Abstract: Compounds represented by the formula: , and pharmaceutically acceptable salts thereof and prodrugs thereof; wherein R1 is H, CH3, C2H5, C3H7 R2 is H, CH3, C2H5, C3H7, CH?CH2, CH2—OH, CH2F, CF3 R?2 is H, OH, NH2, NH-alkyl, F, N3, OCH3, O—C(O)CH(NH2)alkyl R3 is H, CH3, C2H5, C3H7 R?3 is H, OH, NH2, NH-alkyl, F, N3, OCH3, O—C(O)CH(NH2)alkyl R4 is H, CH3, C2H5, C3H7 At least one of R2, R3, or R4 has to be other than H, when X?NH in B R6 is H, CH3, C2H5, R7 is selected from H, alkyl, alkenyl, aryl, acyloxyalkyl, and pivaloyloxyalkyl, aminoacids, CH2CH2SC(O)alkyl; and B is represented by the following structure: X is independently NR6, O, S, R8 and R9 independently is H, NH2, OH, SH, F, Cl, Br, I, aryl, heterocycle, alkyl, alkene, alkyne, S-alkyl, S-aryl, S(O)-alkyl, SO2-alkyl, SO2NH2, SO2NH-alkyl, SO2NH-aryl, NH-alkyl, NH-aryl, N(alkyl)2, N(aryl)2, O-alkyl, O-aryl, O-heterocycle, NH-(CH2)n-aryl, NH—C(O)-alkyl, NH—C(O)-aryl are useful for inhibiting viral RNA polymerases and treating patien

Abstract: The invention provides methods for treating hepatitis C viral infections and related viral infections, as well as compounds and compositions that are useful for treating such infections.

Abstract: The invention provides compounds of formula I, II, and III as described herein, as well as pharmaceutical compositions comprising the compounds, and synthetic methods and intermediates that are useful for preparing the compounds. The compounds of formula I, II, and III are useful as anti-viral agents and/or as anti-cancer agents.