Novel bitriazolyl nucleosides were synthesized via the Huisgen reaction, starting with 3-azidotriazole nucleoside (1). Surprisingly, its isomer, 5-azidotriazole nucleoside (1′) did not yield the corresponding Huisgen reaction products efficiently because it was rapidly reduced to amine in the presence of Cu(II)–ascorbate. The significant differences between the reactivity of these two isomers in Cu(II)–ascorbate mediated reactions are mainly due to differences in their electronic properties and steric congestion as a result of different relative positions of the azido and the ribosyl moieties.
order to study the mechanisms responsible for their antiviraleffects using a photolabeling approach, we have developed photolabelingprobes of ribavirin and EICAR, in which an azido group was introduced into the pseudobases of triazole and imidazole, respectively. The ribavirin photoprobes were obtained by directly coupling the azidotriazole to the protected ribose sugar, while the EICAR probe was prepared