Synthesis, duplex-forming ability, enzymatic stability, and in vitro antisense potency of oligonucleotides including 2ʹ-C,4ʹ-C-ethyleneoxy-bridged thymidine derivatives
We synthesized thymidine derivatives of 2ʹ-C,4ʹ-C-ethyleneoxy-bridged 2ʹ-deoxyribonucleic acids with 8ʹ-methyl group ((R)-Me-EoDNA and (S)-Me-EoDNA) and without any substituent (EoDNA). Oligonucleotides including these EoDNAs showed high hybridization abilities with complementary RNA and excellent enzymatic stabilities compared with natural DNA. Moreover, in vitro antisense potency of oligonucleotides with these EoDNAs and our recently reported methylene-EoDNAs was investigated and compared with that of LNA, which is a practical chemical modification for oligonucleotide-therapeutic agents. The results showed that EoDNAs and methylene-EoDNAs could be promising candidates for antisense technology.