Methyl iodide → 7-Methoxy-3,4-dihydroquinolin-2(1H)-one

HRID 1515331Notes

Reaction equation

HRID 1515331 reaction equation
[OH:1][C:2]1[CH:11]=[C:10]2[C:5]([CH2:6][CH2:7][C:8](=[O:12])[NH:9]2)=[CH:4][CH:3]=1.[C:13](=O)([O-])[O-].[K+].[K+].CI>CN(C)C=O>[CH3:13][O:1][C:2]1[CH:11]=[C:10]2[C:5]([CH2:6][CH2:7][C:8](=[O:12])[NH:9]2)=[CH:4][CH:3]=1

Participants

5

Reactant 3

HCID 6328Methyl iodideHCID 11430Potassium CarbonateHCID 27857587-Hydroxy-3,4-dihydrocarbostyril

Product 1

HCID 128994187-Methoxy-3,4-dihydroquinolin-2(1H)-oneYield 84.7%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

To a solution of 7-hydroxy-3,4-dihydro-quinolin-2(1H)-one (1.50 g) in N,N-dimethylformamide (10 ml), potassium carbonate (1.85 g) and methyl iodide (0.63 ml) were added and stirred overnight at room temperature. Insoluble materials were filtered off and the filtrate was concentrated. The resulting residue was diluted with ethyl acetate and then washed sequentially with water, saturated aqueous sodium thiosulfate:brine (1:1) and brine, followed by distilling off the solvent under reduced pressure. The resulting residue was diluted with n-hexane, and the crystal was collected by filtration to give 7-methoxy-3,4-dihydroquinolin-2(1H)-one (1.38 g) as a colorless crystal. To a solution of 7-methoxy-3,4-dihydroquinolin-2(1H)-one thus obtained (1.38 g) in tetrahydrofuran (30 ml), lithium aluminum hydride (592 mg) was added under ice cooling, heated under reflux for 4.5 hours, and then stirred overnight at room temperature. The reaction mixture was diluted with 28% aqueous ammonia under ice cooling and filtered to remove insoluble materials. The filtrate was evaporated under reduced pressure to remove the solvent. The resulting residue was purified by silica gel column chromatography (eluting solvent: n-hexane:ethyl acetate=20:1 to 9:1) to give the titled compound, i.e., 7-methoxy-1,2,3,4-tetrahydroquinoline (1.18 g) as a yellow oil.

Workup

  1. filtrationInsoluble materials were filtered off
  2. concentrationthe filtrate was concentrated
  3. additionThe resulting residue was diluted with ethyl acetate
  4. washwashed sequentially with water, saturated aqueous sodium thiosulfate:brine (1:1) and brine
  5. distillationby distilling off the solvent under reduced pressure
  6. additionThe resulting residue was diluted with n-hexane
  7. filtrationthe crystal was collected by filtration

Sources & evidence

ORD record
ord-66727ab25a9a431780b7d1d555dd3a3d
Source dataset
uspto-grants-2012_07
Patent number
US08222417B2

Reaction notes

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