Cephalosporins and homologues, preparations and pharmaceutical
申请人:——
公开号:US06001997A1
公开(公告)日:1999-12-14
.beta.-Lactam antibiotics of formula (I) or a salt thereof, wherein R.sup.1 is hydrogen, methoxy or formamido; R.sup.2 is an acyl group; CO.sub.2 R.sup.3 is a carboxy group or a carboxylate anion, or R.sup.3 is a readily removable carboxy protecting group; R.sup.4 represents up to four substituents; X is S, SO, SO.sub.2, O or CH.sub.2 ; m is 1 or 2; and n is 0, useful in the treatment of bacterial infections. ##STR1##