Category: 183303-74-4

Astolfi, Paola published the artcileNew mediators for the enzyme laccase: mechanistic features and selectivity in the oxidation of non-phenolic substrates, Synthetic Route of 183303-74-4, the publication is New Journal of Chemistry (2005), 29(10), 1308-1317, database is CAplus.

New mediators of laccase have been comparatively evaluated and ranked towards the benchmark aerobic oxidation of p-MeO-benzyl alc. The mechanism of oxidation of this non-phenolic substrate by each mediator, which is initially oxidized by laccase to the Med_ox form, has been assessed among three alternatives. The latter make the phenoloxidase laccase competent for the indirect oxidation of non-phenolic (and thus unnatural) substrates. Exptl. characterization of the mediators, by spectrophotometric, electrochem. and thermochem. survey, is reported. Clear-cut evidence for the formation of a benzyl radical intermediate in the oxidation of a particular benzyl alc. with laccase and a :N-OH mediator is attained by a trapping experiment The selectivity of the laccase-catalyzed oxidation of two competing lignin and polysaccharide model compounds has been assessed by using the highly proficient 4-MeO-HPI mediator, and found very high in favor of the former model. This evidence is in keeping with the operation of a radical hydrogen-abstraction process that efficiently cleaves the benzylic rather than the aliphatic C-H bond of the two models. Significant is the finding that catechol, i.e., a model of recurring phenolic structures in lignin, once oxidized to aryloxyl radical by laccase is capable to mediate a radical oxidation of non-phenolic compounds This supports a fully-fledged role of laccase as a delignifying enzyme in nature by way of no other mediators than the very phenolic groups of lignin. Finally, an evaluation of the dissociation energy of the NO-H bond of HBT, which is not accessible exptl., is provided by the use of a thermochem. cycle and theor. calculations

New Journal of Chemistry published new progress about 183303-74-4. 183303-74-4 belongs to ethers-buliding-blocks, auxiliary class Benzene,Alcohol,Ether, name is 1-(3,4-Dimethoxyphenyl)-2-phenoxyethanol, and the molecular formula is C16H18O4, Synthetic Route of 183303-74-4.

Referemce:
https://en.wikipedia.org/wiki/Ether,
Ether | (C2H5)2O – PubChem

Baciocchi, Enrico published the artcileOxidation of non-phenolic β-O-aryl-lignin model dimers catalyzed by lignin peroxidase. Comparison with the oxidation induced by potassium 12-tungstocobalt(III)ate, HPLC of Formula: 183303-74-4, the publication is Journal of the Chemical Society, Perkin Transactions 2 (2001), 1506-1511, database is CAplus.

The H₂O₂-promoted oxidations of the non-phenolic β-O-aryl-lignin model dimers 1-(3,4-dimethoxyphenyl)-2-phenoxyethanol (I) and 2-(4-methoxyphenoxy)-1-phenylethanol (II) catalyzed by lignin peroxidase (III) at pH =4.0 were studied. The oxidation of I mainly leads to the corresponding ketone, indicating that the prevailing reaction of the intermediate radical cation I^+· is Cα-H deprotonation. The oxidation of II forms 2-(4-methoxyphenoxy)-2-phenylethanol, an isomer of II, 2-phenyl-1,4-dioxaspiro[4,5]deca-6,9-dien-8-one (IV), and products coming from the cleavage of the C-C bond γ to the more electron rich ring. The formation of all of these products can be rationalized by assuming that the main reaction of the intermediate II^+· is a nucleophilic attack of the alc. OH group on the ring bearing the pos. charge. This leads to a spirocyclohexadienyl radical, which either is then oxidized to the dioxaspirodecadienone IV or undergoes ring opening to give an alkoxyl radical from which the isomer of II and the C-C bond cleavage products may form. Support for this mechanism was provided by a study of the oxidation of 4-MeOC₆H₄OCH₂CD₂OH and by comparing the results with those obtained when the alkoxyl radical 4-MeOC₆H₄OCH₂CD₂O^· was generated from 4-MeOC₆H₄OCH₂CD₂OOt-Bu. The oxidation of I induced by the genuine one-electron oxidant K 12-tungstocobalt(III)ate (V) at pH =4.0 confirms the results obtained with III. However, under the same conditions, no fragmentation products were observed in the oxidation of II, probably because of a fast oxidation, by V, of the spirocyclohexadienyl radical.

Journal of the Chemical Society, Perkin Transactions 2 published new progress about 183303-74-4. 183303-74-4 belongs to ethers-buliding-blocks, auxiliary class Benzene,Alcohol,Ether, name is 1-(3,4-Dimethoxyphenyl)-2-phenoxyethanol, and the molecular formula is C16H18O4, HPLC of Formula: 183303-74-4.

Referemce:
https://en.wikipedia.org/wiki/Ether,
Ether | (C2H5)2O – PubChem

Annunziatini, Claudia published the artcileAryl substituted N-hydroxyphthalimides as mediators in the laccase-catalyzed oxidation of lignin model compounds and delignification of wood pulp, Product Details of C16H18O4, the publication is Journal of Molecular Catalysis B: Enzymatic (2005), 32(3), 89-96, database is CAplus.

Aryl substituted N-hydroxyphthalimides (NHPIs) have been tested as mediators in the laccase-promoted oxidation of non-phenolic monomeric and dimeric lignin model compounds and in the delignification of kraft pulp samples. In the oxidation of the model compounds a significant increase in the product yields was observed upon increasing the electron donating properties of the NHPI ring substituent. Product yields also increased, but to a smaller extent, by increasing the electron donating properties of the aromatic substituent in the lignin models. These results suggest the contribution to the overall reactivity of both the oxidation of the aryl substituted NHPI to the N-oxyl radical (X-PINO) by laccase and the hydrogen atom transfer step from the substrate to the X-PINO, with a major contribution of the former process. When applied to the delignification of kraft pulps again the mediation efficiency increased by increasing the electron donating properties of the NHPI aryl substituent, the best mediators being 4-Me-NHPI and 4-MeO-NHPI. Thus, the use of non-phenolic lignin model compounds in the oxidation promoted by the laccase/X-NHPI system is well suited to mimic the behavior of the lignin polymer.

Journal of Molecular Catalysis B: Enzymatic published new progress about 183303-74-4. 183303-74-4 belongs to ethers-buliding-blocks, auxiliary class Benzene,Alcohol,Ether, name is 1-(3,4-Dimethoxyphenyl)-2-phenoxyethanol, and the molecular formula is C16H18O4, Product Details of C16H18O4.

Referemce:
https://en.wikipedia.org/wiki/Ether,
Ether | (C2H5)2O – PubChem

Shimizu, Satoko published the artcileChemical factors underlying the more rapid β-O-4 bond cleavage of syringyl than guaiacyl lignin under alkaline delignification conditions, Formula: C16H18O4, the publication is Journal of Wood Chemistry and Technology (2017), 37(6), 451-466, database is CAplus.

This study aimed to clarify why the β-O-4 bond cleavage of syringyl lignin is more rapid than that of guaiacyl lignin under alk. pulping conditions. We examined whether or not three chem. factors, acidity of the α-hydroxy group, nucleophilicity of the generated α-alkoxide, and leaving ability of the leaving phenoxide, are different between syringyl and guaiacyl lignins and control the rate of the alk.-induced β-O-4 bond cleavage, employing dimeric non-phenolic β-O-4-type lignin model compounds (LMCs) and novel methods for estimating these three factors. The results indicated that the α-hydroxy groups of syringyl-type LMCs are relatively more acidic than those of guaiacyl-type and that syringyl nucleus is a better leaving group than guaiacyl nucleus in the β-O-4 bond cleavage. These factors result in the β-O-4 bond of syringyl lignin being more prone to the alk.-induced cleavage than that of guaiacyl lignin.

Journal of Wood Chemistry and Technology published new progress about 183303-74-4. 183303-74-4 belongs to ethers-buliding-blocks, auxiliary class Benzene,Alcohol,Ether, name is 1-(3,4-Dimethoxyphenyl)-2-phenoxyethanol, and the molecular formula is C4H5BN2O2, Formula: C16H18O4.

Referemce:
https://en.wikipedia.org/wiki/Ether,
Ether | (C2H5)2O – PubChem