反应详情

To a solution of fumaric acid mono-ethyl ester (721 mg, 5 mmol) and tert-butanol (0.938 mL, 10 mmol) in 10 mL of DCM was added DMAP (122 mg, 1 mmol) followed by DCC (2.06 g, 10 mmol). The resulting mixture was stirred at rt for 16 h, taken to dryness under reduced pressure, stirred overnight with 50 mL acetone and filtered to remove DCU. The resulting filtrate was concentrated under reduced pressure, and the residue taken up in EtOAc. The EtOAc was washed twice with 30 mL 0.1 M KHSO4, and once with 30 mL saturated NaHCO3 and once with 30 mL of brine. The resulting EtOAc solution was treated with charcoal and dried over magnesium sulfate, concentrated under reduced pressure, and subjected to silica gel flash chromatography using a gradient of 0–15% EtOAc in hexanes as eluent to give essentially pure (one peak on HPLC) 4-1 (350 mg, 35% yield).

1. filtrationfiltered
2. customto remove DCU
3. concentrationThe resulting filtrate was concentrated under reduced pressure
4. washThe EtOAc was washed twice with 30 mL 0.1 M KHSO4
5. additionThe resulting EtOAc solution was treated with charcoal
6. dry with materialdried over magnesium sulfate
7. concentrationconcentrated under reduced pressure