反应详情

温度

90 °C

2,6-dibromopyridine-N-oxide (6.28 g) was dissolved in concentrated sulphuric acid (20 ml) with stirring. A mixture of concentrated sulphuric acid (20 ml) and concentrated nitric acid (10 ml) was then continuously added dropwise. The solution was then heated at 90° C. for 3 hours with stirring, poured onto ice and then basified with sodium hydroxide. The solution was then continuously extracted with ether, and recrystallised from ethanol to give pale yellow leaflets of 4-nitro-2,6-dibromopyridine-N-oxide (1.2 g, 16%), m.p. 222° C.-224° C.

1. additionwas then continuously added dropwise
2. stirringwith stirring
3. additionpoured onto ice
4. extractionThe solution was then continuously extracted with ether
5. customrecrystallised from ethanol