Boron tribromide → 2-cyclopentyl-7-hydroxy-3,4-dihydroisoquinolin-1(2H)-one

HRID 404979Notes

Reaction equation

HRID 404979 reaction equation
B(Br)(Br)Br.[CH:5]1([N:10]2[CH2:19][CH2:18][C:17]3[C:12](=[CH:13][C:14]([O:20]C)=[CH:15][CH:16]=3)[C:11]2=[O:22])[CH2:9][CH2:8][CH2:7][CH2:6]1>C1C=CC=CC=1>[CH:5]1([N:10]2[CH2:19][CH2:18][C:17]3[C:12](=[CH:13][C:14]([OH:20])=[CH:15][CH:16]=3)[C:11]2=[O:22])[CH2:6][CH2:7][CH2:8][CH2:9]1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 667996072-cyclopentyl-7-methoxy-3,4-dihydroisoquinolin-1(2H)-one

Product 1

HCID 667995002-cyclopentyl-7-hydroxy-3,4-dihydroisoquinolin-1(2H)-oneYield 66%

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent

Procedure

BBr3 (1.836 g, 7.35 mmol) was added dropwise to a solution of 2-cyclopentyl-7-methoxy-3,4-dihydroisoquinolin-1(2H)-one (0.600 g, 2.45 mmol) in benzene (50 mL) at 0° C. The mixture was gradually warmed to room temperature and then heated at 80° C. for 30 min. The reaction mixture was then cooled to room temperature and carefully quenched with H2O. The resulting mixture was then heated at reflux for 1 hour and then cooled. Extraction with ethyl acetate and removal of the solvent in vacuo, followed by chromatographic separation (silica gel, CHCl3: CH3OH, 9:1) afforded 2-cyclopentyl-7-hydroxy-3,4-dihydroisoquinolin-1(2H)-one as a colorless solid (0.373 g, 66%). 1H NMR (DMSO-D6): δ 9.42 (s, 1H), 7.25 (s, 1H), 7.02 (d, 1H, J=8.6 Hz), 6.80 (d, 1H, J=8.5 Hz), 4.97-4.93 (m, 1H), 3.32 (t, 2H, J=6.1 Hz), 2.73 (t, 2H, J=6.7 Hz), 1.73-1.64 (m, 4H), 1.53-1.45 (m, 4H). LC-MS (ESI) Calcd for C14H17NO2 [M+H]+: 232.13. Found: 232.00.

Workup

  1. temperatureheated at 80° C. for 30 min
  2. temperatureThe reaction mixture was then cooled to room temperature
  3. customcarefully quenched with H2O
  4. temperatureThe resulting mixture was then heated
  5. temperatureat reflux for 1 hour
  6. temperaturecooled
  7. extractionExtraction
  8. customwith ethyl acetate and removal of the solvent in vacuo
  9. customfollowed by chromatographic separation (silica gel, CHCl3: CH3OH, 9:1)

Sources & evidence

ORD record
ord-cda13d0af5d4450ca4044e87d6ca78a9
Source dataset
uspto-grants-2014_06
Patent number
US08748632B2

Reaction notes

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