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

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Reaction Conditions

Reaction Steps

In a 100-mL flask, (S)-2′-bromo-4′-fluoro-7′-methoxy-2,6-dihydrospiro[[1,4]oxazine-3,9′-xanthen]-5-amine (0.233 g, 0.593 mmol) was dissolved in DCM (7.5 mL). The solution was cooled to 0° C., and a DCM solution of boron tribromide (1 M, 1.78 mL, 1.78 mmol) was added. The mixture was stirred at 0° C. for 1 h, then was quenched with saturated aqueous NH4Cl (18 mL) and aqueous NH4OH (2 mL). The aqueous phase was extracted 5% MeOH-DCM (3×40 mL). The organics were combined, washed with dilute brine (15 mL), dried over sodium sulfate and concentrated to afford 187 mg of (S)-5-amino-2′-bromo-4′-fluoro-2,6-dihydrospiro[[1,4]oxazine-3,9′-xanthen]-7′-ol.

Provenance & Evidence