2’-氧—甲基—核糖核苷的合成研究

【作者】 周芳；

【导师】 杜杨；

【作者基本信息】 南京理工大学 ， 应用化学， 2008， 硕士

【摘要】 2′-氧-甲基-核糖核苷,是通过对核苷进行甲基化修饰而得到的。这类2′-氧-甲基-核糖核苷广泛存在于RNA和DNA中,且成为用于第二代基因治疗的寡聚核苷酸序列合成的基本原料组分。含有这样核糖核酸的寡聚核苷酸在体内和体外都表现了较好的稳定性和较好地与目标互补基因的亲和能力。药理作用广泛,具有免疫调节、抗菌、抗炎、抗肿瘤等方面的作用。本文通过对2′-氧-甲基-核糖核苷的合成路线研究,综述并设计了可行的合成路线及方法。其中2′-氧-甲基-腺嘌呤核苷的合成是在无保护的情况下,直接使用重氮甲烷对腺嘌呤核苷甲基化,最终经过阴离子交换树脂分离得到纯的2′-氧-甲基-腺嘌呤核苷。而2′-氧-甲基-鸟嘌呤核苷的合成是以鸟嘌呤核苷为起始原料,经过五步反应合成出2′-氧-甲基-鸟嘌呤核苷。首先对鸟苷进行乙酰化反应,将鸟苷糖基上的3个羟基保护起来,得到2′,3′,5′-三-氧-乙酰基鸟苷;其次经氯化反应,使鸟苷上的6-位羟基被氯置换,得到化合物2-氨基-6-氯-2′,3′,5′-三-氧-乙酰基鸟苷;然后经NH₃气-MeOH的碱性条件处理,将乙酰基脱去,制得2-氨基-6-氯-鸟苷;之后再使用重氮甲烷对其进行甲基化,得到2-氨基-6-氯-2′-氧-甲基鸟苷,此步也会生成2-氨基-6-氯-3′-氧-甲基鸟苷,最后将2′和3′的异构体水解,使6位上的氯脱掉,最终经过阴离子交换树脂分离得到纯的2′-氧-甲基-鸟嘌呤核苷。通过熔点测试、红外、质谱、核磁等分析手段对合成的化合物的结构表征,结果表明所得的产物符合目标产物,所合成的化合物的结构、性能指标与设计目标要求一致。更多还原

【Abstract】 2′-O-Methylribonucleosides are modified by methylation of ribonucleosides. 2′-O-Methylribonucleosides are widely distributed in RNA and DNA, and now have been extensively utilized as a second-generation oligonucleotide constructs due to their favorable in-vitro and in-vivo properties. They provide a better stability and also strong binding capability to the complementary gene targets. They have many pharmacological functions such as immunoregulation, antibacterial, diminish inflammation and kill tumours.In this dissertation, the synthesis ways of 2′-O-Methylribonucleosides were studied and summarized, and practical and feasible ways were designed. The synthesis of 2′-O-methyl adenosine was directly accomplished by methylation of adenosine with diazomethane without protection, then the isomers were isolated through ion exchange chromatography on Dowex 1-X2(OH~-), getting pure 2′-O-methyl adenosine. The synthesis of 2′-O-methyl guanosine, starting from guanosine through five steps. Firstly, acetylation of guanosine, protecting three hydroxyl of guanosine. Secondly, 2-amino-6-chloro-9-β-D-ribofuranosyl-purine has been prepared via chlorination using phosphorus oxychloride or sulfur dioxide, and deacetylation of 2′,3′,5′-tri-O-acetyl guanosine. Moreover, high regioselective methylation of 2-amino-6-chloro-9-β-D-ribofuranosyl-purine with diazomethane, getting 2-amino-6-chloro-9-[2′-O-methyl-β-D-ribofuranosyl]-purine. Then followed by hydrolysis provided 2′-O-methyl guanosine and 3′-O-methyl guanosine. The isomers were isolated through ion exchange chromatography on Dowex 1-X2(OH~-), getting pure 2′-O-methyl guanosine.The structure of the synthetic products were characterized by Melting Point(MP), Infrared Spectoscopy(IR), Mass Spectra(MS) and ~1H Nuclear Magnetic Resonance(NMR). The results proved: the structures and performance indicated that the products conformed to the design requirement.更多还原