A Concise Synthesis of Tetrabenazine and Its Crystal Structure

Abstract

The title compound tetrabenazine was synthesized by reaction of 3-dimethyl-aminomethylheptan-2-one and 6,7-dimethoxy-3,4-dihydroisoquinoline hydrochloride. This approach provides an efficient and concise way to the synthesis of the marketed drug tetrabenazine. The colorless single crystal of tetrabenazine suitable for X-ray analysis was obtained from saturated methanol solution. The X-ray results showed that tetrabenazine consists of (3R, 11bR) and (3S, 11bS) enantiomers. Two terminal methyl groups are disordered in the (3R, 11bR) enantiomer.