Phosphorus oxychloride → 6-Acetyl-7-chloro-1H-pyrazolo[4,3-b]pyridine
Reaction equation
[C:1]([C:4]1[C:5](=O)[C:6]2[NH:12][N:11]=[CH:10][C:7]=2[NH:8][CH:9]=1)(=[O:3])[CH3:2].P(Cl)(Cl)([Cl:16])=O>>[C:1]([C:4]1[C:5]([Cl:16])=[C:6]2[NH:12][N:11]=[CH:10][C:7]2=[N:8][CH:9]=1)(=[O:3])[CH3:2]Participants
3
Conditions
- Temperature
- 80 °C
Procedure
A mixture of 6-acetyl-4,7-dihydro-7-oxo-1H-pyrazolo-[4,3-b]pyridine (D14, 1.6 g, 9 mmol) and phosphorus oxychloride (15 ml) was heated at 80° C. for 30 min. Excess reagent was removed in vacuo, water was added and the mixture was adjusted to pH 9 with 10% sodium carbonate solution. The resulting mixture was extracted with ethyl acetate (4×50 ml), and the extracts were washed with brine, dried (MgSO4) and evaporated in vacuo to leave the title compound as a yellow solid, which was used without further purification.