Synthetic approaches towards nucleocidin and selected analogues; anti-HIV activity in 4′-fluorinated nucleoside derivatives

Nucleocidin 1 has been synthesised from the adenosine derivative 4via the intermediacy of the dihalogeno compound 9. The latter compound showed slight but significant activity against HIVinfected cells while the isomer 10 and the monohalogeno compound 60 were inactive. Synthetic approaches towards other 4′-fluorinated nucleoside derivatives are also described. The epimeric 4′fluorinated nucleosides 26 and 27 displayed similar activity against HIV-infected cells to that observed for the dihalogenated compound 9.