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1976 (1)
1975 (1)
1Author    Requires cookie*
 Title    Die Analytische Bedeutung des Ortho-Effektes in der Massenspektrometrie: Untersuchungen von Benzoe-und Thiobenzoesäure-Derivaten Spectroscopic Investigations, I X 1 The A nalytical Importance of the Ortho Effect in Mass Spectrom etry: Investigations of Benzoic and Thiobenzoic Acid Derivatives  
 Abstract    J ü r g e n M a r t e n s 2, K l a u s P r a e f c k e u n d H e l m u t S c h w a r z The mass-spectrometric investigation of esters and thiolesters of benzoic, thiobenzoic, salicylic and thiosalicylic esters shows that an analytical distinction with aid of the ortho effect is only possible under certain conditions between 1,2 -disubstituted aromatic compounds and the other constitutional isomers. Absent or small intensive signals of rearrangement-ions do not exclude such a constitution. The apparent anomalous behaviour of the S-methyl, S-tolyl and O-tolyl esters is rationalized by energy considerations. The influence of the enthalpy of formation of the neutral particles on the product distribution (a-cleavage/ortho effect) is discussed. 
  Reference    (Z. Naturforsch. 30b, 259—262 [1975]; eingegangen am 22. Oktober 1974) 
  Published    1975 
  Keywords    Esters, Thiolesters, Ortho-Effect 
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 TEI-XML for    default:Reihe_B/30/ZNB-1975-30b-0259.pdf 
 Identifier    ZNB-1975-30b-0259 
 Volume    30 
2Author    Rupert Herrmann, Helmut SchwarzRequires cookie*
 Title    Mechanisms of Electron Impact Induced Elimination of Methanol from ortho-and para-Substituted Benzoic Acid Methyl Ester  
 Abstract    Using deuterium labelled compounds the mechanisms of methyl as well as methanol elimination from the title compounds have been established. It can be shown that in the case of 4-methoxy-methyl benzoic acid methyl ester the unusual methanol elimination from the [M-methyl]+ ion probably proceeds via the formation of a jr-complex and a ring expansion reaction. In addition to this novel fragmentation some oriAo-effects and other fragmentation reactions useful for an analytical identification of the ortho/para-isomers by means of mass spectrometry are discussed. 
  Reference    (Z. Naturforsch. 31b, 870—875 [1976]; eingegangen am 19. Dezember 1975) 
  Published    1976 
  Keywords    ortho-Effect, Hydrogen Scrambling, Ring Expansion, Rearrangement 
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 TEI-XML for    default:Reihe_B/31/ZNB-1976-31b-0870.pdf 
 Identifier    ZNB-1976-31b-0870 
 Volume    31