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:
May. 10, 1994
Filed:
Feb. 22, 1993
Michael S Ashwood, Bishops Stortford, GB;
Brian C Bishop, Bishops Stortford, GB;
Peter G Houghton, Bassingbourn, GB;
Guy R Humphrey, Bell Mead, NJ (US);
Merck Sharpe & Dohme Ltd., Hertfordshire, US;
Abstract
A process for preparing a single enantiomer of a 4-aryloxyazetidin-2-one derivative in optically pure form comprises reacting a hindered vinyl ester with chlorosulphonyl isocyanate; displacing the hindered acyloxy group with a phenolic derivative containing a protected carboxy group; deprotecting the carboxylate moiety; resolving with a chiral amine; filtering; and regenerating the desired enantiomer by acidification. A method for enriching the product obtained from the acyloxy displacement step in favour of the desired enantiomeric form, by treating with an asymmetric catalyst such as a chiral alkaloid derivative, is provided; as also is a method for racemising the unwanted antipode of the desired 4-aryloxyazetidin-2-one enantiomer. The invention further provides novel enantiomers based on the 4-aryloxyazetidin-2-one ring structure.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile