Preparation and reactivity of 2,6—dimethoxy—4—allylidene—2,5—cyclohexadien—1—one (vinyl quinone methide) a novel synthesis of sinapyl alcohol

Zanarotti, A.

doi:10.1016/s0040-4039(00)87715-1

Cited by 29 publications

(12 citation statements)

References 5 publications

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“…Zanarotti (1982) originally showed that phenolics with a benzylic-CH 2 group could form the quinone methides, via radical disproportionation as shown in Supplemental Figure 10 (Ralph et al, 2009). In the case of 8-5-coupled products, the quinone methide formed is exactly the same intermediate moiety as produced by oxidative coupling of a monolignol (at its 8-position) with a phenolic guaiacyl unit, i.e., the same as that produced during lignification.…”

Section: Pcber Protects Xylem Cells Against Lignification-induced Oximentioning

confidence: 99%

Phenylcoumaran Benzylic Ether Reductase Prevents Accumulation of Compounds Formed under Oxidative Conditions in Poplar Xylem

et al. 2014

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Phenylcoumaran benzylic ether reductase (PCBER) is one of the most abundant proteins in poplar (Populus spp) xylem, but its biological role has remained obscure. In this work, metabolite profiling of transgenic poplar trees downregulated in PCBER revealed both the in vivo substrate and product of PCBER. Based on mass spectrometry and NMR data, the substrate was identified as a hexosylated 8-5-coupling product between sinapyl alcohol and guaiacylglycerol, and the product was identified as its benzyl-reduced form. This activity was confirmed in vitro using a purified recombinant PCBER expressed in Escherichia coli. Assays performed on 20 synthetic substrate analogs revealed the enzyme specificity. In addition, the xylem of PCBER-downregulated trees accumulated over 2000-fold higher levels of cysteine adducts of monolignol dimers. These compounds could be generated in vitro by simple oxidative coupling assays involving monolignols and cysteine. Altogether, our data suggest that the function of PCBER is to reduce phenylpropanoid dimers in planta to form antioxidants that protect the plant against oxidative damage. In addition to describing the catalytic activity of one of the most abundant enzymes in wood, we provide experimental evidence for the antioxidant role of a phenylpropanoid coupling product in planta.

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Section: Pcber Protects Xylem Cells Against Lignification-induced Oximentioning

confidence: 99%

Phenylcoumaran Benzylic Ether Reductase Prevents Accumulation of Compounds Formed under Oxidative Conditions in Poplar Xylem

et al. 2014

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“…C3,H2,01, requires M , 604.1581); 'H n.m.r. data in Table 1; m/z 604 ( M + , 48%), 562 (loo), 520 (29), 502 (28), 460 (59), 384 (1 l), 342 (lo), 300 (24), 270 (1 l), 260 (14), 230 (14), 222 (97), 180 (21), 179 (31), 162 (31), 151 (13), 148 (13), 147 (16), and 137 (13).…”

Section: '4-di-o-methylxunthocercin a @mentioning

confidence: 99%

Oligomeric isoflavonoids. Part 2. Structure and synthesis of xanthocercin A and B, the first isoflavono-lignoids

Bezuidenhout¹,

Bezuidenhoudt²,

Brandt³

et al. 1988

J. Chem. Soc., Perkin Trans. 1

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The structures of xanthocercin A and B, the first isoflavono-lignoids, have been established as 2,3-trans-(3) respectively by spectroscopic methods. These structures have been confirmed by synthesis via phenol oxidative coupling of the appropriate 7,8-dihydroxyisoflavone and respectively sinapyl and coniferyl alcohol. The natural occurrence of xanthocercin A and B as single regioisomers and their regiospecific formation during synthesis presumably originate from marked differences in susceptibility to oxidation of the hydroxy functions in their 'catechol precursors'.

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“…The mechanism, via a vinylogous quinone methide 4 , involves two H-radical abstractions. Abstraction from a benzylic CH 2 to produce quinone methides from phenoxy radicals has been noted previously . When DHCA is subjected to peroxidase−H 2 O 2 , monomeric APD 1 as well as the range of homo dimers and crossed dimers 7 − 11 (Scheme ) involving DHCA and APD are found, as will be detailed elsewhere.…”

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confidence: 57%

Arylpropane-1,3-diols in Lignins from Normal and CAD-Deficient Pines

et al. 1999

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Significant quantities of arylopropane-1,3-diols have been identified in lignins isolated from a CAD-deficient pine mutant; smaller amounts are also present in lignins from normal pine. They arise from dihydroconiferyl alcohol via the action of peroxidases which are responsible for the radical generation steps of lignification. The structures in the complex lignin polymers are proven using 2D and 3D NMR of isolated lignin fractions.

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Preparation and reactivity of 2,6—dimethoxy—4—allylidene—2,5—cyclohexadien—1—one (vinyl quinone methide) a novel synthesis of sinapyl alcohol

Cited by 29 publications

References 5 publications

Phenylcoumaran Benzylic Ether Reductase Prevents Accumulation of Compounds Formed under Oxidative Conditions in Poplar Xylem

Phenylcoumaran Benzylic Ether Reductase Prevents Accumulation of Compounds Formed under Oxidative Conditions in Poplar Xylem

Oligomeric isoflavonoids. Part 2. Structure and synthesis of xanthocercin A and B, the first isoflavono-lignoids

Arylpropane-1,3-diols in Lignins from Normal and CAD-Deficient Pines

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