5′-O-DMTr-2′-O-TMBTM-G(iBu)-3′-CE-Phosphoramidite

N2-isobutyryl-5'-O-4, 4'-dimethoxytrityl)-2'-O-(2, 4, 6-trimethoxybenzylthiomethyl)- guanosine-3'-cyanoethyl Phosphoramidite