1. Introduction
Nucleosides possess a broad spectrum of biological functions
and they have a primary role as building blocks in the genetic code.
Numerous modified nucleoside derivatives, mainly with variations
of the sugar part and/or the heterocyclic base, have been developed
for screening as nontoxic selective inhibitors of kinases, transcriptase
reverses, polymerases, nucleoside phosphorylases and hydrolases
for the control of cancer, viral and antimicrobial diseases
[1].
In this regard, modifications in the carbohydrate moiety of nucleosides
and/or in the nucleic base have resulted in improved
biological properties [2] and, among these analogues, azanucleosides
have recently attracted a great deal of attention [2a,3