Novel Synthesis of Antiobesity Drug Lorcaserin Hydrochloride

A novel synthesis of antiobesity drug lorcaserin hydrochloride was accomplished in six steps. N -protection of 2-(4-chlorophenyl)ethanamine with di- tert -butyl dicarbonate, N -alkylation with allyl bromide, deprotection, intramolecular Friedel–Crafts alkylation, chiral resolution with l -(+)-tartaric acid, and the final salification led to the target molecule lorcaserin hydrochloride in 23.1% overall yield with 99.9% purity and excellent enantioselectivity (>99.8% ee). This convenient and economical procedure is remarkably applicable for scale-up production.