Naphthalene compounds for liquid-crystalline mixtures

Abstract

The invention relates to compounds of the formula I, ##STR00001##
in which R, A, Z, m, L.sup.1, L.sup.2, L.sup.3 and X have the meanings indicated in Claim 1, to a process for the preparation thereof, and to liquid-crystalline media comprising at least one compound of the formula I and to electro-optical displays containing a liquid-crystalline medium of this type.

Claims

1. Compounds of the formula I, ##STR00017## in which X denotes Cl, R denotes a halogenated or unsubstituted alkyl radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in the halogenated or unsubstituted alkyl radical having 1 to 15 C atoms may each be replaced, independently of one another, by CC, CHCH, (CO)O, O(CO), (CO) or O in such a way that O atoms are not linked directly to one another, or a polymerisable radical, A denotes a) trans-1,4-cyclohexylene or cyclohexenylene, in which, in addition, one or more non-adjacent CH.sub.2 groups may be replaced by O and/or S and in which H may be substituted by F, b) 1,4-phenylene, in which one or two CH groups may be replaced by N and in which, in addition, one or more H atoms may be replaced by Br, Cl, F, CN, methyl, methoxy or a mono- or polyfluorinated methyl or methoxy group, Z denotes a single bond, CH.sub.2O, (CO)O, CF.sub.2O, CH.sub.2CH.sub.2CF.sub.2O, CF.sub.2CF.sub.2, CH.sub.2CF.sub.2, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, CHCH, CHCF, CFCF or CC wherein the asymmetrical definitions for Z may be oriented to any of both possible directions, L.sup.1, L.sup.2 and L.sup.3, independently of one another, denote H or F, and m denotes 0 or 1.

2. Compounds according to claim 1, characterised in that L.sup.3 denotes F.

3. Compounds according to claim 1, characterised in that R denotes alkyl, alkoxy, alkenyl or alkenyloxy having up to 8 carbon atoms or a polymerisable group.

4. Compounds according to claim 1, characterised in that L.sup.1 denotes fluorine and L.sup.2 denotes H.

5. Compounds according to claim 1, characterised in that L.sup.1 and L.sup.2 denote H.

6. Compounds according to claim 1 selected from the formulae: ##STR00018## in which R has the meanings indicated in claim 1.

7. Process for the preparation of compounds of the formula I according to claim 1, including a process step in which a boronic acid of the formula IIA or an open-chain or cyclic boronic acid ester of the formula IIB, ##STR00019## in which X, L.sup.1, L.sup.2 and L.sup.3 are defined as in claim 1, and R.sup.3, R.sup.4 denote alkyl having 1-12 C atoms or R.sup.3+R.sup.4 together also denote alkylene or 1,2-phenylene, where phenylene, R.sup.3, R.sup.4 and R.sup.3+R.sup.4 may also be substituted, is reacted with a compound of the formula III ##STR00020## in which Y denotes a group R-(A-Z).sub.m or OH, in which R, A, Z and m independently are defined as for formula I and Hal denotes O(SO.sub.2)CF.sub.3, Cl, Br or I, in the presence of a transition-metal catalyst.

8. The method comprising: preparing a liquid-crystalline medium comprising at least one compound of the formula I according to claim 1.

9. A liquid-crystalline medium comprising at least two mesogenic compounds, characterised in that it comprises at least one compound of the formula I according to claim 1.

10. A method comprising including the liquid-crystalline medium according to claim 9 in an electro-optical device.

11. Electro-optical liquid-crystal display containing a liquid-crystalline medium according to claim 9.

12. Compounds of the formula I, ##STR00021## in which X denotes F or Cl, R denotes a halogenated or unsubstituted alkyl radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in the halogenated or unsubstituted alkyl radical having 1 to 15 C atoms may each be replaced, independently of one another, by CC, CHCH, (CO)O, O(CO), (CO) or O in such a way that O atoms are not linked directly to one another, or a polymerisable radical, A denotes a) trans-1,4-cyclohexylene or cyclohexenylene, in which, in addition, one or more non-adjacent CH.sub.2 groups may be replaced by O and/or S and in which H may be substituted by F, b) 1,4-phenylene, in which one or two CH groups may be replaced by N and in which, in addition, one or more H atoms may be replaced by Br, Cl, F, CN, methyl, methoxy or a mono- or polyfluorinated methyl or methoxy group, Z denotes a single bond, CH.sub.2O, (CO)O, CF.sub.2O, CH.sub.2CH.sub.2CF.sub.2O, CF.sub.2CF.sub.2, CH.sub.2CF.sub.2, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, CHCH, CHCF, CFCF or CC, wherein the asymmetrical definitions for Z may be oriented to any of both possible directions, L.sup.1, L.sup.2 and L.sup.3, independently of one another, denote H or F, and m denotes 0 or 1, and wherein the compounds have liquid crystalline temperature range of at least 146 degrees C.

13. Compounds according to claim 12, wherein the compounds have an optical anisotropy n of at least 0.322.

Description

1.1 SYNTHESIS OF 2-HYDROXY-6-(2-FLUORO-4-CHLORO-1,1-BIPHENYL)NAPHTHALENE

(1) ##STR00009##

(2) 70 g (314 mmol) of 2-bromo-6-naphthol and 92.3 g (369 mmol) of 4-chloro-2-fluoro-1,1-biphenyl-4-boronic acid are initially introduced in a mixture of 600 ml of 1,4-dioxane and 300 ml of water, 65 g (613 mmol) of sodium carbonate and 6.7 g (9 mmol) of [1,1-bis(diphenylphosphino)-ferrocene]palladium(II) dichloride are added, and the mixture is refluxed for 16 h.

(3) The batch is cooled, MTB, water and 1 M aqueous hydrochloric acid are added, and the phases are separated. The aqueous phase is extracted twice with MTB, the combined organic phases are washed with saturated sodium chloride solution, dried over sodium sulfate, filtered and evaporated in a rotary evaporator. The residue is purified by column chromatography (SiO.sub.2, DCM) and subsequently washed by stirring with hot isopropanol, giving the product as a sand-coloured solid.

1.2 SYNTHESIS OF 2-TRIFLUOROMETHANESULFONYL-6-(2-FLUORO-4-CHLORO-1,1-BIPHENYL)NAPHTHALENE

(4) ##STR00010##

(5) 50 g (140 mmol) of the aromatic alcohol obtained in the preceding reaction are initially introduced in 450 ml of DCM and 27 ml (195 mmol) of triethylamine, 340 mg (2.8 mmol) of 4-(dimethylamino)pyridine are added, and 47 g (168 mmol) of trifluoromethanesulfonic anhydride are then added dropwise at 0 C. After 16 h, the mixture is worked up by addition of water. The phases are separated, and the organic phase is dried over sodium sulfate, filtered and evaporated in a rotary evaporator. The residue is purified by column chromatography (SiO.sub.2, heptane.fwdarw.heptane/DCM=1:1), giving the product as a yellow solid.

1.3 SYNTHESIS OF 2-BUTYL-6-(2-FLUORO-4-CHLORO-1,1-BIPHENYL)NAPHTHALENE

(6) ##STR00011##

(7) 13.9 g (60 mmol) of potassium phosphate are initially introduced in 100 ml of toluene, and 4.4 g (42 mmol) of butylboronic acid, 345 mg (0.6 mmol) of bis(dibenzylideneacetone)palladium(0) and 254 mg (0.6 mmol) of 2-dicyclohexylphosphino-2,6-dimethoxybiphenyl are added. 15 g (31 mmol) of the triflate obtained in the preceding reaction are added, and the mixture is refluxed for 18 h. The mixture is worked up by addition of MTB and water, the phases are separated, and the aqueous phase is extracted twice with MTB. The combined organic phases are washed with saturated sodium chloride solution, dried over sodium sulfate, filtered and evaporated in a rotary evaporator. The residue is purified by column chromatography (SiO.sub.2, heptane/toluene=9:1); the further purification is carried out by recrystallisation from isopropanol/toluene and from heptane/toluene mixtures. The desired product is obtained as a colourless crystalline solid.

(8) MS (EI): m/e (%)=388 (100, M.sup.+), 345 (94, [M-propyl].sup.+).

(9) C 113 SmA 200 N 248 I

(10) =11.8

(11) n=0.338

(12) .sub.1=1785 mPa.Math.s

(13) The following were synthesised in an analogous or comparable manner:

2. 2-BUTYL-6-(2-FLUORO-3-FLUORO-4-CHLORO-1,1-BIPHENYL)NAPHTHALENE

(14) ##STR00012##

(15) MS (EI): m/e (%)=406 (84, M.sup.+), 363 (100, [M-propyl].sup.+).

(16) Tg33 C 62 SmA 168 N 208 I

(17) =10.5

(18) n=0.322

(19) .sub.1=1392 mPa.Math.s

3. 2-PROPOXY-6-(2-FLUORO-3-FLUORO-4-CHLORO-1,1-BIPHENYL)NAPHTHALENE

(20) ##STR00013##

(21) MS (EI): m/e (%)=408 (56, M.sup.+), 366 (100, [M-C.sub.3H.sub.6].sup.+).

(22) C 112 SmA 193 N 246 I

(23) =+9.9

(24) n=0.35

(25) .sub.1=3156 mPa.Math.s

4. 2-BUTYL-6-(2-FLUORO-3,4-DIFLUORO-1,1-BIPHENYL)NAPHTHALENE

(26) ##STR00014##

(27) MS (EI): m/e (%)=390 (85, M.sup.+), 347 (100, [M-propyl].sup.+).

(28) C 69 SmA 148 N 179 I

(29) =10.3

(30) n=0.291

(31) .sub.1=836 mPa.Math.s

5. 2-METHOXY-6-(2,3,4-TRIFLUORO-1,1-BIPHENYL)NAPHTHALENE

(32) ##STR00015##

(33) MS (EI): m/e (%)=364 (100, M.sup.+), 321 (44, [M-C.sub.3H.sub.6].sup.+).

(34) C 134 N 235 I

6. SYNTHESIS OF 2-(METHACRYLOYL)OXO-6-(2-FLUORO-4-CHLORO-1,1-BIPHENYL)-NAPHTHALENE

(35) ##STR00016##

(36) 9.5 g (27 mmol) of 2-hydroxy-6-(2-fluoro-4-chloro-1,1-biphenyl)naphthalene, 3.3 g (38 mmol) of methacrylic acid and 33 mg (2.7 mmol) of 4-(dimethylamino)pyridine are initially introduced in 100 ml of dichloromethane, the mixture is cooled to 0 C., and 6.1 g (39 mmol) of 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide in 20 ml of dichloromethane are then added. The mixture is stirred for 18 h, warmed to room temperature in the process and subsequently worked up by direct filtration (SiO.sub.2, heptane/dichloromethane=1:1). The further purification is carried out by recrystallisation from acetonitrile/toluene and from ethyl acetate/tetrahydrofuran mixtures. The desired product is obtained as a colourless crystalline solid.

(37) MS (EI): m/e (%)=416 (52, M.sup.+), 69 (100, [CH.sub.3C(CH.sub.2)CO].sup.+).

(38) C 144 SmA 203 N decomp.

(39) Further combinations of the embodiments and variants of the invention in accordance with the description also arise from the following claims.