Reducing Molecular Flexibility by Cyclization for Elucidation of Absolute Configuration by CD Calculations: Daurichromenic Acid

Mándi, Attila; Swamy, Mahadeva M. M.; Taniguchi, Tohru; Anetai, Masaki; Monde, Kenji

doi:10.1002/chir.22606

Cited by 21 publications

(29 citation statements)

References 52 publications

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“…This derivatization strategy reduced the molecular flexibility and allowed the AC assignment of meroterpenoid (-)−122 ( Figure 31) by ECD and VCD as (5R,8S,10R). 68 Two hoursighly oxygenated nortriterpenoids, picraviane A (123) and B (124) ( Figure 32) were isolated from Picramnia glazioviana Engl and their structures determined by NMR. Single-crystal X-ray diffraction data were also obtained for picraviane B.…”

Section: Monoterpenoids the Formulas Of The 28 Monoterpenoids Includmentioning

confidence: 99%

Vibrational Circular Dichroism Absolute Configuration of Natural Products From 2015 to 2019

Río

Joseph‐Nathan

2021

Natural Product Communications

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Although demonstrated in 1975, vibrational circular dichroism (VCD) finally started to popularize during this century as a reliable tool to determine the absolute configuration (AC) of organic molecules. This research field continues to be a very dynamic one, in particular for the study of natural products which are a unlimited source of chiral molecules. It therefore turns of interest to summarize the accomplishments published in recent years and to comment on some eventual difficulties that emerged in rare cases to complete the AC determination task. Therefore the aim of this review is to update VCD results for the AC assignment of natural products published from 2015 to 2019, a period in which VCD was reported in some 126 publications involving almost 300 molecules. They are organized according the type of studied metabolite allowing an easily search. The molecules correspond to 28 monoterpenes concerning 17 papers, to 42 sesquiterpenes in 14 papers, to 51 diterpenes in 19 publications, to 5 other terpenoids in three papers, to 48 aromatic molecules in 15 reports, to 20 polyketides in 10 publications, to 27 miscellaneous formulas also in 10 papers, and to 76 nitrogen containing compounds, which include alkaloids and their synthetic analogs, in 38 articles. The landscape of reviewed molecules is quite wide as it goes from simple monoterpenes, like borneol or camphor, to very relevant biological molecules like the alkaloid cocaine or tadalafil samples to distinguish genuine and counterfeit Cialis®. In addition, 5 natural products and a simple derivative published outside the reviewed period, were used to illustrate some aspects of density functional theory calculations.

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Section: Monoterpenoids the Formulas Of The 28 Monoterpenoids Includmentioning

confidence: 99%

Vibrational Circular Dichroism Absolute Configuration of Natural Products From 2015 to 2019

Río

Joseph‐Nathan

2021

Natural Product Communications

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“…The identity of DCA ( 1 ) isolated from Rhododendron dauricum was confirmed by 1 H- and 13 C-nuclear magnetic resonance (NMR) and by electrospray ionization-mass spectrometry (ESI-MS) and compared with previously reported values [ 22 ]. To understand the structure–activity relationship (SAR) between DCA and its target molecules, DCA derivatives were synthesized.…”

Section: Resultsmentioning

confidence: 78%

Daurichromenic Acid from the Chinese Traditional Medicinal Plant Rhododendron dauricum Inhibits Sphingomyelin Synthase and Aβ Aggregation

et al. 2020

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Species of the genus Rhododendron have been used in traditional Chinese medicine, with the medicinal herb “Manshanfong” used as an expectorant and for the treatment of acute bronchitis. Daurichromenic acid (DCA), a constituent of Rhododendron dauricum, is a meroterpenoid with antibacterial, anti-HIV, and anti-inflammatory activities. However, the mechanisms underlying these pharmacologic activities are poorly understood. To develop new drugs based on DCA, more information is required regarding its interactions with biomolecules. The present study showed that DCA inhibits the activity of the enzyme sphingomyelin synthase, with an IC50 of 4 µM. The structure–activity relationships between DCA and sphingomyelin synthase were evaluated using derivatives and cyclized hongoquercin A. In addition, DCA was found to inhibit amyloid β aggregation. These results may help in the design of effective drugs based on DCA.

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“…For the configurational assignment of 1 , the solution TDDFT‐ECD method was applied on the arbitrarily chosen ( S ) stereoisomer . Since 1 is conformationally flexible and the relative orientation of the three aromatic chromophores produced by rotation along the C‐3‐C‐13 biaryl axis and the sigma bonds of the C‐6 chirality center is expected to be fundamental for the sign and shape of the ECD transitions, a thorough conformational search is inevitable . Consequently, the initial 37 MMFF conformers of ( S )‐ 1 were reoptimized at both the ωB97X/TZVP PCM/MeCN and the SOGGA11‐X/TZVP SMD/MeCN levels of theory .…”

Section: Resultsmentioning

confidence: 99%

Furoic acid derivatives from the endophytic fungus Coniothyrium sp.

et al. 2020

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The endophytic fungus Coniothyrium sp. was isolated from leaves of Quercus robur. Fermentation of this fungus on solid rice medium yielded two new furoic acid derivatives (1 and 2) and two additional known compounds. The structures of the new compounds were determined by extensive analysis of 1D and 2D nuclear magnetic resonance spectra as well as high-resolution mass spectrometry data. Compound 1, containing three aromatic chromophores attached by rotatable sigma bonds and a chirality center in benzylic position, was found to be a scalemic mixture with an excess of the (S) enantiomer, the absolute configuration of which was elucidated as by the solution timedependent density functional theory-electronic circular dichroism approach. The ωB97X/TZVP PCM/MeCN and SOGGA11-X/TZVP SMD/MeCN methods were used for geometry reoptimization to reproduce the solution conformational ensemble. All isolated compounds were tested for their cytotoxicity but proved to be inactive. K E Y W O R D SConiothyrium sp, electronic circular dichroism, furoic acid derivatives, TDDFT-ECD calculation

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Reducing Molecular Flexibility by Cyclization for Elucidation of Absolute Configuration by CD Calculations: Daurichromenic Acid

Cited by 21 publications

References 52 publications

Vibrational Circular Dichroism Absolute Configuration of Natural Products From 2015 to 2019

Vibrational Circular Dichroism Absolute Configuration of Natural Products From 2015 to 2019

Daurichromenic Acid from the Chinese Traditional Medicinal Plant Rhododendron dauricum Inhibits Sphingomyelin Synthase and Aβ Aggregation

Furoic acid derivatives from the endophytic fungus Coniothyrium sp.

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