Methane → Ethyl 1,2,3,6-tetrahydroazepino[4,5-B]indole-5-carboxylate

Participants

Reaction Steps

A mixture of tryptamine hydrochloride (1.96 g, 10 mmol), ethyl 3-bromopyruvate (1.67 mL, 1.2 equiv) and decolorizing charcoal (0.5 g) in absolute ethanol was heated to reflux under nitrogen overnight. TEA was added and the reaction mixture was heated to reflux for another 7.5 hours. After cooling, charcoal was removed by filtration and washed with ethanol. The filtrate was concentrated under vacuum and diluted with water (20 mL). It was then extracted by EtOAc (3×30 mL) and the combined organic layers were washed with brine and dried over MgSO4. Evaporation of solvent and recrystallization from DCM-Hexane gave the title compound (1.17 g). 1H-NMR (CDCl3): δ 10.49 (1 H, br s), 7.79 (1H, d), 7.43 (1H, d), 7.43 (1 H, d), 7.06 (2H, m), 5.27 (1H, br s), 4.29 (2H, q) 3.58 (2H, m), 3.17 (2H, m), 1.36 (3H, t); MS (ES): 257 (MH+).

Provenance & Evidence