40421-52-1Relevant articles and documents
Lipase-Catalyzed Transesterification as a Practical Route to Homochiral Acyclic anti-1,2-Diols. A New Syntesis of (+)- and (-)-endo-Brevicomin.
Kim, Mahn-Joo,Choi, Gil-Bae,Kim, Joon-Joung,Kim, Hee-Jeong
, p. 6253 - 6256 (1995)
Several anti-1,2-diols (2a-g) have been efficiently resolved by using LPS-catalyzed transesterification and the total synthesis of (+)- and (-)-endo-brevicomin (1) has been achieved starting from one (2g) of the resolved diols.
Temperature and pH dependence of Enzyme-catalyzed hydrolysis of trans-methylstyrene oxide. A unifying kinetic model for observed hysteresis, Cooperativity, and regioselectivity
Lindberg, Diana,De La Revenga, Mario Fuente,Widersten, Mikael
, p. 2297 - 2304 (2010)
The underlying enzyme kinetics behind, the regioselective promiscuity shown by epoxide hydrolases toward, certain epoxides has been studied. The effects of temperature and pH on regioselectivity were investigated by analyzing the stereochemistry of hydrolysis products of (1R,2R)-trans-2-methylstyrene oxide between 14-46 °C and pH 6.0-9.0, either catalyzed by the potato epoxide hydrolase StEH1 or in the absence of enzyme. In the enzyme-catalyzed reaction, a switch of preferred, epoxide carbon that is subjected to nucleophilic attack is observed at pH values above 8. The enzyme also displays cooperativity in substrate saturation plots when assayed at temperatures ≤30 °C and at intermediate pH. The cooperativity is lost at higher assay temperatures. Cooperativity can originate from, a kinetic mechanism involving hysteresis and will be dependent on. the relationship between Kcat and the rate of interconversion between two different Michaelis complexes. In the case of the studied reactions, the proposed different Michaelis complexes are enzyme-substrate complexes in which the epoxide substrate is bound in different binding modes, allowing for separate pathways toward product formation. The assumption of separated, but interacting, reaction pathways is supported by that formation of the two product enantiomers also displays distinct pH dependencies of Kcat/ KM The thermodynamic parameters describing the differences in activation enthalpy and entropy suggest that (1) regioselectivity is primarily dictated by differences in activation entropy with positive values of both ΔΔ?H and ΔΔ ? and (2) the hysteretic behavior is linked, to an interconversion between Michaelis complexes with rates increasing with temperature. From the collected data, we propose that hysteresis, regioselectivity, and, when applicable, hysteretic cooperativity are closely linked properties, explained by the kinetic mechanism earlier introduced by our group.
Mutations in salt-bridging residues at the interface of the core and lid domains of epoxide hydrolase StEH1 affect regioselectivity, protein stability and hysteresis
Lindberg, Diana,Ahmad, Shabbir,Widersten, Mikael
, p. 165 - 173 (2010)
Epoxide hydrolase, StEH1, shows hysteretic behavior in the catalyzed hydrolysis of trans-2-methylstyrene oxide (2-MeSO)1Abbreviations used: SO, styrene oxide; 2-MeSO, trans-2-methylstyrene oxide.1. Linkage between protein structure dynamics and catalytic function was probed in mutant enzymes in which surface-located salt-bridging residues were substituted. Salt-bridges at the interface of the α/β-hydrolase fold core and lid domains, as well as between residues in the lid domain, between Lys179-Asp202, Glu215-Arg41 and Arg236-Glu165 were disrupted by mutations, K179Q, E215Q, R236K and R236Q. All mutants displayed enzyme activity with styrene oxide (SO) and 2-MeSO when assayed at 30 °C. Disruption of salt-bridges altered the rates for isomerization between distinct Michaelis complexes, with (1R,2R)-2-MeSO as substrate, presumably as a result of increased dynamics of involved protein segments. Another indication of increased flexibility was a lowered thermostability in all mutants. We propose that the alterations to regioselectivity in these mutants derive from an increased mobility in protein segments otherwise stabilized by salt bridging interactions.
Electrochemically Tuned Oxidative [4+2] Annulation and Dioxygenation of Olefins with Hydroxamic Acids
Wei, Bang-Yi,Xie, Dong-Tai,Lai, Sheng-Qiang,Jiang, Yu,Fu, Hong,Wei, Dian,Han, Bing
supporting information, p. 3182 - 3188 (2020/12/11)
This work represents the first [4+2] annulation of hydroxamic acids with olefins for the synthesis of benzo[c][1,2]oxazines scaffold via anode-selective electrochemical oxidation. This protocol features mild conditions, is oxidant free, shows high regioselectivity and stereoselectivity, broad substrate scope of both alkenes and hydroxamic acids, and is compatible with terpenes, peptides, and steroids. Significantly, the dioxygenation of olefins employing hydroxamic acid is also successfully achieved by switching the anode material under the same reaction conditions. The study not only reveals a new reactivity of hydroxamic acids and its first application in electrosynthesis but also provides a successful example of anode material-tuned product selectivity.
Synthesis of α-hydroxy ketones and vicinal (R, R)-diols by Bacillus clausii DSM 8716T butanediol dehydrogenase
Bongaerts, Johannes,Jablonski, Melanie,Kipp, Carina Ronja,Molinnus, Denise,Muschallik, Lukas,Pohl, Martina,Sch?ning, Michael J.,Selmer, Thorsten,Siegert, Petra,Wagner, Torsten
, p. 12206 - 12216 (2020/04/20)
α-hydroxy ketones (HK) and 1,2-diols are important building blocks for fine chemical synthesis. Here, we describe the R-selective 2,3-butanediol dehydrogenase from B. clausii DSM 8716T (BcBDH) that belongs to the metal-dependent medium chain dehydrogenases/reductases family (MDR) and catalyzes the selective asymmetric reduction of prochiral 1,2-diketones to the corresponding HK and, in some cases, the reduction of the same to the corresponding 1,2-diols. Aliphatic diketones, like 2,3-pentanedione, 2,3-hexanedione, 5-methyl-2,3-hexanedione, 3,4-hexanedione and 2,3-heptanedione are well transformed. In addition, surprisingly alkyl phenyl dicarbonyls, like 2-hydroxy-1-phenylpropan-1-one and phenylglyoxal are accepted, whereas their derivatives with two phenyl groups are not substrates. Supplementation of Mn2+ (1 mM) increases BcBDH's activity in biotransformations. Furthermore, the biocatalytic reduction of 5-methyl-2,3-hexanedione to mainly 5-methyl-3-hydroxy-2-hexanone with only small amounts of 5-methyl-2-hydroxy-3-hexanone within an enzyme membrane reactor is demonstrated.
