Benzyl bromide (0.78 mL, 6.5 mmol, 1.0 eq.) was added slowly and dropwise to a stirred mixed solution of methyl 3,4-dihydroxybenzoate (1.1 g, 6.5 mmol, 1.0 eq.) and potassium carbonate (1.1 g, 7.8 mmol, 1.2 eq.) in N,N-dimethylformamide (11 mL). The reaction mixture was stirred overnight at room temperature. After completion of the reaction, the solvent was removed by rotary evaporator under reduced pressure. The crude product was dissolved in water and extracted with ethyl acetate, followed by adjusting the pH of the aqueous phase with 2 M hydrochloric acid to 2. The organic phase was separated and the aqueous phase was re-extracted with ethyl acetate (3×). The organic phases were combined, dried with anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using a gradient elution with 5-80% ethyl acetate/isohexane to afford methyl 4-(benzyloxy)-3-hydroxybenzoate as a white solid (0.82 g, 49% yield). NMR hydrogen spectrum (400 MHz, CDCl3) δ 7.62-7.62 (2H, m), 7.43-7.40 (5H, m), 6.94 (1H, d, J = 8.0 Hz), 5.69 (1H, s), 5.17 (2H, s), 3.88 (3H, s).
