Synthesis using ring closure metathesis and effect on nucleoside transport of a (N)-methanocarba S-(4-nitrobenzyl)thioinosine derivative

[GRAPHICS] A new synthetic route to ring constrained (N) methanocarba nucleosides and nucleotides is presented. Ring closure of a diene intermediate using Grubbs catalyst provides a new avenue far the preparation of the cyclopentenone derivative 6, which is a versatile intermediate for various carbocycles. The product was almost as potent an inhibitor of es mediated nucleoside transport as the parent compound, inhibiting initial rates of uptake of uridine into cultured CCRF CEM cells by 50% at approximately 30-50 nM.