Résumé
In the search for new chemotherapeutic agents, we have focused our work on the synthesis and the study of several unnatural β-
l-nucleoside analogues. In this paper, we report on the synthesis of β-
l-pentofuranonucleosides (and their 2′-deoxy derivatives) of 5-fluorouracil and their inhibitory effects on the proliferation of several murine and human tumor cells. The corresponding 5-fluorocytosine derivatives were also synthesized and their anti-HIV and anti-HBV activities have been evaluated.