Process for preparing a 3-formylcephem derivative.

摘要

The present invention provides a process for preparing a 3-formylcephem derivative represented by the formula (2) which comprises oxidizing in the presence of oxygen a 3-halomethylcephem derivative represented by the formula (1) wherein R<1> is amino group or protected amino group, R<2> is hydrogen atom or a carboxylic acid protective group, X is halogen atom.