20274-69-5

15017-52-4

General procedure for the synthesis of 4-fluoro-3-nitrobenzyl bromide from 3-nitro-4-fluorobenzyl alcohol: 1. in a dry reaction flask, phosphorus tribromide (1.13 mL) was slowly added dropwise to a solution of 4-fluoro-3-nitrobenzyl alcohol (2.1 g, 11.23 mmol) in anhydrous ether (40 mL). 2. Stir the reaction mixture at room temperature for 1 hour until the reaction is complete. 3. After the reaction is complete, carefully add water to the reaction mixture to quench the reaction. 4. The reaction mixture was extracted with ethyl acetate (3 × 20 mL) and the organic phases were combined. 5. The organic phase was washed sequentially with saturated sodium bicarbonate solution (20 mL) and saturated brine (20 mL). 6. The organic phase was dried with anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to obtain the crude product. 7. The crude product was purified by silica gel column chromatography (eluent: petroleum ether/ethyl acetate, gradient elution) to obtain 4-fluoro-3-nitrobenzyl bromide (2.50 g, 95% yield) as a light yellow solid. Product Characterization: 1H NMR (270 MHz, CDCl3) δ (ppm): 8.10 (dd, 1H, J = 7.1, 2.2 Hz), 7.67 (m, 1H), 7.29 (dd, 1H, J = 10.7, 8.6 Hz), 4.49 (s, 2H).