CEPHALOSPORIN ANTIBIOTICS

摘要

Cephalosporin antibiotics of general formula: (I) (wherein Ra and Rb, which may be the same or different, each represent a C1-4 alkyl group or Ra and Rb together with the carbon atom to which they are attached form a C3-7 cycloalkylidene group, and Y represents a C-linked 5- or 6-membered heterocyclic ring containing at least one nitrogen atom, which ring may also contain one or more sulphur atoms and/or may be substituted by a C1-4 alkyl group) exhibit broad spectrum antibiotic activity, the activity being unusually high against gram-negative organisms such as strains of Pseudomonas organisms. Also described are compositions containing the antibiotics of the invention and processes for the preparation of the antibiotics.