In this research,phosphate and thiophosphate prodrugs 3a,3b of anti-HIV agent AZT were synthesized,and their anti-HIV activities and cytotoxicities were investigated in vitro.Results showed that the prodrugs 3a and 3b with an IC50 value of 11.0 and 4.0 μmol-L-1,respectively,were less toxic than AZT(1.0 μmol-L-1).Although the EC50 values of both 3a(0.04 μmol-L-1) and 3b(0.16 μmol-L-1) were lower than that of AZT(0.01 μmol-L-1),the therapeutic index(IC50/EC50) of prodrug 3a(275) was much higher than that of both AZT(100) and prodrug 3b(25).This indicated that the prodrug 3a merited further investigation as an anti-HIV agent.
