| abstract |
Bicyclic derivatives of the general formula <IMAGE> I wherein X1 is -S- or -SO-; X2 is -CO- or -CS-; R1 is hydrogen, halogen or lower alkyl optionally substituted by halogen or lower alkoxy; R2 and R3 are each independently hydrogen, lower alkyl, halogen, amino, lower alkylamino, di-lower alkylamino, acylamino, lower alkexy, lower alkoxymethoxy or a group OR4; R4 is hydrogen or an easily hydrolyzable group; R5 is hydrogen, optionally esterified carboxy or amidated (thio)carboxy, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted acyl or heterocyclyl; R6 and R7a are each independently hydrogen or lower alkyl; R7b is hydrogen, optionally substituted hydroxy, -NR-A or -N=B, in which R is hydrogen or lower alkyl, A is hydrogen, optionally substituted alkyl, lower cycloalkyl, iminoyl, (thio)acyl, esterified carboxy or amidated (thio)carboxy and B is lower alkylidene; R7a and R7b together represent oxo, lower alkoxycarbonylmethylidene or optionally substituted hydroxyimino; and R8 is hydrogen, optionally substituted alkyl, optionally esterified carboxy or amidated (thio)carboxy; provided that no more than two of R1-R3 are nitrogen-containing groups; no more than two of R1-R3 are oxygen containing groups and no more than two of R1-R3 are either nitrogen containing or oxygen containing groups; and pharmaceutically acceptable salts of the compounds of formula I carrying an acidic and/or basic substituent. The products are antimicrobially active. |