[Br:1][C:2]1[CH:3]=[C:4]([N+:12]([O-:14])=[O:13])[C:5]([CH3:11])=[C:6]([CH:10]=1)[C:7]([OH:9])=[O:8].[C:15](=O)([O-])[O-].[Na+].[Na+].CI>CN(C=O)C>[Br:1][C:2]1[CH:3]=[C:4]([N+:12]([O-:14])=[O:13])[C:5]([CH3:11])=[C:6]([CH:10]=1)[C:7]([O:9][CH3:15])=[O:8]To a stirred solution of 5-bromo-2-methyl-3-nitrobenzoic acid (285 g, 1105 mmol) in DMF (2.8 L) at room temperature was added sodium carbonate (468 g, 4415 mmol) followed by addition of methyl iodide (626.6 g, 4415 mmol). The resulting reaction mixture was heated at 60° C. for 8 h. After completion (monitored by TLC), the reaction mixture was filtered (to remove sodium carbonate) and washed with ethyl acetate (1 L×3). The combined filtrate was washed with water (3 L×5) and the aqueous phase was back extracted with ethyl acetate (1 L×3). The combined organic layers were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to afford the title compound as a solid (290 g, 97% yield). The isolated compound was taken directly into the next step. 1H NMR (CDCl3, 400 MHz) δ 8.17 (s, 1H), 7.91 (s, 1H), 3.96 (s, 3H), 2.59 (s, 3H).
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