The synthesis of the fully protected 16 possible natural  di-2′-deoxynucleoside phosphotriesters 6aa-dd  and 16 thiophosphotriesters 7aa-dd was achieved by  the phosphoramidite approach in solution in preparative scale.  The 5′-O-dimethoxytrityl-2′-deoxyribonucleoside  3′-[2-(p-nitrophenyl)ethyl] phosphoromorpholidites  3a-d and the 3′-O-benzyl-2′-deoxyribonucleosides  4a-d were used as starting materials.
                                    通过溶液中的
磷酸铵法,成功合成了16种完全保护的自然二-2′-脱氧核苷
磷酸三酯6aa-dd和16种
硫代磷酸三酯7aa-dd,达到制备规模。使用的起始材料是5′-O-二甲氧基三苯甲基-2′-脱氧核苷3′-[2-(对
硝基苯基)乙基]
磷酸吗啉酯3a-d和3′-O-苄基-2′-脱氧核苷4a-d。