Step B: Ethyl 2-(bromomethyl)-4-methoxybenzoate was synthesized as an intermediate; ethyl 4-methoxy-2-methylbenzoate (2.24 g, 11.5 mmol) was dissolved in carbon tetrachloride (20 mL) and placed in an oil bath and heated to 78 °C. Subsequently, N-bromosuccinimide (2.26 g, 12.6 mmol) was added to the reaction system. Benzoyl peroxide (0.28 g, 1.15 mmol) was added in batches over 4 hours. The reaction mixture was stirred continuously at 78 °C overnight. After completion of the reaction, the mixture was cooled to room temperature and filtered to remove insoluble solids. The filtrate was concentrated under reduced pressure and purified by fast column chromatography (silica gel, eluent ratio of 1:50 ethyl acetate/hexanes) to afford the target product ethyl 2-(bromomethyl)-4-methoxybenzoate (1.60 g, 52% yield) as a clear oil.1H NMR (300 MHz, CDCl3) δ 7.99 (d, J = 8.7 Hz, 1H) 6.96 (s, 1H), 6.86 (dd, J = 8.7, 2.6 Hz, 1H), 4.96 (s, 2H), 4.37 (q, J = 7.1 Hz, 2H), 3.86 (s, 3H), 1.41 (t, J = 7.1 Hz, 3H); ESI MS m/z 273 [M + H]+.
