Br[C:2]1[N:3]=[CH:4][NH:5][CH:6]=1.[C:7]([Li])(C)([CH3:9])[CH3:8].[CH:12]([C:14]1[CH:26]=[CH:25][C:24]2[C:16](=[CH:17][C:18]3[CH2:22][CH2:21][O:20][C:19]=3[CH:23]=2)[CH:15]=1)=[O:13].[Cl-].[NH4+]>C1COCC1.CCCCC>[CH2:22]1[CH2:21][O:20][C:19]2[CH:23]=[CH:24][C:25]3[C:17]([C:18]1=2)=[CH:16][CH:15]=[C:14]([C:12]([C:2]1[N:3]=[CH:4][NH:5][CH:6]=1)([OH:13])[CH:7]([CH3:9])[CH3:8])[CH:26]=3A solution of 4-bromo-1H-imidazole (2.11 g) in THF (40 ml) was cooled to −78° C. A solution of tert-butyllithium in pentane (1.7 M; 13 ml) was added to the solution. The mixture was stirred at 5° C. for 2 h and then cooled to −78° C. 6-formyl-2,3-dihydronaphtho[2,3-b]furane (1.46 g) in THF (30 ml) was added to the mixture. The mixture was allowed to room temperature and was stirred for 20 h. Ammonium chloride solution was added to the mixture and extracted with mixed solution of THF and ethyl acetate. The organic layer was dried and concentrated. The residue was purified by silica gel chromatography to give the titled compound (1.01 g) as a colorless solid.
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