ABSTRACT
<p><b>AIM</b>To explore new agents of quinolone derivatives with high activity against Gram-positive organisms.</p><p><b>METHODS</b>dl-7-(4,4-Dimethyl-3- aminomethylpyrrolidinyl)-quinolones were designed and synthesized, and their activity against Gram-positive organisms was tested in vitro.</p><p><b>RESULTS</b>Ten target compounds were obtained. The structures of these compounds were confirmed by 1H NMR, MS. The target compounds with dl-4,4-dimethyl-3-( methyl) aminomethylpyrrolidine side chains had high activity against Gram-positive organisms. Especially the MIC values of compound 22 for 4 strains of Gram-positive resistant bacteria (two strains of MRSA and two of MRSE) were 0.015 -0.5 mg x L(-), which exhibited more potent activities than gatifloxacin (4 - 128 times). Its MIC value for Pseudomonas aeruginosa 03-5 (0.008 mg x L(-1)) was 4 times as that of gatifloxacin (0.03 mg x L(-1)).</p><p><b>CONCLUSION</b>The compound 22 showed high activity against Gram-positive organisms in vitro and it is worth of more investigation.</p>