[F:1][C:2]1[CH:3]=[C:4]([CH:8]=[C:9]([CH3:11])[CH:10]=1)[C:5]([OH:7])=[O:6].[C:12](=O)([O-])[O-].[K+].[K+].CI>CC(C)=O>[F:1][C:2]1[CH:3]=[C:4]([CH:8]=[C:9]([CH3:11])[CH:10]=1)[C:5]([O:7][CH3:12])=[O:6]To a solution of 3-fluoro-5-methylbenzoic acid (1.50 g, 9.73 mmol, Oakwood) in Acetone (40 mL) was added Potassium carbonate (1.34 g, 9.73 mmol) followed by Methyl iodide (0.73 mL, 12 mmol). The reaction mixture was heated to 65° C. for 1 hour, heating discontinued and stirred overnight, then heating resumed at that temperature for a further 2 hours. Additional Methyl iodide (0.5 mL, 8 mmol) was added and heating was continued for 6 hours. Solids were removed by filtration and acetone was removed in vacuo. The residue was partitioned between 1N NaOH and ethyl acetate. The aqueous portion was extracted with a further two portions of ethyl acetate. The combined extracts were washed with brine, then dried over sodium sulfate, decanted and concentrated. The product so obtained was used without further purification (1.64 g, 100%). 1H NMR (300 MHz, CDCl3): δ 7.66-7.63 (m, 1H), 7.51 (d, 1H), 7.10-7.04 (m, 1H), 3.91 (s, 3H), 2.40 (s, 3H).
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