Intra- and intermolecular hydrogen bonding in 3-hydroxy- and 5-hydroxychromone

Binbuga, Nursen; Schultz, Tor P.; Henry, William P.

doi:10.1016/j.tetlet.2008.07.100

Cited by 14 publications

(6 citation statements)

References 36 publications

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“…Hence the concomitant presence of flavonoid molecules and tosyl groups in the S2 region (Figure C, D) has to be based on other types of interactions. Previous studies on the crystal structure of 3-HF demonstrated the presence of intramolecular H-bonding between the hydroxyl group and the ketone, and intermolecular interactions including stacking of conjugated aromatic rings, and H-bonding in between neighboring stacks. , Given the ability of 3-HF to enter the cell wall, and to form intra- and intermolecular associations via weak hydrogen bonding and π-stacking, the occurrence of such interactions with lignin polymers and tosylated cell wall polymers in the treated spruce samples is highly probable.…”

Section: Resultsmentioning

confidence: 97%

“…Previous studies on the crystal structure of 3-HF demonstrated the presence of intramolecular H-bonding between the hydroxyl group and the ketone, and intermolecular interactions including stacking of conjugated aromatic rings, and H-bonding in between neighboring stacks. 27,28 Given the ability of 3-HF to enter the cell wall, and to form intra-and intermolecular associations via weak hydrogen bonding and π-stacking, the occurrence of such interactions with lignin polymers and tosylated cell wall polymers in the treated spruce samples is highly probable. Evidence of π-stacking can be found in Raman spectra frequency shifts of the aromatic systems which were observed in the modified cell wall (Figure 6A).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Flavonoid Insertion into Cell Walls Improves Wood Properties

Ermeydan

Cabane

Mašić

et al. 2012

ACS Appl. Mater. Interfaces

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Wood has an excellent mechanical performance, but wider utilization of this renewable resource as an engineering material is limited by unfavorable properties such as low dimensional stability upon moisture changes and a low durability. However, some wood species are known to produce a wood of higher quality by inserting mainly phenolic substances in the already formed cell walls--a process so-called heartwood formation. In the present study, we used the heartwood formation in black locust (Robinia pseudoacacia) as a source of bioinspiration and transferred principles of the modification in order to improve spruce wood properties (Picea abies) by a chemical treatment with commercially available flavonoids. We were able to effectively insert hydrophobic flavonoids in the cell wall after a tosylation treatment for activation. The chemical treatment reduced the water uptake of the wood cell walls and increased the dimensional stability of the bulk spruce wood. Further analysis of the chemical interaction of the flavonoid with the structural cell wall components revealed the basic principle of this bioinspired modification. Contrary to established modification treatments, which mainly address the hydroxyl groups of the carbohydrates with hydrophilic substances, the hydrophobic flavonoids are effective by a physical bulking in the cell wall most probably stabilized by π-π interactions. A biomimetic transfer of the underlying principle may lead to alternative cell wall modification procedures and improve the performance of wood as an engineering material.

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Section: Resultsmentioning

confidence: 97%

Section: ■ Results and Discussionmentioning

confidence: 99%

Flavonoid Insertion into Cell Walls Improves Wood Properties

Ermeydan

Cabane

Mašić

et al. 2012

ACS Appl. Mater. Interfaces

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“…Similar findings have been reported for different types of systems. [7,8] In contrast, compound 1 present in the same region has only two signals: one corresponding to the CONH function This preliminary study points out that the presence of a hydrogen-bond network in chromone compounds is crucial for MAO-B selectivity. The intramolecular resonance-assisted hydrogen bond (RAHB) present in chromone-3-carboxamide (2) allows the stabilization of a folded state with the formation of a six-membered, hydrogen-bonded pseudocycle that appears to be important for biological activity.…”

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confidence: 84%

Towards the Discovery of a Novel Class of Monoamine Oxidase Inhibitors: Structure–Property–Activity and Docking Studies on Chromone Amides

et al. 2011

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“…69 Also, ring B is considered as conjugated with the 3-OH group in flavone. 70 Trouillas and coworkers 71,72 conjugation over the entire molecule (e.g., galangin, quercetin); removal of 3-OH (as in chrysin or luteolin) leads to partial loss of π conjugation, while lack of the C2−C3 double bond (as in taxifolin) interrupts the conjugation path. The extended electron delocalization in hydroxyflavones has also been highlighted by many other authors.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Introduction of the 3-OH group to form 3-hydroxyflavone causes increased aromaticity of the pyrone ring . Also, ring B is considered as conjugated with the 3-OH group in flavone . Trouillas and co-workers , demonstrated that hydroxyflavones with a C4 keto group, 3-OH group and C2–C3 double bond do exhibit π conjugation over the entire molecule (e.g., galangin, quercetin); removal of 3-OH (as in chrysin or luteolin) leads to partial loss of π conjugation, while lack of the C2–C3 double bond (as in taxifolin) interrupts the conjugation path.…”

Section: Results and Discussionmentioning

confidence: 99%

Media Effects on the Mechanism of Antioxidant Action of Silybin and 2,3-Dehydrosilybin: Role of the Enol Group

2013

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Silybin (SIL) and 2,3-dehydrosilybin (DHS) are constituents of milk thistle extract (silymarin) applied in the treatment of cirrhosis, hepatitis, and alcohol-induced liver disease. The molecular mechanism of their action is usually connected with antioxidant action. However, despite experimental and theoretical evidence for the antioxidant activity of SIL and DHS, the mechanism of their antiradical action still remains unclear. We studied the kinetics of SIL/DHS reactions with 2,2-diphenyl-1-picrylhydrazyl radical in organic solutions of different polarity and with peroxyl radicals in a micellar system mimicking the amphiphilic environment of lipid membranes. Kinetic studies together with determination of acidity and electrochemical measurements allowed us to discuss the structure-activity relationship in detail. In nonpolar solvents the reaction with free radicals proceeds via a one-step hydrogen atom transfer (HAT) mechanism, while significant acceleration of the reaction rates in methanol and water/methanol solutions suggests the dominating contribution of a sequential proton-loss electron-transfer (SPLET) mechanism with participation of the most acidic hydroxyl groups: 7-OH in SIL and 7-OH and 3-OH in DHS. In a heterogeneous water/lipid system, both mechanisms operate; however, the reaction kinetics and the antioxidant efficacy depend on the partition between lipid and water phases.

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Intra- and intermolecular hydrogen bonding in 3-hydroxy- and 5-hydroxychromone

Cited by 14 publications

References 36 publications

Flavonoid Insertion into Cell Walls Improves Wood Properties

Flavonoid Insertion into Cell Walls Improves Wood Properties

Towards the Discovery of a Novel Class of Monoamine Oxidase Inhibitors: Structure–Property–Activity and Docking Studies on Chromone Amides

Media Effects on the Mechanism of Antioxidant Action of Silybin and 2,3-Dehydrosilybin: Role of the Enol Group

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