2,5'-Anhydrouridine

5'-O,2-Cyclouridine

2,5'-Epoxy-2,3-didehydro-2-deoxo-5'-deoxyuridine

(6R)-7,8,9,10-Tetrahydro-7α,8α-dihydroxy-6α,9α-epoxy-2H,6H-pyrimido[2,1-b][1,3]oxazocin-2-one