| abstract |
"cefem compounds". The present invention relates to a compound of the formula [I]: where R1 is lower alkyl, hydroxy-alkyl (lower) or halo-alkyl (lower), and R2 is hydrogen or amino protecting group, or R1 and R2 are linked together and form lower alkylene or lower alkenylene; R3 is hydrogen or lower alkyl; R4 and 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. |