Reaktion #356629

Reaktionsgleichung

2,6-dimethylindan-1-one

AlCl3

bromine

HCl

→

title product

4-Bromo-2,6-dimethylindan-1-one

Lösungsmittel

dichloromethane

dichloromethane

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGThis mixture was stirred for 1 h at ambient temperature
2. 2
   workup.STIRRINGwhile vigorously stirring for 2 h
3. 3
   workup.STIRRINGThe resulting mixture was stirred for 12 h
4. 4
   Sonstigethe organic layer was separated
5. 5
   Extraktionthe aqueous layer was extracted with 3×350 ml of dichloromethane
6. 6
   TrocknenThe combined organic fractions were dried over K2CO3
7. 7
   Sonstigeevaporated to dryness
8. 8
   workup.DISTILLATIONFrom the residue, 71.0 g of the starting indanone was distilled off in vacuum (bp 89-91 mm Hg)
9. 9
   workup.WAITthe solid material left in the rectification flask
10. 10
    Sonstigewas recrystallized from 600 ml of hot hexanes
11. 11
    SonstigeCrystals that precipitated at room temperature
12. 12
    Sonstigewere collected

Vorschrift

To a suspension of 334 g (2.50 mol) of anhydrous AlCl3 (powder) in 400 ml of dry dichloromethane, a solution of 160 g (1.00 mol) of 2,6-dimethylindan-1-one in 200 ml of dichloromethane was added dropwise while vigorously stirring for 30 min at 0° C. This mixture was stirred for 1 h at ambient temperature, and then a solution of 51.6 ml (161 g, 1.01 mol) of bromine in 800 ml of dichloromethane was added while vigorously stirring for 2 h. The resulting mixture was stirred for 12 h and then poured on 700 cm3 of ice. The mixture was acidified by saturated HCl to pH 1, the organic layer was separated, and the aqueous layer was extracted with 3×350 ml of dichloromethane. The combined organic fractions were dried over K2CO3 and then evaporated to dryness. From the residue, 71.0 g of the starting indanone was distilled off in vacuum (bp 89-91 mm Hg), and the solid material left in the rectification flask was recrystallized from 600 ml of hot hexanes. Crystals that precipitated at room temperature were collected. The pure title product was then isolated by flash chromatography on Silica Gel 60 (40-63 um, d 50 mm, l 1200 mm, eluent: hexanes-dichloromethane, 10:1, vol.). Yield 44.0 g (18%).

Quelle