反应详情

D-Asparagine 1 (195.0 g, 1.299 mol) and KBr (461 g, 3.87 mol) were dissolved in 3M H2SO4 (1720 ml). The solution was cooled in an ice-MeOH bath and stirred while a solution of NaNO2 (111.5 g. 1.62 mol) in H2O (200 ml) was added dropwise over 85 minutes. The temperature of the reaction mixture was kept at -5° during the addition and for an additional 60 minutes. The white precipitate was collected, washed twice with ice-cold water, and dried i.v. to give the bromo derivative 2 (198.9 g, 78%): [α]D +69.0° (C., 4.63, EtOH). ##STR82##

1. temperatureThe solution was cooled in an ice-MeOH bath
2. additionwas added dropwise over 85 minutes
3. additionThe temperature of the reaction mixture was kept at -5° during the addition and for an additional 60 minutes
4. customThe white precipitate was collected
5. washwashed twice with ice-cold water
6. customdried i.v