αβα-Tripeptide that contains a cyclic β-amino acid with an eight-membered ring, a cis-2-aminocyclooct-5-enecarboxylic acid (cis-ACOE) or a cis-2-aminocyclooctanecarboxylic acid (cis-ACOC) displayed an 11/9-helical turn in the crystal state. The related α/β-peptide oligomers were shown to adopt 11/9-helical conformations in solution.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1039/c4ob00266k | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Enantioselective Synthesis of Nonfused Eight-Membered O-Heterocycles by Sequential Catalysis.
Org Lett
January 2025
Catalytic Hydrogenation Research Center, State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Key Laboratory of Green Pesticides and Cleaner Production Technology of Zhejiang Province, Zhejiang University of Technology, Hangzhou 310014, P. R. China.
This work describes a chiral bifunctional squaramide/DBU sequential catalytic strategy for the enantioselective synthesis of nonfused chiral eight-membered O-heterocycles through the asymmetric addition of ynones to β,γ-unsaturated α-ketoesters followed by the regio- and diastereoselective cyclization of the adduct intermediates. Mechanistic experiments revealed that an isomerization process should be involved in the ring formation step, and the origin of the high regioselectivity and diastereoselectivity has also been elucidated by the DFT calculations.
View Article and Find Full Text PDFSecondary-ion-promoted active site redistribution in molecular sieves: A strategy to enhance catalyst bifunctionality.
J Colloid Interface Sci
December 2024
Key Laboratory of Groundwater Resources and Environment (Jilin University), Ministry of Education, College of New Energy and Environment, Jilin University, Changchun 130021, China. Electronic address:
As the frontier of environmental catalysis, mercury removal by deNO unit over bifunctional catalyst has emerged. However, it is fundamentally challenging to achieve simultaneous NO and mercury removal in industrial flue gas due to the commercial selective catalytic reduction (SCR) molecular sieves' lack of demercuration active centers. Herein, we demonstrate an active site in situ reconfiguration approach to enhance the oxidation of elemental mercury and immobilize divalent mercury by modified commercial SCR catalysts.
View Article and Find Full Text PDFSynthesis of Azocine-Fused Indoles via Gold(I)-Catalyzed Cyclization of Azido-alkynes.
J Org Chem
January 2025
Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
Herein, we report a gold(I)-catalyzed cascade cyclization of azido-alkynes bearing an enol ester moiety, leading to indole-fused eight-membered rings. This method allows for the one-step construction of indole and tetrahydroazocin-4-one via an α-imino gold carbene intermediate. The resulting scaffold would be useful for accessing natural products with an eight-membered ring-fused indole moiety.
View Article and Find Full Text PDFModulation of the Magnetic Anisotropy via the Ligand Field in Sandwiched Erbium Complexes.
Inorg Chem
December 2024
Institute of Nano Science and Technology, Sector-81, Mohali, Punjab 140306, India.
Among lanthanide-based single-molecule magnets (SMMs), erbium(III) is a Kramers ion, apart from dysprosium(III), which provides magnetic bistability in the presence of a suitable coordination environment. However, Er-based SMMs exhibit significantly less magnetic anisotropy than Dy because their prolate electronic density necessitates equatorially correlated ligands to minimize the charge contact with the Er atom. Here, in this work, we have computationally investigated the heteroleptic organometallic complexes with an Er(III) atom sandwiched between two distinct cyclic rings (five- and eight-membered) with the aim of tuning the magnetic anisotropy via exploiting the ligand field.
View Article and Find Full Text PDFRing Size Effects on the Structures of Sandwich Compounds with a Stoichiometry of CHM (M = Ti-Ni).
Organometallics
December 2024
Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602, United States.
Ring size effects on geometries and electronic structures were investigated for the (C H )M(C H ) ( = 4, 5, or 6; = 8, 7, or 6; + = 12; M = Ti-Ni) systems using density functional theory. The lowest-energy CHM structures for the early transition metals titanium, vanadium, and chromium are the experimentally known singlet (η-CH)Ti(η-CH), doublet (η-CH)V(η-CH), and singlet (η-CH)Cr, respectively. The likewise experimentally known singlet (η-CH)Ti, doublet (η-CH)V, and singlet (η-CH)Cr(η-CH) are the second-lowest-energy structures with only a small energy difference between the two vanadium structures.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!