Sulfuric Acid → 2H-1-Benzopyran-6-ol, 3,4-dihydro-2-methoxy-2,5,7,8-tetramethyl-

HRID 263924Notes

Reaction equation

HRID 263924 reaction equation
S(=O)(=O)(O)O.[CH:6](OC)(OC)OC.[CH3:13][C:14]1[C:15]([OH:23])=[C:16]([CH3:22])[C:17]([CH3:21])=[C:18]([CH:20]=1)[OH:19].[CH:24]([C:26]([CH3:28])=[O:27])=[CH2:25]>CO.C(OCC)C>[OH:23][C:15]1[C:14]([CH3:13])=[C:20]2[C:18](=[C:17]([CH3:21])[C:16]=1[CH3:22])[O:19][C:26]([O:27][CH3:6])([CH3:28])[CH2:24][CH2:25]2

Participants

7

Reactant 4

HCID 1118Sulfuric AcidHCID 6570Methyl vinyl ketoneHCID 9005Trimethyl orthoformateHCID 12785Trimethylhydroquinone

Product 1

HCID 1037632H-1-Benzopyran-6-ol, 3,4-dihydro-2-methoxy-2,5,7,8-tetramethyl-Yield 92.6%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 3283Diethyl EtherSolvent

Procedure

Concentrated sulfuric acid (0.8 mL) was added dropwise to a solution of trimethyl orthoformate (Aldrich, 48.5 g, 457.0 mmol) and trimethyl hydroquinone (Aldrich, 50.0 g, 328.5 mol) in methanol (200 mL), cooled by a water/ice bath. Methyl vinyl ketone (Aldrich, 46.05 g, 657.0 mmol) was added slowly (1.5 h) to the reaction mixture while the reaction mixture was cooled by an ice/water bath. A pasty slurry formed. The reaction mixture was allowed to come to ambient temperature and was stirred at ambient temperature for 48 h. The reaction mixture was diluted with diethyl ether (600 mL) and the resulting solution was extracted with water (2×200 mL) and saturated aqueous sodium bicarbonate (2×100 mL). The organic solution was dried (sodium sulfate) and concentrated in vacuo to give a tan solid. The solid was recrystallized from methanol to give 71.8 g (92.6%) of the desired product as a tan solid.

Workup

  1. temperaturecooled by a water/ice bath
  2. temperaturewas cooled by an ice/water bath
  3. customA pasty slurry formed
  4. customto come to ambient temperature
  5. extractionthe resulting solution was extracted with water (2×200 mL) and saturated aqueous sodium bicarbonate (2×100 mL)
  6. dry with materialThe organic solution was dried (sodium sulfate)
  7. concentrationconcentrated in vacuo
  8. customto give a tan solid
  9. customThe solid was recrystallized from methanol

Sources & evidence

ORD record
ord-e869cbf248364ce393243da6e7bfa8b3
Source dataset
uspto-grants-1997_07
Patent number
US05646149

Reaction notes

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