New pyrazolo[1′,5′:1,6]pyrimido[4,5-d]pyridazin-4(3H)-ones as potent and selective PDE5 inhibitors

New pyrazolo[1′,5′:1,6]pyrimido[4,5-d]pyridazin-4(3H)-ones as potent and selective PDE5 inhibitors 2-Phenylquinazolin-4(3H)-one, a class of potent PDE5 inhibitors with high selectivity versus PDE6 Quinazolines as potent and highly selective PDE5 inhibitors as potential therapeutics for male erectile dysfunction Substituted Pyrazolopyridopyridazines as Orally Bioavailable Potent and Selective PDE5 Inhibitors:  Potential Agents for Treatment of Erectile Dysfunction Novel Pyrazolopyrimidopyridazinones with Potent and Selective Phosphodiesterase 5 (PDE5) Inhibitory Activity as Potential Agents for Treatment of Erectile Dysfunction Pyrimidinylpyrroloquinolones as Highly Potent and Selective PDE5 Inhibitors for Treatment of Erectile Dysfunction Design and synthesis of pyrazolo[3,4-d]pyrimidinone derivatives: Discovery of selective phosphodiesterase-5 inhibitors 8-(3-Chloro-4-methoxybenzyl)-8H-pyrido[2,3-d]pyrimidin-7-one derivatives as potent and selective phosphodiesterase 5 inhibitors Optimization of purine based PDE1/PDE5 inhibitors to a potent and selective PDE5 inhibitor for the treatment of male ED Substituted Pyrazolopyridines as Potent and Selective PDE5 Inhibitors:  Potential Agents for Treatment of Erectile Dysfunction