反应详情

温度

0 °C

Into an ice-cooled solution of methyl ester from Step C (2.99 g, 8.54 mmol) in THF (50 mL) was added an aqueous LiOH solution (1N, 50 mL) and stirred at 0° C. Upon consumption of the starting materials, the organic solvents were removed and the aqueous phase was neutralized with cooled 1N HCl at 0° C., and extracted with EtOAc, and dried over Na2SO4 overnight. Filtration and evaporation to dryness led to the title acid (S)-2-tert-butoxycarbonylamino-3-(4-carbamoyl-2,6-dimethylphenyl)propionic acid (2.51 g, 87%); 1H NMR (300 MHz, DMSO-d6): δ 1.30 (9H, s), 2.32 (6H, s), 2.95 (1H, dd, J=8.8, 13.9 Hz), 3.10 (1H, dd, J=6.2, 14.0 Hz), 4.02-4.12 (1H, m), 7.18-7.23 (2H, m), 7.48 (2H, s), 7.80 (1H, s); MS (ES+) (relative intensity): 236.9 (6) (M−Boc)+.

1. customUpon consumption of the starting materials
2. customthe organic solvents were removed
3. temperaturewith cooled 1N HCl at 0° C.
4. extractionextracted with EtOAc
5. dry with materialdried over Na2SO4 overnight
6. filtrationFiltration and evaporation to dryness