Phosphorus oxychloride → 2-Chloro-5-nitro-3-(trifluoromethyl)pyridine
Reaction equation
[N+:1]([C:4]1[CH:5]=[C:6]([C:11]([F:14])([F:13])[F:12])[C:7](O)=[N:8][CH:9]=1)([O-:3])=[O:2].P(Cl)(Cl)(Cl)(Cl)[Cl:16].P(Cl)(Cl)(Cl)=O>>[Cl:16][C:7]1[C:6]([C:11]([F:14])([F:13])[F:12])=[CH:5][C:4]([N+:1]([O-:3])=[O:2])=[CH:9][N:8]=1Participants
4
Conditions
- Temperature
- 90 °C
Procedure
A mixture of 5-nitro-3-(trifluoromethyl)pyridin-2-ol (2.65 g), phosphorus pentachloride (3.17 g) and phosphorus oxychloride (1.5 mL) was stirred at 90° C. for 3 hr. After cooling to room temperature, the reaction mixture was poured into ice, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (eluent: hexane-ethyl acetate=19:1→3:1) to give the title compound as a yellow oil (yield 2.21 g, 77%).
Workup
- temperatureAfter cooling to room temperature
- additionthe reaction mixture was poured into ice
- extractionthe mixture was extracted with ethyl acetate
- washThe extract was washed with saturated brine
- dry with materialdried over anhydrous magnesium sulfate
- concentrationconcentrated under reduced pressure
- customThe residue was purified by silica gel column chromatography (eluent: hexane-ethyl acetate=19:1→3:1)
Sources & evidence
- ORD record
- ord-630569306f734470b72031e4e424e3de
- Source dataset
- uspto-grants-2013_05
- Patent number
- US08436187B2
Reaction notes
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