Sodium Carbonate → 1-(6-Amino-2,3-dihydro-4H-1,4-benzoxazin-4-yl)ethan-1-one

Participants

Reaction Steps

To a solution of the crude 1-(6-nitro-2H-benzo[b][1,4]oxazin-4(3H)-yl)ethanone (0.86 g, 3.89 mmol) in EtOAc (8 mL) was added SnCl2.2H2O (4.3834 g, 19.4 mmol) and the mixture was heated under reflux with stirring. After 1.5 h, the mixture was cooled to rt. To the mixture was added 2 M aqueous Na2CO3 (20 mL) followed by EtOAc (50 mL). The resulting white precipitate was filtered off and washed the white solid with EtOAc (50 mL). The filtrated was separated in a reparatory funnel. The aqueous layer was extracted with EtOAc (30 mL×1). The combined organics were washed with brine (50 mL×2), dried over Na2SO4, filtered, and concentrated under reduced pressure to give dark syrup. The dark syrup was purified by column chromatography on a silica gel column using 0 to 100% gradient of DCM-MeOH—NH4OH (89:9:1) in DCM as eluent to give 1-(6-amino-2H-benzo[b][1,4]oxazin-4(3H)-yl)ethanone as a red syrup: Mass Spectrum (ESI) m/e=193.1 (M+1).

Provenance & Evidence