反应详情

To (S)-2-(tert-butoxycarbonylamino)-5-(dimethylamino)pentanoic acid (129 mmol, 1.0 eq) in MeOH (130 mL) under N2 (g) at 0° C. was added TMSCHN2 (84 mL, 168 mmol, 1.3 eq, 2.0 M in diethyl ether) slowly via addition funnel over 40 minutes. The ice-water bath was removed and the reaction mixture was warmed to room temperature and stirred 16 h. The volatiles were removed in vacuo and the residue was partitioned between EtOAc (250 mL) and satd NaHCO3 (200 mL). Additional H2O was added to form a clear aqueous layer, which was extracted with EtOAc (2×175 mL). The combined extracts were then washed with additional satd NaHCO3 (100 mL) and brine, dried over MgSO4, filtered and concentrated to afford (S)-methyl 2-(tert-butoxycarbonylamino)-5-(dimethylamino)pentanoate (16.8 g, 47%) as a yellow oil. 1H NMR (400 MHz, CDCl3) δ 5.85 (d, J=6.8 Hz, 1H), 4.15-4.04 (m, 1H), 3.58 (s, 3H), 2.12 (t, J=6.9 Hz, 2H), 2.06 (s, 6H), 1.73-1.51 (m, 4H), 1.29 (s, 9H); MS (EI) m/z 275 (MH+).

1. additionslowly via addition funnel over 40 minutes
2. customThe ice-water bath was removed
3. customThe volatiles were removed in vacuo
4. customthe residue was partitioned between EtOAc (250 mL) and satd NaHCO3 (200 mL)
5. additionAdditional H2O was added
6. customto form a clear aqueous layer, which
7. extractionwas extracted with EtOAc (2×175 mL)
8. washThe combined extracts were then washed with additional satd NaHCO3 (100 mL) and brine
9. dry with materialdried over MgSO4
10. filtrationfiltered
11. concentrationconcentrated