Phosphorus oxychloride → 4-chloro-5H,6H,7H-cyclopenta[b]pyridine

HRID 1499438Notes

Reaction equation

HRID 1499438 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]=12

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 131533156,7-Dihydro-5H-cyclopenta[b]pyridine 1-oxide

Product 1

HCID 122033274-chloro-5H,6H,7H-cyclopenta[b]pyridineYield 93%

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.

Workup

  1. customThe excess POCl3 was removed under reduced pressure
  2. additionThe residue was diluted in EtOAc (80 mL)
  3. filtrationAfter filtration
  4. extractionthe aqueous layer was extracted with EtOAc twice
  5. customThe combined organic layers were dried
  6. filtrationfiltered
  7. concentrationconcentrated under reduced pressure

Sources & evidence

ORD record
ord-46da843332ba4d9cb87df6ad4e5e9a03
Source dataset
uspto-grants-2015_12
Patent number
US09200004B2

Reaction notes

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