Indole → 1-Benzylindole

HRID 488538

Reaction equation

HRID 488538 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 Na2SO4. The mixture is filtered and concentrated under vacuum. The crude residue is purified with Biotage Flash Chromatography unit on 40 s 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) δ7.38 (m, 9H), 6.73 (d, 1H), 5.48 (s, 2H); 13C NMR (CDCl3) δ137.5, 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. dry with materialdried over anhydrous Na2SO4
  6. filtrationThe mixture is filtered
  7. concentrationconcentrated under vacuum
  8. customThe crude residue is purified with Biotage Flash Chromatography unit on 40 s cartridge
  9. washeluting with hexane

Sources & evidence

ORD record
ord-da8e818df7b34bd69a9e779ff363a5cb
Source dataset
uspto-grants-2005_12
Patent number
US06972336B2

Linked notes

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