Carbon-13 nuclear magnetic resonance spectra of kojic acid and other 4-pyrone derivatives

Kingsbury, Charles A.; CLIFFTON, M. D.; Looker, J. H.

doi:10.1021/jo00878a033

Cited by 47 publications

(24 citation statements)

References 2 publications

(2 reference statements)

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“…C4 and C5 are strongly deshielded due to the resonance effect, mainly from C5, which is directly linked to the enolic hydroxyl. The chemicals shifts seen here are very similar to those found by Kingsbury et al 15 Figure 4 (A) shows a possible resonance model of KA before (A) and after (B) losing a proton.…”

Section: Nmrsupporting

confidence: 88%

“…The coordination modes of aluminum span the gamut of structural motifs from low three-coordinate (trigonal planar and T-shaped) and normal four-coordinate (tetrahedral) to high fivecoordinate (trigonal bipyramidal and square pyramidal) and sixcoordinate (octahedral) complexes. 15 Aluminium (III) complexes with pyromeconic acid, kojic acid and maltol were investigated because of their neurological properties. 16 The Al 3+ forms a series of highly stable Al 3+ L n 3-n complexes (n=1-3) with kojic acid 17 Even though some of the mentioned studies provided both spectrophotometric experiments and quantum mechanical calculations, a detailed correlation between quantum mechanical calculations and experimental data of KAH aluminum complexes is still uncovered.…”

Section: Introductionmentioning

confidence: 99%

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Elucidation of the electronic spectrum changes of KA-Al3+ complex by potentiometric titration, FTIR, 13C RMN and Quantum Mechanics

Piantavini¹,

Gonçalves²,

Trindade³

et al. 2017

Quim. Nova

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publicado na web em 31/05/2017Kojic acid (KA) is an organic acid widely used in pharmaceutical industry, mainly as a skin lightening agent. Based on the ability of KA to form complexes with ions, we found the most possible kind of complex formed with cation aluminum. KA-Al 3+ complex structures were studied using potentiometric and spectrophotometric (UV) titrations, FTIR and 13 C NMR. The electronic spectroscopy showed that the KA-Al 3+ complexes absorb at higher wavelengths (λ max = 305 nm) than do the non-complexed KA (λ max = 269 nm), confirming complexation. The IR spectra of KA complexed and not complexed allowed us to correlate the changes in the absorption of enol and carbonyl groups in absence and presence of Al 3+ in aqueous solutions. The complexation suggested by the potentiometric titration and FTIR spectroscopy are in accordance with the data obtained from NMR results. Calculations based on quantum mechanics were utilized to understand the differences found in the noncomplexed and complexed KAH electronic spectra

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Section: Nmrsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Elucidation of the electronic spectrum changes of KA-Al3+ complex by potentiometric titration, FTIR, 13C RMN and Quantum Mechanics

Piantavini¹,

Gonçalves²,

Trindade³

et al. 2017

Quim. Nova

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“…The carbons of these acetates are seenat 6 170.0 (s), 167.9 (s), 20.6 (q), and 20.4 (q), together with singlet carbons (6 157.1 (C-4), 155.6 (C-2), and 137.0 (C-3)), doublet carbons (6 130.5 (C-6) and 103.8 (C-5)), and a methylene carbon (6 61.3). The carbonyl carbon (C-4, 6 157.1) is coupled ( 3~C H = 8 HZ) to the C-6 hydrogen (6 7.06), in agreement with that reported (8). The isolation of hydroxymethylmaltol (1) is not surprising since the fungus was grown on a malt extract medium.…”

Section: -7supporting

confidence: 88%

The metabolites of Talaromycesflavus: Part 2. Biological activity and biosynthetic studies

Ayer¹,

Racok²

1990

Can. J. Chem.

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. Can. J. Chem. 68, 2095Chem. 68, (1990. The soil fungus Talaromycesjavus (Klocker) Stolk and Samson is an effective biological control for Verticillium wilt of eggplant (Solanurn melongena L.), a disease caused by the fungus Verticilliurn dahliae Kleb. The water soluble metabolites isolated from the broth when the fungus is grown in liquid still culture, hydroxymethylmaltol (I), 5,6-dihydro-3,5-dihydroxy-6-hydroxymethyl-2H-pyran-2-one (3), and D-glucono-l,4-lactone (5), do not show antifungal activity against V. dahliae; however, hydrogen peroxide displays this inhibition. This peroxide has been detected in the T.javus broth and it, together with 5, is the product of the glucose oxidase catalyzed oxidation of D-glucose. The results of the search for this antifungal activity are presented. [l-13C] Labelled sodium acetate was utilized as a precursor for studying the biosynthesis of the T. javus metabolites 4,6-dihydroxy-5-methylphthalide (7), methyl 4-carboxy-5-hydroxyphthalaldehydate (a), and talaroflavone (9). The incorporation of label into these compounds is discussed.

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“…12 and references in Table 2). Similarly, the a-carbon resonances (158.5 and 160.2 ppm) and the P-carbon resonances (97.0 and 105.9 ppm) are typical of y-pyrones (P-range normally 88-120 ppm; a-range normally 139-1 67 pprn (ref.…”

Section: Discussionmentioning

confidence: 99%

Pyrones. IV. Phacidin, a fungal growth inhibitor from Potebniamycesbalsamicola Smerlis var. boycei Funk

Arthur¹,

Cyr²,

McMullan³

1979

Can. J. Chem.

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Carbon-13 nuclear magnetic resonance spectra of kojic acid and other 4-pyrone derivatives

Cited by 47 publications

References 2 publications

Elucidation of the electronic spectrum changes of KA-Al3+ complex by potentiometric titration, FTIR, 13C RMN and Quantum Mechanics

Elucidation of the electronic spectrum changes of KA-Al3+ complex by potentiometric titration, FTIR, 13C RMN and Quantum Mechanics

The metabolites of Talaromycesflavus: Part 2. Biological activity and biosynthetic studies

Pyrones. IV. Phacidin, a fungal growth inhibitor from Potebniamycesbalsamicola Smerlis var. boycei Funk

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