Synthesis and biological evaluation of thymine nucleosides fused with 3′,4′-tetrahydrofuran ring

The pyrimidine nucleosides fused with 3′,4′-tetrahydrofuran ring were successfully synthesized, starting from 1,2;5,6-di-O-isopropylidene- -glucose and assayed for antiviral activities against HIV-1, HIV-2, EMCV, Cox. B3 and VSV. Thymine analogue (5) and its corresponding 2′-deoxy analogue (6) exhibited high cytotoxicity instead of giving antiviral activities.