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Three-Component Coupling (indole, aldehyde, amine); 4-[(2-methyl-1H-indol-3-yl)(1-phenylethylamino)methyl]benzene-1,3-diol

SyntheticPage 503
DOI: 10.1039/SP503
Submitted Aug 26, 2011, published Sep 05, 2011
Abir Kumar Pal (
A contribution from Dr. Reddys Laboratory, India

			Reaction Scheme: <img src="/images/empty.gif" alt="" />Three-Component Coupling (indole, aldehyde, amine)<img src="/images/empty.gif" alt="" />

Chemicals Used

2-methylindole (Lancaster)
3,4-dihydroxybenzaldehyde (Alfa Asar).
α-methylbenzylamine (Avra).
Trifluoroacetic acid


A mixture of 2-methylindole (0.1 g, 0.762 mmol), 2,4-dihydroxybenzaldehyde (0.105 g, 0.762 mmol), α-methylbenzylamine   (0, 09 mL, 0.726 mmol) and TFA  was stirred at room temperature for 4-5 h. After completion of the reaction (checked by TLC 40% ethyl acetate in Hexane Rf : 0.3) the reaction mass was quenched with 5% sodium bicarbonate solution (5 mL) and stirred for 1-2 h. A light brown solid was observed which was isolated by filtration and washed with hexane (5mL). The title compound was thus obtained as light brown color solid (0.19 g, 68%).

Author's Comments

The isolation proedure was very easy, and achieved higher yield in the bigger scale. On1 g scale 72% yield as achieved.


1H NMR (400 MHZ, DMSO-d6): δ 1.5 (3H, d), 2.0 (3H, s), 4.2 (1H, m), 4.8 (1H, s), 6.21 (2H, d), 6.75 (1H, d), 7.01 (2H, d), 7.5 (1H, m), 7.66 (2H, d), 7.8 (2H, d), 7.91 (1H, d), 7.93 (1H, d), 8.2 & 10.3 (2-OH, s), 8.93 & 13.9 (2-NH, bs).
(M+H): 373

Lead Reference

1. Tet. Lett., 2010,  51, 5701-5703: DOI: 10.1016/j.tetlet.2010.08.065
2. Synthesis, 2010, 6, 914-916; DOI: 10.1055/s-0029-1218637
3. Tet. Lett., 2009, 50, 3763-3766; DOI: 10.1016/j.tetlet.2009.02.176
4.  Monats. fuer Chem., 2004 ,135, 1265-1274;  DOI: 10.1007/s00706-004-0206-6

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Get structure file (.cdx, .sk2, .mol)

Keywords: 3-amino alkylated indole, aldehydes, amination, amines, heterocyclic compounds, nucleophilic

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