Abstract
A C-nucleoside with a stable C–C glycosidic bond can be used as a building block for
chemically modified oligonucleotides (ONs). In this study, two adenosine-like C-nucleosides
(dSA and dSO2A) bearing thieno[3,2-d]pyrimidine rings were designed and synthesized. These analogues were synthesized
via the Heck reaction, and their properties as monomer nucleosides were investigated.
Both the dSA and dSO2A monomers were not recognized by adenosine deaminase (ADA). In addition, they exhibited
fluorescence emissions in the UV and visible regions of dSA and dSO2A, respectively. Subsequently, dSA was converted into a phosphoramidite compound and incorporated into the ONs. The
synthesized dSA-modified ONs formed a stable duplex with DNA and RNA complements comparable to natural
adenosine. Furthermore, the modified ONs exhibited fluorescence emission derived from
dSA.
Key words
C-nucleoside - adenosine mimic - thienopyrimidine - oligonucleotide - fluorescence