Patent ID: 8227431

Claim:
A compound of the formula (IA): wherein, B a is Nitrogen heterocycle of from C3 to C15, selected from the group consisting of optionally substituted purine selected from adenine or guanine, pyrimidine selected from cytosine, uracil, or thymine, pteridine, triazolopyridine, imidazolopyridine, imidazolotriazine, pyrrolopyrimidine, or pyrazolopyrimidine; Nitrogen heterocycle may be bound to the sugar moiety in the nucleoside through any available ring Nitrogen atom; R 2 a and R 3 a independently are selected from OH, methyl, CH 3 C(O)O, CH 3 CH(CH 3 )C(O)O, CH 3 CH2CH2CH2C(O)O, PhC(O)O, or NH 2 CH(R a )C(O)O, wherein R a is H, alkyl, or benezyl; R 1 a is OH, CH 3 C(O)O, PhC(O)O, CH 3 CH 2 CH 2 C(O)O, CH 3 CH(CH 3 )C(O)O, CH 3 CH 2 CH 2 CH 2 C(O)O or NH 2 CH(R a )C(O)O, wherein R a is H, alkyl, or benezyl; a pharmaceutically acceptable salt thereof, a pharmaceutically acceptable solvate thereof, a pharmaceutically acceptable hydrate thereof, an N-oxide thereof, a tautomer thereof, a regioisomer thereof, a stereoisomer thereof, a prodrug thereof or a polymorph thereof.