Phosphorus oxychloride → 4-chloro-5H,6H,7H-cyclopenta[b]pyridine
Reaction equation
[N+:1]1([O-])[CH:6]=[CH:5][CH:4]=[C:3]2[CH2:7][CH2:8][CH2:9][C:2]=12.O=P(Cl)(Cl)[Cl:13]>>[Cl:13][C:4]1[CH:5]=[CH:6][N:1]=[C:2]2[CH2:9][CH2:8][CH2:7][C:3]=12Participants
3
Conditions
- Temperature
- 120 °C
Procedure
6,7-Dihydro-5H-cyclopenta[b]pyridine 1-oxide (2.5 g, 18 mmol) was mixed with POCl3 (20 mL). The reaction mixture was stirred at 120° C. for 3 h. The excess POCl3 was removed under reduced pressure. The residue was diluted in EtOAc (80 mL) and neutralized with aq. Na2CO3. After filtration, the aqueous layer was extracted with EtOAc twice. The combined organic layers were dried, filtered and concentrated under reduced pressure to give the sub-title compound (2.6 g, 93%). LCMS calc. for C8H9ClN (M+H)+: m/z=154.0. Found: 154.3.