Solution characterization of carboxybenzoquinone and the isolation of derived quinhydrones

Holmes, Timothy; John, V.; Vennerstrom, Jonathan L.; Choi, Keun-Young

doi:10.1021/jo00198a035

Cited by 17 publications

(11 citation statements)

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“…Previous work reported that gentisic acid can be chemically oxidized using common chemical oxidants leading to the formation of unstable compounds such as carboxybenzoquinone. , However, Holmes et al . reported that FeCl 3 failed to oxidize GA in aqueous solution.…”

Section: Resultsmentioning

confidence: 99%

Surface Complexation of 2,5-Dihydroxybenzoic Acid (Gentisic Acid) at the Nanosized Hematite−Water Interface: An ATR-FTIR Study and Modeling Approach

Hanna

Quilès

2011

Langmuir

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In this study, characteristic interactions of 2,5-dihydroxybenzoic acid (or gentisic acid, GA) with the surface of 15-nm-sized hematite (α-Fe2O3) were studied by combining batch macroscopic experiments, in situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopic investigations, and surface complexation modeling. A correlation between the pH, the amount of adsorbed GA, and the amount of Fe(III) released from the hematite surface was observed, whereas the dissolution of hematite nanoparticles became significant only at low pH and high ligand loading. From the ATR-FTIR results, two aqueous complex structures have been identified depending on pH. At the hematite-water interface, the occurrence of one deprotonated inner-sphere "bidentate" complex and one outer-sphere complex was suggested through all of the investigated pH range. At high surface coverage, variations of vibrational band intensities were observed, suggesting the occurrence of nonspecific molecular interactions. The macroscopic results (i.e., GA batch sorption and the ligand-promoted dissolution of hematite) obtained under a wide range of experimental conditions corroborated the ATR-FTIR microscopic findings. GA adsorption was described by a surface complexation model fitted to pH-adsorption curves with 1 mM sorbate concentration in the pH range of 3-9. Two surface complexes (one outer-sphere species (≡FeOH2)2···H2L((1+,1-)) and one inner-sphere species (≡Fe)2H2L) were proposed using the three-plane model. The inner-sphere complexes were predominant at low pH values, and the relative concentrations of the outer-sphere species increased with the pH increase. The formation of inner-sphere complexes at acidic pH values can promote the dissolution of nanosized hematite. At high solute loading, GA oxidation into carboxybenzoquinone compounds by ferric species was suspected, suggesting the occurrence of a redox reaction analogous to that of hydroquinone compounds.

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Section: Resultsmentioning

confidence: 99%

Surface Complexation of 2,5-Dihydroxybenzoic Acid (Gentisic Acid) at the Nanosized Hematite−Water Interface: An ATR-FTIR Study and Modeling Approach

Hanna

Quilès

2011

Langmuir

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“…This similar chemical property indicates that the oxidation of GA is accelerated by the addition of a combination of NaOCl�5H 2 O and NaOH. Regarding the oxidation reaction of GA, its conversion to the corresponding quinoid form, carboxybenzoquinone, has been reported [24,25]. Furthermore, the reaction has been shown to proceed further and form dark brown compounds, characterized as the quinhydrone complex containing carboxybenzoquinone, by any oxidant [24].…”

Section: Plos Onementioning

confidence: 99%

“…Regarding the oxidation reaction of GA, its conversion to the corresponding quinoid form, carboxybenzoquinone, has been reported [24,25]. Furthermore, the reaction has been shown to proceed further and form dark brown compounds, characterized as the quinhydrone complex containing carboxybenzoquinone, by any oxidant [24]. We conducted a spectral analysis using LC/TOF-MS to clarify the color reaction process of GA following the addition of NaOH and NaOCl�5H 2 O (Fig 5).…”

Section: Plos Onementioning

confidence: 99%

Novel absorbance peak of gentisic acid following the oxidation reaction

Hosokawa¹,

Shukuya²,

Sogabe³

et al. 2020

PLoS ONE

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Gentisic acid (GA), a metabolite of acetylsalicylic acid (ASA), and homogentisic acid (HGA), which is excreted at high levels in alkaptonuria, are divalent phenolic acids with very similar structures. Urine containing HGA is dark brown in color due to its oxidation. We recently reported a new oxidation method of HGA involving the addition of sodium hydroxide (NaOH) with sodium hypochlorite pentahydrate (NaOCl�5H 2 O), which is a strong oxidant. In the present study, we attempted to oxidize GA, which has a similar structure to HGA, using our method. We herein observed color changes in GA solution and analyzed the absorption spectra of GA after the addition of NaOH with NaOCl�5H 2 O. We also examined the oxidation reaction of GA using a liquid chromatography time-of-flight mass spectrometer (LC/TOF-MS). The results obtained indicated that GA solution had a unique absorption spectrum with a peak at approximately 500 nm through an oxidation reaction following the addition of NaOH with NaOCl�5H 2 O. This spectrophotometric method enables GA to be detected in sample solutions without expensive analytical instruments or a complex method.

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“…The in situ generation of quinone 24a was considered as an good choice due to its known instability. 18 Initial attempts using Ag 2 O 19 as the oxidant in toluene (r.t. or reflux) failed, giving rise to the degradation of 24 and recovery of unreacted diene 23. The use of MnO 2 , under the conditions reported by Brimble, 20 provided the expected cycloadduct, albeit in low yield (15%).…”

Section: Paper Syn Thesismentioning

confidence: 99%

Strategies towards the Synthesis of the Gilvocarcins

2016

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Two strategies for the synthesis of the gilvocarcins were explored in order to construct the C-arylglycosidic tricyclic core of these natural products. Whereas the addition of a complex naphthalene onto a carbohydrate-derived lactone, following Kishi's protocol failed, the key C-glycosidic bond was successfully forged in a regio-and stereoselective manner through the use of TMS-acetylide as the nucleophile. Conversion of the alkyne into a diene and Diels-Alder cycloaddition with an in situ generated quinone allowed the assembling of a tricyclic structure which could serve as an advance synthetic intermediate for the synthesis of the gilvocarcins.

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Solution characterization of carboxybenzoquinone and the isolation of derived quinhydrones

Cited by 17 publications

References 0 publications

Surface Complexation of 2,5-Dihydroxybenzoic Acid (Gentisic Acid) at the Nanosized Hematite−Water Interface: An ATR-FTIR Study and Modeling Approach

Surface Complexation of 2,5-Dihydroxybenzoic Acid (Gentisic Acid) at the Nanosized Hematite−Water Interface: An ATR-FTIR Study and Modeling Approach

Novel absorbance peak of gentisic acid following the oxidation reaction

Strategies towards the Synthesis of the Gilvocarcins

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