| 摘要 |
<p>The present invention provides compounds of the general formula:- …<CHEM>… wherein R<1> is a hydrogen or halogen atom, a hydroxyl group or a lower alkyl or lower alkoxy radical, R<2> is a hydrogen atom or a lower alkyl or acyl radical, R<3> is an alkylene or lower alkenylene radical, optionally substituted by cyano, amino or protected amino group, and X is O, S, SO or SO2, the derivatives thereof on the carboxyl group; and the pharmaceutically acceptable salts thereof. …<??>The present invention also provides processes for preparing these compounds and pharmaceutical compositions containing them.</p> |
