反应详情

A mixture of the product from Step A (9.8 g, 40.6 mmol) and DBU (9 mL, 60 mmol) in DCM (70 mL) was stirred at rt overnight. The mixture was cooled to 0° C. and washed with 1N HCl aqueous solution and brine, dried over Na2SO4. Evaporation and purification by column chromatography (eluent: 20% EtOAc in hexanes to 40%) gave the product as a white solid. 1H-NMR (400 MHz, CDCl3): δ 1.44 (s, 9H), 2.36-2.47 (m, 2H), 2.88-2.99 (m, 2H), 3.74 (s, 3H), 4.36 (br s, 1H), 4.71 (br s, 1H), 6.71-6.72 (m, 1H). LC/MS: C12H19NO4: m/z 264.0 (M+Na).

1. temperatureThe mixture was cooled to 0° C.
2. washwashed with 1N HCl aqueous solution and brine
3. dry with materialdried over Na2SO4
4. customEvaporation and purification by column chromatography (eluent: 20% EtOAc in hexanes to 40%)