Inhibition of Uridine Phosphorylase. Synthesis and Structure−Activity Relationships of Aryl-Substituted 1-((2-Hydroxyethoxy)methyl)-5-(3-phenoxybenzyl)uracil

Structure-activity relationship studies on a series of 1-((2-hydroxyethoxy)methyl)-5-(3-(substituted-phenoxy)benzyl)uracils as inhibitors of murine liver uridine phosphorylase have led to compounds with IC50s as low as 1.4 nM. The two most potent compounds, 10j (3-cyanophenoxy) and 11f (3-chlorophenoxy) were tested in vivo for effects on steady-state concentrations of circulating uridine in mice and rats. Both compounds were substantially more efficacious than BAU (5-benzylacyclouridine) both in vitro and in vivo.