Phosphorus oxychloride → 4-Chloro-5-nitro-2-(trifluoromethyl)pyridine
Reaction equation
[N+:1]([C:4]1[C:5](O)=[CH:6][C:7]([C:10]([F:13])([F:12])[F:11])=[N:8][CH:9]=1)([O-:3])=[O:2].P(Cl)(Cl)(Cl)(Cl)[Cl:16].O=P(Cl)(Cl)Cl>>[Cl:16][C:5]1[C:4]([N+:1]([O-:3])=[O:2])=[CH:9][N:8]=[C:7]([C:10]([F:13])([F:12])[F:11])[CH:6]=1Participants
4
Conditions
- Temperature
- 80 °C
Procedure
The crude 5-nitro-2-trifluoromethyl-pyridin-4-ol (3.4 g, 16.3 mmmol) was treated with PCl5 (5.2 g, 24.97 mmol) and POCl3 (7 mL, 24.49 mmol). The resulting mixture is heated at 80° C. for 18 h, cooled and poured into ice-cold water, and extracted with CH2Cl2. The combined organic phase is washed successively with saturated aqueous NaHCO3, water, brine, dried over Na2SO4, and concentrated in vacuo to afford 4-Chloro-5-nitro-2-trifluoromethyl-pyridine as an yellow oil. 1H NMR (300 MHz, CDCl3): δ 9.17 (s, 1H), 7.9 (s, 1H).