Synthesis and antiviral activity of new carbonylphosphonate 2',3'-dideoxy-3'-thiacytidine conjugates

The synthesis of new potential PFA-BCH-189 conjugate analogues is described and their molecular structure clearly identified through NMR and mass spectra techniques. The anti-HIV-1 activity was determined according to the inhibition of syncytium formation in MT-4 cells, while the anti-HBV activity was determined in infected duck hepatocytes. Both antiviral activities of the PFA-BCH-189 conjugates were much lower than those of the parent BCH-189 (2',3'-dideoxy-3'-thiacytidine) (1). Whereas a prodrug effect, following cleavage and release of the free BCH-189 and PFA, cannot be ruled out, poor cellular permeation of the drug seems to be the most likely reason for the reduced activities against HIV and DHBV. The presence of the PFA moiety appears to be detrimental for both the anti-HIV and anti-DHBV activity of PFA-BCH-189 cases.