Phosphorus trichloride → 4-chloro-2-(cyclopentyloxy)-6,7-dihydro-5H-cyclopenta[b]pyridine

HRID 1508987Notes

Reaction equation

HRID 1508987 reaction equation
[Cl:1][C:2]1[CH:7]=[C:6]([O:8][CH:9]2[CH2:13][CH2:12][CH2:11][CH2:10]2)[N+:5]([O-])=[C:4]2[CH2:15][CH2:16][CH2:17][C:3]=12.P(Cl)(Cl)Cl>C(Cl)Cl>[Cl:1][C:2]1[CH:7]=[C:6]([O:8][CH:9]2[CH2:13][CH2:12][CH2:11][CH2:10]2)[N:5]=[C:4]2[CH2:15][CH2:16][CH2:17][C:3]=12

Participants

4

Reactant 2

HCID 24387Phosphorus trichlorideHCID 901125474-chloro-2-(cyclopentyloxy)-6,7-dihydro-5H-cyclopenta[b]pyridine 1-oxide

Product 1

HCID 903386264-chloro-2-(cyclopentyloxy)-6,7-dihydro-5H-cyclopenta[b]pyridineYield 25%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a solution of crude 4-chloro-2-(cyclopentyloxy)-6,7-dihydro-5H-cyclopenta[b]pyridine 1-oxide (0.49 mmol) in methylene chloride (5 mL) was added phosphorous trichloride (0.100 g, 0.74 mmol). The mixture stirred at rt for 2 h. After this time, the mixture was quenched with a saturated solution of NaHCO3 and extracted with methylene chloride. The organic layer was dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated. The residue was purified by column chromatography (silica, hexanes/ethyl acetate) to afford the title compound (0.029 g, 25% over two steps) as a clear oil. MW=237.73. 1H NMR (CDCl3, 300 MHz) δ 6.45 (s, 1H), 5.34-5.26 (m, 1H), 3.01-2.84 (m, 4H), 2.11 (quip; J=7.5 Hz, 2H), 2.00-1.57 (m, 8H); APCI MS m/z 238 [M+H]+.

Workup

  1. customAfter this time, the mixture was quenched with a saturated solution of NaHCO3
  2. extractionextracted with methylene chloride
  3. dry with materialThe organic layer was dried over anhydrous sodium sulfate
  4. filtrationfiltered
  5. concentrationthe filtrate was concentrated
  6. customThe residue was purified by column chromatography (silica, hexanes/ethyl acetate)

Sources & evidence

ORD record
ord-9f6458f60f504c02aea840c48f69e713
Source dataset
uspto-grants-2015_12
Patent number
US09221843B2

Reaction notes

Loading…