Absolute Configuration of (−)-Centratherin, a Sesquiterpenoid Lactone, Defined by Means of Chiroptical Spectroscopy

Fernando, M. S.; Covington, Cody L.; Albuquerque, Ana Carolina Ferreira de; Lobo, Jonathas Felipe Revoredo; Borges, Ricardo Moreira; Amorim, Mauro Barbosa de; Polavarapu, Prasad L.

doi:10.1021/acs.jnatprod.5b00546

Cited by 34 publications

(43 citation statements)

References 41 publications

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“…6 of Ref. 82) can be considered. The appearance of this conservative bisignate couplet, accompanied by a single unresolved absorption band (at 1709 cm -1 ), resembles that expected for molecules supporting the DEC phenomenon, even though the C = O groups in this molecule are not related by symmetry.…”

Section: Nondegenerate Ec (Ndec) Methods For Vcdmentioning

confidence: 99%

“…Structures of ( a ) (2S,3 S )‐dimethyl tartrate; ( b ) (–)‐(6R,7R,8S,10R,2´Z)‐centratherin. The vibrational displacements of two C = O groups, labeled A and B for centratherin, are predicted by B3LYP/aug‐cc‐pVDZ calculations to be responsible for the experimentally observed VCD couplet. The ChemDraw structures are shown at the bottom and 3D drawings are displayed at the top.…”

Section: Interpretational Approaches That Can Lead To the Wrong Pathmentioning

confidence: 96%

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Structural Analysis Using Chiroptical Spectroscopy: Insights and Cautions

Polavarapu

2016

Chirality

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Chiroptical spectroscopy has evolved into a promising tool for chiral molecular structural determination in the last four decades. Determination of the absolute configurations (ACs) of bromochlorofluoromethane and [(2) H1 ,(2) H2 ,(2) H3 ]-neopentane demonstrated the enviable advantages of chiroptical spectroscopy. Furthermore, uncovering the errors in the ACs reported in the literature established a glimpse of what can be accomplished with the modern chiroptical spectroscopic methods. Despite these triumphs, it is important to exercise caution in the practice of chiroptical spectroscopic methods, because certain widely practiced approaches can lead to erroneous conclusions. Selected major accomplishments and special precautions needed for future applications are emphasized. Chirality 28:445-452, 2016. © 2016 Wiley Periodicals, Inc.

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Section: Nondegenerate Ec (Ndec) Methods For Vcdmentioning

confidence: 99%

Section: Interpretational Approaches That Can Lead To the Wrong Pathmentioning

confidence: 96%

Structural Analysis Using Chiroptical Spectroscopy: Insights and Cautions

Polavarapu

2016

Chirality

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“…Additionally, a VCD spectrum using the RSs and DSs in degenerate EC model is simulated for comparison with the full QC predicted spectrum. Example comparisons for spiroindicumide A diacetate and centratherin are shown in Figure . A useful warning here is that the use of the EC model based on dipolar interaction model can yield a wrong conclusion on ACs, and therefore QC analysis is unavoidable …”

Section: Applicationsmentioning

confidence: 99%

CDSpecTech: A single software suite for multiple chiroptical spectroscopic analyses

Covington

Polavarapu

2017

Chirality

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The program CDSpecTech was developed to facilitate the analysis of chiroptical spectra, which include the following: vibrational circular dichroism (VCD) and corresponding vibrational absorption (VA) spectra; vibrational Raman optical activity (VROA) and corresponding vibrational Raman spectra; electronic circular dichroism (ECD) and corresponding electronic absorption (EA) spectra. In addition, the program allows for generating optical rotatory dispersion (ORD) as the Kramers-Kronig transform of ECD spectra. The simulation of theoretical spectra from transition strengths can be achieved using different bandshape profiles. The experimental and simulated theoretical spectra can be visually compared by displaying them together. A unique feature of CDSpecTech is performing spectral analysis using the ratio spectra; i.e., the dimensionless dissymmetry factor (DF) spectrum, which is the ratio of CD to absorption spectra, and the dimensionless circular intensity difference (CID) spectrum, which is the ratio of VROA to vibrational Raman spectra. The quantitative agreement between experimental and simulated theoretical spectra can also be assessed from the numerical similarity overlap between them. Two different similarity overlap methods are available. The program uses a graphical user interface which allows for ease of use and facilitates the analysis. All these features make CDSpecTech a valuable tool for the analysis of chiroptical spectra. The program is freely available on the World Wide Web.

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“…Like its natural analogue, butylone exhibits psychostimulant effects (eg, hyperlocomotion) and causes the increase of extracellular dopamine concentration. [15][16][17][18][19][20][21][22][23][24] The ab initio calculations allow a detailed interpretation of the experimental spectra of chiral molecules in solution. 9 Most studies 11-13 published thus far have been focused on racemic cathinones, and stereo-specific drug interactions have been demonstrated for amphetamines.…”

Section: Introductionmentioning

confidence: 99%

Structure determination of butylone as a new psychoactive substance using chiroptical and vibrational spectroscopies

et al. 2018

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Recently, there has been a worldwide substantial increase in the consumption of new psychoactive substances (NPS), compounds that mimic the structure of illicit drugs, such as amphetamines or ecstasy. The producers try to avoid the law by a slight modification of illicit structures, thereby developing dozens of temporarily legal NPS every year. The current trends in the detection and monitoring of such substances demand a fast and reliable analysis. Molecular spectroscopy represents a highly effective tool for the identification of NPS and chiroptical methods can provide further information on their 3D structure, which is the key for the determination of their biological activity. We present the first systematic study of NPS, specifically butylone, combining chiroptical and vibrational spectroscopies with ab initio calculations. According to density functional theory calculations, 6 stable lowest energy conformers of butylone were found and their molecular structure was described. For each conformer, the relative abundance based on the Boltzmann distribution was estimated, their population weighted spectra predicted and compared to the experimental results. Very good agreement between the experimental and the simulated spectra was achieved, which allowed not only the assignment of the absolute configuration, but also a precise description of the molecular structure.

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Absolute Configuration of (−)-Centratherin, a Sesquiterpenoid Lactone, Defined by Means of Chiroptical Spectroscopy

Cited by 34 publications

References 41 publications

Structural Analysis Using Chiroptical Spectroscopy: Insights and Cautions

Structural Analysis Using Chiroptical Spectroscopy: Insights and Cautions

CDSpecTech: A single software suite for multiple chiroptical spectroscopic analyses

Structure determination of butylone as a new psychoactive substance using chiroptical and vibrational spectroscopies

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