反应详情

A mixture of 2,5-dibromopyrazine (22-1, 20.0 g, 84.1 mmol), 2-methoxyethanol (6.40 g, 84.1 mmol), and sodium tert-butoxide (11.3 g, 118 mmol) in 168 mL of THF was stirred at room temperature overnight. The solution was concentrated under reduced pressure and added with ethyl acetate. The mixture was filtered and the filtrate was concentrated under reduced pressure. The residue was purified by column chromatography on silica gel (EtOAc:hexanes=1:5 as eluant) to give 2-bromo-5-(2-methoxyethoxy)pyrazine (22-2, 17.2 g) as yellow oil in 88% yield: 1H NMR (500 MHz, CDCl3) δ 8.16 (d, J=1.0 Hz, 1 H), 8.07 (d, J=1.0 Hz, 1 H), 4.46 (t, J=5.0 Hz, 2 H), 3.74 (m, 2 H), 3.43 (s, 3 H).

1. concentrationThe solution was concentrated under reduced pressure
2. additionadded with ethyl acetate
3. filtrationThe mixture was filtered
4. concentrationthe filtrate was concentrated under reduced pressure
5. customThe residue was purified by column chromatography on silica gel (EtOAc:hexanes=1:5 as eluant)