A method of treating hepatitis C virus (HCV) infection comprising administering to a mammal in need of such treatment a therapeutically effective amount of a compound of structural formula III, or a pharmaceutically acceptable salt or acyl derivatives thereof, wherein B is W is O or S; Y is H, C₁-10 alkylcarbonyl, P₃O₉H₄, P₂O₆H₃, or P(O)R⁹R¹⁰; R¹ is CF₃, or C_1-4 alkyl and one of R² and R³ is OH or C_1-4 alkoxy and the other of R² and R³ is fluoro; R⁶ is H, OH, SH, NH₂, C_1-4 alkylamino, di(C_1-4 alkyl)amino, C_3-6 cycloalkylamino, halogen, C_1-4 alkyl, C_1-4 alkoxy, or CF₃; R⁵ is H, C_1-6 alkyl, C_2-6 alkenyl, C_2-6 alkynyl, C_1-4 alkylamino, CF₃, or halogen; and R⁹ and R¹⁰ are each independently hydroxy, OCH₂CH₂SC(═O)t-butyl, or OCH₂O(C═O)iPr. view more

The method of claim 1 wherein a compound of structural formula III, or a pharmaceutically acceptable salt or acyl derivatives thereof is in combination with a therapeutic amount of another agent active against HCV infection selected from the group consisting of ribavirin; levovirin; thymosin apha-1; an inhibitor of NS3 serine protease; an inhibitor of inosine monophosphate dehydrogenase; and interferon-α or pegylated interferon-α. view more

A compound having the formula: <chemistry id="CHEM-US-00183" num="00183"><img id="EMI-C00183" he="27.86mm" wi="69.85mm" file="US08481712-20130709-C00183.TIF" alt="embedded image" img-content="chem" img-format="tif"/></chemistry> or a pharmaceutically 24.38mm" wi="17.44mm" file="US08481712-20130709-C00184.TIF" alt="embedded image" img-content="chem" img-format="tif"/> L is CH or N; E is N or CR⁵; W is O or S; R¹ is C_2-4 alkenyl, C_2-4 alkynyl, or C_1-4 alkyl optionally substituted with amino, hydroxy, or 1 to 3 fluorine atoms; R³ is hydroxy or C_1-4 alkoxy; and R² is selected from the group consisting of halogen, C_1-4 alkyl, optionally substituted with 1 to 3 fluorine atoms, C_1-10 alkoxy, optionally substituted with C_1-3 alkoxy or 1 to 3 fluorine atoms, C_2-6 alkenyloxy, C_1-4 alkylthio, C_1-8 alkylcarbonyloxy, aryloxycarbonyl, azido, amino, C_1-4 alkylamino, and di(C_1-4 alkyl)amino; R⁴ and R⁶ are each independently H, OH, SH, NH₂, C_1-4 alkylamino, di(C_1-4 alkyl)amino, C_3-6 cycloalkylamino, halogen, C_1-4 alkyl, C_1-4 alkoxy, or CF₃; R⁵ is H, C_1-6 alkyl, C_2-6 alkenyl, C_2-6 alkynyl, C_1-4 alkylamino, CF₃, or halogen; R¹² and R¹³ are each independently hydrogen or methyl. view more

A compound having the formula: <chemistry id="CHEM-US-00185" num="00185"><img id="EMI-C00185" he="27.86mm" wi="69.85mm" file="US08481712-20130709-C00185.TIF" alt="embedded image" img-content="chem" img-format="tif"/></chemistry> or a pharmaceutically 24.47mm" wi="17.44mm" file="US08481712-20130709-C00186.TIF" alt="embedded image" img-content="chem" img-format="tif"/> L is CH or N; E is N or CR⁵; W is O or S; R¹ is C_2-4 alkenyl, C_2-4 alkynyl, or C_1-4 alkyl optionally substituted with amino, hydroxy, or 1 to 3 fluorine atoms; R³ is hydroxy or C_1-4 alkoxy; and R² is selected from the group consisting of halogen, C_1-4 alkyl, optionally substituted with 1 to 3 fluorine atoms, C_1-10 alkoxy, optionally substituted with C_1-3 alkoxy or 1 to 3 fluorine atoms, C_2-6 alkenyloxy, C_1-4 alkylthio, C_1-8 alkylcarbonyloxy, aryloxycarbonyl, azido, amino, C_1-4 alkylamino, and di(C_1-4 alkyl)amino; R⁴ and R⁶ are each independently H, OH, SH, NH₂, C_1-4 alkylamino, di(C_1-4 alkyl)amino, C_3-6 cycloalkylamino, halogen, C_1-4 alkyl, C_1-4 alkoxy, or CF₃; R⁵ is H, C_1-6 alkyl, C_2-6 alkenyl, C_2-6 alkynyl, C_1-4 alkylamino, CF₃, or halogen; and R¹² and R¹³ are each independently hydrogen or methyl. view more

A compound having the formula: <chemistry id="CHEM-US-00187" num="00187"><img id="EMI-C00187" he="27.86mm" wi="69.85mm" file="US08481712-20130709-C00187.TIF" alt="embedded image" img-content="chem" img-format="tif"/></chemistry> or a pharmaceutically e="24.47mm" wi="17.44mm" file="US08481712-20130709-C00188.TIF" alt="embedded image" img-content="chem" img-format="tif"/> L is CH or N; E is N or CR⁵; W is O or S; R¹ is C_2-4 alkenyl, C_2-4 alkynyl, or C_1-4 alkyl optionally substituted with amino, hydroxy, or 1 to 3 fluorine atoms; R³ is hydroxy or C_1-4 alkoxy; and R² is selected from the group consisting of halogen, C_1-4 alkyl, optionally substituted with 1 to 3 fluorine atoms, C_1-10 alkoxy, optionally substituted with C_1-3 alkoxy or 1 to 3 fluorine atoms, C_2-6 alkenyloxy, C_1-4 alkylthio, C_1-8 alkylcarbonyloxy, aryloxycarbonyl, azido, amino, C_1-4 alkylamino, and di(C_1-4 alkyl)amino; R⁴ and R⁶ are each independently H, OH, SH, NH₂, C_1-4 alkylamino, di(C_1-4 alkyl)amino, C_3-6 cycloalkylamino, halogen, C_1-4 alkyl, C_1-4 alkoxy, or CF₃; R⁵ is H, C_1-6 alkyl, C_2-6 alkenyl, C_2-6 alkynyl, C_1-4 alkylamino, CF₃, or halogen; and R¹² and R¹³ are each independently hydrogen or methyl. view more

The compound of claim 1, wherein B is: <chemistry id="CHEM-US-00190" num="00190"><img id="EMI-C00190" he="23.96mm" wi="17.10mm" file="US08481712-20130709-C00190.TIF" alt="embedded image" img-content="chem" img-format="tif"/></chemistry>

The compound of claim 2, wherein B is: <chemistry id="CHEM-US-00192" num="00192"><img id="EMI-C00192" he="23.96mm" wi="17.10mm" file="US08481712-20130709-C00192.TIF" alt="embedded image" img-content="chem" img-format="tif"/></chemistry>

A compound having the formula: <chemistry id="CHEM-US-00194" num="00194"><img id="EMI-C00194" he="19.05mm" wi="69.85mm" file="US08481712-20130709-C00194.TIF" alt="embedded image" img-content="chem" img-format="tif"/></chemistry> or a pharmaceutically 3.96mm" wi="17.27mm" file="US08481712-20130709-C00195.TIF" alt="embedded image" img-content="chem" img-format="tif"/> Y is P₃O₉H₄ or P₂O₆H₃; R¹ is C_1-4 alkyl; R² is fluoro; R³ is OH or C_1-4 alkoxy. view more

The compound of claim 9, or a pharmaceutically acceptable salt thereof, wherein Y is P<sub>3</sub>O<sub>9</sub>H<sub>4</sub>.

The compound of claim 9, or a pharmaceutically acceptable salt thereof, wherein Y is P<sub>2</sub>O<sub>6</sub>H<sub>3</sub>.