反应详情

A solution of 63.0 g (0.52 mol) of [R]-(+)-1-phenylethylamine in 800 ml of acetonitrile was added with stirring to a solution of 204.1 g (1.04 mol) of rac. 2-(p-fluorophenyl)-3-methylbutyric acid in 1200 ml of acetonitrile. After 1 hour the crystalline precipitate was filtered off, washed with 300 ml of acetonitrile and dried overnight under reduced pressure at 50°. After repeated recrystallization from ethanol, the corresponding salt was obtained as colorless crystals, m.p. 209°-210°. The salt was suspended in ether and treated with 3N hydrochloric acid to pH 1. The ethereal solution was washed with water, dried and evaporated under reduced pressure, yielding [R]-(-)-2-(p-fluorophenyl)-3-methylbutyric acid, m.p. 56°-57°; [α]D20 =-48.4° (c=1, methanol).

1. filtrationAfter 1 hour the crystalline precipitate was filtered off
2. washwashed with 300 ml of acetonitrile
3. customdried overnight under reduced pressure at 50°
4. customrecrystallization from ethanol
5. customthe corresponding salt was obtained as colorless crystals, m.p. 209°-210°
6. washThe ethereal solution was washed with water
7. customdried
8. customevaporated under reduced pressure