Abstract: The present invention provides various novel oligonucleotide analogs having one or more properties that make the subject compounds superior to conventional oligonucleotides for use in procedures employing oligonucleotides. The compounds of the invention are oligonucleotide analogs in which the furanose ring of a naturally occurring nucleic acid is replaced with an amino acid or a modified amino alcohol residue. Some embodiments of the novel compounds of the invention are particularly useful for the antisense control of gene expression. The compounds of the invention may also be used as nucleic acid hybridization probes or as primers. Another aspect of the invention is to provide monomeric precursors of the oligonucleotide analogs of the invention. These monomeric precursors may be used to synthesize the subject polynucleotide analogs. Another aspect of the invention is to provide formulations of the subject polynucleotide analogs that are designed for the treatment or prevention of disease conditions.

Abstract: A number of modified nucleosides are disclosed composed of modified sugar moieties which contain substituents at C1 and C4 positions, or branched substituents at C3 and C5 positions of deoxyribose or ribose. Each nucleoside is converted to or properly protected and then converted to the corresponding phosphoramidites. These phosphoramidites are used to assemble oligonucleotides in which there is at least one forenoted nucleosides. These sugar modified oligonucleotides have the potential to be used as antisense therapies since they are expected to enhance nuclease resistance and cellular uptake while they maintain sequence-specificity and affinity to nucleic acid targets in vitro or in vivo.