New cephalosporin compounds of the formula: ##STR1## wherein R.sub.1 is hydrogen or hydroxy, R.sub.2 is a substituted alkanoyl group, R.sub.3 is hydrogen, carbamoyloxy, alkanoyloxy or a heterocyclic-thio group which may have suitable substituents, and R.sub.4 is carboxy or protected carboxy.
New cephalosporin compounds of the formula: ##STR1## wherein R.sub.1 is hydrogen or hydroxy, R.sub.2 is a substituted alkanoyl group, R.sub.3 is hydrogen, carbamoyloxy, alkanoyloxy or a heterocyclic-thio group which may have suitable substituents, and R.sub.4 is carboxy or protected carboxy.