反应详情

To a solution of 2-amino-5-fluoropyridine (8.6 g, 77 mmol) in conc. sulfuric acid (40 ml) was added dropwise (30 min) fuming nitric acid (3.25 ml, 77 mmol) at a temperature of +3° C. The reaction mixture was stirred at room temperature for 1 h and at +55° C. for 1 h. The mixture was poured onto ice and neutralized with 10 M sodium hydroxide and was extracted with methylene chloride. The organic layer was separated, dried over sodium sulfate and evaporated under reduced pressure. The residue was purified twice by column chromatography on silica gel, using (i) methanol:methylene chloride (1:20) and (ii) diethyl ether:petroleum ether (1:1) as eluent to give the title compound (0.44 g, 3.6%).

1. extractionwas extracted with methylene chloride
2. customThe organic layer was separated
3. dry with materialdried over sodium sulfate
4. customevaporated under reduced pressure
5. customThe residue was purified twice by column chromatography on silica gel