Patent ID: 8785619

Claim:
A nucleoside of the following formula: wherein: R 1 is methyl; Y is monomethoxytrityl, dimethyoxytrityl, trimethoxytrityl, or tetrahydropyranyl; R′ is a phosphoramidite; Z is hydrogen, fluoro, or protected amino; said phosphoramidite is denoted by P—N(R 2 ,R 3 )(OCH 2 CH 2 CN) or P—N(R 2 ,R 3 )(OR 4 ), wherein R 2 and R 3 are selected from the group consisting of diisopropyl, diethyl, dimethyl, morpholino, and pyrrolidino; and R 4 is a lower alkyl containing 1-6 carbon atoms; and R 5 is phenoxy acetyl or 9-fluorenylmethoxycarbonyl.