| 摘要 |
PCT No. PCT/GB93/01092 Sec. 371 Date Dec. 7, 1994 Sec. 102(e) Date Dec. 7, 1994 PCT Filed May 26, 1993 PCT Pub. No. WO93/25551 PCT Pub. Date Dec. 23, 1993 <IMAGE> (I) A compound of formula (I) or a salt thereof, wherein R1 is hydrogen, methoxy or formamido; R2 is an acyl group, in particular that of an antibacterially active cephalosporin; CO2R3 is a carboxy group or a carboxylate anion, or R3 is a readily removable carboxy protecting group or a pharmaceutically acceptable salt-forming group or in vivo hydrolysable ester group; R4 represents hydrogen or up to four substituents, which may be present on any of the carbon atoms in the ring system shown, selected from alkyl, alkenyl, alkynyl, alkoxy, hydroxy, halogen, amino, alkylamino, acylamino, dialkylamino, CO2R, CONR2, SO2NR2 where R is hydrogen or alkyl, aryl and heterocyclyl, which may be the same or different and wherein any R4 alkyl substituent is optionally substituted by one or more substituents selected from the list from which R4 is selected; Y is O, S, SO or SO2; and m is 1 or 2, a process for its preparation, use as an antibiotic and intermediates thereto. |
