Replacement of the phosphodiester linkage in oligonucleotides by heterocycles: the effect of triazole- and imidazole-modified backbones on DNA/RNA duplex stability

Thymidine dinucleotide analogs with imidazole-derived backbones (III and IV) were synthesized. These modified dimeric building blocks were incorporated into oligodeoxyribonucleotides. The hybridization affinity of the modified oligonucleotides for RNA complements was determined and compared to the corresponding olefinic modifications I and II.