[I:1][C:2]1[CH:10]=[CH:9][C:8]([OH:11])=[CH:7][C:3]=1[C:4]([OH:6])=[O:5].[C:12](=[O:15])([O-])[O-].[Cs+].[Cs+].[CH3:18][O:19][C:20]1[CH:27]=[CH:26][C:23]([CH2:24]Cl)=[CH:22][CH:21]=1.C([O-])(O)=O.[Na+]>C(#N)C>[CH3:18][O:19][C:20]1[CH:27]=[CH:26][C:23]([CH2:24][O:5][C:4](=[O:6])[C:3]2[CH:7]=[C:8]([O:11][CH2:4][C:3]3[CH:7]=[CH:8][C:9]([O:15][CH3:12])=[CH:10][CH:2]=3)[CH:9]=[CH:10][C:2]=2[I:1])=[CH:22][CH:21]=1To a stirred solution of 2-iodo-5-hydroxybenzoic acid (prepared according to the method described in J. Am. Chem. Soc., 1984, 106, 2651) (27.15 g, 103 mmol) in anhydrous acetonitrile (400 mL) was added cesium carbonate (73.80 g, 227 mmol) and 4-methoxybenzyl chloride (33.5 mL, 247 mmol). The resulting solid mass was broken up and the mixture heated at 65° C. for 15 h. The reaction mixture was poured into sat. NaHCO3 (aq.) (400 mL) and the resultant mixture extracted with ethyl acetate (3×300 mL). The combined organic extracts were washed with brine (300 mL), dried (MgSO4) and concentrated in vacuo. The crude product was purified by chromatography on silica gel with a gradient of ethyl acetate:hexanes (1:9, v/v) to ethyl acetate:hexanes (1:3, v/v) as eluent to afford 2-iodo-5-(4-methoxybenzyloxy)benzoic acid 4-methoxybenzyl ester (15.39 g, 30.52 mmol, 30%).
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