反应详情

温度

85 °C

A solution of tert-butyl 5-methylpyrazin-2-ylcarbamate (2.79 g, 13.33 mmol), NBS (2.61 g, 14.67 mmol) and AlBN (0.219 g, 1.33 mmol) in CCl4 (45 mL) was purged with Argon, then the solution was heated with 85° C. oil bath for 4 h. The reaction mixture was cooled to room temperature, concentrated and the residue was redissolved in EtOAc (˜50 mL), washed with dilute aqueous NaOH twice (10 mL 1 N NaOH diluted in 20 mL H2O), brine (30 mL), dried (Na2SO4) and concentrated. The residue was further purified by flash chromatography on silica gel eluted with gradient EtOAc/CH2Cl2 (0-30%) and tert-butyl 5-(bromomethyl)pyrazin-2-ylcarbamate was obtained in off-white solid. LCMS (m/z): 288.1/290.1 (MH+), 0.82 min; 1H NMR (400 MHz, CDCl3) δ ppm 9.26 (s, 1H), 8.32 (d, J=1.2 Hz, 1H), 7.62 (br. s., 1H), 4.56 (s, 2H), 1.56 (s, 9H).

1. temperatureThe reaction mixture was cooled to room temperature
2. concentrationconcentrated
3. dissolutionthe residue was redissolved in EtOAc (˜50 mL)
4. washwashed with dilute aqueous NaOH twice (10 mL 1 N NaOH diluted in 20 mL H2O), brine (30 mL)
5. dry with materialdried (Na2SO4)
6. concentrationconcentrated
7. customThe residue was further purified by flash chromatography on silica gel
8. washeluted with gradient EtOAc/CH2Cl2 (0-30%)