| 摘要 |
<p>Compounds of the general formula: <CHEM> in which R1, R2, R3, X and 2 are as defined herein, and their pharmaceutically acceptable salts; especially those subject to the following provisos: (i) when X is S, Z is O or =NR7 (R7 being as defined herein); (ii) when X is O, Z is O, S or =NR7; (iii) when X is -CH2-, Z is =NR7; (except that when R7 is H or C1-C6 alkyl and R2 is C1-C6 alkyl, then R1 cannot be acylamino; (iv) when X is (CH2)2, Z is=NR7; 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.</p> |
