Boron tribromide → Cis-2-(3,4-dihydroxybenzyl)-5-[2-(4-hydroxyphenyl)ethyl]pyrrolidine hydrobromide

Participants

Reaction Steps

To a cold solution of 3 g. (0.008 mole) of cis-2-(3,4-dimethoxybenzyl)-5-[2-(4-methoxyphenyl)ethyl]pyrrolidine hydrochloride in 50 ml. of methylene chloride was added dropwise 8 g. (0.032 mole) of boron tribromide at -60° C. After addition of boron tribromide was finished, the cold bath was removed, and the reaction mixture was gradually warmed up to room temperature over a period of about one and a half hours. The mixture was then cooled again in a Dry Ice-acetone bath and 25 ml. of methanol was carefully added. After methanol was completely removed, the residue was treated with ethyl acetate. Upon storing in a freezer, an off-white solid crystallized out, which was recrystallized from ethyl acetate and ethanol to give 3.11 g. of pure product, m.p. 195°-198° C.

Provenance & Evidence