Xanthine-7-Ribosides as Adenosine A_l Receptor Antagonists: Further Evidence for Adenosine's Anti Mode of Binding

Abstract

The synthesis and A₁ adenosine receptor affinity of some xanthine-7-ribosides is described. It appears that these compounds are A, receptor antagonists. The orientation of the ribose moiety, as determined by ′H-NMR spectroscopy and theoretical chemical calculations, is compared with the orientation of the ribose in the agonist adenosine. Implications for the syn vs anti modes of binding to the receptor are discussed.