Constrained analogues of 2′-nor cyclic nucleoside monophosphates

The synthesis of constrained analogues of 2′-nor-cyclic nucleosides monophosphates containing a thiomethylene tether was readily accomplished from the oxathiolane intermediate 4. The uracil, cytosine, and 5-bromocytosine spirophosphate analogues 22, 16, and 25 were inhibitory to HCMV replication in Flow 2002 cells.