反应详情

To a mixture of 45% aqueous KOH (30 mL, 2.70 mmol) and Et2O (100 mL) at about 0° C. 1-methyl-3-nitro-1-nitrosoguanidine (5.0 g, 34 mmol, TCI) was added portion-wise. After about 30 min the layers were separated and the organic layer was added slowly to a solution of (R)-(9H-fluoren-9-yl)methyl 3-(chlorocarbonyl)piperidine-1-carboxylate (1.0 g, 2.7 mmol) prepared using W from (R)-1-(((9H-fluoren-9-yl)methoxy)carbonyl)piperidine-3-carboxylic acid (Fluka) in THF (10 mL). The reaction mixture was slowly stirred for about 30 min at about 0° C. before the drop-wise addition of 48% aqueous HBr (2.0 mL, 37 mmol). After about 15 min, the reaction mixture was washed with brine (2×100 mL). The organic layer was dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure to give (R)-(9H-fluoren-9-yl)methyl 3-(2-bromoacetyl)piperidine-1-carboxylate (1.10 g, 95%) as a clear oil: LC/MS (Table 2, Method a) Rt=2.59 min; MS m/z: 428/430 (M+H)+.

1. customAfter about 30 min the layers were separated
2. customprepared
3. washthe reaction mixture was washed with brine (2×100 mL)
4. dry with materialThe organic layer was dried over anhydrous Na2SO4
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure