反应详情

5,6-Dimethyl-3-nitro-pyridin-2,4-diol (3.9 g, 21 mmol) was dissolved in acetonitrile (150 mL) and firstly tetraethylammonium chloride (7.1 g, 42 mmol) and then phosphorus oxychloride (19.9 mL, 210 mmol) were added and the whole heated at 70C for 16 h. The reaction mixture was poured into crushed ice and extracted with DCM (2×30 mL). The combined extracts were dried over MgSO4, filtered and concentrated in vacuo to afford a brown solid. This solid was taken up in 2 mL DCM and filtered through a short plug of silica gel eluting with 2:1 pentane:EtOAc. The filtrate was then evaporated to afford the title compound as a light brown solid (3.5 g, 75%).

1. additionThe reaction mixture was poured
2. custominto crushed ice
3. extractionextracted with DCM (2×30 mL)
4. dry with materialThe combined extracts were dried over MgSO4
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. customto afford a brown solid
8. filtrationfiltered through a short plug of silica gel eluting with 2:1 pentane
9. customThe filtrate was then evaporated