8-Substituted Analogues of 3-(3-Cyclopentyloxy-4-methoxy-benzyl)-8-isopropyl- adenine: Highly Potent and Selective PDE4 Inhibitors

Crystal structures of N6-modified-amino acid nucleobase analogs(iii): adenine–valeric acid, adenine–hexanoic acid and adenine–gabapentine

H-bonding networks, anion–π and π–π interactions in the crystal structures of N⁶-modified-amino acid adenine analogs are investigated by means of DFT calculations and X-ray crystallography analysis.

Crystal structures of N6-modified-amino acid related nucleobase analogs (II): hybrid adenine-β-alanine and adenine-GABA molecules

H-Bonding networks and anion–π interactions in the crystal structures of N⁶-modified-amino acid adenine analogs are investigated using X-ray crystallography and DFT calculations.

The future of the oral pharmacotherapy of male erectile dysfunction: things to come

The convincing clinical data on the use of the orally active phosphodiesterase inhibitors sildenafil, vardenafil and tadalafil for the treatment of male erectile dysfunction have boosted research activities on the physiology of the male erectile mechanism. This included both peripheral intracellular signal transduction in the corpus cavernosum as well as central brain and spinal cord pathways controlling penile erection. This work provided the basis for the development and introduction of several new therapeutic modalities into the management of erectile dysfunction, some of which are already offered to the patients. As the concept of 'taking a pill' as a cure for an illness or the relief of symptoms of a disease has become widely accepted by the consumers, the pharmacologic treatment of erectile dysfunction has primarily focussed on selective, orally available drugs acting by influencing intracellular or central regulatory mechanisms, combining a high response rate and the advantage of an on-demand intake. These agents are regarded as more efficacious, and have a faster onset of drug action in the target tissue and an improved effect to side-effect ratio. The purpose of this review is to describe the major novel and evolving pharmacologic advances in the field of oral pharmacotherapy for the treatment of male erectile dysfunction.

The purines: potent and versatile small molecule inhibitors and modulators of key biological targets

The goal of this review is to highlight the wide range of biological activities displayed by purines, with particular emphasis on new purine-based agents which find potential application as chemical-biology tools and/or therapeutic agents. The expanding interest in the biological properties of polyfunctionalized purine derivatives issues, in large part, from the development of rapid high-throughput screening essays for new protein targets, and the corresponding development of efficient synthetic methodology adapted to the construction of highly diverse purine libraries. Purine-based compounds have found new applications as inducers of interferon and lineage-committed cell dedifferentiation, agonists and antagonists of adenosine receptors, ligands of corticotropin-releasing hormone receptors, and as inhibitors of HSP90, Src kinase, p38alpha MAP kinase, sulfotransferases, phosphodiesterases, and Cdks. The scope of application of purines in biology is most certainly far from being exhausted. Testing purine derivatives against the multitude of biological targets for which small molecule probes have not yet been found should thus be a natural reflex.

Solid-phase synthesis of 7-substituted 3H-imidazo[2,1-i]purines

A method for solid-supported synthesis of N,N-disubstituted (3H-imidazo[2,1-i]purin-7-yl)methyl amines has been developed. The key features of this library synthesis are: (i) immobilization of commercially available N6-benzoyl-5'-O-(4,4'-dimethoxytrityl)-2'-deoxyadenosine 3'-(2-cyanoethyl N,N-diisopropylphosphoramidite) by phosphitylation to a hydroxyl-functionalized support, (ii) quantitative conversion of the deprotected adenine base to 3H-imidazo[2,1-i]purine-7-carbaldehyde with bromomalonaldehyde in DMF in the presence of formic acid and 2,6-lutidine, (iii) reductive amination of the formyl group followed by N-alkylation or N-acylation, and (iv) release from the support by acidolytic cleavage of the N-glycosidic bond. Steps (ii) and (iii) have been optimized in some detail by using (adenin-9-yl)acetic acid anchored to a Phe-Wang resin as a model compound.