The treatment of hydrazide (16) with several aldehydes afforded N′-[(2-hydroxyphenyl)methylen]- (20), N′-[(3-hydroxy-4-methoxy phenyl)methylen]- (21) or N′-[1H-indol-3-ylmethylene]-2-[4-(2-methoxyphenyl)piperazin-1-yl]acetohydrazide (22). Then, compounds 14, 18, 19 and 22 were condensed with 7-[4-(chloroacetyl)piperazin-1-yl]-1-ethyl-6-fluoro-4-oxo-1,4-dihydroquinoline-3-carboxylic acid (3) that was obtained