反应详情

To a solution of intermediate 57 (9.7 g, 32.2 mmol) in methanol (400 mL) was added chlorotrimethylsilane (3 mL) to achieve pH=2. The reaction mixture was heated at strong reflux for 72 h, during which time the pH was monitored and more chlorotrimethylsilane added as necessary to maintain an acidic solution. The reaction mixture was allowed to cool and was then concentrated on a rotary evaporator. The residue was purified by column chromatography (silica gel, 7:2:1 hexanes/dichloromethane/methanol) to afford the crude ester as a yellow solid (9.0 g, 89%). ESI-MS m/e 280.1 (M+1).

1. temperatureThe reaction mixture was heated
2. temperatureat strong reflux for 72 h, during which time the pH
3. temperatureto maintain an acidic solution
4. temperatureto cool
5. concentrationwas then concentrated on a rotary evaporator
6. customThe residue was purified by column chromatography (silica gel, 7:2:1 hexanes/dichloromethane/methanol)