Synthesis of 2'-deoxy-2'-fluoro-4'-thioarabinonucleosides using the Pummerer rearrangement and their biological evaluation.

Searching for more effective antineoplastic and antiviral agents, we have prepared various 2'-deoxy-2'-fluoro-4'-thioarabinonucleosides. The glycosylation reaction of persilylated pyrimidine bases with a 4-thiosugar derivative was performed using SnCl4 as a catalyst. The same reaction between purines and the 4-thiosugar, catalyzed by TMSOTf, gave the corresponding purine 4'-thionucleosides. Pyrimidine derivatives (e.g., 5-ethyluracil, 5-iodouracil, and 5-iodocytosine) showed potent anti-HSV-1 activities, and guanine and 2,6-diaminopurine derivatives showed marked anti-HCMV activities.