JPH0316958B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is based on the general formula [] (In the formula, R ¹ is an alkyl group or an alkoxy group,
R ² is an alkyl group, an alkoxy group, a halogen atom,
2-(4′-substituted phenyl)-5-(4″-substituted phenyl)-1,3,2- represented by cyan group, nitro group, dimethylamino group, alkoxycarbonyl group, and hydroxycarbonyl group, respectively) This invention relates to a dioxaborinane compound, its production method, and a liquid crystal composition containing the same.In the general formula [], the boron-containing skeleton is named as follows. In the general formula [], ^R1 represents an alkyl group or an alkoxy group having 1 to 10 carbon atoms, preferably a straight chain alkyl group or a straight chain alkoxy group having 1 to 8 carbon atoms. Also
R ² is an alkyl group, an alkoxy group, a halogen atom,
Indicates cyan group, nitro group, dimethylamino group, alkoxycarbonyl group, and hydroxycarbonyl group. The compounds of the present invention have large dielectric anisotropy, excellent compatibility, and a wide nematic or smectic mesophase, so they can be used as liquid crystal materials. The liquid crystal phase forms an intermediate phase between a crystalline solid and a randomly arranged liquid phase, and within the liquid crystal phase, molecules are arranged in a regular order over a wide range. There are roughly two types of liquid crystal phases. That is, the extensive regular array is essentially a thin layer. type of smectic mesophase, and nematic mesophase in which the arrangement of the molecules is substantially linear, that is, the molecules are arranged parallel to the longitudinal direction of the molecules. Cholesteric mesophases may also be classified as a subclass of nematic mesophases or as separate mesophases. In addition to the linear arrangement of the nematic mesophase, the cholesteric mesophase has a regular arrangement of small spiral regions. It is generally said that liquid crystal properties are due to long molecules. To date, a huge number of liquid crystal compounds have been synthesized and studied, and some of them have been put into practical use, but most of them are pure organic compounds. In addition, liquid crystal materials made of organometallic compounds and organometallic complex compounds have been proposed in hopes of providing electrical and physical properties that cannot be achieved with pure organic compounds, but their synthesis methods are difficult and their chemical stability is limited. However, since many basic problems remain, such as solubility, the number of them is extremely small and they have not been put into practical use. The compound of the present invention has a structure that matches the molecular characteristics of the liquid crystal described above, and although it is an organometallic compound, it has a high clearing point, particularly excellent stability, high compatibility, and exhibits the liquid crystal properties described above. When the compound of the present invention was left in the air in the laboratory for one year, it showed no change in its color, melting point, optical properties, etc. If necessary, the liquid crystal compound of the present invention may include conventionally known pure organic compound liquid crystal substances, such as Schiff's base type, azoxy type, benzoic acid phenyl ester type,
Cyclohexanecarboxylic acid phenyl ester,
Compounds such as cyclohexanecarboxylic acid cyclohexane ester, biphenyl, phenylcyclohexane, phenylpyrimidine, and phenylmetadioxane may be mixed in any proportion. An outline of the method for producing the compound of the present invention is shown by the following formula. (In the above formula, X ¹ is an iodine atom or a bromine atom,
X ² represents a halogen atom, R represents an alkyl group, and R ¹ and R ² have the same meanings as above). That is, first, ethyl cyanacetate was added to potassium t in ethylene glycol dimethyl ether solvent.
- Reaction with 4-substituted phenyl bromides or borides in the presence of butoxide and palladium compound catalysts to give ethyl α-cyano-4-substituted phenyl acetates, which was dissolved in 95% ethanol in the presence of acidic catalysts. Esterification is performed to obtain ethyl 2-(4'-substituted phenyl)malonate. This ester compound is then reduced using lithium aluminum hydride in an ether or tetrahydrofuran solvent to reduce the 2-
(4'-substituted phenyl)-1,3-propanediol []. Meanwhile, 4-chloride or bromide in tetrahydrofuran
A Grignard reagent synthesized from substituted phenyl and magnesium metal is reacted with trimethyl borate to obtain 4-substituted phenylboronic acid. 4-Carboxyphenylboronic acid [] is obtained by oxidizing tolylboronic acid with potassium permanganate. 2-(4′-substituted phenyl)-1 obtained above,
3-Propanediol [] and 4-substituted phenylboronic acid [] or [] are subjected to a dehydration reaction in an inert organic solvent capable of azeotropic dehydration to obtain the compound 2-(4'-substituted phenyl)-5- of the present invention. (4″-substituted phenyl)-1,3,2-dioxaborinane compound []
Or obtain [a]. Although this reaction can be carried out in the absence of a solvent, it is usually carried out in the presence of a solvent such as benzene, toluene, n-hexane, cyclohexane, or n-heptane. 2-(4′-alkoxycarbonylphenyl)-5-(4″-substituted phenyl)-1,3,2- of the present invention
Dioxaborinane compound [b] is 2-(4'-
carboxyphenyl)-5-(4″-substituted phenyl)
2-(4′-cyanophenyl)-5-(4″-substituted phenyl) obtained by esterifying -1,3,2-dioxaborinane [Ia] in alcohol in the presence of an acidic catalyst; -1,3,2-
Dioxaborinane [c] is 2-(4′-carboxyphenyl)-5-(4″-substituted phenyl)-1,
3,2-dioxaborinane [a] is converted to the corresponding acid chloride [V] by using a chlorinating agent such as thionyl chloride, phosphorus trichloride, or phosphorus pentachloride, and then converted to the corresponding acid amide compound [] by the action of ammonia. It can be obtained by deriving and treating it with a dehydrating agent such as a tetrahydrofuran solution of phosphorus oxychloride, thionyl chloride, phosphorus pentoxide, triphenylphosphine and carbon tetrachloride. The present invention will be explained below by way of examples.
% in the examples indicates weight %. Production Example 1 Synthesis of 2-(4'-substituted phenyl)-1,3-propanediol Into a three-neck flask equipped with a stirrer, thermometer, dropping funnel, and reflux condenser, 15 g (0.4 mol) of lithium aluminum hydride was added. ) and 600ml of anhydrous ether
The 2-(4'-substituted phenyl) listed in Table 1 below was added to the suspension with vigorous stirring.
A solution of 0.2 mol of ethyl malonate dissolved in 20 ml of anhydrous ether was added dropwise at an internal temperature of 5°C. After the dropwise addition was completed, the reaction was carried out at reflux temperature for 6 hours. After the reaction is complete,
The reaction product was ice-cooled and ether saturated with water was added to decompose the excess lithium aluminum hydride.
Next, 10 ml of a 5% aqueous sodium hydroxide solution was added dropwise to 50 ml, and the mixture was stirred at 25°C overnight. After removing the white inorganic substance produced and concentrating the mother liquor, the residue was recrystallized from n-hexane or benzene to give 2 in Table 1 below.
-(4'-substituted phenyl)-1,3-propanediol [ ] was obtained.

[Table] Production Example 2 Synthesis of 4-substituted phenylboronic acid In a 500 c.c. three-necked flask equipped with a stirrer, thermometer, dropping funnel and nitrogen gas inlet tube, 19 g (0.19 mol) of trimethyl borate and anhydrous were added under a nitrogen stream. Add 100ml of tetrahydrofuran and stir to make a solution.
The internal temperature was maintained at -60° C. or lower in a dry ice tank, and 120 ml of an anhydrous tetrahydrofuran solution containing 0.18 mol of 4-substituted phenylmagnesium bromide was added dropwise to this solution over about 10 minutes with stirring. After stirring at -60°C for 2 hours, 13 ml of water was added dropwise, and using the heat of reaction, the internal temperature was gradually raised to -30°C. Next, remove the dry ice tank and use concentrated sulfuric acid.
While dropping 100 ml of an aqueous solution containing 5.6 ml, the temperature was raised to room temperature to complete the reaction. Tetrahydrofuran was distilled off under reduced pressure, and 300 ml of ether was added to extract the target product. After distilling off the ether, the white solid was washed with n-hexane to remove impurities.
After recrystallization from pure water and air drying, the 4-substituted phenylboronic acids shown in Table 2 below were obtained.

[Table] Production Example 3 Synthesis of 4-carboxyphenylboronic acid Into two three-necked flasks equipped with a stirrer, thermometer, and dropping funnel, 16.3 g (0.12
mol) and an aqueous solution containing 10 g of sodium hydroxide 150
ml, stirred to dissolve well, and then diluted with 600 ml of water. Add potassium permanganate to this aqueous solution.
A saturated aqueous solution containing 40 g (0.25 mol) was added dropwise at 25° C. over 6 hours. After the addition was completed, stir overnight.
The precipitated brown solid was removed to obtain a colorless and transparent mother liquor. This mother liquor was concentrated to a total volume of about 200 ml, acidified with concentrated hydrochloric acid, and the precipitated target product was collected. After washing with water, recrystallizing from water, and air drying, melting point 295
Paracarboxyphenylboronic acid with a temperature of ~318°C (decomposed) was obtained. The yield was 80%. Example 1 2-(4′-substituted phenyl)-5-(4″-
Production of substituted phenyl)-1,3,2-dioxaborinane [] and [a] Production Example 1 was placed in a 200 c.c. four-necked flask equipped with a stirrer, a thermometer, and an azeotropic dehydrator with a reflux condenser. 0.01 mol of 2-(4'-substituted phenyl)-1,3-propanediol obtained in Example 2 and 0.01 mol of 4-substituted phenylboronic acid obtained in Production Example 2 were charged together with 50 ml of toluene, and azeotropic dehydration was carried out at reflux temperature. Ta. The reaction was completed in about 1 to 2 hours, and the 2-(4′-substituted phenyl)-5-(4″-substituted phenyl)-1,3,2-
Dioxaborinan was obtained with a yield of 88-96%. A compound with even higher purity can be obtained by recrystallization from petroleum ether. The results are shown in Table 3 along with the physical properties of these compounds. The symbols in the table below represent the following: C: crystal, S: smectic, N: nematic, I: isotropic liquid ( ): not observed during heating cycles,
Monotropic transition temperature observed during cooling C-I: Indicates a phase change from crystal to isotropic liquid C-N (or S): Indicates a phase change from crystal to nematic or smectic S-N (or I) : Indicates a phase change from smectic to nematic or isotropic liquid N-I (or S-I): Indicates a phase change from nematic or smectic to isotropic liquid

[Table] Example 2 2-(4′-alkoxycarbonylphenyl)-5-(4″-substituted phenyl)-1,3,2
-Production of dioxaborinane [Ib] 100 c.c. equipped with stirrer, thermometer and reflux condenser.
2-(4′-carboxyphenyl)-5-(4″-substituted phenyl)- obtained in Example 1 was placed in a three-necked flask.
1,3,2-dioxaborinane (5 mmol)
and 20g of alcohol and a catalytic amount of concentrated sulfuric acid,
The reaction was allowed to proceed for 12 hours at reflux temperature with stirring. After the reaction, the alcohol was distilled off under reduced pressure, and the residue was isolated and purified by silica gel chromatography (20 g of 200 mesh silica gel, developing solvent dichloromethane) to obtain 2-(4'-alkoxycarbonylphenyl)-5. -(4″-substituted phenyl)-1,3,2
-Dioxaborinane compounds were obtained with a yield of 70-89%. A compound with even higher purity can be obtained by recrystallization from petroleum ether. The results are shown in Table 4 along with the physical properties of the obtained compound.

[Table] Example 3 2-(4'-cyanophenyl)-5-
Production of (4″-substituted phenyl)-1,3,2-dioxaborinane [Ic] 100 c.c. equipped with stirrer, thermometer and reflux condenser.
2-(4′-carboxyphenyl)-5-(4″-substituted phenyl)- obtained in Example 1 was placed in a three-necked flask.
1,3,2-dioxaborinane (5 mmol) and 2.0 g of thionyl chloride were charged and dissolved under stirring.
After reacting in an oil bath at 70°C for 2 hours, excess thionyl chloride was distilled off under reduced pressure to obtain the corresponding acid chloride. Meanwhile, in a reaction vessel similar to the above,
% aqueous ammonia and 20 ml of ether were charged, and the acid chloride synthesized above was added thereto at room temperature, followed by stirring for 2 hours. After the reaction was completed, ether, water and ammonia were distilled off under reduced pressure to obtain the corresponding acid amide []. Next, this acid amide [] was transferred to the same reaction vessel as above, and tetrahydrofuran was added.
40 ml of carbon tetrachloride, 40 ml of carbon tetrachloride, and 3.0 g of triphenylphosphine were charged, dissolved under stirring, and reacted for 1 hour on an oil bath at 70°C. After the reaction, tetrahydrofuran and carbon tetrachloride were distilled off under reduced pressure.
The residue was isolated and purified by silica gel column chromatography (30 g of 200 mesh silica gel, developing solvent benzene-methylene chloride), and 2-
(4′-cyanophenyl)-5-(4″-substituted phenyl)
-1,3,2-dioxaborinane compound 71-75
% yield. A compound with even higher purity can be obtained by recrystallization from petroleum ether. The results are shown in Table 5 along with the properties of the obtained compounds.

[Table] Example 4 As shown in Table 6, when a mixture of two or more dioxaborinane compounds of the present invention or a mixture of the compound of the present invention and another liquid crystal substance was mixed in a eutectic state, low melting point and Liquid crystal compositions with a wide range of nematic properties were obtained. The results along with their physical and electrical properties are shown in Tables 6 and 7.

【table】

【table】

[Table] From the above results, the mixture of the compound of the present invention and the mixture of the compound of the present invention and other liquid crystal substances exhibit a colorless and stable nematic liquid crystal phase, and can be used as liquid crystal substances in various electro-optical display devices. Has suitable thermal properties.

Claims (1)

[Claims] 1. General formula (In the formula, R ¹ is a straight-chain alkyl group or a straight-chain alkoxy group having 1 to 10 carbon atoms, and R ² is 1 to 10 carbon atoms.
Straight chain alkyl group or straight chain alkoxy group having 10 carbon atoms, halogen atom, cyan group, 2
2-(4′-substituted phenyl)-5-, which represents a straight-chain alkoxycarbonyl group or hydroxycarbonyl group having ~6 carbon atoms, respectively)
(4″-substituted phenyl)-1,3,2-dioxaborinane compound. 2 The alkyl group or alkoxy group of R ¹ and R ² is a linear alkyl group or a linear alkoxy group having 1 to 8 carbon atoms. The compound according to claim 1, characterized in that it has the following general formula: 2-(4'-substituted phenyl)-1, represented by (in the formula, R ¹ represents an alkyl group or an alkoxy group),
General formula characterized by dehydrating 3-propanediol and 4-substituted phenylboronic acid (In the formula, R ¹ is an alkyl group or an alkoxy group,
R ² is an alkyl group, an alkoxy group, a halogen atom,
2 represented by cyan group, alkoxycarbonyl group or hydroxycarbonyl group, respectively)
-(4′-substituted phenyl)-5-(4″-substituted phenyl)
- A method for producing a 1,3,2-dioxaborinane compound. 4 General formula 2-(4'-carboxyphenyl) represented by (in the formula, R ¹ represents an alkyl group or an alkoxy group)
A general formula characterized by reacting a -5-(4″-substituted phenyl)-1,3,2-dioxaborinane compound with a lower alcohol in the presence of an acidic catalyst. (In the formula, R ¹ is an alkyl group or an alkoxy group,
R ³ represents a lower alkyl group)
(4'-alkoxycarbonylphenyl)-5-
Method for producing (4″-substituted phenyl)-1,3,2-dioxaborinane compound. 5 General formula 2-(4'-carboxyphenyl) represented by (in the formula, R ¹ represents an alkyl group or an alkoxy group)
-5-(4″-substituted phenyl)-1,3,2-dioxaborinane compound is treated with a chlorinating agent to form the corresponding acid chloride, and then ammonia is applied to induce the corresponding acid amide compound. , a general formula characterized in that it is converted into a cyanide compound by a dehydrating agent. 2-(4'-cyanophenyl)-5 represented by (in the formula, R ¹ represents an alkyl group or an alkoxy group)
-(4″-substituted phenyl)-1,3,2-dioxaborinane compound manufacturing method. 6 General formula (In the formula, R ¹ is a straight-chain alkyl group or a straight-chain alkoxy group having 1 to 10 carbon atoms, and R ² is 1 to 10 carbon atoms.
Straight chain alkyl group or straight chain alkoxy group having 10 carbon atoms, halogen atom, cyan group, 2
2-(4'-substituted phenyl)-1, represented by a linear alkoxycarbonyl group or a hydroxycarbonyl group having ~6 carbon atoms, respectively
At least one 3,2-dioxaborinane compound
A liquid crystal composition characterized by containing seeds.