Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... Tethering the N 6 -substituents of N 6 -substituted adenosines to N1 has resulted in a series of conformationally restricted adenosine analogues. The resultant diimidazo[1,2-c:4′,5′-e] pyrimidines were shown to be adenosine A 1 selective. ... Tethering the N 6 -substituents ...