申请人:Puig Torres Salvador
公开号:US20050124650A1
公开(公告)日:2005-06-09
The invention relates to a process for preparing granisetron, or a pharmaceutically acceptable salt thereof, which comprises: a) cyclisation of a compound of formula (I) in an inert solvent and at a temperature between 0-100° C., in the presence of a strong acid, in order to yield the compound of formula (II); b) methylation of the compound of formula (II), with an alkylating agent, in the presence of a base, in an inert solvent and at a temperature between 0° C.-160° C., and with optional formation of a pharmaceutically acceptable salt. The process of the invention yields a granisetron of high purity, preventing impurities due to demethylation, by carrying out the methylation after rather than before cyclisation and with a higher yield.
本发明涉及一种制备格拉司琼或其药学上可接受的盐的工艺,该工艺包括: a) 在惰性溶剂中,在强酸存在下,在 0-100 摄氏度的温度下,对式 (I) 化合物进行环化反应,以得到式 (II) 化合物; b) 在碱存在下,用烷基化剂对式 (II) 化合物进行甲基化反应、b) 在惰性溶剂中,在碱存在下,在 0° C.-160° C.的温度下,用烷基化剂将式 (II) 化合物甲基化,并可选择生成药学上可接受的盐。本发明的工艺通过在环化后而不是环化前进行甲基化,可以得到高纯度的格拉司琼,避免了因脱甲基化而产生的杂质,而且产率较高。