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'Neighbouring Group Participation' in keywords
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1999 (1)
1983 (1)
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1976 (1)
1Author    S. K. Dubey, Satyavan Sharma, R. N. IyerRequires cookie*
 Title    An Unusual N-Dealkylation-Neighbouring Group Participations of Oximino Function [1]  
 Abstract    Reaction of N,N-dialkyl-/?-aminoketones (5 and 7) with hydroxylamine hydrochloride in pyridine results in the dealkylated oximine (6). The mechanism of this N-dealkylation may be explained as due to the neighbouring group participation of the oximine formed during the reaction. 
  Reference    Z. Naturforsch. 34b, 1424—1426 (1979); received May 7 1979 
  Published    1979 
  Keywords    N-Dealkylation, Hydroxylamine Hydrochloride Pyridine, Neighbouring Group Participation 
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 TEI-XML for    default:Reihe_B/34/ZNB-1979-34b-1424.pdf 
 Identifier    ZNB-1979-34b-1424 
 Volume    34 
2Author    Hong Zhanga, Yali Wanga, Rene Thiirmera, Khalid Parvez, Iqbal Choudhary, A. Tta-, Ur-R Ahm Anb, Wolfgang Voelter3Requires cookie*
 Title    Neighbouring Group Participation of C-6 Substituents of Glucose Derivatives on the Stereoselectivity of the N-Glycosidic Linkage of Glycopeptides  
 Abstract    The first example of a glycopeptide with a direct /V-a-glycosidic linkage between the trisac­ charide and the amino acid residue was found in the glomerular basement membrane of rats. In connection with the total synthesis of nephritogenoside, glycosyl azides with different protecting groups and carbohydrate chain lengths are synthesized, reduced to the corre­ sponding glycosyl amines and coupled with Z-Asp-O Bzl. Remarkable differences in the a:ß ratio of the condensation products are observed, caused by neighbouring group participation. 
  Reference    Z. Naturforsch. 54b, 692—6 (1999); received February 2. 1999 
  Published    1999 
  Keywords    Oligosaccharide Synthesis, Glycopeptides, Neighbouring Group Participation 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-0692.pdf 
 Identifier    ZNB-1999-54b-0692 
 Volume    54 
3Author    Rupert Herrmann, Helmut SchwarzRequires cookie*
 Title    On the Isomerisation and Fragmentation of Butenoic Acid Methyl Esters under Electron Impact  
 Abstract    Ion On the contrary to the photochemical behavior the title compounds do not isomerise to a common intermediate prior to or during electron impact induced fragmentation. The unusual methyl elimination from the trans (2)-butenoic acid methyl ester probably is ac-companied by a concerted [1.3] methoxy rearrangement from the ester function on to the ß carbon atom. 
  Reference    (Z. Naturforsch. 31b, 1013—1014 [1976]; eingegangen am 22. März 1976) 
  Published    1976 
  Keywords    Structure, Neighbouring Group Participation, Alkoxy Rearrangement, Mass Spectrometry, Unsaturated Esters 
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 TEI-XML for    default:Reihe_B/31/ZNB-1976-31b-1013_n.pdf 
 Identifier    ZNB-1976-31b-1013_n 
 Volume    31 
4Author    Bernhard Ciommer, Helmut SchwarzRequires cookie*
 Title    Zur intermediären Existenz von Ethylenfluoronium-Ionen in der Gasphase On the Intermediary Existence of Gaseous Ethylen Fluoronium Ions  
 Abstract    The long-sought ethylen fluoronium ion (2) is generated as an intermediate in the dissociative ionization of l-fluoro-2-(^-methyl)phenoxy ethane (4). However, prior to collisionally induced dissociation 2 undergoes ring-opening, associated with hydrogen migration, to form 1-fluoroethyl cation (3). Other decomposition pathways of the molecular ions of 4 involve (i) direct formation of 3 via a combination of C-O-cleavage (loss of ArO -) and [1,2] hydrogen migration (18%) and (ii) complete positional loss of the a-and ß-methylene hydrogen atoms (34%). The remaining 48% of the molecular ions of 4 dissociate via anchimeric assistance of the fluorine in the elimination of ArO -, thus giving rise to the formation of 2. 
  Reference    Z. Naturforsch. 38b, 635—638 (1983); eingegangen am 23. Dezember 1982 
  Published    1983 
  Keywords    Fluoronium Ions, Neighbouring Group Participation, Gaseous Ions, Collisional Activation, Mass Spectrometry 
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 TEI-XML for    default:Reihe_B/38/ZNB-1983-38b-0635.pdf 
 Identifier    ZNB-1983-38b-0635 
 Volume    38