[OH:1][C:2]1[CH:3]=[C:4]([CH:7]=[CH:8][C:9]=1[OH:10])[CH:5]=[O:6].[CH3:11][O:12][CH2:13][CH2:14]Br.C(=O)([O-])[O-].[Na+].[Na+]>CN(C=O)C>[OH:1][C:2]1[CH:3]=[C:4]([CH:7]=[CH:8][C:9]=1[O:10][CH2:14][CH2:13][O:12][CH3:11])[CH:5]=[O:6]An amount of 3,4-dihydroxybenzaldehyde (5.0 g, 36.2 mmol) in 20 mL of N,N′-dimethylformamide is added 2-bromoethyl methyl ether (3.4 mL, 36.2 mmol), and sodium carbonate (5.0 g, 72.4 mmol). The reaction mixture is stirred at room temperature for 3 days. After removal solids by filtration, the solution is subsequently evaporated under high-pressure vacuum to dark brown liquid. The residue is added water and acidified with 12 N HCl solution to pH˜2, then extracted 4×100 mL of EtOAc. The combined organic layer is washed with brine, dried over Mg2SO4, stirred in darko, filtered and evaporated to give yellow liquid. Purification is performed by column chromatography over silica gel using 40% EtOAc/Hex as eluent to give 2.13 g of colorless solid: mp 74-75° C.; MS (ESI) m/z 195.1 (M+H)−1
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