Computational prediction of chiroptical properties in structure elucidation of natural products

Grauso, Laura; Teta, Roberta; Esposito, Germana; Menna, Marialuisa; Mangoni, Alfonso

doi:10.1039/c9np00018f

Cited by 81 publications

(91 citation statements)

References 106 publications

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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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Section: Resultsmentioning

confidence: 99%

Furoic acid derivatives from the endophytic fungus Coniothyrium sp.

et al. 2020

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“…We, as well as other authors, demonstrated that most of the traditional empirical correlation rules are inadequate and often incorrect and may lead to wrong conclusions [ 57 , 58 , 59 ]. Solving the Rosenfeld equation of optically active electron transitions, with the use of modern theoretical methods, mostly the DFT-based one is an alternative to the empirical rules [ 60 , 61 , 62 , 63 , 64 , 65 ].…”

Section: Resultsmentioning

confidence: 99%

Synthesis, Absolute Configuration, Antibacterial, and Antifungal Activities of Novel Benzofuryl β-Amino Alcohols

et al. 2020

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A series of new benzofuryl α-azole ketones was synthesized and reduced by asymmetric transfer hydrogenation (ATH). Novel benzofuryl β-amino alcohols bearing an imidazolyl and triazolyl substituents were obtained with excellent enantioselectivity (96–99%). The absolute configuration (R) of the products was confirmed by means of electronic circular dichroism (ECD) spectroscopy supported by theoretical calculations. Selected benzofuryl α-azole ketones were also successfully asymmetrically bioreduced by fungi of Saccharomyces cerevisiae and Aureobasidium pullulans species. Racemic and chiral β-amino alcohols, as well as benzofuryl α-amino and α-bromo ketones were evaluated for their antibacterial and antifungal activities. From among the synthesized β-amino alcohols, the highest antimicrobial activity was found for (R)-1-(3,5-dimethylbenzofuran-2-yl)-2-(1H-imidazol-1-yl)ethan-1-ol against S. aureus ATCC 25923 (MIC = 64, MBC = 96 μg mL−1) and (R)-1-(3,5-dimethylbenzofuran-2-yl)-2-(1H-1,2,4-triazol-1-yl)ethan-1-ol against yeasts of M. furfur DSM 6170 (MIC = MBC = 64 μg mL−1). In turn, from among the tested ketones, 1-(benzofuran-2-yl)-2-bromoethanones (1–4) were found to be the most active against M. furfur DSM 6170 (MIC = MBC = 1.5 μg mL−1) (MIC—minimal inhibitory concentration, MBC—minimal biocidal concentration).

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“…The absolute configuration of compound 1 was determined on the basis of its predicted optical rotation (OR). DFT prediction of OR is a valuable, although not as general, alternative to ECD for determining the absolute configuration of natural products, and can be reliably used for this purpose provided that (i) the magnitude of the measured OR is not close to zero and (ii) the sign of the calculated OR is the same for all, or at least for most conformers [28]. The OR of compound 1 was predicted at the B3LYP/TZVP/PCM(MeOH) level of theory; the calculated [α] D (as the Boltzmann average of individual conformers) was -104, compared to the experimental value -56.…”

Section: Structure Elucidationmentioning

confidence: 99%

Pyrenosetin D, a New Pentacyclic Decalinoyltetramic Acid Derivative from the Algicolous Fungus Pyrenochaetopsis sp. FVE-087

Fan

Dewapriya

et al. 2020

Marine Drugs

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The fungal genus Pyrenochaetopsis is commonly found in soil, terrestrial, and marine environments, however, has received little attention as a source of bioactive secondary metabolites so far. In a recent work, we reported the isolation and characterization of three new anticancer decalinoyltetramic acid derivatives, pyrenosetins A–C, from the Baltic Fucus vesiculosus-derived endophytic fungus Pyrenochaetopsis sp. FVE-001. Herein we report a new pentacyclic decalinoylspirotetramic acid derivative, pyrenosetin D (1), along with two known decalin derivatives wakodecalines A (2) and B (3) from another endophytic strain Pyrenochaetopsis FVE-087 isolated from the same seaweed and showed anticancer activity in initial screenings. The chemical structures of the purified compounds were elucidated by comprehensive analysis of HR-ESIMS, FT-IR, [α]D, 1D and 2D NMR data coupled with DFT calculations of NMR parameters and optical rotation. Compounds 1–3 were evaluated for their anticancer and toxic potentials against the human malignant melanoma cell line (A-375) and the non-cancerous keratinocyte cell line (HaCaT). Pyrenosetin D (1) showed toxicity towards both A-375 and HaCaT cells with IC50 values of 77.5 and 39.3 μM, respectively, while 2 and 3 were inactive. This is the third chemical study performed on the fungal genus Pyrenochaetopsis and the first report of a pentacyclic decalin ring system from the fungal genus Pyrenochaetopsis.

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Computational prediction of chiroptical properties in structure elucidation of natural products

Abstract: A tutorial review aimed to introduce natural product chemists to the predictions of natural product configurations by ECD and OR calculations.

Cited by 81 publications

References 106 publications

Furoic acid derivatives from the endophytic fungus Coniothyrium sp.

Furoic acid derivatives from the endophytic fungus Coniothyrium sp.

Synthesis, Absolute Configuration, Antibacterial, and Antifungal Activities of Novel Benzofuryl β-Amino Alcohols

Pyrenosetin D, a New Pentacyclic Decalinoyltetramic Acid Derivative from the Algicolous Fungus Pyrenochaetopsis sp. FVE-087

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