Preparation and properties of 2',5'-linked oligonucleotide analogues containing 3'-O,4'-C-methyleneribonucleosides.

Bicyclic nucleoside analogues, 3'-O,4'-C-methyleneuridine and -5-methyluridine, were successfully incorporated into oligonucleotides via connection with 2',5'-phosphodiester linkage, and hybridization behavior and nuclease stability of the modified oligonucleotides were investigated.