Ring-Constrained (N)-methanocarba nucleosides as adenosine receptor agonists: independent 5'-uronamide and 2'-deoxy modifications.

Novel methanocarba adenosine analogues, having the pseudo-ribose northern (N) conformation preferred at adenosine receptors (ARs), were synthesized and tested in binding assays. The 5'-uronamide modification preserved [N6-(3-iodobenzyl)] or enhanced (N6-methyl) affinity at A3ARs, while the 2'-deoxy modification reduced affinity and efficacy in a functional assay.