反应详情

A solution of 1.95 g of (RS)-4-(3-bromo-phenyl)-4-(4-difluoromethoxy-3-methyl-phenyl)-4,5-dihydro-oxazol-2-ylamine (Building Block S) in dichloromethane was divided in 200 mg aliquots which were separated on chiral HPLC (Chiralpak AD) using a 92:8-mixture of heptane and isopropanol as the eluent. The fractions showing e.e. values in the range of 99.7% to 98.4% of the first eluting enantiomer were combined to give 994 mg of the (S)-(+)-4-(3-bromo-phenyl)-4-(4-difluoromethoxy-3-methyl-phenyl)-4,5-dihydro-oxazol-2-ylamine as a colourless oil which crystallised on standing. The later eluting enantiomer (R)-(−)-4-(3-bromo-phenyl)-4-(4-difluoromethoxy-3-methyl-phenyl)-4,5-dihydro-oxazol-2-ylamine was isolated to give 628 mg (96.8% e.e.) as a colourless oil which crystallised on standing. In addition, a fraction (137 mg) consisting of both isomers was also obtained.

1. customwere separated on chiral HPLC (Chiralpak AD)