Quinone dehydrogenation. Oxidation of benzylic alcohols with 2,3-dichloro-5,6-dicyanobenzoquinone

Becker, Hans Dieter; Bjoerk, Anders; Adler, Erich

doi:10.1021/jo01297a010

Cited by 104 publications

(34 citation statements)

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“…Therefore, such substituents greatly raise the reaction rate, while electron-withdrawing substituents render the oxidation more difficult. 54) In fact, LCC model compounds of 3-methoxy-4-hydroxy (I) and 3-methoxy-4-benzyloxy benzyl ether compounds (IV) were oxidatively decomposed by DDQ, while a p-acetoxy LCC model compound (II) was inert to the oxidation prQcess (Table III). As could be expected from the inductive effect of p-substituents, the reaction rate.…”

Section: Discussionmentioning

confidence: 99%

Binding-site Analysis of the Ether Linkages between Lignin and Hemicelluloses in Lignin–Carbohydrate Complexes by DDQ-Oxidation

Watanabe¹,

Ohnishi²,

Yamasaki³

et al. 1989

Agricultural and Biological Chemistry

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Section: Discussionmentioning

confidence: 99%

Binding-site Analysis of the Ether Linkages between Lignin and Hemicelluloses in Lignin–Carbohydrate Complexes by DDQ-Oxidation

Watanabe¹,

Ohnishi²,

Yamasaki³

et al. 1989

Agricultural and Biological Chemistry

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“…Chemical Preparation and Aldehyde/Alcohol Synthesis p-Coumaryl alcohol was prepared from ethyl p-coumarate according to published methods (Quideau and Ralph, 1992), and p-coumaraldehyde was prepared from p-coumaryl alcohol by 2,3-dichloro-5,6-dicyanobenzoquinone oxidation as described previously (Becker et al, 1980). p-Coumaric acid, sinapic acid, caffeic acid, and the corresponding alcohols and aldehydes (except p-coumaraldehyde and p-coumaryl alcohol) and 2-methoxybenzaldehyde/2-methoxybenzyl alcohol were purchased from Sigma-Aldrich.…”

Section: Plant Growth and Treatmentmentioning

confidence: 99%

Molecular and Biochemical Basis for Stress-Induced Accumulation of Free and Boundp-Coumaraldehyde in Cucumber

Varbanova

Porter

et al. 2011

Plant Physiology

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To elucidate the genetic and biochemical regulation of elicitor-induced p-coumaraldehyde accumulation in plants, we undertook a multifaceted approach to characterize the metabolic flux through the phenylpropanoid pathway via the characterization and chemical analysis of the metabolites in the p-coumaryl, coniferyl, and sinapyl alcohol branches of this pathway. Here, we report the identification and characterization of four cinnamyl alcohol dehydrogenases (CADs) from cucumber (Cucumis sativus) with low activity toward p-coumaraldehyde yet exhibiting significant activity toward other phenylpropanoid hydroxycinnamaldehydes. As part of this analysis, we identified and characterized the activity of a hydroxycinnamoyl-coenzyme A:shikimate hydroxycinnamoyl transferase (HCT) capable of utilizing shikimate and p-coumaroyl-coenzyme A to generate p-coumaroyl shikimate. Following pectinase treatment of cucumber, we observed the rapid accumulation of p-coumaraldehyde, likely the result of low aldehyde reductase activity (i.e. alcohol dehydrogenase in the reverse reaction) of CsCAD enzymes on p-coumaraldehyde. In parallel, we noted a concomitant reduction in the activity of CsHCT. Taken together, our findings support the hypothesis that the up-regulation of the phenylpropanoid pathway upon abiotic stress greatly enhances the overall p-coumaryl alcohol branch of the pathway. The data presented here point to a role for CsHCT (as well as, presumably, p-coumarate 3-hydroxylase) as a control point in the regulation of the coniferyl and sinapyl alcohol branches of this pathway. This mechanism represents a potentially evolutionarily conserved process to efficiently and quickly respond to biotic and abiotic stresses in cucurbit plants, resulting in the rapid lignification of affected tissues.

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“…For its synthesis, compound 2 (70 mg, 0.21 mmol) was dissolved in tetrahydrofuran (10 mL) and 2,3-dichloro-5,6-dicyanobenzoquinone (Becker et al, 1980) was added. The reaction mixture was stirred overnight at room temperature.…”

Section: Chemical Synthesis Of Dilignols Trilignols and Tetralignolsmentioning

confidence: 99%

Profiling of Oligolignols Reveals Monolignol Coupling Conditions in Lignifying Poplar Xylem

et al. 2004

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Lignin is an aromatic heteropolymer, abundantly present in the walls of secondary thickened cells. Although much research has been devoted to the structure and composition of the polymer to obtain insight into lignin polymerization, the lowmolecular weight oligolignol fraction has escaped a detailed characterization. This fraction, in contrast to the rather inaccessible polymer, is a simple and accessible model that reveals details about the coupling of monolignols, an issue that has raised considerable controversy over the past years. We have profiled the methanol-soluble oligolignol fraction of poplar (Populus spp.) xylem, a tissue with extensive lignification. Using liquid chromatography-mass spectrometry, chemical synthesis, and nuclear magnetic resonance, we have elucidated the structures of 38 compounds, most of which were dimers, trimers, and tetramers derived from coniferyl alcohol, sinapyl alcohol, their aldehyde analogs, or vanillin. All structures support the recently challenged random chemical coupling hypothesis for lignin polymerization. Importantly, the structures of two oligomers, each containing a g-p-hydroxybenzoylated syringyl unit, strongly suggest that sinapyl p-hydroxybenzoate is an authentic precursor for lignin polymerization in poplar.

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Quinone dehydrogenation. Oxidation of benzylic alcohols with 2,3-dichloro-5,6-dicyanobenzoquinone

Cited by 104 publications

References 0 publications

Binding-site Analysis of the Ether Linkages between Lignin and Hemicelluloses in Lignin–Carbohydrate Complexes by DDQ-Oxidation

Binding-site Analysis of the Ether Linkages between Lignin and Hemicelluloses in Lignin–Carbohydrate Complexes by DDQ-Oxidation

Molecular and Biochemical Basis for Stress-Induced Accumulation of Free and Boundp-Coumaraldehyde in Cucumber

Profiling of Oligolignols Reveals Monolignol Coupling Conditions in Lignifying Poplar Xylem

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