Réaction #6640

Équation de réaction

aluminum chloride

4,4-dimethylchroman

Compound 76

4,4-dimethylchroman

acetyl chloride

hydrogen chloride

→

title compound

4,4-Dimethyl-6-acetylchroman

Solvants

ether

nitromethane

Conditions de réaction

Traitement

1. 1
   Températurecooled in an ice bath
2. 2
   Autrethe organic layer separated
3. 3
   LavageThe organic layer was washed with water, saturated NaHCO3 and saturated NaCl solutions
4. 4
   Séchagedried (MgSO4)
5. 5
   AutreSolvent was removed in vacuo
6. 6
   Autrethe 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)

Mode opératoire

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).

Source