Phosphoric Acid → 8-Bromo-5-fluoro-2-propylquinoline

Participants

Reaction Conditions

Reaction Steps

2-Bromo-5-fluoro-aniline (5.00 g, 95 mass % article, 25.0 mmol), m-nitrobenzenesulfonic acid (2.65 g, 13.0 mmol), 20.0 mL of 85 wt % aqueous phosphoric acid solution and ferrous sulfate heptahydrate (65.5 mg, 0.250 mmol) were placed in a 100 mL three-neck flask equipped with a magnetic stirrer, a reflux condenser, a thermometer and a dropping funnel and the mixture was heated to 80° C. in an oil bath. Subsequently, trans-2-hexenal (6.51 g, 98 mass % article, 65.0 mmol) was added dropwise thereto through the dropping funnel for 1 hour. After completion of the dropwise addition, the mixture was heated and stirred at 100° C. for 2 hours. Then, the reaction mixture was poured into water and neutralized to pH 7 by ammonia water. The neutralized liquid was extracted with dichloromethane, and then dichloromethane was removed under reduced pressure. The resulting crude reaction product was purified by column chromatography (Hexane/AcOEt=100/0→1/10) using silica gel, followed by drying under reduced pressure to give 625 mg of 8-bromo-5-fluoro-2-propylquinoline as a yellowish white solid (yield: 9.33%).

Provenance & Evidence