Multicomponent Assembly of Diverse Pyrazin-2(1<i>H</i>)‑one Chemotypes

An expedient and concise Ugi-based approach for the rapid assembly of pyrazin-2­(1<i>H</i>)-one-based frameworks has been developed. This convergent approach encompasses skeletal, functional and stereochemical diversity, exhibiting an unusually high bond-forming efficiency as well as high structure and step economies. The method involves the use of readily available commercial reagents and is an example of the reconciliation of structural complexity with operational simplicity in a time- and cost-effective manner

Multicomponent Assembly of Diverse Pyrazin-2(1<i>H</i>)‑one Chemotypes

An expedient and concise Ugi-based approach for the rapid assembly of pyrazin-2­(1<i>H</i>)-one-based frameworks has been developed. This convergent approach encompasses skeletal, functional and stereochemical diversity, exhibiting an unusually high bond-forming efficiency as well as high structure and step economies. The method involves the use of readily available commercial reagents and is an example of the reconciliation of structural complexity with operational simplicity in a time- and cost-effective manner

Copper-Catalyzed Huisgen 1,3-Dipolar Cycloaddition under Oxidative Conditions: Polymer-Assisted Assembly of 4‑Acyl-1-Substituted-1,2,3-Triazoles

We herein document the first example of a reliable copper-catalyzed Huisgen 1,3-dipolar cycloaddition under oxidative conditions. The combined use of two polymer-supported reagents (polystyrene-1,5,7-triaza­bicyclo­[4,4,0]­dec-5-ene/Cu and polystyrene-2-iodoxy­benzamide) overcomes the thermodynamic instability of copper­(I) species toward oxidation, enabling the reliable Cu-catalyzed Huisgen 1,3-dipolar cycloadditions in the presence of an oxidant agent. This polymer-assisted pathway, not feasible under conventional homogeneous conditions, provides a direct assembly of 4-acyl-1-substituted-1,2,3-triazoles, contributing to expand the reliability and scope of Cu­(I)-catalyzed alkyne–azide cycloaddition

Discovery of 3,4-Dihydropyrimidin-2(1<i>H</i>)‑ones As a Novel Class of Potent and Selective A_2B Adenosine Receptor Antagonists

We describe the discovery and optimization of 3,4-dihydropyrimidin-2­(1<i>H</i>)-ones as a novel family of (nonxanthine) A_2B receptor antagonists that exhibit an unusually high selectivity profile. The Biginelli-based hit optimization process enabled a thoughtful exploration of the structure–activity and structure–selectivity relationships for this chemotype, enabling the identification of ligands that combine structural simplicity with excellent hA_2B AdoR affinity and remarkable selectivity profiles