Disaccharide nucleosides with 2'-O-(D-arabinofuranosyl), 2'-O-(L-arabinofuranosyl), 2'-O-(D-ribopyranosyl), 2'-O-(D-erythrofuranosyl), and 2'-O-(5-azido-5-deoxy-D-ribofuranosyl) substituents were synthesized. These modified nucleosides were incorporated into oligonucleotides (see Table). Single substitution resulted in a DeltaT(m) of +0.5 to -1.4 degrees for DNA/RNA and a DeltaT(m) of - 0.8 to -4.7 degrees for DNA/DNA duplexes. These disaccharide nucleosides can be well accommodated in RNA/DNA duplexes, and the presence of a NH2- C(5") group has a beneficial effect on duplex stability.
Disaccharide nucleosides with 2'-O-(D-arabinofuranosyl), 2'-O-(L-arabinofuranosyl), 2'-O-(D-ribopyranosyl), 2'-O-(D-erythrofuranosyl), and 2'-O-(5-azido-5-deoxy-D-ribofuranosyl) substituents were synthesized. These modified nucleosides were incorporated into oligonucleotides (see Table). Single substitution resulted in a DeltaT(m) of +0.5 to -1.4 degrees for DNA/RNA and a DeltaT(m) of - 0.8 to -4.7 degrees for DNA/DNA duplexes. These disaccharide nucleosides can be well accommodated in RNA/DNA duplexes, and the presence of a NH2- C(5") group has a beneficial effect on duplex stability.