Methyl iodide → 2,3-Dihydro-4-hydroxy-7-methoxy-4-methyl-4H-1-benzopyran

HRID 236978Notes

Reaction equation

HRID 236978 reaction equation
[CH3:1]I.[Mg].[CH3:4][O:5][C:6]1[CH:16]=[CH:15][C:9]2[C:10](=[O:14])[CH2:11][CH2:12][O:13][C:8]=2[CH:7]=1.[Cl-].[NH4+]>CCOCC>[OH:14][C:10]1([CH3:1])[C:9]2[CH:15]=[CH:16][C:6]([O:5][CH3:4])=[CH:7][C:8]=2[O:13][CH2:12][CH2:11]1

Participants

6

Reactant 4

HCID 6328Methyl iodideHCID 25517Ammonium ChlorideHCID 43875107-methoxy-3,4-dihydro-2H-1-benzopyran-4-oneHCID 5462224Magnesium

Product 1

HCID 203045882,3-Dihydro-4-hydroxy-7-methoxy-4-methyl-4H-1-benzopyran

Reagents, catalysts & solvents 1

HCID 3283Diethyl EtherSolvent3×

Procedure

Methyl iodide (145 g; 64.2 ml) in dry ether (50 ml) was added dropwise with stirring to magnesium turnings (22 g) in dry ether (730 ml). After the initial reaction had ceased the reaction mixture was refluxed for 1/2 hour, cooled and 2,3-dihydro-7-methoxy-4-oxo-4H-1-benzopyran, (77.9 g) in dry ether (440 ml) was added dropwise with stirring. After addition the reaction mixture was refluxed for 1 hour, cooled and the complex was decomposed by the addition of ammonium chloride solution. The ethereal layer was separated, washed with water and dried. Evaporation of the solvent left 76 g of the title compound as an oil (89%). MS and NMR analysis were correct for the required compound.

Workup

  1. customAfter the initial reaction
  2. temperaturewas refluxed for 1/2 hour
  3. temperaturecooled
  4. additionAfter addition the reaction mixture
  5. temperaturewas refluxed for 1 hour
  6. temperaturecooled
  7. customThe ethereal layer was separated
  8. washwashed with water
  9. customdried
  10. customEvaporation of the solvent
  11. waitleft 76 g of the title compound as an oil (89%)

Sources & evidence

ORD record
ord-372e47da50834c18af7675729686de0d
Source dataset
uspto-grants-1979_06
Patent number
US04159273

Reaction notes

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