| abstract |
According to the present invention, there is provided a novel nucleoside derivative of the general formula (I), a pharmaceutically acceptable salt thereof, and a method for preparing the same, which are excellent in antiviral effect, in particular, anti-HBV (antihepatitis B virus) effect. .n n n n n n n n Wherein R 1 is hydrogen, phosphate, phosphonate, alkyl or acyl, R 2 is alkoxy or halogen, R 3 is a substituted or unsubstituted pyrimidine or purine base, X is O, S, SO or SO 2 to be.n n n Since the compound has two or more asymmetric carbon atoms, all possible stereoisomers and mixtures thereof are also included in the present invention. |