反应详情

To a solution of 5-chloro-3-(methoxycarbonyl)-2-methylpyrazine 1-oxide (8.83 g, 43.6 mmol) in toluene (100 mL) at 0° C. was added phosphorus oxychloride (10 ml, 109 mmol) and DMF (1 ml, 12.91 mmol). The reaction mixture was stirred at room temperature for 1 h, and then was heated to 85° C. fort 8 h. The mixture was cooled to RT and concentrated. The residue was diluted with EtOAc and washed with saturated NaHCO3 solution. The combined organic extracts were dried (MgSO4), filtered and concentrated in vacuo. The crude mixture was purified with ISCO (0% to 10% EtOAc/Hexanes) to afford the desired methyl 5,6-dichloro-3-methylpyrazine-2-carboxylate (6.51 g, 68% yield). 1H NMR (300 MHz, CDCl3) δ ppm 4.00 (3H, s), 2.83 (3H, s)

1. temperaturewas heated to 85° C.
2. waitfort 8 h
3. temperatureThe mixture was cooled to RT
4. concentrationconcentrated
5. additionThe residue was diluted with EtOAc
6. washwashed with saturated NaHCO3 solution
7. dry with materialThe combined organic extracts were dried (MgSO4)
8. filtrationfiltered
9. concentrationconcentrated in vacuo
10. customThe crude mixture was purified with ISCO (0% to 10% EtOAc/Hexanes)