Hydrochloric Acid → 1-[2-(4-Fluoro-1H-benzoimidazol-2-yl)-ethyl]-piperidine-4-carboxylic acid ethyl ester

Beteiligte Stoffe

Reaktionsschritte

A solution of (a) (6.4 g, 30 mmol) and ethanol (2.1 ml, 40 mmol) in chloroform (60 ml) was saturated with gaseous hydrochloric acid at 0° C. for 0.5 hours. The mixture was left 20 hours at 4° C. then concentrated in vacuo to afford a white foam. This was suspended in chloroform (60 ml), treated with 3-fluorophenylenediamine (3.8 g, 30 mmol) and heated under reflux for 1 hour. The mixture was poured onto water. The aqueous phase was then basified with sodium bicarbonate and extracted three times with dichloromethane. The organic extract was washed with water, brine, dried over magnesium sulfate and evaporated. The resulting residue was triturated with ethyl acetate, then diethyl ether to give a white solid (5.2 g, 55%).

Herkunft & Nachweise