The synthesis and biological evaluation of novel bridging nucleoside analogues.

Novel bridging nucleoside analogues were prepared by cycloaddition reactions between pyranose glycals and barbiturate-derived, reactive thionoimides in modest yields. In all of the reactions conducted, the major cycloadducts obtained were the bottom faced adducts resulting from endo addition to the glycal. The adducts were stable to a variety of acidic reaction conditions and several of the compounds showed moderate activities against HIV-1 in primary human lymphocytes. One compound displayed anti-herpes simplex virus type-1 activity in Vero cells. Cytotoxicity measurements were also obtained.