AROMATIC ISOTHIOCYANATES

Abstract

The present invention relates to a compound of formula G

##STR00001##

as defined in claim 1, to a liquid crystal medium comprising a compound of formula G and to high-frequency components comprising these media, especially microwave components for high-frequency devices, such as devices for shifting the phase of microwaves, tunable filters, tunable metamaterial structures, and electronic beam steering antennas, e.g. phased array antennas.

Claims

1. A compound of formula G ##STR00400## in which R.sup.G denotes H, fluorinated or non-fluorinated straight chain or branched alkyl having 1 to 12 C atoms, or fluorinated or non-fluorinated straight chain or branched alkenyl having 2 to 12 C atoms, in which one or more CH.sub.2-groups may be replaced by ##STR00401## and in which one or more non-adjacent CH.sub.2-groups may be replaced by O, Z.sup.G1 and Z.sup.G2, identically or differently, denoteCH?CH, CF?CF, CH?CF, CF?CH, C?C, C?CC?C or a single bond, X denotes Cl or F, R denotes linear or branched or cyclic alkyl having 1 to 6 C atoms, t is 0, 1 or 2, and ##STR00402## identically or differently, denote a radical selected from the following groups: a) the group consisting of 1,4-phenylene, 1,4-naphthylene, and 2,6-naphthylene, in which one or two CH groups may be replaced by N and in which one or more H atoms may be replaced by L, b) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene, tetralin-2,6-diyl, tetralin-5,8-diyl, decalin-2,6-diyl, bicyclo[1.1.1]pentane-1,3-diyl, 4,4-bicyclohexylene, bicyclo[2.2.2]octane-1,4-diyl, and spiro[3.3]heptane-2,6-diyl, in which one or two CH groups may be replaced by N, one or more non-adjacent CH.sub.2 groups may be replaced by O and/or S and in which one or more H atoms may be replaced by L, c) the group consisting of thiophene-2,5-diyl, thieno[3,2-b]thiophene-2,5-diyl, selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by L, L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF.sub.5 or straight-chain or branched, in each case optionally fluorinated, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy each having 1 to 12 C atoms.

2. The compound according to claim 1, wherein R denotes methyl.

3. The compound according to claim 1, wherein X denotes fluorine.

4. The compound according to one or more of claim 1, wherein the compound is selected from the compounds of the formulae G-1 to G-6 ##STR00403## in which R.sup.G, Z.sup.G1, Z.sup.G2, ##STR00404## have the meanings given in claim 1.

5. The compound according to one or more of claim 1, wherein Z.sup.G1 and Z.sup.G2 denoteCF?CF or C?C.

6. The compound according to one or more of claim 1, wherein ##STR00405## denote ##STR00406## ##STR00407## in which R.sup.L, on each occurrence, identically or differently, denotes H or alkyl having 1 to 6 C atoms, or denote ##STR00408## which one or more H atoms may be replaced by a group R.sup.L or F, wherein R.sup.L denotes H or alkyl having 1 to 6 C atoms.

7. A liquid crystal medium comprising one or more compounds of formula G according to one or more of claim 1.

8. A component for high-frequency technology, characterized in that it comprises the liquid crystal medium according to claim 7.

9. The component according to claim 8, wherein the component is a liquid-crystal based antenna element, a phase shifter, a tunable filter, a tunable metamaterial structure, a matching network or a varactor.

10. A microwave antenna array, characterized in that it comprises one or more components according to claim 8.

11. A method for the production of a compound of formula G according to one or more of claim 1, characterized in that a compound of formula N ##STR00409## is reacted with carbon disulfide or with a thionocarbonic acid derivative X-C(?S)Y, in which X and Y, identically or differently, denote a leaving group.

Description

EXAMPLES

Synthesis Examples

[0174] Abbreviations: [0175] dist. distilled [0176] DABCO 1,4-Diazabicyclo[2.2.2]octane [0177] THF Tetrahydrofuran [0178] MTB ether Methyl-tert-butyl ether [0179] XPhos 2-Dicyclohexylphosphino-2,4,6-triisopropylbiphenyl [0180] XPhos Pd G2 Chloro(2-dicyclohexylphosphino-2,4,6-triisopropyl-1,1-biphenyl)[2-(2-amino-1,1-biphenyl)palladium (II)

Synthesis Example 1: 4-Butyl-4-[2-(3-Fluoro-4-Isothiocyanato-5-Methylphenyl)Ethynyl]-1,1-biphenyl

Step 1.1: [4-(4-Butylphenyl)Phenyl]Ethynyl-Trimethyl-Silane

[0181] ##STR00282##

[0182] A mixture of 1-bromo-4-(4-butylphenyl)benzene (CAS 63619-54-5, 33.5 g, 116 mmol), triethylamine (135 mL), bis(triphenylphosphine)-palladium(II)-chloride (3.2 g, 4.6 mmol), copper(I)-iodide (530 mg, 2.8 mmol) and trimethylsilyl acetylene (33.6 mL, 237 mmol) is heated at reflux temperature overnight. Then dist. water and MTB-ether are added to the reaction mixture. The layers are separated, and the aqueous layer is extracted with MTB-ether. The combined organic layers are washed with dist. water, dried (sodium sulfate) and concentrated in vacuo. The residue is purified by flash chromatography (heptane) to give [4-(4-butylphenyl)phenyl]ethynyl-trimethyl-silane as an orange solid.

Step 1.2: 1-Butyl-4-(4-Ethynylphenyl)Benzene

[0183] ##STR00283##

[0184] Tetra-n-butylammonium fluoride (113 mL, 1 M in THF) is added slowly to a solution of [4-(4-butylphenyl)phenyl]ethynyl-trimethyl-silane (34.6 g, 113 mmol) in THE (650 mL) at 10? C. The reaction mixture is stirred at room temperature overnight. Then dist. water, hydrochloric acid (1 M) and MTB-ether are added to the reaction mixture. The phases are separated, and the aqueous phase is extracted with MTB-ether. The combined organic phases are washed with brine, dried (sodium sulfate) and concentrated in vacuo. The residue is purified by flash chromatography (heptane) to give 1-butyl-4-(4-ethynylphenyl)benzene as a light yellow solid.

Step 1.3: 4-(2-{4-Butyl-[1,1-Biphenyl]-4-Yl}Ethynyl)-2-Fluoro-6-Methylaniline

[0185] ##STR00284##

[0186] A mixture of 1-butyl-4-(4-ethynylphenyl)benzene (4.0 g, 17 mmol) and 4-bromo-2-fluoro-6-methylaniline (3.6 g, 17 mmol) in diisopropylamine (40 mL) and THE (40 mL) is heated to 70? C. under nitrogen atmosphere. Then XPhos PD G2 (27 mg, 0.03 mmol), XPhos (16 mg, 0.03 mmol) and copper(I)-iodide (3.3 mg, 0.02 mmol) are added, and the reaction mixture is stirred at 70? C. overnight. Then it is filtered and concentrated in vacuo. The residue is purified by flash chromatography (heptane and heptane/MTB-ether) to give 4-(2-{4-butyl-[1,1-biphenyl]-4-yl}ethynyl)-2-fluoro-6-methylaniline as a light brown solid.

Step 1.4: 4-Butyl-4-[2-(3-Fluoro-4-Isothiocyanato-5-Methylphenyl)Ethynyl]-1,1-Biphenyl

[0187] ##STR00285##

[0188] Thiophosgene (1.75 mL, 22 mmol) is added dropwise to a mixture of 4-(2-{4-butyl-[1,1-biphenyl]-4-yl}ethynyl)-2-fluoro-6-methylaniline (7.2 g, 20 mmol) and 1,4-diazabicyclo[2.2.2]octane (5.6 g, 50 mmol) in dichloromethane (75 mL) at 0? C., and the reaction mixture is stirred for 1 h at room temperature. It is hydrolyzed with brine, and the phases are separated. The aqueous phase is washed with dichloromethane, and the combined organic phases are dried (sodium sulfate) and concentrated in vacuo. The residue is purified by flash chromatography (heptane) and crystallization with heptane to give 4-butyl-4-[2-(3-fluoro-4-isothiocyanato-5-methylphenyl)ethynyl]-1,1-biphenyl as pale yellow crystals

[0189] Phase sequence: K 83 SmA 102 N 1721

[0190] ?n=0.4800

[0191] ??=14.4

Synthesis Example 2: 5-[2-(4-Butylphenyl)Ethynyl]-1-Fluoro-2-Isothiocyanato-3-Methylbenzene

Step 2.1: 4-[2-(4-Butylphenyl)Ethynyl]-2-Fluoro-6-Methylaniline

[0192] ##STR00286##

[0193] A solution of 1-butyl-4-ethynylbenzene (CAS 79887-09-5) (3.0 g, 19 mmol) and 4-bromo-2-fluoro-6-methylaniline (CAS 429683-46-5) (3.9 g, 19 mmol) in diisopropylamine (45 mL) and tetrahydrofuran (50 mL) is heated to 70? C. under nitrogen atmosphere. Then XPhos Pd G2 (30 mg, 0.04 mmol), XPhos (18 mg, 0.04 mmol) and copper(I)-iodide (3.6 mg, 0.02 mmol) are added, and the reaction mixture is stirred at 70? C. 72 h. Then it is filtered and concentrated in vacuo. The residue is purified by silica gel chromatography with heptane/toluene to give 4-[2-(4-butylphenyl)ethynyl]-2-fluoro-6-methylaniline as a light brown oil.

Step 2.2: 5-[2-(4-Butylphenyl)Ethynyl]-1-Fluoro-2-Isothiocyanato-3-Methylbenzene

[0194] ##STR00287##

[0195] Thiophosgene (1.5 mL, 20 mmol) is added dropwise to a mixture of 4-[2-(4-butylphenyl)ethynyl]-2-fluoro-6-methylaniline (5.0 g, 18 mmol) and DABCO (5.0 g, 44 mmol) in dichloromethane (65 mL) at 0? C., and the reaction mixture is stirred for 1 h at room temperature. It is hydrolyzed with brine, and the phases are separated. The aqueous phase is washed with dichloromethane, and the combined organic phases are dried (sodium sulfate) and concentrated in vacuo. The residue is purified by silica gel chromatography with heptane and by RP flash chromatography with acetonitrile to give 5-[2-(4-butylphenyl)ethynyl]-1-fluoro-2-isothiocyanato-3-methylbenzene as a colorless oil.

[0196] Phase sequence: Tg-57 I

[0197] ?n=0.3367

[0198] ??=13.2

[0199] ?.sub.1=119 mPas

Synthesis Example 3: 4-[2-(4-Butylphenyl)Ethynyl]-3-Fluoro-4-Isothiocyanato-5-Methyl-1,1-Biphenyl

Step 3.1: 2-Fluoro-6-Methyl-4-(4,4,5,5-Tetramethyl-1,3,2-Dioxaborolan-2-Yl)Aniline

[0200] ##STR00288##

[0201] A mixture of 4-bromo-2-fluoro-6-methylaniline (CAS 429683-46-5, 17.0 g, 83 mmol), potassium acetate (24.5 g, 250 mmol), [1,1-bis(diphenylphosphino)ferrocene]-dichloropalladium(II) (1.8 g, 2.5 mmol) and bis-(pinacolato)-diboron (25.9 g, 100 mmol) in 1,4-dioxane (200 mL) is heated at reflux temperature overnight. Then the reaction is quenched by addition of dist. water and MTB-ether. The phases are separated, and the aqueous phase is extracted with MTB-ether. The combined organic phases are washed with dist. water and brine, dried (sodium sulfate) and concentrated in vacuo.

[0202] The residue is purified by flash chromatography (dichloromethane) to give 2-fluoro-6-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline as an orange oil.

Step 3.2: 4-Bromo-3-Fluoro-5-Methyl-[1,1-Biphenyl]-4-Amine

[0203] ##STR00289##

[0204] A mixture of 2-fluoro-6-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline (12.0 g, 48 mmol), 1-bromo-4-iodobenzene (15.2 g, 53 mmol) and sodium carbonate (12.2 g, 115 mmol) in isopropanol (30 mL), toluene (90 mL) and dist. water (65 mL) is stirred for 1 h under nitrogen atmosphere. Then bis(triphenylphosphino)-palladium(II)-dichloride (993 mg, 1.4 mmol) is added, and the reaction mixture is stirred at reflux temperature overnight. The phases are separated, and the aqueous phase is extracted with toluene. The combined organic phases are washed with dist. water, dried (sodium sulfate) and concentrated in vacuo. The residue is purified by flash chromatography (heptane/MTB-ether) to give 4-bromo-3-fluoro-5-methyl-[1,1-biphenyl]-4-amine as a colorless solid.

Step 3.3:4-[2-(4-Butylphenyl)Ethynyl]-3-Fluoro-5-Methyl-[1,1-Biphenyl]-4-Amine

[0205] ##STR00290##

[0206] A mixture of 1-butyl-4-ethynylbenzene (CAS 79887-09-5, 1.5 g, 10 mmol) and 4-bromo-3-fluoro-5-methyl-[1,1-biphenyl]-4-amine (2.5 g, 9 mmol) in diisopropylamine (25 mL) and THE (25 mL) is slowly heated under nitrogen atmosphere. XPhos PD G2 (15 mg, 0.02 mmol), XPhos (9 mg, 0.02 mmol) and copper(I)-iodide (1.8 mg, 0.01 mmol) are added, the reaction mixture is stirred at reflux temperature for 4 h, is filtered and concentrated in vacuo. The residue is purified by flash chromatography (heptane and toluene) to give 4-[2-(4-butylphenyl)ethynyl]-3-fluoro-5-methyl-[1,1-biphenyl]-4-amine as a colorless solid.

Step 3.4: 4-[2-(4-Butylphenyl)Ethynyl]-3-Fluoro-4-Isothiocyanato-5-Methyl-1,1-Biphenyl

[0207] ##STR00291##

[0208] Thiophosgene (0.6 mL, 8 mmol) is added dropwise to a mixture of 4-[2-(4-butylphenyl)ethynyl]-3-fluoro-5-methyl-[1,1-biphenyl]-4-amine (2.5 g, 7 mmol) and DABCO (2.0 g, 18 mmol) in dichloromethane (25 mL) at 0? C. The reaction mixture is stirred for 1 h at room temperature, is hydrolyzed with brine, and the layers are separated. The aqueous phase is washed with dichloromethane, and the combined organic phases are dried (sodium sulfate) and concentrated in vacuo. The residue is purified by flash chromatography (heptane) and crystallization with heptane to give pale yellow crystals of 4-[2-(4-butylphenyl)ethynyl]-3-fluoro-4-isothiocyanato-5-methyl-1,1-biphenyl.

[0209] Phase sequence: K 73 SmA 172 I.

[0210] ?n=0.4652

[0211] ??=16.5

Synthesis Example 4: 1-Fluoro-2-Isothiocyanato-3-Methyl-5-{2-[4-(4-Propylcyclohexyl)-Phenyl]Ethynyl}Benzene

Step 4.1: 2-Fluoro-6-Methyl-4-{2-[4-(4-Propylcyclohexyl)Phenyl]Ethynyl}Aniline

[0212] ##STR00292##

[0213] A solution of 4-(4-propyl-cyclohexyl)-phenylacetylene (CAS 167858-58-4) (5.4 g, 24 mmol) and 4-bromo-2-fluoro-6-methylaniline (CAS 429683-46-5) (4.6 g, 23 mmol) and diisopropylamine (55 mL) in THE (60 mL) is heated to 70? C. under nitrogen atmosphere. Then XPhos Pd G2 (35 mg, 0.05 mmol), XPhos (21 mg, 0.05 mmol) and copper(I)-iodide (4 mg, 0.02 mmol) are added, and the reaction mixture is stirred at 70? C. overnight. Then it is filtered and concentrated in vacuo. The residue is purified by silica gel chromatography (heptane/methyl tert-butyl ether) to give 2-fluoro-6-methyl-4-{2-[4-(4-propylcyclohexyl)phenyl]ethynyl}aniline as a light brown solid.

Step 4.2: 1-Fluoro-2-Isothiocyanato-3-Methyl-5-{2-[4-(4-Propylcyclohexyl)Phenyl]-Ethynyl}Benzene

[0214] ##STR00293##

[0215] Thiophosgene (1.7 mL, 22 mmol) is added dropwise to a mixture of 2-fluoro-6-methyl-4-{2-[4-(4-propylcyclohexyl)phenyl]ethynyl}aniline (7.0 g, 20 mmol) and DABCO (5.6 g, 50 mmol) in dichloromethane (75 mL) at 0? C., and the reaction mixture is stirred for 1 h at room temperature. It is hydrolyzed with brine, and the phases are separated. The aqueous phase is washed with dichloromethane, and the combined organic phases are dried (sodium sulfate) and concentrated in vacuo. The residue is purified by silica gel chromatography (heptane) and crystallization with heptane. The crude product is purified by flash chromatography (toluene and heptane) and crystallization with heptane to give white crystals of 1-fluoro-2-isothiocyanato-3-methyl-5-{2-[4-(4-propylcyclohexyl)phenyl]ethynyl}benzene.

[0216] Phase sequence: K 89 N 109 I.

[0217] ?n=0.3722

[0218] ??=13.9 In analogy to Synthesis Examples 1 to 4 the following compounds are obtained:

TABLE-US-00005 physical No. Compound parameters 5 [00294] 6 [00295] 7 [00296] 8 [00297] 9 [00298] 10 [00299] 11 [00300] 12 [00301] 13 [00302] 14 [00303] 15 [00304] 16 [00305] 17 [00306] 18 [00307] 19 [00308] 20 [00309] 21 [00310] 22 [00311] 23 [00312] 24 [00313] 25 [00314] 26 [00315] 27 [00316] 28 [00317] 29 [00318] 30 [00319] 31 [00320] 32 [00321] 33 [00322] 34 [00323] 35 [00324] 36 [00325] 37 [00326] 38 [00327] 39 [00328] 40 [00329] 41 [00330] 42 [00331] 43 [00332] 44 [00333] 45 [00334] 46 [00335] 47 [00336] 48 [00337] 49 [00338] 50 [00339] 51 [00340] 52 [00341] 53 [00342] 54 [00343] 55 [00344] 56 [00345] K 130 N 168 I ?n = 0.4249 ?? = 1.5 57 [00346] K 99 N 168 I ?n = 0.4070 ?? = 1.7 58 [00347] 59 [00348] 60 [00349] 61 [00350] 62 [00351] 63 [00352] 64 [00353] 65 [00354] 66 [00355] 67 [00356] 68 [00357] 69 [00358] 70 [00359] 71 [00360] 72 [00361] 73 [00362] 74 [00363] 75 [00364] 76 [00365] 77 [00366] 78 [00367] 79 [00368] 80 [00369] 81 [00370] 82 [00371] 83 [00372] 84 [00373] 85 [00374] 86 [00375] 87 [00376] 88 [00377] 89 [00378] 90 [00379] 91 [00380] 92 [00381] 93 [00382] 94 [00383] 95 [00384] 96 [00385] 97 [00386] 98 [00387] 99 [00388] 100 [00389] 101 [00390] 102 [00391] 103 [00392] 104 [00393] 105 [00394] 106 [00395] 107 [00396] 108 [00397] 109 [00398] 110 [00399]

Application Test

[0219] The nematic liquid crystal host mixture N1, example mixtures M1 to M4 and comparative example mixtures C1 to C4 having the compositions and properties as indicated in the following tables are prepared and characterized with respect to their general physical properties and their applicability in microwave components at 19 GHz and 20? C.

[0220] The comparative mixtures contain compounds known from prior art corresponding to Synthesis Examples 1 to 4 in which the 1-fluoro-2-isothiocyanato-3-methylbenzene head group is replaced with a 1,3-difluoro-2-isothiocyanato-benzene head group.

TABLE-US-00006 Mixture N1 CPG-3-F 12.0% T(N, I) [? C.]: 92.5 CPG-5-F 10.0% ?n [589 nm, 20? C.]: 0.0969 CCEP-3-OT 5.0% n.sub.e [589 nm, 20? C.]: 1.5764 CCEP-5-OT 5.0% n.sub.o [589 nm, 20? C.]: 1.4795 CGPC-3-3 2.0% ?? [1 kHz, 20? C.]: 5.3 CGPC-5-3 2.0% ?.sub.? [1 kHz, 20? C.]: 8.4 CGPC-5-5 2.0% ?.sub.? [1 kHz, 20? C.]: 3.1 CP-6-F 8.0% ?.sub.1 [mPa s, 20? C.]: 128 CP-7-F 6.0% K.sub.1 [pN, 20? C.]: 13.2 CCP-2-OT 8.0% K.sub.3 [pN, 20? C.]: 19.6 CCP-3-OT 12.0% K.sub.3/K.sub.1 [pN, 20? C.]: 1.48 CCP-4-OT 7.0% V.sub.0 [V, 20? C.]: 1.66 CCP-5-OT 11.0% ? [20? C., 19 GHz]: 0.100 CP-5-F 10.0% ?.sub.r, ? [20? C., 19 GHz]: 2.49 ? 100.0% ?.sub.r, ? [20? C., 19 GHz]: 2.24 tan ?.sub.? r, ? [20? C., 19 GHz]: 0.0049 tan ?.sub.? r, ? [20? C., 19 GHz]: 0.0125 ? [20? C., 19 GHz]: 8.0 [0221] Example Mixture M1 consists of 90% of host mixture N1 and 10% of the compound PPTG(1)-4-S of Synthesis Example 1. [0222] Example Mixture M2 consists of 90% of host mixture N1 and 10% of the compound PTG(1)-4-S of Synthesis Example 2. [0223] Example Mixture M3 consists of 90% of host mixture N1 and 10% of the compound PTPG(1)-4-S of Synthesis Example 3. [0224] Example Mixture M4 consists of 90% of host mixture N1 and 10% of the compound CPTG(1)-3-S of Synthesis Example 4. [0225] Comparative Mixture C1 consists of 90% of host mixture N1 and 10% of the compound PPTU-4-S. [0226] Comparative Mixture C2 consists of 90% of host mixture N1 and 10% of the compound PTU-4-S. [0227] Comparative Mixture C3 consists of 90% of host mixture N1 and 10% of the compound PTPU-4-S. [0228] Comparative Mixture C4 consists of 90% of host mixture N1 and 10% of the compound CPTU-3-S.

[0229] The following results are obtained:

TABLE-US-00007 Mixture: ?.sub.r,? tan ?.sub.?r,? ?.sub.r,? tan ?.sub.?r,? ? ? M1 2.647 0.0045 2.305 0.0119 0.13 10.9 C1 2.630 0.0047 2.293 0.0124 0.13 10.4 M2 2.604 0.0052 2.272 0.0128 0.13 10.0 C2 2.572 0.0055 2.249 0.0129 0.13 9.7 M3 2.636 0.0048 2.278 0.0119 0.14 11.4 C3 2.622 0.0046 2.286 0.0123 0.13 10.5 M4 2.590 0.0045 2.264 0.0117 0.13 10.8 C4 2.603 0.0050 2.278 0.0122 0.13 10.2

[0230] It can be seen that the compounds of formula G according to the invention show the same tunability values (t) as the compounds from the state of the art.

[0231] Surprisingly, the specific head group of the compounds according to the invention have improved miscibility with other polar compounds. As these polar compounds in general have limited solubility in a host material, it is possible to increase the overall proportion of compounds with high tunability in a medium and thus to achieve better tunabilities of media for microwave applications by addition of the compounds of formula G.