abstract |
This invention relates to novel cephem compounds of high antimicrobial activity comprising the syn-isomers of 7-substituted-3-cephem-4-carboxylic acid esters of the formula: ##STR1## wherein R is lower alkanoyloxy (C 2 -C 6 )alkyl, isobutyryloxymethyl, 2-ethylbutyryloxymethyl or 3,3-dimethylbutyryloxymethyl, n or salts thereof. |