The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 21, 1980
Filed:
May. 15, 1979
Bernhard Granwehr, Zofingen, CH;
Rene Gnehm, Kungoldingen, CH;
Siegfried Aktiengesellschaft, , CH;
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.