3-[2-O-[(1,1-Dimethylethyl)dimethylsilyl]-3-O-(hydroxyphosphinyl)-β-D-ribofuranosyl]-3,4-dihydro-9H-imidazo[1,2-a]purin-9-one

3-[5-O-[Bis(4-methoxyphenyl)phenylmethyl]-2-O-[(1,1-dimethylethyl)dimethylsilyl]-β-D-ribofuranosyl]-3,4-dihydro-9H-imidazo[1,2-a]purin-9-one

3-[5-O-[Bis(4-methoxyphenyl)phenylmethyl]-2-O-[(1,1-dimethylethyl)dimethylsilyl]-3-O-(hydroxyphosphinyl)-β-D-ribofuranosyl]-3,4-dihydro-6-methyl-9H-imidazo[1,2-a]purin-9-one

3-[5-O-[Bis(4-methoxyphenyl)phenylmethyl]-3-O-[[bis(1-methylethyl)amino](2-cyanoethoxy)phosphino]-2-O-[(1,1-dimethylethyl)dimethylsilyl]-β-D-ribofuranosyl]-3,4-dihydro-6-methyl-9H-imidazo[1,2-a]purin-9-one

3-[5-O-[Bis(4-methoxyphenyl)phenylmethyl]-2-O-[(1,1-dimethylethyl)dimethylsilyl]-β-D-ribofuranosyl]-3,4-dihydro-6-methyl-9H-imidazo[1,2-a]purin-9-one