反应详情

To a solution of (R)-2-((tert-butoxycarbonyl)amino)-3-mercapto-3-methylbutanoic acid (4.5 g, 18.05 mmol) in THF (60 mL) was added a solution of methyl 2-bromoacetate (3.04 g, 19.85 mmol) in THF (10 mL) followed by DIPEA (9.46 mL, 54.1 mmol). The resulting mixture was stirred at rt for 4.5 h. The reaction mixture was concentrated in vacuo to remove most of the solvent, and the residue was diluted with EtOAc and sat. aq. NaHCO3 solution. The aqueous layer was acidified with 1N HCl solution to adjust the pH to 2-3. The resulting aqueous layer was extracted with EtOAc (2×). The organic layers were combined and dried over MgSO4. The filtrate was concentrated in vacuo to give the title compound as solid (4.8 g, 83%). 1H NMR (400 MHz, DMSO-d6) δ 6.93 (d, J=9.0 Hz, 1H), 4.10 (d, J=9.5 Hz, 1H), 3.62 (s, 3H), 3.41 (s, 2H), 1.39 (s, 9H), 1.33 (s, 3H), 1.27 (s, 3H); MS (ESI+) m/z 266.0 (M-55)+.

1. concentrationThe reaction mixture was concentrated in vacuo
2. customto remove most of the solvent
3. additionthe residue was diluted with EtOAc and sat. aq. NaHCO3 solution
4. extractionThe resulting aqueous layer was extracted with EtOAc (2×)
5. dry with materialdried over MgSO4
6. concentrationThe filtrate was concentrated in vacuo