GB2271351A - Carbocyclyl-phenyl-pyrazines and liquid crystalline media - Google Patents
Carbocyclyl-phenyl-pyrazines and liquid crystalline media Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D241/00—Heterocyclic compounds containing 1,4-diazine or hydrogenated 1,4-diazine rings
- C07D241/02—Heterocyclic compounds containing 1,4-diazine or hydrogenated 1,4-diazine rings not condensed with other rings
- C07D241/10—Heterocyclic compounds containing 1,4-diazine or hydrogenated 1,4-diazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members
- C07D241/12—Heterocyclic compounds containing 1,4-diazine or hydrogenated 1,4-diazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to ring carbon atoms
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D241/00—Heterocyclic compounds containing 1,4-diazine or hydrogenated 1,4-diazine rings
- C07D241/02—Heterocyclic compounds containing 1,4-diazine or hydrogenated 1,4-diazine rings not condensed with other rings
- C07D241/10—Heterocyclic compounds containing 1,4-diazine or hydrogenated 1,4-diazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members
- C07D241/14—Heterocyclic compounds containing 1,4-diazine or hydrogenated 1,4-diazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D241/16—Halogen atoms; Nitro radicals
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D241/00—Heterocyclic compounds containing 1,4-diazine or hydrogenated 1,4-diazine rings
- C07D241/02—Heterocyclic compounds containing 1,4-diazine or hydrogenated 1,4-diazine rings not condensed with other rings
- C07D241/10—Heterocyclic compounds containing 1,4-diazine or hydrogenated 1,4-diazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members
- C07D241/14—Heterocyclic compounds containing 1,4-diazine or hydrogenated 1,4-diazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D241/18—Oxygen or sulfur atoms
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K19/00—Liquid crystal materials
- C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
- C09K19/06—Non-steroidal liquid crystal compounds
- C09K19/34—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring
- C09K19/3441—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having nitrogen as hetero atom
- C09K19/345—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having nitrogen as hetero atom the heterocyclic ring being a six-membered aromatic ring containing two nitrogen atoms
- C09K19/3452—Pyrazine
Abstract
Phenylpyrazines of the formula I, <IMAGE> wherein R<1> and R2 are an alkyl group of 1-15 C atoms (wherein one or two non-adjacent CH2 groups can also be replaced by O atoms and/or -CO- groups and/or @@@@ -O-CO-groups and/ or -CO-O- groups and/or -O-COO- groups and/or -CH(halogen)-groups) @@@@ and one of R<1> or R<2> may also be @@@@ Q-Y, (wherein Y is H, F or Cl; and Q is @@@@ -CF2-, @@@@ -CF2CF2-, -OCF2-, @@@@ -OCF2CF2- or a single bond); <IMAGE> is a a trans-1,4-cyclohexylene group or a @@@@ 1,4-phenylene group which is unsubstituted or monosubstituted or polysubstituted by F @@@@ and/or Cl atoms; and x 0, 1 or 2,] and also to liquid crystalline media being a mixture of at least 2 compounds, characterized in that at least one compound is a phenylpyrazine according to formula I.
Description
Phenvlpvrazines The invention relates to phenylpyrazines of the formula I,
wherein
R1 and R2 are an alkyl group of 1-15 C atoms, wherein one or
two non-adjacent CH2 groups can also be replaced by O atoms and/or -CO- groups and/or -O-CO-groups and/
or -CO-O- groups and/or -O-COO- groups and/or
-CH-halogen groups, and one of R1 or R2 may be Q-Y,
wherein Y is H, F or Cl, and Q is -CF2-, -CF2CF2-,
-OCF2-, -OCF2CF2- or a single bond.
is a a trans-1,4-cyclohexylene group or a 1,4phenylene group which is unsubstituted or monosubstituted or polysubstituted by F and/or Cl atoms, and x 0, 1 or 2, and also to liquid crystalline media being a mixture of at least 2 compounds, characterized in that at least one compound is a phenylpyrazine according to formula I.
The invention was based on the object of discovering new stable liquid crystal or mesogenic compounds which are suitable as components of liquid crystalline media and, in particular, have advantageous values for optical and dielectric anisotropy combined with low viscosity and high nematogenity.
Compounds containing the structural unit
are mentioned in the USP 4,913,837.
It has now been found that the compounds of formula I are highly suitable as polar components of liquid crystalline media. In particular, they have especially advantageous values of optical and dielectric anisotropy and are not strongly smectogenic. It is also possible to obtain stable liquid crystal phases with a broad nematic mesophase range including a good deep temperature behaviour, a high resistivity and a comparatively low viscosity with the aid of these compounds.
Depending on the choice of R1, R2,
and x, the compounds of the formula I can be used as the base materials from which liquid crystal media are predominantly composed; however, it is also possible for compounds of the formula I to be added to liquid crystal base materials of other classes of compounds, for example in order to influence the dielectric and/or optical anisotropy and/or the viscosity and/or the nematic range of such a dielectric.
The compounds of the formula I are in particular suitable as components for liquid crystal media for displays which are based on the principle of polymer dispersed liquid crystals (pdlc) or polymer liquid crystals (pnlc) due to their favorable optical anisotropy and the dielectric anisotropy.
The compounds of the formula I are colourless in the pure state and are liquid crystalline in a temperature range which is favourably placed for electrooptical use. They are very stable towards chemicals, heat and light.
The invention thus relates to the phenylpyrazines of the formula I, to liquid crystalline media with at least two liquid crystalline components, wherein at least one component is a compound of the formula I and to liquid crystal display devices containing such media.
Above and below, R1, R2,
and x have the meaning given unless expressly indicated otherwise.
The compounds of the formula I include phenylpyrazines of the formulae Ia to Ii (L1-4 = H or F):
Thereof those of the partial formula Ia, Id, Ih and Ii are particularly preferred.
The preferred compounds of the partial formula Ia comprise those of the partial formula Iaa to Iat
Thereof those of the partial formula Iaa, Iab, Iac, Iad, Iaf,
Iag, Iam and Ian are particularly preferred.
The preferred compounds of the partial formula Ib comprise those of the partial formula Iba to Ibr
Thereof those of the partial formulae Iba, Ibb, Ibc, Ibd,
Ibg, Ibh, Ibm and Ibr are particularly preferred.
The preferred compounds of the partial formula Ic comprise those of the partial formulae Ica to Icr.
Thereof those of the partial formulae Ica, Icb, Icc, Icd, Icg, Ich, Icm and Icn are particularly preferred.
The preferred compounds of the partial formula Id comprise those of the partial formulae Ida to Idf.
R1 is preferably alkyl, F or Cl. The alkyl group can exhibit a straight-chain or branched structure.
R2 is preferably F, Cl, alkyl, alkoxy, CF3 or OCF3.
Alkyl or alkoxy preferably are straight-chain and have 2, 3, 4, 5, 6 or 7 C atoms. Accordingly they are preferably ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentoxy, hexoxy or heptoxy, also ethyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octoxy, nonoxy, decoxy, undecoxy, tridecoxy or tetradecoxy.
If R and/or R2 are oxaalkyl it is preferably straight-chain 2-oxypropyl (= methoxymethyl), 2-(= ethoxymethyl) or 3-oxybutyl (= 2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-, 3-, 4-, 5- or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl or 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.
is preferably
If
is a trans-1,4-cyclohexylene group, R1 is preferably alkyl. In the case that
is a 1,4-phenylene group which may be substituted by F RI is preferably alkyl, F or C1.
Compounds of the formula I containing a branched terminal group can occasionally be of importance because of an improved solubility in the customary liquid crystal base materials, but in particular as chiral doping substances if they are optically active.
Branched groups of this type as a rule contain not more than one chain branching. Preferred branched radicals are isopropyl, 2-butyl (= 1-methylpropyl), isobutyl (= 2-methylpropyl), 2-methylbutyl, isopentyl, (= 3-methylbutyl), 2-methylpentyl, 2-ethylhexyl, 2-propylpentyl, 2-octyl, isopropoxy, 2-methylpropoxy, 2-methylbutoxy, 3-methylbutoxy, 2-methylpentoxy, 3-methylpentoxy, 2-ethylhexoxy, 2-methylhexoxy, 1-methylhexoxy, 1-methylheptoxy (= 2-octy'.oxy), 2-oxa-3-methylbutyl, 3-oxy-4-methylpentyl, 4-methylhexyl, 2-nonyl, 2-decyl, 2-dodecyl, 6-methyloctoxy, oxy, 2-methyl-3-oxapentyl and 2-methyl-3-oxyhexyl.
In the case of compounds with a branched terminal group Ri and/or R21 formula I includes both the optical antipodes and racemates as well as mixtures thereof.
Of the compounds of the formula I and subformulae thereof, those in which at least one of the radicals contained therein has one of the preferred meanings given are preferred.
The compounds of the formula I are prepared by methods which are known per se, such as are described in the literature (for example in the standard works, such as Houben-Weyl,
Methoden der Organischen Chemie [Methods of Organic Chemistry], Georg Thieme Verlag, Stuttgart), and in particular under reaction conditions which are known and suitable for the reactions mentioned. Variants which are known per se and are not mentioned in more detail here can also be used in this connection.
If desired, the starting materials can also be formed in situ, such that they are not isolated from the reaction mixture but are immediately reacted further to give the compounds of the formula I.
Preferred route for preparation of the phenylpyrazines are shown in the following scheme.
Scheme 1:
Scheme 2:
All starting materials are known or prepared in analogy to known starting materials.
Other routes are apparent to the skilled worker. All these steps and the corresponding reaction conditions are known to the skilled worker.
In addition to one or more compounds for formula I the liquid crystal media according to the invention preferably contain 2-40 components and in particular 4-30 components. Liquid crystal media being composed of one or more compounds of formula I and 7-25 other components are especially preferred.
These additional components are preferred chosen from the nematic or nematogenic (monotropic or isotropic) substances; in particular from the classes of azoxybenzenes, benzylideneanilines, biphenyls, terphenyls, phenyl or cyclohexyl benzoates, phenyl or cyclohexyl cyclohexanecarboxylates, phenyl or cyclohexyl cyclohexylbenzoates, phenyl or cyclohexyl cyclohexylcyclohexanecarboxylates, cyclohexylphenylbenzoates, cyclohexylphenyl cyclohexanecarboxylates, cyclohexylphenyl cyclohexylcyclohexanecarboxylates, phenylcyclohexanes, cyclohexylbiphenyls, phenylcyclohexylcyclohexanes, cyclohexylcyclohexanes, cyclohexylcyclohexenes, cyclohexylcyclohexylcyclohexene, 1,4-bis-cyclohexylbenzenes, 4,4'-biscyclohexylbiphenyl, phenyl- or cyclohexylpyrimidines, phenylor cyclohexylpyridines, phenyl- or cyclohexyldioxanes, phenyl -or cyclohexyl-1,3-dithianes, 1,2-diphenylethanes, 1, 2-di- cyclohexylethanes, 1-phenyl-2-cyclohexylethanes, 1-cyclo hexyl-2-(4-phenyl-cyclohexyl)-ethas, l-cyclohexyl-2biphenylethanes, 1-phenyl-2-cyclohexyl-phenylethanes, optionally halogenated stilbenes, benzyl phenyl ethers, tolanes and substituted cinnamic acids.
The 1,4-phenylene groups of these compounds may be fluorinated.
The most important compounds which are possible constituents of liquid crystal media according to the invention can be characterized by the formulae 1, 2, 3, 4 and 5:
R'-L-U-R" 1
R'-L-COO-U-R" 2 R' -L-OOC-U-R" 3 R' -L-CH2CH2-U-R" 4 R'-L-C-C-U-R" 5
In the formulae 1, 2, 3, 4 and 5 L and U may equal or different from each other.L and U independently from each other denote a bivalent residue selected from the group consisting of -Phe-, -Cyc-, -Phe-Phe-, -Phe-Cyc-, -Cyc-Cyc-, -Pyr-, -Dio-, -G-Phe-, -G-Cyc- and their mirror images; in this compilation of residues Phe denotes unsubstituted or fluorinated 1,4-phenylen, Cyc trans-1,4-cyclohexylene or 1,4-cyclohexenylen, Pyr pyrimidine-2,5-diyl or pyridine-2,5-diyl, Dio 1,3-dioxane-2,4-diyl and G 2-(trans-1,4-cyclohexyl)-ethyl, pyrimidine-2,5-diyl, pyridine-2,5-diyl or 1,3-dioxane-2,5diyl.
One of the residues L and U is preferably Cyc, Phe or Pyr. U preferably denotes Cyc, Phe or Phe-Cyc. The liquid crystal media according to the invention preferably contain one or more components selected from the compounds of formulae 1, 2, 3, 4 and 5 with L and U meaning Cyc, Phe and Pyr, said liquid crystal media further containing at the same time one or more components selected from the compounds of formulae 1, 2, 3, 4 and 5 with one of the residues L and U denoting Cyc, Phe and
Pyr and the other residue being selected from the group consisting of -Phe-Phe-, -Phe-Cyc-, -Cyc-Cyc-, -G-Cyc-, said liquid crystal media containing in addition to this optionally one or more components selected from the compounds of formulae 1, 2, 3, 4 and 5 with L and U being selected from the group consisting of -Phe-Cyc-, -Cyc-Cyc-, -G-Phe- and
G-Cyc.
In a preferred subgroup of the compounds of formulae 1, 2, 3, 4 and 5 (subgroup 1) R' and R" are independently from each other alkyl, alkenyl, alkoxy, alkenoxy with up to 8 carbon atoms. R' and R" differ from one another in most of these compounds, one of the residues usually being alkyl or alkenyl. In another preferred subgroup of the compounds of formulae 1, 2, 3, 4 and 5 (subgroup 2) R" denotes -CN, -CF3, -OCF3, -OCHF2, -F, -C1 or -NCS while R' has the meaning indicated in subgroup 1 and is preferably alkyl or alkenyl. Other variants of the envisaged substituents in the compounds of formulae 1, 2, 3, 4 and 5 are also customary. Many such substances are commercially available. All these substances are obtainable by methods which are known from the literature or by analogous methods.
The liquid crystal media according to the invention preferably contain in addition to components selected from subgroup 1 also components of subgroup 2, the percentage of these components being as follows: subgroup 1: 20 to 90 %, in particular 30 to 90 % subgroup 2: 10 to 50 %, in particular 10 to 50 %
In these liquid crystal media the percentages of the compounds according to the invention and the compounds of subgroup 1 and 2 may add up to give 100 %.
The media according to the invention preferably contain 1 to 40 %, in particular 5 to 30 % of the compounds according to the invention. Media containing more than 40 %, in particular 45 to 90 % of the compounds according to the invention are further preferred. The media contain preferably 3, 4 or 5 compounds according to the invention.
The media according to the invention is prepared in a manner which is customary per se. As a rule, the components are dissolved in one another, advantageously at elevated temperature. The liquid crystal media according to the invention can be modified by suitable additives so that they can be used in all the types of liquid crystal display devices. Such additives are known to the expert and are described in detail in the literature (H. Kelker/R. Hatz, Handbook of Liquid
Crystals, Verlag Chemie, Weinheim, 1980). For example, it is possible to add pleochroic dyestuffs to prepare colored guest-host systems or substances for modifying the dielectric anisotropy, the viscosity and/or the orientation of the nematic phases.
The following examples are to be ccnstrued as merely illustrative and not limitative. m.p. = melting point, c.p. = clearing point. In the foregoing and in the following all parts and percentages are by weight and the temperatures are set forth in degrees Celsius. "Customary work-up" means that water is added, the mixture is extracted with methylene chloride, the organic phase is separated off, dried and evaporated, and the product is purified by crystallization and/or chromatography.
Further are:
C: crystalline-solid state, S: smectic phase (the index denoting the type of smectic phase), N: nematic phase, Ch: cholesteric phase, I: isotropic phase. The number being embraced by 2 of these symbols denotes the temperature of phase change.
Example 1
a) 4-Bromophenvlslvoxal monohvdrate
Silver nitrate (0.05 mol) was added to a solution of
4-bromo-phenacyl bromide (0.041 mol) in acetonitrile (80
ml). After stirring for 24 hours at room temperature the
green precipitate was filtered off and washed with ether.
The washings and filtrate were combined and the solvent
removed under reduced pressure (30 mm, 30 OC) to leave an
oily residue. This was dissolved in ether, washed with
water, dried and the solvent removed to yield a crude
nitrate ester which was converted to 4-bromophenylglyoxal
without further purification by the following method:
Sodium acetate trihydrate (0.004 mol) was added to the
crude nitrate ester (9.2 g) dissolved in dimethylsul
phoxide (150 ml) and stirred for 30 min. at 20-25 OC. The
reaction mixture was poured onto ice, the resulting
solution was saturated with sodium chloride and was then
extracted with ether.The combined organic extracts were
washed with water, aqueous sodium bicarbonate, dried, the
solvent removed and the crude glyoxal recrystallised from
acetone/water to give 4-bromophenylglyoxal monohydrate,
mp. 127-8 OC.
b) 5-(4-Bromoshenvl)-2-Dvrazinol) 4-Bromophenylglyoxal monohydrate (0.065 mol) was dis
solved in methanol, cooled to below -40 OC and dry pow
dered glycinamide hydrochloride (0.065 mol) added to the
stirred solution. The temperature was allowed to rise to
-30 OC and maintained at this temperature while sodium
hydroxide (0.15 mol) in 25 ml water was added dropwise
over 5 minutes. The reaction mixture was maintained at
this temperature overnight and then allowed to rise to
room temperature over 4 hours. After cooling to 0 OC the
pH was adjusted to 5.0 with concentrated hydrochloric
acid when an oranse/brown precipitate of 5-(4-bromo
phenyl)-2-pyrazinol formed which was collected and washed
with water.Purification was carried out by dissolving
the crude product in 2M sodium hydroxide and washing with
dichlormethane. The product was reprecipitated using
concentrated hydrochloric acid, filtered and washed with
water to pH 7.0. [mp. 226-8 C (decomposition); m/z
250 (M+) The 5-(4-Bromophenyl)-2-pyrazinol appears to exist mainly
in the keto form.
c) 5-(4-Bromophenyl)-2-n-pentoxypyrazine 5- (4-Bromophenyl) -2-pyrazinol (0.018 mol) and anhydrous
potassium carbonate (0.045 mol) were added to dimethyl
formamide. The mixture was stirred and 1-n-bromopentane
(0.029 mol) was added and refluxed for 15 min. The cooled
reaction mixture was poured into water and the products
extracted into ethyl acetate which was removed under
reduced pressure to yield a brown oil. The reaction
products were purified by column chromatography on silica
gel, eluting initially with petroleum ether (60-80 OC), and finally with 50:50 petroleum ether, ethyl acetate.
The 5-(4-bromophenyl)-2-n-pentoxypyrazine was further
purified by recrystallisation from methanol to give a
white crystalline solid.
d) 4-n-Propvlphenylboronic acid
4-n-Propylbromobenzene (0.04 mcl) was dissolved in dried
THF (100 ml) and placed in a dropping funnel. This solu tion was added slowly to magnesium (0.044 mol) under an
atmosphere of nitrogen. Initiation of the reaction was
carried out using heat and an iodine crystal. The reac
tion mixture was then refluxed for 1 hour until no magne
sium remained and then was cooled to 0 C in ice. Trimethyl
borate (0.06 mol) was slowly added to give a creamy
precipitate which was stirred overnight. Hydrolysis with
dilute hydrochloric acid (20 %) caused all of the solid
to dissolve and the product was then extracted into
ether. Combination of the extracts, drying, and removal
of the ether gave the desired product.
e) 2-n-Pentoxy-5-[4-(4-n-propylphenyl) phenyl]pyrazine
Into a flask was placed 5-(4-bromophenyl)-2-n-pentoxy
pyrazine (0.0016 mol), tetrakis(triphenylphosphine)palla
dium (0.1 mol %), toluene (8 volumes), and aqeous sodium
carbonate (4 volumes of a 2M solution). To this stirred
solution was added 4-n-propylphenylboronic acid
(0.0016 mol) which was dissolved in the minimum quantity
of hot ethanol. The reaction was refluxed under nitrogen
until complete (TLC). After dilution with water, the
product was extracted with dichloromethane, the organic
layer was washed with water, then dried. The solvent was
removed and the product purified by flash chromatography
on silica gel. C 92.4 SE 143.0 S3 156.5 SA 191.2 N 192.5 I
The following compounds of the formula
are prepared analogously.
R1 X R2 (F)x n-C3H7 OC6H13 C 92.6 SE 135.9 Sg 149.8 SA 191.4 N 192.1 I n-C3H7 OC7H15 C 77.3 SE 132.7 SB 147.8 SA 187.9 I n-C3H7 OCBH17 C 86.8 SE 130.5 SB 149.9 SA 198.5 n-C4Hs -c OC5Hll n-C4H9 -c OC6H13 n-C4H9 -c < OC7H15 n-C4H9 -c OCBH17 n-C5H11 X OC6H13 n-CsHll -c OC7H15 n-C5H11 -c OC8H::7
R1 ~03 R2 (F)x F n-C3H7 - OC6Hi3 F n-C5H1i A OC8Ho7 n-CsHll > OC8H17 n-C3H7 C- F n-C3H7 @ - Cl n-C5Hll e F n-C5Hii -Th Cl n-C5Hi i e CF3 n-C5Hi i C- OCF3 n-C3H7 {Dn-C3H C- OC4H9 C 91.72 SE 149.2 Sg 161.0 SA 198.7 N 201.3 I n-C3H C- OC9Hi9 C 91.8 SE 120.7 SB 138.3 N 180.5 I
R1 \D R2 (F)x n-C3H7 ~\ X ~ OCloH21 C 93.2 SE 118.0 5B 135.0 N 181.0 I n C3H7 OC12H25 C 105.4 SE 108.0 SB 128.4 N 171.7 I F -C- OC4H9 C 118.7 SA 202.3 I F -D OC5Hii C 120.0 SA 204.0 I F -D OC6H13 C 110.5 SA 195.5 I F C- OC7H15 C 117.1 SA 191.1 I F C- OC8H17 C 115.6 SA 188.0 I F -D OC9H19 C 116.2 SA 179.4 I F C- OC10H21 C 117.1 SA 178.6 I F - X - OC12H25 C 121.3 SA 170.5 I Example 2
a) 2, 3-Diflurobutoxvbenzene 1-Bromobutane (0.184 mol) was added to a mixture of
butanone (100 cm3), potassium carbonate (0.345 mol) and
2,3-difluorophenole (0.115 mol). The mixture was refluxed
for six hours after which it was allowed to cool and the
salts were filtered off and washed with butanone. The
washings were combined with the filtrate and the solvent
removed under pressure to have a yellow liquid which was
destilled at 110-112 OC/1.8 mm Hg.
IR (liquid film): 2850-2980 (C-H alkene), 1660, 1500
(C=C aromatic), 1480 (CH2 bend), 1320 (CH3 bend), 1080 (C-O).
b) 2,3-Difluoro-4-butoxv phenylene boronic acid
33,75 cm3 Butyl-lithium (1.6 mol in hexane) was added
dropwise to a stirred cooled solution (-70 OC) of 2,3
difluorobutoxybenzene (0.054 mol) in 90 cm3 dry THF under
dry nitrogen. The reaction mixture was maintained under
these conditions for 2.5 hours and then a previously
cooled solution of tri-isopropylborate (0.108 mol) in dry
THF (60 cm3) was added dropwise at -78 OC. The reaction
mixture was allowed to warm to room temperature overnight
and then stirred for 1 hour with 10 % hydrochloric acid
(100 cm3). The product was extracted into ether, the ether
extracts were combined and the product was extracted into
1 N NaOH solution which was washed with ether and then
acidified to neutrality.The product was then reextracted
back into ether. The solvent was removed under pressure
to have a beige solid which was washed with petrol ether (60-800) to give a white solid of 2,3-difluoro-4-butoxy
phenylboronic acid.
c) 2- (2 13-difluoro-4-butoxvbihenvl-5-entoxv-vrazine A solution of 4-butoxy-2,3-difluoro-phenylboronic acid
[0.0097 mol] in ethanol was added to a stirred mixture of
5-(4-bromo-phenyl)-2-(pentoxy)pyrazine (0.0031 mol), tetrakis- (triphenylphosphine) palladium(0) (0.00016 mol),
dimethoxyethane and aqueous sodium carbonate (40 cm3 of
2 M solution). The resultant mixture was refluxed under
nitrogen until the reaction was complete (TLC). Upon
cooling the product was extracted into dichloromethane,
washed with 1N NaOH solution, water and dried. The sol
vent was removed under reduced pressure and the resultant
solid was columned on silca gel using petrol ether (60-800) .
IR (KBr): 2900 (C-H aromatic stretch), 1640, 1500 (C=C
aromatic), 1480 (CH2 bend), 1355 (CH3 bend), 1300, 1200,
1080 cm-1
The following compounds of the formula
are prepared analogously.
R R
H9C40 OC5Hll C 103.1 S 140.4 N 168.3 I
H9C40 OC6Hl3 C 88.4 S 139.0 N 166.0 I
H9C4O OC7H15 C 97.5 S 139.2 N 154.3 I
H9C4O OC8H17 C 93.1 S 142.1 N 160.7 I
H9C4O OC9H1 C 98.0 S 143.5 N 158.3 I
H9C4O OCloH2l C 89.7 S 137.0 N 150.1 I
H11C5O OC6H13
H11C5O OC7H15
H11C5O OC8H17
H11C5O OC9H19
H11C5O OC10H21
H13C6O OC6H13
H13C6O OC7H15
H13C6O OC8H17
H13C6O OC10H21 R1 R2
H11C5 OC6H13
H11C5 OC7H15
H11C5 OC8H17
H11C5 OC9H19
H11C5 OC10H21
Example 4
0.1 mol 5-(4-Bromophenyl)-2-n-pentoxypyrazine (example 1c) is coupled with 0.1 mol n-propyl-cyclohexylbromide according to scheme 1.
The following compounds of the formula
are prepared analogously:
R1 X R2 (F)x n-C3H7 OC6H13 n-C3H7 \ n-C3H7 OC7H25 n-C3H C- OC8H17 n-C5Hii C- OC6H13 n-C5Hll C- OC7Hl5 n-C5Hll C- OC8H17 m OCloH n-C5H1i OC10H21 n-C5Hll X OC12H25 n-C3H C- Cl n-C5Hll C1 Cl n-C3H C- F n-C5H1 i t F
Claims (11)
- Clams 1. Phenylpyrazines of the formula I,wherein Ri and R2 are an alkyl group of 1-15 C atoms, wherein one or two non-adjacent CH2 groups can also be replaced by 0 atoms and/or -CO- groups and/or -O-CO-groups and/ or -CO-O- groups and/or -O-COO groups and/or -CH-halogen groups, and one of Ri or R2 may be Q-Y, wherein Y is H, F or Cl, and Q is -CF2-, -CF2CF2-, -OCF2-, -OCF2CF2- or a single bond.is a a trans-1,4-cyclohexylene group or a 1,4-phenylene group which is unsubstituted or monosubstituted or polysubstituted by F and/or Cl atoms, and x 0, 1 or 2, and also to liquid crystalline media being a mixture of at least 2 compounds, characterized in that at least one compound is a phenylpyrazine according to formula I.
- 2. Phenylpyrazines of the formula Ie,wherein x is 0, 1 or 2, and
- 3. Phenylpyrazines of the formula If,wherein x is 0, 1 or 2, and Hal is F or C1.
- 4. Phenylpyrazines of the formula Id,wherein R2 and x have the meaning given in Claim 1.
- 5. Phenylpyrazines of the formula Ig,wherein Ri and x have the meaning given in claim 1, L1 and L2 are each independently H or F, and Hal is F or Cl.
- 6. Phenylpyrazines of the formula Ih,wherein R2 has the meaning given in claim 1 and Hal is F or C1.
- 7. Phenylpyrazines of the formula Ii,wherein R1 and R2 have the meaning given in claim 1.
- 8. Use of the compounds of the formula I according to Claim 1 as components of liquid-crystalline media.
- 9. Liquid-crystalline medium containing at least two liquid crystalline components, characterized in that at least one component is a compound of the formula I.
- 10. Liquid crystal display element, characterized in that it contains a medium according to Claim 9.
- 11. Electro-optical display element according to Claim 10, characterized in that it contains as dielectric a medium according to Claim 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9221139A GB2271351A (en) | 1992-10-08 | 1992-10-08 | Carbocyclyl-phenyl-pyrazines and liquid crystalline media |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9221139A GB2271351A (en) | 1992-10-08 | 1992-10-08 | Carbocyclyl-phenyl-pyrazines and liquid crystalline media |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9221139D0 GB9221139D0 (en) | 1992-11-25 |
| GB2271351A true GB2271351A (en) | 1994-04-13 |
Family
ID=10723135
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9221139A Withdrawn GB2271351A (en) | 1992-10-08 | 1992-10-08 | Carbocyclyl-phenyl-pyrazines and liquid crystalline media |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2271351A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7964220B2 (en) | 2002-02-04 | 2011-06-21 | ALFAMA—Investigação e Desenvolvimento de Produtos Farmacêuticos, Lda. | Method for treating a mammal by administration of a compound having the ability to release CO |
| US7968605B2 (en) | 2002-02-04 | 2011-06-28 | ALFAMA—Investigação e Desenvolvimento de Produtos Farmacêuticos, Lda. | Methods for treating inflammatory disease by administering aldehydes and derivatives thereof |
| US8389572B2 (en) | 2006-01-24 | 2013-03-05 | Hemocorm Limited | Therapeutic delivery of carbon monoxide |
| US9611286B2 (en) | 2011-07-21 | 2017-04-04 | Alfama, Inc. | Ruthenium carbon monoxide releasing molecules and uses thereof |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63135346A (en) * | 1986-11-28 | 1988-06-07 | Canon Inc | Optically active compound and liquid crystal composition and ferroelectric liquid crystal element containing said compound |
-
1992
- 1992-10-08 GB GB9221139A patent/GB2271351A/en not_active Withdrawn
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63135346A (en) * | 1986-11-28 | 1988-06-07 | Canon Inc | Optically active compound and liquid crystal composition and ferroelectric liquid crystal element containing said compound |
Non-Patent Citations (1)
| Title |
|---|
| Chemical Abstracts, Vol.110(6), abstract no. 49052x & JP 63/135346 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7964220B2 (en) | 2002-02-04 | 2011-06-21 | ALFAMA—Investigação e Desenvolvimento de Produtos Farmacêuticos, Lda. | Method for treating a mammal by administration of a compound having the ability to release CO |
| US7968605B2 (en) | 2002-02-04 | 2011-06-28 | ALFAMA—Investigação e Desenvolvimento de Produtos Farmacêuticos, Lda. | Methods for treating inflammatory disease by administering aldehydes and derivatives thereof |
| US9023402B2 (en) | 2002-02-04 | 2015-05-05 | ALFAMA—Investigação e Desenvolvimento de Produtos Farmacêuticos, Lda. | Method for treating a mammal by administration of a compound having the ability to release CO |
| US8389572B2 (en) | 2006-01-24 | 2013-03-05 | Hemocorm Limited | Therapeutic delivery of carbon monoxide |
| US9611286B2 (en) | 2011-07-21 | 2017-04-04 | Alfama, Inc. | Ruthenium carbon monoxide releasing molecules and uses thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9221139D0 (en) | 1992-11-25 |
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