Epimeric methylsulfinyladenosine derivatives from the marine ascidian Herdmania momus

Investigation of the secondary metabolites of the ascidian Herdmania momus led to the isolation and characterization of four new nucleoside derivatives (1–4). Structural studies showed that these derivatives represent a series of rare methylsulfinyladenosine derivatives of interconvertible transesterification isomers and/or sulfinyl epimers. The antiviral activities of these rare nucleosides were evaluated against a series of human pathogenic viruses.