An Alternative Approach to Synthesize Sildenafil via Improved Copper-Catalyzed Cyclization
A facile synthetic pathway for sildenafil has been developed. This approach is characterized by a ligand-free Ullmann-type copper-catalyzed coupling reaction to construct sildenafil and its derivative, pyrrazolo[4,3-d]pyrimidin-7-one ring, with yields of 79% and 82%, respectively, in a convergent...
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Veröffentlicht in: | Journal of organic chemistry 2024-05, Vol.89 (10), p.7303-7311 |
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Hauptverfasser: | , , , , , , |
Format: | Artikel |
Sprache: | eng |
Online-Zugang: | Volltext |
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Zusammenfassung: | A facile synthetic pathway for sildenafil has been developed. This approach is characterized by a ligand-free Ullmann-type copper-catalyzed coupling reaction to construct sildenafil and its derivative, pyrrazolo[4,3-d]pyrimidin-7-one ring, with yields of 79% and 82%, respectively, in a convergent fashion by connecting key building blocks halo-pyrazole moiety 16c with 2-ethoxybenzamidine and 2-ethoxy-5-[(4-methylpiperazin-1-yl)sulfonyl]benzamidine in a one-pot reaction. Thus, this approach circumvents the need to use nitric/sulfuric acid for nitration, a costly Pd-catalyst for reduction, and coupling agents encountered in the reported processes. |
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ISSN: | 0022-3263 1520-6904 |
DOI: | 10.1021/acs.joc.4c00393 |