Replacement of the phosphodiester linkage in oligonucleotides by an amide: Effect of backbone length on duplex stability with RNA complement

Five dimers containing amide linkages instead of the natural phosphodiester linkage were synthesized and incorporated into oligonucleotides. The length of the amide backbone was varied. The hybridization properties of the modified oligonucleotides with RNA complements and their conformational analysis are described and compared to previously reported amide containing oligonucleotides. In addition, the synthesis of a thioamide phosphoramidite dimer is reported.