反应详情

温度

-5 °C

Following a literature procedure (Synthesis 1996, 877), n-BuLi (2.2 M in hexane, 9.1 mL, 20 mmol) was added dropwise to solution of tert-butyl 3-methylpyridin-2-ylcarbamate (1.98 g, 9.5 mmol) in dry THF (21 mL) at −5° C. The reaction was maintained at −5° C. for 1 h, then cooled to −78° C. in a dry ice-acetone bath. A solution of MeI (0.62 mL, 10 mmol) in dry THF (3 mL) was added over 20 min. The reaction was maintained at −78° C. for 1 h and then raised slowly to −55° C. The reaction was quenched with water (20 mL) and the resulting mixture was partitioned and the layers separated. The aqueous phase was extracted with EtOAc (2×20 mL) and the combined organic portions were washed with brine, dried (Na2CO3), and concentrated to furnish 1.8 g of tert-butyl 3-ethylpyridin-2-ylcarbamate: LCMS (m/z): 223.1 (MH+), tR=0.54 min

1. temperaturecooled to −78° C. in a dry ice-acetone bath
2. temperatureThe reaction was maintained at −78° C. for 1 h
3. temperatureraised slowly to −55° C
4. customThe reaction was quenched with water (20 mL)
5. customthe resulting mixture was partitioned
6. customthe layers separated
7. extractionThe aqueous phase was extracted with EtOAc (2×20 mL)
8. washthe combined organic portions were washed with brine
9. dry with materialdried (Na2CO3)
10. concentrationconcentrated