Studies On The Synthesis Of C-8-Modified Photosensitive Purine Nucleosides

C-8 modified purine derivatives play prominent roles in biology, biochemistry and pharmaceutical areas. Moreover, if we modify purine nucleosides at C-8 with some groups with certain activities, oligonucleotides with special properties can be obtained through solid-phase phosphoramidite method.On the basis of the literature at home and abroad, we learned that, 3',5'-O-diacetyl-(E)-8-styryl-guanosine is self-assembly by light. In this paper, we have devoted our efforts to modify 2'-deoxyguanosine at C-8 with photosensitive group ((E)-styryl) to get the desired DNA monomer. (E)-8-styryl-2'-deoxyguanosine was obtained via Suzuki-Miyaura coupling reaction, using 8-bromo-2'-deoxyguanosine, (E)-2-phenylvinylboronic acid and triphenylphosphine-3,3',3"-trisulfonic acid trisodium salt (TPPTS) as raw material. Then we modified the deoxyguanosine derivative according to solid-phase phosphoramidite method, which should protect N2 position on the base, as well as protect the hydroxyl groups on the deoxyribose with certain bases, and got the DNA monomer. Currently, tests of its various properties are in progress.As alkali metals and alkali metals could be dissolved in organic solvents by the help of crown ethers, crown ethers have a wide range of applications in organic synthesis, optical resolution, heavy metal chelation, separation, analysis, physiological activity of medicine, biochemistry and so on. Coumarin and its derivatives are lactone compounds widely distributed in nature. It has been widely used in medicine, light-emitting materials, organic photosensitive dyes, fluorescent probes, and many other fields with its anti-tumor and other pharmacological activities and fluorescence properties. So we designed and synthesized the C-8 modified purine nucleoside, hoping to introduce azacrown ether and coumarin into adenosine, which with biological activities and fluorescence properties. Unexpectedly, we got the corresponding glycosidic bond disconnected compounds. We proceeded with its fluorescence characteristics detection. In addition, a series of C-8-modified purine nucleoside analogues were synthesized by different procedures. The reaction conditions of some products were optimized, which made the synthesis more simplely and efficiently.Additionally, a series of pyrimidine peptide nucleic acid monomers-base acetic acid were synthesized. Easier synthesis and good isolated yields were achieved under microwave irradiation in neat water.Their structures were confirmed by 1HNMR, 13CNMR, 31PNMR, IR and HRMS.What we reported opens an effective new avenue for the synthesis of C-8-purine photosensitive adducts, and enriched the types of nucleosides. The results have good value and academic application.