Structure-activity relationship for some 2',3'-dideoxynucleoside anti-HIV drugs using molecular electrostatic potential mapping

Molecular electrostatic potential(MEP) maps of azido thymidine (AZT), some of its analogs and derivatives and certain other 2',3'-dideoxy nucleosides having different anti-HIV activities have been studied. The optimised hybridization displacement charges (I-IDC) combined with MNDO Lowdin charges, continuosly distributed in three dimension spherically symmetrically as a Slater cloud at each site were used to compute the MEP maps. The negative MEP region near the O5' sites of these molecules appears to be of primary importance from the point of view of their anti-HIV activity. The roles of the azido group in AZT and fluorine atoms substituted at different positions in the sugar moiety have been evaluated. The azido group in AZT behaves as a strongly electronegative group.