| 摘要 |
The present invention relates to a method for the preparation of mirtazap ine and tetracyclic analogous compounds having substantial enantiomeric exce ss of the R or S form. The invention further relates to a novel intermediate and its use for the preparation of mirtazapine having a substantial enantio meric excess of the R or S form. The method comprising the steps of a: provi ding a carboxylic acid compound according to Formula (I) having a substantia l enantiomeric excess of the R or S form, b: converting the carboxylic acid group of compound I into a ketone group, producing a ketone compound of Form ula (II), c: optionally reducing ketone compound II with a mild reduction ag ent to form the intermediate hydroxy compound of Formula (III) and d: formin g the mirtazapine of Formula (IV) by reduction of the ketone compound II or of the hydroxy compound III using a strong reduction agent.
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