Disclosed are compounds of Formula I, Formula II, and Fromula III. Also disclosed are salts of the compounds, pharmaceutical composition comprising the compounds or salts, and methods for treating HCV infection by administration of the compounds or salts.本發明揭示如化學式I、化學式II及化學式III之化合物。亦揭示該等化合物之鹽、含該等化合物或鹽之醫藥組合物,及投與該等化合物或鹽來治療HCV感染之方法。