| abstract |
New cephem compounds of the formula: <IMAGE> in which R<1> is a group of the formula: <IMAGE> wherein X is hydrogen or halogen, Y is hydrogen or hydroxy and R<5> is amino or protected amino group; R<2> is hydrogen or aliphatic hydrocarbon group which may have suitable substituent(s), R<3> is carboxy or protected carboxy group; and R<4> is ethyl, cyanomethyl, carboxymethyl, protected carboxymethyl or aminomethyl; and pharmaceutically acceptable salts thereof have antimicrobial activity and can be incorporated into pharmaceutical compositions. New compounds of the formula: <IMAGE> wherein R@ is carboxy(lower)alkyl or protected carboxy(lower)alkyl, R<3> is carboxy or protected carboxy group, and R<5> is amino or protected amino group, and salts thereof are also antimicrobial agents. |