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1Author    Von Alkoholat, Wolf-H GiindelRequires cookie*
 Title    Untersuchungen an quartären Pyridiniumsalzen, X [1] Eine Kondensationsreaktion von 3-Cyanpyridiniumsalzen bei Einwirkung A Condensation Reaction of 3-Cyanopyridinium Salts on Addition of Alcoxides  
 Abstract    1-Benzyl-3-cyanopyridinium salts, in the benzyl moiety differently substituted, react in boiling alcohol with alcoxides to derivatives of hexahydro-dipyrido[l,2-a:3',2'-c]-pyrrole. At 20 °C occurs rearrangement to derivatives of 2-amino-3-pyridinecarbaldehyde. 
  Reference    Z. Naturforsch. 35b, 490—493 (1980); eingegangen am 12. Dezember 1979 
  Published    1980 
  Keywords    Pyridinium Salts, Condensationreaction, Rearrangement 
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 TEI-XML for    default:Reihe_B/35/ZNB-1980-35b-0490.pdf 
 Identifier    ZNB-1980-35b-0490 
 Volume    35 
2Author    Wolf-H GündelRequires cookie*
 Title    Reaktionen von Cyanpyridinium-Salzen mit Hydroxylamin Investigations of Quaternary Pyridinium Salts, XI [1] Reactions of Cyanopyridinium Salts with Hydroxylamine  
 Abstract    The preparation of quaternary pyridinium salts with amidoxime group in 2-, 3-and 4-position is described. The isomer with the substituent in 3-position rearranges on addition of base to a l-hydroxy-2-imino-3-pyridinecarbaldimine. The reaction of 3-cyano-pyridinium salts with hydroxylamine and potassium terf-butoxide gives derivatives of dipyrido[l,2-a: 3',4'-c]pyrrole. 
  Reference    Z. Naturforsch. 35b, 896—901 (1980); eingegangen am 21. März 1980 
  Published    1980 
  Keywords    Pyridinium Salts, Rearrangement, Condensation Reaction 
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 TEI-XML for    default:Reihe_B/35/ZNB-1980-35b-0896.pdf 
 Identifier    ZNB-1980-35b-0896 
 Volume    35 
3Author    Herbert Binder, Jürgen PalmtagRequires cookie*
 Title    Zur Reaktion zwischen Bortrifluorid und Natrium-diethylphosphit Darstellung und Reaktionen von Tris(diethylphosphitoboran) The Reaction between Borontrifluoride and Sodium Diethylphosphite Synthesis and Reactions of Tris(diethylphosphitoborane)  
 Abstract    Tris(diethylphosphitoborane) (2) can be synthesized by the reaction of BF3-0(C2H5)2 with sodium diethylphosphite. The chemical behaviour of this new compound and its NMR data are reported. 
  Reference    (Z. Naturforsch. 36b, 45—47 [1981]; eingegangen am 22. Juli/9. September 1980) 
  Published    1981 
  Keywords    Tris(diethylphosphitoborane), Reactions, Rearrangement 
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 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-0045.pdf 
 Identifier    ZNB-1981-36b-0045 
 Volume    36 
4Author    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 
5Author    EckehardV. Dehmlow, Roland KramerRequires cookie*
 Title      
 Abstract    The title compounds la—3c were prepared by stereoselective reduction of the respective dibromides. Pyrolysis gave allylic bromides (8, 9, 11) as primary and dienes (10, 12) as secondary products. Product ratios were independent of the stereochemistry of the starting materials. No differences of the rearrangement rates of the stereoisomers were observed in gas phase reactions of the derivatives of bicyclo[6.1.0]-and bicyclo[8.1.0]alkanes. With the larger bicyclo[10.1.0] derivatives, however, distinct differences in the thermal stability of cw-/fra«5-isomers4c/5cor 2c/3c were found in condensed phase. 
  Reference    Z. Naturforsch. 42b, 489—494 (1987); received September 24 1986 
  Published    1987 
  Keywords    Dibromocarbene Adducts, Stereoselective Debromination, Rearrangement, Allylic Bromides 
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 TEI-XML for    default:Reihe_B/42/ZNB-1987-42b-0489.pdf 
 Identifier    ZNB-1987-42b-0489 
 Volume    42 
6Author    Snezhana Bakalova, Ivanka KavrakovaRequires cookie*
 Title    Electronic Spectra and Photochemical Properties of Acetyldihydroquinolinones  
 Abstract    The absorption and luminescence properties o f 6-acetyl-2,3-dihydro-4(lH)-quinolinone are described and compared to those of the parent 2,3-dihydro-4(lH)-quinolinone. The character of the electronic transitions is determined by PPP quantum chemical calculations. An N-acyl migration leading to the form ation of 6-acetyl-2,3-dihydro-4(lH)-quinolinone takes place upon UV irradiation or heating with polyphosphoric acid o f 1-acetyl-2,3-dihydro-4(lH)-quinolinone. A radical mechanism of the photochemical rearrangem ent is proposed. 
  Reference    Z. Naturforsch. 47b, 1775—1778 (1992); received April 4 1992 
  Published    1992 
  Keywords    D ihydroquinolinone, Fluorescence, Rearrangement, Photochemical Properties 
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 TEI-XML for    default:Reihe_B/47/ZNB-1992-47b-1775.pdf 
 Identifier    ZNB-1992-47b-1775 
 Volume    47 
7Author    Grzegorz JackowskiRequires cookie*
 Title    Senescence-Related Changes in the Subcomplex Arrangement of the Major Light-Harvesting Chlorophyll a/b-Protein Complex of Photosystem II (LHCII) as Influenced by Cytokinin  
 Abstract    The major light-harvesting chlorophyll a /b -protein complex of photosystem II (LHCII) from fresh barley leaves could be resolved by non-denaturing IEF into five trimeric subcom­ plexes designated 1 -5 in order of decrasing pi value. IEF-based analysis of PSII particles isolated from leaves in which the processes of senescence were induced by detachement and dark-incubation in the presence of water for 0 -8 days let us reveal that substantial rearrangements of LHCII organization took place throughout the course of senescence com ­ prising a step-wise decline in relative abundance of subcom plexes 1 -3 (down to 0-58% of the initial abundance during 8 days of aging) and an increase in the relative abundance of the subcom plexes 4 and 5. Using SDS-PAGE and immunoblot analysis it was shown that the rearrangements were linked to the changes in the relative levels of LHCII apoproteins i.e. 26.7 and 25.6 kDa ones. The changes comprised the preferential disappearance of the 26.7 kDa polypeptide and an enrichment of 25.6 kD a one and most probably reflect the hetero­ geneity among LHCII apoproteins concerning their stability under the conditions of chi loss. Kinetin was able to repress the senescence-related rearrangements in LHCII subcomplex organization at late stages of aging (5 -8 days) by preventing over this time period the disap­ pearance of 26.7 kD a polypeptide and the enrichement of 25.6 kDa one. 
  Reference    Z. Naturforsch. 51c, 464 (1996); received Novem ber 23 1995/ 
  Published    1996 
  Keywords    Aging, Barley, Isoelectric Focusing, Polypeptide, Rearrangement 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0464.pdf 
 Identifier    ZNC-1996-51c-0464 
 Volume    51 
8Author    Rupert Herrmann, Helmut SchwarzRequires cookie*
 Title    On the Mechanism of Substituent Interaction During bhe Electron Impact Induced Ether Cleavage from para-Substituted Methoxymethvl Benzenes  
 Abstract    The unusual methyl elimination from para-substituted methoxy-methyl benzenes has been elucidated. It can be shown that two entirely different mechanisms contribute to the reaction: i) intramolecular hydrogen transfer onto the benzene ring (7r-complex formation) and ii) substituent migration via ring expansion. Alternative mechanisms as for instance transanular protonation of the ester function or substituent migration via valence bond isomers are not involved in the formation of the [M-methyl]+-ions. 
  Reference    (Z. Naturforsch. 31b, 1667—1672 [1976]; eingegangen am 24. September 1976) 
  Published    1976 
  Keywords    Mass Spectrometry, Intramolecular Protonation, t-Complex, Rearrangement, Ring Expansion 
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 TEI-XML for    default:Reihe_B/31/ZNB-1976-31b-1667.pdf 
 Identifier    ZNB-1976-31b-1667 
 Volume    31 
9Author    Umlagerung Synthese, Eigenschaften Diphenylphosphinosubstituierter Uracile, Jochen Ellermann, AlfonsA M DemuthRequires cookie*
 Title    Chemie polyfunktioneller Moleküle, 74 [1] [1] Synthesis, Rearrangement and Properties of Diphenylphosphino Substituted Uracils  
 Abstract    5-Bromo-uracil (2) with chloro-diphenylphosphine and triethylamine gives 5-bromo-N(1),N(3)-bis(diphenylphosphino)-uracil (3). In moist acetone, 3 is hydrolyzed to 5-bromo-N(l)-diphenylphosphino-uracil (4). 3 reacts with n-butyllithium under rearrangement and, with HCl, under elimination of a PPh2-group, forms C(5)-diphenylphosphino-uracil (7 a). Recrystallization of 7 a from ethanol yields the ethanol-1:1-adduct 7 b. Heating of 7 a in dimethylsulfoxide with D20 yields the N(l),N(3)-dideutero-C(5)-diphenylphosphino-uracil (7 c). All compounds were characterized by infrared, Raman, iH, 31 P NMR and mass spectra. 7 a shows a very small antitumor activity. 
  Reference    Z. Naturforsch. 38b, 1165—1172 (1983); eingegangen am 19. Mai 1983 
  Published    1983 
  Keywords    Diphenylphosphino Substituted Uracils, Rearrangement, NMR Spectra, Vibrational Spectra, Mass Spectra 
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 TEI-XML for    default:Reihe_B/38/ZNB-1983-38b-1165.pdf 
 Identifier    ZNB-1983-38b-1165 
 Volume    38