R-1479 (4′-Azidocytidine), a nucleoside analogue, is a specific inhibitor of RNA-dependent RNA polymerase (RdRp) of HCV. R-1479 inhibits HCV replication in the HCV subgenomic replicon system (IC50=1.28 μM). R-1479 is a click chemistry reagent, it contains an Azide group and can undergo copper-catalyzed azide-alkyne cycloaddition reaction (CuAAc) with molecules containing Alkyne groups. It can also undergo strain-promoted alkyne-azide cycloaddition (SPAAC) reactions with molecules containing DBCO or BCN groups.