95-87-4Relevant articles and documents
Mediated electron transfer with monooxygenases - Insight in interactions between reduced mediators and the co-substrate oxygen
Tosstorff, Andreas,Dennig, Alexander,Ruff, Anna Jo?lle,Schwaneberg, Ulrich,Sieber, Volker,Mangold, Klaus-Michael,Schrader, Jens,Holtmann, Dirk
, p. 51 - 58 (2014)
One of the most important obstacles to overcome in biocatalysis with monooxygenases is the enzyme's dependency on the costly redox cofactor NAD(P)H. Electrochemical regeneration systems, in which an electrode serves as electron donor, provide an alternative route to enzymatic redox reactions. Mediators are often used to accelerate electron transfer between electrode and enzyme. We investigated the mediated bioelectrochemical conversion of p-xylene to 2,5-dimethylphenol (2,5-DMP) by a P450 BM3 variant and were able to produce 2,5-DMP electrochemically. Due to the fact that mediator reduction is limited by the electrode surface a scale-up was performed. However, increasing the electrode surface area to reactor volume ratio led to a drastic increase in cathodic oxygen reduction, causing a drop in product formation. It was shown that reduced cobalt sepulchrate reacts with the co-substrate oxygen. Furthermore, the reportedly oxygen stable mediator [Cp*Rh(I)(bpy)H] + was compared to cobalt sepulchrate. While its turnover frequency is of comparable magnitude to cobalt sepulchrate when transferring the electrons between electrode and enzyme, using NADP+ as intermediary between the mediator and the enzyme significantly increased the mediator's turnover frequency. The rhodium mediator [Cp*Rh(I)(bpy)H]+ does not appear to be significantly more oxygen stable.
Method for synthesizing 2-5 -dimethylphenol
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Paragraph 0021; 0024-0025; 0028-0087, (2021/02/24)
The invention discloses a method for synthesizing 2,5-dimethyl phenol. The method comprises the steps: utilizing 2,5-dimehtyl-benzenesulfonic acid as a raw material, supercritical distilled water as areaction medium, sodium hydroxide as a catalyst and oxygen as an oxidant; reacting to obtain a 2,5-dimethyl phenol crude product; finally, sequentially filtering, ethanol refining and filtering and drying to obtain a 2,5-dimethyl phenol pure product. The method disclosed by the invention utilizes the supercritical water to synthesize the 2,5-dimethyl phenol, so that the method is the most appropriate method in the present; reaction steps are reduced, and a technological process is shortened; thus, the environmental pollution problem is fundamentally solved, and no three wastes (waste water, waste gas and waste solid) are generated. Therefore, according to the method disclosed by the invention, the technology utilizing the supercritical water to synthesize the 2,5-dimethyl phenol has a very obvious effect.
Regioselectivity of Hydroxyl Radical Reactions with Arenes in Nonaqueous Solutions
Moores, Lee C.,Kaur, Devinder,Smith, Mathew D.,Poole, James S.
, p. 3260 - 3269 (2019/03/11)
The regioselectivity of hydroxyl radical addition to arenes was studied using a novel analytical method capable of trapping radicals formed after the first elementary step of reaction, without alteration of the product distributions by secondary oxidation processes. Product analyses of these reactions indicate a preference for o- over p-substitution for electron donating groups, with both favored over m-addition. The observed distributions are qualitatively similar to those observed for the addition of other carbon-centered radicals, although the magnitude of the regioselectivity observed is greater for hydroxyl. The data, reproduced by high accuracy CBS-QB3 computational methods, indicate that both polar and radical stabilization effects play a role in the observed regioselectivities. The application and potential limitations of the analytical method used are discussed.