Methanesulfonic Acid → 4,4,5,7-Tetramethylchroman-2-one

HRID 605392Notes

Reaction equation

HRID 605392 reaction equation
[CH3:1][C:2]1[CH:3]=[C:4]([OH:9])[CH:5]=[C:6]([CH3:8])[CH:7]=1.[CH3:10][C:11]([CH3:17])=[CH:12][C:13](OC)=[O:14].CS(O)(=O)=O>O>[CH3:10][C:11]1([CH3:17])[C:5]2[C:4](=[CH:3][C:2]([CH3:1])=[CH:7][C:6]=2[CH3:8])[O:9][C:13](=[O:14])[CH2:12]1

Participants

5

Reactant 3

HCID 6395Methanesulfonic AcidHCID 79483,5-DimethylphenolHCID 13546Methyl 3-methyl-2-butenoate

Product 1

HCID 6051634,4,5,7-Tetramethylchroman-2-oneYield 92.4%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

3,5-Dimethylphenol (5.00 g, 0.0409 mol) and methyl 3,3-dimethylacrylate (5.14 g, 0.045 mol) were added to methanesulfonic acid (5 mL) at room temperature followed by heating at 70° for 17 hours. The reaction was cooled, diluted with water (750 mL), extracted with ethyl acetate (2×200 mL) and the combined organic extracts were washed with saturated aqueous sodium hydrogencarbonate (2×100 mL) and brine (50 mL). The organic phase was dried over magnesium sulfate, filtered, and concentrated by rotary evaporation. Purification by silica gel flash chromatography eluting with methylene chloride afforded the title compound as a beige solid (7.73 g, 0.0378 mol, 92%). 1H NMR (300 MHz, CHLOROFORM-D) δ ppm 1.43 (s, 6 H) 2.27 (s, 3 H) 2.46 (s, 3 H) 2.59 (s, 2 H) 6.74 (s, 2 H). MS (DCI) m/z 205 (M+H)+, 222 (M+NH4)+.

Workup

  1. temperatureby heating at 70° for 17 hours
  2. temperatureThe reaction was cooled
  3. extractionextracted with ethyl acetate (2×200 mL)
  4. washthe combined organic extracts were washed with saturated aqueous sodium hydrogencarbonate (2×100 mL) and brine (50 mL)
  5. dry with materialThe organic phase was dried over magnesium sulfate
  6. filtrationfiltered
  7. concentrationconcentrated by rotary evaporation
  8. customPurification by silica gel flash chromatography
  9. washeluting with methylene chloride

Sources & evidence

ORD record
ord-130812644c67493f977587abbbc20e3f
Source dataset
uspto-grants-2011_03
Patent number
US07910595B2

Reaction notes

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