2-氰乙基N,N-二异丙基氯亚磷酰胺   、                                                                                      
7-bromo-5-[2-deoxy-5-O-(4,4'-dimethoxytrityl)-β-D-erythro-pentofuranosyl]-2-{[(dimethylamino)methylidene]amino}-3,5-dihydro-4H-pyrrolo[3,2-d]pyrimidin-4-one                                                                                                                                                              在
                                                                                                                                                                                 
N,N-二异丙基乙胺                                                                                                                                  作用下,
                                                                                                                以
                                                                                         
二氯甲烷                                                                                  为溶剂,
                                                                                                                                                    反应 0.5h,
                                                                                                                以78%的产率得到7-bromo-5-[2-deoxy-5-O-(4,4'-dimethoxytrityl)-β-D-erythro-pentofuranosyl]-2-{[(dimethylamino)methylidene]amino}-3,5-dihydro-4H-pyrrolo[3,2-d]pyrimidin-4-one 3'-(2-cyanoethyl diisopropylphosphoramidite)