[9-((2R,3R,4R,5R)-4-{12-[Dimethyl-(1,1,2-trimethyl-propyl)-silanyloxy]-dodecyloxy}-3-trityloxy-5-trityloxymethyl-tetrahydro-furan-2-yl)-9H-purin-6-yl]-trityl-amine

6-[(2R,3S,4R,5R)-5-(6-Amino-purin-9-yl)-4-hydroxy-2-hydroxymethyl-tetrahydro-furan-3-yloxy]-hexanoic acid 2-cyano-ethyl ester

6-[(2R,3S,4R,5R)-5-(6-Amino-purin-9-yl)-4-hydroxy-2-hydroxymethyl-tetrahydro-furan-3-yloxy]-hexanoic acid 9H-fluoren-9-ylmethyl ester

6-((2R,3S,4R,5R)-4-Hydroxy-2-hydroxymethyl-5-{6-[2-(4-nitro-phenyl)-ethoxycarbonylamino]-purin-9-yl}-tetrahydro-furan-3-yloxy)-hexanoic acid 9H-fluoren-9-ylmethyl ester

6-{(2R,3R,4R,5R)-2-Hydroxymethyl-5-{6-[2-(4-nitro-phenyl)-ethoxycarbonylamino]-purin-9-yl}-4-[2-(4-nitro-phenyl)-ethoxycarbonyloxy]-tetrahydro-furan-3-yloxy}-hexanoic acid 2-cyano-ethyl ester