SYNTHESIS OF 5-BIS(HYDROXYMETHYL)-1,3-DIOXOLAN-2-YL]NUCLEOSIDES AS POTENTIAL INHIBITORS OF HIV

The synthesis of 1,3-dioxolan-2-ylnucleosides and related chemistry is described. We have shown that 2-methoxy-1,3-dioxolane (6) reacts with silylated thymine and trimethylsilyl triflate to give the acyclic for mate ester 1-[2-(formyloxy)ethyl]thymine (8) rather than 1-(1,3-dioxol an-2-yl)thymine (7). A tentative mechanism which could explain this re sult is discussed. On the other hand, 2-methoxy-1,3-dioxolane 13c reac ts with silylated bases to give 5-bis(hydroxymethyl)-1,3-dioxolan2-yl] nucleosides, thus representing the first examples of this novel class of compounds. The nature of the nucleobase and the hydroxyl protecting groups was found to have great influence on the reaction and on the s tability of the nucleosides. Compounds 16 and 18 were found to be inac tive when tested for anti HIV-1 activity in vitro.