Triphenylphosphine → 2-(9H-carbazol-2-yl)benzo[d]oxazole

Participants

Reaction Conditions

Reaction Steps

To a three-necked flask equipped with a magnetic stir bar and a condenser was added 2-(2′-nitrobiphenyl-4-yl)benzo[d]oxazole (1.08 g, 3.41 mmol, 1.0 eq) and PPh3 (4.48 g, 17.07 mmol, 5.0 eq). The flask was evacuated and back-filled with nitrogen. The evacuation and back-fill procedure was repeated twice. Then 1,2-dichlorobenzene (20 mL) was added under the protection of nitrogen. The mixture was stirred in an oil bath at a temperature of 175-185° C. for 24 hours, and cooled. The solvent was removed by distillation under high vacuum. Some ethyl acetate and dichloromethane was added to the residue and stirred at room temperature overnight. The residue was filtered and washed with dichloromethane. The collected solid was dried in air to get the desired product as an off-white solid 809 mg. 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 (117 mg in 96% total yield). 1H NMR (DMSO-d6, 400 MHz): δ 7.25 (t, J=7.6 Hz, 1H), 7.41-7.52 (m, 3H), 7.60 (d, J=8.4 Hz, 1H), 7.82-7.86 (m, 2H), 8.05 (dd, J=8.4, 1.2 Hz, 1H), 8.24 (d, J=7.2 Hz, 1H), 8.34-8.37 (m, 2H), 11.63 (s, 1H).

Provenance & Evidence