Abstract: The present invention relates to a cephalosporin compound represented by the following general formula (I), its pharmaceutically acceptable non-toxic salt, physiologically hydrolyzable ester, hydrate or solvate, or isomers thereof, which is useful as an antibiotic agent: ##STR1## in which R.sup.1 represents hydrogen or an amino-protecting group,R.sup.2 and R.sup.3 can be identical or different and each represent hydrogen or a hydroxy-protecting group, orR.sup.2 and R.sup.3 together can form a diol-protecting cyclic group,R.sup.4 represents hydrogen or a carboxyl-protecting group,R.sup.5 represents hydrogen, C.sub.1-4 alkyl, alkoxycarbonyl, carboxyl or sulfomethyl,R.sup.6 represents hydrogen, amino or substituted amino, andR.sup.7 represents C.sub.1-4 alkyl, amino or substituted amino, orR.sup.5 and R.sup.6 together with the carbon atoms to which they are attached can form a 3 to 7-membered cyclic group, orR.sup.6 and R.sup.

Abstract: The present invention relates to novel cephalosporin compounds, pharmaceutically acceptable non-toxic salts, physiologically hydrolyzable esters, hydrates and solvates and isomers thereof which possess potent and broad antibacterial activities. The compounds of the present invention have a (4-amino-1-substituted-alkapyrimidinium-4-yl)thiomethyl group in 3-position of the cephem nucleus and is specifically represented by the following formula(I): ##STR1## wherein: R.sup.1 is a hydrogen atom or a C.sub.1-4 alkyl, C.sub.2-4 alkenyl, C.sub.2-4 alkynyl or --C(R.sup.A)(R.sup.B)COOH group wherein R.sup.A and R.sup.B are independently a hydrogen atom or a C.sub.1-4 alkyl group, or form a C.sub.3-7 cycloalkyl group together with the carbon atom to which they are attached;R.sup.2 is an unsubstituted or substituted amino, C.sub.1-4 alkyl or C.sub.3-7 cycloalkyl group; andn is an integer ranging from 2 to 7.