反应详情

温度

0 °C

In a 500-mL flask, (S)-2′-bromo-4′-fluoro-7′-methoxy-2,6-dihydrospiro[[1,4]oxazine-3,9′-xanthen]-5-amine (0.676 g, 1.719 mmol) was suspended in DCM (50 mL). The suspension was cooled to 0° C., and boron tribromide (1.0 M in DCM; 5.16 mL, 5.16 mmol) was added. After 1.5 h, excess boron tribromide was quenched with saturated aqueous NH4Cl (18 mL) and aqueous NH4OH (2 mL). The aqueous phase was separated and extracted further with 5% MeOH-DCM (3×50 mL). The organics were combined, washed with brine (15 mL), dried over sodium sulfate and concentrated to afford 604 mg of (S)-5-amino-2′-bromo-4′-fluoro-2,6-dihydrospiro[[1,4]oxazine-3,9′-xanthen]-7′-ol which was used in the next step without further purification.

1. customexcess boron tribromide was quenched with saturated aqueous NH4Cl (18 mL) and aqueous NH4OH (2 mL)
2. customThe aqueous phase was separated
3. extractionextracted further with 5% MeOH-DCM (3×50 mL)
4. washwashed with brine (15 mL)
5. dry with materialdried over sodium sulfate
6. concentrationconcentrated