Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D213/00—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
  • C07D213/02—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
  • C07D213/04—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
  • C07D213/06—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom containing only hydrogen and carbon atoms in addition to the ring nitrogen atom
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D213/00—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
  • C07D213/02—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
  • C07D213/04—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
  • C07D213/60—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom 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
  • C07D213/62—Oxygen or sulfur atoms
  • C07D213/63—One oxygen atom
  • C07D213/64—One oxygen atom attached in position 2 or 6
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D213/00—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
  • C07D213/02—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
  • C07D213/04—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
  • C07D213/60—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom 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
  • C07D213/62—Oxygen or sulfur atoms
  • C07D213/63—One oxygen atom
  • C07D213/65—One oxygen atom attached in position 3 or 5
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D213/00—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
  • C07D213/02—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
  • C07D213/04—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
  • C07D213/60—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom 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
  • C07D213/62—Oxygen or sulfur atoms
  • C07D213/70—Sulfur atoms
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D213/00—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
  • C07D213/02—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
  • C07D213/04—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
  • C07D213/60—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom 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
  • C07D213/78—Carbon atoms having three bonds to hetero atoms, with at the most one bond to halogen, e.g. ester or nitrile radicals
  • C07D213/79—Acids; Esters
• • 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
  • C09K19/3444—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 one nitrogen atom, e.g. pyridine

Definitions

• the invention relates to pyridine derivatives of the formula I.
• R 1 is an alkyl radical with 1-15 C atoms or an alkenyl radical with 2-15 C atoms, in which
• a CH 2 group can also be replaced by -O-, -CO-, -O-CO- or -CO-O-,
• R 2 ei.ne of the meanings of R 1 or an optically active radical
• R 3 is an alkyl group other than Y with 1 to
• Cyc in the following means a 1,4-cyclohexylene group, Phe a 1,4-phenylene group and PheX one or more times by F and / or Cl atoms and / or CH 3 , - and / or CN groups substituted 1,4-phenylene group.
• the compounds of the formula I can be used as components of liquid-crystalline phases, in particular for displays which are based on the principle of the twisted cell (TN displays), the guest-host effect, the ECB effect, the effect of the deformation Phases based on the effect of dynamic scattering or the SSFLC principle, or also for TFT or STN mixtures.
• liquid crystalline phases are required which have very low viscosities and particularly advantageous elastic constants.
• the object of the invention was to find new stable liquid-crystalline or mesogenic compounds which are suitable as components of liquid-crystalline phases.
• the compounds of the formula I are particularly suitable as components of liquid-crystalline phases. In particular, they can be used to produce stable liquid-crystalline phases for high-information displays with short switching times. Furthermore, certain compounds of formula I are also suitable as components of ferroelectric liquid crystal phases, for example for displays based on the SSFLC principle. With the provision of the compounds of the formula I, the range of liquid-crystalline substances which are suitable for the preparation of liquid-crystalline mixtures from various technical aspects is also very broadly widened.
• the compounds of formula I have a wide range of uses. Depending on the choice of the substituents, these compounds can serve as base materials from which liquid-crystalline phases are predominantly composed; However, it is also possible to add compounds of the formula I to liquid-crystalline base materials from other classes of compounds in order, for example, to optimize the electrical and / or optical anisotropy or other parameters of such a dielectric.
• the compounds of formula I are also suitable as intermediates for the preparation of other substances which can be used as constituents of liquid-crystalline phases.
• the compounds of the formula I are colorless in the pure state and form liquid-crystalline mesophases in a temperature range which is favorable for electro-optical use. They are very stable chemically, thermally and against light.
• the invention thus relates to the compounds of the formula I and to the use of the compounds of the formula I as components of liquid-crystalline phases.
• the invention further relates to liquid-crystalline phases containing at least one compound of the formula I and liquid-crystal display elements which contain such phases.
• R 1 , Z 1 , n, Z, A, A 1 , m and R 2 have the meaning given, unless expressly stated otherwise.
• the compounds of the formula I accordingly comprise compounds of the partial formula Ia (with two rings), Ib to Id (with three rings) and Ie to If (with four rings):
• those of the sub-formulas Ia, Ib, Ic and Id are particularly preferred.
• the preferred compounds of sub-formula Ia include those of sub-formulas Iaa to Iah:
• the preferred compounds of sub-formula Ib include those of sub-formulas Iba to Ibj:
• those of the sub-formulas Ibc, Ibd, Ibe, Ibh, Ibi and Ibj are particularly preferred.
• the preferred compounds of sub-formula Ic include those of sub-formulas Ica to Icj:
• the preferred compounds of sub-formula Id include those of sub-formulas Ida to Idd:
• Z 1 preferably denotes a single bond
• R 1 and R 2 are preferably alkyl, -O-alkyl, -OCO-
• Alkyl or oxaalkyl Alkyl or oxaalkyl.
• R 1 is particularly preferably alkyl and R 2 is alkyl, alkoxy or -OCO-alkyl.
• alkenyl groups are preferred for R 1 and / or R 2 .
• Substances of the formula I in which R 2 is an optically active radical of the formula are also particularly preferred
• optically active residues is very particularly preferred:
• Z 1 means -CH 2 CH 2 - or a single bond, preferably a single bond.
• Cyc means a trans-1,4-cyclohexylene group
• a 1 -O-CO-Phe.
• Phe is preferably an unsubstituted 1,4-phenylene group, but can also be substituted one or more times, preferably once or twice, by F, Cl, CH 3 and / or CN. Mono substitution by fluorine is preferred, and di-substitution in the 2,3-position by fluorine is particularly preferred.
• n is preferably 1 and m is preferably 0.
• alkyl radicals in the groups R 1 and / or R2 can be straight-chain or branched. They are preferably straight-chain, have 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 carbon atoms and accordingly preferably denote methyl,
• R 1 and / or R 2 are alkyl radicals in which one
• Alkoxy or "Oxaalkyl” or two (“Alkoxyalkoxy” or “Dioxaalkyl”) CH2 groups are replaced by O atoms, they can be straight-chain or branched. They are preferably straight-chain, have 2, 3, 4, 5,
• Branched groups of this type usually contain no more than one chain branch.
• R 1 and / or R2 represent an alkenyl radical, this can be straight-chain or branched. It is preferably straight-chain and has 2 to 10 carbon atoms. Accordingly, it preferably means 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.
• J6 0149564 encompasses the general formula, no explicit examples are available.
• JG 0149564 has a melting point of 85.1 ° and a clearing point of 92.9 °. In contrast, the
• the mesophase range is thus 10 to 12 times wider for the compounds according to the invention than for the compounds described above.
• the compounds Ig according to the invention are therefore much more suitable as components of liquid-crystalline phases.
• the compounds of formula I are prepared by methods known per se, as described in the literature (for example in the standard works such as Houben Weyl, Methods of Organic Chemistry, Georg-Thieme-Verlag, Stuttgart), and under reaction conditions which are suitable for the implementations mentioned are known and suitable. One can make use of variants which are known per se and are not mentioned here.
• Esters of the formula I can be obtained by esterifying corresponding carboxylic acids (or their reactive derivatives) with correspondingly 2-substituted pyridin-5-ols (or the reactive derivatives).
• Suitable reactive derivatives of the carboxylic acids mentioned are, in particular, the acid halides, especially the chlorides and bromides, furthermore the anhydrides, azides and esters, in particular alkyl esters with 1-4 C atoms in the alkyl group.
• Suitable reactive derivatives of the pyridin-5-ols mentioned are in particular the corresponding metal alcoholates, preferably an alkali metal such as Na or K.
• the reactions are preferably carried out in toluene / pyridine, starting from the acid chloride, or also with DCC (dicyclohexylcarbodiimide) in the presence of catalytic amounts of DMAP (dimethylaminopyridine), starting from the carboxylic acid itself.
• DCC diclohexylcarbodiimide
• DMAP dimethylaminopyridine
• Ethers of the formula I can be prepared by etherification of corresponding hydroxyl compounds, the hydroxyl compounds first being expediently converted into a corresponding metal derivative, for example by treatment with NaH, NaNH 2 , NaOH, KOH, Na 2 CO 3 or K 2 CO 3 , is transferred.
• This metal derivative can then be reacted with the corresponding alkyl halide, sulfonate or dialkyl sulfonate, advantageously in an inert solvent such as acetone, 1,2-dimethoxyethane, DMF or dimethyl sulfoxide or even an excess of aqueous or aqueous-alcoholic NaOH or KOH at temperatures between about 20 ° and 100 °.
• the ethane derivatives can also be prepared by hydrogenating the corresponding alkenes.
• the hydrogenations can be carried out by generally known methods.
• the starting compounds are either known or can be prepared by simple reactions known from the literature.
• the liquid-crystalline media according to the invention preferably contain 2 to 40, in particular 4 to 30, components as further constituents. These media very particularly preferably contain 7 to 25 components in addition to one or more compounds according to the invention.
• These further constituents are preferably selected from nematic or nematogenic (monotropic or isotropic) substances, in particular substances from the classes of azoxybenzenes, benzylidene anilines, biphenyls, terphenyls, phenyl- or cyclohexylbenzoates, cyclohexane-carboxylic acid phenyl or cyclohexyl esters, phenyl or cyclohexyl esters cyclohexylbenzoic acid, phenyl or cyclohexyl esters of cyclohexylcyclohexanecarboxylic acid, cyclohexylphenyl of benzoic acid, of cyclohehexylphenyl of be
• L and E which may be the same or different, each independently represent a bivalent radical from the group consisting of -Phe-, -Cyc-, -Phe-Phe-, -Phe- Cyc-, -Cyc-Cyc-, -Pyr-, -Dio-, -G-Phe- and -G-Cyc- as well as their mirror images formed group, whereby Phe unsubstituted or substituted by fluorine-substituted 1,4-phenylene, Cyc- 1,4-cyclohexylene or 1,4-cyclohexenylene, pyr pyrimidine-2,5-diyl or pyridine-2,5-diyl, dio 1,3-dioxane-2,5-diyl and G 2- (trans-1, 4-Cyclohexyl) ethyl, pyrimidine-2,5-diyl, pyridine-2
• one of the radicals L and E is Cyc, Phe or Pyr.
• E is preferably Cyc, Phe or Phe-Cyc.
• the media according to the invention preferably contain one or more components selected from the compounds of the formulas 1, 2, 3, 4 and 5, in which L and E are selected from the group Cyc, Phe and Pyr and at the same time one or more components selected from the compounds of Formulas 1, 2, 3, 4 and 5, in which one of the radicals L and E is selected from the group Cyc, Phe and Pyr and the other radical 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 from the group -Phe-Cyc-, -Cyc-Cyc-, -G-Phe- and -G-Cyc
• R 'and R "in the compounds of sub-formulas 1a, 2a, 3a, 4a and 5a each independently represent alkyl, alkenyl, alkoxy, alkenyloxy or alkanoyloxy having up to 8 carbon atoms. Most of these compounds are R1 and R" different from one another, one of these radicals usually being alkyl or alkenyl.
• R in the compounds of sub-formulas 1b, 2b, 3b, 4b and 5b, R "means -CN, -CF 3 , F, Cl or -NCS; R has the meaning given for the compounds of sub-formulas Ia to 5a and is preferably alkyl or Alkenyl, but also other variants of the proposed substituents in the compounds of the formulas 1, 2, 3, 4 and 5 are common. Many such substances or mixtures thereof are commercially available. All of these substances are obtainable by methods known from the literature or in analogy thereto .
• the media according to the invention preferably also contain components from the group of compounds 1b, 2b, 3b, 4b and 5b (group 2), the proportions of which are preferably as follows are:
• Group 1 20 to 90%, in particular 30 to 90%
• group 2 10 to 80%, in particular 10 to 50%
• the media according to the invention preferably contain 1 to 40%, particularly preferably 5 to 30%, of compounds according to the invention. Also preferred are media containing more than 40%, in particular 45 to 90% of compounds according to the invention.
• the media preferably contain three, four or five compounds according to the invention.
• the media according to the invention are produced in a conventional manner.
• the components are dissolved in one another, advantageously at elevated temperature.
• the liquid-crystalline phases according to the invention can be modified so that they can be used in all types of liquid-crystal display elements which have hitherto become known.
• Such additives are known to the person skilled in the art and are described in detail in the literature (H. Kelker / R. Hatz, Handbook of Liquid Crystals, Verlag Chemie, Weinheim, 1980).
• pleochroic dyes can be added to produce colored guest-host systems or substances to change the dielectric anisotropy, the viscosity and / or the orientation of the nematic phases.
• K crystalline solid state
• S smectic phase (the index indicates the phase type)
• N nematic state
• Ch cholesteric phase
• I isotropic phase.
• trans-4- (trans-4-pentylcyclohexyl) cyclohexane carboxylic acid (2-pentylpyridin-5-yl) ester with K 31 ° S B 181 ° N 183.1 ° I is obtained.
• trans-4- (trans 4-ethylcyclohexyl) cyclohexanecarboxylic acid (2-heptyl-pyridin-5-yl) ester trans-4- (trans-4-propylcyclohexyl) cyclohexanecarboxylic acid (2-heptyl-pyridin-5-yl) ester trans-4- (trans-4-butylcyclohexyl) cyclohexanecarboxylic acid (2-heptyl-pyridin-5-yl) ester trans-4- (trans-4-pentylcyclohexyl) cyclohexanecarboxylic acid (2-heptyl-pyridin-5-yl) ester trans-4- (trans-4-hexylcyclohexyl) cyclohexanecarboxylic acid (2-heptyl-pyridin-5-yl) ester trans-4- (trans-4-hexylcyclohexyl) cyclohe
• trans-4-ethylcyclohexane carboxylic acid (2-methyl-pyridin-5-yl) ester mp. 34 ° trans-4-propylcyclohexane carboxylic acid (2-methyl-pyridin-5-yl) ester, mp. 40 °, cp. 0 ° trans-4-butylcyclohexane carboxylic acid (2-methyl-pyridin-5-yl) ester, mp. 41 °, cp. 20 ° trans-4-pentylcyclohexane carboxylic acid (2-methyl-pyridin-5-yl) ester, mp. 48 °, cp.
• trans-4-ethylcyclohexanecarboxylic acid (2-hexyl-pyridin-5-yl) ester trans-4-propylcyclohexanecarboxylic acid (2-hexyl-pyridin-5-yl) ester trans-4-butylcyclohexanecarboxylic acid (2-hexyl-pyridine) - 5-yl) -ester trans-4-pentylcyclohexanecarboxylic acid- (2-hexyl-pyridine-5-yl) -ester trans-4-hexylcyclohexanecarboxylic acid- (2-hexyl-pyridin-5-yl) -ester trans-4-heptylcyclohexanecarboxylic acid - (2-hexyl-pyridin-5-yl) ester
• trans-4-pentylcyclohexane carboxylic acid (2-methoxy-pyridin-5-yl) ester is obtained.
• I trans-4- (trans-4-butylcyclohexyl) cyclohexylmethyl- ( 2-pentyl-pyridin-5-yl) ether
• trans-4-heptylcyclohexyl) cyclohexylmethyl- (2-pentyl-pyridin-5-yl) ether
• trans-4-octylcyclohexyl) trans
• the following example relates to a liquid-crystalline phase according to the invention.
• a liquid crystalline phase consisting of
• trans-4- (trans-4-propylcyclohexyl) cyclohexane carboxylic acid (4-propylphenyl) ester 5% trans-4- (trans-4-propylcyclohexyl) cyclohexane carboxylic acid (2-pentylpyridin-5-yl) ester, 5% trans-4-trans-4-butylcyclohexyl) cyclohexanecarboxylic acid (4-propylphenyl) ester, 5% trans-4- (trans-4-butylcyclohexyl) cyclohexanecarboxylic acid (2-pentylpyridin-5-yl) ester,

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6353084

Family Applications (1)

Country Status (7)

Cited By (2)

Families Citing this family (2)

Citations (4)

• 1988
  • 1988-04-28 DE DE3814346A patent/DE3814346A1/de not_active Withdrawn
• 1989
  • 1989-04-15 WO PCT/EP1989/000408 patent/WO1989010356A1/de not_active Application Discontinuation
  • 1989-04-15 JP JP1504480A patent/JPH02504035A/ja active Pending
  • 1989-04-15 EP EP89904791A patent/EP0365641A1/de not_active Withdrawn
  • 1989-04-26 CN CN89102622A patent/CN1037334A/zh active Pending
  • 1989-04-26 DD DD89327988A patent/DD283833A5/de not_active IP Right Cessation
  • 1989-12-27 KR KR1019890702461A patent/KR900700453A/ko not_active Application Discontinuation

Patent Citations (4)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events