Boron tribromide → (S)-5-amino-2'-bromo-4'-fluoro-2,6-dihydrospiro[[1,4]oxazine-3,9'-xanthen]-7'-ol

Participants

Reaction Conditions

Reaction Steps

In a 50-mL flask, the (S)-2′-bromo-4′-fluoro-7′-methoxy-2,6-dihydrospiro[[1,4]oxazine-3,9′-xanthen]-5-amine (0.340 g, 0.864 mmol) was taken up in DCM (15 mL). The suspension was cooled to 0° C., and a DCM solution of boron tribromide (2.59 mL, 2.59 mmol) was added. After 1 h, the reaction was quenched with 18 mL of saturated aqueous NH4Cl and 2 mL of aqueous NH4OH. The mixture was diluted further with water (10 mL), and the aqueous phase was extracted with 5% MeOH-DCM (3×50 mL). The organics were combined, washed with dilute brine (15 mL), dried over sodium sulfate and concentrated to afford 241 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.

Provenance & Evidence