反应详情

A solution of 9 g of ethyl 2-methylnicotinate in 250 mL methylene chloride is stirred at room temperature and 32 g of 80% metachloroperoxybenzoic acid is added in one portion. The resulting solution is stirred for three days. The precipitated solid is filtered off, and the filtrate is washed with cold, dilute aqueous sodium hydroxide, dried, and concentrated in vacuo to afford the crude N-oxide. This material is digested in 75 mL of 1,2-dichloroethane; 15 mL of phosphorous oxychloride is added, and the solution is heated at reflux overnight. The solution is concentrated in vacuo, and the residue is taken up in methylene chloride and neutralized with aqueous sodium acetate. The organic phase is dried, concentrated in vacuo, and the residue is chromatographed on silica gel using hexane-ethyl acetate mixtures to afford 1.2 g of the title product as an oil having

1. filtrationThe precipitated solid is filtered off
2. washthe filtrate is washed with cold, dilute aqueous sodium hydroxide
3. customdried
4. concentrationconcentrated in vacuo
5. customto afford the crude N-oxide
6. temperaturethe solution is heated
7. temperatureat reflux overnight
8. concentrationThe solution is concentrated in vacuo
9. customThe organic phase is dried
10. concentrationconcentrated in vacuo
11. customthe residue is chromatographed on silica gel