Absolute configuration of (−)-myrtenal by vibrational circular dichroism

Burgueño‐Tapia, Eleuterio; Zepeda, L. Gerardo; Joseph‐Nathan, Pedro

doi:10.1016/j.phytochem.2010.04.005

Cited by 41 publications

(40 citation statements)

References 23 publications

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“…This functional has been used successfully when calculating some molecules possessing an aromatic ring, like epoxythymols and an aporphine alkaloid, for which the anharmonicity factor was always above the unit, specifically in the 1.002‐1.020 range. Anharmonicity factors above the unit are not exclusive for the PBEPBE functional, as a 1.007 value became evident when myrtenal was calculated at the B3PW91/DGTZVP level of theory . The VCD spectroscopic similarities for the correct enantiomer ( S E ) was 70.8, while that for the incorrect enantiomer ( S −E ) was 9.9.…”

Section: Resultssupporting

confidence: 88%

“…Anharmonicity factors above the unit are not exclusive for the PBEPBE functional, as a 1.007 value became evident when myrtenal was calculated at the B3PW91/DGTZVP level of theory. 44 The VCD spectroscopic similarities for the correct enantiomer (S E ) was 70.8, while that for the incorrect enantiomer (S −E ) was 9.9. The enantiomer similarity index (ESI), obtained by the S E − S −E difference was 60.8, and the data indicated a 100% confidence level (C) for the AC of (−)-(R)-podocephalyl acetate (2) and consequently its precursor is (+)-(7R)-podocephalol (1).…”

Section: Resultsmentioning

confidence: 96%

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Conformational, configurational, and supramolecular studies of podocephalol acetate from Lasianthaea aurea

et al. 2019

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Although podocephalol (1) and its derived acetate 2 were found in Lasianthaea podocephala four decades ago, and 1 was later detected in the essential oils of several vegetal species, its absolute configuration (AC) and conformational preferences remained to be established. The structures of ar‐himachalene 1, now isolated from Lasianthaea aurea, and its derived acetate 2, were herein confirmed by extensive 1D and 2D nuclear magnetic resonance (NMR) studies, while the conformational preferences of the cycloheptene was established by density functional theory (DFT) calculations, which in combination with vibrational circular dichroism measurements provided the (R) absolute configuration of the molecules. The structure and AC were further verified through the Flack and Hooft parameters calculations derived from single crystal X‐ray diffraction data of 2. In addition, careful evaluation of the crystal data allowed observing supramolecular layers cell package, an uncommon property in natural terpenes that might have potential applications. A transmission electron microscopy analysis of crystal of 2 was also possible, providing its physical characteristics at the micrometric scale.

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Section: Resultssupporting

confidence: 88%

Section: Resultsmentioning

confidence: 96%

Conformational, configurational, and supramolecular studies of podocephalol acetate from Lasianthaea aurea

et al. 2019

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“…Thus, the latter data are normally scaled using an anharmonicity factor which was obtained using the commercial available confidence level algorithm software (BioTools Co., Jupiter, FL, 33458 USA) based on neighbourhood similarity 29 that we recently applied for the study of 1 R -(−)-myrtenal at several levels of theory. 30 This algorithm uses a correlation function that describes the integrated overlap of the experimental and theoretical data as a function of a relative vibrational frequency shift, being the optimal shift known as the anharmonicity ( anH ) factor. Taking advantage of this methodology, the calculated spectra of both diastereomers were compared in silico to the experimental IR and VCD spectra of 1 , the pertinent results being summarized in Table 4.…”

Section: Resultsmentioning

confidence: 99%

Stereochemical Analysis of Leubethanol, an Anti-TB-Active Serrulatane, fromLeucophyllum frutescens

et al. 2011

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Bioactivity-guided fractionation of the methanolic root bark extract of Leucophyllum frutescens (Berl.) I.M. Johnst. led to the identification of leubethanol (1), a new serrulatane-type diterpene with activity against both multi drug-resistant and drug-sensitive strains of virulent Mycobacterium tuberculosis. Leubethanol (1) was identified by 1D/2D NMR data, as a serrulatane closely related to erogorgiane (2), and exhibited anti-TB activity with minimum inhibitory concentrations in the range 6.25–12.50 µg/mL. Stereochemical evidence for 1 was gleaned from 1D and 2D NOE experiments, 1H-NMR full spin analysis, as well as by comparison of the experimental vibrational circular dichroism (VCD) spectrum to density functional theory calculated VCD spectra of two diastereomers.

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“…Anharmonicity factors were calculated with the Compare VOA software package and used to scale frequency values of IR and VCD spectra. We have extensively used this program since 2010, through the courtesy of BioTools, and have always obtained valuable results over the years.…”

Section: Methodsmentioning

confidence: 99%

Vibrational Circular Dichroism Discrimination of Diastereomeric Cedranol Acetates

Gordillo-Román¹,

Camacho-Ruiz²,

Bucio³

et al. 2013

Chirality

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The reliability of vibrational circular dichroism (VCD) spectroscopy to discriminate four diastereomeric cedranol acetates 1-4 by means of their absolute configuration is examined. The usage of CompareVOA software to quantify comparisons of the measured infrared (IR) and VCD spectra with the corresponding simulated spectra at the B3LYP/DGDZVP and B3PW91/DGDZVP levels of theory for each diastereomer enabled the B3PW91 functional to be qualified as superior to the B3LYP functional for vibrational calculations of 1-4. Analogously, a set of quantitative VCD spectra cross-comparisons of 1-4 unambiguously distinguished the diastereomers using B3PW91 and failed using B3LYP. Remarkably, quantitative IR spectra cross-comparisons of 1-4 using B3PW91 or B3LYP functionals demonstrated that the achiral spectroscopic IR technique is not able to distinguish cedranol acetate diastereomers. VCD comparisons using anisotropy g-factor values of bands in the 1550-950 cm(-1) region of the spectra were of aid to facilitate visual spectra matching for each diastereomer.

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Absolute configuration of (−)-myrtenal by vibrational circular dichroism

Cited by 41 publications

References 23 publications

Conformational, configurational, and supramolecular studies of podocephalol acetate from Lasianthaea aurea

Conformational, configurational, and supramolecular studies of podocephalol acetate from Lasianthaea aurea

Stereochemical Analysis of Leubethanol, an Anti-TB-Active Serrulatane, fromLeucophyllum frutescens

Vibrational Circular Dichroism Discrimination of Diastereomeric Cedranol Acetates

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