Paeonol → 7-Methoxy-n-methylspiro[2h-1-benzopyran-2,4'-piperidine]-4(3h)-one

HRID 479446Notes

Reaction equation

HRID 479446 reaction equation
[CH3:1][C:2]([C:4]1[CH:9]=[CH:8][C:7]([O:10][CH3:11])=[CH:6][C:5]=1[OH:12])=[O:3].[CH3:13][N:14]1[CH2:19][CH2:18][C:17](=O)[CH2:16][CH2:15]1.N1CCCC1>CO>[CH3:11][O:10][C:7]1[CH:8]=[CH:9][C:4]2[C:2](=[O:3])[CH2:1][C:17]3([O:12][C:5]=2[CH:6]=1)[CH2:18][CH2:19][N:14]([CH3:13])[CH2:15][CH2:16]3

Participants

5

Reactant 3

HCID 11092PaeonolHCID 31268PyrrolidineHCID 740491-Methyl-4-piperidone2×

Product 1

HCID 187709247-Methoxy-n-methylspiro[2h-1-benzopyran-2,4'-piperidine]-4(3h)-oneYield 98.7%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

To a stirred solution of 2-hydroxy-4-methoxyacetophenone (4.08 g, 24.58 mmol) in anhydrous methyl alcohol (60 cm3) under an atmosphere of dry nitrogen was added 1-methyl-4-piperidinone (3 cm3, 24.58 mmol) followed by pyrrolidine (4 cm3, 47.92 mmol) and the solution was heated to reflux. After 7 h, a further portion of 1-methyl-4-piperidinone (0.6 cm3, 4.76 mmol) was added and the mixture was heated to reflux for a further 4.5 h. It was then allowed to cool to room temperature before the volatile fractions were removed under reduced pressure. The resulting oil was treated with dichloromethane (100 cm3), washed with water (5×100 cm3), dried over anhydrous sodium sulfate to afford a dark viscous oil (6.33 g, 24.25 mmol) which partially crystallised on standing over a long period of time.

Workup

  1. temperaturethe solution was heated to reflux
  2. temperaturethe mixture was heated
  3. temperatureto reflux for a further 4.5 h
  4. customwere removed under reduced pressure
  5. additionThe resulting oil was treated with dichloromethane (100 cm3)
  6. washwashed with water (5×100 cm3)
  7. dry with materialdried over anhydrous sodium sulfate

Sources & evidence

ORD record
ord-97ec17c593a0415f8aab814c53c3f5f6
Source dataset
uspto-grants-2003_11
Patent number
US06645973B1

Reaction notes

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