Patent ID: 7635689

Claim:
A method for the treatment of a Flaviviridae virus infection in a host, comprising administering to the host infected with a Flaviviridae virus an effective amount of a compound of formula or a pharmaceutically acceptable salt thereof, wherein: R 1 is hydrogen; phosphate; acyl; alkyl, sulfonate ester, a lipid, an amino acid; a carbohydrate; a peptide; a cholesterol; or other pharmaceutically acceptable leaving group which when administered in vivo provides a compound wherein R 1 is independently H or phosphate; R 2 is phosphate; acyl; alkyl, sulfonate ester, a lipid, an amino acid ester; a carbohydrate; a peptide; or a cholesterol; or other pharmaceutically acceptable leaving group which when administered in vivo provides a compound wherein R 2 is hydrogen; R 7 is halo; Base is selected from the group consisting of adenine, N 6 -alkylpurine, N 6 -acylpurine, N 6 -benzylpurine, N 6 -halopurine, N 6 -vinylpurine, N 6 -acetylenic purine, N 6 -acyl purine, N 6 -hydroxyalkyl purine, N 6 -alkylaminopurine, N 6 -thioalkyl purine, N 2 -alkylpurine, N 2 -alkyl-6-thiopurine, C 5 -hydroxyalkyl purine, N 2 -alkylpurine, N 2 -alkyl-6-thiopurine, guanine, hypoxanthine, 2,6-diaminopurine, and 6-chloropurine; and Y 3 is independently H, F, Cl, Br or I.