反应详情

温度

115 °C

5-Methoxy-2-methyl-pyridine 1-oxide (9.25 g, 66.5 mmol) was suspended in acetic anhydride (31 ml) under an argon atmosphere. The mixture was heated to ca.115° C. and this temperature was maintained for a further 5 h and the mixture turned black. Ethanol (2.5 ml) was added and the mixture was concentrated under reduced pressure. The residue was taken up in ethyl acetate and washed with 10% K2CO3 and water. The aqueous phases were back extracted with ethyl acetate and the combined organic phases were dried (MgSO4) filtered and concentrate under reduced pressure. The crude oil was purified using Kugelrohr distillation (90-100° C./0.1 mbar) yielding a colorless oil: 10.7 g (80%); 1H NMR (CDCl3) δ 2.13 (s, 3H), 3.86 (s, 3H), 5.16 (s, 2H), 7.18-7.31 (m, 2H), 8.30 (d, 1H) MS: m/e=181.2 (M), 138.0 (M−COCH3)

1. temperatureThe mixture was heated to ca
2. concentrationthe mixture was concentrated under reduced pressure
3. washwashed with 10% K2CO3 and water
4. extractionThe aqueous phases were back extracted with ethyl acetate
5. dry with materialthe combined organic phases were dried (MgSO4)
6. filtrationfiltered
7. concentrationconcentrate under reduced pressure
8. customThe crude oil was purified
9. distillationKugelrohr distillation (90-100° C./0.1 mbar)
10. customyielding a colorless oil