Preparing pyrazolopyrimidinone derivatives for the treatment of impotence
US6844436B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 18, 2001 |
| Grant date | Jan 18, 2005 |
| Priority date | — |
| Expiry date | May 23, 2021 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D487/04
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.