反应详情

To a solution of Intermediate 75a (739 mg, 1.811 mmol) in EtOAc (9 mL) and 1N sodium hydroxide solution (4.5 mL, 4.53 mmol) was added 2,2,2-trichloroethyl chloroformate (341 μL, 2.54 mmol), and the mixture stirred vigorously at RT for 1 h. The aqueous layer was extracted with EtOAc (2×20 mL), and then the combined organics dried and concentrated in vacuo. The residue was purified by FCC, using 0-10% MeOH in DCM, to give the title compound (743 mg, 70%). LCMS (Method 4): Rt 4.69 min, m/z 582, 584, 586 [MH+].

1. extractionThe aqueous layer was extracted with EtOAc (2×20 mL)
2. customthe combined organics dried
3. concentrationconcentrated in vacuo
4. customThe residue was purified by FCC