反应详情

2-Hydroxy-5-nitro-pyridine (5 g) was treated with sodium chlorodifluoro-acetate (11.5 g) in refluxing acetonitrile (186 ml) for 2 days. The solvent was evaporated, the residue poured into ethyl acetate, washed with brine, dried over sodium sulfate and then concentrated in vacuo. Chromatography on silica gel (eluent: hexane/ethyl acetate 1:1) afforded 2-difluoromethoxy-5-nitro-pyridine (1 g) and 1-difluoromethyl-5-nitro-1H-pyridin-2-one (90 mg). 2-Difluoromethoxy-5-nitro-pyridine: MS (ES+) 191 (MH+); 1H NMR (400 MHz, CDCl3) 7.05 (d, 1H), 7.51 (t, 1H), 8.53 (dd, 1H), 9.09 (d, 1H). 1-Difluoromethyl-5-nitro-1H-pyridin-2-one: MS (ES+) 191 (MH+); 1H NMR (400 MHz, CDCl3) 6.65 (d, 1H), 7.63 (t, 1H), 8.14 (dd, 1H), 8.73 (d, 1H).

1. customThe solvent was evaporated
2. additionthe residue poured into ethyl acetate
3. washwashed with brine
4. dry with materialdried over sodium sulfate
5. concentrationconcentrated in vacuo