Indole → 1-Benzylindole

HRID 1831856Notes

Reaction equation

HRID 1831856 reaction equation
N1[C:9]2[C:4](=C[CH:6]=[CH:7][CH:8]=2)C=C1.[CH2:10]1N2[CH2:16][CH2:17][N:12]([CH2:13][CH2:14]2)[CH2:11]1.[CH3:18][C:19](N(C)C)=O.[CH3:24][CH2:25]OC(C)=O>CCCC[N+](CCCC)(CCCC)CCCC.[Cl-].O>[CH2:13]([N:12]1[C:11]2[C:24](=[CH:25][CH:19]=[CH:18][CH:10]=2)[CH:16]=[CH:17]1)[C:14]1[CH:6]=[CH:7][CH:8]=[CH:9][CH:4]=1

Participants

7

Reactant 4

HCID 798IndoleHCID 8857Ethyl AcetateHCID 9237DabcoHCID 31374Dimethylacetamide

Product 1

HCID 969131-BenzylindoleYield 80%

Reagents, catalysts & solvents 2

HCID 70681Tetrabutylammonium ChlorideCatalystHCID 962WaterSolvent

Conditions

Temperature
135 °C

Procedure

To a mixture of indole (234 mg, 2.0 mmol), DBC (726 mg, 3.0 mmol), DABCO(67.2 mg, 0.6 mmol) and TBAC (556 mg, 2.0 mmol) is added DMA (4 mL). The resulting solution is heated at 135° C. for 2 h. The reaction mixture is cooled to RT and diluted with EtOAc (50 mL) and H2O (50 mL). The two layers are separated and the aqueous layer is back extracted with EtOAc (50 mL). The combined organic layers are washed with brine and dried over anhydrous Na2S04. The mixture is filtered and concentrated under vacuum. The crude residue is purified with Biotage Flash Chromatography unit on 40s cartridge eluting with hexane:CH2Cl2=19:1 solvent mixture to afford 1-benzylindole (about 331.2 mg, 80%) as a white solid: mp 43° C.; 1H NMR (CDCl3) δ 7.38 (m, 9H), 6.73 (d, 1H), 5.48 (s, 2H); 13C NMR (CDCl3) δ 137.5, 136.3, 128.7, 128.2, 127.6, 126.7, 121.6, 120.9, 119.5, 109.7, 101.6, 50.0; MS m/z 207.1043 [M+1]+.

Workup

  1. temperatureThe reaction mixture is cooled to RT
  2. customThe two layers are separated
  3. extractionthe aqueous layer is back extracted with EtOAc (50 mL)
  4. washThe combined organic layers are washed with brine
  5. customdried over anhydrous Na2S04
  6. filtrationThe mixture is filtered
  7. concentrationconcentrated under vacuum
  8. customThe crude residue is purified with Biotage Flash Chromatography unit on 40s cartridge
  9. washeluting with hexane

Sources & evidence

ORD record
ord-7793c8849084467cb9dff3241b8473fd
Source dataset
uspto-grants-2006_06
Patent number
US07067676B2

Reaction notes

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