Hydrogen bonds in dimers of 3-hydroxy-2-methyl-4-pyrone. AIM analysis

Doronina, Evgeniya P.; Aksamentova, T. N.; Chípanina, N. N.; Mukha, Svetlana A.; Медведева, С. А.

doi:10.1134/s1070363209020224

Cited by 3 publications

(3 citation statements)

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“…Likewise, it advocates for the formation of hydrogen bonding with involvement of not only the O–C (ether) bond but also of the CO (ketone) bond. As reported elsewhere, the intramolecular hydrogen bond OH···OC is weak and has ionic nature in 3-hydroxy-2-methyl-4-pyrone (maltol) . For alkanol hydroxyl groups a hydrogen bond in its optimum geometry is only slightly stronger when formed to a ketone group than to an ether group .…”

Section: Discussionmentioning

confidence: 72%

“…As reported elsewhere, the intramolecular hydrogen bond OH•••OC is weak and has ionic nature in 3-hydroxy-2-methyl-4-pyrone (maltol). 48 For alkanol hydroxyl groups a hydrogen bond in its optimum geometry is only slightly stronger when formed to a ketone group than to an ether group. 49 Moreover, in the formation of hydrogen bonding lactones almost unchangeably bond to the carbonyl group rather than to the C−O−C group, presumably because of their relative proton donor powers.…”

Section: Energy and Fuelsmentioning

confidence: 99%

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FT-IR Analysis of Pyrone and Chromene Structures in Activated Carbon

et al. 2014

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The behavior of activated carbon in many catalysis processes is determined by the basic character of its surface. Using FT-IR spectroscopy, an attempt is made here to identify not only pyrone and chromene type structures but also their isomers in a commercial activated carbon (Merck; AC). The infrared analysis between 400 and 4000 cm −1 focuses on the keto (−CO) group in pyrones, methylene (−CH 2 −) group in chromenes, and enol ether group (O−CC) in both kinds of structures. Although overlapping bands are frequent in the AC spectrum, occurrence of most significant pyrone and chromene absorptions proves their presence in AC. This is so in particular for 2-pyrone and 4H-chromene, whereas 4-pyrone is less amenable to the infrared analysis.

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Section: Discussionmentioning

confidence: 72%

Section: Energy and Fuelsmentioning

confidence: 99%

FT-IR Analysis of Pyrone and Chromene Structures in Activated Carbon

et al. 2014

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“…In nonprotic solvents, the enolic −OH of the pyridinones would not provide hydrogen atom transfer to peroxyl radicals because hydrogen bonding to the adjacent carbonyl group is strong. For example, in maltol, it is approximately 7 kcal/mol 41 and the HAT reaction would require breaking of this bond simultaneously with breaking the O−H bond. The possibility of either the HAT or proton transfer coupled with electron transfer is very slight for the alternative diol structure (Figure 4) due to an unfavorable positive charge.…”

Section: ■ Discussionmentioning

confidence: 99%

Pyridinones Are Not Antioxidants As Shown by Kinetics of Free Radical Autoxidation, but They Prevent Radical Oxidations Catalyzed by Toxic Heavy Metals

Ramsaywack

Vogels

Ricker

et al. 2013

Chem. Res. Toxicol.

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Three 2-methyl-3-hydroxypyridinones, 1-methyl-, 1; 1-(4-methoxy)phenyl-, 2; and 1-(4-dimethylamino)phenyl-, 3, were discovered not to possess strong antioxidant properties contrary to literature reports. These pyridinones were not active chain-breaking antioxidants toward peroxyl radicals generated from styrene or methyl oleate initiated by azobis-2-methylpropylnitrile (AIBN) in solution compared to known phenolic antioxidants, 2,2,5,7,8-pentamethyl-6-hydroxychroman (PMHC) or 2,6-di-tert-butyl-4-methoxyphenyl (DBHA). Pyridinone 2 exhibited weak antioxidant activity in cumene, kinh = 1.3 × 10(3) M(-1) s(-1), compared to 2,6-di-tert-butyl-4-methylphenol (BHT), kinh = 4.3 × 10(3) M(-1) s(-1). The pyridinones were not active antioxidants during lipid peroxidation initiated by azobis-2-amidinopropane·2HCl (ABAP) in aqueous-lipid dispersions of 0.50 M sodium dodecyl sulfate (SDS) micelles where 2 did not inhibit peroxidation of methyl oleate at pH 7.0 or 4.0, while BHT exhibited effective suppression of oxygen uptake. In addition, 2 did not exhibit any cooperative antioxidant effect in combination with Trolox during inhibited peroxidation of linoleic acid in micelles. Pyridinones were effective preventative antioxidants in aqueous-lipid dispersions against reactions initiated by heavy metal ions, notably copper; for example, 2 blocked peroxidation of linoleic acid initiated by Cu ions in SDS micelles. In particular, both 2 and 3 were active in preventing the rapid pro-oxidation effects, "spikes", of very rapid oxygen uptake when phenolic antioxidants PMHC or Trolox were added to peroxidations initiated by Cu(2+). A proposal is given to account for such pro-oxidant effects.

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