[F:1][C:2]1[CH:3]=[CH:4][C:5]([N+:14]([O-])=O)=[C:6]([CH:13]=1)[O:7][CH2:8][C:9](OC)=[O:10]>[Pd].CCO>[F:1][C:2]1[CH:3]=[CH:4][C:5]2[NH:14][C:9](=[O:10])[CH2:8][O:7][C:6]=2[CH:13]=1To 500 mg of 5% Pd/C in a Parr bottle was added 100 ml of EtOH followed by 5.0 g (21.8 mmol) of methyl 5-fluoro-2-nitrophenoxyacetate. The flask was placed in a Parr Apparatus, evacuated and then charged with hydrogen. The suspension was then shaken for 2 hours. After evacuating the flask and recharging with nitrogen, the solids were removed by vacuum filtration through Celite®. Since some product does precipitate, the filter cake is repeatedly rinsed with EtOAc (200 ml). The filtrate is refluxed for 4 hours and then evaporated to dryness in vacuo to give the desired material, 7-fluoro-2H-1,4-benzoxazin-3(4H)-one, as a white solid (m.p. 201°-202° C.) in quantitative yield.
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