The present invention provides compositions methods for treating susceptible viral infections, especially hepatitis C viral (HCV) infections as well as co infections of HCV with other viruses such as HBV and/or HIV. In one embodiment, the present invention provides compositions having the formula (I) and their use in treating viral infections:or a pharmaceutically acceptable salt, ester, stereoisomer, tautomers, solvate, prodrug, or combination thereof.
