Synthesis and Antisense Properties of 2′β-F-Arabinouridine Modified Oligonucleotides with 4′-C-OMe Substituent

A novel 2′-F,4′-C-OMe–arabinouridine (araU) was successfully synthesized and introduced into oligonucleotides. The oligonucleotide containing 2′-F,4′-C-OMe–araU exhibited improved nuclease resistance and RNA hybridizing selective ability relative to 2′-F–araU. In particular, when 2′-F,4′-C-OMe–araU inserted into C–H⋯F–C bonding-favorable 5′–uridine–purine–3′ steps, the modified oligonucleotide showed remarkable binding affinity and selectivity to RNA complements. Thus, 2′-F,4′-C-OMe–araU has valuable antisense properties and can be used as novel chemical modification for antisense therapeutic strategy.