Synthesis and antiviral evaluation of 1-deaza-8-aza- and 3-deaza-8-aza-purine nucleosides

8-Aza-purine nucleosides and their analogues have been throughly investigated as antimicrobial and antitumor agents. Less known are 1-deaza-8-aza- and 3-deaza-8-aza-purine derivatives. As a matter of fact, the synthesis of the 7-amino-3-beta-D-ribofuranosyl-v-triazolo[4,5-b]pyridine (1-deaza-8-aza-adenosine) and 4-amino-1-beta-D-ribofuranosyl-v-triazolo[4,5c]pyridine (3-deaza-8-aza-adenosine) has already been described. However, to the best of our knowledge, their biological properties have not been described. Here we report a new procedure for their synthesis, as well as the synthesis of the corresponding 2'-deoxy counterparts. 1-deaza-8-aza-adenosine and deoxy-adenosine (both as alfa and beta anomers) were tested in vitro for antiviral activity against a panel of DNA and RNA viruses, HIV included, but none of them resulted effective. The antiviral activity of 3-deaza-8-aza-adenosine and deoxy-adenosine will be reported.