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1Author    C.Requires cookie*
 Title    Die Einwirkung von Bromierungsmitteln auf Cyclopropenone  
 Abstract    yclopropenone C hem istry, V I Conversion of Cyclopropenones w ith B rom inating Agents S ig r id S. D e h m l o w u n d E c k e h a r d V. D e h m l o w Addition The synthesis of m ethyl-phenylcyclopropenone (la) is decribed. Bromination of this and of diphenylcyclopropenone yields saltlike complexes 2 which are in equilibrium with their components. Di-w-propylcyclopropenone and bromine give the ring opened product 3d. l a and N-bromosuccinimid give 4 and 5, phenyl brominated derivatives, in sulfuric acid. W ith cupric bromide substituted /S-bromoacrylic acids are formed along with cyclopropenone dimers (7). 
  Reference    (Z. Naturforsch. 30b, 404—408 [1975]; eingegangen am 26. November 1974) 
  Published    1975 
  Keywords    Complex, Ring Opening, Catalized Dimerization 
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 TEI-XML for    default:Reihe_B/30/ZNB-1975-30b-0404.pdf 
 Identifier    ZNB-1975-30b-0404 
 Volume    30 
2Author    Wolfgang Danzer, Wolfgang Beck, Michael KeublerRequires cookie*
 Title    Reaktionen von Metallcarbonylverbindungen mit Diaziridin 1 Reactions of Metal Carbonyls with Diaziridine  
 Abstract    Cyclic carbamoyl complexes (2) and (3) result from the reaction of metal carbonyl hydrides with 3,3-pentamethylen diaziridine (1). 1 is cleaved at the metal by reaction with substituted metal carbonyls of Mo and W formally into 'nitrene' and cyclohexanone imine, which are isolated as isocyanate and ketimine complexes, respectively. 1 forms adducts with cobalt and nickel(II) chlorides. 
  Reference    (Z. Naturforsch. 31b, 1360—1366 [1976]; eingegangen am 16. Juli 1976) 
  Published    1976 
  Keywords    Ring Opening, Diaziridine, Metal Carbonyls, Carbamoyl, Ketimine Complexes 
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 TEI-XML for    default:Reihe_B/31/ZNB-1976-31b-1360.pdf 
 Identifier    ZNB-1976-31b-1360 
 Volume    31 
3Author    Gabriele Wagner3, Uwe Verfürth, Rudolf Herrm, Carl KrügerRequires cookie*
 Title    Ring-Opening of (-)-Camphorsulfonim ide Derivatives and (+)-Fenchonesulfonimide by Nitronium Tetrafluoroborate  
 Abstract    Treating a derivative o f (-)-cam phorsulfonim ide (C A name: (3aS)-8,8-dimethyl-4,5,6,7-tetrahydro-3H -3a,6-m ethano-2,l-benzisothiazole 2,2-dioxide) or the isomeric (+)-fenchone-sulfonimide with nitronium tetrafluoroborate in acetonitrile does not lead to the expected products of cationic reactions, e.g. o f the Ritter reaction for halogenated compounds, but provokes a cleavage of the sulfonim ide group with the formation of a ring-opened product containing a sulfonyl fluoride and a nitroimine group. The reaction does occur only in the presence of solid nitronium tetrafluoroborate, but not after prior dissolution of the reagent. An X-ray structure of the product from (1 S)-3-e«rfo-bromocamphorsulfonimide confirms this unusual reaction. 
  Reference    Z. Naturforsch. 49b, 1150—1157 (1994); received March 30 1994 
  Published    1994 
  Keywords    Camphorsulfonimide, Nitronium Tetrafluoroborate, Ring Opening, Sulfonyl Fluoride, Nitroimine 
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 TEI-XML for    default:Reihe_B/49/ZNB-1994-49b-1150.pdf 
 Identifier    ZNB-1994-49b-1150 
 Volume    49 
4Author    Reiner Luckenbach, Nikolaus MüllerRequires cookie*
 Title    Zur elektrocyclischen Ringöffnung von Cyclopropylhalogeniden bei der Reaktion mit Natriumiodid in Aceton Electrocyclic Ring Opening of Cyclopropyl Halides in the Course of their Reaction with Sodium Iodide in Acetone  
 Abstract    Reaction of cyclopropyl halides with sodium iodide in acetone [i.e. under typical Sis-2-conditions), proceeds via ring opening to allylic systems finally yielding 1,5-hexadienes upon dimerisation; ring-retained products were not detected. Application of the Wood-ward-Hoffmann rules lends strong support to a cationic synchronous mechanism. This is also confirmed by kinetic measurements proving this reaction to be first order over all. The kinetic data are shown to fit the Hammett equation using cr-values for cyclopropyl bromides and o + -values for geminal cyclopropyl dichlorides, respectively. The validity of the Woodward-Hoffmann-De Puyrule (according to which in synchronous reactions leaving groups situated endo are strongly favored over those situated exo) is tested in corresponding experiments involving condensed ring systems. I. Zum Problem der nukleophilen Substitution an Cyclopropylsystemen In der vorliegenden Arbeit werden die Reaktionen von 2-phenylsubstituierten Cyclopropylhalogeniden unter typischen SN2-Bedingungen (Umsetzung mit Natriumiodid in Aceton) untersucht. Zunächst 
  Reference    Z. Naturforsch. 34b, 464—480 (1979); eingegangen am 10. August/19. Dezember 1978 
  Published    1979 
  Keywords    Ring Opening, Woodward-Hoffmann Rules, Allylic Cations, Dimerisation, 1, 5-Hexadienes 
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 TEI-XML for    default:Reihe_B/34/ZNB-1979-34b-0464.pdf 
 Identifier    ZNB-1979-34b-0464 
 Volume    34