UN PROCEDIMIENTO PARA PREPARAR COMPUESTOS DE CEFEM

摘要

Antibacterial compounds represented by the following formula including their pharmaceutically acceptable salts and esters; process for preparing them; pharmaceutical preparation comprising them; and method for combating infections by administering them: (wherein Hal is halogen; R1 is hydrogen or an amino-protecting group; R2 is alkyl; and R3 is hydrogen or a carboxy-protecting group.