CYCLIZATION TO FORM CEPHEM RING AND INTERMEDIATES THEREFOR

摘要

An intermediate represented by following formula for synthesizing 3-hydroxy-3-cephem compounds. or wherein A and B each is a hydrogen or amino substituent: R is a hydrogen or thiol substituent; Hal is a halogen; X is a hydroxy or carboxy protecting group; the broken line between A and R shows that when R and B are hydrogens. and A is a carboxylic acyl. the substituents can be combined to form an azetidinothiazoline bicyclic ring: and the enamine derivatives thereof.