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

HRID 924397Notes

Reaction equation

HRID 924397 reaction equation
[N+:1]1([O-])[CH:6]=[CH:5][CH:4]=[C:3]2[CH2:7][CH2:8][CH2:9][C:2]=12.P(Cl)(Cl)([Cl:13])=O>>[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 94%

Conditions

Temperature
120 °C

Procedure

6,7-Dihydro-5H-cyclopenta[b]pyridine 1-oxide (2.5 g, 18 mmol) was mixed with phosphoryl chloride (20 mL, 200 mmol). The reaction mixture was stirred at 120° C. for 3 h. The excess POCl3 was removed under reduced pressure. The residue was diluted in 80 mL of EtOAc and neutralized with Na2CO3 solution. After filtration, the aqueous layer was extracted with EtOAc twice. The combined organic extracts 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=154.2. Found: 154.3.

Workup

  1. customThe excess POCl3 was removed under reduced pressure
  2. additionThe residue was diluted in 80 mL of EtOAc and neutralized with Na2CO3 solution
  3. filtrationAfter filtration
  4. extractionthe aqueous layer was extracted with EtOAc twice
  5. customThe combined organic extracts were dried
  6. filtrationfiltered
  7. concentrationconcentrated under reduced pressure

Sources & evidence

ORD record
ord-5dd0709017394eb7a3f7935c286067bf
Source dataset
uspto-grants-2016_03
Patent number
US09278950B2

Reaction notes

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