发明名称 |
Improved process for the preparation of chiral 4-aryloxyazetidinones. |
摘要 |
<p>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.</p> |
申请公布号 |
EP0500171(A2) |
申请公布日期 |
1992.08.26 |
申请号 |
EP19920200394 |
申请日期 |
1992.02.12 |
申请人 |
MERCK SHARP & DOHME LTD. |
发明人 |
ASHWOOD, MICHAEL STEWART;BISHOP, BRIAN CHRISTOPHER;HOUGHTON, PETER GRENVILLE;HUMPHREY, GUY R. |
分类号 |
C07D205/08 |
主分类号 |
C07D205/08 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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