Synthesis and properties of novel 2′-C,4′-C-ethyleneoxy-bridged 2′-deoxyribonucleic acids with exocyclic methylene groups

Three 2′-C,4′-C-ethyleneoxy-bridged 2′-deoxyribonucleic acids possessing six-membered bridges with 6′-oxygen and 8′-exocyclic methylene groups (methylene-EoDNAs) were designed and synthesized in nine to ten steps from 5-methyluridine. The methylene-EoDNA-modified oligonucleotides showed excellent binding affinity with target ssRNA and extremely high nuclease resistance compared with natural oligonucleotides. These results proved the potential of methylene-EoDNAs for nucleic acid based technology.