| 摘要 |
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.
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