Two pairs of atropisomeric bisindole alkaloids, gelsekoumidines A (1) and B (2), with a new carbon skeleton, were isolated from the roots of Gelsemium elegans. Compounds 1 and 2 represent the first examples of seco-koumine-gelsedine type alkaloids, which feature an unprecedented 20,21-seco-koumine scaffold fused with a gelsedine framework via a double bond. Their structures including absolute stereochemistry were elucidated by spectroscopic data, single-crystal X-ray diffraction, and electronic circular dichroism (ECD) calculation. A plausible biogenetic pathway for the new compounds is also proposed. Compound 2 exhibited a moderate inhibitory effect against nitric oxide (NO) production.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/acs.orglett.7b02463 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
CySP3-96 enables scalable, streamlined, and low-cost sample preparation for cysteine chemoproteomic applications.
Mol Cell Proteomics
December 2024
Biological Chemistry Department, David Geffen School of Medicine, UCLA, Los Angeles, CA, 90095, USA; Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA, 90095, USA; Molecular Biology Institute, UCLA, Los Angeles, CA, 90095, USA; DOE Institute for Genomics and Proteomics, UCLA, Los Angeles, CA, 90095, USA; Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, CA, 90095, USA; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, UCLA, Los Angeles, CA, 90095, USA. Electronic address:
Cysteine chemoproteomic screening platforms are widely utilized for chemical probe and drug discovery campaigns. Chemoproteomic compound screens, which use a mass spectrometry-based proteomic readout, can interrogate the structure activity relationship (SAR) for thousands of proteins in parallel across the proteome. The versatility of chemoproteomic screens has been demonstrated across electrophilic, nucleophilic, and reversible classes of molecules.
View Article and Find Full Text PDFThe Triceptide Maturase OscB Catalyzes Uniform Cyclophane Topology and Accepts Diverse Gly-Rich Precursor Peptides.
ACS Chem Biol
June 2024
Department of Pharmacy and Pharmaceutical Sciences, National University of Singapore, 4 Science Dr 2, Singapore 117544.
Triceptides are a class of ribosomally synthesized and post-translationally modified peptides defined by an aromatic C(sp) to Cβ(sp) bond. The Gly-rich repeat family of triceptide maturases (TIGR04261) are paired with precursor peptides (TIGR04260) containing a Gly-rich core peptide. These maturases are prevalent in cyanobacteria and catalyze cyclophane formation on multiple Ω1-X2-X3 motifs (Ω1 = Trp and Phe) of the Gly-rich precursor peptide.
View Article and Find Full Text PDFDiaryl-Pyrano-Chromenes Atropisomers: Stereodynamics and Conformational Studies.
Molecules
June 2023
Department of Industrial Chemistry "Toso Montanari", University of Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy.
The dynamic scenario of di-aryls-pyrano-chromenes was investigated using DFT calculations. The symmetry of the chromene scaffold and the presence of two -substituted aryls substituents can generate two / diastereoisomers and conformational enantiomers with different rotational barriers. The relative conformations and configurations were derived using NOESY-1D experiments.
View Article and Find Full Text PDFAtroposelective Silylation of 1,1'-Biaryl-2,6-diols by a Chiral Counteranion Directed Desymmetrization Enhanced by a Subsequent Kinetic Resolution.
Angew Chem Int Ed Engl
July 2023
Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623, Berlin, Germany.
A desymmetrizing silylation of aromatic diols is reported. The previously unknown asymmetric silyl ether formation of phenol derivatives is achieved by applying List's counteranion directed silylation technique. A silylium-ion-like silicon electrophile generated from an allylic silane paired with an imidodiphosphorimidate (IDPi) enables enantioselective discrimination of achiral 1,1'-biaryl-2,6-diols.
View Article and Find Full Text PDFControl of dynamic sp-C stereochemistry.
Nat Chem
May 2023
Department of Chemistry, Durham University, Durham, UK.
Article Synopsis
- Stereogenic sp-hybridized carbon centres are crucial in forming chiral molecules, but they typically require intermolecular reactions for configuration changes, unlike more dynamic motifs.
- The study reveals that certain rigid carbon structures (fluxional carbon cages) can undergo internal enantiomerization via strain-assisted Cope rearrangements, mimicking behaviors seen in more dynamic stereogenic centers.
- These carbon cages not only transmit stereochemical information to their surroundings but also adapt their dynamic properties to influence various chemical processes like catalysis and ion pairing.
Want 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!