Thiol derivatives of general formula (II) have antiviral activity, particularly against influenza virus. In particular, the compound (4-(2-chloro-4-nitrophenyl)piperazin-1-yl)(4-(2-fluoro-6-methoxyphenyl)-1-methyl-1H-1,2,3-triazol-5-yl)methanone is provided. Methods of preparing the compounds are also described.