1,2,3,4-Tetrahydrocarbazole → 6-(1,2,3,4-Tetrahydrocarbazol-9-yl)hexanoic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

A RB flask fitted with reflux condenser containing tetrahydrocarbazole (1.71 g, 10.0 mol) was dissolved in DMSO (30 mL), treated with potassium tert-butoxide (1M solution in THF, 12 mL) and stirred at 110° C. for 20 min. Ethyl 6-bromohexanoate (1.67 mL, 10.0 mmol) was added and the mixture stirred at 110° C. for 60 min. The reaction was quenched with a 1:1 brine:water solution (120 mL) and extracted with ethyl acetate. The combined organic extracts were washed with brine, dried (Na2SO4) and concentrated. Purification by column chromatography (25% ethyl acetate in hexane) afforded the title compound (1.01 g, 32%). 1H NMR (400 MHz, CDCl3): δ 7.52 (m, 1H), 7.27 (m, 1H), 7.19 (m, 1H), 7.12 (m, 1H), 4.18 (q, 2H, J=7.1 Hz), 4.04 (t, 2H, J=7.4 Hz), 2.78-2.73 (m, 4H), 2.33 (t, 2H, J=7.5 Hz), 2.00-1.92 (m, 4H), 1.80-1.75 (m, 2H), 1.72-1.66 (m, 2H), 1.42 (m, 2H), 1.30 (t, 3H, J=6.9 Hz). ESI-HRMS (m/z): [M+H]+ calcd. for C20H27NO2, 314.2115. found, 314.2103.

Provenance & Evidence