| abstract |
Compounds of the formula <IMAGE> (I) in which R1 is lower alkyl substituted by hydroxy or by protected hydroxy, R2 represents carboxy or functionally modified carboxy, and R3 represents amino, lower alkyl-substituted amino, substituted methyleneamino or protected amino, optical isomers of compounds of the formula I, mixtures of these optical isomers, and salts of such compounds of the formula I that have a salt-forming group have antibiotic activity. The compounds of the formula I are manufactured according to processes that are known per se. |