DEVELOPMENT OF NOVEL SPIN-LABELED NUCLEOSIDES

我们设计了一种新型的带有n-叔丁基氨基氧基的自旋标记核苷，该基直接引入核碱基。合成了含氨基氧基的嘌呤和嘧啶核苷，研究了n -叔丁基氨基氧基在核碱基上的稳定性和行为。1)测定了6- n -叔丁基氨基氧基尿苷（1a）和6- n -叔丁基氨基氧基胞苷（2a）的EPR光谱。与2a本身的aN值（13 gauss）相比，在鸟苷衍生物（12.7 gauss）的存在下，2a的aN值降低了10倍。2)为了研究含有2′-脱氧6- n -叔丁基氨基尿苷(4)的寡核苷酸的EPR光谱，将自由基前体3掺入到15-mer中。不幸的是，与天然型15-mer相比，含有3的15-mer的Tm值明显降低，并且没有对含有寡核苷酸的4进行EPR研究。3)我们计划合成2'-脱氧5- n -叔羟胺尿苷(5)和2- n -叔羟胺肌苷(6)，它们可能具有反构象，并且它们掺入寡核苷酸中不会破坏稳定的双相结构。通过2'-脱氧5-碘吡啶钠盐的金属卤素交换反应，成功合成了5。我们也合成了6。

We designed a new type of spin-labeled nucleosides with an N-tert-butyl aminoxyl raical which is introduced to nucleobase directly. Purine and pyrimidine nucleosides with aminoxyl radical were synthesized to investigate stability and behavior of N-tert-butyl aminoxyl radical on nucleobase.1) EPR spectra of 6-N-tert-butyl aminoxyl uridine (1a) and 6-N-tert-butyl aminoxyl cytidine (2a) were measured. The aN value of 2a decreased in the presence of 10 equiv. of guanosine derivatives (12.7 gauss) compared to that of 2a itself (13 gauss).2) In order to study EPR spectra of oligonucleotide containing 2'-deoxy 6-N-tert-butyl aminoxyl uridine (4), 3, the precursor of radical, was incorporated into 15-mer. Unfortunately, the Tm value of 15-mer containing 3 decreased considerably compared to natural type 15-mer and EPR studies of 4 containing oligonucleotide were not done.3) We planned to synthesis of 2'-deoxy 5-N-tert-hydroxylamino uridine (5) and 2-N-tert-hydroxylamino inosine (6), which might have anti conformation and their incorporation into oligonucleotide might not disturb stable duplex formation. We successfully synthesized 5 via metal halogen exchange reaction of 2'-deoxy 5-iodouridine sodium salts. We also synthesized 6.