| 摘要 |
Abstract of US 4289695 (A) Improved process for converting a penicillin sulfoxide ester to a 2-chlorosulfinylazetidin-4-one intermediate which on cyclization affords a 3-exomethylenecepham sulfoxide, wherein the penicillin sulfoxide ester is reacted with an N-chloro halogenating agent in the presence of a cross-linked polyvinylpyridine polymer to provide the 2-chlorosulfinylazetidin-4-one. |
