5'-O-(4,4'-dimethoxytrityl)-6-O-(4-nitrophenylethyl)-2-N-(4,9,13-triazatridecane-1-yl)-2'-deoxyguanosine

5'-O-(4,4'-Dimethoxytrityl)-6-O-[2-(4-nitrophenyl)ethyl]-2-[tris-N,N',N''-trifluoroacetamido-(3,9,13-triazatridecyl])-2'-deoxyguanosine

O6-benzyl-3',5'-bis-O-(tert-butyldimethylsilyl)-2'-deoxyxanthosine

O6-benzyl-3',5'-bis-O-(tert-butyldimethylsilyl)-O2-(4-methylphenylsulfonyl)-2'-deoxyxanthosine

2-phenyl-O6-benzyl-3',5'-bis-O-(tert-butyldimethylsilyl)-2'-deoxyinosine