反应详情

A solution of 2,6-dimethyl-3-nitropyridine (50 g, 329 mmol) and SeO2 (5.02 g, 27.9 mmol) in dioxane (500 mL) was heated at reflux for 16 hours. The solution was filtered, the solvent removed and the residue purified by column chromatography directly (20% EtOAc/hexanes). The material was recrystalized from ethyl acetate to give 41 g of 6-methyl-5-nitropicolinaldehyde (41 g, 75%), a pale yellow solid; 1HNMR (CDCl3, 400 MHz) δ 2.94 (s, 3H), 7.98 (d, J=8.34, 1H), 8.41 (d, J=8.34, 1H), 10.09 (s, 1H). Exact mass calculated for C7H6N2O3: 166.04. found: 167.12 MS m/z (MH+).

1. temperatureat reflux for 16 hours
2. filtrationThe solution was filtered
3. customthe solvent removed
4. customthe residue purified by column chromatography directly (20% EtOAc/hexanes)
5. customThe material was recrystalized from ethyl acetate