Aluminium lithium hydride → 4-Bromo-3-(2,3-dihydro-indol-1-ylmethyl)-benzylamine
Reaction equation
[Br:1][C:2]1[CH:9]=[CH:8][C:5]([C:6]#[N:7])=[CH:4][C:3]=1[CH2:10][N:11]1[C:19]2[C:14](=[CH:15][CH:16]=[CH:17][CH:18]=2)[CH2:13][CH2:12]1.[H-].[Al+3].[Li+].[H-].[H-].[H-]>O1CCCC1>[Br:1][C:2]1[CH:9]=[CH:8][C:5]([CH2:6][NH2:7])=[CH:4][C:3]=1[CH2:10][N:11]1[C:19]2[C:14](=[CH:15][CH:16]=[CH:17][CH:18]=2)[CH2:13][CH2:12]1Participants
4
Procedure
The crude 4-bromo-3-(2,3-dihydro-indol-1-ylmethyl)-benzonitrile (3.04 g) dissolved in dry tetrahydrofuran (50 mL) was dropped to an ice-cold slurry of lithium aluminium hydride 4.16 g, 0.11 mmol) in dry tetrahydrofuran (50 mL). The mixture was stirred for 1 h at ambient temperature, and then heated at reflux for another hour. The flask was cooled on ice, and the reaction mixture quenched with water (4.2 mL) followed by 15% NaOH(aq) (4.2 mL). Additional water (12.6 mL) was added and the mixture stirred at ambient temperature for 1 h. The white precipitate was filtered and washed with tetrahydrofuran. Evaporation afforded crude 4-bromo-3-(2,3-dihydro-indol-1-ylmethyl)-benzylamine (3.20 g) as a yellow oil. This was stirred together with ethyl trifluoroacetate (2.5 ml, 20.9 mmol) in dry methylene chloride (50 mL) for 17 h at room temperature. Evaporation followed by chromatography (ethyl acetate/heptane: 25/75) gave the sub-title compound.