Process for preparation of pyrazolo[4,3-D]pyrimidin-7-ones and intermediates thereof

摘要

A process is provided for the preparation of a compound of formulae (IA) (sidenafil/ ViagraTm TM ) and (IB) comprising reacting a compound of formula (IIA) and (IIB) respectively in the presence of <->OR, wherein R in the case of formation of compound (IA) is CH2CH3 and R in the case of formation of compound (IB) is CH2CH2CH3, where X is a leaving group: