A New Polyoxygenated Steroid from the gorgonian <i>Gorgonella umbraculum</i>

Subrahmanyam, C.; Kumar, Sreekantha Ratna

doi:10.3184/030823400103166878

Cited by 12 publications

(5 citation statements)

References 6 publications

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“…560 Structure elucidation, which included X-ray analysis of 724, 561 necessitated a structural revision of 729 previously reported from Gorgonella umbraculum. 562 Similar conclusions were made by another group working on the same species of gorgonian from the same locale. 563 Their studies led to the determination of absolute configuration of 724 (which they named reticulatin) and 729.…”

Section: Coelenteratessupporting

confidence: 74%

Marine natural products

Blunt¹,

Copp²,

Hu³

et al. 2007

Nat. Prod. Rep.

468

288

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This review covers the literature published in 2005 for marine natural products, with 704 citations (493 for the period January to December 2005) referring to compounds isolated from marine microorganisms and phytoplankton, green algae, brown algae, red algae, sponges, coelenterates, bryozoans, molluscs, tunicates and echinoderms. The emphasis is on new compounds (812 for 2005), together with their 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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Section: Coelenteratessupporting

confidence: 74%

Marine natural products

Blunt¹,

Copp²,

Hu³

et al. 2007

Nat. Prod. Rep.

468

288

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show abstract

“…In this way, errors arising from assignments of configuration based on single NOE correlations may be avoided. Other common single stereocenter misassignments occur at ring junctions, as in the cases of manzacidin B, 74, 75 agelasine C 76, 77 and its epimer, 78 peyssonol A, 79, 80 isoepitaondiol, 81, 82 suberoretisteroid B 83, 84 and the green algal lanostane-type triterpenoid 85, 86 (Table 7), and are caused primarily by NMR spectral overlap. Assignment is also difficult for an isolated substituent on a macrocycle or extended chain, perhaps too far from the point of derivatization in a flexible system.…”

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

166

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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“…The same species, collected from the Vallinukam coast of Tamilnadu, has been recently reported to give four new briarane diterpenoids, umbraculolides A to D, in addition to juncellin, pareolide and others [4,5]. A new polyoxygenated steroid has also been reported from the same species [6]. The ethyl acetate extract of this gorgonian, collected from the Tuticorin coast, furnished a steroid [7] and three known briarane diterpenoids, juncellin, umbraculolides A and D. Further examination of the ethyl acetate extract resulted in the isolation of a new compound, umbraculolide E (1), as a minor constituent.…”

mentioning

confidence: 83%

“…The NMR data for this compound for the lactone and its adjacent groups were almost identical to those of the previously reported compounds. The foregoing correlations, as well as the others listed in Table 1, established the structure and stereochemistry The known briarane diterpenoids isolated, juncellin, umbraculolide A, and umbraculolide D, and the steroid 22-acetoxy-3,25-dihydroxy-16-24,20-24bisepoxy-(3β,16α, 20S, 22R, 24S)-cholest-5-ene, were characterized by comparing their physical and spectral characteristics with the literature data of these compounds [4][5][6][7].…”

mentioning

confidence: 86%

“…The proton H-9 at δ 5.72 connected to C-9, with the acetate group showing correlation with C-2/ C-7/ C-11/ C-17 and C-10, and, similarly, the proton C-14 at The NOESY spectrum (Table 1) did not reveal all the correlations expected, but the few important correlations noticed helped to confirm the stereochemistry of the molecule. The known briarane diterpenoids isolated, juncellin, umbraculolide A, and umbraculolide D, and the steroid 22-acetoxy-3,25-dihydroxy-16-24,20-24bisepoxy-(3β,16α, 20S, 22R, 24S)-cholest-5-ene, were characterized by comparing their physical and spectral characteristics with the literature data of these compounds [4][5][6][7].…”

mentioning

confidence: 99%

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