Dong-a Pharm. Co., Ltd.

Eun-Ha Kim

Soon-Hoe Kim

Dong-Sung Kim

Yong-duck Kim

Moo-Hi Yoo

Won-Bae Kim

Min-Sun Chang

Chul-Jun Bae

Yong-Duck Kim

A method for preparing pyrazolopyrimidinone derivatives and their pharmaceutically acceptable salts having efficacy on the treatment of impotence, one of male sexual dysfunctions. The method comprises the steps of: a) chlorosulfonating a pyrazolamide compound to obtain a chlorosulfonated compound; b) reacting the chlorosulfonated compound of step (a) with a primary amine to obtain a sulfonamide compound and c) performing an intramolecular cyclization of the sulfonamide compound of step (b) to produce the compound of formula below 1, wherein the steps b) and c) are performed in situ in alcohol by adding a base to the reaction mixture without workup after the step b) is completed.

Preparing pyrazolopyrimidinone derivatives for the treatment of impotence

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Sungnam-si, South Korea

Eun-Ha Kim