DE19857506A1 - New liquid crystal cyanohydrin compounds with strongly negative dielectric anisotropy useful in various types of displays, obtained by conversion of ketones - Google Patents

Abstract

New liquid crystal cyanohydrin compounds (I) useful in displays are claimed, as are also cyanohydrin intermediates for the production of (I). New liquid crystal cyanohydrin compounds are of formula (I). Independent claims are also included for their preparation and for novel intermediates of formula (IA). R<1>-(A<1>-Z<1>)m1-(A<2>)m2-Z<2>-(A<3>)m3-Z<3>-X-Z<4>-(A<4>)m4-(Z<5>-A <5>)m5-R<2> (I) X = a group of formula (II); B = a group of formula (IIIA)-(IIIG); A<1> - A<5> = 1,4-phenylene (optionally with 1 or 2 CH groups replaced by N), trans-1,4-cyclohexylene (optionally with 1 or 2 CH groups replaced by O and/or S), cyclobutan-1,3-diyl, spiro(3.3)heptan-2,6-diyl or dispiro(3.1.3.1)decan-2,8-diyl, with each of these groups optionally having 1-4 H substituted by F, Cl, CN or 1-7C (optionally F- or Cl-substituted) alkyl, alkoxy or alkylcarbonyl, or with A<3> optionally also being a group of formula (IV); m1 - m5 = 0, 1 or 2, with their sum being 1, 2 or 3; Z<1>, Z<3> and Z<5> = CH2O, OCH2, COO, OCO, CH2CH2, CF2CF2, CF=CF, CH=CH, C?=C or a single bond; Z<2> = as for Z<1> or is CO or CH2 when A<2> = a group of formula (IV); Z<4> = CO or CH2; R<1> = 1-12C alkyl or, when m1 and m2 = 0 and Z<2> = a single bond, optionally also a group of formula -(Y)m6-Q-R<3>, with the 1-12C alkyl optionally having one or more CH2 groups replaced by O, CO, COO, OCO, CF2, CH=CH, CF=CF, C?=C, CF=CFH, CH=CF2 or CF=CF2 , such that the O atoms are not directly bonded to each other; R<2> = as for R<1> or F, Cl, CN, NCS, CF3, OCF2H, OCF3, SF5 or, when m4 and m5 = 0 and Z<2> = a single bond, also a group of formula -(Y)m6-Q-R<3>; Y = CO or CH2; m6 = 0 or 1; Q = 2-20C straight chain alkylene with at least one CH2 group replaced by CH=CH and optionally with further CH2 groups replaced by O, CO, CF2, CH=CH, CF=CF or C?=C such that the O atoms are not directly bonded to each other; R<3> = H, F or Cl; there also being the proviso that B is other than a group of formula (IIID) when m1 - m4 = 0, Z<2> and Z<3> = a single bond, Z<4> = CO, R<1> = 1-10C alkyl, R<2> = 1-10C alkyl or alkoxy, F, Cl or CN and (Z<5>-A<5>)m5 = Phe, Cyc, Phe-Phe, Phe-Cyc, Phe-Dio, Cyc-Cyc or Phe-COO-Phe where Phe = 1,4-phenylene, Cyc = trans-1,4-cyclohexylene and Dio = 1,3-dioxan-2,5-diyl.

Description

The invention relates to new liquid-crystalline cyanohydrin derivatives Process for their preparation, as well as in this process resulting intermediates. The invention also relates to Use of the liquid crystalline cyanohydrin derivatives in liquid crystalline media and liquid crystal displays (FKA), as well liquid crystalline media and FKA's containing the new ones Cyanohydrin derivatives.

Liquid crystals with negative dielectric anisotropy (Δε) are for certain electro-optical FKA's, especially displays from the ECB (electrically controlled birefringence), IPS (in plane switching) or VA (vertically aligned) TFT type, the basis of the image display. The display types developed based on these liquid crystals are mainly characterized by an improved Viewpoint independence of the contrast and the colors of the displayed images.

Previously known liquid crystals with negative dielectric Anisotropy are e.g. B. Cyclohexane derivatives with axial nitrile group according to DE 32 31 707 or R. Eidenschink, Angew. Chemistry 96, 151 (1984); Appl. Chem. Int. Ed. Engl. 23, 151 (1984). The one in these However, connections described in documents are not sufficient always meet the requirements, especially when used in FKA of the above type of dielectric negative liquid crystals be placed such. B. a strongly negative Δε and at the same time high clearing point.

The task was therefore to create new liquid-crystalline compounds to provide that for use in FKA's, especially in FKA's of the ECB, IPS and VA-TFT type are suitable. The new In particular, connections should have a highly negative dielectric Anisotropy and at the same time the highest possible clearing point exhibit.  

This object has been achieved according to the invention by provision liquid-crystalline cyanohydrin derivatives according to claim 1.

Liquid crystalline cyanohydrin derivatives are described in JP 61-10544 A2 described, but have the compounds disclosed therein partially no or only monotropic nematic phase behavior and low clearing points. Compounds according to the main claim of This application is not covered by JP 61-10544 A2.

The invention thus relates to liquid-crystalline cyanohydrin derivatives of the formula I.

R ¹ - (A ¹ -Z ¹ ) _m1 - (A ² ) _m2 -Z ² - (A ³ ) _m3 -Z ³ -XZ ⁴ - (A ⁴ ) _m4 - (Z ⁵ -A ⁵ ) _m5 -R ² I.

where the individual groups have the following meaning

A ¹ to A ⁵ each independently of one another 1,4-phenylene, in which one or two CH groups can also be replaced by N, trans-1,4-cyclohexylene, in which one or two CH ₂ groups can also be replaced by O and / or S can be replaced, cyclobutane-1,3-diyl, spiro [3.3] heptane-2,6-diyl, or Dispiro [3.1.3.1] decane-2,8-diyl, 1 to 4 H- in these groups also Atoms can be replaced by F, Cl, CN or unsubstituted or mono- or polysubstituted by F or Cl alkyl, alkoxy or alkylcarbonyl with 1 to 7 carbon atoms,
A ³ if necessary

m ₁ to m ₅ each independently of one another 0, 1 or 2, where m ₁ + m ₂ + m ₃ + m ₄ + m ^{5 is} 1, 2 or 3,
Z ¹ , Z ³ and Z ⁵ each independently of one another CH ₂ O, OCH ₂ , COO, OCO, CH ₂ CH ₂ , CF ₂ CF ₂ , CF = CF, CH = CH, C∼C or a single bond,
Z ^{2 has} one of the meanings given for Z ¹ , or, if A ²

means CO or CH ₂ ,
Z ⁴ CO or CH ₂ ,
R ^{1 is} an alkyl group with 1 to 12 carbon atoms, in which one or more CH ₂ groups can also be replaced by O, CO, COO, OCO, CF ₂ , CH = CH, CF = CF, C∼C, that O atoms are not directly linked to one another, -CF = CFH, -CH = CF ₂ , -CF = CF ₂ or, if ml and m ² 0 and Z ^{2 represent} a single bond, optionally also - (Y) _m6 -QR ³ ,
R ^{2 has} one of the meanings given for R ¹ , F, Cl, CN, NCS, CF ₃ , OCF ₂ H, OCF ₃ , SF ₅ or, if m ₄ and m ₅ 0 and Z ^{4 represent} a single bond, optionally also - ( Y) _m6 -QR ³ ,
Y CO or CH ₂ ,
m ₆ 0 or 1,
Q straight-chain alkylene with 2 to 20 C atoms, in which at least one CH ₂ group is replaced by CH = CH, and optionally further CH ₂ groups by O, CO, CF ₂ , CH = CH, CF = CF or C∼ C can be replaced so that O atoms are not directly linked,
R ³ H, F or Cl,
with the proviso that if m1, m ₂ , m ₃ and m ₄ 0, Z ² and Z ^{3 are} a single bond, Z ⁴ CO, R ^{1 is} an alkyl group having 1 to 10 C atoms, R ^{2 is} an alkyl or alkoxy group with 1 to 10 C atoms, F, Cl or CN, (Z ⁵ -A ⁵ ) _m5 Phe, Cyc, Phe-Phe, Phe-Cyc, Phe-Dio, Cyc-Cyc or Phe-COO-Phe, and Phe 1,4-phenylene, cyc trans-1,4-cyclohexylene and dio 1,3-dioxane-2,5-divl mean
B one of

has different meanings.

Another object of the invention is the use of Compounds of formula I in liquid crystalline media and Liquid crystal displays.

Another object of the invention are liquid crystal displays containing a liquid crystalline medium with at least two liquid crystalline components, at least one of which Component is a compound of formula I.

In particular, the cyanohydrin esters of formula I (in which Z ⁴ = CO) have, in comparison z. B. with structurally analogous cyanohydrin compounds with directly linked ring groups, a strongly negative Δε.

Particular preference is given to compounds of the formula I in which A ¹ to A ^{5 are} each independently of one another

and L ¹ and L ² each independently represent H or F.

Further preferred compounds of formula I are those in which

and Z ³ denotes a single bond,

means.

Compounds of the formula Ia are particularly preferred

wherein
alkyl is an alkyl group with 1 to 8 carbon atoms,
Z ⁴ CO or CH ₂ ,

m ₄ 0 or 1, and
R is an alkyl or alkoxy group with 1 to 8 C atoms or an alkenyl group with 2 to 7 C atoms
mean.

Compounds of the formula Ia in which m is 1 and Z ^{4 is} CO are particularly preferred. These compounds are distinguished, particularly in comparison to the structurally analogous compounds with an inverse ester group, by particularly high clearing points, which would otherwise only be expected from liquid-crystalline compounds with four ring groups.

Also preferred are compounds of the formula I or according to one of the preferred embodiments mentioned above, in which R ¹ and / or R ^{2 are} alkyl, alkoxy or alkenyl having 1 to 10 C atoms.

Z ¹ , Z ² , Z ³ and Z ⁵ in formula I are particularly preferably each independently of the other -COO-, -OCO-, -CH ₂ CH ₂ -, -OCH ₂ -, -CH ₂ O-, -CH = CH -, -C∼C- or a single bond, in particular -COO-, -OCO-, -CH ₂ CH ₂ - or a single bond.

L ¹ and L ^{2 are} preferably F, Cl, CN, NO ₂ , CH ₃ , C ₂ H ₅ , OCH ₃ , OC ₂ H ₅ , COCH ₃ , COC ₂ H ₅ , CF ₃ , OCF ₃ , OCHF ₂ , OC ₂ F ₅ , in particular F, Cl, CN, CH ₃ , C ₂ H ₅ , OCH ₃ , COCH ₃ and OCF ₃ , particularly preferably F, Cl, CH ₃ , OCH ₃ and COCH ₃ .

Particularly preferred sub-formulas for formula I are listed below. In these preferred formulas, Phe means 1,4-phenylene, which can additionally be substituted in the 2-, 3- and / or 5-position by L ¹ and / or L ² as indicated above. Furthermore, Pyd means pyridine-2,5, -diyl, pyr pyrimidine-2,5-diyl, Cyc 1,4-cyclohexylene, which can also be substituted in the 4-position by L ¹ and dio trans-1,3-dioxane 2,5-diyl. The heterocycles Pyd, Pyr and Dio each also include the possible positional isomers.

X 'means in these formulas

R ¹ , R ² and X have the meaning given in formula I. Z has one of the meanings given for Z ¹ , Z ² , Z ³ and Z ⁵ in formula I. W and W 'are independently CO or CH ₂ . The following list of preferred formulas also includes their mirror images.

R ¹ -Phe-ZXWR ² I 1-1

R ¹ -Cyc-ZXWR ² I 1-2

R ¹ -Pyd-ZXWWR ² I 1-3

R ¹ -Pyr-ZXWR ² I 1-4

R ¹ -Dio-ZXWR ² I 1-5

R ¹ -XW-Phe-R ² I 1-6

R ¹ -XW-Cyc-WR ² I 1-7

R ¹ -XW-Pyd-R ² I 1-8

R ¹ -XW-Pyr-R ² I 1-9

R ¹ -XW-Dio-WR ² 1-10

R ¹ -W'-X'-ZXWR ² I 1-11

R ¹ -Phe-Z-Phe-ZXWR ² I 2-1

R ¹ -Cyc-Z-Phe-ZXWR ² I 2-2

R ¹ -Phe-Z-Cyc-ZXWR ² I 2-3

R ¹ -Cyc-Z-Cyc-ZXWR ² I 2-4

R ¹ -Phe-ZP yd-ZXWR ² I 2-5

R ¹ -Pyr-Z-Phe-ZXWR ² I 2-6

R ¹ -Phe-Z-Pyr-ZXWR ² I 2-7

R ¹ -Phe-Z-Dio-ZXWR ² I 2-8

R ¹ -Dio-Z-Dio-ZXWR ² I 2-9

R ¹ -Cyc-Z-Dio-ZXWWR ² I 2-10

R ¹ -Phe-ZXW-Phe-R ² I 2-11

R ¹ -Cyc-ZXWZ-Phe-R ² I 2-12

R ¹ -Cyc-ZXWZ-Cyc-R ² I 2-13

R ¹ -Phe-ZXWZ-Pyr-R ² I 2-14

R ¹ -Phe-ZXWZ-Pyd-R ² I 2-15

R ¹ -Phe-ZXWZ-Dio-WR ² I 2-16

R ¹ -Cyc-ZXWZ-Dio-R ² I 2-17

R ¹ -Dio-ZXWZ-Dio-WR ² I 2-18

R ¹ -XW-Phe-Z-Phe-R ² I 2-19

R ¹ -XW-Cyc-Z-Phe-R ² I 2-20

R ¹ -XW-Phe-Z-Cyc-R ² I 2-21

R ¹ -XW-Cyc-Z-Cyc-R ² I 2-22

R ¹ -XW-Phe-Z-Pyd-R ² I 2-23

R ¹ -XW-Pyr-Z-Phe-WR ² I 2-24

R ¹ -XW-Phe-Z-Pyr-WR ² I 2-25

R ¹ -XWP he-Z-Dio-R ² I 2-26

R ¹ -XW-Dio-Z-Dio-R ² I 2-27

R ¹ -XW-Cyc-Z-Dio-R ² I 2-28

R ¹ -Phe-W'-X'-ZXWR ² I 2-29

R ¹ -Cyc-W'-X'-ZXWR ² I 2-30

R ¹ -Pyr-W'-X'-ZXWR ² I 2-31

R ¹ -Pyd-W'-X'-ZXWR ² I 2-32

R ¹ -Dio-W'-X'-ZXWR ² I 2-33

R ¹ -Phe-Z-Phe-Z-Phe-ZXWR ² I 3-1

R ¹ -Cyc-Z-Phe-Z-Phe-ZXWR ² I 3-2

R ¹ -Phe-Z-Cyc-Z-Phe-ZXWR ² I 3-3

R ¹ -Cyc-Z-Cyc-Z-Phe-ZXWR ² I 3-4

R ¹ -Phe-Z-Phe-Z-Cyc-ZXWR ² I 3-5

R ¹ -Cyc-Z-Phe-Z-Cyc-ZXWWR ² I 3-6

R ¹ -Phe-Z-Cyc-Z-Cyc-ZXWR ² I 3-7

R ¹ -Cyc-Z-Cyc-Z-Cyc-ZXWR ² I 3-8

R ¹ -Pyr-Z-Phe-Z-Phe-ZXWR ² I 3-9

R ¹ -Phe-Z-Pyr-Z-Phe-ZXWR ² I 3-10

R ¹ -Phe-Z-Phe-Z-Pyr-ZXWR ² I 3-11

R ¹ -Pyd-Z-Phe-Z-Phe-ZXWR ² I 3-12

R ¹ -Phe-Z-Pyd-Z-Phe-ZXWR ² I 3-13

R ¹ -Dio-Z-Phe-Z-Phe-ZXWWR ² I 3-14

R ¹ -Phe-Z-Dio-Z-Phe-ZXWR ² I 3-15

R ¹ -Phe-Z-Phe-Z-Dio-ZXWR ² I 3-16

R ¹ -Dio-Z-Cyc-Z-Cyc-ZXWWR ² I 3-17

R ¹ -Cyc-Z-Dio-Z-Cyc-ZXWR ² I 3-18

R ¹ -Cyc-Z-Cyc-Z-Dio-ZXWR ² I 3-19

R ¹ -Dio-Z-Dio-Z-Cyc-ZXWR ² I 3-20

R ¹ -Phe-Z-Phe-ZXWZ-Phe-R ² I 3-21

R ¹ -Cyc-Z-Phe-ZXWZ-Phe-R ² I 3-22

R ¹ -Phe-Z-Cyc-ZXWZ-Phe-R ² I 3-23

R ¹ -Phe-Z-Phe-ZXWZ-Cyc-R ² I 3-24

R ¹ -Cyc-Z-Cyc-ZXWZ-Phe-R ² I 3-25

R ¹ -Cyc-Z-Phe-ZXWZ-Cyc-WR ² I 3-26

R ¹ -Phe-Z-Cyc-ZXWZ-Cyc-R ² I 3-27

R ¹ -Cyc-Z-Cyc-ZXWZ-Cyc-WR ² I 3-28

R ¹ -Pyr-Z-Phe-ZXWZ-Phe-R ² I 3-29

R ¹ -Phe-Z-Pyr-ZXWZ-Phe-R ² I 3-30

R ¹ -Phe-Z-Phe-ZXWZ-Pyr-R ² I 3-31

R ¹ -Pyd-Z-Phe-ZXWZ-Phe-R ² I 3-32

R ¹ -Phe-Z-Pyd-ZXWZ-Phe-R ² I 3-33

R ¹ -Dio-Z-Phe-ZXWZ-Phe-R ² I 3-34

R ¹ -Phe-Z-Dio-ZXWZ-Phe-R ² I 3-35

R ¹ -Phe-Z-Phe-ZXWZ-Dio-R ² I 3-36

R ¹ -Dio-Z-Cyc-ZXWZ-Cyc-WR ² I 3-37

R ¹ -Cyc-Z-Dio-ZXWZ-Cyc-R ² I 3-38

R ¹ -Cyc-Z-Cyc-ZXWZ-Dio-R ² I 3-39

R ¹ -Dio-Z-Dio-ZXWZ-Cyc-WR ² I 3-40

R ¹ -Phe-ZXW-Phe-Z-Phe-R ² I 3-41

R ¹ -Cyc-ZXW-Phe-Z-Phe-WR ² I 3-42

R ¹ -Phe-ZXW-Cyc-Z-Phe-R ² I 3-43

R ¹ -Cyc-ZXW-Cyc-Z-Phe-R ² I 3-44

R ¹ -Phe-ZXW-Phe-Z-Cyc-R ² I 3-45

R ¹ -Cyc-ZXW-Phe-Z-Cyc-R ² I 3-46

R ¹ -Phe-ZXW-Cyc-Z-Cyc-R ² I 3-47

R ¹ -Cyc-ZXW-Cyc-Z-Cyc-R ² I 3-48

R ¹ -XW-Phe-Z-Phe-Z-Phe-R ² I 3-49

R ¹ -XW-Cyc-Z-Phe-Z-Phe-R ² I 3-50

R ¹ -XW-Phe-Z-Cyc-Z-Phe-WR ² I 3-51

R ¹ -XW-Cyc-Z-Cyc-Z-Phe-R ² I 3-52

R ¹ -XW-Phe-Z-Phe-Z-Cyc-R ² I 3-53

R ¹ -XW-Cyc-ZP he-Z-Cyc-R ² I 3-54

R ¹ -XW-Phe-Z-Cyc-Z-Cyc-WR ² I 3-55

R ¹ -XW-Cyc-Z-Cyc-Z-Cyc-R ² I 3-56

R ¹ -Phe-Z-Phe-W'-X'-ZXWR ² I 3-57

R ¹ -Phe-Z-Cyc-W'-X'-ZXWR ² I 3-58

R ¹ -Cyc-Z-Phe-W'-X'-ZXWR ² I 3-59

R ¹ -Cyc-Z-Cyc-W'-X'-ZXWWR ² 3-60

R ¹ -Cyc-Z-Dio-W'-X'-ZXWR ² I 3-61

R ¹ -Phe-Z-Py r-W'-X'-ZXWR ² I 3-62

R ¹ -Phe-W'-X'-ZXW-Phe-R ² I 3-63

R ¹ -Cyc-W'-X'-ZXW-Cyc-R ² I 3-64

R ¹ -Phe-W'-X'-ZXW-Cyc-R ² I 3-65

R ¹ -Phe-W'-X'-ZXW-Pyr-R ² I 3-66

R ¹ -Cyc-W'-X'-ZXW-Dio-R ² I 3-67

The compounds of the formulas I 1-1, I 1-2, I 1-11, I 2-1 to I 2-4, I 2-11 to I 2-13, I 2-29, I 2-30, I 3-1 to I 3-8, I 3-57 to I 3-60, and I 3-63 to I 3-65.

Of the compounds of the formulas I 1-6, I 3-64 and I 3-65, those are particularly preferred in which W and W 'or R ¹ and R ² each have the same meaning.

Z in the preferred formulas of the series I 1-, I 2- and I 3- given above preferably denotes -COO-, -OCO-, -CH ₂ CH ₂ -, -OCH ₂ -, -CH ₂ O-, -CH = CH-, -C∼C- or a single bond, in particular -COO-, -OCO-, -CH ₂ CH ₂ - or a single bond.

If Phe is substituted 1,4-phenylene, this is preferably substituted one or more times by L ¹ and / or L ² according to one of the preferred meanings mentioned above. It is preferably 2- or 3-fluoro, 2,3-difluoro, 3,5-difluoro, 2- or 3-chloro, 2- or 3-methyl, 2,3-dimethyl, 2- or 3-methoxy-, 2- or 3-trifluoromethyl-, 2- or 3-trifluoromethoxy-, 2- or 3-methylcarbonyl-, 2- or 3-cyano- or 2,3-dicyano-1,4-phenylene. Substituted 1,4-cyclohexylene is preferably 4-cyano-1,4-cyclohexylene. For 1,4-cyclohexylene, the trans configuration is generally preferred.

Compounds of the formula I in which R F, Cl, CN or unsubstituted or one or more times by fluorine substituted alkyl, alkoxy or alkenyl with up to 12 C atoms means.

If R ¹ and R ² in the compounds of the formula I are an alkyl radical or an alkoxy radical, this can be straight-chain or branched. It is preferably straight-chain, has 2, 3, 4, 5, 6 or 7 carbon atoms and accordingly preferably means ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentoxy, hexoxy or heptoxy, furthermore methyl , Octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octoxy, nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy or tetradecoxy.

Oxaalkyl preferably means straight-chain 2-oxapropyl (= Methoxymethyl), 2- (= ethoxymethyl) or 3-oxabutyl (= 2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-, 3-, 4-, 5- or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.

If R ¹ or R ^{2 is} an alkyl radical in which a CH ₂ group has been replaced by -CH = CH-, this can be straight-chain or branched. It is preferably straight-chain and has 2 to 10 carbon atoms. Accordingly, it means especially vinyl, prop-1-, or prop-2-enyl, but-1-, 2- or but-3-enyl, pent-1-, 2-, 3- or pent-4-enyl, hex -1-, 2-, 3-, 4- or hex-5-enyl, hept-1-, 2-, 3-, 4-, 5- or hept-6-enyl, oct-1-, 2-, 3-, 4-, 5-, 6- or oct-7-enyl, non-1-, 2-, 3-, 4-, 5-, 6-, 7- or non-8-enyl, Dec-1 -, 2-, 3-, 4-, 5-, 6-, 7-, 8- or Dec-9-enyl.

Particularly preferred alkenyl groups are C ₂ -C ₇ -1E-alkenyl, C ₄ -C ₇ -3E-alkenyl, C ₅ -C ₇ -4-alkenyl, C ₆ -C ₇ -5-alkenyl and C ₇ -6-alkenyl , in particular C ₂ -C ₇ -1E-alkenyl, C ₄ -C ₇ -3E-alkenyl and C ₅ -C ₇ -4-alkenyl. Examples of particularly preferred alkenyl groups are vinyl, 1E-propenyl, 1E-butenyl, 1E-pentenyl, 1E-hexenyl, 1E-heptenyl, 3-butenyl, 3E-pentenyl, 3E-hexenyl, 3E-heptenyl, 4-pentenyl, 42-hexenyl , 4E-hexenyl, 42-heptenyl, 5-hexenyl, 6-heptenyl and the like. Groups of up to 5 carbon atoms are generally preferred.

If R ¹ or R is an alkyl radical in which one CH ₂ group has been replaced by -O- and one has been replaced by -CO-, these groups are preferably adjacent. Thus, they include an acyloxy group -CO-O- or an oxycarbonyl group -O-CO-. These are preferably straight-chain and have 2 to 6 carbon atoms.

Accordingly, they mean especially acetyloxy, propionyloxy, Butyryloxy, pentanoyloxy, hexanoyloxy, acetyloxymethyl, Propionyloxymethyl, butyryloxymethyl, pentanoyloxymethyl, 2-acetyloxyethyl, 2-propionyloxyethyl, 2-butyryloxyethyl, 3-acetyloxypropyl, 3-propionyloxypropyl, 4-acetyloxybutyl, Methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, Pentoxycarbonyl, methoxycarbonylmethyl, ethoxycarbonylmethyl, Propoxycarbonylmethyl, butoxycarbonylmethyl, 2- (methoxycarbonyl) ethyl, 2- (ethoxycarbonyl) ethyl, 2- (propoxy carbonyl) ethyl, 3- (methoxycarbonyl) propyl, 3- (ethoxycarbonyl) propyl, 4- (methoxycarbonyl) butyl.

If R ¹ or R ^{2 represents} an alkyl radical in which two or more CH ₂ groups have been replaced by -O- and / or -CO-O-, this can be straight-chain or branched. It is preferably branched and has 3 to 12 carbon atoms. Accordingly, it means especially bis-carboxy-methyl, 2,2-bis-carboxy-ethyl, 3,3-bis-carboxy-propyl, 4,4-bis-carboxy-butyl, 5,5-bis-carboxy-pentyl, 6,6-bis-carboxy-hexyl, 7,7-bis-carboxy-heptyl, 8,8-bis-carboxy-octyl, 9,9-bis-carboxy-nonyl, 10,10-bis-carboxy-decyl, Bis (methoxycarbonyl) methyl, 2,2-bis (methoxycarbonyl) ethyl, 3,3-bis (methoxycarbonyl) propyl, 4,4-bis (methoxycarbonyl) butyl, 5,5-bis (methoxycarbonyl) pentyl, 6,6-bis (methoxycarbonyl) hexyl, 7,7-bis (methoxycarbonyl) heptyl, 8,8-bis (methoxycarbonyl) octyl, bis (ethoxycarbonyl) methyl, 2,2-bis (ethoxycarbonyl) ethyl, 3,3-bis (ethoxycarbonyl) propyl, 4,4-bis (ethoxycarbonyl) butyl, 5,5-bis (ethoxycarbonyl) hexyl.

If R ¹ or R ^{2 is} an alkyl or alkenyl radical which is simply substituted by CN or CF ₃ , this radical is preferably straight-chain. The substitution by CN or CF ₃ is in any position.

If R ¹ or R ^{2 is} an alkyl or alkenyl radical which is at least monosubstituted by halogen, this radical is preferably straight-chain and halogen is preferably F or Cl. In the case of multiple substitution, halogen is preferably F. The resulting residues also include perfluorinated residues. In the case of single substitution, the fluorine or chlorine substituent can be in any position, but preferably in the ω position. Examples of particularly preferred straight-chain groups with terminal fluorine are fluoromethyl, 2-fluoroethyl, 3-fluoropropyl, 4-fluorobutyl, 5-fluoropentyl, 6-fluorohexyl and 7-fluoroheptyl. However, other positions of the fluorine are not excluded.

Compounds of the formula I with branched wing groups R ¹ or R ² can occasionally be of importance because of their better solubility in the customary liquid-crystalline base materials, but in particular as chiral dopants if they are optically active. Smectic compounds of this type are suitable as components for ferroelectric materials.

Compounds of the formula I with S _A phases are suitable, for example, for thermally addressed displays.

Preferred chiral branched radicals R ¹ and R ² are 2-butyl (= 1-methylpropyl), 2-methylbutyl, 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-propylpentyl, 2-octyl, in particular 2-methylbutyl, 2 - Methylbutoxy, 2-methylpentoxy, 3-methylpentoxy, 2-ethylhexoxy, 1-methylhexoxy, 2-octyloxy, 2-oxa-3-methylbutyl, 3-oxa-4-methylpentyl, 4-methylhexyl, 2-nonyl, 2-decyl , 2-dodecyl, 6-methoxyoctoxy, 6-methyloctoxy, 6-methyloctanoyloxy, 5-methylheptyloxycarbonyl, 2-methylbutyryloxy, 3-methylvaleroyloxy, 4-methylhexanoyloxy, 2-chloropropionyloxy, 2-chloro-3-methylbutyryloxy, 2-chloro-4 -methylvaleryloxy, 2-chloro-3-methylvaleryloxy, 2-methyl-3-oxapentyl, 2-methyl-3-oxahexyl, 1-methoxypropyl-2-oxy, 1-ethoxypropyl-2-oxy, 1-propoxypropyl-2-oxy , 1-butoxypropyl-2-oxy, 2-fluorooctyloxy, 2-fluorodecyloxy.

Compounds of the formula I containing an achiral branched group R ¹ or R ² can also be of importance as co-components in liquid-crystalline media, for example to suppress the tendency to crystallize. Branched groups of this type usually contain no more than one chain branch. Preferred achiral branched groups are, for example, isopropyl, isobutyl (= methylpropyl), isopentyl (= 3-methylbutyl), isopropoxy, 2-methylpropoxy and 3-methylbutoxy. The compounds of the formula I can be synthesized in accordance with the preferred method described below by using a ketone of the formula IV

converted in a known manner to a cyanohydrin of the formula II

and then the cyanohydrin of the formula II with an acid derivative of the formula IIIa

U ¹ -Z ⁴ - (A ⁴ ) _m4 (Z ⁵ -A ⁵ ) _m5 -R ² IIIa

or a functional alkane of the formula IIIb

U ² -Z ⁴ - (A ⁴ ) _m4 - (Z ⁵ -A ⁵ ) _m5 -R ² IIIb

can react to a product of formula I
where R ¹ , R ² , A ¹ to A ⁵ , Z ¹ , Z ² , Z ³ , Z ⁵ , m ₁ to m ₅ and B have the meaning given in formula I,
Z ⁴ in formula IIIa CO and in formula IIIb CH ₂ ,
U ¹ Cl, Br, OH or -OZ ⁴ - (A ⁴ ) _m4 - (Z ⁵ -A ⁵ ) _m5 -R ² , and
U ² Cl, Br, J, OH, OSO ₂ , CH ₃ , p-toluenesulfonyl, OSO ₂ CH ₃ or OSO ₂ C ₄ F ₉
mean.

The manufacturing method described above and below of compounds of formula I is a further subject of Invention.

The compounds of formula IIIa, IIIb and IV are known and can according to known and in the literature, for. Tie Standard works such as Houben-Weyl, Methods of Organic Chemistry (Georg-Thieme-Verlag, Stuttgart) described methods getting produced.

Thus, from the acids of formula IIIa (U ¹ = OH), the acid halides (U ¹ = Cl, Br) or anhydrides (U ¹ = -OZ ⁴ - (A4) m ₄ - (Z ⁵ -A ⁵ ) represent _m5 -R ² ) which can be reacted in the presence of a base to give the cyanohydrin esters of the formula I (in which Z ⁴ = CO). The acids can also simply in the presence of a dehydrating agent, for. B. cyclohexylcarbodiimide, directly to the cyanohydrin esters.

In the simplest case, the functional alkanes of the formula IIIb can be obtained by reducing the acids of the formula IIIa with complex aluminum hydrides to the alcohols (U = OH), either directly by means of a Mitsunobu reaction or after conversion of the OH groups into another leaving group U ² (e.g. Cl, Br, J, OSO ₂ OCF ₃ ) are implemented, e.g. B. according to the method of B. Jursic, Tetrahedron 44, 6677 (1980).

In the preparation of the compounds of the formula I in which A ³

and Z ^{3 represents} a single bond, the cyanohydrin of the formula IIb

first etherified "left" in the manner indicated above and then "right" etherified or esterified.

The cyanohydrins of formula II and IIb are new and another The invention also relates to its use as a precursor for Synthesis of liquid crystalline compounds.

In the compounds of the formula II, the radicals R ¹ , R ² , A ¹ , A ² , A ³ , Z ¹ , Z ² , Z ³ , m ₁ , m ₂ , m ₃ and B preferably have the preferred meanings as for formula I specified.

Cyanohydrins of the formula IIa are particularly preferred

wherein alkyl and B have the meaning given in formula Ia.

The synthesis of the cyanohydrins II, IIa and ILb is carried out in a known manner Manner using the in Houben-Weyl, methods of Organic Chemistry, Ketone II, Volume 7/26, pp. 1963-1965 (Georg- Thieme-Verlag, Stuttgart 1976) specified methods, such as Reaction of the ketones with liquid hydrocyanic acid, with those generated in situ Hydrocyanic acid (from KCN, acetocyanhydrin) or by means of Trimethylsilyl cyanide in the presence of a Lewis acid. Variants of the the latter method have been published recently, so e.g. B. in Y. Yang, D. Wang, Synlett 1997, 1397 and M. Mori, H. Imma, T. Nakai, Tetrahedron Letters 38, 6229 (1997).

Other particularly suitable and preferred methods for Preparation of the compounds of formula I can be found in the following examples.  

The compounds of formula I according to the invention are also suitable for use as components of liquid crystalline media.

Liquid-crystalline media according to the invention preferably contain in addition to one or more compounds of the invention Formula I as further constituents 2 to 40, in particular 4 to 30 Components. These media contain very particularly preferably in addition to one or more compounds 7 to 25 components. These other ingredients are preferred selected from nematic or nematogenic (monotropic or isotropic) substances, especially substances from the classes Azoxybenzenes, Benzylidenanüine, Biphenyle, Terphenyle, Phenyl or cyclohexyl benzoates, cyclohexane carboxylic acid phenyl or cyclohexyl ester, phenyl or cyclohexyl ester of cyclo hexylbenzoic acid, phenyl or cyclohexyl ester of cyclo hexylcyclohexane carboxylic acid, cyclohexyl phenyl ester of Benzoic acid, cyclohexane carboxylic acid, or cyclohexyl cyclohexane carboxylic acid, phenylcyclohexane, cyclohexylbiphenyl, Phenylcyclohexylcyclohexane, cyclohexylcyclohexane, cyclo hexylcyclohexylcyclohexenes, 1,4-bis-cyclohexylbenzenes, 4,4'-bis- cyclo-hexylbiphenyls, phenyl- or cyclohexylpyrimidines, phenyl- or cyclohexylpyridines, phenyl- or cyclohexyldioxanes, phenyl- or cyclohexyl-1,3-dithiane, 1,2-diphenylethane, 1,2-dicyclohexyl ethane, 1-phenyl-2-cyclohexylethane, 1-cyclohexyl-2- (4-phenyl cyclohexyl) ethane, 1-cyclohexyl-2-biphenylylethane, 1-phenyl 2-cyclohexyl-phenylethanes, optionally halogenated stilbenes, Benzylphenyl ether, tolanes and substituted cinnamic acids. The 1,4- Phenylene groups in these compounds can also be fluorinated.

The most important compounds which are suitable as further constituents of media according to the invention can be characterized by the formulas 1, 2, 3, 4 and 5:

R'-LER "1

R'-L-COO-ER "2nd

R'-L-OOC-ER "3

R'-L-CH ₂ CH ₂ -ER "4

R'-L-C∼C-E-R "5

In formulas 1, 2, 3, 4 and 5, L and E are the same as or can be different, each independently one bivalent residue from the from -Phe-, -Cyc-, -Phe-Phe-, -Phe-Cyc-, -Cyc-Cyc-, -Pyr-, -Dio-, -G-Phe- and -G-Cyc- as well as their Mirror images formed group, where Phe unsubstituted or 1,4-phenylene substituted by fluorine, Cyc trans-1,4-cyclohexylene or 1,4-cyclohexylene, pyr pyrimidine-2,5-diyl or pyridine-2,5-diyl, Dio 1,3-dioxane-2,5-diyl and G2- (trans-1,4-cyclohexyl) ethyl, Pyrimidine-2,5-diyl, pyridine-2,5-diyl or 1,3-dioxane-2,5-diyl.

One of the radicals L and E is preferably Cyc, Phe or Pyr. E is preferably Cyc, Phe or Phe-Cyc. Preferably contain the media according to the invention one or more components selected from the compounds of the formulas 1, 2, 3, 4 and 5, wherein L and E are selected from the group Cyc, Phe and Pyr and selected one or more components at the same time the compounds of formulas 1, 2, 3, 4 and 5, wherein one of the Residues L and E is selected from the group Cyc, Phe and Pyr and the other residue is selected from the group -Phe-Phe-, -Phe-Cyc-, -Cyc-Cyc-, -G-Phe- and -G-Cyc-, and optionally one or more components selected from the compounds of the formulas 1, 2, 3, 4 and 5, in which the radicals L and E are selected are from the group -Phe-Cyc-, -Cyc-Cyc-, -G-Phe- and -G-Cyc-.

R 'and R "mean in a smaller subset of the compounds of the formulas 1, 2, 3, 4 and 5 each independently of one another alkyl, Alkenyl, alkoxy, alkoxyalkyl, alkenyloxy or alkanoyloxy with up to 8 carbon atoms. The following is this smaller subset Group A and the compounds are called with the sub-formulas 1a, 2a, 3a, 4a and 5a. Most of these Compounds R 'and R "are different from each other, one these radicals are mostly alkyl, alkenyl, alkoxy or alkoxyalkyl.  

In another smaller subgroup, referred to as group B, of the compounds of the formulas 1, 2, 3, 4 and 5, R "means -F, -Cl, -NCS or - (O) _i CH ₃ - _{(k + l)} F _k Cl _l , where i is 0 or 1 and k + 1, 1, 2 or 3; the compounds in which R "has this meaning are denoted by the sub-formulas 1b, 2b, 3b, 4b and 5b. Particularly preferred are those compounds of the sub-formulas 1b, 2b, 3b, 4b and 5b in which R "has the meaning -F, -Cl, -NCS, -CF ₃ , -OCHF ₂ or -OCF ₃ .

In the compounds of sub-formulas 1b, 2b, 3b, 4b and 5b, R 'has that meaning given for the compounds of the sub-formulas 1a-5a and is preferably alkyl, alkenyl, alkoxy or alkoxyalkyl.

In another smaller subset of the compounds of the Formulas 1, 2, 3, 4 and 5 mean R "-CN; this subgroup is described in hereinafter referred to as group C and the compounds of these Subgroups are accordingly with sub-formulas 1c, 2c, 3c, 4c and 5c. In the compounds of sub-formulas 1c, 2c, 3c, 4c and 5c has R 'that in the compounds of sub-formulas 1a-5a indicated meaning and is preferably alkyl, alkoxy or Alkenyl.

In addition to the preferred compounds of groups A, B and C. also other compounds of the formulas 1, 2, 3, 4 and 5 with others Variants of the proposed substituents are common. All these Substances are based on methods known from the literature or in analogy available for this.

In addition to the compounds of the formula I, the media according to the invention preferably contain one or more compounds which are selected from group A and / or group B and / or group C. The mass fractions of the compounds from these groups in the media according to the invention are preferred
Group A: 0 to 90%, preferably 20 to 90%, in particular 30 to 90%
Group B: 0 to 80%, preferably 10 to 80%, in particular 10 to 65%
Group C: 0 to 80%, preferably 5 to 80%, in particular 5 to 50%
wherein the sum of the mass fractions of the compounds from groups A and / or B and / or C contained in the respective media according to the invention is preferably 5% to 90% and in particular 10% to 90%.

The media according to the invention preferably contain 1 to 40%, particularly preferably 5 to 30% of compounds of the formula I. Media containing more than 40% are also preferred. in particular 45 to 90% of compounds of formula I. The media preferably contain 1 to 5, particularly preferably 2, 3, 4 or 5 Compounds of formula I.

The production of the liquid crystal which can be used according to the invention Mixtures are carried out in a conventional manner. As a rule, the desired amount of those used in smaller quantities Components in the main constituent Components dissolved, expediently at elevated temperature. It is also possible solutions of the components in an organic Solvents, e.g. B. in acetone, chloroform or methanol mix and the solvent after mixing again remove, for example by distillation.

The liquid-crystal media can also be used by those skilled in the art contain known additives described in the literature. For example, 0-15% or pleochroic dyes chiral dopants are added.

The compounds of formula I according to the invention are suitable as Components of liquid crystalline media, especially for Liquid crystal displays based on the principle of the twisted cell, the Guest-host effect, the effect of the deformation of aligned phases  or based on static or dynamic scatter, continue in cholesteric or ferroelectric liquid crystal displays or IPS (in plane switching), polymer gel or PDLC displays (polymer dispersed liquid crystal displays).

The compounds according to the invention are particularly preferred in liquid crystal media with negative dielectric anisotropy as well used in FKA's containing such media as B. Ads from ECB, OCB (optically compensated bend mode), CSH (color super homeotropic mode) and IPS type, as well as in ads based on the DAP (deformation of aligned phases) or VA (vertically aligned) Effect based, such. B. VAN- (vertically aligned nematic) and VAC (vertically aligned cholesteric) displays. Especially active matrix displays of the above-mentioned types, such as TFT (thin film transistor), MOS (metal oxide semiconductor) and MIM (metal insulator metal) displays.

The following examples are intended to illustrate the invention without limiting it. Unless otherwise stated, all percentages above and below mean percentages by weight; all temperatures are given in degrees Celsius. Δn denotes the optical anisotropy and n _o the ordinary refractive index (each at 589 nm and 20 ° C). Δε denotes the dielectric anisotropy and ε 'the dielectric constant perpendicular to the longitudinal axis of the molecule.

The following abbreviations are also used:
K = crystalline, N = nematic, S = smectic, I = isotropic, the numbers between these symbols indicate the phase transition temperatures in ° C. Numbers in parentheses indicate monotropic phase transitions.

Furthermore mean
RT = room temperature
DCC = dicyclohexylcarbodiimide
DMAP = N, N-dimethylaminopyridine
DCM = dichloromethane

example 1 Preparation of a cyanohydrin

22.668 g (0.1 mol) of 4'-propyl-bicyclohexyl-4-one are at RT in 50 ml 2-methyllactonitrile dissolved and stirred for 4 h. After adding one Spatula tip sodium carbonate is approximately three days until extensive Implementation stirred. The approach is at 2 mbar and 95 ° C Bath temperature rotated in and the residue in a ratio of 1: 3 Hexane at -20 ° C and again in a ratio of 1: 4 from hexane recrystallized. 4-Hydroxy-4'-propyl-bicyclohexyl-4- is obtained. carbonitrile (purity GC: 99.4%).

The following compounds are prepared in an analogous manner
4-hydroxy-4'-ethyl-bicyclohexyl-4-carbonitrile
4-hydroxy-4'-butyl-bicyclohexyl-4-carbonitrile
4-hydroxy-4'-pentyl-bicyclohexyl-4-carbonitrile

Example 2 Preparation of a cyanohydrin

97.138 g (0.5 mol) of bicyclohexyl-4,4'-dione are at RT in 250 ml of 2- Dissolved methyl lactic acid nitrile and stirred for three days at RT. To Adding a spatula tip of sodium carbonate is another three days stirred until largely implemented. The separated one thick precipitate is filtered off after cooling to -20 ° C and with wash some toluene. The 4,4'-dihydroxy thus obtained bicyclohexyl-4,4'-dicarbonitrile is directly reacted further.  

Example 3 Preparation of a cyanohydrin

28.045 g (0.20 mol) of 4-propylcyclohexanone are at RT in 100 ml DCM dissolved and at -20 ° C 30.14 ml (0.24 mol) trimethylsilyl cyanide admitted. Then under cooling at a maximum of -20 ° C 4.386 ml (0.04 mol) of titanium (IV) chloride were added dropwise and the mixture was stirred at RT for 2 hours touched. 100 ml of water and 100 ml of DTM are added to the mixture admitted. The mixture is dissolved by the undissolved over diatomaceous earth suction filtered, the organic phase separated and evaporated. That so The 1-hydroxy-4-propyl-cyclohexylcarbonitrile obtained is passed on directly implemented.

The following compounds are prepared in an analogous manner
1-hydroxy-4-ethyl-cyclohexylcarbonitrile
1-hydroxy-4-butylcyclohexylcarbonitrile
1-hydroxy-4-pentylcyclohexylcarbonitrile

Example 4 Preparation of a cyanohydrin ester

12.470 g (0.050 mol) of 4-hydroxy-4'-propyl-bicyclohexyl-4-carbonitrile from Example 1, 8.513 g (0.050 mol) of 4-propyl-cyclohexane carboxylic acid and 0.611 g (0.005 mol) of DMAP are placed in 100 ml of toluene and then a solution of 11.348 g (0.055 mol) of DCC in 50 ml of toluene was added dropwise at 5 to 10 ° C. The cooling bath is then removed and the mixture is stirred at RT overnight. The next day, the resulting dicyclohexylurea is suctioned off and concentrated using a rotary evaporator. The residue is fritted with toluene over silica gel (No. 7729) and the eluate is spun in. The product is fractionally fritted again, as described above, first with hexane, then quantitatively with toluene (TLC control). After spinning in, the product fractions are recrystallized from 100 ml of hexane at 5 ° C. 4-Propyl-cyclohexanecarboxylic acid 4-cyano-4'-propyl-bicyclohexyl-4yl ester (HPLC purity: 99.5%) is obtained. K 48 S _B 225 N 277: 8 I, Δε = -9, Δn = 0.066.

The following connections are made in an analogous manner
4-Propyl-cyclohexane carboxylic acid 4-cyano-4'-ethyl-bicyclohexyl-4yl ester
4-Propyl-cyclohexane carboxylic acid 4-cyano-4'-butyl-bicyclohexyl-4yl ester
4-Propyl-cyclohexane carboxylic acid 4-cyano-4'-pentyl-bicyclohexyl-4yl ester
4-ethyl-cyclohexane carboxylic acid 4-cyano-4'-propyl-bicyclohexyl-4yl ester
4-ethyl-cyclohexane carboxylic acid 4-cyano-4'-pentyl-bicyclohexyl-4yl ester
4-Butyl-cyclohexanecarboxylic acid 4-cyano-4'-ethyl-bicyclohexyl-4yl ester
4-Butyl-cyclohexane carboxylic acid 4-cyano-4'-butyl-bicyclohexyl-4y1 ester
4-Pentyl-cyclohexane carboxylic acid 4-cyano-4'-propyl-bicyclohexyl-4yl ester
4-pentyl-cyclohexane carboxylic acid 4-cyano-4'-pentyl-bicyclohexyl-4yl ester
Propanoic acid 4-cyano-4'-propyl-bicyclohexyl-4yl ester (K 45 I, Δε = -11.1, Δn = 0.040)
Propanoic acid 4-cyano-4'-butyl-bicyclohexyl-4yl ester
Propanoic acid 4-cyano-4'-pentyl-bicyclohexyl-4yl ester
Butanoic acid 4-cyano-4'-ethyl-bicyclohexyl-4yl ester
Butanoic acid 4-cyano-4'-propyl-bicyclohexyl-4yl ester
4-cyano-4'-pentylbicyclohexyl-4yl butanoate
Pentanoic acid 4-cyano-4'-propyl-bicyclohexyl-4yl ester
4-cyano-4'-butyl-bicyclohexyl-4yl pentanoate
Pentanoic acid 4-cyano-4'-pentyl-bicyclohexyl-4yl ester

Example 5 Preparation of a cyanohydrin ester

12.470 g (0.050 mol) of 4-hydroxy-4'-propyl-bicyclohexyl-4-carbonitrile from Example 1, 8.210 g (0.050 mol) of 4-propylbenzoic acid and 0.611 g (0.005 mol) DMAP are placed in 100 ml of toluene and then at 5 to 10 ° C a solution of 11.348 g (0.055 mol) DCC in 50 ml Toluene added dropwise. The cooling bath is then removed and over Stirred at RT overnight. Then 1 g of oxalic acid is added and stirred another hour. Then the resulting Aspirated dicyclohexylurea and evaporated. The backlog will fractionally fried with toluene over silica gel (No. 7729) (DC Control), and the clean product fractions are spun in. The the remaining product is eluted quantitatively with toluene. Subsequently is recrystallized in a ratio of 1: 3 from hexane at -20 ° C. Man receives 4-propylbenzoic acid 4-cyano-4'-propyl-bicyclohexyl-4yl ester (HPLC purity: 99.9%). K 87 N 87.7 I, Δε = -10.1, Δn = 0.067

The following connections are made in an analogous manner
4-Propylbenzoic acid 4-cyano-4'-ethyl-bicyclohexyl-4yl ester
4-Propylbenzoic acid 4-cyano-4'-butyl-bicyclohexyl-4yl ester
4-Propylbenzoic acid 4-cyano-4'-pentyl-bicyclohexyl-4yl ester
4-pentylbenzoic acid 4-cyano-4'-propyl-bicyclohexyl-4yl ester
4-pentylbenzoic acid 4-cyano-4'-propyl-bicyclohexyl-4yl ester
4-pentylbenzoic acid 4-cyano-4'-butyl-bicyclohexyl-4yl ester
4-pentylbenzoic acid 4-cyano-4'-pentyl-bicyclohexyl-4yl ester
2,3-difluoro-4-ethylbenzoic acid 4-cyano-4'-ethyl-bicyclohexyl-4yl ester
2,3-difluoro-4-ethylbenzoic acid 4-cyano-4'-propyl-bicyclohexyl-4yl ester (K 144 N (136.2) I)
2,3-difluoro-4-ethylbenzoic acid 4-cyano-4'-butyl-bicyclohexyl-4yl ester
2,3-difluoro-4-ethylbenzoic acid 4-cyano-4'-pentyl-bicyclohexyl-4yl ester (K 115 N 135.7 I, Δε = -6.1, An = 0.105)
2,3-difluoro-4-propylbenzoic acid 4-cyano-4'-ethyl-bicyclohexyl-4yl ester
2,3-difluoro-4-propylbenzoic acid 4-cyano-4'-butyl-bicyclohexyl-4yl ester
2,3-difluoro-4-propylbenzoic acid 4-cyano-4'-pentyl-bicyclohexyl-4yl ester

Example 6 Preparation of a cyanohydrin ester

12.416 g (0.050 mol) of 4,4'-dihydroxybicyclohexyl-4,4'-dicarbonitrile from Example 2, 9.178 ml (0.100 mol) butyric acid and 1.222 g (0.010 mol) DMAP are placed in 250 ml of toluene and then at 5 to 10 ° C a solution of 22.696 g (0.110 mol) DCC in 50 ml toluene dripped. The cooling bath is then removed and left overnight stirred at RT. Then 1 g of oxalic acid is added and one stirred another hour. Then the resulting Aspirated dicyclohexylurea and evaporated. The backlog will fritted with toluene over silica gel (No. 7729) and the eluate was evaporated. The residue is recrystallized from heptane / toluene 1: 1 at 5 ° C and the product again in a ratio of 1: 5 from MTB ether at 5 ° C recrystallized. 4'-Butanoyloxy-4,4'-dicyano- butanoic acid is obtained. bicyclohexyl-4-yl ester (HPLC purity: 99.6%). K 121 I

The following connections are made in an analogous manner
Propanoic acid 4'-propanoyloxy-4,4'-dicyano-bicyclohexyl-4-yl ester
4'-Pentanoyloxy-4,4'-dicyano-bicyclohexyl-4-yl pentanoate
4'-propanoyloxy-4,4'-dicyano-bicyclohexyl-4-yl butanoate
4'-pentanoyloxy-4,4'-dicyano-bicyclohexyl-4-yl butanoic acid ester
Propanoic acid 4'-ethanoyloxy-4,4'-dicyano-bicyclohexyl-4-yl ester
4'-Butanoyloxy-4,4'-dicyano-bicyclohexyl-4-yl propanoate
Propanoic acid 4'-pentanoyloxy-4,4'-dicyano-bicyclohexyl-4-yl ester
Pentanoic acid 4'-ethanoyloxy-4,4'-dicyano-bicyclohexyl-4-yl ester
4'-propanoyloxy-4,4'-dicyano-bicyclohexyl-4-yl pentanoate
4'-Butanoyioxy-4,4'-dicyano-bicyclohexyl-4-yl ester of pentanoate
4'-Pentanoyloxy-4,4'-dicyano-bicyclohexyl-4-yl pentanoate

Example 7 Preparation of a cyanohydrin ester

16.725 g (0.100 mol) of 1-hydroxy-4-propylcyclohexylcarbonitrile from Example 3, 25.240 g (0.100 mol) and 1.222 g (0.010 mol) of DMAP are placed in 100 ml of toluene and then a solution of at 5 to 10 ° C. 22.696 g (0.055 mol) of DCC in 50 ml of toluene were added dropwise. The cooling bath is then removed and the mixture is stirred at RT overnight. The resulting dicyclohexylurea is then suctioned off and concentrated using a rotary evaporator. The residue is fritted with toluene over silica gel (No. 7729) and the eluate is spun in. The residue is recrystallized twice from 100 ml of hexane at -20 ° C. 4'-Propyl-bicyclohexyl-4-carboxylic acid-1-cyano-4-propyl-cyclohexyl ester is obtained (HPLC purity: 100%). K 39 S _B 118 N 126 I, Δε = -6.9, Δn = 0.034

The following connections are made in an analogous manner
4'-ethyl-bicyclohexyl-4-carboxylic acid 1-cyano-4-ethyl-cyclohexyl ester
4'-ethyl-bicyclohexyl-4-carboxylic acid 1-cyano-4-propyl-cyclohexyl ester
4'-ethyl-bicyclohexyl-4-carboxylic acid 1-cyano-4-butyl-cyclohexyl ester
4'-ethyl-bicyclohexyl-4-carboxylic acid-1-cyano-4-pentylcyclohexyl ester
4'-Propyl-bicyclohexyl-4-carboxylic acid 1-cyano-4-ethyl-cyclohexyl ester
4'-Propyl-bicyclohexyl-4-carboxylic acid 1-cyano-4-butyl-cyclohexyl ester
4'-Propyl-bicyclohexyl-4-carboxylic acid 1-cyano-4-pentylcyclohexyl ester
4'-Butyl-bicyclohexyl-4-carboxylic acid 1-cyano-4-ethyl-cyclohexyl ester
4'-Butyl-bicyclohexyl-4-carboxylic acid 1-cyano-4-propyl-cyclohexyl ester
4'-Butyl-bicyclohexyl-4-carboxylic acid 1-cyano-4-butyl-cyclohexyl ester
4'-Butyl-bicyclohexyl-4-carboxylic acid-1-cyano-4-pentylcyclohexyl ester
4'-Pentyl-bicyclohexyl-4-carboxylic acid 1-cyano-4-ethylcyclohexyl ester
4'-Pentyl-bicyclohexyl-4-carboxylic acid 1-cyano-4-propyl-cyclohexyl ester
4'-Pentyl-bicyclohexyl-4-carboxylic acid 1-cyano-4-butyl-cyclohexyl ester
4'-Pentyl-bicyclohexyl-4-carboxylic acid 1-cyano-4-pentyl-cyclohexyl ester

Example 8 Preparation of a cyanohydrin ether

30,800 g (0.100 mol) of 4-hydroxy-4'-pentyl-bicyclohexyl-4-carbonitrile (prepared as described in Example 1), 8.460 ml (0.100 mol) 3- Bromine-1-propene, 1.822 g (0.005 mol) N-cetyl-N, N, N- trimethylammonium bromide, 8,000 g (0.200 mol) sodium hydroxide and 50 ml of THF are combined, mixed with 0.5 ml of water and stirred overnight at 70 ° C. Then that will The reaction mixture is evaporated in a rotary evaporator, the residue is toluene-coated over silica gel (No. 7729) and the eluate is evaporated. The backlog is in Ratio 1: 3 recrystallized from hexane at -80 ° C and  then cleaned chromatographically. You get 4-prop-2- enyloxy-4'-pentyl-bicyclohexyl-4-carbonitrile.

The following connections are made in an analogous manner
4-vinyloxy-4'-pentyl-bicyclohexyl-4-carbonitrile
4-but-3-enyloxy-4'-pentyl-bicyclohexyl-4-carbonitrile
4-pent-4-enyloxy-4'-pentyl-bicyclohexyl-4-carbonitrile
4-hex-5-enyloxy-4'-pentyl-bicyclohexyl-4-carbonitrile
4-hept-6-enyloxy-4'-pentyl-bicyclohexyl-4-carbonitrile
4-vinyloxy-4'-ethyl-bicyclohexyl-4-carbonitrile
4-prop-2-enyloxy-4'-ethyl-bicyclohexyl-4-carbonitrile
4-but-3-enyloxy-4'-ethyl-bicyclohexyl-4-carbonitrile
4-pent-4-enyloxy-4'-ethyl-bicyclohexyl-4-carbonitrile
4-vinyloxy-4'-propyl-bicyclohexyl-4-carbonitrile
4-prop-2-enyloxy-4'-propyl-bicyclohexyl-4-carbonitrile
4-but-3-enyloxy-4'-propyl-bicyclohexyl-4-carbonitrile
4-pent-4-enyloxy-4'-propyl-bicyclohexyl-4-carbonitrile
4-vinyloxy-4'-butyl-bicyclohexyl-4-carbonitrile
4-prop-2-enyloxy-4'-butyl-bicyclohexyl-4-carbonitrile
4-but-3-enyloxy-4'-butyl-bicyclohexyl-4-carbonitrile
4-pent-4-enyloxy-4'-butyl-bicyclohexyl-4-carbonitrile

Claims (10)

1. Liquid crystalline compounds of the formula I.
R ¹ - (A ¹ -Z ¹ ) _m1 - (A ² ) m ² -Z ² - (A ³ ) m ₃ -Z ³ -XZ ⁴ - (A ⁴ ) _m4 - (Z ⁵ -A ⁵ ) _m5 - R ² I
where the individual groups have the following meaning
A ¹ to A ⁵ each independently of the other 1,4-phenylene, in which one or two CH groups can also be replaced by N, trans-1,4-cyclohexylene, in which one or two CH ₂ groups can also be replaced by O and / or S can be replaced, cyclobutane-1,3-diyl, spiro [3.3] heptane-2,6-diyl, or Dispiro [3.1.3.1] decane-2,8-diyl, 1 to 4 H- in these groups also Atoms can be replaced by F, Cl, CN or unsubstituted or mono- or polysubstituted by F or Cl alkyl, alkoxy or alkylcarbonyl having 1 to 7 carbon atoms,
A ³ if necessary
m ₁ to m ₅ each independently of one another 0, 1 or 2, where m ₁ + m ₂ + m ₃ + m ₄ + m _{5 is} 1, 2 or 3,
Z ¹ , Z ³ and Z ⁵ each independently of one another CH ₂ O, OCH ₂ , COO, OCO, CH ₂ CH ₂ , CF ₂ CF ₂ , CF = CF, CH = CH, C∼C or a single bond,
Z ^{2 has} one of the meanings given for Z ¹ , or, if A ²
means CO or CH ₂ ,
Z ⁴ CO or CH ₂ ,
R ^{1 is} an alkyl group with 1 to 12 carbon atoms, in which one or more CH ₂ groups can also be replaced by O, CO, COO, OCO, CF ₂ , CH = CH, CF = CF, C∼C, that O atoms are not directly linked, -CF = CFH, -CH = CF ₂ , -CF = CF ₂ or, if m ₁ and m ₂ 0 and Z ^{2 represent} a single bond, optionally also - (Y) _m6 -QR ³ ,
R ^{2 has} one of the meanings given for R ¹ , F, Cl, CN, NCS, CF ₃ , OCF ₂ H, OCF ₃ , SF ₅ or, if m ₄ and m ₅ 0 and Z ^{4 represent} a single bond, optionally also - (Y) _m6 -QR ³ ,
Y CO or CH ₂ ,
m ₆ 0 or 1,
Q straight-chain alkylene with 2 to 20 C atoms, in which at least one CH ₂ group is replaced by CH = CH, and optionally further CH ₂ groups by O, CO, CF ₂ , CH = CH, CF = CF or C = C can be replaced so that O atoms are not directly linked,
R ³ H, F or Cl,
with the proviso that if m ₁ , m ₂ , m ₃ and m ₄ 0, Z ² and Z ^{3 are} a single bond, Z ⁴ CO, R ^{1 is} an alkyl group having 1 to 10 carbon atoms, R ^{2 is} an alkyl or Alkoxy group with 1 to 10 carbon atoms, F, Cl or CN, (Z ⁵ -A ⁵ ) _m5 Phe, Cyc, Phe-Phe, Phe-Cyc, Phe-Dio, Cyc-Cyc or Phe-COO-Phe, and Phe is 1,4-phenylene, Cyc trans-1,4-cyclohexylene and dio 1,3-dioxane-2,5-diyl,
B one of
has different meanings. 2. Compounds according to claim 1, wherein A ¹ to A ⁵ each independently
and L ¹ and L ² each independently represent H or F. 3. Compounds according to any one of claims 1 and 2, wherein A ³
and Z ³ denotes a single bond. 4. Compounds according to any one of claims 1 and 2, selected from formula Ia
wherein
alkyl is an alkyl group with 1 to 8 carbon atoms,
Z ⁴ CO or CH ₂ ,
m ₄ 0 or 1, and
R is an alkyl or alkoxy group with 1 to 8 C atoms or an alkenyl group with 2 to 7 C atoms
mean. 5. Compounds according to any one of claims 1 to 4, wherein B
means. 6. Compounds according to any one of claims 1 to 5, wherein R ¹ and / or R ^{2 is} alkyl, alkoxy or alkenyl having 1 to 10 carbon atoms. 7. A process for the preparation of compounds of formula I by using a ketone of formula IV
converted in a known manner to a cyanohydrin of the formula II
and then the cyanohydrin of the formula II with an acid derivative of the formula IIIa
U ¹ -Z ⁴ - (A ⁴ ) _m4 (Z ⁵ -A ⁵ ) _m5 -R ² IIIa
or a functional alkane of the formula IIIb
U ² -Z ⁴ - (A ⁴ ) _m4 - (Z ⁵ -A ⁵ ) _m5 -R ² IIIb
can react to a product of formula I
where R ¹ , R ² , A ¹ to A ⁵ , Z ¹ , Z ² , Z ³ , Z ⁵ , m ₁ to m ₅ and B have the meaning given in formula I,
Z ⁴ in formula IIIa CO and in formula IIIb CH ₂ ,
U ¹ Cl, Br, OH or -OZ ⁴ - (A ⁴ ) m ₄ - (Z ⁵ -A ⁵ ) _m5 -R ² , And
U ² Cl, Br, J, OH, OSO ₂ , CH ₃ , p-toluenesulfonyl, OSO ₂ CH ₃ or OSO ₂ C ₄ F ₉
mean. 8. Cyanohydrin of the formula II
wherein R ¹ , R ² , A ¹ , A ² , A ³ , Z ¹ , Z ² , Z ³ , m ₁ , m ₂ , m ₃ and B have the meaning given in formula I, as a precursor for the synthesis of liquid-crystalline compounds . 9. Use of compounds according to one of claims 1 to 6 in liquid crystalline media and liquid crystal displays. 10. Liquid crystal display containing a liquid crystalline medium with at least two liquid crystalline components, of which at least one component connects is one of claims 1 to 6.