Hydrochloric Acid → 6-Bromo-1-(3-methoxypropyl)-2-trifluoromethyl-1H-benzoimidazole

Participants

Reaction Steps

0.2 ml of concentrated aqueous hydrochloric acid is added under an argon atmosphere to a solution of 12.83 g of 4-bromo-N2-(3-methoxypropyl)benzene-1,2-diamine in 5.78 ml of trifluoroacetic acid. The reaction mixture is heated to reflux for 4 hours. 2 ml of trifluoroacetic acid are once again added and the reaction mixture is heated to reflux for a further 2 hours. The reaction mixture is cooled to room temperature and neutralized with saturated aqueous sodium hydrogencarbonate solution. The mixture is extracted with ethyl acetate (3×). The combined organic phases are dried over sodium sulphate and concentrated by evaporation. The title compound is obtained as a yellow oil from the residue by means of flash chromatography (SiO2 60F). Rf=0.60 (1:2 EtOAc-heptane). Rt=4.79 (gradient I).

Provenance & Evidence