5-[2-deoxy-β-D-erythro-pentofuranosyl]-2-{[(dimethylamino)methylidene]amino}-3,5-dihydro-3-[(pivaloyloxy)methyl]-4H-pyrrolo[3,2-d]pyrimidin-4-one                                                                                                                                                              在
                                                                                                                                                                                 
吡啶   、                                                                                                  
N,N-二异丙基乙胺                                                                                                                                  作用下,
                                                                                                                以
                                                                                         
二氯甲烷                                                                                  为溶剂,
                                                                                                                                                    反应 5.5h,
                                                                                                                生成                                                 5-[2-deoxy-5-O-(4,4'-dimethoxytrityl)-β-D-erythro-pentofuranosyl]-2-{[(dimethylamino)methylidene]amino}-3-[(2,2-dimethyl-1-oxopropoxy)methyl]-3,5-dihydro-4H-pyrrolo[3,2-d]pyrimidin-4-one 3'-(2-cyanoethyl diisopropylphosphoramidite)