60764-00-3Relevant academic research and scientific papers
Reducing versus basic properties of 1,2-diaryl-1,2-disodioethanes
Azzena, Ugo,Dettori, Giovanna,Pisano, Luisa,Pittalis, Mario
experimental part, p. 3470 - 3475 (2011/06/17)
The outcome of the reaction between halogenated arylacetic acids and 1,2-diaryl-1,2-disodioethanes strongly depends on the nature of both reaction partners, and it can be rationalized in terms of a competition between reducing and basic properties of the vic-diorganometals, as well as of the ease of the reductive cleavage of the different carbon-halide bonds. As an application of these findings, we developed a particularly mild approach to the synthesis of halogenated and non halogenated α-substituted arylacetic acids.
Engineering the promiscuous racemase activity of an arylmalonate decarboxylase
Kourist, Robert,Miyauchi, Yusuke,Uemura, Daisuke,Miyamoto, Kenji
experimental part, p. 557 - 563 (2011/03/21)
Variant G74C of arylmalonate decarboxylase (AMDase) from Bordatella bronchoseptica has a unique racemising activity towards profens. By protein engineering, variant G74C/V43A with a 20-fold shift towards promiscuous racemisation was obtained, based on a reduced activity in the decarboxylation reaction and a two-fold increase in the racemisation activity. The mutant showed an extended substrate range, with a 30-fold increase in the reaction rate towards ketoprofen. Molecular dynamics simulations and the substrate profile of the racemase indicate that the steric and polar effects of the substrate structure play a more dominant role on catalysis than mere kinetic α-proton acidity. The observation that the conversion of β,γ-unsaturated carboxylic acids does not lead to a rearrangement to form their α,β isomers indicates a concerted rather than a stepwise mechanism. Interestingly, a substrate bearing a nitro group instead of the carboxylic acid group on the α-carbon atom was also converted by the racemase.
Oxidative amide synthesis and N-terminal α-amino group ligation of peptides in aqueous medium
Chan, Wing-Kei,Ho, Chi-Ming,Wong, Man-Kin,Che, Chi-Ming
, p. 14796 - 14797 (2008/02/05)
A new method for oxidative synthesis of amides from alkynes and amines in high yields (up to 96%) using [Mn(2,6-Cl2TPP)Cl] 1 as a catalyst and Oxone/H2O2 as an oxidant in aqueous medium has been developed. This method could be used for N-terminal α-amino group ligation of unprotected peptides with aryl, aliphatic, and internal alkynes under mild conditions. Copyright
The dimethyldioxirane-mediated oxidation of phenylethyne
Zeller, Klaus-Peter,Kowallik, Meike,Haiss, Peter
, p. 2310 - 2318 (2007/10/03)
The product pattern found for the dimethyldioxirane-mediated oxidation of phenylethyne strongly depends on the reaction conditions. Dimethyldioxirane generated in situ from caroate (HSO5) and acetone in acetonitrile-water furnishes phenylacetic acid as the main product. With solutions of dimethyldioxirane in acetone, mandelic acid and phenylacetic acid are mainly formed. The relative abundances of the two acids depend on the residual water present in the dimethyldioxirane-acetone solution. Application of thoroughly dried solutions of the reagent effects increased formation of mandelic acid. When phenylethyne is oxidized by dimethyldioxirane transferred into tetrachloromethane, to minimize traces of water even further, oligomeric mandelic acid is obtained. The results are rationalized by the initial formation of phenyloxirene, which is known to equilibrate with phenylformylcarbene and bcnzoylcarbene. Subsequent Wolff rearrangement produces intermediate phenylketene, which can be trapped by water as phenylacetic acid or suffer from further oxidation to the α-lactone of mandelic acid. The α-lactone can either react with water to yield mandelic acid or, under anhydrous conditions, to yield oligomeric mandelic acid. In addition to mandelic acid and phenylacetic acid phenylglyoxylic acid, benzoic acid and benzaldehyde are observed as reaction products. The formation of phenylglyoxylic acid by transfer of two oxygen atoms to the in rear ranged carbon skeleton of phenylethyne followed by oxygen insertion into the aldehydic C-H bond of the intermediately formed phenylglyoxal is discussed. In a second pathway this acid is formed by partial oxidation of mandelic acid. Benzaldehyde and benzoic acid are explained as products of the oxidative degradation of the α-lactone by dimethyldioxirane. Under in situ conditions benzoic acid is also formed by caroate initiated oxidative decarboxylation of phenylglyoxylic acid and/or intermediate phenylglyoxal. The Royal Society of Chemistry 2005.
Partial oxygen migration in the photochemical wolff rearrangement - α-Oxocarben-Oxiren-isomerization or intermolecular mechanism?
Haiss, Peter,Zeller, Klaus-Peter
, p. 595 - 605 (2007/10/03)
Crossover experiments between isotopomeric species of 2-diazo-1-oxo-1-phenylethane (18O, 13C, D) establish beyond doubt that the oxygen migration accompanying the photochemical Wolff rearrangement is not the result of intermolecular
New Decarboxylation, De-ethoxycarbonylation and Desulfonylation, followed by Sulfenylation of some Half-Esters of Malonic Acids and α-Sulfonylmalonic Esters
Wladislaw, Blanka,Marzorati, Liliana,Donnici, Claudio L.
, p. 3167 - 3170 (2007/10/02)
The sulfenylation of some half-esters of malonic acids and some α-sulfonylmalonic esters with several sulfenylating reagents was investigated.Evidence was provided that in the case of the half-esters, in which NaH-dimethyl sulfoxide was employed, the formation of α,α-disulfenylated carboxylic esters may occur by two different reaction sequences, initiated either by dianion formation or decarboxylation.It is shown that, in the case of the α-sulfonylmalonic esters, in which diazabicyclooctane in refluxing toluene was employed, two competitive reactions may take place: de-ethoxycarbonylation or desulfonylation, both followed by sulfenylation.
Conformations of Unsaturated and Aromatic Alcohols; Intramolecular Hydrogen Bonding in 2-Phenylethanol
Bakke, Jan M.,Chadwick, Derek J.
, p. 223 - 230 (2007/10/02)
The conformational composition of 2-phenylethanol has been investigated by 1H NMR and IR spectroscopy of solutions at low concentration in CCl4 and CFCl3.The relative energies of the stable conformations have been estimated by molecular mechanics calculat
