Potassium Phosphate, Tribasic → 2-(3-(quinolin-2-yl)phenoxy)-9H-carbazole

Participants

Reaction Conditions

Reaction Steps

3-(quinolin-2-yl)phenol (3.68 g, 15.30 mmol, 1.0 eq), 4′-iodo-2-nitrobiphenyl (5.97 g, 18.36 mmol, 1.2 eq), CuI (0.15 g, 0.77 mmol, 0.05 eq), picolinic acid (0.19 g, 1.53 mmol, 0.1 eq) and K3PO4 (6.50 g, 30.60 mmol, 2.0 eq) were added to a dry pressure vessel equipped with a magnetic stir bar. The vessel was evacuated and back-filled with nitrogen. The evacuation and back-fill procedure was repeated twice. Then solvent DMSO (32 mL) was added under nitrogen. After bubbling with nitrogen for 20 minutes, the mixture was heated to 80-90° C. in an oil bath. The reaction was monitored by TLC and about 22 hours later the starting material 3-(quinolin-2-yl)phenol was consumed completely. Then the mixture was cooled to ambient temperature and diluted with water, extracted with ethyl acetate three times. The combined organic layer was washed with water three times and dried over sodium sulfate, and filtered and washed with ethyl acetate. The filtrate was concentrated and the residue was purified through column chromatography on silica gel using hexane and ethyl acetate (10:1-5:1-3:1) as an eluent to obtain the desired product as a sticky brown liquid (5.98 g), which was used directly for the next step. A solution of PPh3 (11.19 g, 42.6 mmol) and the sticky brown liquid (5.95 g) obtained in the last step in 1,2-dichlorobenzene (28.4 mL) was stirred at a temperature of 175-185° C. in oil bath and for 21 hours under nitrogen, cooled and the solvent was removed by distillation under high vacuum. The residue was purified through column chromatography on silica gel using hexane and ethyl acetate (10:1-5:1-3:1) as an eluent to obtain the desired product 2-(3-(quinolin-2-yl)phenoxy)-9H-carbazole, which was further purified through recrystallization in ethyl acetate and hexane to get pure product as a white solid (4.45 g) in 75% total yield for the four steps. 1H NMR (DMSO-d6, 400 MHz): δ 6.96 (dd, J=8.4, 2.4 Hz, 1H), 7.13 (d, J=2.4 Hz, 1H), 7.16 (d, J=7.6 Hz, 1H), 7.21 (dd, J=8.4, 2.4 Hz, 1H), 7.35 (d, J=8.0 Hz, 1H), 7.46 (d, J=8.0 Hz, 1H), 7.57-7.61 (m, 2H), 7.74-7.77 (m, 1H), 7.99-8.03 (m, 3H), 8.05-8.09 (m, 2H), 8.14 (d, J=5.6 Hz, 1H), 8.16 (d, J=5.2 Hz, 1H), 8.46 (d, J=9.2 Hz, 1H), 11.23 (s, 1H).

Provenance & Evidence