Synthesis and properties of a novel bridged nucleic acid with a P3 to N5 phsophoramidate linkkage, 5'-amino-2',4'-BNA
5A-Amino-2A,4A-BNA, a novel analogue of BNA series compounds, was successfully synthesized, and its incorporated oligonucleotides showed potent duplex- and triplex-forming ability and resistance against snake venom phosphodiesterase.