Stereo-Preference in the Degradation of theErythroandThreoIsomers ofβ‐O‐4‐Type Lignin Model Compounds in Oxidation Processes: Part 1: In the Reaction with Active Oxygen Species Under Oxygen Delignification Conditions

Posoknistakul, Pattaraporn; Akiyama, Takuya; Yokoyama, Tomoya; Matsumoto, Yuji

doi:10.1080/02773813.2016.1138133

Cited by 14 publications

(24 citation statements)

References 29 publications

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“…The synthesis of compound 1 and separation of the E and T isomers were described in our previous studies [29,30]. The 1 H-and 13 C-NMR spectral data of compound 1 were reported in our previous study [29].…”

Section: Methodsmentioning

confidence: 99%

“…All chemicals except compound 1 were commercially available and used without further purification [29,30]. The synthesis of compound 1 and separation of the E and T isomers were described in our previous studies [29,30].…”

Section: Methodsmentioning

confidence: 99%

“…The detailed work-up procedures for quantification were described in our previous studies [29,30]. Quantification was on the basis of a calibration line prepared for compound 1 or each degradation product with an internal standard compound, 4-chlorophenol.…”

Section: Quantification Of Degradation Productsmentioning

confidence: 99%

“…1), was used as the generator of 10 min, reaction period: 360 min, volume of solution: 300 mL. The detailed procedures were described in our previous study [29].…”

Section: Alkaline Oxygen Treatment Simulating An Oxygen Delignificatimentioning

confidence: 99%

“…1), was individually treated with alkaline oxygen or hydrogen peroxide to examine the E or T stereo-preference of active oxygen species (AOS) generated in the system under conditions simulating a practical pulp bleaching process [29,30]. This study reports that 3,4-dimethoxybenzaldehyde (veratraldehyde, Fig.…”

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confidence: 99%

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Predominant formation of aromatic aldehyde and acid from a dimeric β-O-4-type lignin model compound under hydrogen peroxide bleaching conditions with high pH levels

et al. 2017

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Quantification Of Degradation Productsmentioning

confidence: 99%

“…1), was used as the generator of 10 min, reaction period: 360 min, volume of solution: 300 mL. The detailed procedures were described in our previous study [29].…”

Section: Alkaline Oxygen Treatment Simulating An Oxygen Delignificatimentioning

confidence: 99%

mentioning

confidence: 99%

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Predominant formation of aromatic aldehyde and acid from a dimeric β-O-4-type lignin model compound under hydrogen peroxide bleaching conditions with high pH levels

et al. 2017

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Stereo-preference in the degradation of the erythro and threo isomers of β-O-4-type lignin model compounds in oxidation processes III: in the reaction with chlorine- and manganese-based oxidants

et al. 2018

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We examined which isomer, the erythro or threo, of a non-phenolic β-O-4-type lignin model compound is stereo-preferentially oxidized in hypochlorite, chlorite, manganese dioxide, or permanganate systems. No clear stereo-preference was observed in the hypochlorite or chlorite systems at alkaline, neutral, or acidic pH except for a slight threo stereo-preference that appeared after the step-wise addition of the oxidizing reagent had been terminated in the neutral or acidic chlorite systems. A clear threo stereo-preference was observed in the manganese dioxide or permanganate systems.

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Lignin-Biosynthetic Study: Reactivity of Quinone Methides in the Diastereopreferential Formation of p-Hydroxyphenyl- and Guaiacyl-Type β-O-4 Structures

Zhu

Akiyama

Yokoyama

et al. 2019

J. Agric. Food Chem.

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p-Quinone methides are involved in lignin biosynthesis as transient intermediates, and the aromatization step has a great impact on the chemical structure of the resulting lignin. A series of quinone methides (QMs) were synthesized and allowed to react with water in pH 3–7 buffers at 25 °C to mimic the formation of p-hydroxyphenyl- and guaiacyl-type (H- and G-type, respectively) β-O-4 structures in gymnosperm-plant cell walls. Water addition occurred in 3-methoxy-substituted QMs (G-type QMs) with half-lives of 1.4–15 min. In contrast, nonsubstituted QMs (H-type QMs) were very labile; they were aromatized to β-O-4 products with half-lives of only 10–40 s. The rapid aromatization in H-type QMs may provide an advantage over G-type species for efficiently driving the lignin-polymerization cycle, which possibly contributes to the development of highly lignified compression wood. In the water-addition reaction, the threo isomers of the β-O-4 products were stereopreferentially formed more than the erythro isomers from both G- and H-type QMs (erythro/threo ratios of 24:76 and 50:50, respectively). The proportion of erythro isomers was higher at lower-pH conditions. This pH-dependent trend agrees with findings from a previous study on 3,5-dimethoxy-substituted (syringyl-type, S-type) QMs; thus, this pH-dependent trend is common in H-, G-, and S-type lignin-related QMs. Higher threo-selectivity was obtained by changing the β-etherified aromatic rings from G- to H-type. A similar but weaker effect was also observed by changing the QM moiety from G- to H-type.

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Stereo-Preference in the Degradation of theErythroandThreoIsomers ofβ‐O‐4‐Type Lignin Model Compounds in Oxidation Processes: Part 1: In the Reaction with Active Oxygen Species Under Oxygen Delignification Conditions

Cited by 14 publications

References 29 publications

Predominant formation of aromatic aldehyde and acid from a dimeric β-O-4-type lignin model compound under hydrogen peroxide bleaching conditions with high pH levels

Predominant formation of aromatic aldehyde and acid from a dimeric β-O-4-type lignin model compound under hydrogen peroxide bleaching conditions with high pH levels

Stereo-preference in the degradation of the erythro and threo isomers of β-O-4-type lignin model compounds in oxidation processes III: in the reaction with chlorine- and manganese-based oxidants

Lignin-Biosynthetic Study: Reactivity of Quinone Methides in the Diastereopreferential Formation of p-Hydroxyphenyl- and Guaiacyl-Type β-O-4 Structures

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