Cephalosporin compounds

Abstract

Cephalosporin compounds represented by the general formula ##STR1## wherein R represents a group shown by formula ##STR2## wherein R.sup.1 represents a hydrogen atom or a lower alkyl group of 1-3 carbon atoms and R.sup.2 represents a hydrogen atom, a lower alkyl group of 1-3 carbon atoms, a phenyl group which may be substituted by an amino or hydroxy group, a cyano group, a carboxy group, or a carboxymethyl group; said R.sup.1 and R.sup.2 may form a cycloalkylidene group of 4-6 carbon atoms together with the carbon atom to which they are bonded) or a group shown by formula --CH.sub.2 --R.sup.3 (wherein R.sup.3 represents a hydrogen atom, a halogenomethyl group, a carbamoyl group, a carboxymethyl group, .alpha.4-carboxy-3-hydroxyisothiazol-5-yl-thiomethyl group, or .alpha.2-carboxyphenylthiomethyl group); R' represents a group shown by formula ##STR3## (wherein R.sub.a represents a carboxy group, a cyano group, or a carbamoyl group which may be substituted by a lower alkyl group of 1-3 carbon atoms and R.sub.b represents a hydrogen atom or an amino group) or a group shown by formula ##STR4## (wherein R.sub.a and R.sub.b have the same significance as above); and the waveline .about. shows an anti-form or syn-form bond and the salts thereof. They possess excellent antibacterial activities against gram positive bacteria and gram negative bacteria, in particular, pseudomonas aeruginosa and are useful as anti-bacterial agents.