Reaktion #6640

Reaktionsgleichung

aluminum chloride

4,4-dimethylchroman

Compound 76

4,4-dimethylchroman

acetyl chloride

hydrogen chloride

→

title compound

4,4-Dimethyl-6-acetylchroman

Lösungsmittel

ether

nitromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturcooled in an ice bath
2. 2
   Sonstigethe organic layer separated
3. 3
   WaschenThe organic layer was washed with water, saturated NaHCO3 and saturated NaCl solutions
4. 4
   Trocknendried (MgSO4)
5. 5
   SonstigeSolvent was removed in vacuo
6. 6
   Sonstigethe residue purified by flash chromatography (silica; 10% ethyl acetate in hexanes)
7. 7
   workup.DISTILLATIONThis was followed by kugelrohr distillation (95-100 degrees C; 0.15 mm)

Vorschrift

To a stirred solution 7.94 g (48.9425 mmol) of 4,4-dimethylchroman (Compound 76) in 70 ml of nitromethane was added under argon 4.0 g (50.96 mmol) of acetyl chloride followed by 6.8 g (51 mmol) of aluminum chloride. This was stirred at room temperature for 5.5 hours and then cooled in an ice bath and treated slowly with 70 ml of 6N hydrogen chloride. The resultant mixture was stirred at room temperature for 10 minutes and then treated with 100 ml ether and the organic layer separated. The organic layer was washed with water, saturated NaHCO3 and saturated NaCl solutions and dried (MgSO4). Solvent was removed in vacuo and the residue purified by flash chromatography (silica; 10% ethyl acetate in hexanes). This was followed by kugelrohr distillation (95-100 degrees C; 0.15 mm) to give the title compound as a colorless oil. PMR (CDCl3): δ 1.40 (6H), 1.95-2.00 (2H, m), 2.58 (3H), 4.25-4.30 (2H, m), 6.83 (1H, d, J~18.0 Hz), 7.62 (1H, dd, J~8.0 Hz, 1.5 Hz), 8.00 (1H, d, J~1.5 Hz).

Quelle