[CH2:1]([O:3][C:4]([C:6]1[O:7][C:8]2[CH:15]=[CH:14][C:13]([Br:16])=[C:12]([OH:17])[C:9]=2[C:10]=1[CH3:11])=[O:5])[CH3:2].C(=O)([O-])[O-].[K+].[K+].Br[CH:25]([CH3:27])[CH3:26]>CN(C=O)C>[Br:16][C:13]1[CH:14]=[CH:15][C:8]2[O:7][C:6]([C:4]([O:3][CH2:1][CH3:2])=[O:5])=[C:10]([CH3:11])[C:9]=2[C:12]=1[O:17][CH:25]([CH3:27])[CH3:26]To 0.50 g (1.7 mmole) of ethyl 5-bromo-4-hydroxy-3-methyl-1-benzofuran-2-carboxylate (Example 119, Step 1) in 7 mL DMF was added 0.51 g (3.75 mmole) of potassium carbonate and 0.48 mL (3 mmole) of 2-bromopropane and the reaction was stirred at room temperature overnight. The solvent was concentrated in vacuo, and the residue was extracted with ethyl acetate and water. The organic layer washed with water and brine, dried over sodium sulfate, filtered, and concentrated to provide 0.58 g of ethyl 5-bromo-4-isopropoxy-3-methyl-1-benzofuran-2-carboxylate. Yield: 100%; m.p. 48-50° C.; MS: 341.0 (M+H)+.
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