Patent ID: 7148206

Claim:
A method for the treatment of a flavivirus or pestivirus infection in a host, comprising administering to said host an anti-virally effective amount of a compound of Formula XVII: or a pharmaceutically acceptable salt or ester thereof, wherein: Base is a purine; R 1 and R 2 are independently H; phosphate; a stabilized phosphate prodrug; acyl; alkyl; sulfonate ester; benzyl, wherein the phenyl group is optionally substituted with one or more substituents selected from hydroxyl, amino, alkylamino, arylamino, alkoxy, aryloxy, nitro, cyano, sulfonic acid, sulfate, phosphonic acid, phosphate, phosphonate, either unprotected or protected as necessary; 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 and R 2 are independently H or phosphate; R 6 is alkyl, azido, cyano, alkenyl, alkynyl, Br-vinyl, —C(O)O(alkyl), —O(acyl), —O(alkyl), —O(alkenyl), chloro, bromo, fluoro, iodo, NO 2 , NH 2 , —NH(lower alkyl), —NH(acyl), —N(lower alkyl) 2 , or —N(acyl) 2 ; R 7 and R 9 are independently OR 2 , hydroxy, alkyl, azido, cyano, alkenyl, alkynyl, Br-vinyl, —C(O)O(alkyl), —O(acyl), —O(alkyl), —O(alkenyl), chlorine, bromine, iodine, NO 2 , NH 2 , —NH(lower alkyl), —NH(acyl), —N(lower alkyl) 2 , or —N(acyl) 2 ; R 10 is H, alkyl, chlorine, bromine or iodine; X is O, S, SO 2 or CH 2 .