反应详情

Hydrogen chloride gas was passed through a solution of 4-methoxy-2-propoxy-benzonitrile (280 mg, 1.464 mmol) in anhydrous ethanol (20 mL) at 0° C. After 1 h, hydrogen chloride gas was stopped and the reaction vessel was sealed with a stopper. After stirring at room temperature for 2 d, the reaction vessel was cooled to 0° C. and the stopper was removed. The solvent was evaporated in vacuo and the residue was triturated in diethyl ether to afford crude ethyl 4-methoxy-2-propoxy-benzimidate hydrochloride. It was dissolved in ethanol (10 mL), and meso-1,2-bis-(4-chloro-phenyl)-ethane-1,2-diamine (412 mg, 1.464 mmol) and triethylamine (308 μL, 2.194 mmol) were added. The reaction mixture was heated at reflux for 4 h. The solvent was removed and the residue was taken up in methylene chloride (2 mL) and sodium bicarbonate solution (2 mL). The product was extracted with methylene chloride (2×20 mL). The organic layers were washed with brine (1×5 mL) and dried over anhydrous sodium sulfate. The solid was then filtered off, and the filtrate was concentrated in vacuo. The residue was purified by flash chromatography (Biotage system, KP-Sil™ 32-63 μm, 60 Å silica gel) eluting with 70% ethyl acetate in hexanes to afford 4,5-bis-(4-chloro-phenyl)-2-(4-methoxy-2-propoxy-phenyl)-4,5-dihydro-1H-imidazole (303 mg, 46%). HR-MS (ES, m/z) calculated for C25H25N2O2Cl2 [(M+H)+] 455.1288, observed 455.1293.

1. customthe reaction vessel was sealed with a stopper
2. temperaturethe reaction vessel was cooled to 0° C.
3. customthe stopper was removed
4. customThe solvent was evaporated in vacuo
5. customthe residue was triturated in diethyl ether