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

HRID 1508995Notes

Reaction equation

HRID 1508995 reaction equation
[Cl:1][C:2]1[CH:7]=[C:6]([O:8][CH:9]([CH3:11])[CH3:10])[N+:5]([O-])=[C:4]2[CH2:13][CH2:14][CH2:15][C:3]=12.P(Cl)(Cl)Cl>C(Cl)Cl>[Cl:1][C:2]1[CH:7]=[C:6]([O:8][CH:9]([CH3:11])[CH3:10])[N:5]=[C:4]2[CH2:13][CH2:14][CH2:15][C:3]=12

Participants

4

Reactant 2

HCID 24387Phosphorus trichlorideHCID 901107724-chloro-2-isopropoxy-6,7-dihydro-5H-cyclopenta[b]pyridine oxide

Product 1

HCID 901123734-chloro-2-isopropoxy-6,7-dihydro-5H-cyclopenta[b]pyridineYield 77%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a solution of 4-chloro-2-isopropoxy-6,7-dihydro-5H-cyclopenta[b]pyridine 1-oxide (0.079 g, 0.35 mmol) in methylene chloride (5 mL) was added phosphorous trichloride (0.096 g, 0.70 mmol). The mixture stirred at rt for 30 min. After this time, the mixture was quenched with a saturated solution of NaHCO3 and extracted with methylene chloride. The organic layer were 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 (0.057 g, 77%) as a clear oil. MW=211.69. 1H NMR (CDCl3, 300 MHz) δ 6.47 (s, 1H), 5.27-5.18 (m, 1H), 3.01-2.84 (m, 4H), 2.11 (quin, J=7.5 Hz, 2H), 1.31 (d, J=6.0 Hz, 6H); APCI MS m/z 212 [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 were 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-79be5676ea8d42ba819c1d2d3af0385b
Source dataset
uspto-grants-2015_12
Patent number
US09221843B2

Reaction notes

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