- Method for preparing optically pure 5,7-difluoro-1,2,3,4-tetrahydronaphthalene-2-amine and salts thereof
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The invention discloses a method for preparing optically pure 5,7-difluoro-1,2,3,4-tetrahydronaphthalene-2-amine as shown in formulas a and b and salts thereof. The method comprises the following steps: (1) reacting 3,5-difluorophenylacetic acid with SOCl2 in the presence of a solvent to generate acyl chloride, and then carrying out Friedel-Crafts reaction on the acyl chloride and ethylene under the action of aluminum trichloride; (2) reacting 5,7-difluoro-3,4-dihydronaphthalene-2(1H)-ketone with amide in an organic solvent under an acid catalysis condition, and performing dehydrating to generate enamine; (3) performing catalytic hydrogenation on enamine in the presence of a chiral catalyst to prepare an optically pure intermediate amide; and (4) hydrolyzing the amide under an acidic or alkaline condition to obtain the optically pure 5,7-difluoro-1,2,3,4-tetrahydronaphthalene-2-amine (a or b) and the form of the salts thereof. The invention provides the method for preparing the optically pure 5,7-difluoro-1,2,3,4-tetrahydronaphthalene-2-amine and salts thereof, which is simple, convenient and easy to industrial production.
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Paragraph 0012; 0033; 0035-0036
(2021/10/27)
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- Important intermediate of nepicastat, and enzymatic synthesis method thereof
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The invention discloses an important intermediate of nepicastat, and an enzymatic synthesis method thereof. The important intermediate concretely is (R)-5,7-difluoro-1,2,3,4-tetrahydronaphthalene-2-ol. The raw material of the synthesis method is 3,5-diflu
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Paragraph 0012; 0014; 0020
(2020/05/01)
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- Design, synthesis and physical properties of new liquid crystal materials having a fluoro-substituted tetrahydronaphthalene structure for active matrix LCD
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Liquid crystal materials having a fluoro-substituted tetrahydro-naphthalene structure were designed for active matrix LCD. 6-Aryl-5-fluoro-1,2,3,4- tetrahydronaphthalenes and 5,6-difluoro-1,2,3,4-tetrahydronaphthalenes were prepared by regioselective fluo
- Kusumoto, Tetsuo,Saito, Yoshitaka,Nagashima, Yutaka,Negishi, Makoto,Takehara, Sadao,Iwashita, Yoshinori,Takeuchi, Kiyofumi,Takatsu, Haruyoshi,Pithart, Corneria,Frings, Rainer B.,Lachowicz, Artur,Grahe, Gerwald F.
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p. 155/[1197]-161/[1203]
(2007/10/03)
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- COMPOUND HAVING TETRAHYDRONAPHTHALENE SKELETON AND LIQUID CRYSTAL COMPOSITION CONTAINING THE SAME
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A tetrahydronaphthalene derivative represented by the general formula (I) and a liquid crystal composition containing the same. A compound represented by the general formula (I) shows superior liquid crystallinity and co-solubility with conventional liquid crystal compounds and compositions. Furthermore, addition of such a compound enables the threshold voltage to be significantly reduced with almost no deleterious effect on the responsiveness. In addition, a compound of the present invention can also be easily produced industrially, is colorless, and is chemically stable. Consequently, liquid crystal compositions containing such a compound are extremely useful as liquid crystals, and are particularly suitable for liquid crystal displays requiring a wide operating temperature range, low voltage driving and a high response speed.
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- FUSED RING COMPOUND
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A novel compound represented by the general formula (I), and a nematic liquid crystal composition incorporating the same. A compound represented by the general formula (I) can be produced industrially extremely easily, as shown in the examples, displays superior compatibility with current general purpose host liquid crystals as a nematic phase, and also shows little crystal precipitation at low temperatures. Moreover, by addition of a small amount of such a compound to a host liquid crystal, the liquid crystal temperature range at low temperatures can be effectively widened without any significant worsening of the various characteristics of the liquid crystal material. Consequently, a compound of the present invention is an extremely useful liquid crystal material which is suitable for various liquid crystal display elements which require a broad operating temperature range.
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- Benzocycloalkylazolethione derivatives
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The present invention relates to novel benzocycloalkylazolethione compounds which are dopamine β-hydroxylase inhibitors in which the benzocycloalkyl portion of the compound is selected from indanyl, 1,2,3,4-tetrahydronaphthalenyl and 6,7,8,9-tetrahydro-5H-benzocycloheptenyl (in which the benzo is optionally substituted with one to three substituents) and the azolethione portion of the compound is selected from 2-thioxo-2,3-dihydro-1H-imidazol-3-yl, 5-thioxo-4,5-dihydro-1H-[1,2,4]triazol-4-yl and 5-thioxo-4,5-dihydro-1H-[1,2,4]triazol-1-yl (each optionally substituted with one to three substituents); and the prodrugs, pharmaceutically acceptable salts, individual isomers and mixtures of isomers and the methods of using and preparing such benzocycloalkylazolethione compounds.
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