| 摘要 |
<p>Cephalosporin antibiotics of the general formula <IMAGE> (wherein R<a> and R<b>, which may be the same or different, each represent a C1-4 alkyl group or R<a> and R<b> together with the carbon atom to which they are attached form a C3-7 cycloalkylidene group; and R<4> represents hydrogen or a 3- or 4-carbamoyl group) exhibit broad spectrum antibiotic activity, the activity being unusually high against gram-negative organisms such as strains of Pseudomonas organisms. A particular antibiotic compound of formula (I) possessing excellent antibacterial activity against strains of Pseudomonas organisms, as well as other valuable therapeutic properties, is (6R,7R)-7-[(Z)-2- (2-aminothiazol-4-yl)-2-(2-carboxyprop-2-oxyimino)acetamido]-3-(1- pyridiniummethyl)-ceph-3-em-4 carboxylate. The invention also includes the non-toxic salts and non-toxic metabolically labile esters of compounds of formula (I). Also described are compositions containing the antibiotics of the invention and processes for the preparation of such antibiotics.</p> |
