Synthesis, incorporation into triplex-forming oligonucleotide, and binding properties of a novel 2'-deoxy-C-nucleoside featuring a 6-(thiazolyl-5)benzimidazole nucleobase.

[reaction: see text] 6-(Thiazolyl-5)benzimidazole (B(t)()) was designed as a novel nucleobase for the specific recognition of an inverted A.T base pair in a triple helix motif. It was successfully incorporated into an 18-mer triplex-forming oligonucleotide (TFO) using the 2'-deoxy-C-nucleoside phosphoramidite 16. The triple helix binding properties of the modified TFO were examined by means of thermal denaturation experiments targeting an oligopyrimidine.oligopurine 26-mer DNA duplex containing an A.T base pair inversion.