反应详情

Methyl 4-amino-5,6-dichloro-3-iodopicolinate (0.5 g, 1.4 mmol), vinyltributylstannane (530 μl, 0.57 mmol, 1.8 mmol), and bis(triphenylphosphine)palladium(II) chloride (0.10 g, 0.1 mmol) were combined in nitrogen-deaerated 1,2-dichloroethane (10 mL). The reaction mixture was heated at reflux for 8 hours. The cooled reaction mixture was diluted with ethyl acetate (30 mL) and stirred with 15% KHF2 solution (10 mL) for 30 minutes. The phases were separated and the aqueous phase was extracted with ethyl acetate. The combined organic phases were washed with saturated sodium chloride, dried over sodium sulfate, and concentrated under vacuum. The crude product was purified by flash chromatography (SiO2, ethyl acetate/hexane) to afford the title compound as a tan solid (0.26 g, 73%): mp 96-97° C.; 1H NMR (400 MHz, CDCl3) δ 6.85 (dd, J=18.1, 11.5 Hz, 1H), 5.72 (dd, J=11.5, 1.3 Hz, 1H), 5.53 (dd, J=18.1, 1.3 Hz, 1H), 5.19 (s, 2H), 3.91 (s, 3H); EIMS m/z 246 ([M−H)−].

1. temperatureThe reaction mixture was heated
2. temperatureat reflux for 8 hours
3. customThe cooled reaction mixture
4. customThe phases were separated
5. extractionthe aqueous phase was extracted with ethyl acetate
6. washThe combined organic phases were washed with saturated sodium chloride
7. dry with materialdried over sodium sulfate
8. concentrationconcentrated under vacuum
9. customThe crude product was purified by flash chromatography (SiO2, ethyl acetate/hexane)