PROCESS OF CYCLIZATION TO FORM CEPHEM RING AND INTERMEDIATE PRODUCTS FOR SAME

摘要

An intermediate represented by following formula for synthesizing 3-hydroxy-3-cephem compounds 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.