1-[5-(4,4'-dimethoxytrityl)-2-O-methyl-4-thio-β-D-ribofuranosyl]-N-benzoyl-cytosine 、 2-cyanoethoxy-N,N,N',N'-tetraisopropylphosphoramidite 在
N,N-二异丙基乙胺 作用下,
以
二氯甲烷 为溶剂,
反应 2.0h,
以75%的产率得到3'-[(2-cyanoethyl)-N,N-diisopropylphosphoramidite]-5'-(4,4'-dimethoxytrityl)-2'-O-methyl-4'-thio-N-benzoyl-cytidine