Methanol → 1,3-Difluoro-2,4-dimethoxy-5-nitrobenzene

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Reaction Steps

Sodium methoxide (1.0M) is prepared by adding freshly cut sodium metal (rinsed with toluene) portionwise to anhydrous methanol (Aldrich Chemical Co.) under nitrogen in flame-dried glassware with stirring; an ice-water bath is used to control the reaction temperature. To 9.8 g (50 mmol) of 2,3,4,5-tetrafluoronitrobenzene (Aldrich) under nitrogen at room temperature in flame-dried glassware is added sodium methoxide solution (2.2 equivalents) via syringe over the course of 5-10 minutes, with stirring. The resulting reaction mixture is stirred at room temperature, while monitoring the progress of the reaction by thin layer chromatography (TLC). Additional sodium methoxide solution is added as necessary. Once the reaction reaches completion (1-24 hours), several drops of 1M citric acid are added, and the reaction mixture is partitioned between ether and water. The aqueous layer is extracted once with ether. The combined organic portions are washed once with brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to give Compound 1 as 10.92 g (99%) of a pale yellow solid: m.p. 32.0°-32.5° C.; 1H NMR (CDCl3) 7.52 (dd, 1H), 4.12 (s, 3H), 4.04 (s, 3H); 19F NMR (CDCl3) 132.0 (m, 1F), 141.9 (d, 1F). Anal. calc. for C8H7NO4F2 : C, 43.85; H, 3.22; N, 6.39. Found: C, 43.84; H, 3.15; N, 6.15.

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