Patent ID: 7534767

Claim:
A compound of the structural formula I: or a pharmaceutically acceptable salt thereof; wherein X is O, S, or NR 8 ; Y is CR 11 or N; R 1 is selected from the group consisting of hydrogen, fluoro, azido, amino, hydroxy, C 1-3 alkoxy, mercapto, and C 1-3 alkylthio; R 2 and R 3 are each independently selected from the group consisting of hydrogen, methyl, C 1-16 alkylcarbonyl, C 2-18 alkenylcarbonyl, C 1-10 alkyloxycarbonyl, C 3-6 cycloalkylcarbonyl, C 3-6 cycloalkyloxycarbonyl, CH 2 O(C═O)C 1-4 alkyl, CH(C 1-4 alkyl)O(C═O)C 1-4 alkyl, or an amino acyl residue of structural formula R 4 is hydrogen, azido, methyl, hydroxymethyl, or fluoromethyl; R 5 is hydrogen, C 1-10 alkylcarbonyl, phosphoryl or a cyclic prodrug ester thereof, diphosphoryl, triphosphoryl, C 2-18 alkenylcarbonyl, C 1-10 alkyloxycarbonyl, C 3-6 cycloalkylcarbonyl, C 3-6 cycloalkyloxycarbonyl, CH 2 O(C═O)C 1-4 alkyl, CH(C 1-4 alkyl)O(C═O)C 1-4 alkyl, or an amino acyl residue of structural formula R 6 and R 7 are each independently hydrogen, hydroxy, halogen, C 1-4 alkoxy, amino, C 1-4 alkylamino, di(C 1-4 alkyl)amino, C 3-6 cycloalkylamino, di(C 3-6 cycloalkyl)amino, benzylamino, dibenzylamino, or C 4-6 heterocycloalkyl, wherein alkyl, cycloalkyl, benzyl, and heterocycloalkyl are unsubstituted or substituted with one to five groups independently selected from halogen, hydroxy, amino, C 1-4 alkyl, and C 1-4 alkoxy; R 8 is hydrogen or C 1-4 alkyl; R 9 is hydrogen, C 1-5 alkyl, or phenyl C 0-2 alkyl; R 10 is hydrogen, C 1-4 alkyl, C 1-4 acyl, benzoyl, C 1-4 alkyloxycarbonyl, phenyl C 0-2 alkyloxycarbonyl, C 1-4 alkylaminocarbonyl, phenyl C 0-2 alkylaminocarbonyl, C 1-4 alkylsulfonyl, or phenyl C 0-2 alkylsulfonyl; and R 11 is hydrogen, methyl, halogen, azido, or amino; and provided that when Y is CH and X is NH and R 1 =R 2 =R 3 =R 4 =R 5 =hydrogen, then R 6 is not OH.