反应详情

温度

55 °C

30.4 ml (57.47 mmol, 1.08 eq.) of a 20% solution of phosgene in toluene were added slowly at r.t. to a stirred solution of 6.26 g (53.44 mmol) L-valine (81a) in 63 ml dry THF. After the complete addition the mixture was heated at 55° C. for 4 h. Then a stream of nitrogen was bubbled through the solution and passed after that through a 1M aq. NaOH-solution for 20 min. before the solvent was evaporated. Recrystallization of the obtained residue from PE/Ether (2:1) yielded 3.62 g (25.29 mmol, 47.32%) (S)-4-Isopropyl-oxazolidine-2,5-dione (86) as a white solid.

1. additionAfter the complete addition the mixture
2. customThen a stream of nitrogen was bubbled through the solution
3. customfor 20 min.
4. customwas evaporated
5. customRecrystallization of the obtained residue from PE/Ether (2:1)