Like the very similar 2’-OMe backbone, the 2’-O-methoxyethyl-RNA (2’-MOE) backbone provides enhanced duplex stability, significant nuclease resistance and relatively low toxicity. As a result, 2’-MOE has been an attractive backbone for many therapeutic candidates, several of which have been approved by the FDA. These drugs have included 1) 2’-MOE/DNA chimeras to facilitate RNase H cleavage of target RNA sequences as well as 2) steric blocking oligonucleotides to alter the splicing of mRNA. The standard 2’-MOE nucleotides are A, 5-Me-C, G and 5-Me-U.
5'-O-(4,4'-Dimethoxytrityl)-2'-O-methoxyethyl-N6-benzoyl-adenosine -3'-O-[(2-cyanoethyl)-(N,N-diisopropyl)]-phosphoramidite
5'-O-(4,4'-Dimethoxytrityl)-2'-O-methoxyethyl-5-methyl-N4-benzoyl- cytidine-3'-O-[(2-cyanoethyl)-(N,N-diisopropyl)]-phosphoramidite
5'-O-(4,4'-Dimethoxytrityl)-2'-O-methoxyethyl-N2-isobutyryl- guanosine-3'-O-[(2-cyanoethyl)-(N,N-diisopropyl)]-phosphoramidite
5'-O-(4,4'-Dimethoxytrityl)-2'-O-methoxyethyl-5-methyl-uridine-3'-O-[(2-cyanoethyl)-(N,N-diisopropyl)]-phosphoramidite