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  • 1
    ISSN: 1588-2837
    Keywords: Phthalimide ; methylamine ; aminolysis ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In aqueous methylamine buffers of pH 10.21–11.25 nucleophilic cleavage of ionized (S−) phthalimide and general base-catalyzed cleavage of nonionized (SH) phthalimide is observed.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1588-2837
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract General base-catalyzed and uncatalyzed nucleophilic cleavage of both unionized (SH) and ionized (S−) phthalimide have been observed in ethane-1,2-diamine buffer solutions of pH 7.46–8.60. General base catalysis appears to be insignificant in the pH range of 9.17–10.10.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 7 (1994), S. 518-524 
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of the nucleophilic cleavage of phthalimide (PTH) in buffer solutions of ammonia and pyrrolidine were determined. The reaction rates for ammonolysis of PTH revealed a buffer-catalysed second-order term in the rate law, but the reaction rates for pyrrolidinolysis of PTH showed buffer-catalysed second- and third-order terms in the rate law. Both ammonia and pyrrolidine revealed nucleophilic reactivity towards ionized PTH (S-) only within the pH range of the present study. This is attributed to the occurrence of intramolecular general base-acid catalysis. General base catalysis is detected in the reactions of pyrrolidine with both non-ionized PTH (SH) and S-. The general base-catalysed third-order rate constant for pyrrolidinolysis of SH is nearly 28 times larger than that of S-.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The reaction rates of the cleavage of phthalimide (PTH) were studied at 30°C in buffer solutions of trimethylamine, triethylamine, triethanolamine, carbonate, piperidine, dimethylamine, morpholine, piperazine and N-methylpiperazine at different pH values. The reactivity of carbonate, triethylamine and triethanolamine toward PTH could not be detected under the experimental conditions applied. However, triethylamine revealed nucleophilic reactivity toward non-ionized PTH (SH). The steric requirements of triethylamine and triethanolamine are ascribed to the absence of nucleophilic reactivities of these amines toward SH. Secondary amines show nucleophilic reactivity toward both SH and ionized PTH (S-). The absence of nucleophilic reactivity of trimethylamine and the presence of nucleophilic reactivity of secondary amines toward S- are attributed to the occurrence of intramolecular general acid-base catalysis due to the presence of a mobile proton at the nucleophilic site of the nucleophile. Intermolecular general base catalysis was observed in the reactions of SH with all secondary amines except piperidine and such catalysis could be detected in the reactions of S- with morpholine, piperazine and N-methylpiperazine. Nucleophilic second-order rate constants for the reactions of secondary amines with SH (k1) and S- (k2) reveal the Brønsted plots of slopes of ca 0.8 and 0.3, respectively. Similarly, the general base-catalysed third-order rate constants (k4) for the reactions of secondary amines with SH yield a Brønsted plot of slope 1.2. These observations suggest the occurrence of diffusion-controlled trapping stepwise and pre-association stepwise mechanisms in the aminolysis of non-ionized and ionized phthalimide, respectively.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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