Methanol → 2-Fluoro-3-(4-trifluoromethyl-benzenesulfonylamino)-benzoic acid methyl ester

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Reaction Steps

To 2-fluoro-3-(4-trifluoromethyl-benzenesulfonylamino)-benzoic acid (31, 4.0 g, 11 mmol) in 40 mL of methanol, sulfuric acid (8.8 mL, 0.16 mol) was added and the reaction mixture was refluxed overnight. The resulting reaction mixture was concentrated under vacuum, and the residue was combined with 5% aqueous sodium bicarbonate solution and extracted with ethyl acetate. The organic layer was washed with brine, dried over anhydrous sodium sulfate, and filtered. The filtrate was concentrated under vacuum and purified by silica gel column chromatography eluting with 20% ethyl acetate in hexane. Appropriate fractions were combined and concentrated under vacuum to provide the desired compound (32, 3.35 g, 81%). MS(ESI) [M−H+]−=376.4.

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