| abstract |
A cephalosporanic acid derivative possessing antibacterial activity and pharmaceutically acceptable salts thereof, and processes for preparing same, having the general formula ##STR1## wherein R 1 is hydrogen, aryl or a heterocyclic group n R 2 is pyridyl or styryl, and n R 3 is hydrogen, alkylthio or an unsubstituted or alkyl substituted heterocyclic group. |