2-Amino-3,5-dibromopyrazine → 2-Amino-5-bromo-3-methoxypyrazine

Participants

Reaction Steps

A 30% w/w solution of NaOMe in MeOH (8.4 mL, 44.8 mmol) was added to a stirring suspension of 3,5-dibromo-2-aminopyrazine (10 g, 39.5 mmol) in dry MeOH (40 mL). The reaction mixture was heated to reflux and maintained for 3 h. The reaction was allowed to cool to rt and concentrate to 1/3 volume. The reaction was then partitioned between DCM and saturated aqueous NaHCO3 solution. The layers were separated and the organic phase was washed with saturated aqueous NaHCO3 solution (3×). The combined aqueous portions were back extracted with DCM (3×). The combined organic portions were washed with brine, dried (Na2SO4), and concentrated to provide 8.1 g of 5-bromo-3-methoxypyrazin-2-amine: 1H NMR (300 MHz, CDCl3): 7.64 (s, 1H), 4.79 (br s, 2H), 4.01 (s, 3H).

Provenance & Evidence