2160-62-5

2160-63-6

2160-62-5

General procedure for the synthesis of 5-bromothiophene-2-carboxaldehyde oxime from 5-bromothiophene-2-carbonitrile: To a mixture of 5-bromothiophene-2-carboxaldehyde oxime (1.3 g, 6.2 mmol) and tetrahydrofuran (15 mL), acetic acid (1.4 mL, 25 mmol) and acetic anhydride (1.5 mL, 15 mmol) were added, and the reaction was started at room temperature. Subsequently, the reaction mixture was stirred at 50 °C for 2 hours, then warmed to 70 °C to continue stirring for 8 hours. Upon completion of the reaction, the reaction mixture was cooled and the solvent was removed by vacuum concentration. The crude product was purified by NH-silica gel column chromatography (eluent ratio heptane:ethyl acetate=8:1) to afford 5-bromothiophene-2-carbonitrile (1.0 g, 5.4 mmol, 88% yield) as a colorless solid.1H-NMR (CDCl3) δ (ppm): 7.11 (1H, d, J=4.0 Hz), 7.40 (1H, d, J=4.0 Hz).