2,2-difluoro-6-nitro-2H-benzo[b][1,4]oxazin-3(4H)-one → 6-amino-2,2-difluoro-2H-benzo[b][1,4]oxazin-3(4H)-one

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Reaction Steps

In a flask, 10% Pd/C (0.819 g, 0.769 mmol) was added. The flask was placed under vacuum and purged with N2 three times and then MeOH (25 mL) was added. To the flask was added a solution of 2,2-difluoro-6-nitro-2H-benzo[b][1,4]oxazin-3(4H)-one (5.90 g, 25.6 mmol, WO2008024634A1, Page 161, Intermediate C) in MeOH (20 mL). The mixture was then evacuated, purged with N2 and evacuated again. The mixture was placed under an atmosphere of H2 and stirred at rt for about 16 h. The mixture was placed under vacuum and purged with N2 three times. The mixture was filtered over a Celite Pad®, washed with MeOH (300 mL) and concentrated under reduced pressure to give 6-amino-2,2-difluoro-2H-benzo[b][1,4]oxazin-3(4H)-one (3.4 g, 66%); LC/MS (Table 2, Method c) Rt=1.42 min.; MS m/z: 201 (M+H)+.

Provenance & Evidence