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WO1986000067A1 - Pyrimidines - Google Patents

Pyrimidines Download PDF

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Publication number
WO1986000067A1
WO1986000067A1 PCT/GB1985/000266 GB8500266W WO8600067A1 WO 1986000067 A1 WO1986000067 A1 WO 1986000067A1 GB 8500266 W GB8500266 W GB 8500266W WO 8600067 A1 WO8600067 A1 WO 8600067A1
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WO
WIPO (PCT)
Prior art keywords
alkyl
alkoxy
group
pyrimidine
formula
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/GB1985/000266
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English (en)
Inventor
George William Gray
David Lacey
Kenneth Johnson Toyne
Richard Michael Scrowston
Adam Jackson
Edward Peter Raynes
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UK Secretary of State for Defence
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UK Secretary of State for Defence
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Priority to GB08602796A priority Critical patent/GB2171696B/en
Publication of WO1986000067A1 publication Critical patent/WO1986000067A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D239/00—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings
    • C07D239/02—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings not condensed with other rings
    • C07D239/24—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings not condensed with other rings having three or more double bonds between ring members or between ring members and non-ring members
    • C07D239/28—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings not condensed with other rings having three or more 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, directly attached to ring carbon atoms
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D239/00—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings
    • C07D239/02—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings not condensed with other rings
    • C07D239/24—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings not condensed with other rings having three or more double bonds between ring members or between ring members and non-ring members
    • C07D239/28—Heterocyclic compounds containing 1,3-diazine or hydrogenated 1,3-diazine rings not condensed with other rings having three or more 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, directly attached to ring carbon atoms
    • C07D239/32—One oxygen, sulfur or nitrogen atom
    • C07D239/34—One oxygen atom
    • 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
    • C09K19/3458—Uncondensed pyrimidines
    • 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
    • C09K19/3458—Uncondensed pyrimidines
    • C09K19/3469—Pyrimidine with a specific end-group other than alkyl, alkoxy or -C*-
    • 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
    • C09K19/42—Mixtures of liquid crystal compounds covered by two or more of the preceding groups C09K19/06 - C09K19/40

Definitions

  • the present invention relates to pyrimidines suitable for use in liquid crystal materials.
  • liquid crystal materials to exhibit electrooptical effects in display devices such as digital calculators, watches, meters and simple word displays.
  • liquid crystal materials are not ideal in all respects and a considerable amount of work is currently being carried out in the art to improve their properties.
  • Liquid crystal materials normally consist of mixtures of compounds and new materials may be obtained by forming new compounds for use in such mixtures.
  • a pyrimidine ester having a formula:
  • R 1 represents a group R 1a or R 1b wherein R 1a is selected from alkyl, alkoxy, alkoxy substituted alkyl, alkanoyl, alkanoyloxy, alkoxycarbonyl and alkoxycarbonyloxy; and R 1b is selected from hydrogen, cyano, fluoro, bromo, chloro and CF 3 ;
  • A represents a group A 1 (E 1 ) m , wherein A 1 is selected from
  • Ph, Ch, Bco and Dx E 1 is selected from -CO.O-, -O.OG-, -CH 2 O-, -OCH 2 and -CH 2 .CH 2 -; and m is 0 or 1;
  • B represents a 2,5 disubstituted 1,3 pyrimidine ring carrying the substituent Z in either its 2 or 5 position;
  • Z represents a group selected from O.OCW 1 and CO.OW 2 wherein each of W 1 and W 2 is independently selected from the following groups:
  • the compounds of Formula I are useful components of liquid crystal materials, eg for electro-optical displays.
  • the group R 1 and/or R 2 contains an n-alkyl group the compounds are, generally speaking, nematogenic and are useful as components of nematic liquid crystal materials.
  • R 1 and/or R 2 contains a chiral alkyl group, eg (+)-2-methylbutyl, the compounds are, generally speaking, chiral nematogenic.
  • Chiral nematogenic compounds (alternatively known as cholesterogenics) may be used as chiral additives to nematic materials or in other applications, eg temperature sensing applications taking advantage of their selective reflection of radiation. The principal reflected Wavelengths can be varied as a function of temperature.
  • a preferred species of compounds of Formula I are those wherein R 1 represents alkyl or alkoxy n is zero and -B- represents ** "" ⁇ _2 ⁇ ' .
  • R A -Py-CO.O-Ph.Ph-R B lb wherein R A represents alkyl or alkoxy, Py represents — ⁇ 0-" and Ph represents ⁇ j y or v and R B represents alkyl, alkoxy or cyano.
  • each alkyl group included in the terminal group(s) R 1 and/or R 2 is preferably a group having from 1 to 12 carbon atoms. It is preferably an n-alkyl group although it may alternatively be a chiral group eg (+)-2-methylbutyl. Where the group R 1 and/or R 2 includes an alkyl group it preferably has from 1 to 12 carbon atoms.
  • Figure 1 to 4 are schematic flow diagrams of preliminary routes which may be used for the preparation of intermediates.
  • Figures 5 and 6 are schematic flow diagrams of routes which may be used for the preparation of compounds of various sub-classes of formula I;
  • Figures 7 to 13 are diagrams illustrating the construction and operation of an electro-optical device embodying the invention. These Figures are described further below.
  • the dielectric anisotropy of a liquid crystal compound or mixture is an important parameter which determines the operation voltage of an electro-optical cell incorporating the compound or mixture. It also determines, together with the cell may be used. Examples of known effects are described below.
  • the compounds of Formula I may have a strongly positive, strongly negative or small dielectric anisotropy depending on any terminal and/or lateral substituent groups contained within the Formula I structure.
  • the compounds of Formula I may be added to liquid crystal materials of positive or negative dielectric anisotropy, known and referred to herein respectively as "positive” or “negative” materials in order to produce a mixture having amongst other things a suitable dielectric anisotropy and suitable liquid crystal transition temperatures.
  • one or more compounds of Formula I are mixed with one or more compounds of high positive dielectric anisotropy ⁇ , ie then compounds of reasonably low melting point are preferred for use as the high dielectric anisotropy components to which the formula I compounds are added.
  • compounds of the classes whose generalised formulae are listed in Table.1 are suitable as positive materials.
  • each R is independently n-alkyl or n-alkoxy and each R A is independently n-alkyl.
  • the compounds of Formula I may be added to small dielectric anisotropy compounds, which may also be low melting, ie having a melting point less than
  • one or more compounds of Formula I may be added to one or more compounds of Formula Ila to Ili listed in Table 1 optionally together with one or more compounds of Formula IlIa to Illn listed in Table 2.
  • Additional high clearing point (clearing point 100°C) compounds may be included in such mixtures, eg one or more compounds selected from the known classes whose generalised formulae are listed in Table 3.
  • liquid crystal material obtained by blending together compounds of Formula I with those of the other classes as specified may be any one of the following:
  • a negative material preferably also with a pleochroic dye, for use in Freedericksz effect devices (negative nematic type) in which the molecular arangement may be changed from the homeotropic texture (OFF state) to the homogenous texture (ON state) by an electric field; an example of such a device is given below;
  • a positive nematic material preferably also with a pleochroic dye, for use in Freedericksz effect devices (positive nematic type in which the molecular arrangement may be changed from the homogeneous texture (OFF state) to the homeotropic texture (ON state) by an electric field;
  • a negative material which is a cholesteric (chiral nematic) of suitable resistivity (about 10 9 ohm-cm), for use in cholesteric memory mode devices in which the molecular arrangement may be changed from a homogeneous texture (OFF state) to a scattering focal conic texture (ON state) by an electric field;
  • a strongly negative material which is a cholesteric, preferably together also with a pleochroic dye, for use in cholesteric-to-nematic phase change effect devices (positive contrast type) in which the molecular arrangement may be changed from a weakly scattering, ie clear, surface aligned hometropic texture (OFF state) to a strongly scattering twisted homeogenous texture (ON state) by an electric field
  • a positive material which is a cholesteric, preferably together also with a pleochroic dye, in cholestericto-nematic phase change effect devices (negative contrast type) in which the molecular arrangement may be changed from a scattering focal conic texture (OFF state) to a clear homeotropic texture (ON state) by an electric field
  • negative contrast type in which the molecular arrangement may be changed from a scattering focal conic texture (OFF state) to a clear homeotropic texture (ON state) by an electric field
  • a negative nematic material of suitable resistivity (about 10 9 ohm-cm), in dynamic scattering effect devices in which the molecular arrangement may be changed from a clear homeotropic texture (OFF state) to a turbulent scattering texture (ON state) by an electric field;
  • a nematic material in two frequency switching effect devices (which may be twisted nematic effect devices) in which the dielectric anisotropy of the material may be changed from (at low frequency) positive (OFF state) to negative (ON state) by the application of a high frequency electric field;
  • a material suitable for the device described in copending UK Patent Application No 8317355 (ix) a material suitable for the device described in copending UK Patent Application No 8317355.
  • liquid crystal material is for use in a twisted nematic effect, cholesteric to nematic phase change effect (negative contrast type) or Freedericksz effect (positive nematic type) device
  • the material preferably contains: Component A: one or more compounds of Formula I plus
  • Component B one or more compounds of Formula Ila to IIi optionally together with one or more of the following: Component C: one or more compounds of Formula IlIa to IIIn; Component D: one or more compounds of Formula IVa to IVl; Component E: one or more chiral additives.
  • Component A 5 to 95% by weight (typically 5 to 75% by weight)
  • Component B 5 to 95% by weight (typically 10 to 50% by weight)
  • Component C 0 to 90% by weight (typically 5 to 25% by weight)
  • Component D 0 to 30% by weight (typically 0 to 20% by weight)
  • Component E 0 to 5% by weight (typically 0 to 1% by weight)
  • phase change negative contrast type
  • proportions may be used:
  • Components A to D in the percentages as specified above; Component E: 2 to 20% (typically 4 to 5%) by weight.
  • a pleochroic dye forming from1.5 to 15% of the overall mixture is preferably added to the liquid crystal material. Suitable dyes are described in published UK Patent Application Nos 2081736A, 208219A and
  • each dye compound incorported forms 1 to 3% by weight of the overall mixture.
  • Liquid crystal mixtures including compounds of Formula I may be formed in a known way, eg simply by heating the constituent compounds togeher in the correct weight proportion to form an overall isotropic liquid (eg about 100°C).
  • At least one compound according to Formula I above may be mixed together with one or more compounds in any one or more of the known families listed in Table 4 for use in one or more of the applications given above (the actual applications) depending on the mixture's properties):
  • each X is a 1,4 phenylene group, a 4,4' biphenylyl group, a 2,6 naphthyl group or a trans-1,4- disubstituted cyclohexane ring
  • Y 1 is CN, or R' or halogen or CO.O-X-Y 1 where Y 1 is CN, or R' or OR'; where R and R' are alkyl groups; the compound may alternatively be a derivative of one of those listed in Table 4 wherein H is replaced by a halogen, eg F, in one or more of the benzene rings of the structure.
  • the compound(s) of Formula I comprises between 5 and 95% by weight of the mixture.
  • a liquid crystal device in a second aspect includes two dielectric substrates at least one of which is optically transparent, a layer of liquid crystal material sandwiched between the substrates and electrodes on the inner surfaces of the substrates to enable an electric field to be applied across the layer of liquid crystal material to provide an electro-optic effect therein,
  • liquid crystal material characterised in that the liquid crystal material consists of or includes a compound according to Formula I above.
  • the device according to the second aspect may be a twisted nematic effect device, which may or may not be operated in a multiplexed fashion, a cholesteric-to-nematic phase change effect device, a Freedericksz effect device or a two-frequency switching effect device, all constructed in a known manner or any of the other devices mentioned above.
  • a twisted nematic effect device which may or may not be operated in a multiplexed fashion
  • a cholesteric-to-nematic phase change effect device a Freedericksz effect device or a two-frequency switching effect device, all constructed in a known manner or any of the other devices mentioned above.
  • liquid crystal compounds which are esters are known esters having a -CO.O- group attached directly to a pyrimidine ring have not previously been published.
  • the compounds of Formula I can show certain advantageous-properties. For example, they can show a low ratio k 33 /k 11 where k 33 and k 11 are elastic constants well understood in the art. Such a low ratio provides a basis for good multiplexibility in liquid crystal materials suitable for multiplexed twisted nematic operation.
  • each alkyl or alkoxy group R A or R B in Formula la is n-alkyl or n- alkoxy. Desirably, both R A and R B are n-alkyl.
  • Especially preferred mixtures for multiplexed twisted nematic operation comprise:
  • the ester compounds of Formula I may be produced using procedures which are known per se the overall production route being new.
  • Z CO.OW 2 they may be produced by an esterification reaction of the carboxylic acid R 1 -(A) n -B-COOH, or a derivative thereof eg its chloride, and the appropriatehydroxy compound W 2 OH.
  • Z O.OCW 1 they may be produced from the appropriate hydxoxy compound R 1 -(A) n -OH by esterification with the appropriate carboxylic acid W 1 COOH or a suitable derivative thereof.
  • radicals R 1 (A) n to pyrimidine rings are known and such methods may be employed in the course of the formation of the appropriate esters or their precursors -R 1 (A) n -B-CO.OH and R 1 (A) 1 -B-OH.
  • Step 1a The production of 2-alkyl-3-ethoxyprop-2-enals from the corresponding alkylmalondialdehyde tetraethyl acetals.
  • This Step can be carried out by a standard literature method - as for example described by A BOLLER, M CEREGHETTI, M SCHADT and H SCHERRER, in Mol.Cryst .Liq .Cryst; 42, 215 (1977)
  • Step 1b The production of 5-alkylpyrimidin-l-ylmethanols from the corresponding 2-alkyl-3-ethoxyprop-2-enals.
  • This Step can be carried out by a standard literature method using 2-hydroxyacetamidine hydrochloride prepared from glycollic acid nitrile via the hydrochloride of HOCH 2 .
  • OC 3 H 7 - as for example described by A BOLLER, M CEREGHETTI, M SCHADT and H SCHERRER, in Mol.Cryst.Liq.Cryst; 42, 215 (1977)
  • Step lc The production of 5-alkyl-2-carboxypyrimidines from the corresponding 5-alkylpyrimidin-l-ylmethanoxs.
  • This Step can be carried out by first oxidising the 5- alkylprimidin-l-ylmethanol to the 5-alkylprimidine-2- carboxyaldehyde. This is achieved using toluene as solvent and manganese dioxide as the oxidising agent according to the method described by A BOLLER, M CEREGHETTI, M SCHADT and M SCHERRER, in Mol.Cryst.Liq.Cryst; 42, 215 (1977).
  • the aldehyde is isolated, but not purified before it is converted by mild oxidation - for example by known literature methods using dilute nitric acid - into the 5-alkyl-2-carboxypyrimidine which is readily purified by crystallisation from ethanol.
  • This Step can be carried out using a standard literature method for the production of dihydroxypyrimidines from amidinehydrochlorides - in this case acetamidine hydrochloride - as for example described in East German Patent, 95892.
  • Step 2b The production of 5-alkoxy-4,6-dichloro-2-methyl- pyrimidines from the corresponding 5-alkoxy-4,6-dihydroxy-2- methylpyrimidines.
  • Step 2c The production of 5-alkoxy-4,6-dichloro-2- tribromomethylpyrimidines from the corresponding 5-alkoxy-4,6- dichloro-2-methylpyrimidines.
  • Step 2d The production of 5-alkoxy-2-carboxy- 4,6-dichloropyrimidines from the corresponding 5-alkoxy-4,6- dichloro-2-tribromomethyl-pyrimidines.
  • This Step can be carried out by hydrolysis procedures of a standard nature or by treatment with silver nitrate in acetic acid - as for example described in USSR Patent 104411 (1956) - [Chem.Abstr; 51, 6709 (1957)]
  • Step 2e The production of 5-alko y-2-carboxypyrimidines from the corresponding 5-alkoxy-2-carboxy-4,6- dichloropyrimidines.
  • This Step can be carried out by a standard literature procedure for the catalytic dechlorination of dichloropyrimidines - as for example described in East German Patent 95892. ROUTE 3
  • Step 3a The production of 5-alkyl-2-hydroxypyrimidines from the corresponding 2-alkyl-3-ethoxyprop-2-enals.
  • This Step can be carried out using the method of A BOLLER, M CEREGHETTI, M SCHADT and M SHERRER for the production of pyrimidines from ethoxyacroleins, but replacing the 2-hydroxyacetamidine hydrochloride by urea - as for example described in Mol.Cryst.Liq.Cryst; 42, 215 (1977).
  • the 5- alkyl-2-hydroxypyrimidines are readily purified by crystallisation from common organic solvents such as methanol.
  • Step 4a The production of 5-alkoxy-4, 6-dihydroxy-2- thioethylpyrimidines from the corresponding diethyl alkoxymalonates.
  • This Step can be carried out using a standard literature method for the production of dihydroxypyrimidines from amidine hydrochlorides - as for example described in East German Patent 95892.
  • the amidine hydrochloride used is S- ethylisothiourea hydrochloride (C 2 H 5 S.C.NH 2 .HCl) - see the classical literature procedure of Wheeler and Johnson (1903) for the synthesis ofcytosine.
  • Step 4b The production of 5-alkoxy-4,6-dichloro-2- thioethylpyrimidines from the corresponding 5-alkoxy-4,6- dihydroxy-2-thioethylpyrimidines.
  • This Step can be carried out as described for STEP 2b of Route 2.
  • Step 4c The production of 5-alkoxy-2-thioethylpyrimidines from the corresponding 5-alkoxy-4,6-dichloro-2- thioethylpyrimidines.
  • This step can be carried out as described for STEP-2c of Route 2.
  • Step 4d The production of 5-alkoxy-2-hydroxyprimidines from the corresponding 5-alkoxy-2-thioethylpyrimidines.
  • This Step can be carried out by treatment of the 5- alkoxy-2-thioethylpyrimidines with hydrogen bromide as described in the classical synthesis of cytosine by Wheeler and Johnson (1903).
  • the lactams formed are tautomeric with the required 5-alkoxy-2-hydroxypyrimidines which are readily purified by crystallisation from a range of organic solvents.
  • esters from 5-alkyl- or 5-alkoxy-2- carboxypyrimidines and 4-alkyl- or 4-alkoxy-phenols typically examples of compounds of formula W 1 OH.
  • Step 5a This Step for the production of these esters can be carried out by standard methods for the conversion of carboxylic acids (via their acid chlorides) into esters by interaction with hydroxy compounds.
  • the esters are isolated and purified by column chromatography on silica gel. Fractions of each of the esters (single spot on tic) are combined and crystallised from either ethyl acetate or light petroleum (bp 40-60°C).
  • the pure esters give infra-red spectra consistent with their structures and mass spectrometry gives the correct mass ion in each case.
  • Figure 7 is a sectional view of a twisted nematic digital display
  • Figure 8 is a sectional view of the display shown in Figure 7 ;
  • Figure 9 shows a rear electrode configuration for Figure
  • Figure to shows a front electrode configuration for Figure7 ;
  • Figures 11, 12 and 13 show schematic views of the device of Figures 7 to 9 with typical addressing voltages.
  • the display of Figures 7 to 10 comprise a cell 1, formed of two, front and back, glass slides 2, 3 respectively, spaced about 7 ⁇ m apart by a spacer 4 all held together by an epoxy resin glue.
  • a liquid crystal material 12 fills the gap between the slides 2, 3 and the spacer 4.
  • a front polariser 5 arranged with its axis of polarisation axis horizontal.
  • a reflector 7 is arranged behind the slide 3.
  • a rear polariser 6 or analyser is arranged between the slide 3 and reflector 7.
  • Electrodes 8, 9 of tin oxide typically 100 ⁇ thick are deposited on the inner faces of the slides 2, 3 as a complete layer and etched to the shapes shown in Figures 9, 10 .
  • the display has seven bars per digit 10 plus a decimal point 11 between each digit.
  • the rear electrode structure is formed into three electrodes x 1 , x 2 , x 3 .
  • the front electrode structure is formed into three electrodes per digit and decimal point y 1 , y 2 , y 3 ... as shown in Figure 10. Examination of the six electrodes per digit shows that each of the eight elements can independently have a voltage applied thereto by application of suitable voltages to appropriate x, y electrodes.
  • the slides 2, 3 bearing the electrodes Prior to assembly the slides 2, 3 bearing the electrodes are cleaned then dipped in a solution of 0.2% by weight of poly-vinyl alcohol (PVA) In water. When dry, the slides are rubbed in a single direction with a soft tissue then assembled with the rubbing directions orthogonal to one another and parallel to the optical axis of the respective adjacent polarisers, Ie so that the polarisers are crossed. When the nematic liquid crystal material 12 is introduced between the slides 2, 3 the molecules at the slide surfaces lie along the respective rubbing directions with a progressive twist between the slides.
  • PVA poly-vinyl alcohol
  • the electric voltage V is an ac signal of 3g 100 Hz square wave, and the sign indicates the phase.
  • Material embodying the invention which are suitable for use as the material 12 in the above device is Mixture 1 specified in Table 6 as follows.
  • a small amount of an optically active material may be added to the nematic material to indiuce a preferred twist in the molecules in the liquid crystal layer. This and the use of appropriate slide surface treatment removes the problems of display patchiness as taught in UK Patent Serial Numbers 1,472,247 and 1,478,592.
  • Suitable optically active materials are:
  • C15 about 0.1 - 0.5% by weight and CB15: about 0.01% to 0.05% by weight.
  • pleochroic dye may be added to enhance the diplay contrast, eg 2% by weight of dye Mixture 2 specified in UK Patent Specification No. 2093475A. One polariser is removed in this case.
  • mixtures embodying the second aspect of the invention may be used in a Freedericksz effect cell.
  • a Freedericksz effect cell Such a cell may be constructed by sandwiching the liquid crystal material between glass slides having electrode filmes deposited on their inner surfaces as In the above device.
  • the polarisers are not necessary; the glass slide inner surfaces are treated with a coating of lecithin and the liquid crystal material Is a negative material whose molecules are aligned in the OFF state perpendicular to the slide substrates (homeotropic texture) by the lecithin coating.
  • Application of an appropriate electric field across the material in the ON state re-arranges the molecules parallel to the slide surfaces (homogeneous texture).
  • a pleochroic dye may be incorporated in the liquid crystal material to enhance the contrast between the ON and OFF states.
  • a Freedericksz effect cell made in the above way may incorporate Mixture 2 below, the cell spacing being 10 ⁇ m.
  • Compound may optionally be added to Mixture 2 (up to 3% by weight of Mixture 2) as a negative additive.
  • the colour When a voltage is applied across the cell, the colour changes from a weakly absorbing state to a strongly absorbing state.
  • a (cholesteric-to-nematic) phase change effect device incorporates a material as defined above.
  • a cell is prepared containing a long helical pitch cholesteric material sandwiched between electrode-bearing glass slides as in the twisted nematic cell described above.
  • the polarisers and surface preparations for homogeneous alignment eg treatment of the glass slide surfaces with SiO, are not used in this case. If the glass slides are untreated and the liquid crystal material has a positive dielectric anisotopy ( ⁇ ) the liquid crystal material is in a twisted focal conic molecular texture in the OFF state which scatters light.
  • the effect of an electric field applied between a pair of electrodes on the respective inner surface of the glass slides Is to convert the region of liquid crystal material between the electrodes on the respective inner surface of the glass slides is to convert the region of lquid crystal material between the electrodes into the ON state which is a homeotropic nematic texture which is less scattering than the OFF state.
  • This is a 'negative contrast' type of phase change effect device.
  • the inner glass slide surfaces are treated, eg with a coating of lecithin, to give alignment perpendicular to those surfaces, and the liquid crystal material has ⁇ negative the material in the OFF state is in a homeotropic texture which has little scattering effect on Incident light. If an electric field is applied between a pair of electrodes on the respective inner surfaces of the glass slides the region of liquid crystal material beteen the electrodes is converted to a twisted homogeneous texture which scatters light (the ON- state). This is a 'positive contrast' type of phase change effect device.
  • the contrast between the two states in each case may be enhanced by the addition of a small amount of a suitable pleochroic dye (eg 1% by weight of the dye mixture specified above in the case where ⁇ is positive) to the liquid crystal material.
  • a suitable pleochroic dye eg 1% by weight of the dye mixture specified above in the case where ⁇ is positive
  • a suitable positive dielectric anisotropy material, Mixture 3, embodying the invention for use in a phase change effect (negative contrast type) device is:
  • the preparation of pyrimidine esters according to the present invention will now be described by way of example only, using Routes 2 and 5 illustrated in Fig 2 and Fig 5 of the accompanying drawings.
  • Step B Condensation of the Diethyl Alkylmalonates with Acetamidine
  • Acetamidine hydrochloride 50 mmol was added to a solution of sodium (150 mg-atom) in super-dry ethanol (300 ml), and the precipitated soduim chloride was filtered off.
  • the diethyl alkylmalonate 50 mmol was added to the filtrate, the mixture was stirred for 48 h, and the precipitated pyrimidine -4, 6 dione was filtered off. It was purified by dissolution in aqueous ammonia (d 0.88) and boiling to expel ammonia and crystallise the pyrimidine -4, 6- dione.
  • the precipitated NN'-dicyclohexylurea was filtered off and the organic layer was washed successively with water (3 x 50 ml), aqueous 5% acetic acid solution (3 x 50 ml) and water (3 x 50 ml). Evaporation of the dried solution gave the crude ester, which was purified by column chromatography on alumina.
  • Ethylene Glycol Dimethyl Ether Di-n-Propyl Urther
  • Ethyl Cellosolve Trade Mark

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  • Organic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Liquid Crystal Substances (AREA)

Abstract

Esters de pyrimidine indiqués pour être utilisés comme cristaux liquides. Les esters possèdent un noyau comprenant un anneau de 1,3-pyrimidine relié en position 2- ou 5- par une liaison ester à un anneau dioxane, bicyclo-octyle, cyclohexyle ou phényle éventuellement substitué, ou à un groupe biphénylyle éventuellement substitué. Des substituants préférés de la pyrimidine sont alkyle ou alkoxy. De préférence, la pyrimidine est liée à un groupe phényle, ou biphénylyle, pouvant présenter un substituant fluoro latéral et un groupe terminal alkyle, alkoxy oy cyano. Le groupe alkyle ou alkoxy est de préférence un groupe n-alkyle ou n-alkoxy pourvu de 1 à 12 atomes de carbone. Les esters de pyrimidine ci-décrits peuvent être mélangés à différentes autres substances à base de cristaux liquides, et l'on décrit des mélanges indiqués, ainsi qu'un dispositif électro-optique destiné à être utilisé avec les pyrimidines de l'invention. Sont également décrits un certain nombre de procédés de préparation des esters de pyrimidine.
PCT/GB1985/000266 1984-06-13 1985-06-13 Pyrimidines Ceased WO1986000067A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08602796A GB2171696B (en) 1984-06-13 1985-06-13 Pyrimidines

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8415039 1984-06-13
GB848415039A GB8415039D0 (en) 1984-06-13 1984-06-13 Pyrimidines

Publications (1)

Publication Number Publication Date
WO1986000067A1 true WO1986000067A1 (fr) 1986-01-03

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1985/000266 Ceased WO1986000067A1 (fr) 1984-06-13 1985-06-13 Pyrimidines

Country Status (4)

Country Link
JP (1) JPS61503033A (fr)
DE (1) DE3590260T1 (fr)
GB (2) GB8415039D0 (fr)
WO (1) WO1986000067A1 (fr)

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4698176A (en) * 1984-01-11 1987-10-06 The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland Heterocyclically substituted ethanes and their use in liquid crystal materials and devices
US4713197A (en) * 1984-01-17 1987-12-15 Merck Patent Gesellschaft Mit Beschrankter Haftung Nitrogen-containing heterocyclic compounds
US4721367A (en) * 1985-04-01 1988-01-26 Canon Kabushiki Kaisha Liquid crystal device
US4725688A (en) * 1984-06-07 1988-02-16 Seiko Instruments Inc. Liquid crystal compound
US4752414A (en) * 1984-02-07 1988-06-21 Merck Patent Gesellschaft Mit Beschrankter Haftung Nitrogen-containing heterocyclic compounds
US4755323A (en) * 1983-06-25 1988-07-05 Merck Patent Gesellschaft Mit Beschrankter Haftung Liquid-crystalline dielectrics
US4774020A (en) * 1985-07-04 1988-09-27 Chisso Corporation Pyrimidinyldioxane derivatives
US4776973A (en) * 1985-02-23 1988-10-11 Merck Patent Gesellschaft Mit Beschrankter Haftung Pyrimidine derivatives
US4812258A (en) * 1983-04-27 1989-03-14 Merck Patent Gesellschaft Mit Beschrankter Haftung Fluorine-containing pyrimidine derivatives
US4820839A (en) * 1985-05-24 1989-04-11 Merck Patent Gesellschaft Mit Beschrankter Haftung Nitrogen-containing heterocyclic esters
US4826979A (en) * 1986-06-13 1989-05-02 Alps Electric Co., Ltd. Liquid crystal compound
US4835274A (en) * 1986-06-13 1989-05-30 Alps Electric Co., Ltd. Liquid crystal compound
US4871469A (en) * 1986-05-02 1989-10-03 Bescrankter Haftung Nematic liquid-crystalline phases
US4874546A (en) * 1985-05-15 1989-10-17 Chisso Corporation Phenylpyrimidinecarboxylate derivative
US4876026A (en) * 1986-12-26 1989-10-24 Chisso Corporation Optically active-2-methylbutyrate and materials using the same
US4886622A (en) * 1986-08-18 1989-12-12 Chisso Corporation Optically active liquid crystal compound having cyano group
US4892676A (en) * 1986-09-09 1990-01-09 Ajinomoto Co., Inc. Phenyl pyrimidine compound and liquid crystalline composition
US4913838A (en) * 1987-03-20 1990-04-03 Chisso Corporation Liquid crystal compound with a 4-(optically active alkyl)-3-cyanophenyl group
US5064566A (en) * 1985-04-27 1991-11-12 Merck Patent Gesellschaft Mit Beschrankter Haftung Smectic liquid crystal phases
US5279762A (en) * 1985-04-27 1994-01-18 Merck Patent Gesellschaft Mit Beschrankter Haftung Smectic liquid crystal phases

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1989003867A1 (fr) * 1987-10-19 1989-05-05 Casio Computer Company Limited Melange de cristaux liquides ameliore

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0025119A1 (fr) * 1979-08-20 1981-03-18 VEB Werk Für Fernsehelektronik im VEB Kombinat Mikroelektronik Cristaux liquides nématiques de 5-alkyl-2-(4-acyloxyphényl)-pyrimidines destinés à des dispositifs opto-électroniques et procédé pour leur préparation
EP0056501A2 (fr) * 1981-01-19 1982-07-28 MERCK PATENT GmbH Mélange de cristaux liquides

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0025119A1 (fr) * 1979-08-20 1981-03-18 VEB Werk Für Fernsehelektronik im VEB Kombinat Mikroelektronik Cristaux liquides nématiques de 5-alkyl-2-(4-acyloxyphényl)-pyrimidines destinés à des dispositifs opto-électroniques et procédé pour leur préparation
EP0056501A2 (fr) * 1981-01-19 1982-07-28 MERCK PATENT GmbH Mélange de cristaux liquides

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4812258A (en) * 1983-04-27 1989-03-14 Merck Patent Gesellschaft Mit Beschrankter Haftung Fluorine-containing pyrimidine derivatives
US4755323A (en) * 1983-06-25 1988-07-05 Merck Patent Gesellschaft Mit Beschrankter Haftung Liquid-crystalline dielectrics
US4698176A (en) * 1984-01-11 1987-10-06 The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland Heterocyclically substituted ethanes and their use in liquid crystal materials and devices
US4713197A (en) * 1984-01-17 1987-12-15 Merck Patent Gesellschaft Mit Beschrankter Haftung Nitrogen-containing heterocyclic compounds
US4882082A (en) * 1984-02-07 1989-11-21 Merck Patent Gesellschaft Mit Beschrankter Haftung Nitrogen-containing hetercyclic compounds
US4752414A (en) * 1984-02-07 1988-06-21 Merck Patent Gesellschaft Mit Beschrankter Haftung Nitrogen-containing heterocyclic compounds
US4725688A (en) * 1984-06-07 1988-02-16 Seiko Instruments Inc. Liquid crystal compound
US4776973A (en) * 1985-02-23 1988-10-11 Merck Patent Gesellschaft Mit Beschrankter Haftung Pyrimidine derivatives
US4721367A (en) * 1985-04-01 1988-01-26 Canon Kabushiki Kaisha Liquid crystal device
US5279762A (en) * 1985-04-27 1994-01-18 Merck Patent Gesellschaft Mit Beschrankter Haftung Smectic liquid crystal phases
US5064566A (en) * 1985-04-27 1991-11-12 Merck Patent Gesellschaft Mit Beschrankter Haftung Smectic liquid crystal phases
US4874546A (en) * 1985-05-15 1989-10-17 Chisso Corporation Phenylpyrimidinecarboxylate derivative
US4820839A (en) * 1985-05-24 1989-04-11 Merck Patent Gesellschaft Mit Beschrankter Haftung Nitrogen-containing heterocyclic esters
US5055221A (en) * 1985-05-24 1991-10-08 Merck Patent Gesellschaft Mit Beschrankter Haftung Smectic liquid-crystalline phases
US4774020A (en) * 1985-07-04 1988-09-27 Chisso Corporation Pyrimidinyldioxane derivatives
US4871469A (en) * 1986-05-02 1989-10-03 Bescrankter Haftung Nematic liquid-crystalline phases
US4835274A (en) * 1986-06-13 1989-05-30 Alps Electric Co., Ltd. Liquid crystal compound
US4826979A (en) * 1986-06-13 1989-05-02 Alps Electric Co., Ltd. Liquid crystal compound
US4886622A (en) * 1986-08-18 1989-12-12 Chisso Corporation Optically active liquid crystal compound having cyano group
US4892676A (en) * 1986-09-09 1990-01-09 Ajinomoto Co., Inc. Phenyl pyrimidine compound and liquid crystalline composition
US4876026A (en) * 1986-12-26 1989-10-24 Chisso Corporation Optically active-2-methylbutyrate and materials using the same
US4913838A (en) * 1987-03-20 1990-04-03 Chisso Corporation Liquid crystal compound with a 4-(optically active alkyl)-3-cyanophenyl group

Also Published As

Publication number Publication date
GB8415039D0 (en) 1984-07-18
GB2171696A (en) 1986-09-03
GB2171696B (en) 1988-04-13
GB8602796D0 (en) 1986-03-12
JPS61503033A (ja) 1986-12-25
DE3590260T1 (de) 1986-08-07

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