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    • 3. 发明授权
    • Preparation of trans-4-alkyl-cyanoarylcyclohexanes
    • 反式-4-烷基 - 氰基芳基环己烷的制备
    • US4229367A
    • 1980-10-21
    • US39134
    • 1979-05-15
    • Bernhard GranwehrRene Gnehm
    • Bernhard GranwehrRene Gnehm
    • C07C51/36C07C67/00C07C253/00C07C255/57C09K19/30C07C121/64
    • C09K19/3003C07C51/36C07C2101/14
    • Trans-4-alkyl-cyanoarylcyclohexanes are prepared in a stereoselective manner from arylcarboxylic acids of the formula Ar-[Ar].sub.n -Ar-4-COOH, Ar being aryl and n being 0 to 2, by first converting such a carboxylic acid to a mixture of the cis and trans isomers of the corresponding cyclohexa-2,5-diene-4-carboxylic acid, esterifying the resulting isomer mixture with a lower alkanol and further hydrogenating the resulting esters/isomers to produce the cis and trans isomers of the corresponding cyclohexane-4-carboxylic acid esters, isomerizing the cis isomers in the mixture to the trans isomer thereby producing a mixture containing the trans isomer substantially free from cis isomer, stereospecifically saponifying the trans isomer, growing a carbon chain of desired length on the carboxyl group of the resulting carboxylic acid, reducing the carbonyl group thereof, and introducing a cyano group into the terminal aryl group. The resulting product is useful as a nematic liquid crystal.
    • 反式-4-烷基 - 氰基芳基环己烷以立体选择性方式由式Ar- [Ar] n -Ar-4-COOH的芳基羧酸制备,Ar为芳基,n为0至2,首先将这种羧酸转化为 将相应的环己二-2,5-二烯-4-羧酸的顺式和反式异构体的混合物,用低级链烷醇酯化所得异构体混合物,并进一步氢化所得酯/异构体以产生顺式和反式异构体 相应的环己烷-4-羧酸酯,将该混合物中的顺式异构体异构化为反式异构体,从而产生含有基本上不含顺式异构体的反式异构体的混合物,立体专一地皂化反式异构体,在羧基上生长所需长度的碳链 得到的羧酸基团,还原其羰基,并将氰基引入末端芳基。 所得产物可用作向列型液晶。