Process for the preparation of pyrazolo[4,3-d]pyrimidin-7-one compounds and intermediates thereof

摘要

A process is provided for the preparation of compounds of formula (I) herein comprising reacting a compound of formula (II), (III), (IV) or (V) in the presence of -OR3 and a hydroxide trapping agent or in the case of compounds of formula (IV) reacting in the presence of an auxiliary base and a hydroxide trapping agent (i.e. -OR3 is substituted by the auxiliary base), wherein X is a leaving group and R1 to R4 are as defined.