5'-ブロモ-2'-フルオロアセトフェノン

製造方法Synthesis of 1-(5-Bromo-2-fluorophenyl)ethanone: In a dry flask, a solution of 5-bromo-2-fluoro-N-methoxy-N-methylbenzamide (3.73 g, 14.2 mmol) in tetrahydrofuran (24 mL) was treated dropwise with a solution of methyl magnesium chloride (3 M in THF, 5.69 mL, 17 mmol) at 12–16 °C. After complete addition, the reaction mixture was heated to reflux. After 20 min, the resulting white suspension was quenched with saturated ammonium chloride solution (25 mL) under ice cooling. The mixture was then diluted with ethyl acetate (50 mL), and the aqueous layer was separated and re-extracted with ethyl acetate (50 mL). The combined organic layers were washed with brine (20 mL), dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The crude product was purified to afford 1-(5-bromo-2-fluorophenyl)ethanone as a pale yellow solid (2.6 g, 84% yield), with an Rf = 0.55 (silica gel, eluent: heptane/ethyl acetate = 4:1).