Synthesis of (±)-1,2,3-triazolo-3′-deoxy-4′-hydroxymethyl carbanucleosides via ‘click’ cycloaddition

The synthesis of 1,2,3-triazolo-3′-deoxy-4′-hydroxymethyl carbanucleosides with different reaction conditions and diverse modulations on the heterocycle residues was developed. Heterocycle moieties were efficiently introduced on the pseudo-sugar either via nucleophilic substitution or via 1,3-dipolar Huisgen cycloaddition. With this latter approach, 1,4-disubstituted and 1,4,5-trisubstituted-(±)-[1,2,3]-triazolo-3′-deoxy-4′-hydroxymethyl carbanucleosides were prepared from the corresponding azido-carbocycle and various terminal or internal alkynes. Antiviral activities and cellular toxicities of the final compounds were evaluated as smallpox inhibitors. Unfortunately, at concentrations up to 100 mM, none of them inhibited production of vaccinia virus (Lister strain) or cowpox virus (Brighton strain) in vero cells.