Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland.
Laboratory of Advanced Crystal Engineering, Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland.
Int J Mol Sci. 2023 Apr 6;24(7):6806. doi: 10.3390/ijms24076806.
Hybrids of short oligourea foldamers with residues of α, β and γ-amino acids esters at the C-terminus were obtained and subjected to a reaction with LiOH. There are two possible transformations under such conditions, one of which is ester hydrolysis and the formation of a carboxylic group and the other is the cyclization reaction after abstraction of a proton from urea by a base. We have investigated this reaction with difference C-terminal residue structures, as well as under different work-up conditions, especially for oligourea hybrids with α-amino acid esters. For these compounds, an oligourea-hydantoin combination is the product of cyclization. The stability of the hydantoin ring under alkaline conditions has been alsotested. Furthermore, this work reports data related to the structure of C-terminal-modified oligourea foldamers in solution and, for one compound, in the solid state. Helical folding is preserved both for cyclized and linear modifications, with oligourea-acid hybrids appearing to be more conformationally stable, as they are stabilized by an additional intramolecular hydrogen bond in comparison to cyclic derivatives.
将短寡缩氨酸折叠体与 C 末端的α、β和γ-氨基酸酯残基的混合物进行反应，用 LiOH 处理。在这种条件下有两种可能的转化，一种是酯水解，形成羧酸基团，另一种是在碱从脲中提取质子后发生环化反应。我们已经研究了具有不同 C 末端残基结构的这种反应，以及在不同的后处理条件下，特别是对于具有α-氨基酸酯的寡缩氨酸杂化物。对于这些化合物，环化的产物是寡缩氨酸-海因的组合。碱性条件下海因环的稳定性也进行了测试。此外，这项工作还报告了与溶液中 C 末端修饰的寡缩氨酸折叠体结构相关的数据，对于一种化合物，还报告了在固态中的结构数据。对于环化和线性修饰，螺旋折叠都得以保留，与环状衍生物相比，寡缩氨酸-酸杂化物具有更高的构象稳定性，因为它们通过额外的分子内氢键得到稳定。
