Boron tribromide → 4-Chloro-2-pyridazin-4-ylphenol

Beteiligte Stoffe

Reaktionsschritte

To a stirred solution of 4-(5-chloro-2-methoxyphenyl)pyridazine (Preparation 6, 22 g, 100 mmol) in dichloromethane (200 mL) at 0° C. was added drop wise a solution of boron tribromide (48 mL, 499 mmol) in dichloromethane (200 mL). The reaction mixture was stirred at room temperature for 18 hours. The reaction was quenched by pouring onto crushed ice and basifying the mixture to pH 8 with sodium hydrogen carbonate. The mixture was extracted with dichloromethane. The aqueous layer was extracted further with ethyl acetate. The organics were combined and dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The crude residue was purified by silica gel column chromatography (0%-4% methanol in dichloromethane gradient elution) to afford the title compound (16.5 g, 80%)

Herkunft & Nachweise