The general procedure for the synthesis of ethyl 2-bromo-2-(p-fluorophenyl)acetate from ethyl (4-fluorophenyl)acetate was as follows: to a solution of ethyl (4-fluorophenyl)acetate (61.0 g, 333 mmol) in carbon tetrachloride (300 mL) was added N-bromosuccinimide (61 g, 343 mmol) and hydrobromic acid (4 drops, 48% aqueous solution) in turn, and the reaction The mixture was heated to reflux for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered and the filtrate was concentrated under reduced pressure to obtain the crude product α-bromo(4-fluorophenyl)ethyl acetate (68 g, 78% yield). The above crude product (68.00 g, 260.0 mmol) was dissolved in N,N-dimethylformamide (300 mL), 4-nitroimidazole (35.0 g, 312 mmol) and potassium carbonate (108.0 g, 780.0 mmol) were added, and the reaction was stirred for 18 hours at room temperature. The reaction mixture was filtered and the filtrate was concentrated under reduced pressure. The concentrated crude product was dissolved in ethyl acetate and washed sequentially with saturated sodium bicarbonate solution and brine. The organic layer was dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure. Purification by fast column chromatography (silica gel 400 g, gradient elution with ethyl acetate/hexane) afforded the target product ethyl 2-bromo-2-(p-fluorophenyl)acetate (39.8 g, 52% yield) as a light orange oil. The product was confirmed to be structurally correct by 1H NMR (300 MHz, CDCl3). The results of elemental analysis (calculated value C13H12FN3O4: C 53.24%, H 4.12%, N 14.33%; measured value: C 53.51%, H 4.07%, N 14.43%) were consistent with the theoretical values. Mass spectrometry (FDMS) showed a molecular ion peak (M+) of 294.
