Aim To study the structure-activity relationship of antibacterial oxazolidinone derivatives. Methods Seven （S） -5- （ heterocycle methylene） -3- （3-fluoro-4-morpholin-4-yl-phenyl） -oxazoli- din-2-ones were synthesized by the substitution of （S）-[ 3-（3-fluoro-4-morpholin-4-yl-phenyl）-oxazohdin-2-one-5-yl]-methanol mesylate with some secondary amines and the structures of the product were confirmed by ^1H NMR and elemental analyses or MS. Results None of the seven compounds showed potent activity against the tested 20 strains of bacteria in vitro. Conclusion The replacement of 5- acetylaminometyl of Linezolid by 5-（heterocycle methylene） lost the antibacterial activity.
