Water → 1-(pentan-2-yl)-1H-indole-4-carbaldehyde

HRID 2176808Notes

Reaction equation

[NH:1]1[C:9]2[CH:8]=[CH:7][CH:6]=[C:5]([CH:10]=[O:11])[C:4]=2[CH:3]=[CH:2]1.CC(C)([O-])C.[K+].Br[CH:19]([CH2:21][CH2:22][CH3:23])[CH3:20].O>CN(C)C=O.C(OCC)(=O)C>[CH3:20][CH:19]([N:1]1[C:9]2[CH:8]=[CH:7][CH:6]=[C:5]([CH:10]=[O:11])[C:4]=2[CH:3]=[CH:2]1)[CH2:21][CH2:22][CH3:23]

Participants

Conditions

Temperature: 0 °C

Procedure

To a solution of 1H-indole-4-carbaldehyde (1) (1.0 g, 6.88 mmol) in dimethylformamide (DMF, 35 mL) was added potassium t-butoxide (KOtBu, 1.16 g, 10.32 mmol) at 0° C. After the resulting solution was stirred for 30 min at 0° C., 2-bromopentane (2) (1.05 ml, 8.27 mmol) was added dropwise, and the reaction solution was warmed up to room temperature gradually and stirred for 12 h at room temperature. Water (5 ml) was added to quench the reaction. The reaction mixture was diluted with ethyl acetate (50 mL) and washed with H2O (40 mL). The organic layer was dried over Na2SO4, filtered, and concentrated in vacuo. Purification by flash chromatography (6:1 hexane/ethyl acetate) recovered 1H-indole-4-carbaldehyde (1) (500 mg) and gave 1-(pentan-2-yl)-1H-indole-4-carbaldehyde (3) mixed with residual 2-bromopentane (2), which was used in the following step directly.

Workup

temperaturethe reaction solution was warmed up to room temperature gradually
stirringstirred for 12 h at room temperature
customto quench
customthe reaction
washwashed with H2O (40 mL)
dry with materialThe organic layer was dried over Na2SO4
filtrationfiltered
concentrationconcentrated in vacuo
customPurification by flash chromatography (6:1 hexane/ethyl acetate)
customrecovered 1H-indole-4-carbaldehyde (1) (500 mg)

Sources & evidence

ORD record: ord-c2b122b50a314509aa65a041ae5508a0
Source dataset: uspto-grants-2015_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09067886B2

Reaction notes

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