| 摘要 |
<p>The present invention relates to an improved process whereby a penicillin sulfoxide ester is reacted with an N-chloro halogenating agent at a temperature of from about 75.degree.C. to about 135.degree.C. and in the presence of an alkylene oxide and calcium oxide to produce a 2-chloro-sulfinylazetidin-4-one intermediate. The intermediate, upon separation from the alkylene oxide, calcium oxide, and any conversion products of both the alkylene oxide and calcium oxide, can be cyclized in the presence of a Friedel-Crafts catalyst to produce a 3-exomethylenecepham sulfoxide.</p> |
