The present invention provides, among other things, compounds represented by the general Formula I: and pharmaceutically acceptable salts thereof, wherein L and A (and further substituents) are as defined in classes and subclasses herein and compositions (e.g., pharmaceutical compositions) comprising such compounds, which compounds are useful as inhibitors of hepatitis C virus polymerase, and thus are useful, for example, as medicaments for the treatment of HCV infection.本發明尤其提供由通式I表示之化合物:及其醫藥學上可接受之鹽,其中L及A(及其他取代基)係如本文中之類別及子類中所定義;及包含該等化合物之組合物(例如醫藥組合物),該等化合物適用作C型肝炎病毒聚合酶之抑制劑,且因此適用作例如用於治療HCV感染之藥物。