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Synthesis and chemical properties of a novel 2',4'-bridged nucleic acid analogue with a seven-membered cyclic carbamate structure.

BNA We designed and synthesized a novel bridged nucleic acid (BNA) with N-type sugar conformation, possessing a seven-membered cyclic carbamate structure (2',4'-(CNC) monomer). The monomer shows interesting chemical properties, such as prompt migration of the carbamate bridge from the 2'-to the 3'-position and consequent conformational change of the furanose moiety. These chemical behaviors of 2',4'-BNA(CNC) were investigated by (1)H-NMR analysis, and the structure of the compound after migration was confirmed by X-ray crystallographic analysis.