C-Nucleosides To Be Revisited

Two new C-nucleoside analogues, BCX4430, an imino-C-nucleoside, and GS-6620, a phosphoramidate derivative of 1'-cyano-2'-C-methyl-4-aza-7,9-dideazaadenosine C-nucleoside, have been recently described as effective against filovirus infections (Marburg) and hepatitis C virus (HCV), respectively. The first C-nucleoside analogues were described about half a century ago. The C-nucleoside pseudouridine is a natural component of RNA, and various other C-nucleoside analogues have been reported previously for their antiviral and/or anticancer potential, the most prominent being pyrazofurin, tiazofurin, and selenazofurin. In the meantime, showdomycin, formycin, and various triazole, pyrazine, pyridine, dihydroxyphenyl, thienopyrimidine, pyrazolotriazine, and porphyrin C-nucleoside analogues have been described. It would be worth revisiting these C-nucleosides and derivatives thereof, including their phosphoramidates, for their therapeutic potential in the treatment of virus infections and, where appropriate, cancer as well.