Academic literature on the topic '2,6-dichloro-1,4-benzoquinone'

ABSTRACT Under secondary metabolic conditions, the lignin-degrading basidiomycete Phanerochaete chrysosporium mineralizes 2,4,6-trichlorophenol. The pathway for the degradation of 2,4,6-trichlorophenol has been elucidated by the characterization of fungal metabolites and oxidation products generated by purified lignin peroxidase (LiP) and manganese peroxidase (MnP). The multistep pathway is initiated by a LiP- or MnP-catalyzed oxidative dechlorination reaction to produce 2,6-dichloro-1,4-benzoquinone. The quinone is reduced to 2,6-dichloro-1,4-dihydroxybenzene, which is reductively dechlorinated to yield 2-chloro-1,4-dihydroxybenzene. The latter is degraded further by one of two parallel pathways: it either undergoes further reductive dechlorination to yield 1,4-hydroquinone, which isortho-hydroxylated to produce 1,2,4-trihydroxybenzene, or is hydroxylated to yield 5-chloro-1,2,4-trihydroxybenzene, which is reductively dechlorinated to produce the common key metabolite 1,2,4-trihydroxybenzene. Presumably, the latter is ring cleaved with subsequent degradation to CO2. In this pathway, the chlorine at C-4 is oxidatively dechlorinated, whereas the other chlorines are removed by a reductive process in which chlorine is replaced by hydrogen. Apparently, all three chlorine atoms are removed prior to ring cleavage. To our knowledge, this is the first reported example of aromatic reductive dechlorination by a eukaryote.

Charge-transfer interactions of octaethylporphycenatozinc(II), ( OEPc ) Zn with 2,6-dichloro-3,5-dicyano-1,4-benzoquinone, DDQ, in non-aqueous solvents are reported. Both optical absorption and cyclic voltammetry studies reveal the formation of stable charge-transfer complexes between ( OEPc ) Zn and DDQ. New redox couples corresponding to reduction of the charge-transfer complex have been electrochemically detected. The formation of charge-transfer complexes between ( OEPc ) Zn and doubly reduced DDQ is examined and the present electrochemical studies reveal the possible existence of such complexes in solution. Based on semiempirical AM1 and PM3 calculations, interaction through the zinc(II) metal center of ( OEPc ) Zn and cyanide nitrogen of the quinone is proposed.

Allyl 2,6-di-O-benzyl-α-D-galactopyranoside was converted by tin-mediated alkylation into the 3-O-p-methoxybenzyl ether which gave the 4-O-mesyl derivative. Sodium benzoate in refluxing N,N-dimethylformamide converted the last compound into allyl 4-O-benzoyl-2,6-di-O-benzyl-3-O-p-methoxybenzyl-α-D-glucopyranoside in high yield. This was saponified and the product was treated with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone to give the required allyl 2,6-di-O-benzyl-α-D-glucopyranoside whose structure was confirmed by conversion into the known 2,3,4,6-tetra-O-benzyl-D-glucopyranose. Removal of the allyl group from allyl 2,6-di-O-benzyl-α-D-glucopyranoside by a standard procedure gave 2,6-di-O-benzyl-D-glucopyranose. Both of the title compounds are required as intermediates for the synthesis of analogues of the 'adenophostins'.

Cardinalic acid (1,7,8-trihydroxy-6-methoxy-3-methyl-9,10-dioxoanthracene-2-carboxylic acid) (4) and the known anthraquinone carboxylic acids endocrocin (1), dermolutein (2) and cinnalutein (3) have been isolated from the New Zealand toadstool Dermocybe cardinalis. Methyl 1,7,8-tri-O-methylcardinalate (5) has been prepared both by permethylation of the natural product (4) and from 2,6-dichloro-1,4-benzoquinone by two consecutive regioselective Diels–Alder cycloaddition reactions. A single-crystal X-ray structure analysis of the ester (5) corroborates the structure of the natural product (4) and confirms the outcome of both cycloaddition reactions.

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The 2,6-dichloro-1,4-benzoquinone (DCBQ), a subproduct of the water disinfection process, is a highly reactive molecule and has a redox cycle with its semiquinone radicals that lead to the formation of reactive oxygen species (ROS). These species can cause severe oxidative stress in cells leading to the formation of macromolecules, such as oxidized lipids, proteins and DNA. The induced cell damage occur through alkylation of proteins and/or DNA, moreover understanding how this occurs is very complex. Thus, the study of the electrochemical behaviour of DCBQ before and after degradation in aqueous solution on glassy carbon electrode, as well as the investigation of DCBQ and DNA using dsDNAelectrochemical biosensors were performed. The DCBQ showed a reversible process at pH range from 3.7 to 12.6 when was evaluated by cyclic voltammetry. For differential pulse voltammetry the peak potential of DCBQ was pH-dependent until pH 9.2. After successive scans occurred the formation of a reversible oxidation product in a pH-dependent process to pH 5.4. The electrochemical behaviour of DCBQ and its oxidation products was also investigated by square wave voltammetry. The reversibility of these two redox processes was confirmed in a wide range of pH. By varying incubation time and electrolyte solutions, DCBQ showed spontaneous degradation which was electrochemically detected by the decrease of the current peak and appearance of a new oxidation peak at less positive potential. The oxidation of the degraded DCBQ was a reversible and pH-dependent process in the pH values of 3.7 ≤ pH ≤ 6.0. Moreover, the degradation of DCBQ in aqueous solution was confirmed by UV-Vis spectrophotometry experiments. Using incubated dsDNA solutions and dsDNA-electrochemical biosensors, it was observed that the DCBQ and pdDCBQ interacted with the dsDNA, through the release of the bases Gua and Ade. The interaction of DCBQ-dsDNA did not show any oxidative damage to DNA by the product(s) formed by DCBQ, since the 8-oxoGua/2,8-DHA was not detected. An analytical methodology for the determination of DCBQ, using gold microelectrode and square wave voltammetry, was developed in the range of 19.9 to 291.0 μmol L-1. The detection and quantification limits of 6.1 and 20.3 μmol L-1, respectively were detected.
A 2,6-dicloro-1,4-benzoquinona (DCBQ), um subproduto do processo de desinfecção da água, é uma molécula altamente reativa e apresenta um ciclo redox com seus radicais semiquinonas que levam à formação de espécies reativas de oxigênio (ERO). Essas espécies podem causar estresse oxidativo grave dentro de células por meio da formação de macromoléculas, como lipídios oxidados, proteínas e DNA. A compreensão de como isso ocorre é muito complexa e os danos celulares gerados se dão por meio de alquilação de proteínas e/ou DNA. Diante disso, um estudo do comportamento eletroquímico da DCBQ antes e após a sua degradação em solução aquosa sobre eletrodo de carbono vítreo (ECV) e a investigação da DCBQ com DNA, utilizando biossensores eletroquímicos de dsDNA (do inglês double stranded Desoxyribonucleic Acid), foram realizados. A DCBQ foi investigada inicialmente por voltametria cíclica (VC), apresentando um processo reversível no intervalo de pH de 3,7 a 12,6. Por voltametria de pulso diferencial (VPD) observou-se que o potencial de pico da DCBQ é dependente do pH da solução até pH 9,2. Após varreduras de potencial sucessivas, observou-se a formação de um produto de oxidação reversivelmente oxidado em um processo dependente do pH até pH 5,4. O comportamento eletroquímico da DCBQ e do seu produto de oxidação foram investigados por VOQ, confirmando, assim, a reversibilidade desses dois processos redox em toda a faixa de pH estudada. Após vários períodos de incubação, em diferentes eletrólitos, a degradação espontânea da DCBQ foi detectada eletroquimicamente pelo decaimento da sua corrente de pico e o aparecimento de um novo pico de oxidação, em potencial menos positivo. A oxidação da DCBQ degradada é um processo reversível e dependente do pH para valores de 3,7 ≤ pH ≤ 6,0. A degradação da DCBQ em solução aquosa foi confirmada por meio de experimentos realizados por espectrofotometria UV-Vis. Utilizando soluções de dsDNA incubadas e biossensores eletroquímicos de dsDNA, observou-se que a DCBQ e o(s) pdDCBQ (produtos de degradação da DCBQ) interagiram com o dsDNA, através da liberação das bases Gua e Ade. A interação da DCBQ-dsDNA não mostrou nenhum dano oxidativo causado ao DNA pelo(s) produtos(s) formados pela DCBQ, visto que a 8- oxoGua/2,8-DHA não foi detectada. Uma metodologia analítica, utilizando microeletrodo de ouro e VOQ foi desenvolvida para a determinação da DCBQ, obtendo-se um intervalo linear de 19,9 a 291,0 μmol L-1 com limites de detecção e de quantificação de 6,1 e 20,3 µmol L-1, respectivamente.