Cephalosporin esters with antibacterial activity

Claim 1

A compound of the formula ##SPC3## wherein: ##EQU2## n is 0 to 4; R is hydrogen, alkyl having 1 to 8 carbon atoms, cycloalkyl of 3 to 6 carbon atoms, phenyl, C 1 -C 4 phenalkyl, pyridyl, thienyl, or pyrrolyl; R 1 is hydrogen, methyl or ethyl; R 2 and R 3 are each hydrogen, alkyl having 1 to 6 carbon atoms, phenyl, pyridyl, or thienyl; R 4 and R 5 are each hydrogen or alkyl of 1 to 4 carbon atoms; R 6 is alkyl having 1 to 4 carbon atoms, phenyl, phenalkyl having 1 to 4 carbon atoms, pyridyl, thiadiazolyl, amino or C 1 -C 4 alkylamino; X is NH or oxygen; and each phenyl group is unsubstituted or substituted with one or two substituents selected from the group consisting of alkyl having 1 to 6 carbon atoms, alkoxy having 1 to 4 carbon atoms, hydroxy, amino, NHR 1 , N(R 1 ) 2 , nitro, fluoro, chloro, bromo, or carboxy.