A two-step process to synthesize racemic lorcaserin was developed from 2-(4-chlorophenyl)ethanol via formation of bromide or tosylate derivatives. These derivatives were reacted with allylamine in neat conditions to provide pure N-(4-chlorophenethyl)allylammonium chloride. This compound was cyclized in neat conditions using aluminum or zinc chloride to give racemic lorcaserin. After resolution of enantiomers, the wrong enantiomer was racemized and recycled to give new R-lorcaserin.

中文翻译：

---

氯酪蛋白新合成工艺的开发和优化

通过形成溴化物或甲苯磺酸酯衍生物，由2-（4-氯苯基）乙醇开发出了两步合成外消旋氯酪蛋白的方法。这些衍生物在纯净条件下与烯丙胺反应，得到纯的N-（4-氯苯乙基）烯丙基氯化铵。该化合物在纯净的条件下使用氯化铝或氯化锌环化，得到外消旋氯酪蛋白。拆分对映异构体后，将错误的对映异构体消旋并回收，得到新的R-氯酪蛋白。