Structural revisions of natural products by total synthesis

Maier, Martin E.

doi:10.1039/b809658a

Cited by 210 publications

(114 citation statements)

References 122 publications

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“…The latter example in particular illustrates the development of new synthetic methodologies in the pursuit of molecular structures. A detailed and comprehensive 2009 review by Maier 7 extends this discussion of the role of total synthesis in the structural revision of natural products, highlighting a sustained rate of structural reassignments from 2005 to 2009. Maier also breaks down the types or sources of misassignments into subcategories of incorrect formula, constitution (planar connectivity), double bond configuration, absolute configuration, and one or several stereocenters assigned incorrectly, providing comprehensive treatment of numerous case studies.…”

Section: Introductionmentioning

confidence: 91%

“…22, 23 In these three compounds, the observed 13 C NMR shifts of the oxygen-bearing carbons were more consistent with a 2,2′-bifuranyl moiety (> 76 ppm) than the proposed pyrano[3,2- b ]pyran (< 76 ppm). 7 Consideration of these structures elicits the question of whether these errors may be attributed to the assignment of observed HMBC correlations as 4-bond connections. An alternative scenario is that key 3-bond HMBC correlations were absent, presumably because they were outside the coupling constant range detectable in a standard HMBC experiment optimized for 3 J CH = 8 Hz.…”

Section: Sources Of Natural Product Structural Misassignmentsmentioning

confidence: 99%

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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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Section: Introductionmentioning

confidence: 91%

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

View full text Add to dashboard Cite

show abstract

“…In average, per 5-year period, 369 NP and 135 MNP are misassigned [58]. The structural complexity of the isolated compounds and the small amount of samples, especially in the case of compounds from marine sources, can contribute to misassignments which can be divided in several categories: incorrect formula, constitution (planar connectivity), double bond configuration, absolute configuration, and one or several stereocenters assigned incorrectly [59]. …”

Section: Challenges Faced During Marine Natural Products Developmentmentioning

confidence: 99%

Marketed Marine Natural Products in the Pharmaceutical and Cosmeceutical Industries: Tips for Success

Martins¹,

et al. 2014

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The marine environment harbors a number of macro and micro organisms that have developed unique metabolic abilities to ensure their survival in diverse and hostile habitats, resulting in the biosynthesis of an array of secondary metabolites with specific activities. Several of these metabolites are high-value commercial products for the pharmaceutical and cosmeceutical industries. The aim of this review is to outline the paths of marine natural products discovery and development, with a special focus on the compounds that successfully reached the market and particularly looking at the approaches tackled by the pharmaceutical and cosmetic companies that succeeded in marketing those products. The main challenges faced during marine bioactives discovery and development programs were analyzed and grouped in three categories: biodiversity (accessibility to marine resources and efficient screening), supply and technical (sustainable production of the bioactives and knowledge of the mechanism of action) and market (processes, costs, partnerships and marketing). Tips to surpass these challenges are given in order to improve the market entry success rates of highly promising marine bioactives in the current pipelines, highlighting what can be learned from the successful and unsuccessful stories that can be applied to novel and/or ongoing marine natural products discovery and development programs.

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“…C H 3 Figure 12.9 The top ranked structures of the output file generated by the StrucEluc software for the C 20 H 23 N 3 O 4 compound (-)-spiroleucettadine elucidated from the 2D NMR data obtained by Ralifo and Crews. 22 The numbers in the top left of each box are rank numbers.…”

Section: 11mentioning

confidence: 99%

Structural Revisions of Natural Products with the Aid of the Structure Elucidator System

2011

Contemporary Computer-Assisted Approaches to Molecular Structure Elucidation

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Every year a number of articles are published that contain incorrectly elucidated structures. Based on our experience with the application of CASE systems it is expected that such software and algorithms can help the chemist in the elucidation process or can at least provide warnings for structures suggested by scientists. This chapter therefore reviews the application of CASE to a series of examples for which the original structures were later revised. It is demonstrated that the chemical structure can be correctly elucidated if 2D NMR data were available and the expert system Structure Elucidator is employed. It is also shown that if only 1D NMR spectra from the original articles were used then simply the calculation of the 13C chemical shifts for the hypothetical structures frequently allows a scientist to realize that the structural hypothesis is likely incorrect.

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Structural revisions of natural products by total synthesis

Cited by 210 publications

References 122 publications

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

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

Marketed Marine Natural Products in the Pharmaceutical and Cosmeceutical Industries: Tips for Success

Structural Revisions of Natural Products with the Aid of the Structure Elucidator System

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