反应详情

Under nitrogen, a solution of 156 g (0.90 mol) of 3-bromopyridine N-oxide from step 1 was dissolved in 1000 mL of acetonitrile and treated with 256 mL (1.84 mol) of triethylamine and 275 g (2.8 mol) of trimethylsilyl cyanide. The reaction was stirred at reflux overnight and concentrated in vacuo; the residue was dissolved in 2.5M aqueous sodium hydroxide and extracted with methylene chloride. The organic phase was dried (MgSO4) and concentrated in vacuo; this residue was decolorized with carbon and recrystallized from methanol to give 42.2 g (26%) of 2-cyano-3-bromopyridine as a cream colored solid: mp 97°-98° C.; NMR (CDCl3)δ7.42 (dd, J=8 and 5 Hz, 1H), 8.05 (dd, J=8 and 2 Hz, 1H), 8.67 (dd, J=5 and 2 Hz, 1H).

1. temperatureat reflux overnight
2. concentrationconcentrated in vacuo
3. dissolutionthe residue was dissolved in 2.5M aqueous sodium hydroxide
4. extractionextracted with methylene chloride
5. dry with materialThe organic phase was dried (MgSO4)
6. concentrationconcentrated in vacuo
7. customrecrystallized from methanol