Patent ID: 7547704

Claim:
A compound of Formula (VI): or a pharmaceutically acceptable salt thereof, wherein: R 1 is H; phosphate; acyl; an amino acid ester; a carbohydrate; a peptide; or pharmaceutically acceptable leaving group which when administered in vivo provides a compound wherein R 1 is H or phosphate; R 2 is acyl; an amino acid ester; a carbohydrate; a peptide; or a pharmaceutically acceptable leaving group which when administered in vivo provides a compound wherein R 2 is H Base is selected from the group consisting of each R 4 and R 5 is independently hydrogen, acyl, alkyl, lower alkyl, alkenyl, alkynyl or cycloalkyl; X is CH 2 , CHF, CF 2 , C(Y 3 ) 2 , CHCN, C(CN) 2 , CHR 4 or C(R 4 ) 2 ; X 2 is H, straight chained, branched or cyclic alkyl, CH 3 , CF 3 , or fluoro; X 3 is H or CH 3 ; Y 3 is H, F, Cl, Br or I; R 6 is alkyl, CF 3 , alkenyl, or alkynyl; R 7 is OH, O(acyl), or halo; R 8 and R 11 are hydrogen; R 9 is OH or OR 2 ; R 10 is hydrogen; and wherein each alkyl is optionally substituted with one or more substituents selected from the group consisting of fluoro, chloro, bromo, iodo, hydroxyl, amino, alkylamino, arylamino, alkoxy, aryloxy, nitro, cyano, sulfonic acid, sulfate, phosphonic acid, phosphate, and phosphonate.