[CH3:1][O:2][C:3](=[O:19])[CH2:4][CH2:5][C:6]([C:8]1[C:13]([CH3:14])=[CH:12][C:11]([O:15][CH3:16])=[CH:10][C:9]=1[O:17]C)=[O:7].B(Br)(Br)Br>ClCCl>[CH3:1][O:2][C:3](=[O:19])[CH2:4][CH2:5][C:6]([C:8]1[C:13]([CH3:14])=[CH:12][C:11]([O:15][CH3:16])=[CH:10][C:9]=1[OH:17])=[O:7].[CH3:1][O:2][C:3](=[O:19])[CH2:4][CH2:5][C:6]([C:8]1[C:13]([CH3:14])=[CH:12][C:11]([OH:15])=[CH:10][C:9]=1[OH:17])=[O:7]To a solution of 4-(2,4-dimethoxy-6-methyl-phenyl)-4-oxo-butyric acid methyl ester (1.0 g, 3.76 mmol) in dichloromethane (10 mL) was added 1 M BBr3 in dichloromethane (15.04 mL). The reaction mixture was stirred at room temperature for 48 hours then poured onto ice and extracted with EtOAc. The organic extracts were dried and concentrated in vacuo. The residue was dissolved in concentrated H2SO4 (0.2 mL) and MeOH (10 mL) and the mixture was heated at 75° C. for 1 hour. The mixture was concentrated in vacuo and the residue was purified by silica gel flash column chromatography to give 4-(2-hydroxy-4-methoxy-6-methyl-phenyl)-4-oxo-butyric acid methyl ester (0.300 g, 31%) and 4-(2,4-dihydroxy-6-methyl-phenyl)-4-oxo-butyric acid methyl ester (0.300 g, 34%).
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