Derivatives of 7-aminocephalosporanic acid

摘要

Novel 3-acyloxymethyl-cephem compounds of the formula: <IMAGE> wherein R1 is hydrogen or an acyl group; X is a divalent group consisting of a carbon chain having 2 to 3 carbon atoms and a carbonyl or sulfonyl group at one terminal end thereof, said divalent group being either substituted or unsubstituted on the carbon chain; and Z is an organic acid residue, and salts thereof were found to be useful as starting materials for preparing cephalosporins of the formula: <IMAGE> wherein R2 stands for a residue of a nucleophilic compound and R1 has the same meaning as above.