Phosphorus oxychloride → 4-Chloro-5-iodonicotinonitrile
Reaction equation
O[C:2]1[C:7]([C:8]#[N:9])=[CH:6][N:5]=[CH:4][C:3]=1[I:10].O=P(Cl)(Cl)[Cl:13]>>[Cl:13][C:2]1[C:7]([C:8]#[N:9])=[CH:6][N:5]=[CH:4][C:3]=1[I:10]Participants
3
Conditions
- Temperature
- 100 °C
Procedure
A mixture of 4-hydroxy-5-iodonicotinonitrile (57.5 g, 234 mmol) and POCl3 (200 mL) was heated at 100° C. for 2 hours, cooled to room temperature and evaporated to remove excess POCl3. The residue was cooled in an ice-water bath, adjusted to pH 8-9 with aqueous 10 N NaOH and extracted with ethyl acetate. The combined organics were washed with water and brine, dried over magnesium sulfate and concentrated. The resulting solid residue was washed with a minimum amount of methanol and methylene chloride to give 46.5 g (75%) of 4-chloro-5-iodonicotinonitrile as a tan solid. Melting range: 120-122° C.