Demethylation and tannin-like properties of guaiacyl/syringyl-type and syringyl-type dehydrogenation polymers using iodocyclohexane

The demethylation of guaiacyl/syringyl (G/S)-type (G/S = 1/1) and syringyl (S)-type dehydrogenation polymers (DHPs) using iodocyclohexane (ICH) under reflux in DMF was performed to afford demethylated G/S- and S-DHPs in moderate yields. Along with significant structural changes, such as side-chain c...

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Bibliographic Details
Published in:Journal of wood science 2022-12, Vol.68 (1), p.51-7, Article 51
Main Authors: Kobayashi, Tokimitsu, Tobimatsu, Yuki, Kamitakahara, Hiroshi, Takano, Toshiyuki
Format: Article
Language:English
Subjects:
Adsorbents
Adsorption
Biomedical and Life Sciences
Characterization and Evaluation of Materials
Coherence
Dehydrogenation
Demethylation
DHP
Free radicals
Hardwood
Life Sciences
Lignin
Materials Science
NMR
Nuclear magnetic resonance
Original Article
Oxidizing agents
Phenols
Polymers
Quantum phenomena
Scavenging
Serum albumin
Softwoods
Tannin
Tannins
Wood Science & Technology
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Summary:The demethylation of guaiacyl/syringyl (G/S)-type (G/S = 1/1) and syringyl (S)-type dehydrogenation polymers (DHPs) using iodocyclohexane (ICH) under reflux in DMF was performed to afford demethylated G/S- and S-DHPs in moderate yields. Along with significant structural changes, such as side-chain cleavage and recondensation, as observed using heteronuclear single quantum coherence (HSQC) NMR spectra, the phenolic-OH content of the demethylated DHPs increased, as expected. The tannin-like properties, such as the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging ability, iron(III) binding ability, and bovine serum albumin (BSA) adsorption ability, of the demethylated DHPs increased with increasing reaction time. In particular, the BSA adsorption ability was significantly enhanced by demethylation of the G/S- and S-DHPs, and was better than that of G-DHP reported previously. These results indicate that hardwood lignin containing both G and S units is more suitable than softwood lignin containing only G units for functionalization through demethylation into a tannin-like polymer, which has applications as a natural oxidant, metal adsorbent, and protein adsorbent.
ISSN:1435-0211
1611-4663
DOI:10.1186/s10086-022-02059-w