反应详情

A solution of the (RS)-4-(5-bromo-2-fluoro-phenyl)-4-methyl-oxazolidin-2-one (20.2 g) in ethanol/dichloromethane/heptane (4/2/2) was divided in 1 g aliquots which were separated on chiral HPLC (Chiralpak AD) using a 90:10-mixture of ethanol and heptane as the eluent. The first eluting enantiomer (retention time: 7.98 min), the (R)-(−)-4-(5-bromo-2-fluoro-phenyl)-4-methyl-oxazolidin-2-one (intermediate C5A), was obtained as a brownish crystalline solid (9.154 g, 45.3% of theory), and the second eluting enantiomer (retention time: 12.19 min), the (S)-(+)-N-[1-(5-bromo-2-fluoro-phenyl)-2-hydroxy-1-methyl-ethyl]-2-chloro-acetamide, was also obtained as a light brown crystalline solid (9.25 g, 45.8% of theory), with e.e. >99.5% each.

1. customwere separated on chiral HPLC (Chiralpak AD)