Synthesis and Antibacterial Activity of New Tetracyclic Triazolothiadiazino Fluoroquinolones

A series of novel 9-fluoro-10-(4-methylpiperazin-1-yl)-3-substituted-8-oxo-8H-[1,2,4] triazolo[3,4-b]thiadiazino[6,5,4-ij]quinoline-7-carboxylic acids was prepared by a facile synthetic method and the in vitro antibacterial activity against Gram-postive (G+) and Gram negative (G-) bacteria was primarily evaluated.