| abstract |
Compounds of the general formula:n in which R,, R z , R 3 , X and Z are as defined herein, and their pharmaceutically acceptable salts;n especially those subject to the following provisos:n (i) when X is S, Z is O or =NR 7 (R, being as defined herein); (ii) when X is 0, Z is 0, S or =NR 7 ; (iii) when X is -CH 2 -, Z is =NR 7 ; (except that when R 7 is H or C 1 -C 6 alkyl and R 2 is C 1 -C 6 alkyl, then R, cannot be acylamino;n (iv) when X is (CH 2 ) 2 , Z is =NR 7 ; and their pharmaceutically acceptable salts. These compounds are antibacterial agents which can be incorporated into pharmaceutical compositions or used as intermediates in the preparation of such agents. |