Dimethylformamide → 3-[3-(4-Methylpiperazin-1-yl)-propyl]-4,5,6,7-tetrahydro-1H-indole-2-carbaldehyde

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Reaction Steps

Phosphorus oxychloride (1.8 mL, 18.9 mmol) was added dropwise to cooled dimethylformamide (3.8 mL, 51.6 mmol). After stirring at room temperature for 30 minutes, it was cooled to −5° C. and a solution of 3-[3-(4-methyl-piperazin-1-yl)-propyl]-4,5,6,7-tetrahydro-1H-indole (4.5 g, 17.2 mmol) in dimethylformamide (9 mL) was added dropwise. The mixture was stirred at room temperature overnight. The reaction was quenched with ice, followed by 10 N sodium hydroxide to pH 10–11. After stirring at room temperature for 1 hour, the reaction was extracted with ethyl acetate, washed with brine, dried and concentrated to give 3.1 g (62% yield) of 3-[3-(4-methyl-piperazin-1-yl)-propyl]-4,5,6,7-tetrahydro-1H-indole-2-carbaldehyde. 1H-NMR (360 MHz, diemthylsulfoxide-d6) δ 11.24 (br, s, 1H, NH), 9.42 (s, 1H, CHO), 2.60 (t, 2H, CH2), 2.51 (m, 2H, CH2), 2.35 (m, 2H, CH2), 2.28 (m, 8H, 4×CH2), 2.21 (m, 2H, CH2), 2.12 (s, 3H, CH3), 1.57–1.68 (m, 6H, 3×CH2). MS m/z 289 [M+].

Provenance & Evidence