Synthesis and properties of oligonucleotides containing novel 2',4'-BNA analogues (2',4'-BNACOC).

Preorganization of the nucleoside into proper conformation is one of the most promising approaches to develop the oligonucleotides strongly interacting with nucleic acid targets in a sequence-specific manner. We designed and synthesized the 2',4'-BNACOC monomer as a novel bridged nucleic acid analogue possessing a fixed N-type sugar conformation, and also successfully achieved its incorporation into oligonucleotides. The 2',4'-BNACOC modified oligonucleotides were found to have selective and strong binding-affinity for complementary RNA rather than DNA, and to show an excellent nuclease resistance ability.