Patent ID: 7772208

Claim:
A pharmaceutical composition for the treatment of an HCV infection in a host, comprising an effective treatment amount of a 2′,3′-dideoxynucleoside of the formula: or a pharmaceutically acceptable salt thereof, wherein (i) X is S═O, SO 2 , NR 1 , N + R 1 R 2 , CHF or CR 3 R 4 ; R 1 and R 2 are independently C 2-6 alkenyl, C 2-6 alkynyl, or C 3-8 cycloalkyl; R 3 and R 4 are independently hydrogen, halogen (F, Cl, Br, or I), OH or OR 5 , with the proviso that R 3 and R 4 are not both hydrogen; R 5 is hydrogen, an alkyl, an acyl, or a silyl; (ii) Y is NH 2 , NHR 6 , NR 6 R 7 , OH or OR 8 each R 6 , R 7 and R 7 is independently H, C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, C 3-8 cycloalkyl, cyclopropyl, or C 2-6 acyl; (iii) Z is chosen from hydrogen, halogen (F, Cl, Br, or I), C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, CN, CF 3 , N 3 , NO 2 , aryl, heteroaryl and COR 9 ; R 9 is chosen from H, OH, SH, C 1-6 alkyl, C 1-6 aminoalkyl, C 1-6 alkoxy and C 1-6 thioalkyl; and (iv) R is phosphate; acyl; —C(O)R 10 , alkyl; sulfonate ester; sulfonyl; a lipid; an amino acid; a carbohydrate; a peptide; a cholesterol; or other pharmaceutically acceptable leaving group; R 10 is a C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, aryl, monophosphate, diphosphate, triphosphate, or —P(O)(OR 11 ) 2 ; each R 11 is independently hydrogen, C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl or a hydroxyl-protecting group; together with pharmaceutically acceptable carrier.