Hydrochloric Acid → 3-[1-(1-Methyl-piperidin-4-yl)-indol-3-yl]-4-(1-methyl-indol-3-yl)-1H-pyrrole-2,5-dione hydrochloride

Participants

Reaction Steps

An ice cooled solution of 3-[1-(1-methyl-piperidin-4-yl)-1H-indol-3-yl]-4-(1-methyl-1H-indol-3-yl)-pyrrole-2,5-dione (70 g, 0.16 mol) in ethyl acetate (4 L) was saturated with gaseous hydrogen chloride for 3 hours. The precipitate formed was isolated by suction filtration, suspended in methanol (3 L) and stirred for 30 minutes. The mixture turned into a homogenous slurry, which was concentrated and treated with ether (500 mL). The title compound crystallized and was collected by suction filtration. The filter was vacuum dried over night (100° C./0.1 mm. Yield 70 g (92% of theory). M.Pt.: 280°-282° C.

Provenance & Evidence