The present invention relates to an improved method of preparing adefovir dipivoxil of Formula 1. The method of the present invention is characterized by using dimethylsulfoxide as a reaction solvent, and comprises a process of preparing adefovir dipivoxil of Formula 1 by allowing adefovir of Formula 2 to react with chloromethylpivalate at a reaction temperature of 30 to 50℃ under the presence of dimethylsulfoxide and triethylamine solvents.一種製備式1之肝適能的改良方法。本發明之方法的特色是利用二甲亞碸作為反應溶劑。本發明之方法包括製備式1之肝適能的過程,其藉由在反應溫度為30℃到50℃且存在二甲亞碸溶劑與三乙胺溶劑的環境下,使式2的阿德福韋與三級戊酸氯甲基酯反應。
