The present invention provides fluorinated pyrrolo[2,3,d]pyrimidine
nucleoside compounds which are inhibitors of RNA-dependent RNA viral
polymerase. These compounds are inhibitors of RNA-dependent RNA viral
replication and are useful for the treatment of RNA-dependent RNA viral
infection. They are particularly useful as precursors to inhibitors of
hepatitis C virus (HCV) NS5B polymerase, as precursors to inhibitors of
HCV replication, and/or for the treatment of hepatitis C infection. The
invention also describes pharmaceutical compositions containing such
fluorinated pyrrolo[2,3-d]pyrimidine nucleoside alone or in combination
with other agents active against RNA-dependent RNA viral infection, in
particular HCV infection. Also disclosed are methods of inhibiting
RNA-dependent RNA polymerase, inhibiting RNA-dependent RNA viral
replication, and/or treating RNA-dependent RNA viral infection with the
fluorinated pyrrolo[2,3-d]pyrimidine nucleoside of the present invention.