Synthesis and Structural Studies of Novel Carbopeptoids and Their Triazole Analogs
Vitālijs Rjabovs

13.12.2013. 14:00, Materiālzinātnes un lietišķās ķīmijas fakultātē, Āzenes ielā 14/24, 272. telpā

Māris Turks

Grigorijs Veinbergs, Aigars Jirgensons, Jeroen Codee

The doctoral thesis discusses the synthesis and the use of novel carbohydrate-based molecular scaffolds for the syntheses of carbopeptoids and their triazole mimetics. Two approaches for the synthesis of modified oligosaccharides are demonstrated: one of them uses sequential addition of monosaccharides to the growing oligomeric chain in a “1+1+1…” fashion; the other is based on a sequential addition of disaccharides to the growing oligomeric chain in a “2+2+2…” fashion. The latter method allows the synthesis of both all-triazole-linked and amide-triazole-linked carbopeptoids. The synthesized oligosaccharides were studied by NMR and CD methods. The distances between the protons in the molecules were calculated from their NMR spectra and were used as the restraints in the molecular dynamics simulations. The obtained results suggest that the conformation distribution is not affected by the chain length of the all-triazole-linked oligosaccharides. Minor influence of the solvent is observed for these structures. The results of MD studies revealed that the all-triazole-linked oligosaccharides can form β-turn-type structures. Due to the flexibility of the molecules of the amide-triazole-linked carbopeptoids their conformations and secondary structures cannot be determined unambiguously by spectroscopic methods and/or the MD simulations. No intramolecular hydrogen bonds are observed between the amide protons and amide carbonyl groups. However, weak hydrogen bonds between the amide protons and oxygen atoms of the carbohydrate rings can be presumed in these structures. Comparison of the NMR and CD spectra of amide-triazole-linked octasaccharides reveals that the flexibility of the molecule decreases in different solvents. It can be rationalized that less populated conformations are stabilized by the solvent molecules. The results of MD suggest that the unstabilized β-turn-type structures can be formed by the amide-triazole-linked oligosaccharides. The developed synthetic routes towards the sugar amino acid precursors after minor last step modifications provided entries into a broad range of carbohydrate-azole conjugates. The latter group of products can be interesting in terms of medicinal chemistry.


Rjabovs, Vitālijs. Synthesis and Structural Studies of Novel Carbopeptoids and Their Triazole Analogs. PhD Thesis. Rīga: [RTU], 2013. 225 p.

Publication language
English (en)
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