BETA-LACTAM ANTIBIOTICS,THEIR PREPARATION AND PHARMACEUTICAL COMPOSITIONS CONTAINING THEM

摘要

Antibacterially active and animal growth-promoting novel beta -lactam compounds of the formula in which R1 represents the radical Y representing N or CR9, or Y-R7 representing >C=O or >C=N-R7, Z representing O, S, or NR10, and R2 represents hydrogen or a protective group.