Cephem compounds

摘要

The present invention relates to a compound of the formula [I]: wherein R¹ is lower alkyl, hydroxy(lower)alkyl or halo(lower)alkyl, and R² is hydrogen or amino protecting group, or R¹ and R² are bonded together and form lower alkylene or lower alkenylene; R³ is hydrogen or lower alkyl; R⁴ is R⁵ is carboxy or protected carboxy; and R⁶ is amino or protected amino, or a pharmaceutically acceptable salt thereof, a process for preparing a compound of the formula [I], and a pharmaceutical composition comprising a compound of the formula [I] in admixture with a pharmaceutically acceptable carrier.