反应详情

温度

-10 °C

L-Asparagine monohydrate 1* (37.5 g, 0.25 mol) was dissolved in 3M H2SO4 (330 ml) and treated with KBr (39.3 g, 0.75 mol). The solution was stirred and cooled in an ice-MeOH bath to ca. -10° C. Some precipitation occurred. A solution of NaNO2 (21.6 g, 0.31 mol) in H2O (38 ml) was added dropwise over 80 minutes. The internal temperature was kept at -10° to -5° during the addition and for 90 minutes afterward. The mixture was filtered and the solid portion washed with ice cold H2O (3x) and dried overnight to give the product 2* (31.64 g, 65%) as an off-white solid: [α]D =-67.8° (C 4.51, EtOH). ##STR93##

1. customSome precipitation
2. additionThe internal temperature was kept at -10° to -5° during the addition and for 90 minutes afterward
3. filtrationThe mixture was filtered
4. washthe solid portion washed with ice cold H2O (3x)
5. customdried overnight
6. customto give the product 2* (31.64 g, 65%) as an off-white solid