A variety of modified nucleosides or dinucleosides bearing one of the follo
wing functions have been prepared: N-hydroxyureas, N-hydroxyamines, N-hydro
xycarbamates, alpha-(N-hydroxyamino)phosphonates. Upon oxidation, these com
pounds afford the corresponding aminoxyl free radicals which have been stud
ied by EPR spectroscopy. Some of these compounds exhibited antiviral proper
ties.