Synthesis of 2′-O-alkylcarbamoylethyl-modified oligonucleotides with enhanced nuclease resistance that form isostable duplexes with complementary RNA

To expand the variety of 2'-O-modified oligonucleotides, we synthesized 2'-O-carbamoylethyl-modified oligonucleotides bearing ethyl, n-propyl, n-butyl, n-pentyl, and n-octyl groups on their nitrogen atoms. The corresponding nucleosides were synthesized using 2'-O-benzyloxycarbonylethylthymidine, which was easily converted into the carboxylic acid through hydrogeneration; subsequent condensation with the appropriate amine gave the desired nucleoside. We evaluated the effect of the 2'-O-alkylcarbamoylethyl modifications on duplex stability by analyzing melting temperature, which revealed the formation of isostable duplexes. In addition, we also revealed that these modifications, especially octylcarbamoylethyl, endowed these oligonucleotides with resistance toward a 3'-exonuclease. These results highlight the usefulness of the 2'-O-alkylcar-bamoylethyl modification for various biological applications.

Automated summary

A variety of 2'-O-alkylcarbamoyl-ethyl modified oligonucleotides were synthesized, showing improved duplex stability and resistance to 3'-exonuclease. These modifications have been proven useful for various biological applications.