US Patent 8703939 Method for preparing (R)-3-(3-fluoro-4-(1-methyl-5,6-dihydro-1,2,4-triazin-4(1H)-yl)phenyl)-5-(substituted methyl)oxazolidin-2-one derivatives

Provided are a method for preparing (R)-3-(3-fluoro-4-(1-methyl-5, 6-dihydro-1,2,4-triazin-4(1H)-yl)phenyl)-5-(substituted methyl) oxazolidin-2-one derivatives, which are oxazolidinone antibiotic compounds having a cyclic amidrazone group, represented by Chemical Formula 1, and intermediates thereof, and uses 3,4-difluoro-4-nitrobenzen as a starting material. According to the preparation method of the present invention, (R)-3-(3-fluoro-4-(1-methyl-5, 6-dihydro-1,2,4-triazin-4(1H)-yl)phenyl)-5-(substituted methyl) oxazolidin-2-one derivatives, which are useful as oxazolidinone antibiotics, can be prepared in high purity and high yield in a simpler manner than conventional methods.