| 摘要 |
beta -Lactam antibiotics of the formula (Ia) or pharmaceutically acceptable salts or pharmaceutically acceptable in vivo hydrolysable esters thereof, and the use thereof, are disclosed: <CHEM> wherein R is hydrogen, methoxy or formamido; R<1> is an acyl group, in particular that of an antibacterially active cephalosporin; R<2> is optionally substituted alkyl, acyl, alkoxycarbonyl, halogen, aryl, heterocyclyl, carboxy, carboxamido, or cyano; CO2R3 is carboxy or a carboxylate anion; X is S,SO,SO2,O or CH2; and n is zero or an integer from 1 to 5. Processes for the preparation of compounds together with intermediates for use therein are disclosed. |
