Synthesis and anti-HCV activity of a series of β-d-2′-deoxy-2′-dibromo nucleosides and their corresponding phosphoramidate prodrugs

Abstract Several β- d -2′-deoxy-2′-substituted nucleoside analogs have displayed potent and selective anti-HCV activities and some of them have reached human clinical trials. In that regard, we report herein the synthesis of a series of 2′-deoxy,2′-dibromo substituted U, C, G and A nucleosides 10a–d and their corresponding phosphoramidate prodrugs 13a–d . The synthesized nucleosides 10a–d and prodrugs 13a–d were evaluated for their inhibitory activity against HCV as well as cellular toxicity. The results showed that the most potent compound was prodrug 13a , which exhibited micromolar inhibitory activity (EC 50  = 1.5 ± 0.8 µM) with no observed toxicity. In addition, molecular modeling and free energy perturbation calculations for the 5′-triphosphate formed from 13a and related 2′-modified nucleotides are discussed.