Synthesis and in vitro antibacterial activity of 7-(4-alkoxyimino-3-amino-3-methylpiperidin-1-yl)fluoroquinolone derivatives.

A series of novel 7-(4-alkoxyimino-3-amino-3-methylpiperidin-1-yl)fluoroquinolone derivatives were designed, synthesized and characterized by (1)H NMR, MS and HRMS. These fluoroquinolones were evaluated for in vitro antibacterial activity against representative Gram-positive and Gram-negative strains. All of the title compounds have considerable activity against the twelve strains, and exhibit exceptional potency in inhibiting the growth of Staphylococcus aureus, Staphylococcus epidermidis and Klebsiella pneumoniae (minimum inhibitory concentration (MIC): 0.06-8 microg/mL). The most active compound 17 is 4-fold more potent than levofloxacin against S. aureus and S. epidermidis, 32-fold more potent than levofloxacin against Streptococcus pneumoniae, and 16-fold more potent than IMB against K. pneumoniae.