546-88-3

105942-08-3

177995-39-0

Step A: 6-Bromobenzo[d]isoxazol-3-amine (1.13 g, 15.0 mmol) and N-hydroxyacetamide were dissolved in N,N-dimethylformamide (DMF, 20 mL). Potassium tert-butoxide (KOt-Bu, 1.68 g, 15.0 mmol) was added to the reaction system and stirred at room temperature for 30 min. Subsequently, 4-bromo-2-fluorobenzonitrile (2.0 g, 10.0 mmol) was added and the reaction was continued at room temperature for 2 hours. After completion of the reaction, the reaction mixture was diluted with ethyl acetate (50 mL) and water (50 mL). The aqueous layer was separated and extracted with ethyl acetate. The organic phases were combined, washed with water, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The crude product was purified by fast column chromatography using ethyl acetate/hexane (1:4, v/v) and ethyl acetate/hexane (1:3, v/v) sequentially as eluent to afford the target compound 3-amino-6-bromobenzo[D]isoxazole (1.35 g, 63% yield). Mass spectra (APCI) m/z: 215.2, 217.1 ([M+H]+).