Eccles Natasha, Della Sala Flavio, Le Bailly Bryden A F, Whitehead George F S, Clayden Jonathan, Webb Simon J
Department of Chemistry University of Manchester Oxford Road Manchester M13 9PL UK.
Manchester Institute of Biotechnology University of Manchester 131 Princess St Manchester M1 7DN UK.
ChemistryOpen. 2020 Mar 18;9(3):338-345. doi: 10.1002/open.201900362. eCollection 2020 Mar.
Two α-aminoisobutyric acid (Aib) foldamers bearing Zn(II)-chelating N-termini have been synthesized and compared with a reported Aib foldamer that has a bis(quinolinyl)/mono(pyridyl) cap (BQPA group). Replacement of the quinolinyl arms of the BQPA-capped foldamer with pyridyl gave a BPPA-capped foldamer, then further replacement of the linking pyridyl with a 1,2,3-triazole gave a BPTA-capped foldamer. Their ability to relay chiral information from carboxylate bound to Zn(II) at the N-terminus to a glycinamide-based NMR reporter of conformational preference at the C-terminus was measured. The importance of the quinolinyl arms became readily apparent, as the foldamers with pyridyl arms were unable to report on the presence of chiral carboxylate in acetonitrile. Low solubility, X-ray crystallography and H NMR spectroscopy suggested that interfoldamer interactions inhibited carboxylate binding. However changing solvent to methanol revealed that the end-to-end relay of chiral information could be observed for the Zn(II) complex of the BPTA-capped foldamer at low temperature.
合成了两种带有锌（II）螯合N端的α-氨基异丁酸（Aib）折叠体，并将其与一种已报道的带有双（喹啉基）/单（吡啶基）帽（BQPA基团）的Aib折叠体进行比较。用吡啶基取代BQPA封端折叠体的喹啉基臂得到BPPA封端折叠体，然后用1,2,3-三唑进一步取代连接的吡啶基得到BPTA封端折叠体。测量了它们将N端与锌（II）结合的羧酸盐的手性信息传递到C端基于甘氨酰胺的构象偏好NMR报告基团的能力。喹啉基臂的重要性变得显而易见，因为带有吡啶基臂的折叠体无法报告乙腈中手性羧酸盐的存在。低溶解度、X射线晶体学和1H NMR光谱表明，折叠体间相互作用抑制了羧酸盐结合。然而，将溶剂改为甲醇后发现，在低温下，BPTA封端折叠体的锌（II）配合物可以观察到手性信息的端到端传递。
