Synthesis of 9-(2-Deoxy-2-fluoro-.BETA.-D-arabinofuranosyl)adenine Bearing a Selectively Removable Protecting Group.
作者:Tokumi MARUYAMA、Satoshi TAKAMATSU、Shigetada KOZAI、Yoshiko SATOH、Kunisuke IZAWA
DOI:10.1248/cpb.47.966
日期:——
A facile and practicam method to infroduce fluorine at the up-side of the 2'-carbon of nucleosides is described. 6-Chloropurine riboside 3 was converted to the 3'-O-benzoate 4a via a stannylene complex, then converted to the 3'-O-benzoyl-5'-O-tritylriboside 5a. In the presence of pyridine, migration of the 3'-benzoyl groups of 4a and 5a to 2'-OH was rather slow. Hence, 5a was reacted with diethylaminosulfur trifluoride (DAST) in CH2Cl2 in the presence of pyridine to give the 2'-deoxy-2'-fluoroarabinoside 6 in good yield. The 3'-O-benzoyl-5'-O-trityl protecting system was easy to deprotect selectively. Thus, treatment of 6 with ammonia in MeOH gave the 5'-O-trityl compound 7, which was subjected to esterificaiton with phenyl chlorothionoformate, radical deoxygenation with tris(trimethylsilyl)silane and acid treatment to afford 9-(2, 3-dideoxy-2-fluoro-β-D-threo-pento-furanosyl)adenine(FddA) 2. In addition, acid treatment of 7 gave 9-(2-deoxy-2-fluoro-β-D-arabinofuranosyl)adenine (FdaraA) 1.
本文介绍了一种在核苷 2'- 碳的上侧生成氟的简便实用的方法。6- 氯嘌呤核苷 3 通过斯坦尼烯络合物转化为 3'-O- 苯甲酸 4a,然后转化为 3'-O- 苯甲酰基-5'-O-三苯甲基核苷 5a。在吡啶存在的情况下,4a 和 5a 的 3'- 苯甲酰基向 2'-OH 的迁移相当缓慢。因此,在吡啶存在下,5a 在 CH2Cl2 中与二乙基三氟化硫(DAST)反应,得到 2'-deoxy-2'-fluoroarabinoside 6,收率很高。3'-O- 苯甲酰基-5'-O-三苯甲基保护体系很容易选择性地脱保 护。因此,用 MeOH 中的氨水处理 6,可得到 5'-O- 三苯甲基化合物 7,该化合物经氯硫代甲酸苯酯化、三(三甲基硅基)硅烷自由基脱氧和酸处理后,可得到 9-(2,3-二脱氧-2-氟-β-D-三戊基-呋喃糖基)腺嘌呤(FddA)2。此外,酸处理 7 得到 9-(2-脱氧-2-氟-β-D-阿拉伯呋喃糖基)腺嘌呤(FdaraA)1。