反应详情

To a round bottom flask was added (R)-2-amino-3-mercapto-3-methylbutanoic acid (5.06 g, 33.9 mmol), N-(benzyloxycarbonyloxy)succinimide (8.87 g, 35.6 mmol), MeOH (50 mL) followed by DIPEA (11.9 mL, 67.8 mmol). The reaction was stirred at rt for 1 hr. The reaction was concentrated and the residue was diluted with EtOAc (120 mL). The organics was washed with water (2×50 mL) and saturated aqueous NaCl (50 mL). The organic layer was separated, dried over MgSO4, filtered and concentrated to give (R)-2-(benzyloxycarbonylamino)-3-mercapto-3-methylbutanoic acid (4.78 g, 16.9 mmol, 49.7% yield) as a clear oil. Anal. Calcd. for C13H17NO4S m/z 283.3. found: 282.3 (M−H)+; 1H NMR (500 MHz, CDCl3) δ ppm 7.45-7.30 (m, 5H), 6.09-5.84 (m, 1H), 5.20-5.01 (m, 2H), 4.37-4.18 (m, 1H), 1.53 (br. s., 3H), 1.39 (br. s., 3H); 13C NMR (126 MHz, CDCl3) δ ppm 156.43, 136.49, 128.44, 128.28, 128.02, 53.12, 41.51, 30.83, 29.72, 11.64.

1. concentrationThe reaction was concentrated
2. additionthe residue was diluted with EtOAc (120 mL)
3. washThe organics was washed with water (2×50 mL) and saturated aqueous NaCl (50 mL)
4. customThe organic layer was separated
5. dry with materialdried over MgSO4
6. filtrationfiltered
7. concentrationconcentrated