3',5'-O-[(tetraisopropyl)disiloxane-1,3-diyl]-N6-[2-(trifluoroacetylamino)ethylamino]-2'-deoxyadenosine

N6-{2-[1-(tert-butoxycarbonyl)imidazol-4-yl]ethyl}-5'-dimethoxytrityl-2'-deoxyadenosine

N6-{2-[1-(tert-butoxycarbonyl)imidazol-4-yl]ethyl}-2'-deoxyadenosine

N6-{2-[1-(tert-butoxycarbonyl)imidazol-4-yl]ethyl}-3',5'-O-[(tetraisopropyl)disiloxane-1,3-diyl]-2'-deoxyadenosine

5’-O-(4,4’-dimethoxytrityl)-N6-[2-(trifluoroacetylamino)ethyl]-2’-deoxyadenosine