Comparative Study of Carborane- and Phenyl-Modified Adenosine Derivatives as Ligands for the A2A and A3 Adenosine Receptors Based on a Rigid in Silico Docking and Radioligand Replacement Assay

Carboranes in drug discovery, chemical biology and molecular imaging

There exists a paucity of structural innovation and limited molecular diversity associated with molecular frameworks in drug discovery and biomolecular imaging/chemical probe design. The discovery and exploitation of new molecular entities for medical and biological applications will necessarily involve voyaging into previously unexplored regions of chemical space. Boron clusters, notably the carboranes, offer an alternative to conventional (poly)cyclic organic frameworks that may address some of the limitations associated with the use of novel molecular frameworks in chemical biology or medicine. The high thermal stability, unique 3D structure and aromaticity, kinetic inertness to metabolism and ability to engage in unusual types of intermolecular interactions, such as dihydrogen bonds, with biological receptors make carboranes exquisite frameworks in the design of probes for chemical biology, novel drug candidates and biomolecular imaging agents. This Review highlights the key developments of carborane derivatives made over the last decade as new design tools in medicinal chemistry and chemical biology, showcasing the versatility of this unique family of boron compounds.

Ruthenacarborane-Phenanthroline Derivatives as Potential Metallodrugs

Ruthenium-based complexes have received much interest as potential metallodrugs. In this work, four Ru^II complexes bearing a dicarbollide moiety, a carbonyl ligand, and a phenanthroline-based ligand were synthesized and characterized, including single crystal diffraction analysis of compounds 2, 4, and 5 and an observed side product SP1. Complexes 2-5 are air and moisture stable under ambient conditions. They show excellent solubility in organic solvents, but low solubility in water.

New keys for old locks: carborane-containing drugs as platforms for mechanism-based therapies

Icosahedral carboranes in medicine are still an emerging class of compounds with potential beneficial applications in drug design. These highly hydrophobic clusters are potential "new keys for old locks" which open up an exciting field of research for well-known, but challenging important therapeutic substrates, as demonstrated by the numerous examples discussed in this review.

Comparative study of inorganic, boron-rich cluster and organic, phenyl adenosine modifications: synthesis and properties

Background: Nucleoside analogs are important class of chemotherapeutics. One of the original openings in the nucleoside medicinal chemistry was derivatives comprising a boron cluster component. Results: A series of adenosine derivative pairs containing inorganic boron cluster or alternatively its mimic, organic phenyl modification were synthesized and their physicochemical and biological properties compared. Marked effects of boron clusters, which are qualitatively and quantitatively different from the phenyl group effects, were detected. The studied characteristics include syn/ anti conformation, lipophilicity, cytotoxicity and antiviral activity, as well as phosphorylation by adenosine kinase. Conclusion: The obtained results demonstrate usefulness of the boron clusters for tuning properties of biomolecules and prove their potential as modifying units in design of future therapeutics based on nucleoside structures.