الفهرس 
Title : Synthesis of some pyrazolo [3, 4-d] pyrimidin-4 (5H)-one derivatives of expected action on erectile dysfunction
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Abstract
This work includes a survey on the chemistry of pyrazolo [3,4-d]pyrimidine-4-(5H)-ones, methods of synthesis and their chemical reaction. Also it includes erectile dysfunction definition, its causes and treatment options. Moreover, this work covers phosphodiesterases (PDEs) types, their distribution, and their mechanism of action in the body, especially PDE5. It includes a review of PDE5 inhibitors, their role in treatment of ED, mechanism of action, classification, side effects, their SAR and other pharmacological uses beyond erectile dysfunction. This work includes design and synthesis of some pyrazolo[3,4-d] pyrimidin-4(5H)-one derivatives as sildenafil analogues for treatment of ED. This study includes the preparation of ten reported intermediates, two new intermediates and thirty-two final compounds present in three schemes. Scheme I: aimed to prepare compounds 1-(4-substitutedphenyl)-3-substituted-6-(2-substitutedphenyl)-1H-pyrazolo[3,4-d]pyrimidin-4(5H)- ones IVa- n and Va, b. In this scheme, malononitrile was refluxed with triethylorthoformate or acetate to afford 2-(ethoxyalkylidene) malono-nitrile Ia, b which was refluxed with 4-substituted phenylhydrazine to give 5-amino-1-(4-substitutedphenyl)- 3-substituted-1H-pyrazole-4-carbonitrile IIa-d. The resulting aminocyanopyrazole was treated with 2M sodium hydroxide to afford the corresponding carboxamide IIIa- d which inturn was coupled with 2-substituted benzaldehyde under reflux in acetonitrile in presence of iodine as a catalyst