摘要 |
<p>beta -Lactam antibiotics of formula (I) or a salt thereof, wherein R<1> is hydrogen, methoxy or formamido; R<2> is an acyl group; CO2R<3> is a carboxy group or a carboxylate anion, or R<3> is a readily removable carboxy protecting group; R<4> represents up to four substituents; X is S, SO, SO2, O or CH2; m is 1 or 2; and n is 0, useful in the treatment of bacterial infections in humans and animals.</p> |