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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 116 (1985), S. 1133-1140 
    ISSN: 1434-4475
    Keywords: Enazidoesters ; Cathodic reduction ; α-Aminocinnamic esters ; α-N,N-Diacylaminocinnamic esters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Several ring-substituted α-azidocinnamic and β-heterocyclic α-azidoacrylic esters are subject to cathodic reduction under aprotic and protic conditions. Good to excellent yields of rather labile dehydroaminoacid derivatives resp. stableN,N-diacylated enaminoesters are selectively obtainable. The compounds are characterised by spectroscopic methods (1H-NMR, IR, MS).
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1434-4475
    Keywords: Cathodic reduction ; Nitro-α-azido cinnamic esters ; Amino-α-azido cinnamic esters ; Hydroxylamino-α-azido cinnamic esters ; 4,α-Diamino cinnamic esters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Cathodic reduction of nitro-substituted azidocinnamic esters on mercury under aprotic and protic conditions was studied. Nitro and azido groups behave as independent entities so that selectively amino- resp. hydroxylamino-α-azido compounds are obtained, which could not be synthesised by conventional methods. Under aprotic conditions, with added acetic anhydride, medium yields of acylated 4-hydroxylamino- and 4-amino-α-cinnamic acid derivatives are isolated. Evidence of homogeneous electron transfer from nitroanion radicals to azido groups is given.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1434-4475
    Keywords: Enazidoketones ; Enaminoketones ; 2-Acetoxy-3-amino-dienes-(2,4) ; Cathodic reduction mechanism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract Die kathodische Synthese von Enaminoketonen aus ungesättigten Azidoketonen wurde auf heteroaromatisch substituierte und auf rein aliphatische Derivate übertragen. Zum Reduktionsmechanismus wurde der Einfluß verschiedener Stellen der Protonierung (am N1 der N3-Gruppe bzw. an der Carbonylgruppe), abhängig von Potential und Säurestärke, untersucht. Aldehydische Gruppen als weitere funktionelle Gruppen im Enazid werden leichter als die Vinylazide reduziert. Die rein aliphatischen Enazidoketone ergeben bei reduktiver Acylierung konjugierte Diene.
    Notes: Abstract The cathodic preparation of enamino ketones from enazidoketones has been generalised to include heteroaromatic and aliphatic derivatives. Mechanistically the role of different sites of protonation, either on N1 of the N3-group or on carbonyl depending on electrolysis potential and acid strength, apparent by product distribution, is clarified. Aldehydic groups are preferentially reduced compared to the vinylazide part. Purely aliphatic azidoketones yield conjugated dienes under reductive acetylation, which might be useful for cycloaddition reactions.
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  • 4
    ISSN: 1434-4475
    Keywords: Electroorganic syntheses ; Electrolysis cell ; Aprotonic solvents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A versatile electrolysis cell is presented, stable to common organic solvents and easy to handle, which allows organic electrosyntheses to be performed in rather short time under conditions of low voltage, exact separation of anode and cathode compartment and good potential control. Test examples of performance are given.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 115 (1984), S. 523-531 
    ISSN: 1434-4475
    Keywords: Cathodic reduction ; α-Azidostyrenes ; N-Acylenamides ; N,N-Diacylenamides ; N,N-Diacylamides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Cathodic reduction of non-terminal vinylazides on Hg cathodes in the presence of electrophiles gives reasonable yields of N-acylated enamines in an electrochemically totally irreversible reaction. In the presence of added H-donors rather high selectivity for formation of saturated amides is achieveable. The influence of reaction conditions on product distribution is discussed.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 117 (1986), S. 679-687 
    ISSN: 1434-4475
    Keywords: Unsaturated Azides and Amines ; α-Azido- and α-Amino-carbonylcompounds ; Cathodic reduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In the majority of compounds investigated the main reduction path starting from azido compounds under parotic conditions leads to the retainment of one nitrogen in the product molecules, provided an initial phase of consumption of residual water is overcome. Good to excellent yields of N-acylated or nicely stable N,N-diacetylated aminoderivatives are obtainable. Even a secondary position of the original N3-group prevents diacetylation completely by steric reasons. Vicinal halogen cause the loss of all nitrogen atoms as does the presence of H+ in the case of azidocarbonyl compounds. Where reduction potential of the starting azide lies within the reduction range ofAc 2O even high chemical yields of aminoderivatives are obtainable but with decrease of current efficiency. Reductive acetylation of benzoyl azide leads to the isolation of both rotational isomers of N-acetylbenzamide.
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  • 7
    ISSN: 1434-4475
    Keywords: α-Azidocinnamic ester ; Dehydroaminoacid derivatives ; Cathodic reduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Cathodic reduction of α-azidocinnamic ester under aprotic conditions on Hg, Pt, or graphite electrodes can be directed to high yields of N,N-diacylated dehydroaminoacid derivates (f.i. addition of acetic anhydride) or to almost quantitative yields of α-aminocinnamic ester in very pure form by careful addition of H+-donors. The dehydroamino compounds in turn can be further reduced to the corresponding saturated compounds by following H+-addition and changed electrolysis potential. Almost no dimerization occurs.
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  • 8
    ISSN: 1434-4475
    Keywords: Acid azides ; N,N-Diacylamides ; 1-Acyloxy-1-diacetyl-aminomethanes ; Lithiumion-azide complexes ; Cathodic reduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The cathodic reduction of the O=C-N3-system in aprotic solvent in the presence of anhydrides proves to be a convenient way to triacylammonia derivatives. Using the complexation of Li+ ions with the acid azide this synthetic methods can start from non-dangerous acid halides. The complex formation constant has been estimated and the chemical stability of N,N-diacylamides produced has been investigated. Mechanistic details about the role of Li+-ions in these electrolyses are given. Further reduction of the triacylammonia derivatives at more negative potentials results in protected aldehydic functions, i.e. 1-acyloxy-1-diacylaminomethanes, in good yields.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 113 (1982), S. 37-41 
    ISSN: 1434-4475
    Keywords: Sulfur dioxide reduction ; Sulfones ; Sulfinic esters, cyclic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Reaktion des elektrolytisch erzeugten SO 2 − -Anionradikals mit 1,θ-Dihalogeniden führt zu schwefelhaltigen Heterocyclen wie Oxathiolan-, Oxathian-, Thian- und Thiepanoxiden. 1,2-Dihalogenide geben durch reduktive Eliminierung Olefine.
    Notes: Abstract The reaction of the electrolytically generated SO 2 − anion radical with 1,θ-dihalides is used for the synthesis of sulfur containing heterocycles like oxathiolane-, oxathiane-, thiane- and thiepane-oxides. 1,2-Dihalides are reductively deblocked to give olefines.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 117 (1986), S. 1185-1193 
    ISSN: 1434-4475
    Keywords: α-Azidochalcones ; Cathodic reduction ; 2-Aminopropen-2-ones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die kathodische Reduktion von α-Azidopropenon erweist sich als ausgezeichneter Weg, um selektiv zu Enaminen zu gelangen, ohne (wie chemische Reduktionsmittel) auch andere Gruppierungen anzugreifen. Durch die Kontrolle von Protonierungs- bzw. Acetylierungsschritten lassen sich die stabileren N-Acetylamine erhalten. Das niedrig liegende Reduktionspotential der N,N-Diacetylamino-propenone verhindert, daß sie in einer Einstufensynthese bei der Reduktion der Azidochalkone unter stark acylierenden Bedingungen erhältlich sind. Das voltammetrische Verhalten der Azide und ihr Reaktionsweg bei der kathodischen Reduktion werden diskutiert.
    Notes: Abstract Cathodic reduction of α-azidochalcones under slightly protic conditions proves to be an excellent method for a selective conversion of the azido function to an amino group without affecting other reducible parts of the molecules. The amino-propenones retain theZ-configuration about the C=C-bond of the starting material, whereas N-acetyl derivatives, obtained under mildly acetylating conditions, are partially isomerised. The low reduction potential of N,N-diacetyl-enamines of this type prevents their direct one step synthesis by electrolysis of azidochalcones under strongly acetylating conditions. The voltammetric behaviour of the azides and their reduction pathway is discussed.
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