Kumar, Rajesh; Joshi, Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 2007, vol. 46, # 12, p. 2021 - 2025
作者:Kumar, Rajesh、Joshi
DOI:——
日期:——
PROCESS FOR THE PREPARATION OF SILDENAFIL AND INTERMEDIATES THEREOF
申请人:Tian Guanghui
公开号:US20100048897A1
公开(公告)日:2010-02-25
The present invention discloses a process for preparing sildenafil and its intermediates having the structures outlined below:
In particular, the present invention provides a process for preparing the compound of formula (I) and its intermediates, i.e. the compounds of formula (I), (II), (III) and (IV). The compound of formula (I) is obtained from the compound of formula (II); the compound (II) is obtained from the compound of formula (III) and methylpiperazine; the compound (III) is obtained by treating the compound of formula (IV) with chlorosulfonic acid; the compound (IV) is obtained though treating the compound of formula (V) in the presence of at least one selected from POX
3
, PX
3
, PX
5
and their mixtures in any ratio. The process for preparing the compound of formula (I) according to the present invention reduces the side reactions in the processes of the prior art. These improvements lead to higher yields and a better industrial applicability with easier controlling of the reaction.