Will Climate Change Influence Production and Environmental Pathways of Halogenated Natural Products?

2020 ◽  
Vol 54 (11) ◽  
pp. 6468-6485 ◽  
Author(s):  
Terry F. Bidleman ◽  
Agneta Andersson ◽  
Peter Haglund ◽  
Mats Tysklind
Keyword(s):  
Climate Change ◽  
Natural Products ◽  
Halogenated Natural Products

Occurrence of halogenated natural products in highly consumed fish from polluted and unpolluted tropical bays in SE Brazil

2018 ◽  
Vol 242 ◽  
pp. 684-691 ◽  
Author(s):  
L.F. Estrella ◽  
V.B. Ferreira ◽  
C. Gallistl ◽  
M.G.R. Alves ◽  
W. Vetter ◽  
...  
Keyword(s):  
Natural Products ◽  
Se Brazil ◽  
Halogenated Natural Products

scholarly journals Halonium-Induced Polyene Cyclizations

Synthesis ◽  
2019 ◽  
Vol 51 (08) ◽  
pp. 1753-1769 ◽  
Author(s):  
Agathe D’Hollander ◽  
Laure Peilleron ◽  
Tatyana Grayfer ◽  
Kevin Cariou
Keyword(s):  
Natural Products ◽  
Total Synthesis ◽  
Asymmetric Reactions ◽  
Recent Developments ◽  
Halogenated Natural Products

This review covers the methods that chemists have developed to access halogenated polycyclic structures from polyenes, by emulating Nature’s enzymatic machineries. From pioneering studies to the most recent developments, the different strategies, whether based on the use of standard reagents or on the design of specific ones, will be presented. Finally, asymmetric reactions and applications for the total synthesis of natural products will be exposed.1 Introduction2 Pioneering Studies3 Use of Specific Reagents4 Use of N-Haloamides5 Asymmetric Reactions6 Total Synthesis of Halogenated Natural Products7 Conclusion and Perspectives

The value of managing for biodiversity

1992 ◽  
Vol 68 (2) ◽  
pp. 225-237 ◽  
Author(s):  
P. J. Burton ◽  
A. C. Balisky ◽  
L. P. Coward ◽  
D. D. Kneeshaw ◽  
S. G. Cumming
Keyword(s):  
Climate Change ◽  
Natural Products ◽  
Environmental Ethics ◽  
Biological Diversity ◽  
Genetic Material ◽  
Ecological Indicators ◽  
Individual Species ◽  
Multiple Use ◽  
Integrated Resource Management ◽  
Management Indicator Species

The concept of biological diversity (biodiversity) is reviewed, with special attention to its measurement and natural trends. While generalizations regarding the necessity of biodiversity need to be interpreted with caution, it is argued that biodiversity should be protected in more ecosystem and landscape reserves, and that biodiversity is a reasonable management objective on timber lands as well. Maintaining biodiversity is important because we cannot always identify which individual species are critical to ecosystem sustainability, nor which species may be useful to mankind in future. Many wild species can provide useful natural products and genetic material, and can serve as ecological indicators. Diversity reduces pest and disease problems, and encourages recovery from disturbance. Uncertainty exists with regard to climate change and future socioeconomic values. It is therefore prudent to maximize flexibility by promoting a wide array of species and potential products. Suggestions are offered on how to promote biodiversity in multiple-use forests. Key words: biological diversity, climate change, environmental ethics, forest inventory, genetic conservation, integrated resource management, indicator species, landscape ecology, multiple-use, natural products, stability, uncertainty.

Capturing Nature's Oxonium Ions

2019 ◽  
Author(s):  
Hau Sun (Sam) Chan ◽  
Q. Nhu. N. Nguyen ◽  
Jonathan Burton ◽  
Robert Paton
Keyword(s):  
Natural Products ◽  
Direct Evidence ◽  
Alkylating Agents ◽  
Reactive Intermediates ◽  
Total Syntheses ◽  
Oxonium Ions ◽  
Halogenated Natural Products

<p><a></a>Acetylcholine and <i>S</i>-adenosylmethionine exemplify the tetraalkylammonium (R<sub>4</sub>N<sup>+</sup>) and trialkylsulfonium (R<sub>3</sub>S<sup>+</sup>) ions used by Nature. The corresponding trialkyloxonium ions (R<sub>3</sub>O<sup>+</sup>), however, do not play a central role in biology most likely due to their hydrolytic instability compared with their ammonium and sulfonium counterparts. Indeed, Meerwein’s salts [(CH<sub>3</sub>)<sub>3</sub>O<sup>+</sup>BF<sub>4</sub><sup>–</sup> and (CH<sub>3</sub>CH<sub>2</sub>)<sub>3</sub>O<sup>+</sup>BF<sub>4</sub><sup>–</sup>], the simplest of the trialkyloxonium ions, are among the most powerful alkylating agents known, and they too are unstable to water. Only recently have water stable trialkyloxonium ions been reported which contain an oxatriquinane skeleton. Interestingly, despite the inherent hydrolytic instability of the vast majority of trialkyloxonium ions, they have been postulated as key intermediates in the biosynthesis of a number of complex natural products from <i>Laurencia</i> species. The existence of these complex trialkyloxonium ions has been implied from the structural and stereochemical diversity of these natural products and is supported by elegant biomimetic total syntheses, yet no direct evidence for their existence has been forthcoming. Herein, we report the synthesis and full characterisation of one family of these biosynthetically relevant trialkyloxonium ions - the most structurally and stereochemically complex oxonium ions characterised to date. Additionally, the elucidation of their <i>in vitro </i>reactivity profile has resulted in the synthesis of more than ten complex halogenated natural products. This work substantiates the existence of complex trialkyloxonium ions as key reactive intermediates in the biosynthesis of numerous halogenated natural products from <i>L. </i>spp. – expanding Nature’s rich inventory of onium ions.</p>

scholarly journals Powerful GC-TOF-MS Techniques for Screening, Identification and Quantification of Halogenated Natural Products

2013 ◽  
Vol 2 (Special_Issue) ◽  
pp. S0018-S0018 ◽  
Author(s):  
Peter S. Haglund ◽  
Karin Löfstrand ◽  
Kevin Siek ◽  
Lillemor Asplund
Keyword(s):  
Natural Products ◽  
Halogenated Natural Products ◽  
Tof Ms ◽  
Identification And Quantification
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