A process is provide for the preparation of compounds of formula (I) herein ##STR1## comprising reacting a compound of formula (III), (IV) or (V) ##STR2## wherein the variables are as defined in the specification. The reaction is conducted in the presence of .sup.- OR.sup.3 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.
This application is filed claiming priority from co-pending U.S. Provisional Application Nos. 60/276,532 filed Mar. 16, 2001 and 60/292,378 filed May 21, 2001.
![Process for the preparation of pyrazolo[4,3-d]pyrimidin-7-one compounds and intermediates thereof - US Patent 6809200 - Page 1](http://www.wikipatents.com/process-for-the-preparation-of-pyrazolo43-dpyrimidin-7-one-compounds-and-intermediates-thereof/T/US6809200-1.jpg "Process for the preparation of pyrazolo[4,3-d]pyrimidin-7-one compounds and intermediates thereof - US Patent 6809200 - Page 1")
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