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:
Sep. 17, 2013
Filed:
Sep. 27, 2007
Michael Stanek, Linz, AT;
Stefan Essl, Binzen, DE;
Monika Knopp, Rheinfelden, CH;
Erwin Kübel, Linz, AT;
Michael Stanek, Linz, AT;
Stefan Essl, Binzen, DE;
Monika Knopp, Rheinfelden, CH;
Erwin Kübel, Linz, AT;
DSM IP Assets B.V., Heerlen, NL;
Abstract
Improved method of production of 9-(Z)-retinoic acid, in which a) a β-formyl-crotonic acid C-Calkyl or phenyl ester is reacted with an isolated 9-(Z)—C-triarylphosphonium salt by the Wittig reaction in the presence of a base to the corresponding 9-(Z)-retinoic acid ester; which b) is then saponified with a base to the corresponding 9-(Z)-retinoic acid carboxylate and then, following protonation with an acid, the desired 9-(Z)-retinoic acid is obtained, and improved method for the enrichment and isolation of the 9-(Z)—C-triarylphosphonium salt.