反应详情

温度

0 °C

Sodium hydride (60% dispersion in mineral oil, 1.228 g=0.74 g NaH) was suspended in DMF (45 ml) under an argon atmosphere. The stirred suspension was cooled to 0° C. and 2-hydroxy-3-nitropyridine (4 g) was added portion wise over a period of 45 min. The mixture containing a compact yellow precipitate was then stirred at r.t. for 30 min and was cooled again to 0C. A solution of 2-chloro-2-ethoxyacetic acid ethyl ester (4.99 g) in DMF (5 ml) was then added and stirring at r.t. was continued for 2 h 30. The mixture was diluted with EtOAc and washed with water. The aqueous phase was extracted with EtOAc. The combined organics were washed with water and brine, dried (MgSO4), filtered and concentrated. The crude product was purified by chromatography (silica gel, gradient cyclohexane=>cyclohexane/EtOAc 3:2) to give (RS)-ethoxy-(3-nitro-2-oxo-2H-pyridin-1-yl)-acetic acid ethyl ester (4.32 g) as yellow solid. MS 270.1 ([M]+)

1. additionThe mixture containing a compact yellow precipitate
2. stirringstirring at r.t.
3. waitwas continued for 2 h
4. washwashed with water
5. extractionThe aqueous phase was extracted with EtOAc
6. washThe combined organics were washed with water and brine
7. dry with materialdried (MgSO4)
8. filtrationfiltered
9. concentrationconcentrated
10. customThe crude product was purified by chromatography (silica gel, gradient cyclohexane=>cyclohexane/EtOAc 3:2)