反应详情

Methyl iodide (1.01 mL, 16.3 mmol) was added dropwise to a solution of (2S)-5-(benzyloxy)-2-{[(tert-butoxy)carbonyl]amino}-5-oxopentanoic acid XII (5.00 g, 14.82 mmol) and K2CO3 (2.25 g, 16.3 mmol) in DMF (25 mL) at room temperature The reaction mixture was stirred about 3 h at room temperature before adding additional methyl iodide (1.01 mL, 16.3 mmol). EtOAc was then added to the reaction and washed 3×10% Na2S2O3 and dried over MgSO4. The solvent was removed under reduced pressure and the crude product was purified on a silica gel column (100:1 and then 50:1 CHCl3/MeOH) to give 5-benzyl 1-methyl (2S)-2-{[(tert-butoxy)carbonyl]amino}pentanedioate XIII (4.20 g, 12.23 mmol, 82% yield). ESIMS found for C18H25NO6 m/z 352 (M+H).

1. washwashed 3×10% Na2S2O3
2. dry with materialdried over MgSO4
3. customThe solvent was removed under reduced pressure
4. customthe crude product was purified on a silica gel column (100:1