The present invention relates to an improved process for the preparation of compound of formula (I), 8-chloro-6,11-dihydro-11-(4-piperidinylidene)-5H-benzo[5,6]cyclohepta[1,2-b]pyridine (Desloratadine) or its pharmaceutically acceptable salts thereof, by reacting a compound of formula (II), 4-(8-Chloro-5,6-dihydro-11H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-ylidene)-1 piperidinecarboxylic acid ethyl ester (Loratadine) with sodium hydroxide in a solvent mixture of toluene and polyethylene glycol (PEG 400) at reflux temperature.
本发明涉及一种改进的制备式(I)化合物的方法,即8-
氯-6,11-二氢-11-(4-
哌啶烯基)-5H-苯并[5,6]环庚[1,2-b]
吡啶(右旋雷贝林)或其药学上可接受的盐,通过在
甲苯和聚
乙二醇(P
EG 400)的溶剂混合物中,将式(II)化合物,即4-(8-
氯-5,6-二氢-11H-苯并[5,6]环庚[1,2-b]
吡啶-11-基烯基)-
1-哌啶羧酸乙酯(左旋雷贝林),与
氢氧化钠在回流温度下反应。