The present invention relates to a novel racemic or optically active carbamate intermediate of formula (IV A). This novel racemic or optically active carbamate intermediate of formula (IV A) can be used to prepare drugs having antihistaminic activity such as cetirizine (IA), meclizine (IB), chlorcyclizine (IC), clocinizine (ID), buclizine (IE) and enantiomers thereof such as levocetirizine (I). Further, disclosed herein is an improved process for the preparation of levocetirizine via a novel optically active intermediate i.e. compound of formula (IV). Also, disclosed herein is a novel process for the preparation of compound (II) and for crystallization of its salt.
本发明涉及一种新型的外消旋或光学活性碳酰胺中间体,其
化学式为(IV A)。这种新型的外消旋或光学活性碳酰胺中间体(IV A)可用于制备具有抗
组胺活性的药物,例如
西替利嗪(IA)、美克酸赛(IB)、
氯环嗪(IC)、
氯西嗪(ID)、布克利嗪(IE)及其对映体,例如
左西替利嗪(I)。此外,本文还公开了一种通过一种新型的光学活性中间体即
化学式(IV)的化合物来制备
左西替利嗪的改进工艺。同时,还公开了化合物(II)的制备方法及其盐的结晶工艺。