JPS6241591B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a nematic liquid crystal 5-cyan-2-[4 -Substituted-phenyl]-Relating to pyrimidines. Nematic liquid crystal materials with positive dielectric anisotropy are used in electro-optical devices based on field effects, especially the Schadt-Helfrich effect [G. Meier, E.
Applications of Liquid by Sackmann and JG Grabmaier
Crystals, Springer Publishing, Berlin, Heidenberg, New York (1975)]. The materials used hitherto, which always consist of mixtures of a wide variety of compounds, have threshold values and operating voltages that are too high on the one hand and clearing points that are on the other hand too low, so that they cannot be used at high temperatures. not suitable for The object of the invention is a nematic liquid crystal with a high positive dielectric anisotropy, a low threshold and operating voltage and a high clearing point, and a method for its production. This object is solved by producing new nematic liquid crystal materials and by a hitherto unknown method for producing them. The inventor has determined that the general formula [In the formula, R ¹ is

【formula】

[Formula] means C _o H _2o+1 OCOO-, C _o H _2o+1 O- or C _o H _2o+1 -, provided that R ² is C _o H _2o+1 - or C _o H _2o+1 means O- and
R ³ is C _o H _2o+1 , where n is from 1 to 10. ] 5-cyan-2- of the nematic liquid crystal represented by
We have discovered [4-substituted-phenyl]-pyrimidines. The production of 5-cyan-2-[4-substituted-phenyl]-pyrimidines of the present invention involves the production of 5-cyan-2-[4-substituted-phenyl]-pyrimidines.
[4-alkyl or alkoxy-phenyl]
-For pyrimidines, reaction formula [In the formula, R means an alkyl or alkoxy group. ], and in the case of 5-cyan-2-[4-acyloxy-phenyl]-pyrimidines, the reaction product in which R is an OH group in the reaction formula is converted to Einhoren according to the reaction formula. or by reaction with acid chlorides according to a modification of Schtten-Baumann: 5-Cyan-2-[4-substituted-phenyl]-pyrimidine of the liquid crystal of the invention for use in electro-optical construction elements for modulating transmitted or reflected light and for depicting numbers, symbols and figures in black and white or in color are used according to the invention in a composition containing at least one liquid crystal compound. The advantages of the compounds according to the invention are their high dielectric anisotropy, high clearing point and low threshold and operating voltage. One advantage lies in the ability to represent numbers, symbols or figures in black and white - or in color - in electro-optical devices. The present invention will be explained in more detail with reference to the following five examples. Example 1 Table 1 below provides specific examples of 5-cyan-2-[4-acyloxy-phenyl]-pyrimidines (final products prepared according to Example 3).

[Table] Example 2 30% 4-n-propylcyclohexane-carboxylic acid-4-cyan-phenyl ester, 30% 4-n-butylcyclohexane-carboxylic acid-4
-cyanphenyl ester, 30% of 4-n-pentylcyclohexanecarboxylic acid-4-cyanphenyl ester and 10% of 5-cyan-2-[4
-Hexyloxycarbonyloxy-phenyl]
-Pyrimidine compositions are suitable for elements of electro-optical structures based on the Schierdet-Helfrich effect and have the following properties: Melting point: 0-10° C. Clear Point: 73℃ Threshold voltage: 1.3V, 50Hz Operating voltage: 2.6V Example 3 a Method for manufacturing 5-cyan-2-[4-hydroxy-phenyl]-pyrimidine: 50ml anhydrous trimethylamine, 50ml anhydrous pyrimidine, 17.3g (0.1 mol) of 4-hydroxybenzamidine-hydrochloride and 11 g
(0.1 mol) of α-cyan-β-dimethylamino-
Acrolein is heated to 80° C. for 6 hours while stirring. The dark brown colored reaction mixture was poured onto ice/concentrated sulfuric acid (500 g/50 ml) and the precipitate was filtered off with suction.
Wash thoroughly with water and recrystallize with methanol/activated carbon. The yield is 12.8g (theoretical value 65
%). F: 160-262 (sublimated). b Production of 5-cyan-2-[4-acyloxy-phenyl]-pyrimidines: 1.97 g (0.01 mol) of 5-cyan-2-[4-
Hydroxy-phenyl]-pyrimidine and 2.01
25 g (0.015 mol) of hexanoyl chloride
ml of anhydrous pyridine at room temperature for 6 hours, then heated under reflux for 5 minutes and left overnight. The reaction product was mixed with ice/concentrated sulfuric acid (300g/20
ml), take up in ether and wash the ether layer with 1N KOH solution and water. Then with Na
It is dried with SO ₄ , the solvent is distilled off on a rotary evaporator, and the residue is recrystallized several times from N-hexane. Yield is 70-90% of theory. Table 1 shows the physical properties of the obtained 5-cyan-2-[4-hexanoyl-phenyl]-pyrimidine. Other products listed in Table 1 below were also produced in the same manner as above. However, instead of hexanoyl chloride, R ² groups in Table 1-
It was carried out using acid chloride with COCl.

[Table] Example 4 Preparation of 5-cyan-2-[4-alkyl- or alkoxy-phenyl]-pyrimidines: 40 ml anhydrous triethylamine, 1.1 g (0.01 mol) α-cyan-β-dimethyl-aminoacrolein and 2.244 g (0.01 mol) of 4-butoxy-benzamidine-hydrochloride or its free base are heated to 80° C. for 6 hours with stirring.
The cooled reaction mixture is poured onto 150 g of ice/30 ml of concentrated sulfuric acid, the precipitate is filtered off with suction, washed thoroughly with water and finally recrystallized several times in n-hexane. Yield is 75-95% of theory. Table 2 shows the physical properties of the product, 5-cyan-2-[4-butoxy-phenyl]-pyrimidine. The other products listed in Table 2 were also produced in the same manner as above. However, instead of 4-butoxy-benzamidine-hydrochloride, a compound shown in Table 2 with an -amidine-hydrochloride group attached to the R group was used.

【table】

Claims (1)

[Claims] 1. General formula [In the formula, R ¹ means [Formula] [Formula] C _o H _2o+1 OCOO-, C _o H _2o+1 O-, or C _o H _2o+1 -, provided that R ² is C _o H _{2o +1} -- or C _o H _2o+1 O -- and
R ³ is C _o H _2o+1 , where n is from 1 to 10. ] 5-cyan-2- of the nematic liquid crystal represented by
[4-Substituted-phenyl]-pyrimidines. 2 General formula [In the formula, R ¹ means [Formula] [Formula] C _o H _2o+1 OCOO-, C _o H _2o+1 O-, or C _o H _2o+1 -, provided that R ² is C _o H _{2o +1} -- or C _o H _2o+1 O -- and
R ³ is C _o H _2o+1 , where n is from 1 to 10. ] 5-cyan-2- of the nematic liquid crystal represented by
[4-Substituted-phenyl]-pyrimidine for modulating transmitted or reflected light, and for displaying numbers, symbols and figures in black and white or in color, characterized by using a mixture containing at least one type of pyrimidine. Nematic liquid crystal compositions for electro-optical structural elements.