2788-86-5Relevant articles and documents
Green oxidation of olefins and methyl phenyl sulfide with hydrogen peroxide catalyzed by an oxovanadium(IV) Schiff base complex encapsulated in the nanopores of zeolite-Y
Rayati, Saeed,Salehi, Fatemeh
, p. 309 - 315 (2015)
Oxovanadium(IV) complex of a Schiff base ligand derived from 2,4-dihydroxyacetophenone and 2,2′-dimethylpropanediamine has been encapsulated in the nanopores of zeolite-Y by flexible ligand method and characterized by metal analysis, IR spectroscopic studies and X-ray diffraction patterns. The encapsulated complex [VOL-Y] catalyzes the oxidation of various olefins and methyl phenyl sulfide using hydrogen peroxide as a green oxidant in good yield. Under the optimized reaction conditions, in the presence of VOL-Y, 86 % conversion of cyclooctene with 100 % selectivity for epoxide and 51 % conversion for methyl phenyl sulfide with 92 % selectivity for sulfone were obtained.
The Stereoselective Oxidation of para-Substituted Benzenes by a Cytochrome P450 Biocatalyst
Chao, Rebecca R.,Lau, Ian C.-K.,Coleman, Tom,Churchman, Luke R.,Child, Stella A.,Lee, Joel H. Z.,Bruning, John B.,De Voss, James J.,Bell, Stephen G.
, p. 14765 - 14777 (2021/09/14)
The serine 244 to aspartate (S244D) variant of the cytochrome P450 enzyme CYP199A4 was used to expand its substrate range beyond benzoic acids. Substrates, in which the carboxylate group of the benzoic acid moiety is replaced were oxidised with high activity by the S244D mutant (product formation rates >60 nmol.(nmol-CYP)?1.min?1) and with total turnover numbers of up to 20,000. Ethyl α-hydroxylation was more rapid than methyl oxidation, styrene epoxidation and S-oxidation. The S244D mutant catalysed the ethyl hydroxylation, epoxidation and sulfoxidation reactions with an excess of one stereoisomer (in some instances up to >98 %). The crystal structure of 4-methoxybenzoic acid-bound CYP199A4 S244D showed that the active site architecture and the substrate orientation were similar to that of the WT enzyme. Overall, this work demonstrates that CYP199A4 can catalyse the stereoselective hydroxylation, epoxidation or sulfoxidation of substituted benzene substrates under mild conditions resulting in more sustainable transformations using this heme monooxygenase enzyme.
Structural and Biochemical Studies Enlighten the Unspecific Peroxygenase from Hypoxylon sp. EC38 as an Efficient Oxidative Biocatalyst
Ebner, Katharina,Glieder, Anton,Kroutil, Wolfgang,Mattevi, Andrea,Rinnofner, Claudia,Rotilio, Laura,Swoboda, Alexander
, p. 11511 - 11525 (2021/09/22)
Unspecific peroxygenases (UPOs) are glycosylated fungal enzymes that can selectively oxidize C-H bonds. UPOs employ hydrogen peroxide as the oxygen donor and reductant. With such an easy-to-handle cosubstrate and without the need for a reducing agent, UPOs are emerging as convenient oxidative biocatalysts. Here, an unspecific peroxygenase from Hypoxylon sp. EC38 (HspUPO) was identified in an activity-based screen of six putative peroxygenase enzymes that were heterologously expressed in Pichia pastoris. The enzyme was found to tolerate selected organic solvents such as acetonitrile and acetone. HspUPO is a versatile catalyst performing various reactions, such as the oxidation of prim- and sec-alcohols, epoxidations, and hydroxylations. Semipreparative biotransformations were demonstrated for the nonenantioselective oxidation of racemic 1-phenylethanol rac-1b (TON = 13 000), giving the product with 88% isolated yield, and the oxidation of indole 6a to give indigo 6b (TON = 2800) with 98% isolated yield. HspUPO features a compact and rigid three-dimensional conformation that wraps around the heme and defines a funnel-shaped tunnel that leads to the heme iron from the protein surface. The tunnel extends along a distance of about 12 ? with a fairly constant diameter in its innermost segment. Its surface comprises both hydrophobic and hydrophilic groups for dealing with substrates of variable polarities. The structural investigation of several protein-ligand complexes revealed that the active site of HspUPO is accessible to molecules of varying bulkiness with minimal or no conformational changes, explaining the relatively broad substrate scope of the enzyme. With its convenient expression system, robust operational properties, relatively small size, well-defined structural features, and diverse reaction scope, HspUPO is an exploitable candidate for peroxygenase-based biocatalysis.
MeOTf/KI-catalyzed efficient synthesis of 2-arylnaphthalenesviacyclodimerization of styrene oxides
Chen, Chao,Xi, Chanjuan,Zhang, Zeyu,Zou, Song
supporting information, p. 8559 - 8565 (2021/10/20)
The MeOTf/KI-catalyzed synthesis of 2-arylnaphthalene derivatives from aryl ethylene oxides in alcohol under ambient conditions is described. The present protocol has a higher atom efficiency and wider substrate applicability with excellent yields. The reaction proceeded using the aryl ethylene oxides to give 2-arylnaphthalenes either in homo-coupling or in cross-coupling. The reaction could also be carried out at the gram scale in minutes.
