Sodium hydride (1.2 g, 60% oil solution, 30 mmol) was slowly added to a solvent mixture of methanol (6 mL) and dimethylsulfoxide (12 mL) and stirred at room temperature for 30 minutes. Subsequently, 2-amino-6-chloropyrazine (1.29 g, 10 mmol) was added in batches and the reaction mixture was heated at 80 °C for 2 hours. After completion of the reaction, it was cooled to room temperature, water was added and extracted with ethyl acetate. The organic layer was washed with brine, dried over anhydrous magnesium sulfate, filtered and concentrated. The residue was purified by column chromatography to afford 2-amino-6-methoxypyrazine (888 mg, 71% yield) as a light yellow solid.1H NMR (200 MHz, CDCl3) δ 7.60 (s, 1H), 7.55 (s, 1H), 4.44 (br, 2H), 3.90 (s, 3H). 2-Amino-6-methoxypyrazine (186 mg, 1.45 mmol) was dissolved in methanol, N-bromosuccinimide (568 mg, 3.19 mmol) was added, and stirred at room temperature for 30 min. The reaction mixture was concentrated under vacuum, ethyl acetate was added and washed with water. The organic layer was dried with anhydrous magnesium sulfate, filtered and concentrated. The residue was purified by column chromatography to afford the target product 1e (242 mg, 59% yield).1H NMR (200 MHz, CDCl3) δ 4.91 (br, 2H), 3.96 (s, 3H).
