41110-33-2

193966-70-0

Methyl 5-methylpyrazine-2-carboxylate (0.5 g, 3.28 mmol) was dissolved in acetic acid (5 mL) at room temperature and bromine (0.9 mL, 3.6 mmol) was added slowly. The reaction mixture was heated to 80 °C and kept for 45 min. Upon completion of the reaction, it was concentrated under reduced pressure to remove the acetic acid. The residue was adjusted to basicity with saturated sodium bicarbonate solution and subsequently extracted with ethyl acetate. The organic layers were combined, dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography to afford methyl 5-bromomethylpyrazine-2-carboxylate (0.3 g, 40% yield) as a brown liquid using hexane solution of 20% ethyl acetate as eluent. Mass spectrometry analysis (ESI): calculated value [M+H]+ 230.97, measured value [M+H]+ 231.0.