4 '-(R-1 "-methylheptylcarbonyl) phenylmethyloxy] -6-undecyloxynaphthalene, 2- [4'-(R-1" -methylheptyl) Carbonyl) phenylmethyloxy] -6-dodecyloxynaphthalene, 2- [4 ′-(R-1 ″ -methylheptyl) Rubonyl) phenylmethyloxy] -6-tridecyloxynaphthalene, 2- [4 ′-(R-1 ″ -methylheptylcarbonyl) phenylmethyloxy] -6-tetradecyloxynaphthalene, 2- [4 ′-(R -1 "-methylheptylcarbonyl) phenylmethyloxy] -6-pentadecyloxynaphthalene, 2- [4 '-(R-1" -methylheptylcarbonyl) phenylmethyloxy] -6-hexadecyloxynaphthalene, 2- [4 ′-(R-1 ″ -methylheptylcarbonyl) phenylmethyloxy] -6-heptadecyloxynaphthalene, 2- [4 ′-(R-1 ″ -methylheptylcarbonyl) phenylmethyloxy] -6-octadecyl Oxynaphthalene.

2- [2 '-{4 "-(R-2-methylbutylcarbonyl) phenyl} ethyl] -6-decyloxynaphthalene, 2- [2'-{4"-(R-2-methylpentylcarbonyl) phenyl } Ethyl] -6-decyloxynaphthalene, 2- [2 '-{4 "-(R-2-methylhexylcarbonyl) phenyl} ethyl] -6-decyloxynaphthalene, 2- [2'-{4"- (R-2-methylheptylcarbonyl) phenyl} ethyl] -6-decyloxynaphthalene, 2- [2 ′-{4 ″-(R-2-methyloctylcarbonyl) phenyl} ethyl] -6-decyloxynaphthalene, 2- [2 '-{4 "-(R-2-methylnonylcarbonyl) phenyl} ethyl] -6-decyloxynaphthalene, 2- [2'-{4"-(R-2-methylbutyl Carbonyl) phenyl} ethyl] -6-pentyloxy-naphthalene.

2- [2 '-{4 "-(R-2-methylbutylcarbonyl) phenyl} ethyl] -6-hexyloxynaphthalene, 2- [2'-{4"-(R-2-methylbutylcarbonyl) phenyl } Ethyl] -6-heptyloxynaphthalene, 2- [2 '-{4 "-(R-2-methylbutylcarbonyl) phenyl} ethyl] -6-octyloxynaphthalene, 2- [2'-{4"- (R-2-Methylbutylcarbonyl) phenyl} ethyl] -6-nonyloxynaphthalene, 2- [2 ′-{4 ″-(R-2-methylbutylcarbonyl) phenyl} ethyl] -6-undecyloxynaphthalene 2- [2 '-{4 "-(R-2-methylbutylcarbonyl) phenyl} ethyl] -6-dodecyloxynaphthalene, 2- [2'-{4"-(R-2-methylbutane Rucarbonyl) phenyl} ethyl] -6-tridecyloxynaphthalene, 2- [2 '-{4 "-(R-2-methylbutylcarbonyl) phenyl} ethyl] -6-tetradecyloxynaphthalene, 2- [2 ′-{4 ″-(R-2-methylbutylcarbonyl) phenyl} ethyl] -6-pentadecyloxynaphthalene, 2- [2 ′-{4 ″-(R-2-methylbutylcarbonyl) phenyl} ethyl] -6-hexadecyloxynaphthalene, 2- [2 '-{4 "-(R-2-methylbutylcarbonyl) phenyl} ethyl] -6-heptadecyloxynaphthalene, 2- [2'-{4"-( R-2-Methylbutylcarbonyl) phenyl} ethyl] -6-octadecyloxynaphthalene.

2- [2 '-{4 "-(R-1-methylheptylcarbonyl) phenyl} ethyl] -6-hexyloxynaphthalene, 2- [2'-{4"-(R-1-methylheptylcarbonyl) phenyl } Ethyl] -6-heptyloxynaphthalene, 2- [2 '-{4 "-(R-1-methylheptylcarbonyl) phenyl} ethyl] -6-octyloxynaphthalene, 2- [2'-{4"- (R-1-methylheptylcarbonyl) phenyl} ethyl] -6-nonyloxynaphthalene, 2- [2 ′-{4 ″-(R-1-methylheptylcarbonyl) phenyl} ethyl] -6-decyloxynaphthalene, 2- [2 '-{4 "-(R-1-methylheptylcarbonyl) phenyl} ethyl] -6-undecyloxynaphthalene, 2- [2'-{4"-(R-1 Methyl [heptylcarbonyl) phenyl} ethyl] -6-dodecyloxynaphthalene, 2- [2 '-{4 "-(R-1-methylheptylcarbonyl) phenyl} ethyl] -6-tridecyloxynaphthalene, 2- [2 '-{4 "-(R-1-methylheptylcarbonyl) phenyl} ethyl] -6-tetradecyloxynaphthalene, 2- [2'-{4"-(R-1-methylheptylcarbonyl) phenyl} ethyl] -6-pentadecyloxynaphthalene, 2- [2 '-{4 "-(R-1-methylheptylcarbonyl) phenyl} ethyl] -6-hexadecyloxynaphthalene, 2- [2'-{4"-( R-1-methylheptylcarbonyl) phenyl {ethyl] -6-heptadecyloxynaphthalene, 2- [2 '-{4 "-(R-1-methyl Heptyl) phenyl} ethyl] -6-octadecyloxy naphthalene.

Next, the method for synthesizing the substituted naphthalene compound according to the present invention will be specifically described.

Among the substituted naphthalene compounds according to the present invention, those of the formula [II-
The compound represented by a] or [III-a] can be synthesized, for example, as follows.

First, an alkyl group corresponding to R ² is formed by a reaction of 4-halogenated methylbenzoic acid with an alcohol capable of forming an optically active carbon such as R-2-methylbutanol or R-1-methylheptanol according to a conventional method. An ester compound having is prepared.

Separately, one of the hydroxyl groups of 2,6-hydroxynaphthalene is alkylated to prepare 2-alkyloxy-6-hydroxynaphthalene having an alkyl group corresponding to R ¹ .

Next, the compound represented by the formula [II-a] can be obtained by reacting the above ester compound with 2-alkyloxy-6-hydroxynaphthalene.

In addition, the compound represented by the formula [Ia] is the above R
It can be synthesized, for example, by using 2-methylpropanol instead of 2-methylbutanol.

Further, the compound represented by the formula [II-b] or [III-b] is a lithium aluminum hydride obtained by converting 6-alkyloxy-2-carboxynaphthalene having an alkyl group corresponding to R ¹ prepared according to the above method. And the like to obtain 6-alkyloxy-2-hydroxymethylnaphthalene, and the 6-alkyloxy-2-hydroxymethylnaphthalene is oxidized with an oxidizing agent such as activated manganese dioxide to produce 2-alkyloxy-2-hydroxymethylnaphthalene. -Carbanyl-
6-alkyloxynaphthalene is obtained.

Separately, methyl (4-bromomethylphenylcarboxylate) and triphenylphosphine generated by the reaction of p-bromomethylbenzoic acid and methanol are reacted to obtain (4-methyloxycarbonyl) phenylmethylphosphonium bromide.

This (4-methyloxycarbonyl) phenylmethylphosphonium bromide and the above-mentioned 2-carbanyl-
2- [2 '-{4 "-(methyloxycarbonylphenyl) ethenyl] -6-alkyloxynaphthalene is obtained by reacting with 6-alkyloxynaphthalene, and this compound is obtained in the presence of a reducing catalyst such as a palladium catalyst. 2-by reducing hydrogen gas with
[2'-4 "- (methyloxy carbonyl phenyl) ethyl] -6-alkyl oxy naphthalene, then R-2-methylbutanol or R-1-methyl having an alkyl group corresponding to the naphthalene compound and R ² A compound represented by the formula [II-b] or [III-b] can be obtained by reacting with a branched alcohol such as heptanol.

Further, the compound represented by the formula [Ib] is the above R
It can be synthesized, for example, by using 2-methylpropanol instead of 2-methylbutanol.

The substituted naphthalene compound according to the present invention has a naphthalene ring and a phenylene ring in the molecule, and these rings are bonded with a specific group, so that the core portion of the molecule has a certain degree of rigidity. And the cohesive energy of the molecule is small. Therefore, in particular, the substituted naphthalene compound having an optically active carbon has a smectic phase near room temperature,
In particular, there are compounds that exhibit a smectic C phase, and such compounds have a spontaneous polarization value in the smectic C phase (P
s) and viscosity coefficient often show appropriate values for ferroelectric liquid crystal compounds. Therefore, the substituted naphthalene compound according to the present invention can be favorably used particularly as a ferroelectric liquid crystal compound.

The substituted naphthalene compound according to the present invention can be used not only as a ferroelectric liquid crystal compound as described above, but also as an intermediate for other drugs or agricultural chemicals.

Effect of the Invention The substituted naphthalene compound according to the present invention can be used, for example, as a liquid crystal compound.

Further, the substituted naphthalene compound according to the present invention includes a compound having optically active carbon, and such a compound is
Many have smectic layers near room temperature. Therefore,
Such a substituted naphthalene compound is particularly useful as a ferroelectric liquid crystal substance.

Further, the substituted naphthalene compound according to the present invention has high chemical stability such as hydrolysis resistance because the substituent is not directly bonded to the naphthalene ring by an ester bond.

Next, an example of the present invention will be shown, but the present invention is not limited to this example.

Example 1 Synthesis of 2- [4 '(R-2 "-methylbutylcarbonyl) phenylmethyloxy] -6-decyloxynaphthalene 1st stage 4-methylbenzoic acid 13.6 g (100 mmol), N-bromosuccinimide 17.8 g (100 mmol) and 1 g (4 mmol) of benzoyl peroxide were refluxed in 125 ml of carbon tetrachloride for 2 hours and, after cooling, the reaction product was taken.

The reaction product was recrystallized from methanol to obtain 14.6 g of 4-bromomethylbenzoic acid.

Second Step 1.08 g (5 mmol) of 4-bromobenzoic acid obtained in the first step, 0.61 ml (5.5 mmol) of R-2-methylbutanol and 0.1 ml of concentrated sulfuric acid were added to 40 ml of benzene, and 2
Refluxed for 5 hours.

After cooling, the reaction product was extracted with ether, and the extract was washed with an aqueous sodium hydrogen carbonate solution and further washed with water.

After washing with water, the extract was concentrated and column chromatography was used to obtain 0.8 g of 2'-methylbutyl-4-bromomethylbenzoate.

Phase 3 2,6-dihydroxynaphthalene 3.2 g (20 mmol) and tosylic acid decyl ester 3.12 g (10 mmol)
% KOH 0.66 g, ethanol 40 ml and water 0.2 ml were added to a mixed solution, and the mixture was stirred at 90 ° C. for 15 hours.

Next, the reaction solution was poured into water and neutralized with hydrochloric acid.

After neutralization, the reaction product was extracted with ether, the extract was washed with water, and concentrated.

From this concentrate using column chromatography 1.
6 g of 2-decyloxy-6-hydroxynaphthalene was isolated.

Fourth step 0.6 g (2 mmol) of 2-decyloxy-6-hydroxynaphthalene obtained in the above third step and 0.63 g (2.2 mmol) of 2'-methylbutyl-4-bromomethylbenzoate obtained in the second step And calcium carbonate 0.28g
(2 mmol) was added to 10 ml of dimethylformamide (DMF), stirred at 100 ° C. for 12 hours, and then added to water in the reaction solution.

Then, the reaction product was extracted with ether, washed with water, and concentrated.

The reaction product was separated from this concentrated liquid by column chromatography and recrystallized from hexane to obtain 0.27 g of white needle crystals.

As a result of analysis, this needle-shaped crystal was 2- [4 ′ (R-2 ″-
Methylbutylcarbonyl) phenylmethyloxy] -6
-Confirmed to be decyloxynaphthalene. Melting point: 89 ° C Figure 1 shows the ¹ H-NMR spectrum of this compound (270MHz, CD
(Measured with Cl).

As apparent from FIG. 1, this compound showed the following specific peaks.

δ (ppm) 0.9−1.0 (m, 9H, −CH ₃ ) 1.3−1.8 (m, 21H) 4.0−4.2 (m, 4H) 7.1−8.1 (m, 10H, aromatic) MS: M / e = 504 (P).

This compound was confirmed to have a smectic C phase in the range of 38 to 47 ° C.

 The phase transition temperature of this compound is shown below.

Cry is a crystalline phase, SmA is a smectic A phase, SmC is a chiral smectic C phase, Iso is an isotropic liquid, and the indicated temperature indicates a phase transition temperature in the arrow direction.

Example 2 Synthesis of 2- [2 '-{4 "-(R-2-methylbutylcarbonyl) phenyl} ethyl] -6-decyloxynaphthalene First Step 2-Carboxy-6-hydroxynaphthalene 3.76 g (2
0 mmol) and 3.12 g (10 mmol) of decyl tosylate in 0.66 g of 85% KOH, 40 ml of ethanol and 0.2 m of water
It was added to the mixed solution consisting of 1 and stirred at 90 ° C. for 15 hours.

Next, the reaction solution was poured into water and neutralized with hydrochloric acid.

After neutralization, the reaction product was extracted with ether, the extract was washed with water, and concentrated.

Using column chromatography from this concentrate 1.
6 g of 6-decyloxy-2-carboxynaphthalene was isolated.

2nd stage Lithium aluminum hydride 1.0 g (26.4 rimole) and 6-decyloxy-2-carboxynaphthalene 1.348 g (4.1 mmol) obtained in the 1st stage in anhydrous tetrahydrofuran (TMF) under argon atmosphere, room temperature for 2 hours. Then, the mixture was heated to reflux for 1 hour to react.

After allowing to cool, 150 ml of ether was added to dilute the reaction solution, and then saturated Na ₂ SO ₄ water was added to decompose excess lithium aluminum hydride to terminate the reaction.

The decomposed lithium aluminum hydride was separated, the solution was dried with anhydrous Na ₂ SO _4, and then the ether was removed.

The residue obtained by removing the ether was recrystallized from a mixed solvent of hexane / ethyl acetate (mixing volume ratio = 10: 1) to obtain 1.078 g of 6-decyloxy-2-hydroxymethylnaphthalene. Yield 85.8% Third stage 84 mg (0.43 mmol) of 6-decyloxy-2-hydroxymethylnaphthalene obtained in the second stage and 235 mg (2.57 mmol) of activated manganese dioxide were stirred in chloroform at room temperature for 12 hours. .

The reaction solution was separated, the solution was concentrated, and the obtained crude product was purified by silica gel thin layer chromatography to obtain 72.2 mg of white crystals of 2-carbanyl-6-decyloxynaphthalene.

Step 4 According to a conventional method, p-bromomethylbenzoic acid is reacted with methanol in the presence of an acidic catalyst to obtain methyl (4-bromomethylphenyl) carboxylate, and this methyl (4-bromomethylphenyl) carboxylate is obtained. The rate of 2.61 g (11.4 mmol) and triphenylphosphine of 3.0 g (11.4 mmol) were reacted by heating under reflux in benzene for 2 hours. After cooling, the formed crystals were collected.

By recrystallizing this crystal from benzene, (4
3.43 g of white crystals of (-methyloxycarbonyl) phenylmethylphosphonyl bromide were obtained.

Fifth stage 2-carbanyl-6-decyloxynaphthalene 475 mg
(2.47 mmol) and 1215 mg (25 mmol) of (4-methyloxycarbonyl) phenylmethylphosphonyl bromide obtained in the fourth step were dissolved in methylene chloride.

An aqueous solution of potassium hydroxide was gradually added to this solution, and after the reaction was completed, the reaction solution was concentrated.

The concentrate was purified by silica gel thin layer chromatography to give 2- [2'-4 "-(methyloxycarbonylphenyl) ethenyl] -6-decyloxynaphthalene 51 as a mixture of cis type and trans type.
9 mg (1.7 mmol) was obtained.

Sixth step 519 mg (1.7 mmol) of 2- [2'-4 "-(methyloxycarbonylphenyl) ethenyl] -6-decyloxynaphthalene obtained in the fifth step and a palladium-carbon catalyst (palladium content: 5% by weight) ) Was added to ethanol, and hydrogen gas was bubbled at room temperature for 5 hours.

Then, the reaction solution is passed through to concentrate the solution, and the solution is separated by column chromatography to give 2-
492 mg (1.1 mmol) of [2'-4 "-(methyloxycarbonylphenyl) ethyl] -6-decyloxynaphthalene was obtained.

Seventh step 2- [2'-4 "-(methyloxycarbonylphenyl) ethyl] -6-decyloxynaphthalene obtained in the sixth step (492 mg, 1.1 mmol) and R-2-methylbutanol (0.61 ml, 8.5 mmol) ) And t-butoxycalcium
0.1 ml and 40 ml of benzene were added, and the reaction solution was refluxed for 25 hours for reaction. After cooling, the reaction product was extracted with ether.

The extract was washed with an aqueous sodium hydrogen carbonate solution, further washed with water, and then concentrated.

The obtained concentrate was separated by column chromatography to obtain 485 mg of a white solid powder.

As a result of analysis, this crystal was found to be 2- [2 '-{4 "-(R
-2-methylbutylcarbonylphenyldiethyl]-
It was confirmed to be 6-decyloxynaphthalene.
Melting point: 48 ° C. ¹ H-NMR spectrum (270 MHz, CD
(Measured with Cl).

As is clear from FIG. 2, this compound showed the following specific peaks.

The δ (ppm) 0.7-1.0 (m, 9H, -CH 3) 1.1-1.8 (m, 21H) 3.3 (d, 2H) 3.7-4.1 (m, 4H) 6.9-7.9 (m, 10H, aromatic), The mass spectrum value was MS: M / e = 502 (P).

This compound was confirmed to have a smectic A phase in the range of 0 to 48 ° C.

 The phase transition temperature of this compound is shown below.

[Brief description of drawings]

Fig. 1 is a chart of the ¹ H-NMR spectrum of 2- [4 '(R-2 "-methylbutylcarbonyl) phenylmethyloxy] -6-decyloxynaphthalene. ¹ is a chart of ¹ H-NMR spectrum of {4 ″-(R-2-methylbutylcarbonylphenyl} ethyl] -6-decyloxynaphthalene.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toru Yamada 3 Chikusaigan, Ichihara City, Chiba Mitsui Oil Chemicals Co., Ltd. (56) References JP 62-10045 (JP, A) JP 63 -17847 (JP, A)

Claims (3)

[Claims] 1. A substituted naphthalene compound represented by the following formula [I]: (However, in the above formula [I], R ¹ has 1 to 18 carbon atoms.
R ² represents an alkyl group having 1 to 18 carbon atoms, and X represents either a group represented by —OCH ₂ — or a group represented by —CH ₂ CH ₂ —. , N is 0 or 1.). 2. A substituted naphthalene compound represented by the following formula [II], wherein R ² in the above formula [I] is an alkyl group having 2 or more carbon atoms; (However, in the above formula [II], R ¹ has 1 to 18 carbon atoms.
Represents an alkyl group, R ³ represents an alkyl group having 2 to 18 carbon atoms, X is -OCH ₂ - be any of the radicals represented by - group represented by, or -CH ₂ CH ₂ , N is 0 or 1, and ^* C represents an optically active carbon). 3. The substituted naphthalene compound according to claim 2, wherein in the formula [II], n is 1, R ³ is an ethyl group, and R ¹ is a decyl group.