Syntéza nových heteroanelovaných 7-deazapurinových nukleosidů a nukleotidů s potenciální biologickou aktivitou a pro modifikace DNA a RNA

Fleuti, Marianne Heidi

Doctoral Thesis Abstract Marianne Fleuti Synthesis of novel hetero-fused 7-deazapurine nucleosides and nucleotides with potential biological activity or for modifications of DNA and RNA In medicinal chemistry, 7-deazapurine ribonucleosides are important analogues to purine nucleosides and represent a privileged scaffold in the research for new treatments against cancer, leukemia, and diseases caused by viruses. This thesis discusses the synthesis of new heteroaryl-fused 7-deazapurine ribonucleosides and reports on the biological activity of the target nucleosides against different cancer cell lines and viruses in vitro. In the first part of the thesis, the focus lies on the comparison of strategies for the synthesis of different methylpyrazolo-fused 7-deazapurine ribonucleosides. The tricyclic nucleobase was furnished by (i) a six-step classical heterocyclization approach starting from 5-chloro-1-methyl- 4-nitropyrazole, and by (ii) a three-step cross-coupling and cyclization approach starting from the zincated 4,6-dichloropyrimidine and 5-iodo-1-methylpyrazole. Both strategies resulted in comparable yields overall. Then, three different glycosylation methods were explored to give the β-anomeric nucleoside intermediate. Only the Vorbrüggen glycosylation yielded the intermediate as a pure β-anomer....

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