Dimethylformamide → 3-(2-dimethylamino-ethyl)-1H-indole-5-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

To a solution of [2-(5-bromo-1H-indol-3-yl)ethyl]-dimethyl-amine (Example 3) (15 g, 56.1 mmol) in ether (450 mL), at −75° C. a solution of tert-butyl lithium (99 ml of 1.7 N solution in hexanes, 168 mmol) is added. The mixture is stirred for 50 minutes at −75° C., and then for 30 minutes at −30° C. To the obtained beige suspension, DMF (22.5 ml) is added during 15 minutes, and then the mixture is allowed to warm to ambient temperature. The mixture is poured on water and extracted with diethyl ether (500 mL). After washing the organic layer with brine (3 times 500 mL), and drying (sodium sulfate), removal of the solvent leaves the crude aldehyde, which is recrystallized, from toluene/hexane. Yield of the title compound: 9.9 g (81.8%) yellowish plates, mp=103° C. 1H-NMR (CDCl3, 300 MHz) δ 2.36 (s, 6H, N(CH3)2); 2.65-2.75 (m, 2H, CH2); 2.96-3.03 (m, 2H, CH2NMe2); 7.08 (d, 1H, 3J=2.7 Hz, H-2); 7.33 (d, 1H, 3J=8.4 Hz, H-7); 7.70 (dd, 1H, 4J=1.7 Hz, H-6); 8.13 (d, 1H, H-4); 8.74 (br s, 1H, NH); 10.02 (s, 1H, CHO). 13C-NMR (CDCl3, 75 MHz) δ 23.91 (CH2); 45.76 (CH3); 60.40 (CH2N); 111.85 (C-7); 116.68 (C-3); 122.87 (C-6); 123.61 (C-2); 124.04 (C-4); 127.68 (C-9); 129.35 (C-5); 140.06 (C-8); 192.56 (CHO).

Provenance & Evidence