Download 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. ... 9-Vinylguanine, obtained for the first time and fully characterised by X-ray analysis, allows access to aza-analogues of 2′,3′-dideoxynucleosides through cycloaddition processes. ... The first preparation of N-9-vinylguanine allows access to aza-analogues of 2′,3′- ...