Process for preparation of 3-halomethylcephems

摘要

3-Halomethyl-3-cephems are provided by reacting a 3-methylenecepham with an alkali metal salt of a lower alcohol or a bicyclic amidine base in the presence of a positive halogenating agent at a temperature ranging from -80 DEG to about 20 DEG C. The 3-halomethylcephems provided by this invention are useful intermediates for the preparation of known cephalosporin antibiotics.