{5:2'-O-[methyleneimino(2-oxoethane-2,1-diyl)]}-linked 5'-O-(4,4'-dimethoxytrityl)-P-thiouridyl-(3'->5')-2'-deoxy-3'-O-(tetrahdyro-2H-pyran-2-yl)uridine S-phenyl ester

5-(azidomethyl)-2'-deoxy-5'-O-pivaloyluridine

[(2R,3R,4R,5R)-5-[Bis-(4-methoxy-phenyl)-phenyl-methoxymethyl]-4-(tert-butyl-dimethyl-silanyloxy)-2-(2,4-dioxo-3,4-dihydro-2H-pyrimidin-1-yl)-tetrahydro-furan-3-yloxy]-acetic acid

5-(aminomethyl)-2'-deoxy-5'-O-pivaloyl-3'-O-(tetrahydro-2H-pyran-2-yl)uridine

2'-O-{2-{{{1-[2'-deoxy-5'-O-pivaloyl-3'-O-(tetrahydro-2H-pyran-2-yl)-β-D-ribofuranosyl]-1,2,3,4-tetrahydro-2,4-dioxopyrimidin-5-yl}methyl}amino}-2-oxoethyl}-5'-O-(4,4'-dimethoxytrityl)uridine

3'-O-[(tert-butyl)dimethylsilyl]-2'-O-{2-{{{1-[2'-deoxy-5'-O-pivaloyl-3'-O-(tetrahydro-2H-pyran-2-yl)-β-D-ribofuranosyl]-1,2,3,4-tetrahydro-2,4-dioxopyrimidin-5-yl}methyl}amino}-2-oxoethyl}-5'-O-(4,4'-dimethoxytrityl)uridine

2'-O-{2-{{{1-[2'-deoxy-5'-O-pivaloyl-3'-O-(tetrahydro-2H-pyran-2-yl)-β-D-ribofuranosyl]-1,2,3,4-tetrahydro-2,4-dioxopyrimidin-5-yl}methyl}amino}-2-oxoethyl}-5'-O-(4,4'-dimethoxytrityl)uridine 3'-(S,S'-diphenyl phosphorodithioate)