N-3-substituted imidazoquinazolinones: Potent and selective PDE5 inhibitors as potential agents for treatment of erectile dysfunction

Phosphodiesterase type 5 (PDE5) inhibitors with improved PDE isozyme select ivity relative to sildenafil may result in agents for the treatment of male erectile dysfunction (MED) with a lower incidence of PDE-associated advers e effects. This paper describes the discovery of 14, a PDE5 inhibitor with improved potency and selectivity in vitro compared to sildenafil. This comp ound shows activity in a functional assay of erectile function comparable t o that of sildenafil.