CHEMICAL SYNTHESIS OF A NEW MATERIAL OF ANTISENSE NUCLEIC ACID "2'-PHOSPHORYLATED RNAS" -DIRECTED TOWARD ITS BASIC STRUCTURAL STUDIES AND REGULATION OF EXPRESSION OF HIV VIRUS-

今年，我们试图研究合成2‘-磷酸化RNA所需的新的有机反应的发展。结果表明：首先，我们发现双(2-氰基-1，1-二甲基乙基)磷酰基不仅可以作为2‘-羟基的保护基，还可以作为2’-磷酸基团的前体。在二氯甲烷中用HF/Py去掉3‘，5-环硅基保护基团后，这种保护的磷酰基非常稳定，并且不会从3’-2‘羟基转移。这一发现使我们实现了关键中间体的构建，这是整个研究过程中所需的2‘-磷酸化3’-磷酰胺单元。该构筑单元用于固相合成2‘-磷酸化尿苷衍生物。我们可以高产率地合成2，4，6和10个2‘-磷酸化尿苷类化合物。它们被发现耐酸、碱条件以及脾磷酸二酯酶的酶消化。特别是，核磁共振证明10聚体具有独特的结构。目前，我们正在研究这些新的核酸衍生物与靶DNA或RNA片段的结合能力。

This year, we have tried to study the development of new organic reactions required for the synthesis of 2'-phosphorylated RNAs. As the result, we have achieved the following results : First, we found that bis (2-cyano-1,1-dimethylethyl) phosphoryl can be used not only as a 2'-hydroxyl protecting groups but also as a precursor of the 2'-phosphate group. This protected phosphoryl group was found to be quite stable upon removal of a 3', 5-cyclic silyl protecting group with HF/Py in dichloromethane and not to migrate from the 3'-2'hydroxyl functions. This finding led us to realize the construction of key intermediates, 2'-phosphorylated 3'-phosphoramide units which were required throughout this study. The building units were utilized for the solid phase synthesis of 2'-phosphorylated uridylate derivatives. We could synthesize 2,4,6, and 10mers of 2'-phosphorylated uridylates in good yields. They were found to be resistant to acid and alkaline conditions as well as enzymatic digestion with spleen phosphodiesterase. In particular, the 10 mer proved to have an unique structure as evidenced by NMR.At the present time, we are studying the binding ability of these new nucleic acid derivatives for target DNA or RNA fragmets.