Aromaticity and Electron Density of Hypericin

Szymański, Sebastian; Majerz, Irena

doi:10.1021/acs.jnatprod.8b00872

Cited by 7 publications

(7 citation statements)

References 72 publications

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“…Such a close position of the substituents allows the formation of a hydrogen bond system in which hydroxyl groups are directed to the centrally located carbonyl oxygen. As shown for the hypericin molecule [13], such formation of strong hydrogen bonds is energetically preferred, and these hydrogen bonds are difficult to break. What is new in the structure of fagopyrin is Conformers representing different arrangements and interactions of substituent hydroxyl groups, carbonyl oxygen, piperidine, and pyrrolidine rings were compiled based on a structure with minimum energy.…”

Section: Conformational Analysis Of Fagopyrinsmentioning

confidence: 99%

“…The structure and intramolecular interactions of polycyclic compounds affect the physical and chemical properties and can influence potential applications of the compounds in pharmacy and medicine [9][10][11][12]. As shown in earlier work on hypericin [13] and sennidines [14], a highly substituted polycyclic system can exhibit a non-planar structure due to a variety of intramolecular interactions. At the time of writing this paper, data unambiguously define the spatial and electronic structures of fagopyrins.…”

Section: Introductionmentioning

confidence: 95%

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Theoretical Studies on the Structure and Intramolecular Interactions of Fagopyrins—Natural Photosensitizers of Fagopyrum

Szymański

Majerz

2022

Molecules

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Compounds characterized by a double-anthrone moiety are found in many plant species. One of them are fagopyrins—naturally occurring photosensitizers of Fagopyrum. The photosensitizing properties of fagopyrins are related to the selective absorption of light, which is a direct result of their spatial and electronic structure and many intramolecular interactions. The nature of the interactions varies in different parts of the molecule. The aim of this study is to determine the structure and intramolecular interactions of fagopyrin molecules. For this purpose, in silico calculations were used to perform geometry optimization in the gas phase. QTAIM and NCI analysis suggest the formation of the possible conformers in the fagopyrin molecules. The presence of a strong OHO hydrogen bond was shown in the anthrone moiety of fagopyrin. The minimum energy difference for selected conformers of fagopyrins was 1.1 kcal∙mol−1, which suggested that the fagopyrin structure may exist in a different conformation in plant material. Similar interactions were observed in previously studied structures of hypericin and sennidin; however, only fagopyrin showed the possibility of brake the strong OHO hydrogen bond in favor of forming a new OHN hydrogen bond.

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Section: Conformational Analysis Of Fagopyrinsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

Theoretical Studies on the Structure and Intramolecular Interactions of Fagopyrins—Natural Photosensitizers of Fagopyrum

Szymański

Majerz

2022

Molecules

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“…This is one of the best methods to describe the change in aromaticity [23]. If HOMA is unity [22], it means the compound is fully aromatic, while if HOMA equals zero (0), the compound or ring is completely non-aromatic.…”

Section: Aromaticity Indicesmentioning

confidence: 99%

“…Aromaticity of organic compounds is one of the most important characteristics related to the specific chemical reactivity structure [22]. As a measure of aromaticity, many parameters based structural changes or electron densities can be used [23].…”

Section: Introductionmentioning

confidence: 99%

Aromaticity indices, electronic structural properties, and fuzzy atomic space investigations of naphthalene and its aza-derivatives

Edim

Enudi

Asuquo

et al. 2021

Heliyon

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“…The structure of sennidin is characterized by a number of substituents. Substitution allows for the formation of strong OHO hydrogen bonding [1]. The sennidin structure is characterized by the rotation of the anthron moieties.…”

Section: Introductionmentioning

confidence: 99%

In Silico Studies on Sennidines—Natural Dianthrones from Senna

Szymański

Majerz

2021

Biology

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The rapid development of technology allows for more accurate research of biological systems with the use of in silico methods. One of the tools is the quantum-chemical method used for determining the structure, properties and interactions of molecules of great pharmacological importance. The accuracy of theoretical models is increasing and can be a real help in biology, chemistry and pharmacy. The aim of the study is to determine the spatial structure and intramolecular interactions of sennidines—natural pharmaceutical substances present in Senna species. Calculations carried out in the gas-phase and in the solvent model, compared with the available experimental data indicate the possibility of sennidines to form conformers. QTAIM and NCI analysis suggests the presence of many intramolecular interactions in the sennidin structure. Taking into account the lowest energy optimized structure, it can be predicted that the sennidin in the gauche conformation will be present in the plant material. The single C-C bond connecting the anthrone moieties is elongated and its reduced Bond Dissociation Energy (BDE) could be the cause of an easy breakdown of the sennidin molecule into monoanthrones. This work contains data on theoretical, vibrational and electron excitation spectra, which can be used in the analysis of experimental samples.

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Aromaticity and Electron Density of Hypericin

Cited by 7 publications

References 72 publications

Theoretical Studies on the Structure and Intramolecular Interactions of Fagopyrins—Natural Photosensitizers of Fagopyrum

Theoretical Studies on the Structure and Intramolecular Interactions of Fagopyrins—Natural Photosensitizers of Fagopyrum

Aromaticity indices, electronic structural properties, and fuzzy atomic space investigations of naphthalene and its aza-derivatives

In Silico Studies on Sennidines—Natural Dianthrones from Senna

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