JPS59193843A - Fluoroacetophenone derivative - Google Patents

Abstract

NEW MATERIAL:4-( trans-4-Substituted-cyclohexyl )-2-fluoroacetophenone of formula I (R is 1-10C alkyl or alkoxy). EXAMPLE:4-(trans-4-Heptylcyclohexyl)-2-fluoroacetophenone. USE:A low-viscosity liquid crystal substance which is added to other liquid crystal compositions to improve the driving voltage and the viscosity in low temperature zones. PREPARATION:The reaction of 3-fluorobromobenzene of formula II with Mg in tetrahydrofuran give the compound of formula III, which is allowed to react with a 4-substituted cyclohexanone to give a compound of formula IV. The product is subjected to dehydration in the presence of KHSO4 to give a compound of formula V, then the product is subjected to catalytic reduction in the presence of Raney nickel to give a compound of formula VI. Finally the compound is allowed to react with acetyl chloride in carbon disulfide in the presence of aluminum trichloride to give the compound of formula I .

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel liquid crystalline material of low viscosity and to a composition containing the material.

Liquid crystal display teeth (TN) utilize the optical anisotropy and dielectric anisotropy of liquid crystal materials, and depending on the display format,
It is divided into various types such as type (twisted nematic type), DS type (dynamic scattering type), guest-host type, and DAP type.
The properties of liquid crystal materials suitable for each use vary. It is common for all liquid crystal materials to be stable against moisture, air, heat, light, etc., and they are also required to exhibit a liquid crystal phase over as wide a temperature range as possible, centered around room temperature. ing. At present, there is no single compound that satisfies these conditions, and liquid crystal compositions that can be used by mixing several types of liquid crystal compounds and non-liquid crystal compounds have been put into practical use.

The compounds of the present invention are those whose viscosity can be expressed mathematically, especially at low temperatures.

That is, the compounds f and j of the present invention have the general formula (in the above formula, 1't is an alkyl group having 1 to 10 carbon atoms or an alkoxy group) and is a 4-(trans-4-substituted compound). cyclohexyl)-2-fluoroacetophenone (tj
, non-liquid crystal material 1. ! J and viscosity r;, Ftl' 3] lower than L 20 cp (11'I can also be obtained,
By adding it to other liquid crystal compositions, it is possible to improve the driving 'dL pressure, the viscosity H in the low crystal region, )), -:5-.

0((〆ζ本')6'The method for producing 1'A',! of the compound Jj will be described.

3-Fluorobromobenzene (11) was reacted with red sea bream sium in tetrahydrofuran to give 3-fluorobenzene magnesium bromide (III), which was then treated with 4
-Substituted cyclohexanone is added to give 3-(4-substituted cyclohexan-1-ol)fluorobenzene (IV). This was dehydrated using potassium hydrogen sulfate as a catalyst and 1,8-
(41!-substituted cyclohexen-1-yl)fluorobenzene (V) is obtained. This product was subjected to catalytic reduction with Raney nickel in toluene to produce 3-(4-substituted cyclohexyl).
Fluorobenzene (Company) is obtained. This (vD) was reacted with acetyl chloride in carbon disulfide in the presence of aluminum chloride, and the desired 4-(trans-4,-8m
cyclohexyl)-2-fluoroacetophenone (1)
'e Manufacture.

The above is expressed as a chemical formula as follows.

(II) Tsukuda) (1) The present invention will be explained in more detail with reference to Examples below.

-Jinjiriki i! i 1cri 1 4-(trans-4-hebutylcyclohexyl)-2-
Preparation of fluoroacetophenone Dissolve 8-fluorobromobenzene ([1) 26.6y (0,152 mol) in 100-year old tetrahydrofuran 1.1. '',! A reaction was carried out with Magui sium piece 37Q (0,152 gram atom) at 40°C for 2 hours in an air flow. When red sea bream pieces disappear, cool it, add 21.6y (0.11 mol) of 4-hebutylcyclohexanone in 100+rrl of tetrahydro7ran at full speed, and add warm 1f to 3(1'C). After dropping, the temperature was maintained at reflux for 2 hours, and 3N-
100+v7 of edible acid was added, and the oily layer was extracted with 250 g of n-hebutane and washed with water until the water became neutral. Oil) was distilled off under reduced pressure to give 3-(4-hegetylcyclohexyl-1)
-ol) An oily residue of fluorobenzene (IV) was obtained. To this was added 7 g of potassium hydrogen sulfate, and the mixture was dehydrated at 180°C for 2 hours under a nitrogen atmosphere. After cooling, potassium hydrogen sulfate was added separately, and 200 mJ' of n-hebutane was added (separated into layers.Then, the washing solution was washed with water until it became neutral, and the n-hebutane) was added. Add 3 g of anhydrous sodium sulfate to J and leave it overnight, then distill under reduced pressure to obtain the main fraction (V) (boiling point 22
0℃/4 miHg)? : Collection meta. Kono Mono 2O
f was dissolved in toluene 100++y/, 2N nickel 71 was added, and catalytic reduction was carried out at room temperature and pressure for 10 hours. After all the catalyst was separated, toluene was distilled off under reduced pressure, and the remaining oil was distilled off under reduced pressure. Dissolve 7.2y of aluminum chloride in 50πt of main distillate, add 5.3y of acetyl chloride over 10 minutes at 2-5°C with stirring, and gradually raise the temperature to 35.
It was kept at °C for 2 hours. Then, after cooling, 6N-hydrochloric acid 50πI
Add YK and extract the oil layer with 100g/toluene L7″-8
Next, after washing with water and the washing liquid became neutral, the solvent was distilled off under reduced pressure and recrystallized using ethanol.
4-hectylcyclohexyl)-2-fluoroacetophenone (1) was proposed. Yield fr, j: 9 Q TelJ
t point &j35.6~40.2"<2,-'?" bright point/:j, 21.5°C'j3: shown.

夷〃(11 cases 2-5 Ten h1!1 was manufactured using a method similar to Example 1 (compound cutting).

The results are shown in Table 1 together with Example 1.

As the phase 1 phase transition point, the melting point chem, p, , I Machinku ψ] point is approximately elevated to N-].

Implementation 6 (Usage example) Current range of I-matic temperature of several existing compositions ([], -1
0 to 72.1"C, viscosity at 20°C is 28cp, transparent electrode, inner wall distance IQ) t7
7Z's TN cell has an old Schiff/threshold value in this case 'NUN
pressure, 1.76Vηpack M'll pressure C1, 2, 40V
Met.

4-( according to Example 1 of 71 papers in the 1-nuclear liquid crystal composition 95 parts)
The N-I point of this liquid crystal composition was 68.4° (20°C), but the N-I point of this liquid crystal composition was 68.4° ().
When the viscosity was 27 cp, the threshold voltage was 1.69V, and the saturation voltage was 2.32V.

that's all Patent applicant: Chisso Corporation r41-・I Fuchiyu 1-゛

Claims (1)

[Scope of Claims] (4-(trans-4-substituted cyclohegycyl)-2-fluoro A fluoroacetophenone derivative which is acetophenone. A liquid crystal composition containing at least one fluoroacetophenone derivative which is xyl-2-fluoroacetophenone.