Reacción #5692

Ecuación de reacción

5-chloroindole

benzyl bromide

18-crown-6

potassium tert-butoxide

→

1-benzyl-5-chloroindole

Rendimiento 90.0%

Disolventes

Water

ether

ether

Condiciones de reacción

Tratamiento posterior

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
   OtroThe layers were separated
5. 5
   ExtracciónThe aqueous layer was extracted with ether (2×75 mL)
6. 6
   LavadoThe combined ether phases were washed with 50 mL of brine
7. 7
   Secadodried over MgSO4
8. 8
   OtroEvaporation of the solvent
9. 9
   workup.WAITleft 9.17 g of orange oil
10. 10
    OtroThe oil was chromatographed on a 700 g column of silica gel
11. 11
    LavadoThe column was eluted with 1:2 CH2Cl2 -Skellysolve B and 200 mL fractions
12. 12
    Otrowere collected

Procedimiento

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.

Fuente