7-Bromopyrido[2,3-b]pyrazine

38875-53-5

131543-46-9

52333-42-3

7-Bromopyrido[2,3-b]pyrazine was synthesized by reacting 2,3-diamino-5-bromopyridine (2 g, 10.6 mmol) and glyoxal (5 mL, 40% aqueous solution) in ethanol (25 mL). The reaction mixture was allowed to stand for 48 hours and then concentrated in vacuum. The resulting residue was ground with ether and dried over air to afford the target product 7-bromopyrido[2,3-b]pyrazine (2.04 g, 92% yield) as a pinkish brown solid. The structure of the product was confirmed by 1H NMR (d6-DMSO): δ 9.28 (d, 1H), 9.20 (d, 1H), 9.12 (d, 1H), 8.95 (d, 1H). LC-MS (ES+) analysis showed m/z 212 ([M+H]+) and retention time (RT) was 1.98 min.