Cl[C:2]([F:9])([F:8])C(OCC)=O.[Br:10][C:11]1[CH:12]=[C:13]([CH:18]=[CH:19][C:20]=1[OH:21])[C:14]([O:16][CH3:17])=[O:15].C(=O)([O-])[O-].[K+].[K+].O>CN(C)C=O>[Br:10][C:11]1[CH:12]=[C:13]([CH:18]=[CH:19][C:20]=1[O:21][CH:2]([F:9])[F:8])[C:14]([O:16][CH3:17])=[O:15]Ethyl chlorodifluoroacetate (1.12 ml, 8.7 mmol) was added to a mixture of methyl 3-bromo-4-hydroxybenzoate (Description 64, 2.0 g, 8.7 mmol) and potassium carbonate (1.2 g, 8.7 mmol) in N,N-dimethylformamide (20 ml) and the mixture was heated at 65° C. for 16 h. The mixture was cooled, water (100 ml) was added and the mixture was extracted with ethyl acetate (2×100 ml). The combined organic fractions were dried (Na2SO4) and the solvent was evaporated under reduced pressure. The residue was purified by column chromatography on silica gel, eluting with hexane/EtOAc (95:5) to give the title compound as a colorless solid (1.20 g, 49%). 1H NMR (250 MHz, CDCl3) δ8.31 (1 H, d, J 2.0 Hz), 8.22 (1 H, dd, J 8.5, 2.0 Hz), 7.05 (1 H, m), 6.61 (1 H, t, J 73 Hz), and 3.93 (3 H, s).
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