Phosphorus oxychloride → 7-Chloro-6-iodothieno[3,2-b]pyridine
Reaction equation
[I:1][C:2]1[C:3](O)=[C:4]2[S:10][CH:9]=[CH:8][C:5]2=[N:6][CH:7]=1.P(Cl)(Cl)([Cl:14])=O>>[Cl:14][C:3]1[C:2]([I:1])=[CH:7][N:6]=[C:5]2[CH:8]=[CH:9][S:10][C:4]=12Participants
3
Conditions
- Temperature
- 120 °C
Procedure
A mixture of the crude 6-iodothieno[3,2-b]pyridin-7-ol (0.99 g, 3.6 mmol) in phosphoryl chloride (20 mL) was heated at 120° C. for 2 h. The reaction was cooled to room temperature, concentrated under reduced pressure. The residue was co-evaporated with toluene, then diluted with dichloromethane and neutralized carefully with sat. NaHCO3 solution. The black tar was filtered off and the filtrate was transferred to a separation funnel. The organic layer was concentrated and purified on silica gel (eluting with 0-35% EtOAc/hexanes) to give the desired product (44% in 2 steps). LCMS calculated for C7H4ClINS (M+H)+: m/z=295.9. Found: 295.8.