Patents by Inventor Bernhard Granwehr

Bernhard Granwehr has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4229367
    Abstract: 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.
    Type: Grant
    Filed: May 15, 1979
    Date of Patent: October 21, 1980
    Assignee: Siegfried Aktiengesellschaft
    Inventors: Bernhard Granwehr, Rene Gnehm