Compounds of the formula ##STR1## in which R is hydrogen or an acyl group, R.sub.1 is hydrogen or lower alkyl, and R.sub.2 is hydrogen, an alkali metal cation, or a readily removable ester forming group, are active antibiotics or intermediates thereto.
Cephalosporins represented by the formula X-S-Y wherein X is a deacetoxycephalosporinyl group and Y is a 6-membered heterocyclic group containing 1-3 nitrogens at least one of which is substituted and at least one of which is adjacent to a carbonyl group, said heterocyclic group containing one or more ring substituents and being characterized by being non-aromatic and not enolizable to an aromatic form.