The preliminary results of ant ibacterial activities revealed t hat 4a,4b showed moderate antibacterial activitie s against Gram positive bacteria.

• 初步体外抗菌试验结果表明 ；所合成的头孢菌素衍生物 4 a；4 b对革兰氏阳性菌显示出中等程度的抑制活性 .