The antidepressant drug Escitalopram is prepared from 5-bromophthalide via the diol intermediate (4-bromo-2-(hydroxymethyl)phenyl)-(4-fluorophenyl)methanol. The racemic diol intermediate is converted to an enantiomerically enriched form by first converting the diol to a monoester intermediate and then reacting the monoester intermediate with an optically active acid, most preferably (+)-di-p-toluoyl tartaric acid, to form a salt. The salt is then crystallized to recover an enantiomerically enriched, crystalline form thereof. The monoester intermediate is preferably formed by reacting the racemic diol intermediate with an acid or a reactive acid derivative which, in a particularly preferred embodiment, is acetic anhydride.
抗抑郁药埃司
西酞普兰是通过从5-
溴邻苯二酮经过二醇中间体(4-
溴-2-(羟甲基)苯基)-(4-
氟苯基)
甲醇制备而成的。外消旋二醇中间体首先转化为富集对映体形式,方法是先将二醇转化为单酯中间体,然后将单酯中间体与光学活性酸反应,最好是(+)-二
对甲苯基酒石酸,形成盐。然后结晶盐以回收其富集对映体、结晶形式。单酯中间体最好是通过将外消旋二醇中间体与酸或反应性酸衍
生物反应形成的,特别优选的是
乙酸酐。