The mass spectrometric behavior of phenanthroindolizidine alkaloids has been investigated in detail by positive ion fast atom bombardment tandem mass spectrometry (FAB-MS/MS) combined with collision-induced dissociation (CID). The fragmentation has been correlated with the skeleton structure and positions of substituents. The product ions arising from retro-Diels-Alder cleavages differ clearly for compounds with different skeletons. The substituents at C-14 were observed to markedly influence the fragmentation pathway of [M + H](+) ions. A diversity of dissociation behavior initiated by the variation of substituents on the aromatic ring was also observed in the CID spectra. Product ions resulting from loss of CH(4) were obtained for compounds in which both C-6 and C-7 are occupied by methoxy groups. FAB-MS/MS spectra can reflect the connection between the fragmentation behavior and structural features of these phenanthroindolizidine alkaloids rapidly and effectively, and should prove to be a powerful method to determine the structures of related compounds.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1002/rcm.766 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Laser Synthesis of Platinum Single-Atom Catalysts for Hydrogen Evolution Reaction.
Nanomaterials (Basel)
January 2025
Department of Materials, School of Natural Science, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
Platinum (Pt)-based heterogeneous catalysts show excellent performance for the electrocatalytic hydrogen evolution reaction (HER); however, the high cost and earth paucity of Pt means that efforts are being directed to reducing Pt usage, whilst maximizing catalytic efficiency. In this work, a two-step laser annealing process was employed to synthesize Pt single-atom catalysts (SACs) on a MOF-derived carbon substrate. The laser irradiation of a metal-organic framework (MOF) film (ZIF67@ZIF8 composite) by rapid scanning of a ns pulsed infrared (IR; 1064 nm) laser across the freeze-dried MOF resulted in a metal-loaded graphitized film.
View Article and Find Full Text PDFBone Turnover Markers Predict Changes in Bone Mineral Density in Men Treated with Abaloparatide: Results from ATOM.
J Bone Miner Res
January 2025
Radius Health Inc, Boston, MA, United States.
Early increases in bone turnover markers (BTMs) in response to anabolic therapy correlate with 18-month bone mineral density (BMD) increases in postmenopausal women with osteoporosis; however, this relationship has not been assessed in men. In this analysis, the correlation between changes from baseline in fasting intact serum procollagen type I N propeptide (PINP) and serum carboxy-terminal cross-linking telopeptide of type I collagen (CTX) at 1, 3, 6, and 12 months and percent increase from baseline in BMD at 12 months in men from the randomized phase 3 ATOM study (NCT03512262) were evaluated using Pearson's correlation coefficients. The uncoupling index (UI), a measure of the balance between markers of bone formation (PINP) and bone resorption (CTX), with positive UI favoring bone formation, was calculated.
View Article and Find Full Text PDFFlowBack: A Generalized Flow-Matching Approach for Biomolecular Backmapping.
J Chem Inf Model
January 2025
Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States.
Coarse-grained models have become ubiquitous in biomolecular modeling tasks aimed at studying slow dynamical processes such as protein folding and DNA hybridization. These models can considerably accelerate sampling but it remains challenging to accurately and efficiently restore all-atom detail to the coarse-grained trajectory, which can be vital for detailed understanding of molecular mechanisms and calculation of observables contingent on all-atom coordinates. In this work, we introduce FlowBack as a deep generative model employing a flow-matching objective to map samples from a coarse-grained prior distribution to an all-atom data distribution.
View Article and Find Full Text PDFFacile Synthetic Access Towards Sulfur- and Selenium-Functionalized Boron-Based Multiresonance TADF Emitters.
Molecules
December 2024
Department of Inorganic and Analytical Chemistry, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany.
Thermally activated delayed fluorescence (TADF) materials with high photoluminescence quantum yields and a fast reverse intersystem crossing (RISC) are of the highest interest for organic light-emitting diodes (OLEDs). In the past decade, triaryl boranes with multiple resonance effect (MR) have captured significant attention. The efficiency of MR-TADF emitters strongly depends on small singlet-triplet energy gaps (ΔE), but also on large reverse intersystem crossing (RISC) rate constants (k).
View Article and Find Full Text PDFTransforming Plastics to Single Atom Catalysts for Peroxymonosulfate Activation: Axial Chloride Coordination Intensified Electron Transfer Pathway.
Adv Mater
January 2025
School of Chemical Engineering, The University of Adelaide, Adelaide, SA, 5005, Australia.
Article Synopsis
- Transforming waste plastics into valuable materials can be achieved by creating graphene-based single-atom catalysts using high-density polyethylene via catalytic pyrolysis.
- The catalyst, featuring dispersed FeNCl sites, shows significantly improved performance compared to similar catalysts without chloride, due to enhanced conductivity and efficiency in activating peroxymonosulfate (PMS).
- Techniques like Raman and infrared spectroscopy confirm that the catalyst efficiently degrades pollutants through a non-radical oxidation process, making it suitable for continuous water treatment applications.
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!