C1OCCOCCOCCOCCOCCOC1.CC(C)([O-])C.[K+].[Cl:25][C:26]1[CH:27]=[C:28]2[C:32](=[CH:33][CH:34]=1)[NH:31][CH:30]=[CH:29]2.[CH2:35](Br)[C:36]1[CH:41]=[CH:40][CH:39]=[CH:38][CH:37]=1>CCOCC.O>[CH2:35]([N:31]1[C:32]2[C:28](=[CH:27][C:26]([Cl:25])=[CH:34][CH:33]=2)[CH:29]=[CH:30]1)[C:36]1[CH:41]=[CH:40][CH:39]=[CH:38][CH:37]=1To 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.
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