Synthesis and anti-HIV activities of symmetrical dicarboxylate esters of dinucleoside reverse transcriptase inhibitors

Three nucleoside analogues, 3'-fluoro-2',3'-dideoxythymidine (FLT), 3'-azido-2',3'-dideoxythymidine (AZT), and 2',3'-dideoxy-3'-thiacytidine (3TC) were conjugated with three different dicarboxylic acids to afford the long chain dicarboxylate esters of nucleosides. In general, dinucleoside ester conjugates of FLT and 3TC with long chain dicarboxylic acids exhibited higher anti-HIV activity than their parent nucleosides. Dodecanoate and tetradecanoate dinucleoside ester derivatives of FLT were found to be the most potent compounds with EC(50) values of 0.8-1.0 nM and 3-4 nM against HIV-1(US/92/727) and HIV-1(IIIB) cells, respectively. The anti-HIV activity of the 3TC conjugates containing long chain dicarboxylate diester (EC(50)=3-60 nM) was improved by 1.5-66 fold when compared to 3TC (EC(50)=90-200 nM). This study reveals that the symmetrical ester conjugation of dicarboxylic acids with a number of nucleosides results in conjugates with improved anti-HIV profile.