| 摘要 |
<p>NEW MATERIAL:A cephalosporin derivative of formula I (R1 is COOH, lower alkoxycarbonyl group, etc.; R2 is carbamoyl, carboxy lower alkyl group, etc.; B is 1-methyltetrazol-5-ylthio, acetoxy group, etc.; A is H or methoxy group) and its salt. EXAMPLE:7beta-{4-[(Carbamoyl)(carboxy)-methylene]-1, 3-dithietan-2-yl} carboxamide-7alpha-methoxy cephalosporanic acid. USE:Antibacterials characterized by the 1, 3-dithietane ring at the side chain of the 7-position of the cephalosporin nucleus, having powerful effects on Gram- negative bacteria, useful as feed additives and preservatives. PROCESS:A compound of formula II (R3 is H or protecting group) or its salt is reacted with a compound of formula III or its reactive derivative, and if necessary, the protecting group is removed to give the compound of formula I.</p> |
