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61.
The product pattern found for the dimethyldioxirane-mediated oxidation of phenylethyne strongly depends on the reaction conditions. Dimethyldioxirane generated in situ from caroate (HSO(5)(-)) 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 benzoylcarbene. Subsequent Wolff rearrangement produces intermediate phenylketene, which can be trapped by water as phenylacetic acid or suffer from further oxidation to the alpha-lactone of mandelic acid. The alpha-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 unrearranged 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 alpha-lactone by dimethyldioxirane. Under in situ conditions benzoic acid is also formed by caroate initiated oxidative decarboxylation of phenylglyoxylic acid and/or intermediate phenylglyoxal. 相似文献
62.
L. Michaelis Bertrand Kraus und Adler 《Fresenius' Journal of Analytical Chemistry》1915,54(5):285-288
Ohne Zusammenfassung 相似文献
63.
C. Matignon G. Marchal W. Bothe O. Erbacher K. Philipp K. Donat O. Hahn J. Heidenhain J. St. van der Lingen F. Tödt O. von Baeyer Lise Jette W. West F. Paneth P. Beer F. Richter K. Horovitz A. Lottermoser F. Haber K. Fajans K. v. Beckerath L. Michaelis Sh. Dokan J. N. Mukherjee M. Centnerszwer M. Straumanis T. Isnardi I. Langmuir 《Analytical and bioanalytical chemistry》1932,87(5-6):200-211
64.
65.
Soo Sung Ko Larry L Klein Klaus-Peter Pfaff Yoshito Kishi 《Tetrahedron letters》1982,23(43):4415-4418
A stereocontrolled and practical synthetic route to the acetal , a degradation product of palytoxin, in optically active form is described. 相似文献
66.
On the Hydrolysis of Iron (III) Salt Solutions. II. Ageing of Hydrolysis Products The long time ageing up to 15 years of the products obtained by alkalifying iron(III) chloride solutions to different neutralisation degrees has been studied. The concentration of the Fe3+ and the Cl- ions, the strength of the alkali, and the rate of its addition influence the results. Slow alkalifying produced up to 90% neutralisation β-FeOOH. The transformation of the amorphous iron(III) oxidehydroxide to β-FeOOH was promoted by a high concentration of the Cl- ions. When a large amount of amorphous iron(III) oxidehydroxide was formed, intimately intergrown crystals of α- and β-FeOOH resulted. On further ageing β-FeOOH transformed into α-FeOOH. At a degree of neutralisation of 95 and 100% transformation of the amorphous iron(III) oxidehydroxide into α-Fe2O3 occurred. The 100% neutralized precipitate, however, remained partly amorphous. Authors discuss the factors that determine very slow reactions leading to these results. 相似文献
67.
Chris Gendy Akseli Mansikkamki Juuso Valjus Joshua Heidebrecht Paul Chuk‐Yan Hui Guy M. Bernard Heikki M. Tuononen Roderick E. Wasylishen Vladimir K. Michaelis Roland Roesler 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(1):160-164
Flexible, chelating bis(NHC) ligand 2 , able to accommodate both cis‐ and trans‐coordination modes, was used to synthesize ( 2 )Ni(η2‐cod), 3 . In reaction with GeCl2, it produced ( 2 )NiGeCl2, 4 , featuring a T‐shaped Ni0 and a pyramidal Ge center. Complex 4 could also be prepared from [( 2 )GeCl]Cl, 5 , and Ni(cod)2, in a reaction that formally involved Ni–Ge transmetalation, followed by coordination of the extruded GeCl2 moiety to Ni. A computational analysis showed that 4 possesses considerable multiconfigurational character and the Ni→Ge bond is formed through σ‐donation from the Ni 4s, 4p, and 3d orbitals to Ge. (NHC)2Ni(cod) complexes 9 and 10 , as well as (NHC)2GeCl2 derivative 11 , incorporating ligands that cannot accommodate a wide bite angle, failed to produce isolable Ni–Ge complexes. The isolation of ( 2 )Ni(η2‐Py), 12 , provides further evidence for the reluctance of the ( 2 )Ni0 fragment to act as a σ‐Lewis acid. 相似文献
68.
Liebmann T. Heubner C. Schneider M. Michaelis A. 《Journal of Solid State Electrochemistry》2019,23(1):245-250
Journal of Solid State Electrochemistry - Recently, considerable improvements regarding the electrochemical performance of cathodes for lithium-ion batteries have been achieved by combining... 相似文献
69.
Carl L. Alsberg P. Rona L. Michaelis B. Oppler und Ivar Bang 《Fresenius' Journal of Analytical Chemistry》1910,49(1):66-67
Ohne Zusammenfassung 相似文献
70.
W. Claus P. E. Klopsteg H. Menzel F. Krüger N. Bjerrum W. Nernst M. Planck P. Henderson Erich Müller R. Luther L. Michaelis Alfred Schmid M. Trénel A. Lessing F. Haber R. Russ E. Greppi C. Lucchini V. K. La Mer T. R. Parsons E. Little E. M. Durand O. Tomiek W. A. Roth J. C. Baker und L. L. van Slyke 《Fresenius' Journal of Analytical Chemistry》1930,79(3-4):137-145
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