6-Bromo-5-methoxy-2h-3,1-benzoxazine-2,4(1h)-dione → Methyl 6-amino-3-bromo-2-methoxybenzoate

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Reaction Steps

A solution of Example 385B (6.83 g, 25.2 mmol) in anhydrous methanol (300 mL) was refluxed for 48 hours. The solution was concentrated and the residue was purified by chromatography on a silica gel column eluting with 20% ethyl acetate/hexane to give the desired product 5.7 g, 87.2% yield. 1H NMR (DMSO-d6) δ 3.70 (s, 3H), 3.82 (s, 3H), 5.92 (s, 2H), 6.45 (d, 1H), 7.30 (d, 1H); MS (ESI(−)) m/e 258, 260 (M−H)−.

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