Carbazole → 4-(2-Carbazol-9-yl-ethyl)benzoic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

Carbazole (0.50 g, 2.99 mmol) and sodium hydride (60 wt. % in mineral oil, 0.14 g, 3.59 mmol) were placed under argon and dissolved in 6 mL of anhydrous DMF at room temperature, giving a dark brown solution. Following the evolution of hydrogen gas, 4-(2-bromo-ethyl)benzoic acid methyl ester (26) (0.73 g, 2.99 mmol) in DMF (2 mL) was added and the reaction was stirred at 70° C. for 2 h. The mixture was taken up in ethyl acetate (30 mL) and water (30 mL), the organic layer was separated and the aqueous layer extracted with ethyl acetate (2×10 mL). The combined organic layers were washed with brine (2×25 mL), dried (Na2SO4) and concentrated in vacuo. The residue was purified by MPCC(C18, 10-100% gradient of MeOH in H2O). The product co-eluted with unreacted carbazole. Cold MeOH (8 mL) was added to the product mixture and the suspension was filtered to remove the solid carbazole. The filtrate was concentrated to give the title compound (291 mg, 43%) as a red solid. 1H NMR (400 MHz, CDCl3): δ 8.11 (m, 2H), 7.92 (d, 2H, J=8.0 Hz), 7.43 (m, 2H), 7.30 (m, 2H), 7.25 (m, 4H), 4.55 (t, 2H, J=7.3 Hz), 3.91 (s, 3H), 3.20 (t, 2H, J=7.4 Hz). 13C NMR (100 MHz, CDCl3): δ 167.0, 144.1, 140.1, 123.0, 128.9, 125.8, 122.9, 120.4, 119.4, 110.6, 108.4, 52.1, 44.4, 35.2. ESI-HRMS (m/z): [M+H]+ calcd. for C22H19NO2, 330.1489. found, 330.1460.

Provenance & Evidence