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

HRID 327346

Reaktionsgleichung

Reaktionsgleichung von HRID 327346
[CH3:1][C:2]1[CH:3]=[C:4]([OH:9])[CH:5]=[C:6]([CH3:8])[CH:7]=1.[CH3:10][C:11]([CH3:18])=[CH:12][C:13](OCC)=[O:14].S(=O)(=O)(O)O.CCOCC>C1C=CC=CC=1>[CH3:10][C:11]1([CH3:18])[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

Komponenten

6

Edukt 4

HCID 1118Sulfuric AcidHCID 3283Diethyl EtherHCID 79483,5-DimethylphenolHCID 12516Ethyl 3,3-dimethylacrylate

Produkt 1

HCID 6051634,4,5,7-Tetramethylchroman-2-one

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 241BenzeneLösungsmittel

Versuchsvorschrift

3,5-Dimethylphenol (IIa) (3.2 g, 26.2 mmol), ethyl 3,3-dimethylacrylate (5 mL, 36 mmol, 1.4 eq.) and concentrated sulfuric acid (1.5 mL) were dissolved in anhydrous benzene (30 mL), and the reaction mixture was heated to reflux for 2 h. The reaction mixture was cooled to room temperature and washed successively with water (2×40 mL), 5% aqueous NaHCO3 solution (2×20 mL), brine (2×20 mL) and dried over anhydrous sodium sulfate. After filtering off the desiccant, the solvent was removed under vacuum to obtain a dark brown gummy material. To this gummy material was added anhydrous ether (5 mL) and boiled for 2 min on a steam bath. The title compound, IIIa, (3.34 g, 16.4 mmol, Y: 62.4%) was crystallized out from the mixture upon cooling in an ice bath; mp, 95.8-96.3° C.; 1H-NMR (300 MHz, acetone-d6) δ ppm: 1.41 (6H, s, 4,4-Me2), 2.24 (3H, s, 5-Me), 2.46 (3H, s, 7-Me), 2.61 (2H, s, 3-H2), 6.68 (1H, s, Ar-H), 6.76 (1H, s, Ar-H); MS (Isobutane-DCI) m/e: 205 (M+H)+ ; IR (KBr) ν max: 1770, 1250, 1190, 870 cm-1.

Aufarbeitung

  1. temperaturethe reaction mixture was heated
  2. temperatureto reflux for 2 h
  3. washwashed successively with water (2×40 mL), 5% aqueous NaHCO3 solution (2×20 mL), brine (2×20 mL)
  4. dry with materialdried over anhydrous sodium sulfate
  5. filtrationAfter filtering off the desiccant
  6. customthe solvent was removed under vacuum
  7. customto obtain a dark brown gummy material
  8. customThe title compound, IIIa, (3.34 g, 16.4 mmol, Y: 62.4%) was crystallized out from the mixture
  9. temperatureupon cooling in an ice bath
  10. custommp, 95.8-96.3° C.

Quellen und Nachweise

ORD-Eintrag
ord-b87a5b01c0294c0b872738525ee85f24
Quelldatensatz
uspto-grants-1993_12
Patentnummer
US05272171

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