Adenosine, 5′-O-[bis(4-methoxyphenyl)phenylmethyl]-N-[[2-(4-nitrophenyl)ethoxy]carbonyl]-2′-O-[1-(phenylmethoxy)ethyl]-

Cytidine, 5′-O-[bis(4-methoxyphenyl)phenylmethyl]-N-[[2-(4-nitrophenyl)ethoxy]carbonyl]-2′-O-[1-(phenylmethoxy)ethyl]-

Guanosine, 5′-O-[bis(4-methoxyphenyl)phenylmethyl]-N-[[2-(4-nitrophenyl)ethoxy]carbonyl]-6-O-[2-(4-nitrophenyl)ethyl]-2′-O-[1-(phenylmethoxy)ethyl]-

Uridine, 5′-O-[bis(4-methoxyphenyl)phenylmethyl]-2′-O-[1-(phenylmethoxy)ethyl]-

Adenosine, N-[[2-(4-nitrophenyl)ethoxy]carbonyl]-2′-O-[1-[[4-[[[2-(4-nitrophenyl)ethoxy]carbonyl]oxy]phenyl]methoxy]ethyl]-

Cytidine, 2′-O-[1-[[3-fluoro-4-[[[2-(4-nitrophenyl)ethoxy]carbonyl]oxy]phenyl]methoxy]ethyl]-N-[[2-(4-nitrophenyl)ethoxy]carbonyl]-

Cytidine, N-[[2-(4-nitrophenyl)ethoxy]carbonyl]-2′-O-[1-[[4-[[[2-(4-nitrophenyl)ethoxy]carbonyl]oxy]phenyl]methoxy]ethyl]-

Guanosine, 2′-O-[1-[[3-fluoro-4-[[[2-(4-nitrophenyl)ethoxy]carbonyl]oxy]phenyl]methoxy]ethyl]-N-[[2-(4-nitrophenyl)ethoxy]carbonyl]-6-O-[2-(4-nitrophenyl)ethyl]-

Guanosine, N-[[2-(4-nitrophenyl)ethoxy]carbonyl]-2′-O-[1-[[4-[[[2-(4-nitrophenyl)ethoxy]carbonyl]oxy]phenyl]methoxy]ethyl]-6-O-[2-(4-nitrophenyl)ethyl]-

Adenosine, N-[[2-(4-nitrophenyl)ethoxy]carbonyl]-2′-O-[1-(phenylmethoxy)ethyl]-

Cytidine, N-[[2-(4-nitrophenyl)ethoxy]carbonyl]-2′-O-[1-(phenylmethoxy)ethyl]-

Guanosine, N-[[2-(4-nitrophenyl)ethoxy]carbonyl]-6-O-[2-(4-nitrophenyl)ethyl]-2′-O-[1-(phenylmethoxy)ethyl]-

Adenosine, 2′-O-[1-[[3-fluoro-4-[[[2-(4-nitrophenyl)ethoxy]carbonyl]oxy]phenyl]methoxy]ethyl]-N-[[2-(4-nitrophenyl)ethoxy]carbonyl]-3′,5′-O-[1,1,3,3-tetrakis(1-methylethyl)-1,3-disiloxanediyl]-

Adenosine, N-[[2-(4-nitrophenyl)ethoxy]carbonyl]-2′-O-[1-[[4-[[[2-(4-nitrophenyl)ethoxy]carbonyl]oxy]phenyl]methoxy]ethyl]-3′,5′-O-[1,1,3,3-tetrakis(1-methylethyl)-1,3-disiloxanediyl]-

Cytidine, 2′-O-[1-[[3-fluoro-4-[[[2-(4-nitrophenyl)ethoxy]carbonyl]oxy]phenyl]methoxy]ethyl]-N-[[2-(4-nitrophenyl)ethoxy]carbonyl]-3′,5′-O-[1,1,3,3-tetrakis(1-methylethyl)-1,3-disiloxanediyl]-

Cytidine, N-[[2-(4-nitrophenyl)ethoxy]carbonyl]-2′-O-[1-[[4-[[[2-(4-nitrophenyl)ethoxy]carbonyl]oxy]phenyl]methoxy]ethyl]-3′,5′-O-[1,1,3,3-tetrakis(1-methylethyl)-1,3-disiloxanediyl]-

Guanosine, 2′-O-[1-[[3-fluoro-4-[[[2-(4-nitrophenyl)ethoxy]carbonyl]oxy]phenyl]methoxy]ethyl]-N-[[2-(4-nitrophenyl)ethoxy]carbonyl]-6-O-[2-(4-nitrophenyl)ethyl]-3′,5′-O-[1,1,3,3-tetrakis(1-methylethyl)-1,3-disiloxanediyl]-

Guanosine, N-[[2-(4-nitrophenyl)ethoxy]carbonyl]-2′-O-[1-[[4-[[[2-(4-nitrophenyl)ethoxy]carbonyl]oxy]phenyl]methoxy]ethyl]-6-O-[2-(4-nitrophenyl)ethyl]-3′,5′-O-[1,1,3,3-tetrakis(1-methylethyl)-1,3-disiloxanediyl]-

Adenosine, N-[[2-(4-nitrophenyl)ethoxy]carbonyl]-2′-O-[1-(phenylmethoxy)ethyl]-3′,5′-O-[1,1,3,3-tetrakis(1-methylethyl)-1,3-disiloxanediyl]-

Cytidine, N-[[2-(4-nitrophenyl)ethoxy]carbonyl]-2′-O-[1-(phenylmethoxy)ethyl]-3′,5′-O-[1,1,3,3-tetrakis(1-methylethyl)-1,3-disiloxanediyl]-