5'-O-dimethoxytritil-2'-O-methylcytidine-3'-O-(2-cianoethyl-N,N-diisopropylphosphoramidite) 以70%的产率得到4-amino-1-[(1S,6R,8R,9R,10R,15S,17R,18R)-17-(4-amino-2-oxopyrimidin-1-yl)-3,12-dihydroxy-9,18-dimethoxy-3,12-dioxo-2,4,7,11,16-pentaoxa-13-thia-3lambda5,12lambda5-diphosphatricyclo[13.3.0.06,10]octadecan-8-yl]pyrimidin-2-one