45.7 g (0.466 mol) of 4-methylthiophene and 80 mL of carbon tetrachloride were added to a four-necked flask. 82.74 g (0.465 mol) of NBS was added in portions with stirring. The reaction was carried out at a controlled temperature, with samples taken every 2 hours for gas chromatography analysis. The reaction was stopped when the mass fraction of 4-methylthiophene was less than 1%. The mixture was filtered, and the filtrate was washed with water. The oil layer was distilled, and the fraction collected at 37-38℃/0.0004 MPa was the 3-bromo-4-methylthiophene product with a purity greater than 98% (GC) and a yield of 87%.
