Cesium carbonate → 3-[5-(2-Piperidin-1-yl-ethoxy)-1H-indol-2-yl]-1H-quinolin-2-one

Participants

Reaction Conditions

Reaction Steps

A mixture of tert-butyl 2-(2-chloro-3-quinolinyl)-5-hydroxy-1H-indole-1-carboxylate 1-8 (395 mg, 1.00 mmol, 1 equiv), 1-(2-chloroethyl)-piperidine hydrochloride (276 mg, 1.50 mmol, 1.50 equiv), and cesium carbonate (978 mg, 3.00 mmol, 3.00 equiv) in N,N-dimethylformamide (5 mL) was heated at 50° C. for 2 hours. The reaction mixture was concentrated, and the residue was partitioned between water and ethyl acetate. The organic layer was washed with water then brine, dried over magnesium sulfate, and concentrated to give a pale-yellow foam. The foam was dissolved in a 1:1 mixture of water and acetic acid (60 mL), and the resulting solution was heated at 110° C. for 12 hours. The reaction mixture was concentrated, and the residue was stirred in aqueous saturated sodium bicarbonate solution which yielded a tan solid. The tan solid was filtered, then suspended in warm ethanol (2×20 mL) and filtered to give 3-[5-(2-piperidin-1-yl-ethoxy)-1H-indol-2-yl]-1H-quinolin-2-one (1-9) as a yellow solid. The ethanolic filtrate was concentrated and the residue purified by flash column chromatography (5% ethanol saturated with ammonia in ethyl acetate to afford additional 1-9. 1H NMR (400 MHz, (CD3)2SO) δ 12.14 (s, 1H), 11.41 (s, 1H), 8.50 (s, 1H), 7.73 (br d, 1H, J=7.9 Hz), 7.51 (br t, 1H, J=7.6 Hz), 7.41 (d, 1H, J=8.6 Hz), 7.37 (br d, 1H, J=8.2 Hz), 7.24 (br t, 1H, J=7.7 Hz), 7.21 (br s, 1H), 7.06 (br s, 1H), 6.76 (dd, 1H, J=8.6, 2.2 Hz), 4.06 (t, 2H, J=5.9 Hz), 2.67 (t, 3H, J=5.5 Hz), 2.45 (br m, 4H), 1.51 (br m, 4H), 1.39 (br m, 2H).

Provenance & Evidence