The reaction was carried out in the presence of N,N-dimethylformamide (10 mL) and potassium carbonate (2.76 g, 20 mmol) in the presence of N,N-dimethylformamide (10 mL) and potassium carbonate (2.76 g, 20 mmol) with stirring for 3 h at 60 °C using 3-bromocatechol (1.88 g, 10 mmol) and diiodomethane (5.4 g, 20 mmol). After completion of the reaction, the reaction was quenched with water (50 mL) and extracted with ethyl acetate (100 mL x 5). The organic phases were combined and concentrated under reduced pressure, and the resulting residue was purified by silica gel thin layer preparative chromatography (unfolding agent: petroleum ether) to afford the target product 4-bromo-1,3-benzodioxazole (1.46 g, 73% yield). The product was characterized by 1H-NMR (400 MHz, CDCl3) with chemical shifts δ: 6.97 (d, J = 8 Hz, 1H), 6.77 (d, J = 8 Hz, 1H), 6.71 (d, J = 8 Hz, 1H), 6.03 (s, 2H) ppm.
