Reaktion #5692

Reaktionsgleichung

5-chloroindole

benzyl bromide

18-crown-6

potassium tert-butoxide

→

1-benzyl-5-chloroindole

Ausbeute 90.0%

Lösungsmittel

Water

ether

ether

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwas added
2. 2
   workup.DISSOLUTIONMost of the solid dissolved
3. 3
   workup.WAITThe stirring was continued for 27 hours
4. 4
   SonstigeThe layers were separated
5. 5
   ExtraktionThe aqueous layer was extracted with ether (2×75 mL)
6. 6
   WaschenThe combined ether phases were washed with 50 mL of brine
7. 7
   Trocknendried over MgSO4
8. 8
   SonstigeEvaporation of the solvent
9. 9
   workup.WAITleft 9.17 g of orange oil
10. 10
    SonstigeThe oil was chromatographed on a 700 g column of silica gel
11. 11
    WaschenThe column was eluted with 1:2 CH2Cl2 -Skellysolve B and 200 mL fractions
12. 12
    Sonstigewere collected

Vorschrift

To a solution of 0.8 g (3.03 mmoles) of 18-crown-6 in 100 mL of dry ether was added 4.39 g (39.12 mmoles) potassium tert-butoxide. The mixture was stirred while 5.08 g (33.51 mmoles) of 5-chloroindole was added. The stirring was continued for 0.5 hour. Most of the solid dissolved. Then 6.69 g (39.11 mmoles) of benzyl bromide in 40 mL of ether was added during 0.5 hours. The stirring was continued for 27 hours. Water (100 mL) was added. The layers were separated. The aqueous layer was extracted with ether (2×75 mL). The combined ether phases were washed with 50 mL of brine and dried over MgSO4. Evaporation of the solvent left 9.17 g of orange oil. The oil was chromatographed on a 700 g column of silica gel. The column was eluted with 1:2 CH2Cl2 -Skellysolve B and 200 mL fractions were collected. The fractions were assayed by silica gel tlc (2×8") (1:2 CH2Cl2 -Skellysolve B). Fractions 10-14 were combined giving 7.26 g (90%) of 1-benzyl-5-chloroindole as a yellow oil.

Quelle