[NH2:1][C:2]1[C:7]([CH3:8])=[C:6]([Br:9])[CH:5]=[C:4]([F:10])[C:3]=1[OH:11].C(=O)([O-])[O-].[K+].[K+].Br[CH2:19][C:20](Br)=[O:21].O>CN(C)C=O>[Br:9][C:6]1[CH:5]=[C:4]([F:10])[C:3]2[O:11][CH2:19][C:20](=[O:21])[NH:1][C:2]=2[C:7]=1[CH3:8]An ice cold suspension of 2-amino-4-bromo-6-fluoro-3-methylphenol (647 mg) and potassium carbonate (1.526 g, 11.04 mmol) in N,N-Dimethylformamide (DMF) (10 mL) was treated by dropwise addition of 2-bromoacetyl bromide (0.320 mL, 3.67 mmol). The mixture was stirred at ambient temperature for 2 hours. The mixture was treated slowly with water (10 mL+10 mL), then poured into water (50 mL) and stirred to form a suspension which was passed through a fine glass frit and dried in vacuo to give the crude product as a yellow solid. The solid was washed with cold isopropanol and dried in vacuo to provide 6-bromo-8-fluoro-5-methyl-2H-benzo[b][1,4]oxazin-3(4 H)-one (510 mg) as a light brown solid. 1H NMR (400 MHz, CHLOROFORM-d) d=7.83 (br. s., 1 H), 7.10 (d, J=9.6 Hz, 1 H), 4.65 (s, 2 H), 2.30 (s, 3 H). LC/MS (m/z) ES+=259.99 (M+1).
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