Aplysiols C - E, Brominated Triterpene Polyethers from the Marine Alga Chondria armata and a Revision of the Structure of Aplysiol B

Ola, Antonius R. B.; Babey, Anna‐Marie; Motti, Cherie A.; Bowden, Bruce F.

doi:10.1071/ch10081

Cited by 18 publications

(16 citation statements)

References 22 publications

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“…[28] According to those proposals, oxasqualenoids are formed as the result of a series of concerted cyclization reactions with inversion at one center and retention at the other. [29] In fact, this result is also the case in compound 1, where alternating relative configurations (6S*,7R*, 10R*,11S*; 14R*,15S*; and 18R*,19S*) are observed at those positions that should be derived from the precursor epoxides (Scheme 1).…”

Section: Ja C H T U N G T R E N N U N G (Hh) and 23 Ja C H T U N G mentioning

confidence: 68%

Connecting Discrete Stereoclusters by Using DFT and NMR Spectroscopy: The Case of Nivariol

Cen-Pacheco

Rodrı́guez

Norte

et al. 2013

Chemistry A European J

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The structural determination of small organic molecules is mainly undertaken by using NMR techniques, although it is increasingly supplemented by using computational methods. NMR parameters, such as chemical shifts and coupling constants, are extremely sensitive indicators of local molecular conformation and are a source of structural evidence. However, their interpretation is fairly challenging in many circumstances, such as the case of the new polyether squalene derivative nivariol, the structure of which was elucidated by means of NMR spectroscopy and DFT calculations. The potential flexibility of this molecule and the high number of quaternary carbon atoms that it contains make its configurational assignment very difficult. Moreover, the relative configuration of four separated stereoclusters was established and subsequently connected by using NOE and J-based analysis, as well as by a comparison of its experimental (13)C NMR chemical shifts with the corresponding population-weighted values, as calculated by using DFT methods. Limitations of these used approaches became apparent but were overcome by combining the two methods.

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Section: Ja C H T U N G T R E N N U N G (Hh) and 23 Ja C H T U N G mentioning

confidence: 68%

Connecting Discrete Stereoclusters by Using DFT and NMR Spectroscopy: The Case of Nivariol

Cen-Pacheco

Rodrı́guez

Norte

et al. 2013

Chemistry A European J

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“…530 These compounds share a signicant part of their structures with aplysiol B, and with the denition of the stereocentre congurations in the saiyacenols well established, it was possible to conrm with more certainty the recently proposed structural revision for aplysiol B. 531 Bromophenols are frequently reported from red algae, and an additional 13 were described in 2012. The potently radical scavenging bromophenols 525-529 were obtained from Rhodomela confervoides (Dalian, Liaoning Province, China).…”

Section: Red Algaementioning

confidence: 98%

Marine natural products

et al. 2014

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This review covers the literature published in 2012 for marine natural products, with 1035 citations (673 for the period January to December 2012) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1241 for 2012), together with the relevant biological activities, source organisms and country of origin. Biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.

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“…Structural motifs misassigned on the basis of NOEs include epoxides (calafianin, 96–98 symbiodinolide 99, 100 ), cyclopropyl rings (clavosolide A, 101, 102 laurentristich-4-ol 103, 104 ), bridges (vannusals A and B 105–107 ), fused ring junctions (itomanallene A, 108, 109 asperdimin, 110, 111 aplysiallene 112, 113 ), polyethers (aplysiol B, 114, 115 azaspiracids 116–119 ), vicinal polyols (amphidinolide H2, 120, 121 hyrtiosterol, 122, 123 pericosine A 124, 125 ), sugars (callipeltoside C; 126, 127 fusapyrone and deoxyfusapyrone, 128, 129 Table 6) and macrolides (palmerolide A, 130–132 neopeltolide 133, 134 ).…”

Section: Sources Of Natural Product Structural Misassignmentsmentioning

confidence: 99%

Survey of marine natural product structure revisions: A synergy of spectroscopy and chemical synthesis

Suyama

Gerwick

McPhail

2011

Bioorganic & Medicinal Chemistry

164

175

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The structural assignment of new natural product molecules supports research in a multitude of disciplines that may lead to new therapeutic agents and or new understanding of disease biology. However, reports of numerous structural revisions, even of recently elucidated natural products, inspired the present survey of techniques used in structural misassignments and subsequent revisions in the context of constitutional or configurational errors. Given the comparatively recent development of marine natural products chemistry, coincident with the modern spectroscopy, it is of interest to consider the relative roles of spectroscopy and chemical synthesis in the structure elucidation and revision of those marine natural products which were initially misassigned. Thus, a tabulated review of all marine natural product structural revisions from 2005 to 2010 is organized according to structural motif revised. Misassignments of constitution are more frequent than perhaps anticipated by reliance on HMBC and other advanced NMR experiments, especially considering the full complement of all natural products. However, these techniques also feature prominently in structural revisions, specifically of marine natural products. Nevertheless, as is the case for revision of relative and absolute configuration, total synthesis is a proven partner for marine, as well as terrestrial, natural products structure elucidation. It also becomes apparent that considerable ‘detective work’ remains in structure elucidation, in spite of the spectacular advances in spectroscopic techniques.

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Aplysiols C - E, Brominated Triterpene Polyethers from the Marine Alga Chondria armata and a Revision of the Structure of Aplysiol B

Cited by 18 publications

References 22 publications

Connecting Discrete Stereoclusters by Using DFT and NMR Spectroscopy: The Case of Nivariol

Connecting Discrete Stereoclusters by Using DFT and NMR Spectroscopy: The Case of Nivariol

Marine natural products

Survey of marine natural product structure revisions: A synergy of spectroscopy and chemical synthesis

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