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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1975 (1975), S. 1952-1955 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Acyloxy(trialky1)ammonium SaltsAlkylation of O-benzoyl-N,N-dimethylhydroxylamine (2) with trimethyloxonium tetrafluoroborate gives the benzoyloxy(trimethy1)ammonium salt 3t. Methyl iodide, however, yields dimethylmethyleneammonium iodide (7). Sodium tetraphenylborate and 3 undergo anion exchange to benzoyloxy(trimethy1)ammonium tetraphenylborate (1). With sodium benzoate a Polonovski-type reaction step takes place to give dimethylaminomethyl benzoate (6) with elimination of benzoic acid. Similarly the reaction of trimethylamine and dibenzoyl peroxide leads to 6.
    Notes: Die Umsetzung von O-Benzoyl-N,N-dimethylhydroxylamin (2) mit Trimethyloxonium-tetra- fluoroborat führt zum Benzoyloxy(trimethyl)ammoniumsalz 3, wahrend mit Methyljodid als Sekundärprodukt Dimethylmethylenammoniumjodid (7) erhalten wird. Mit Natrium- tetraphenylborat reagiert 3 unter Anionenaustausch zu Benzoyloxy(trimethyl)ammonium- tetraphenylborat (1), während mit Natriumbenzoat in Art eines Schrittes der Polonovski- Reaktion unter Abspaltung von Benzoesäure Dimethylaminomethyl-benzoat (6) entsteht. Analog führt die Umsetzung von Trimethylamin und Dibenzoylperoxid zu 6.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1975 (1975), S. 1790-1796 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Acyloxymethyl(dialky1)amines and -(trialkyl)ammonium saltsThe reaction of dialkyl(methylene)ammonium halides 1 with sodium salts of carboxylic acids yields the carboxylic esters of dialkylamino methanol 2, which can be alkylated by means of alkyl iodide or bromide, dimethyl sulfate or trimethyloxonium tetrafluoroborate to quaternary salts 4. Cleavage of methylenebis(dimethy1amine) (5) with trichloroacetic anhydride affords dimethyl(methylene)ammonium trichloroacetate (3), and with chloroacetic anhydride diniethylaminomethyl chloroacetate (7) is formed. With dichloroacetic anhydride, however, 1,I -dichloro-2-(dimethylamino)propionic acid (14) is obtained as a secondary product. In all cases the corresponding N,N-dialkylcarboxamides are also isolable as side products. The methylenediamine cleavage reactions can also be achieved with dicarboxylic anhydrides, e. g. compounds 18 and 20 are synthesized from 5 on reaction with succinic or phthalic anhydride.
    Notes: Durch Umsetzung von Dialkyl(methylen)ammoniumhalogeniden 1 mit Natriumsalzen von Carbonsäuren werden Carbonsä,ureester von (Dialky1amino)methanolen 2 erhalten, die durch Alkyljodide oder -bromide, durch Dimethylsulfat oder Trimethyloxonium-tetrafluoro- borat in die Quartärsalze 4 übergeführt werden können. Die Spaltung von Methylenbis- (dimethylamin) (5) mit Trichloressigsäureanhydrid liefert Dimethyl(methylen)ammonium- trichloracetat (31), die mit Chloressigsäureanhydrid Dimethylaminomethylchloracetat (7), während mit Dichloressigsäureanhydrid als Sekundärprodukt 1,l -Dichlor-2-(dimethylamino)- propionsäure (14) erhalten wird; als Nebenprodukte sind in allen Fällen die entsprechenden Carbonsäuredialkylamide zu isolieren. Auch mit Anhydriden von Dicarbonsäuren können Methylendiaminspaltungen ausgeführt werden. Aus Bernsteinsäure- oder Phthalsäureanhydrid und 5 entstehen beispielsweise 18 bzw. 20.
    Type of Medium: Electronic Resource
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  • 3
    Publication Date: 2014-02-26
    Description: The photoassociation process shows strong dependence on the temporal duration of the electromagnetic field pulses and their frequencies. This dependence is investigated using quantum mechanical simulations that include all ranges of impact parameters and contributions from bound-to-bound transitions. The photoassociation yield of mercury atoms to produce excimer dimers is enhanced for short (ps) and for ultrashort (fs) pulse durations. Ultrashort laser pulses effectively overlap the entire range of free-to-bound transition, therefore achieving a maximum probability. Short pulses show a maximum in the photoassociation yield when their carrier frequency overlaps a particular free-to-bound spectroscopic resonance. Implications of these calculations on efforts to control bimolecular reactions are discussed.
    Keywords: ddc:000
    Language: English
    Type: reportzib , doc-type:preprint
    Format: application/postscript
    Format: application/pdf
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