To provide a method for synthesizing (S)-4-{[3-[2-(dimethylamino) ethyl]-1H-indol-5-yl]methyl}-2-oxazolidinone by an improved process.

This method for synthesizing the oxazolidinone compound includes the following processes: (a) a process for forming a carbamate of formula (III) from methyl 4-nitro-(L)-phenylalaninate hydrochloride; (b) a process for reducing the compound of formula (III) to forma compound of formula (IV); (c) a process for reducing methyl ester group of the compound of formula (IV) to form a compound of formula (V); (d) a process for cyclizing the compound of formula (V) to form a compound of formula (VI); (e) a process for forming a diazonium salt from the compound of formula (VI) and the reducing the diazinium salt to form a compound of formula (VII); (f) a process for subjecting the compound of formula (VII) to Fischer's reaction to obtain the (S)-4-{[3-[2-(dimethylamino)ethyl]-1H-indol-5-yl]methyl}-2-oxazolidinone.