CP3A Organic Synthesis Group and Services Communs, ICMMO, UMR 8182, CNRS, Université Paris Sud, Université Paris Saclay , Bât. 420, 15 rue Georges Clemenceau, 91405 Orsay cedex, France.
Inorganic and Organometallic Coordination Chemistry Laboratory and Laboratory for Medicinal Chemistry and Natural Products, Faculty of Sciences (I) & PRASE-EDST, Lebanese University , Hadath, Lebanon.
J Org Chem. 2017 May 5;82(9):4819-4828. doi: 10.1021/acs.joc.7b00494. Epub 2017 Apr 21.
A series of three short oligomers (di-, tri-, and tetramers) of cis-2-(aminomethyl)cyclobutane carboxylic acid, a γ-amino acid featuring a cyclobutane ring constraint, were prepared, and their conformational behavior was examined spectroscopically and by molecular modeling. In dilute solutions, these peptides showed a number of low-energy conformers, including ribbonlike structures pleated around a rarely observed series of intramolecular seven-membered hydrogen bonds. In more concentrated solutions, these interactions defer to an organized supramolecular assembly, leading to thermoreversible organogel formation notably for the tripeptide, which produced fibrillar xerogels. In the solid state, the dipeptide adopted a fully extended conformation featuring a one-dimensional network of intermolecularly H-bonded molecules stacked in an antiparallel sheet alignment. This work provides unique insight into the interplay between inter- and intramolecular H-bonded conformer topologies for the same peptide template.
一系列三个短寡聚物（二聚体、三聚体和四聚体）的顺式-2-（氨甲基）环丁烷羧酸，一种具有环丁烷环约束的 γ-氨基酸，被制备，并通过光谱和分子建模研究了它们的构象行为。在稀溶液中，这些肽显示了许多低能量构象，包括围绕罕见的一系列分子内七元氢键折叠的带状结构。在更浓的溶液中，这些相互作用让位于有组织的超分子组装，导致热可逆的有机凝胶形成，特别是对于三肽，它产生了纤维状的干凝胶。在固态中，二肽采用完全伸展的构象，具有分子间氢键的一维网络，分子堆积在反平行的片状排列中。这项工作提供了关于同一肽模板的分子内和分子间氢键构象拓扑之间相互作用的独特见解。
