Intermediates for cephalosporin compounds

摘要

Cephalosporin antibiotics having a 3-position substituent of the formula: <IMAGE> are described; wherein R1 is hydrogen or certain substituted alkyl groups, Z is CH or N, R2 and R3 are hydroxy or in vivo hydrolysable esters thereof, (R12)n represents various optional substituents and X=Y is an olefin, oxime, azo or related group. Processes for their preparation and use are described.