반응 #1172208

반응 방정식

aluminum chloride

2,2,4,4,7-pentamethyl-chroman

Compound 52

2,2,4,4,7-pentamethyl-chroman

acetyl chloride

→

title compound

2,2,4,4,7-Pentamethyl-6-acetyl-chroman

용매

nitromethane

ether

water

반응 조건

후처리

1. 1
   온도cooled in an ice-bath
2. 2
   workup.ADDITIONtreated with 25 ml of conc. HC1
3. 3
   온도The mixture was warmed to room temperature
4. 4
   기타The organic layer was separated
5. 5
   추출the aqueous layer extracted with ether
6. 6
   세척washed successively with water, saturated NaHCO3 solution, water again
7. 7
   건조saturated NaCl solution, and then dried (MgSO4)
8. 8
   기타The solvent was removed in vacuo
9. 9
   기타the residue was purified by flash chromatography (silica; 5% ethyl acetate in hexanes)

실험 절차

To an ice-bath cooled solution of 1.96 g (9.6 mmol) of 2,2,4,4,7-pentamethyl-chroman (Compound 52) in 30 ml of nitromethane was added under argon 1.059 g (13.5 mmol) of acetyl chloride followed by 1.9 g (14.3 mmol) of aluminum chloride. The reaction mixture was stirred at room temperature for 14 h and then cooled in an ice-bath and treated with 25 ml of conc. HC1. The mixture was warmed to room temperature and diluted with ether and water. The organic layer was separated and the aqueous layer extracted with ether. The organic extracts were combined and washed successively with water, saturated NaHCO3 solution, water again, and saturated NaCl solution, and then dried (MgSO4). The solvent was removed in vacuo and the residue was purified by flash chromatography (silica; 5% ethyl acetate in hexanes) to give the title compound as a pale yellow oil. PMR (CDCl3): 1.36 (6H, s), 1.37 (6H, s), 1.86 (2H, s), 2.49 (3H, s), 2.56 (3H, s), 6.65 (1H, s), 7.74 (1H, s).

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