scholarly journals Model-Free Approach for the Configurational Analysis of Marine Natural Products

Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 283
Author(s):  
Matthias Köck ◽  
Michael Reggelin ◽  
Stefan Immel
Keyword(s):  
Natural Products ◽  
Marine Natural Products ◽  
Distance Geometry ◽  
Manzamine A ◽  
Relative Configuration ◽  
Model Free ◽  
Configurational Analysis ◽  
Model Free Approach ◽  
Initial Starting ◽  
Synthetic Derivatives

The NMR-based configurational analysis of complex marine natural products is still not a routine task. Different NMR parameters are used for the assignment of the relative configuration: NOE/ROE, homo- and heteronuclear J couplings as well as anisotropic parameters. The combined distance geometry (DG) and distance bounds driven dynamics (DDD) method allows a model-free approach for the determination of the relative configuration that is invariant to the choice of an initial starting structure and does not rely on comparisons with (DFT) calculated structures. Here, we will discuss the configurational analysis of five complex marine natural products or synthetic derivatives thereof: the cis-palau’amine derivatives 1a and 1b, tetrabromostyloguanidine (1c), plakilactone H (2), and manzamine A (3). The certainty of configurational assignments is evaluated in view of the accuracy of the NOE/ROE data available. These case studies will show the prospective breadth of application of the DG/DDD method.

scholarly journals The Advanced Floating Chirality Distance Geometry Approach―How Anisotropic NMR Parameters Can Support the Determination of the Relative Configuration of Natural Products

Marine Drugs ◽  
2020 ◽  
Vol 18 (6) ◽  
pp. 330
Author(s):  
Matthias Köck ◽  
Michael Reggelin ◽  
Stefan Immel
Keyword(s):  
Natural Products ◽  
Residual Dipolar Couplings ◽  
Organic Molecules ◽  
Structural Information ◽  
Distance Geometry ◽  
Relative Configuration ◽  
Small Organic Molecules ◽  
Configurational Analysis ◽  
Interproton Distances

The configurational analysis of complex natural products by NMR spectroscopy is still a challenging task. The assignment of the relative configuration is usually carried out by analysis of interproton distances from NOESY or ROESY spectra (qualitative or quantitative) and scalar (J) couplings. About 15 years ago, residual dipolar couplings (RDCs) were introduced as a tool for the configurational determination of small organic molecules. In contrast to NOEs/ROEs which are local parameters (distances up to 400 pm can be detected for small organic molecules), RDCs are global parameters which allow to obtain structural information also from long-range relationships. RDCs have the disadvantage that the sample needs a setup in an alignment medium in order to obtain the required anisotropic environment. Here, we will discuss the configurational analysis of five complex natural products: axinellamine A (1), tetrabromostyloguanidine (2), 3,7-epi-massadine chloride (3), tubocurarine (4), and vincristine (5). Compounds 1–3 are marine natural products whereas 4 and 5 are from terrestrial sources. The chosen examples will carefully work out the limitations of NOEs/ROEs in the configurational analysis of natural products and will also provide an outlook on the information obtained from RDCs.

The discoipyrroles: A multifaceted approach to understand a novel family of marine natural products

Planta Medica ◽  
2015 ◽  
Vol 81 (11) ◽  
Author(s):  
DA Colosimo ◽  
F Cai ◽  
Y Hu ◽  
MB Potts ◽  
MA White ◽  
...  
Keyword(s):  
Natural Products ◽  
Marine Natural Products ◽  
Multifaceted Approach

Synthesis of Marine Natural Products 1

1992 ◽  
Author(s):  
K. F. Albizati ◽  
V. A. Martin ◽  
M. R. Agharahimi ◽  
D. A. Stolze
Keyword(s):  
Natural Products ◽  
Marine Natural Products

Synthesis and Biological Evaluation of the Antimicrobial Natural Product Lipoxazolidinone A

2018 ◽  
Author(s):  
Jonathan J. Mills ◽  
Kaylib R. Robinson ◽  
Troy E. Zehnder ◽  
Joshua G. Pierce
Keyword(s):  
Natural Products ◽  
Natural Product ◽  
Mechanism Of Action ◽  
Marine Natural Products ◽  
Biological Evaluation ◽  
Lead Compounds ◽  
Follow Up Studies ◽  
Initial Resistance ◽  
Synthesis And Biological Evaluation

The lipoxazolidinone family of marine natural products, with an unusual 4-oxazolidinone heterocycle at their core, represents a new scaffold for antimicrobial discovery; however, questions regarding their mechanism of action and high lipophilicity have likely slowed follow-up studies. Herein, we report the first synthesis of lipoxazolidinone A, 15 structural analogs to explore its active pharmacophore, and initial resistance and mechanism of action studies. These results suggest that 4-oxazolidinones are valuable scaffolds for antimicrobial development and reveal simplified lead compounds for further optimization.

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