Réaction #6644

Équation de réaction

2,2,4,4-tetramethylchroman

Compound 84

2,2,4,4-tetramethylchroman

aluminum chloride

acetyl chloride

→

title compound

2,2,4,4-Tetramethyl-6-acetyl-chroman

Solvants

nitromethane

Conditions de réaction

Traitement

1. 1
   workup.ADDITIONwas added, under nitrogen
2. 2
   AutreThe cooling bath was then removed
3. 3
   TempératureThe mixture was then cooled again in an ice bath
4. 4
   workup.ADDITIONtreated with 25 ml of conc. HCl
5. 5
   FiltrationThe mixture was then filtered
6. 6
   Lavagethe residue washed with methylene chloride
7. 7
   ConcentrationThe filtrate was concentrated in vacuo
8. 8
   Autrethe resultant residue was purified by flash chromatography (silica; 10% ethyl acetate in hexanes)

Mode opératoire

To an ice bath cooled solution of 2 g (10.53 mmol) of 2,2,4,4-tetramethylchroman (Compound 84) in 25 ml of nitromethane was added, under nitrogen, 941 mg (11.99 mmol) of acetyl chloride followed by 1.59 g (11.92) mmol) of aluminum chloride. The cooling bath was then removed and the mixture stirred at room temperature for 16 h. The mixture was then cooled again in an ice bath and treated with 25 ml of conc. HCl. The mixture was then filtered and the residue washed with methylene chloride. The filtrate was concentrated in vacuo and the resultant residue was purified by flash chromatography (silica; 10% ethyl acetate in hexanes) to give the title compound as a yellow oil. PMR (CDCl3): δ 1.38 (6H, s), 1.39 (6H, s), 1.87 (2H, s), 2.56 (3H, s), 6.83 (1H, d, J~8.7 Hz), 7.71 (1H, dd, J~8.7 Hz, 2.1 Hz), 7.98 (1H, d, J~2.1 Hz). MS exact mass, m/e 232.1468 (calcd. for C13H20O2, 232.1464).

Source