The present invention relates to new 1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one compounds of formula (I), or a pharmaceutically acceptable salt or a stereoisomer thereof, useful for treatment of impotence diseases: ##STR1## wherein R.sub.1 and R.sub.2 may be the same or different and independently be C.sub.1-6 alkyl. The present invention also provides a method of preparing the compounds of formula (I).
This application is a continuation of the National Stage of International Application No. PCT/CN02/00433, filed on Jun. 21, 2002, which designated the United States and was published in Chinese, which claims the benefit of Chinese Patent Application No. 01129691.7 filed on Jun. 29, 2001, and Chines Patent Application No. 02100198.7 filed on Jan. 18, 2002. The entire teachings of the above applications are incorporated herein by reference.
Priority Data
Jun 29, 2001 [CN] 01129691 Jan 18, 2002 [CN] 02100198
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