A solution of (S)-3-(2-chloropyrimidin-4-yl)-4-isopropyloxazolidin-2-one (96 mg, 0.40 mmol) and 1-(4-chlorophenyl)ethanamine (204 mg, 1.31 mmol, 3.3 equiv) in DMSO (1 mL) was heated at 110° C. for 3 h. The reaction mixture was diluted with EtOAc (8 mL) and washed with water (30 mL). After separation, the aqueous phase was extracted with EtOAc (3×8 mL). Combined organics were dried over Na2SO4, filtered and concentrated. Silica gel column chromatography (EtOAc/Heptane 10 to 50%) provided (S)-3-(2-((R)-1-(4-chlorophenyl)ethylamino)pyrimidin-4-yl)-4-isopropyloxazolidin-2-one and (S)-3-(2-((S)-1-(4-chlorophenyl)ethylamino)pyrimidin-4-yl)-4-isopropyloxazolidin-2-one.
