β-2′-C-Methyl purines (1, 2) are known inhibitors of hepatitis C virus (HCV). We herein report the synthesis, biological and enzymatic evaluation of their 5′-phosphoramidate ProTides. Described herein are seven l-alanine phosphoramidate derivatives with variations to the amino acid ester. The 1-naphthyl phosphoramidate of β-2′-methylguanosine containing the benzyl ester (20) was the most active at 0.12 μM, an 84-fold of increase in ...