Cephem compounds

摘要

The invention relates to novel cephem compounds of high antimicrobial activity of the formula: <IMAGE> wherein R1 is amino or lower alkanoylamino, R2 is lower alkyl, lower alkynyl, carboxy (lower) alkyl or esterified carboxy (lower) alkyl, R3 is amino or lower alkanoylamino, and X is hydrogen or halogen; and pharmaceutically acceptable salts thereof.