Design and evaluation of a potential mutagen for Hepatitis C virus

Pyrrolopyrimidine nucleoside 1 was designed and synthesized as a potential mutagen for HCV. An in vitro HCV NS5B enzymatic assay indicated that pyrrolopyrimidine triphosphate acts as a CTP analog rather than a UTP analog. The SATE-prodrug of pyrrolopyrimidine monophosphate showed a weak inhibitory activity in an HCV replicon system (EC50 = 60 μM) and did not exhibit cytotoxicity (CC50 > 100 μM). Investigation of phosphorylation events using nucleoside kinases and LC–MS analysis revealed that the second phosphorylation step, from monophosphate ester to diphosphate ester, is unfavorable.