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  • 1960-1964  (4)
  • 1900-1904
  • 1890-1899
  • 1820-1829
  • 1962  (4)
  • Isocyanates  (2)
  • Natural products  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 98-111 
    ISSN: 0570-0833
    Keywords: Mass spectrometry ; Natural products ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mass spectrometry is a very useful method for the determination of the structure of organic compounds although the technique has not yet been widely employed in this field. Of particular interest is the high sensitivity of the instrument, making possible the use of very small amounts of sample, and the information obtainable regarding the size of the molecule and position of the groups therein. A certain volatility is required and the choice of a suitable derivative is, therefore, sometimes of importance. The fragmentations of the molecules in the ion source may be considered as reactions of “carbonium ions without solvent.” The application of the method in the determination of the structure of some natural products is outlined, using lipids, amino acids, peptides and alkaloids as examples.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 178-195 
    ISSN: 0570-0833
    Keywords: Enzyme catalysis ; Natural products ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Micro-organisms form enzymes that catalyze many reactions which are difficult to carry out in the laboratory or which involve many steps. Enzymes even react with substances which are normally foreign to them. The frequently high stereospecificity of microbiological reactions is of particular significance. The most important types of reactions are: hydroxylations, dehydrogenations (oxidations), and hydrogenations (reductions), cleavage of ester and C-C bonds, and transglycosidations. The variety of the compounds converted is extremely great.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 617-621 
    ISSN: 0570-0833
    Keywords: Isocyanates ; Phosphorus ; Silicon ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several aminoaryl esters of phosphoric and thiophosphoric acids were prepared by the reaction of phosphorus pentahalides with nitrophenols, followed by catalytic hydrogenation, or by treating aminophenols with phosphorus trihalides and oxidation to pentavalent phosphorus. These amino esters were then converted into isocyanato esters by the action of phosgene. Isocyanates of phosphonates have been synthetized on the same principle, as well as via the Arbusov reaction of halogen-substituted isocyanates with trialkyl phosphites. The reaction of silicon halides or alkylhalogenosilanes with aminophenols yielded aminoaryl esters of silicic acid or its derivatives, which could also be treated with phosgene to convert them into isocyanato esters.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 1 (1962), S. 621-625 
    ISSN: 0570-0833
    Keywords: Carbodiimides ; Isocyanates ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Carbodiimides are formed with simultaneous evolution of CO2 by the reaction of basic catalyst with sterically hindered isocynates. Another generally applicable synthesis of carbodiimides involves intermediate formation of cyclic adducts of isocyanates and carbodiimides, which, upon cleavage, exchange the isocyanate and carbodiimide functions. Both processes are suitable for the preparation of polycarboiimides. Several commercial applications of mono- and polycarbodiimides are pointed out.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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