反应详情

温度

90 °C

To a solution of boronic ester (6.64 g, 31.6 mmol), 5-bromopyrazin-2-amine (5 g, 28.7 mmol), and PdCl2(dppf) (2.1 g, 2.87 mmol) was added DME (71.8 mL) and 2 M Na2CO3 solution (24 mL). The reaction mixture was heated at 90° C. for 15 h. The reaction mixture was worked up with EtOAc. The organic layer was washed with water and brine, dried over anhydrous sodium sulfate, filtered off, and concentrated in vacuo. The crude product was purified by flash chromatography (gradient EtOAc in heptanes) yielding 5-(3,6-dihydro-2H-pyran-4-yl)pyrazin-2-amine in 57% yield. LCMS (m/z): 178.1 (MH+), 0.34 min; 1H NMR (400 MHz, CDCl3) δ ppm 8.17-8.03 (m, 1H), 8.04-7.88 (m, 1H), 6.57-6.41 (m, 1H), 4.68-4.42 (m, 2H), 4.42-4.29 (m, 2H), 4.06-3.84 (m, 2H), 2.68-2.47 (m, 2H).

1. washThe organic layer was washed with water and brine
2. dry with materialdried over anhydrous sodium sulfate
3. filtrationfiltered off
4. concentrationconcentrated in vacuo
5. customThe crude product was purified by flash chromatography (gradient EtOAc in heptanes)